Quadruped Robots [omni.isaac.quadruped]
Quadruped Controller
- class A1QPController(name: str, _simulate_dt: float, waypoint_pose=None)
[summary]
A1 QP controller as a layer.
An implementation of the QP controller[1]
References
- [1] Bledt, Gerardo, et al. “MIT Cheetah 3: Design and control of a robust, dynamic quadruped robot.”
2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS). IEEE, 2018.
- advance(dt: float, measurement: omni.isaac.quadruped.utils.a1_classes.A1Measurement, path_follow=False, auto_start=True) numpy.array
[summary]
Perform torque command generation.
- Parameters
world. (dt {float} -- Timestep update in the) –
robot. (measurement {A1Measurement} -- Current measurement from) –
in (path_follow {bool} -- True if a waypoint is pathed) –
not (false if) –
automatically (auto_start {bool} -- True to start trotting after 1 second) –
pressed (False for start trotting after "Enter" is) –
- Returns
np.ndarray – The desired joint torques for the robot.
- ctrl_state_reset() None
[summary]
reset _ctrl_states and _ctrl_params to non-default values
- reset() numpy.ndarray
[summary]
Reset the ctrl states.
- set_target_command(base_command: Union[List[float], numpy.ndarray]) None
[summary]
Set target base velocity command from joystick
- Parameters
base_command{Union[List[float] –
robot (np.ndarray} -- velocity commands for the) –
- setup() None
[summary]
Reset the ctrl states.
- switch_mode()
[summary]
toggle between stationary/moving mode
- update(dt: float, measurement: omni.isaac.quadruped.utils.a1_classes.A1Measurement)
[summary]
Fill measurement into _ctrl_states :param dt {float} – Timestep update in the world.: :param measurement {A1Measurement} – Current measurement from robot.:
- class A1RobotControl
[summary]
The A1 robot controller This class uses A1CtrlStates to save data. The control joint torque is generated using a QP controller
- generate_ctrl(desired_states: omni.isaac.quadruped.utils.a1_desired_states.A1DesiredStates, input_states: omni.isaac.quadruped.utils.a1_ctrl_states.A1CtrlStates, input_params: omni.isaac.quadruped.utils.a1_ctrl_params.A1CtrlParams) None
[summary]
main function, generate foot ground reaction force using QP and calculate joint torques
- Parameters
states (input_states {A1CtrlStates} -- the control) –
states –
parameters (input_params {A1CtrlParams} -- the control) –
- update_plan(desired_states: omni.isaac.quadruped.utils.a1_desired_states.A1DesiredStates, input_states: omni.isaac.quadruped.utils.a1_ctrl_states.A1CtrlStates, input_params: omni.isaac.quadruped.utils.a1_ctrl_params.A1CtrlParams, dt: float) None
[summary]
update swing leg trajectory and several counters
- Parameters
states (input_states {A1CtrlStates} -- the control) –
states –
parameters (input_params {A1CtrlParams} -- the control) –
time-step. (dt {float} -- The simulation) –
Quadruped Robots
- class Anymal(prim_path: str, name: str = 'anymal', usd_path: Optional[str] = None, position: Optional[numpy.ndarray] = None, orientation: Optional[numpy.ndarray] = None)
The ANYmal quadruped
- advance(dt, command)
[summary]
compute the desired torques and apply them to the articulation
Argument: dt {float} – Timestep update in the world. command {np.ndarray} – the robot command (v_x, v_y, w_z)
- apply_action(control_actions: omni.isaac.core.utils.types.ArticulationAction) None
Apply joint positions, velocities and/or efforts to control an articulation
- Parameters
control_actions (ArticulationAction) – actions to be applied for next physics step.
indices (Optional[Union[list, np.ndarray]], optional) – degree of freedom indices to apply actions to. Defaults to all degrees of freedom.
Hint
High stiffness makes the joints snap faster and harder to the desired target, and higher damping smoothes but also slows down the joint’s movement to target
For position control, set relatively high stiffness and low damping (to reduce vibrations)
For velocity control, stiffness must be set to zero with a non-zero damping
For effort control, stiffness and damping must be set to zero
Example:
>>> from omni.isaac.core.utils.types import ArticulationAction >>> >>> # move all the robot joints to the indicated position >>> action = ArticulationAction(joint_positions=np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04])) >>> prim.apply_action(action) >>> >>> # close the robot fingers: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 0.0 >>> action = ArticulationAction(joint_positions=np.array([0.0, 0.0]), joint_indices=np.array([7, 8])) >>> prim.apply_action(action)
- apply_visual_material(visual_material: omni.isaac.core.materials.visual_material.VisualMaterial, weaker_than_descendants: bool = False) None
Apply visual material to the held prim and optionally its descendants.
- Parameters
visual_material (VisualMaterial) – visual material to be applied to the held prim. Currently supports PreviewSurface, OmniPBR and OmniGlass.
weaker_than_descendants (bool, optional) – True if the material shouldn’t override the descendants materials, otherwise False. Defaults to False.
Example:
>>> from omni.isaac.core.materials import OmniGlass >>> >>> # create a dark-red glass visual material >>> material = OmniGlass( ... prim_path="/World/material/glass", # path to the material prim to create ... ior=1.25, ... depth=0.001, ... thin_walled=False, ... color=np.array([0.5, 0.0, 0.0]) ... ) >>> prim.apply_visual_material(material)
- property articulation_handle: int
A handler to the articulation
The handler is a unique identifier used by the Dynamic Control extension to manage the articulation
- Returns
handle
- Return type
int
Example:
>>> prim.articulation_handle 1116691496961
- disable_gravity() None
Keep gravity from affecting the robot
Example:
>>> prim.disable_gravity()
- property dof_names: List[str]
List of prim names for each DOF.
- Returns
prim names
- Return type
list(string)
Example:
>>> prim.dof_names ['panda_joint1', 'panda_joint2', 'panda_joint3', 'panda_joint4', 'panda_joint5', 'panda_joint6', 'panda_joint7', 'panda_finger_joint1', 'panda_finger_joint2']
- property dof_properties: numpy.ndarray
Articulation DOF properties
DOF properties Index
Property name
Description
0
typeDOF type: invalid/unknown/uninitialized (0), rotation (1), translation (2)
1
hasLimitsWhether the DOF has limits
2
lowerLower DOF limit (in radians or meters)
3
upperUpper DOF limit (in radians or meters)
4
driveModeDrive mode for the DOF: force (1), acceleration (2)
5
maxVelocityMaximum DOF velocity. In radians/s, or stage_units/s
6
maxEffortMaximum DOF effort. In N or N*stage_units
7
stiffnessDOF stiffness
8
dampingDOF damping
- Returns
named NumPy array of shape (num_dof, 9)
- Return type
np.ndarray
Example:
>>> # get properties for all DOFs >>> prim.dof_properties [(1, True, -2.8973, 2.8973, 1, 1.0000000e+01, 5220., 60000., 3000.) (1, True, -1.7628, 1.7628, 1, 1.0000000e+01, 5220., 60000., 3000.) (1, True, -2.8973, 2.8973, 1, 5.9390470e+36, 5220., 60000., 3000.) (1, True, -3.0718, -0.0698, 1, 5.9390470e+36, 5220., 60000., 3000.) (1, True, -2.8973, 2.8973, 1, 5.9390470e+36, 720., 25000., 3000.) (1, True, -0.0175, 3.7525, 1, 5.9390470e+36, 720., 15000., 3000.) (1, True, -2.8973, 2.8973, 1, 1.0000000e+01, 720., 5000., 3000.) (2, True, 0. , 0.04 , 1, 3.4028235e+38, 720., 6000., 1000.) (2, True, 0. , 0.04 , 1, 3.4028235e+38, 720., 6000., 1000.)] >>> >>> # property names >>> prim.dof_properties.dtype.names ('type', 'hasLimits', 'lower', 'upper', 'driveMode', 'maxVelocity', 'maxEffort', 'stiffness', 'damping') >>> >>> # get DOF upper limits >>> prim.dof_properties["upper"] [ 2.8973 1.7628 2.8973 -0.0698 2.8973 3.7525 2.8973 0.04 0.04 ] >>> >>> # get the last DOF (panda_finger_joint2) upper limit >>> prim.dof_properties["upper"][8] # or prim.dof_properties[8][3] 0.04
- enable_gravity() None
Gravity will affect the robot
Example:
>>> prim.enable_gravity()
- get_angular_velocity() numpy.ndarray
Get the angular velocity of the root articulation prim
- Returns
3D angular velocity vector. Shape (3,)
- Return type
np.ndarray
Example:
>>> prim.get_angular_velocity() [0. 0. 0.]
- get_applied_action() omni.isaac.core.utils.types.ArticulationAction
Get the last applied action
- Returns
last applied action. Note: a dictionary is used as the object’s string representation
- Return type
Example:
>>> # last applied action: joint_positions -> [0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04] >>> prim.get_applied_action() {'joint_positions': [0.0, -1.0, 0.0, -2.200000047683716, 0.0, 2.4000000953674316, 0.800000011920929, 0.03999999910593033, 0.03999999910593033], 'joint_velocities': [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0], 'joint_efforts': [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]}
- get_applied_joint_efforts(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the efforts applied to the joints set by the
set_joint_effortsmethod- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
all or selected articulation joint applied efforts
- Return type
np.ndarray
Example:
>>> # get all applied joint efforts >>> prim.get_applied_joint_efforts() [ 0. 0. 0. 0. 0. 0. 0. 0. 0.] >>> >>> # get finger applied efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_applied_joint_efforts(joint_indices=np.array([7, 8])) [0. 0.]
- get_applied_visual_material() omni.isaac.core.materials.visual_material.VisualMaterial
Return the current applied visual material in case it was applied using apply_visual_material or it’s one of the following materials that was already applied before: PreviewSurface, OmniPBR and OmniGlass.
- Returns
the current applied visual material if its type is currently supported.
- Return type
Example:
>>> # given a visual material applied >>> prim.get_applied_visual_material() <omni.isaac.core.materials.omni_glass.OmniGlass object at 0x7f36263106a0>
- get_articulation_body_count() int
Get the number of bodies (links) that make up the articulation
- Returns
amount of bodies
- Return type
int
Example:
>>> prim.get_articulation_body_count() 12
- get_articulation_controller() omni.isaac.core.controllers.articulation_controller.ArticulationController
Get the articulation controller
Note
If no
articulation_controllerwas passed during class instantiation, a default controller of typeArticulationController(a Proportional-Derivative controller that can apply position targets, velocity targets and efforts) will be used- Returns
articulation controller
- Return type
Example:
>>> prim.get_articulation_controller() <omni.isaac.core.controllers.articulation_controller.ArticulationController object at 0x7f04a0060190>
- get_default_state() omni.isaac.core.utils.types.XFormPrimState
Get the default prim states (spatial position and orientation).
- Returns
an object that contains the default state of the prim (position and orientation)
- Return type
Example:
>>> state = prim.get_default_state() >>> state <omni.isaac.core.utils.types.XFormPrimState object at 0x7f33addda650> >>> >>> state.position [-4.5299529e-08 -1.8347054e-09 -2.8610229e-08] >>> state.orientation [1. 0. 0. 0.]
- get_dof_index(dof_name: str) int
Get a DOF index given its name
- Parameters
dof_name (str) – name of the DOF
- Returns
DOF index
- Return type
int
Example:
>>> prim.get_dof_index("panda_finger_joint2") 8
- get_enabled_self_collisions() int
Get the enable self collisions flag (
physxArticulation:enabledSelfCollisions)- Returns
self collisions flag (boolean interpreted as int)
- Return type
int
Example:
>>> prim.get_enabled_self_collisions() 0
- get_joint_positions(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the articulation joint positions
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Returns
all or selected articulation joint positions
- Return type
np.ndarray
Example:
>>> # get all joint positions >>> prim.get_joint_positions() [ 1.1999920e-02 -5.6962633e-01 1.3480479e-08 -2.8105433e+00 6.8284894e-06 3.0301569e+00 7.3234749e-01 3.9912373e-02 3.9999999e-02] >>> >>> # get finger positions: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_joint_positions(joint_indices=np.array([7, 8])) [0.03991237 3.9999999e-02]
- get_joint_velocities(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the articulation joint velocities
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Returns
all or selected articulation joint velocities
- Return type
np.ndarray
Example:
>>> # get all joint velocities >>> prim.get_joint_velocities() [ 1.91603772e-06 -7.67638255e-03 -2.19138826e-07 1.10636465e-02 -4.63412944e-05 3.48245539e-02 8.84692147e-02 5.40335372e-04 1.02849208e-05] >>> >>> # get finger velocities: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_joint_velocities(joint_indices=np.array([7, 8])) [5.4033537e-04 1.0284921e-05]
- get_joints_default_state() omni.isaac.core.utils.types.JointsState
Get the default joint states (positions and velocities).
- Returns
an object that contains the default joint positions and velocities
- Return type
Example:
>>> state = prim.get_joints_default_state() >>> state <omni.isaac.core.utils.types.JointsState object at 0x7f04a0061240> >>> >>> state.positions [ 0.012 -0.57000005 0. -2.81 0. 3.037 0.785398 0.04 0.04 ] >>> state.velocities [0. 0. 0. 0. 0. 0. 0. 0. 0.]
- get_joints_state() omni.isaac.core.utils.types.JointsState
Get the current joint states (positions and velocities)
- Returns
an object that contains the current joint positions and velocities
- Return type
Example:
>>> state = prim.get_joints_state() >>> state <omni.isaac.core.utils.types.JointsState object at 0x7f02f6df57b0> >>> >>> state.positions [ 1.1999920e-02 -5.6962633e-01 1.3480479e-08 -2.8105433e+00 6.8284894e-06 3.0301569e+00 7.3234749e-01 3.9912373e-02 3.9999999e-02] >>> state.velocities [ 1.91603772e-06 -7.67638255e-03 -2.19138826e-07 1.10636465e-02 -4.63412944e-05 245539e-02 8.84692147e-02 5.40335372e-04 1.02849208e-05]
- get_linear_velocity() numpy.ndarray
Get the linear velocity of the root articulation prim
- Returns
3D linear velocity vector. Shape (3,)
- Return type
np.ndarray
Example:
>>> prim.get_linear_velocity() [0. 0. 0.]
- get_local_pose() Tuple[numpy.ndarray, numpy.ndarray]
Get prim’s pose with respect to the local frame (the prim’s parent frame)
- Returns
first index is the position in the local frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the local frame
- Return type
Tuple[np.ndarray, np.ndarray]
Example:
>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame >>> position, orientation = prim.get_local_pose() >>> position [0. 0. 0.] >>> orientation [0. 0. 0.]
- get_local_scale() numpy.ndarray
Get prim’s scale with respect to the local frame (the parent’s frame)
- Returns
scale applied to the prim’s dimensions in the local frame. shape is (3, ).
- Return type
np.ndarray
Example:
>>> prim.get_local_scale() [1. 1. 1.]
- get_measured_joint_efforts(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Returns the efforts computed/measured by the physics solver of the joint forces in the DOF motion direction
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
all or selected articulation joint measured efforts
- Return type
np.ndarray
Example:
>>> # get all joint efforts >>> prim.get_measured_joint_efforts() [ 2.7897308e-06 -6.9083519e+00 -3.6398471e-06 1.9158335e+01 -4.3552645e-06 1.1866090e+00 -4.7079347e-06 3.2339853e-04 -3.2044132e-04] >>> >>> # get finger efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_measured_joint_efforts(joint_indices=np.array([7, 8])) [ 0.0003234 -0.00032044]
- get_measured_joint_forces(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the measured joint reaction forces and torques (link incoming joint forces and torques) to external loads
Note
Since the name->index map for joints has not been exposed yet, it is possible to access the joint names and their indices through the articulation metadata.
prim._articulation_view._metadata.joint_names # list of names prim._articulation_view._metadata.joint_indices # dict of name: index
To retrieve a specific row for the link incoming joint force/torque use
joint_index + 1- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
measured joint forces and torques. Shape is (num_joint + 1, 6). Row index 0 is the incoming joint of the base link. For the last dimension the first 3 values are for forces and the last 3 for torques
- Return type
np.ndarray
Example:
>>> # get all measured joint forces and torques >>> prim.get_measured_joint_forces() [[ 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00] [ 1.4995076e+02 4.2574748e-06 5.6364370e-04 4.8701895e-05 -6.9072924e+00 3.1881387e-05] [-2.8971717e-05 -1.0677823e+02 -6.8384506e+01 -6.9072924e+00 -5.4927128e-05 6.1222494e-07] [ 8.7120995e+01 -4.3871860e-05 -5.5795174e+01 5.3687054e-05 -2.4538563e+01 1.3333466e-05] [ 5.3519474e-05 -4.8109909e+01 6.0709282e+01 1.9157074e+01 -5.9258469e-05 8.2744418e-07] [-3.1691040e+01 2.3313689e-04 3.9990173e+01 -5.8968733e-05 -1.1863431e+00 2.2335558e-05] [-1.0809851e-04 1.5340537e+01 -1.5458489e+01 1.1863426e+00 6.1094368e-05 -1.5940281e-05] [-7.5418940e+00 -5.0814648e+00 -5.6512990e+00 -5.6385466e-05 3.8859999e-01 -3.4943256e-01] [ 4.7421460e+00 -3.1945827e+00 3.5528181e+00 5.5852943e-05 8.4794536e-03 7.6405057e-03] [ 4.0760727e+00 2.1640673e-01 -4.0513167e+00 -5.9565349e-04 1.1407082e-02 2.1432268e-06] [ 5.1680198e-03 -9.7754575e-02 -9.7093947e-02 -8.4155556e-12 -1.2910691e-12 -1.9347857e-11] [-5.1910793e-03 9.7588278e-02 -9.7106412e-02 8.4155573e-12 1.2910637e-12 -1.9347855e-11]] >>> >>> # get measured joint force and torque for the fingers >>> metadata = prim._articulation_view._metadata >>> joint_indices = 1 + np.array([ ... metadata.joint_indices["panda_finger_joint1"], ... metadata.joint_indices["panda_finger_joint2"], ... ]) >>> joint_indices [10 11] >>> prim.get_measured_joint_forces(joint_indices) [[ 5.1680198e-03 -9.7754575e-02 -9.7093947e-02 -8.4155556e-12 -1.2910691e-12 -1.9347857e-11] [-5.1910793e-03 9.7588278e-02 -9.7106412e-02 8.4155573e-12 1.2910637e-12 -1.9347855e-11]]
- get_sleep_threshold() float
Get the threshold for articulations to enter a sleep state
Search for Articulations and Sleeping in PhysX docs for more details
- Returns
sleep threshold
- Return type
float
Example:
>>> prim.get_sleep_threshold() 0.005
- get_solver_position_iteration_count() int
Get the solver (position) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
- Returns
position iteration count
- Return type
int
Example:
>>> prim.get_solver_position_iteration_count() 32
- get_solver_velocity_iteration_count() int
Get the solver (velocity) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
- Returns
velocity iteration count
- Return type
int
Example:
>>> prim.get_solver_velocity_iteration_count() 32
- get_stabilization_threshold() float
Get the mass-normalized kinetic energy below which the articulation may participate in stabilization
Search for Stabilization Threshold in PhysX docs for more details
- Returns
stabilization threshold
- Return type
float
Example:
>>> prim.get_stabilization_threshold() 0.0009999999
- get_visibility() bool
- Returns
true if the prim is visible in stage. false otherwise.
- Return type
bool
Example:
>>> # get the visible state of an visible prim on the stage >>> prim.get_visibility() True
- get_world_pose() Tuple[numpy.ndarray, numpy.ndarray]
Get prim’s pose with respect to the world’s frame
- Returns
first index is the position in the world frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the world frame
- Return type
Tuple[np.ndarray, np.ndarray]
Example:
>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame >>> position, orientation = prim.get_world_pose() >>> position [1. 0.5 0. ] >>> orientation [1. 0. 0. 0.]
- get_world_scale() numpy.ndarray
Get prim’s scale with respect to the world’s frame
- Returns
scale applied to the prim’s dimensions in the world frame. shape is (3, ).
- Return type
np.ndarray
Example:
>>> prim.get_world_scale() [1. 1. 1.]
- property handles_initialized: bool
Check if articulation handler is initialized
- Returns
whether the handler was initialized
- Return type
bool
Example:
>>> prim.handles_initialized True
- initialize(physics_sim_view=None) None
[summary]
initialize the dc interface, set up drive mode
- is_valid() bool
Check if the prim path has a valid USD Prim at it
- Returns
True is the current prim path corresponds to a valid prim in stage. False otherwise.
- Return type
bool
Example:
>>> # given an existing and valid prim >>> prims.is_valid() True
- is_visual_material_applied() bool
Check if there is a visual material applied
- Returns
True if there is a visual material applied. False otherwise.
- Return type
bool
Example:
>>> # given a visual material applied >>> prim.is_visual_material_applied() True
- property name: Optional[str]
Returns: str: name given to the prim when instantiating it. Otherwise None.
- property non_root_articulation_link: bool
Used to query if the prim is a non root articulation link
- Returns
True if the prim itself is a non root link
- Return type
bool
Example:
>>> # for a wrapped articulation (where the root prim has the Physics Articulation Root property applied) >>> prim.non_root_articulation_link False
- property num_dof: int
Number of DOF of the articulation
- Returns
amount of DOFs
- Return type
int
Example:
>>> prim.num_dof 9
- post_reset() None
[summary]
post reset articulation
- property prim: pxr.Usd.Prim
Returns: Usd.Prim: USD Prim object that this object holds.
- property prim_path: str
Returns: str: prim path in the stage
- set_angular_velocity(velocity: numpy.ndarray) None
Set the angular velocity of the root articulation prim
Warning
This method will immediately set the articulation state
- Parameters
velocity (np.ndarray) – 3D angular velocity vector. Shape (3,)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> prim.set_angular_velocity(np.array([0.1, 0.0, 0.0]))
- set_default_state(position: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Set the default state of the prim (position and orientation), that will be used after each reset.
- Parameters
position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Example:
>>> # configure default state >>> prim.set_default_state(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1, 0, 0, 0])) >>> >>> # set default states during post-reset >>> prim.post_reset()
- set_enabled_self_collisions(flag: bool) None
Set the enable self collisions flag (
physxArticulation:enabledSelfCollisions)- Parameters
flag (bool) – whether to enable self collisions
Example:
>>> prim.set_enabled_self_collisions(True)
- set_joint_efforts(efforts: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint efforts
Note
This method can be used for effort control. For this purpose, there must be no joint drive or the stiffness and damping must be set to zero.
- Parameters
efforts (np.ndarray) – articulation joint efforts
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joint efforts to 0.0 >>> prim.set_joint_efforts(np.array([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0])) >>> >>> # set only the fingers efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 10 >>> prim.set_joint_efforts(np.array([10, 10]), joint_indices=np.array([7, 8]))
- set_joint_positions(positions: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint positions
Warning
This method will immediately set (teleport) the affected joints to the indicated value. Use the
apply_actionmethod to control robot joints.- Parameters
positions (np.ndarray) – articulation joint positions
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joints >>> prim.set_joint_positions(np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04])) >>> >>> # set only the fingers in closed position: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 0.0 >>> prim.set_joint_positions(np.array([0.04, 0.04]), joint_indices=np.array([7, 8]))
- set_joint_velocities(velocities: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint velocities
Warning
This method will immediately set the affected joints to the indicated value. Use the
apply_actionmethod to control robot joints.- Parameters
velocities (np.ndarray) – articulation joint velocities
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joint velocities to 0.0 >>> prim.set_joint_velocities(np.array([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0])) >>> >>> # set only the fingers velocities: panda_finger_joint1 (7) and panda_finger_joint2 (8) to -0.01 >>> prim.set_joint_velocities(np.array([-0.01, -0.01]), joint_indices=np.array([7, 8]))
- set_joints_default_state(positions: Optional[numpy.ndarray] = None, velocities: Optional[numpy.ndarray] = None, efforts: Optional[numpy.ndarray] = None) None
Set the joint default states (positions, velocities and/or efforts) to be applied after each reset.
Note
The default states will be set during post-reset (e.g., calling
.post_reset()orworld.reset()methods)- Parameters
positions (Optional[np.ndarray], optional) – joint positions. Defaults to None.
velocities (Optional[np.ndarray], optional) – joint velocities. Defaults to None.
efforts (Optional[np.ndarray], optional) – joint efforts. Defaults to None.
Example:
>>> # configure default joint states >>> prim.set_joints_default_state( ... positions=np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04]), ... velocities=np.zeros(shape=(prim.num_dof,)), ... efforts=np.zeros(shape=(prim.num_dof,)) ... ) >>> >>> # set default states during post-reset >>> prim.post_reset()
- set_linear_velocity(velocity: numpy.ndarray) None
Set the linear velocity of the root articulation prim
Warning
This method will immediately set the articulation state
- Parameters
velocity (np.ndarray) – 3D linear velocity vector. Shape (3,).
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> prim.set_linear_velocity(np.array([0.1, 0.0, 0.0]))
- set_local_pose(translation: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Set prim’s pose with respect to the local frame (the prim’s parent frame).
Warning
This method will change (teleport) the prim pose immediately to the indicated value
- Parameters
translation (Optional[Sequence[float]], optional) – translation in the local frame of the prim (with respect to its parent prim). shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the local frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Hint
This method belongs to the methods used to set the prim state
Example:
>>> prim.set_local_pose(translation=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))
- set_local_scale(scale: Optional[Sequence[float]]) None
Set prim’s scale with respect to the local frame (the prim’s parent frame).
- Parameters
scale (Optional[Sequence[float]]) – scale to be applied to the prim’s dimensions. shape is (3, ). Defaults to None, which means left unchanged.
Example:
>>> # scale prim 10 times smaller >>> prim.set_local_scale(np.array([0.1, 0.1, 0.1]))
- set_sleep_threshold(threshold: float) None
Set the threshold for articulations to enter a sleep state
Search for Articulations and Sleeping in PhysX docs for more details
- Parameters
threshold (float) – sleep threshold
Example:
>>> prim.set_sleep_threshold(0.01)
- set_solver_position_iteration_count(count: int) None
Set the solver (position) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
Warning
Setting a higher number of iterations may improve the fidelity of the simulation, although it may affect its performance.
- Parameters
count (int) – position iteration count
Example:
>>> prim.set_solver_position_iteration_count(64)
- set_solver_velocity_iteration_count(count: int)
Set the solver (velocity) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
Warning
Setting a higher number of iterations may improve the fidelity of the simulation, although it may affect its performance.
- Parameters
count (int) – velocity iteration count
Example:
>>> prim.set_solver_velocity_iteration_count(64)
- set_stabilization_threshold(threshold: float) None
Set the mass-normalized kinetic energy below which the articulation may participate in stabilization
Search for Stabilization Threshold in PhysX docs for more details
- Parameters
threshold (float) – stabilization threshold
Example:
>>> prim.set_stabilization_threshold(0.005)
- set_visibility(visible: bool) None
Set the visibility of the prim in stage
- Parameters
visible (bool) – flag to set the visibility of the usd prim in stage.
Example:
>>> # make prim not visible in the stage >>> prim.set_visibility(visible=False)
- set_world_pose(position: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Ses prim’s pose with respect to the world’s frame
Warning
This method will change (teleport) the prim pose immediately to the indicated value
- Parameters
position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Hint
This method belongs to the methods used to set the prim state
Example:
>>> prim.set_world_pose(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))
- class Unitree(prim_path: str, name: str = 'unitree_quadruped', physics_dt: Optional[float] = 0.0025, usd_path: Optional[str] = None, position: Optional[numpy.ndarray] = None, orientation: Optional[numpy.ndarray] = None, model: Optional[str] = 'A1', way_points: Optional[numpy.ndarray] = None)
For unitree based quadrupeds (A1 or Go1)
- advance(dt, goal, path_follow=False, auto_start=True) numpy.ndarray
[summary]
compute desired torque and set articulation effort to robot joints
Argument: dt {float} – Timestep update in the world. goal {List[int]} – x velocity, y velocity, angular velocity, state switch path_follow {bool} – true for following coordinates, false for keyboard control auto_start {bool} – true for start trotting after 1 sec, false for start trotting after switch mode function is called
Returns: np.ndarray – The desired joint torques for the robot.
- apply_action(control_actions: omni.isaac.core.utils.types.ArticulationAction) None
Apply joint positions, velocities and/or efforts to control an articulation
- Parameters
control_actions (ArticulationAction) – actions to be applied for next physics step.
indices (Optional[Union[list, np.ndarray]], optional) – degree of freedom indices to apply actions to. Defaults to all degrees of freedom.
Hint
High stiffness makes the joints snap faster and harder to the desired target, and higher damping smoothes but also slows down the joint’s movement to target
For position control, set relatively high stiffness and low damping (to reduce vibrations)
For velocity control, stiffness must be set to zero with a non-zero damping
For effort control, stiffness and damping must be set to zero
Example:
>>> from omni.isaac.core.utils.types import ArticulationAction >>> >>> # move all the robot joints to the indicated position >>> action = ArticulationAction(joint_positions=np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04])) >>> prim.apply_action(action) >>> >>> # close the robot fingers: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 0.0 >>> action = ArticulationAction(joint_positions=np.array([0.0, 0.0]), joint_indices=np.array([7, 8])) >>> prim.apply_action(action)
- apply_visual_material(visual_material: omni.isaac.core.materials.visual_material.VisualMaterial, weaker_than_descendants: bool = False) None
Apply visual material to the held prim and optionally its descendants.
- Parameters
visual_material (VisualMaterial) – visual material to be applied to the held prim. Currently supports PreviewSurface, OmniPBR and OmniGlass.
weaker_than_descendants (bool, optional) – True if the material shouldn’t override the descendants materials, otherwise False. Defaults to False.
Example:
>>> from omni.isaac.core.materials import OmniGlass >>> >>> # create a dark-red glass visual material >>> material = OmniGlass( ... prim_path="/World/material/glass", # path to the material prim to create ... ior=1.25, ... depth=0.001, ... thin_walled=False, ... color=np.array([0.5, 0.0, 0.0]) ... ) >>> prim.apply_visual_material(material)
- property articulation_handle: int
A handler to the articulation
The handler is a unique identifier used by the Dynamic Control extension to manage the articulation
- Returns
handle
- Return type
int
Example:
>>> prim.articulation_handle 1116691496961
- disable_gravity() None
Keep gravity from affecting the robot
Example:
>>> prim.disable_gravity()
- property dof_names: List[str]
List of prim names for each DOF.
- Returns
prim names
- Return type
list(string)
Example:
>>> prim.dof_names ['panda_joint1', 'panda_joint2', 'panda_joint3', 'panda_joint4', 'panda_joint5', 'panda_joint6', 'panda_joint7', 'panda_finger_joint1', 'panda_finger_joint2']
- property dof_properties: numpy.ndarray
Articulation DOF properties
DOF properties Index
Property name
Description
0
typeDOF type: invalid/unknown/uninitialized (0), rotation (1), translation (2)
1
hasLimitsWhether the DOF has limits
2
lowerLower DOF limit (in radians or meters)
3
upperUpper DOF limit (in radians or meters)
4
driveModeDrive mode for the DOF: force (1), acceleration (2)
5
maxVelocityMaximum DOF velocity. In radians/s, or stage_units/s
6
maxEffortMaximum DOF effort. In N or N*stage_units
7
stiffnessDOF stiffness
8
dampingDOF damping
- Returns
named NumPy array of shape (num_dof, 9)
- Return type
np.ndarray
Example:
>>> # get properties for all DOFs >>> prim.dof_properties [(1, True, -2.8973, 2.8973, 1, 1.0000000e+01, 5220., 60000., 3000.) (1, True, -1.7628, 1.7628, 1, 1.0000000e+01, 5220., 60000., 3000.) (1, True, -2.8973, 2.8973, 1, 5.9390470e+36, 5220., 60000., 3000.) (1, True, -3.0718, -0.0698, 1, 5.9390470e+36, 5220., 60000., 3000.) (1, True, -2.8973, 2.8973, 1, 5.9390470e+36, 720., 25000., 3000.) (1, True, -0.0175, 3.7525, 1, 5.9390470e+36, 720., 15000., 3000.) (1, True, -2.8973, 2.8973, 1, 1.0000000e+01, 720., 5000., 3000.) (2, True, 0. , 0.04 , 1, 3.4028235e+38, 720., 6000., 1000.) (2, True, 0. , 0.04 , 1, 3.4028235e+38, 720., 6000., 1000.)] >>> >>> # property names >>> prim.dof_properties.dtype.names ('type', 'hasLimits', 'lower', 'upper', 'driveMode', 'maxVelocity', 'maxEffort', 'stiffness', 'damping') >>> >>> # get DOF upper limits >>> prim.dof_properties["upper"] [ 2.8973 1.7628 2.8973 -0.0698 2.8973 3.7525 2.8973 0.04 0.04 ] >>> >>> # get the last DOF (panda_finger_joint2) upper limit >>> prim.dof_properties["upper"][8] # or prim.dof_properties[8][3] 0.04
- enable_gravity() None
Gravity will affect the robot
Example:
>>> prim.enable_gravity()
- get_angular_velocity() numpy.ndarray
Get the angular velocity of the root articulation prim
- Returns
3D angular velocity vector. Shape (3,)
- Return type
np.ndarray
Example:
>>> prim.get_angular_velocity() [0. 0. 0.]
- get_applied_action() omni.isaac.core.utils.types.ArticulationAction
Get the last applied action
- Returns
last applied action. Note: a dictionary is used as the object’s string representation
- Return type
Example:
>>> # last applied action: joint_positions -> [0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04] >>> prim.get_applied_action() {'joint_positions': [0.0, -1.0, 0.0, -2.200000047683716, 0.0, 2.4000000953674316, 0.800000011920929, 0.03999999910593033, 0.03999999910593033], 'joint_velocities': [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0], 'joint_efforts': [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]}
- get_applied_joint_efforts(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the efforts applied to the joints set by the
set_joint_effortsmethod- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
all or selected articulation joint applied efforts
- Return type
np.ndarray
Example:
>>> # get all applied joint efforts >>> prim.get_applied_joint_efforts() [ 0. 0. 0. 0. 0. 0. 0. 0. 0.] >>> >>> # get finger applied efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_applied_joint_efforts(joint_indices=np.array([7, 8])) [0. 0.]
- get_applied_visual_material() omni.isaac.core.materials.visual_material.VisualMaterial
Return the current applied visual material in case it was applied using apply_visual_material or it’s one of the following materials that was already applied before: PreviewSurface, OmniPBR and OmniGlass.
- Returns
the current applied visual material if its type is currently supported.
- Return type
Example:
>>> # given a visual material applied >>> prim.get_applied_visual_material() <omni.isaac.core.materials.omni_glass.OmniGlass object at 0x7f36263106a0>
- get_articulation_body_count() int
Get the number of bodies (links) that make up the articulation
- Returns
amount of bodies
- Return type
int
Example:
>>> prim.get_articulation_body_count() 12
- get_articulation_controller() omni.isaac.core.controllers.articulation_controller.ArticulationController
Get the articulation controller
Note
If no
articulation_controllerwas passed during class instantiation, a default controller of typeArticulationController(a Proportional-Derivative controller that can apply position targets, velocity targets and efforts) will be used- Returns
articulation controller
- Return type
Example:
>>> prim.get_articulation_controller() <omni.isaac.core.controllers.articulation_controller.ArticulationController object at 0x7f04a0060190>
- get_default_state() omni.isaac.core.utils.types.XFormPrimState
Get the default prim states (spatial position and orientation).
- Returns
an object that contains the default state of the prim (position and orientation)
- Return type
Example:
>>> state = prim.get_default_state() >>> state <omni.isaac.core.utils.types.XFormPrimState object at 0x7f33addda650> >>> >>> state.position [-4.5299529e-08 -1.8347054e-09 -2.8610229e-08] >>> state.orientation [1. 0. 0. 0.]
- get_dof_index(dof_name: str) int
Get a DOF index given its name
- Parameters
dof_name (str) – name of the DOF
- Returns
DOF index
- Return type
int
Example:
>>> prim.get_dof_index("panda_finger_joint2") 8
- get_enabled_self_collisions() int
Get the enable self collisions flag (
physxArticulation:enabledSelfCollisions)- Returns
self collisions flag (boolean interpreted as int)
- Return type
int
Example:
>>> prim.get_enabled_self_collisions() 0
- get_joint_positions(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the articulation joint positions
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Returns
all or selected articulation joint positions
- Return type
np.ndarray
Example:
>>> # get all joint positions >>> prim.get_joint_positions() [ 1.1999920e-02 -5.6962633e-01 1.3480479e-08 -2.8105433e+00 6.8284894e-06 3.0301569e+00 7.3234749e-01 3.9912373e-02 3.9999999e-02] >>> >>> # get finger positions: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_joint_positions(joint_indices=np.array([7, 8])) [0.03991237 3.9999999e-02]
- get_joint_velocities(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the articulation joint velocities
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Returns
all or selected articulation joint velocities
- Return type
np.ndarray
Example:
>>> # get all joint velocities >>> prim.get_joint_velocities() [ 1.91603772e-06 -7.67638255e-03 -2.19138826e-07 1.10636465e-02 -4.63412944e-05 3.48245539e-02 8.84692147e-02 5.40335372e-04 1.02849208e-05] >>> >>> # get finger velocities: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_joint_velocities(joint_indices=np.array([7, 8])) [5.4033537e-04 1.0284921e-05]
- get_joints_default_state() omni.isaac.core.utils.types.JointsState
Get the default joint states (positions and velocities).
- Returns
an object that contains the default joint positions and velocities
- Return type
Example:
>>> state = prim.get_joints_default_state() >>> state <omni.isaac.core.utils.types.JointsState object at 0x7f04a0061240> >>> >>> state.positions [ 0.012 -0.57000005 0. -2.81 0. 3.037 0.785398 0.04 0.04 ] >>> state.velocities [0. 0. 0. 0. 0. 0. 0. 0. 0.]
- get_joints_state() omni.isaac.core.utils.types.JointsState
Get the current joint states (positions and velocities)
- Returns
an object that contains the current joint positions and velocities
- Return type
Example:
>>> state = prim.get_joints_state() >>> state <omni.isaac.core.utils.types.JointsState object at 0x7f02f6df57b0> >>> >>> state.positions [ 1.1999920e-02 -5.6962633e-01 1.3480479e-08 -2.8105433e+00 6.8284894e-06 3.0301569e+00 7.3234749e-01 3.9912373e-02 3.9999999e-02] >>> state.velocities [ 1.91603772e-06 -7.67638255e-03 -2.19138826e-07 1.10636465e-02 -4.63412944e-05 245539e-02 8.84692147e-02 5.40335372e-04 1.02849208e-05]
- get_linear_velocity() numpy.ndarray
Get the linear velocity of the root articulation prim
- Returns
3D linear velocity vector. Shape (3,)
- Return type
np.ndarray
Example:
>>> prim.get_linear_velocity() [0. 0. 0.]
- get_local_pose() Tuple[numpy.ndarray, numpy.ndarray]
Get prim’s pose with respect to the local frame (the prim’s parent frame)
- Returns
first index is the position in the local frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the local frame
- Return type
Tuple[np.ndarray, np.ndarray]
Example:
>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame >>> position, orientation = prim.get_local_pose() >>> position [0. 0. 0.] >>> orientation [0. 0. 0.]
- get_local_scale() numpy.ndarray
Get prim’s scale with respect to the local frame (the parent’s frame)
- Returns
scale applied to the prim’s dimensions in the local frame. shape is (3, ).
- Return type
np.ndarray
Example:
>>> prim.get_local_scale() [1. 1. 1.]
- get_measured_joint_efforts(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Returns the efforts computed/measured by the physics solver of the joint forces in the DOF motion direction
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
all or selected articulation joint measured efforts
- Return type
np.ndarray
Example:
>>> # get all joint efforts >>> prim.get_measured_joint_efforts() [ 2.7897308e-06 -6.9083519e+00 -3.6398471e-06 1.9158335e+01 -4.3552645e-06 1.1866090e+00 -4.7079347e-06 3.2339853e-04 -3.2044132e-04] >>> >>> # get finger efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_measured_joint_efforts(joint_indices=np.array([7, 8])) [ 0.0003234 -0.00032044]
- get_measured_joint_forces(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the measured joint reaction forces and torques (link incoming joint forces and torques) to external loads
Note
Since the name->index map for joints has not been exposed yet, it is possible to access the joint names and their indices through the articulation metadata.
prim._articulation_view._metadata.joint_names # list of names prim._articulation_view._metadata.joint_indices # dict of name: index
To retrieve a specific row for the link incoming joint force/torque use
joint_index + 1- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
measured joint forces and torques. Shape is (num_joint + 1, 6). Row index 0 is the incoming joint of the base link. For the last dimension the first 3 values are for forces and the last 3 for torques
- Return type
np.ndarray
Example:
>>> # get all measured joint forces and torques >>> prim.get_measured_joint_forces() [[ 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00] [ 1.4995076e+02 4.2574748e-06 5.6364370e-04 4.8701895e-05 -6.9072924e+00 3.1881387e-05] [-2.8971717e-05 -1.0677823e+02 -6.8384506e+01 -6.9072924e+00 -5.4927128e-05 6.1222494e-07] [ 8.7120995e+01 -4.3871860e-05 -5.5795174e+01 5.3687054e-05 -2.4538563e+01 1.3333466e-05] [ 5.3519474e-05 -4.8109909e+01 6.0709282e+01 1.9157074e+01 -5.9258469e-05 8.2744418e-07] [-3.1691040e+01 2.3313689e-04 3.9990173e+01 -5.8968733e-05 -1.1863431e+00 2.2335558e-05] [-1.0809851e-04 1.5340537e+01 -1.5458489e+01 1.1863426e+00 6.1094368e-05 -1.5940281e-05] [-7.5418940e+00 -5.0814648e+00 -5.6512990e+00 -5.6385466e-05 3.8859999e-01 -3.4943256e-01] [ 4.7421460e+00 -3.1945827e+00 3.5528181e+00 5.5852943e-05 8.4794536e-03 7.6405057e-03] [ 4.0760727e+00 2.1640673e-01 -4.0513167e+00 -5.9565349e-04 1.1407082e-02 2.1432268e-06] [ 5.1680198e-03 -9.7754575e-02 -9.7093947e-02 -8.4155556e-12 -1.2910691e-12 -1.9347857e-11] [-5.1910793e-03 9.7588278e-02 -9.7106412e-02 8.4155573e-12 1.2910637e-12 -1.9347855e-11]] >>> >>> # get measured joint force and torque for the fingers >>> metadata = prim._articulation_view._metadata >>> joint_indices = 1 + np.array([ ... metadata.joint_indices["panda_finger_joint1"], ... metadata.joint_indices["panda_finger_joint2"], ... ]) >>> joint_indices [10 11] >>> prim.get_measured_joint_forces(joint_indices) [[ 5.1680198e-03 -9.7754575e-02 -9.7093947e-02 -8.4155556e-12 -1.2910691e-12 -1.9347857e-11] [-5.1910793e-03 9.7588278e-02 -9.7106412e-02 8.4155573e-12 1.2910637e-12 -1.9347855e-11]]
- get_sleep_threshold() float
Get the threshold for articulations to enter a sleep state
Search for Articulations and Sleeping in PhysX docs for more details
- Returns
sleep threshold
- Return type
float
Example:
>>> prim.get_sleep_threshold() 0.005
- get_solver_position_iteration_count() int
Get the solver (position) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
- Returns
position iteration count
- Return type
int
Example:
>>> prim.get_solver_position_iteration_count() 32
- get_solver_velocity_iteration_count() int
Get the solver (velocity) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
- Returns
velocity iteration count
- Return type
int
Example:
>>> prim.get_solver_velocity_iteration_count() 32
- get_stabilization_threshold() float
Get the mass-normalized kinetic energy below which the articulation may participate in stabilization
Search for Stabilization Threshold in PhysX docs for more details
- Returns
stabilization threshold
- Return type
float
Example:
>>> prim.get_stabilization_threshold() 0.0009999999
- get_visibility() bool
- Returns
true if the prim is visible in stage. false otherwise.
- Return type
bool
Example:
>>> # get the visible state of an visible prim on the stage >>> prim.get_visibility() True
- get_world_pose() Tuple[numpy.ndarray, numpy.ndarray]
Get prim’s pose with respect to the world’s frame
- Returns
first index is the position in the world frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the world frame
- Return type
Tuple[np.ndarray, np.ndarray]
Example:
>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame >>> position, orientation = prim.get_world_pose() >>> position [1. 0.5 0. ] >>> orientation [1. 0. 0. 0.]
- get_world_scale() numpy.ndarray
Get prim’s scale with respect to the world’s frame
- Returns
scale applied to the prim’s dimensions in the world frame. shape is (3, ).
- Return type
np.ndarray
Example:
>>> prim.get_world_scale() [1. 1. 1.]
- property handles_initialized: bool
Check if articulation handler is initialized
- Returns
whether the handler was initialized
- Return type
bool
Example:
>>> prim.handles_initialized True
- initialize(physics_sim_view=None) None
[summary]
initialize dc interface, set up drive mode and initial robot state
- is_valid() bool
Check if the prim path has a valid USD Prim at it
- Returns
True is the current prim path corresponds to a valid prim in stage. False otherwise.
- Return type
bool
Example:
>>> # given an existing and valid prim >>> prims.is_valid() True
- is_visual_material_applied() bool
Check if there is a visual material applied
- Returns
True if there is a visual material applied. False otherwise.
- Return type
bool
Example:
>>> # given a visual material applied >>> prim.is_visual_material_applied() True
- property name: Optional[str]
Returns: str: name given to the prim when instantiating it. Otherwise None.
- property non_root_articulation_link: bool
Used to query if the prim is a non root articulation link
- Returns
True if the prim itself is a non root link
- Return type
bool
Example:
>>> # for a wrapped articulation (where the root prim has the Physics Articulation Root property applied) >>> prim.non_root_articulation_link False
- property num_dof: int
Number of DOF of the articulation
- Returns
amount of DOFs
- Return type
int
Example:
>>> prim.num_dof 9
- post_reset() None
[summary]
post reset articulation and qp_controller
- property prim: pxr.Usd.Prim
Returns: Usd.Prim: USD Prim object that this object holds.
- property prim_path: str
Returns: str: prim path in the stage
- set_angular_velocity(velocity: numpy.ndarray) None
Set the angular velocity of the root articulation prim
Warning
This method will immediately set the articulation state
- Parameters
velocity (np.ndarray) – 3D angular velocity vector. Shape (3,)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> prim.set_angular_velocity(np.array([0.1, 0.0, 0.0]))
- set_default_state(position: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Set the default state of the prim (position and orientation), that will be used after each reset.
- Parameters
position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Example:
>>> # configure default state >>> prim.set_default_state(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1, 0, 0, 0])) >>> >>> # set default states during post-reset >>> prim.post_reset()
- set_enabled_self_collisions(flag: bool) None
Set the enable self collisions flag (
physxArticulation:enabledSelfCollisions)- Parameters
flag (bool) – whether to enable self collisions
Example:
>>> prim.set_enabled_self_collisions(True)
- set_joint_efforts(efforts: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint efforts
Note
This method can be used for effort control. For this purpose, there must be no joint drive or the stiffness and damping must be set to zero.
- Parameters
efforts (np.ndarray) – articulation joint efforts
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joint efforts to 0.0 >>> prim.set_joint_efforts(np.array([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0])) >>> >>> # set only the fingers efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 10 >>> prim.set_joint_efforts(np.array([10, 10]), joint_indices=np.array([7, 8]))
- set_joint_positions(positions: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint positions
Warning
This method will immediately set (teleport) the affected joints to the indicated value. Use the
apply_actionmethod to control robot joints.- Parameters
positions (np.ndarray) – articulation joint positions
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joints >>> prim.set_joint_positions(np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04])) >>> >>> # set only the fingers in closed position: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 0.0 >>> prim.set_joint_positions(np.array([0.04, 0.04]), joint_indices=np.array([7, 8]))
- set_joint_velocities(velocities: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint velocities
Warning
This method will immediately set the affected joints to the indicated value. Use the
apply_actionmethod to control robot joints.- Parameters
velocities (np.ndarray) – articulation joint velocities
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joint velocities to 0.0 >>> prim.set_joint_velocities(np.array([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0])) >>> >>> # set only the fingers velocities: panda_finger_joint1 (7) and panda_finger_joint2 (8) to -0.01 >>> prim.set_joint_velocities(np.array([-0.01, -0.01]), joint_indices=np.array([7, 8]))
- set_joints_default_state(positions: Optional[numpy.ndarray] = None, velocities: Optional[numpy.ndarray] = None, efforts: Optional[numpy.ndarray] = None) None
Set the joint default states (positions, velocities and/or efforts) to be applied after each reset.
Note
The default states will be set during post-reset (e.g., calling
.post_reset()orworld.reset()methods)- Parameters
positions (Optional[np.ndarray], optional) – joint positions. Defaults to None.
velocities (Optional[np.ndarray], optional) – joint velocities. Defaults to None.
efforts (Optional[np.ndarray], optional) – joint efforts. Defaults to None.
Example:
>>> # configure default joint states >>> prim.set_joints_default_state( ... positions=np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04]), ... velocities=np.zeros(shape=(prim.num_dof,)), ... efforts=np.zeros(shape=(prim.num_dof,)) ... ) >>> >>> # set default states during post-reset >>> prim.post_reset()
- set_linear_velocity(velocity: numpy.ndarray) None
Set the linear velocity of the root articulation prim
Warning
This method will immediately set the articulation state
- Parameters
velocity (np.ndarray) – 3D linear velocity vector. Shape (3,).
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> prim.set_linear_velocity(np.array([0.1, 0.0, 0.0]))
- set_local_pose(translation: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Set prim’s pose with respect to the local frame (the prim’s parent frame).
Warning
This method will change (teleport) the prim pose immediately to the indicated value
- Parameters
translation (Optional[Sequence[float]], optional) – translation in the local frame of the prim (with respect to its parent prim). shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the local frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Hint
This method belongs to the methods used to set the prim state
Example:
>>> prim.set_local_pose(translation=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))
- set_local_scale(scale: Optional[Sequence[float]]) None
Set prim’s scale with respect to the local frame (the prim’s parent frame).
- Parameters
scale (Optional[Sequence[float]]) – scale to be applied to the prim’s dimensions. shape is (3, ). Defaults to None, which means left unchanged.
Example:
>>> # scale prim 10 times smaller >>> prim.set_local_scale(np.array([0.1, 0.1, 0.1]))
- set_sleep_threshold(threshold: float) None
Set the threshold for articulations to enter a sleep state
Search for Articulations and Sleeping in PhysX docs for more details
- Parameters
threshold (float) – sleep threshold
Example:
>>> prim.set_sleep_threshold(0.01)
- set_solver_position_iteration_count(count: int) None
Set the solver (position) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
Warning
Setting a higher number of iterations may improve the fidelity of the simulation, although it may affect its performance.
- Parameters
count (int) – position iteration count
Example:
>>> prim.set_solver_position_iteration_count(64)
- set_solver_velocity_iteration_count(count: int)
Set the solver (velocity) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
Warning
Setting a higher number of iterations may improve the fidelity of the simulation, although it may affect its performance.
- Parameters
count (int) – velocity iteration count
Example:
>>> prim.set_solver_velocity_iteration_count(64)
- set_stabilization_threshold(threshold: float) None
Set the mass-normalized kinetic energy below which the articulation may participate in stabilization
Search for Stabilization Threshold in PhysX docs for more details
- Parameters
threshold (float) – stabilization threshold
Example:
>>> prim.set_stabilization_threshold(0.005)
- set_state(state: omni.isaac.quadruped.utils.a1_classes.A1State) None
[Summary]
Set the kinematic state of the robot.
- Parameters
set. (state {A1State} -- The state of the robot to) –
- Raises
RuntimeError – When the DC Toolbox interface has not been configured.
- set_visibility(visible: bool) None
Set the visibility of the prim in stage
- Parameters
visible (bool) – flag to set the visibility of the usd prim in stage.
Example:
>>> # make prim not visible in the stage >>> prim.set_visibility(visible=False)
- set_world_pose(position: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Ses prim’s pose with respect to the world’s frame
Warning
This method will change (teleport) the prim pose immediately to the indicated value
- Parameters
position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Hint
This method belongs to the methods used to set the prim state
Example:
>>> prim.set_world_pose(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))
- update() None
[summary]
update robot sensor variables, state variables in A1Measurement
- update_contact_sensor_data() None
[summary]
Updates processed contact sensor data from the robot feets, store them in member variable foot_force
- update_imu_sensor_data() None
[summary]
Updates processed imu sensor data from the robot body, store them in member variable base_lin and ang_vel
- class UnitreeDirect(prim_path: str, name: str = 'unitree_quadruped_ROS', physics_dt: Optional[float] = 0.0025, usd_path: Optional[str] = None, position: Optional[numpy.ndarray] = None, orientation: Optional[numpy.ndarray] = None, model: Optional[str] = 'A1')
For unitree based quadrupeds (A1 or Go1) This class only read command from an external torque and send the torque command to the articulation directly, perhaps a external ROS node generates the command
- advance()
[summary]
direct control the robot using desired_joint_torque
Argument: dt {float} – Timestep update in the world. goal {List[int]} – x velocity, y velocity, angular velocity, state switch
Returns: np.ndarray – The desired joint torques for the robot.
- apply_action(control_actions: omni.isaac.core.utils.types.ArticulationAction) None
Apply joint positions, velocities and/or efforts to control an articulation
- Parameters
control_actions (ArticulationAction) – actions to be applied for next physics step.
indices (Optional[Union[list, np.ndarray]], optional) – degree of freedom indices to apply actions to. Defaults to all degrees of freedom.
Hint
High stiffness makes the joints snap faster and harder to the desired target, and higher damping smoothes but also slows down the joint’s movement to target
For position control, set relatively high stiffness and low damping (to reduce vibrations)
For velocity control, stiffness must be set to zero with a non-zero damping
For effort control, stiffness and damping must be set to zero
Example:
>>> from omni.isaac.core.utils.types import ArticulationAction >>> >>> # move all the robot joints to the indicated position >>> action = ArticulationAction(joint_positions=np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04])) >>> prim.apply_action(action) >>> >>> # close the robot fingers: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 0.0 >>> action = ArticulationAction(joint_positions=np.array([0.0, 0.0]), joint_indices=np.array([7, 8])) >>> prim.apply_action(action)
- apply_visual_material(visual_material: omni.isaac.core.materials.visual_material.VisualMaterial, weaker_than_descendants: bool = False) None
Apply visual material to the held prim and optionally its descendants.
- Parameters
visual_material (VisualMaterial) – visual material to be applied to the held prim. Currently supports PreviewSurface, OmniPBR and OmniGlass.
weaker_than_descendants (bool, optional) – True if the material shouldn’t override the descendants materials, otherwise False. Defaults to False.
Example:
>>> from omni.isaac.core.materials import OmniGlass >>> >>> # create a dark-red glass visual material >>> material = OmniGlass( ... prim_path="/World/material/glass", # path to the material prim to create ... ior=1.25, ... depth=0.001, ... thin_walled=False, ... color=np.array([0.5, 0.0, 0.0]) ... ) >>> prim.apply_visual_material(material)
- property articulation_handle: int
A handler to the articulation
The handler is a unique identifier used by the Dynamic Control extension to manage the articulation
- Returns
handle
- Return type
int
Example:
>>> prim.articulation_handle 1116691496961
- disable_gravity() None
Keep gravity from affecting the robot
Example:
>>> prim.disable_gravity()
- property dof_names: List[str]
List of prim names for each DOF.
- Returns
prim names
- Return type
list(string)
Example:
>>> prim.dof_names ['panda_joint1', 'panda_joint2', 'panda_joint3', 'panda_joint4', 'panda_joint5', 'panda_joint6', 'panda_joint7', 'panda_finger_joint1', 'panda_finger_joint2']
- property dof_properties: numpy.ndarray
Articulation DOF properties
DOF properties Index
Property name
Description
0
typeDOF type: invalid/unknown/uninitialized (0), rotation (1), translation (2)
1
hasLimitsWhether the DOF has limits
2
lowerLower DOF limit (in radians or meters)
3
upperUpper DOF limit (in radians or meters)
4
driveModeDrive mode for the DOF: force (1), acceleration (2)
5
maxVelocityMaximum DOF velocity. In radians/s, or stage_units/s
6
maxEffortMaximum DOF effort. In N or N*stage_units
7
stiffnessDOF stiffness
8
dampingDOF damping
- Returns
named NumPy array of shape (num_dof, 9)
- Return type
np.ndarray
Example:
>>> # get properties for all DOFs >>> prim.dof_properties [(1, True, -2.8973, 2.8973, 1, 1.0000000e+01, 5220., 60000., 3000.) (1, True, -1.7628, 1.7628, 1, 1.0000000e+01, 5220., 60000., 3000.) (1, True, -2.8973, 2.8973, 1, 5.9390470e+36, 5220., 60000., 3000.) (1, True, -3.0718, -0.0698, 1, 5.9390470e+36, 5220., 60000., 3000.) (1, True, -2.8973, 2.8973, 1, 5.9390470e+36, 720., 25000., 3000.) (1, True, -0.0175, 3.7525, 1, 5.9390470e+36, 720., 15000., 3000.) (1, True, -2.8973, 2.8973, 1, 1.0000000e+01, 720., 5000., 3000.) (2, True, 0. , 0.04 , 1, 3.4028235e+38, 720., 6000., 1000.) (2, True, 0. , 0.04 , 1, 3.4028235e+38, 720., 6000., 1000.)] >>> >>> # property names >>> prim.dof_properties.dtype.names ('type', 'hasLimits', 'lower', 'upper', 'driveMode', 'maxVelocity', 'maxEffort', 'stiffness', 'damping') >>> >>> # get DOF upper limits >>> prim.dof_properties["upper"] [ 2.8973 1.7628 2.8973 -0.0698 2.8973 3.7525 2.8973 0.04 0.04 ] >>> >>> # get the last DOF (panda_finger_joint2) upper limit >>> prim.dof_properties["upper"][8] # or prim.dof_properties[8][3] 0.04
- enable_gravity() None
Gravity will affect the robot
Example:
>>> prim.enable_gravity()
- get_angular_velocity() numpy.ndarray
Get the angular velocity of the root articulation prim
- Returns
3D angular velocity vector. Shape (3,)
- Return type
np.ndarray
Example:
>>> prim.get_angular_velocity() [0. 0. 0.]
- get_applied_action() omni.isaac.core.utils.types.ArticulationAction
Get the last applied action
- Returns
last applied action. Note: a dictionary is used as the object’s string representation
- Return type
Example:
>>> # last applied action: joint_positions -> [0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04] >>> prim.get_applied_action() {'joint_positions': [0.0, -1.0, 0.0, -2.200000047683716, 0.0, 2.4000000953674316, 0.800000011920929, 0.03999999910593033, 0.03999999910593033], 'joint_velocities': [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0], 'joint_efforts': [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]}
- get_applied_joint_efforts(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the efforts applied to the joints set by the
set_joint_effortsmethod- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
all or selected articulation joint applied efforts
- Return type
np.ndarray
Example:
>>> # get all applied joint efforts >>> prim.get_applied_joint_efforts() [ 0. 0. 0. 0. 0. 0. 0. 0. 0.] >>> >>> # get finger applied efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_applied_joint_efforts(joint_indices=np.array([7, 8])) [0. 0.]
- get_applied_visual_material() omni.isaac.core.materials.visual_material.VisualMaterial
Return the current applied visual material in case it was applied using apply_visual_material or it’s one of the following materials that was already applied before: PreviewSurface, OmniPBR and OmniGlass.
- Returns
the current applied visual material if its type is currently supported.
- Return type
Example:
>>> # given a visual material applied >>> prim.get_applied_visual_material() <omni.isaac.core.materials.omni_glass.OmniGlass object at 0x7f36263106a0>
- get_articulation_body_count() int
Get the number of bodies (links) that make up the articulation
- Returns
amount of bodies
- Return type
int
Example:
>>> prim.get_articulation_body_count() 12
- get_articulation_controller() omni.isaac.core.controllers.articulation_controller.ArticulationController
Get the articulation controller
Note
If no
articulation_controllerwas passed during class instantiation, a default controller of typeArticulationController(a Proportional-Derivative controller that can apply position targets, velocity targets and efforts) will be used- Returns
articulation controller
- Return type
Example:
>>> prim.get_articulation_controller() <omni.isaac.core.controllers.articulation_controller.ArticulationController object at 0x7f04a0060190>
- get_default_state() omni.isaac.core.utils.types.XFormPrimState
Get the default prim states (spatial position and orientation).
- Returns
an object that contains the default state of the prim (position and orientation)
- Return type
Example:
>>> state = prim.get_default_state() >>> state <omni.isaac.core.utils.types.XFormPrimState object at 0x7f33addda650> >>> >>> state.position [-4.5299529e-08 -1.8347054e-09 -2.8610229e-08] >>> state.orientation [1. 0. 0. 0.]
- get_dof_index(dof_name: str) int
Get a DOF index given its name
- Parameters
dof_name (str) – name of the DOF
- Returns
DOF index
- Return type
int
Example:
>>> prim.get_dof_index("panda_finger_joint2") 8
- get_enabled_self_collisions() int
Get the enable self collisions flag (
physxArticulation:enabledSelfCollisions)- Returns
self collisions flag (boolean interpreted as int)
- Return type
int
Example:
>>> prim.get_enabled_self_collisions() 0
- get_joint_positions(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the articulation joint positions
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Returns
all or selected articulation joint positions
- Return type
np.ndarray
Example:
>>> # get all joint positions >>> prim.get_joint_positions() [ 1.1999920e-02 -5.6962633e-01 1.3480479e-08 -2.8105433e+00 6.8284894e-06 3.0301569e+00 7.3234749e-01 3.9912373e-02 3.9999999e-02] >>> >>> # get finger positions: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_joint_positions(joint_indices=np.array([7, 8])) [0.03991237 3.9999999e-02]
- get_joint_velocities(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the articulation joint velocities
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Returns
all or selected articulation joint velocities
- Return type
np.ndarray
Example:
>>> # get all joint velocities >>> prim.get_joint_velocities() [ 1.91603772e-06 -7.67638255e-03 -2.19138826e-07 1.10636465e-02 -4.63412944e-05 3.48245539e-02 8.84692147e-02 5.40335372e-04 1.02849208e-05] >>> >>> # get finger velocities: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_joint_velocities(joint_indices=np.array([7, 8])) [5.4033537e-04 1.0284921e-05]
- get_joints_default_state() omni.isaac.core.utils.types.JointsState
Get the default joint states (positions and velocities).
- Returns
an object that contains the default joint positions and velocities
- Return type
Example:
>>> state = prim.get_joints_default_state() >>> state <omni.isaac.core.utils.types.JointsState object at 0x7f04a0061240> >>> >>> state.positions [ 0.012 -0.57000005 0. -2.81 0. 3.037 0.785398 0.04 0.04 ] >>> state.velocities [0. 0. 0. 0. 0. 0. 0. 0. 0.]
- get_joints_state() omni.isaac.core.utils.types.JointsState
Get the current joint states (positions and velocities)
- Returns
an object that contains the current joint positions and velocities
- Return type
Example:
>>> state = prim.get_joints_state() >>> state <omni.isaac.core.utils.types.JointsState object at 0x7f02f6df57b0> >>> >>> state.positions [ 1.1999920e-02 -5.6962633e-01 1.3480479e-08 -2.8105433e+00 6.8284894e-06 3.0301569e+00 7.3234749e-01 3.9912373e-02 3.9999999e-02] >>> state.velocities [ 1.91603772e-06 -7.67638255e-03 -2.19138826e-07 1.10636465e-02 -4.63412944e-05 245539e-02 8.84692147e-02 5.40335372e-04 1.02849208e-05]
- get_linear_velocity() numpy.ndarray
Get the linear velocity of the root articulation prim
- Returns
3D linear velocity vector. Shape (3,)
- Return type
np.ndarray
Example:
>>> prim.get_linear_velocity() [0. 0. 0.]
- get_local_pose() Tuple[numpy.ndarray, numpy.ndarray]
Get prim’s pose with respect to the local frame (the prim’s parent frame)
- Returns
first index is the position in the local frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the local frame
- Return type
Tuple[np.ndarray, np.ndarray]
Example:
>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame >>> position, orientation = prim.get_local_pose() >>> position [0. 0. 0.] >>> orientation [0. 0. 0.]
- get_local_scale() numpy.ndarray
Get prim’s scale with respect to the local frame (the parent’s frame)
- Returns
scale applied to the prim’s dimensions in the local frame. shape is (3, ).
- Return type
np.ndarray
Example:
>>> prim.get_local_scale() [1. 1. 1.]
- get_measured_joint_efforts(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Returns the efforts computed/measured by the physics solver of the joint forces in the DOF motion direction
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
all or selected articulation joint measured efforts
- Return type
np.ndarray
Example:
>>> # get all joint efforts >>> prim.get_measured_joint_efforts() [ 2.7897308e-06 -6.9083519e+00 -3.6398471e-06 1.9158335e+01 -4.3552645e-06 1.1866090e+00 -4.7079347e-06 3.2339853e-04 -3.2044132e-04] >>> >>> # get finger efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_measured_joint_efforts(joint_indices=np.array([7, 8])) [ 0.0003234 -0.00032044]
- get_measured_joint_forces(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the measured joint reaction forces and torques (link incoming joint forces and torques) to external loads
Note
Since the name->index map for joints has not been exposed yet, it is possible to access the joint names and their indices through the articulation metadata.
prim._articulation_view._metadata.joint_names # list of names prim._articulation_view._metadata.joint_indices # dict of name: index
To retrieve a specific row for the link incoming joint force/torque use
joint_index + 1- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
measured joint forces and torques. Shape is (num_joint + 1, 6). Row index 0 is the incoming joint of the base link. For the last dimension the first 3 values are for forces and the last 3 for torques
- Return type
np.ndarray
Example:
>>> # get all measured joint forces and torques >>> prim.get_measured_joint_forces() [[ 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00] [ 1.4995076e+02 4.2574748e-06 5.6364370e-04 4.8701895e-05 -6.9072924e+00 3.1881387e-05] [-2.8971717e-05 -1.0677823e+02 -6.8384506e+01 -6.9072924e+00 -5.4927128e-05 6.1222494e-07] [ 8.7120995e+01 -4.3871860e-05 -5.5795174e+01 5.3687054e-05 -2.4538563e+01 1.3333466e-05] [ 5.3519474e-05 -4.8109909e+01 6.0709282e+01 1.9157074e+01 -5.9258469e-05 8.2744418e-07] [-3.1691040e+01 2.3313689e-04 3.9990173e+01 -5.8968733e-05 -1.1863431e+00 2.2335558e-05] [-1.0809851e-04 1.5340537e+01 -1.5458489e+01 1.1863426e+00 6.1094368e-05 -1.5940281e-05] [-7.5418940e+00 -5.0814648e+00 -5.6512990e+00 -5.6385466e-05 3.8859999e-01 -3.4943256e-01] [ 4.7421460e+00 -3.1945827e+00 3.5528181e+00 5.5852943e-05 8.4794536e-03 7.6405057e-03] [ 4.0760727e+00 2.1640673e-01 -4.0513167e+00 -5.9565349e-04 1.1407082e-02 2.1432268e-06] [ 5.1680198e-03 -9.7754575e-02 -9.7093947e-02 -8.4155556e-12 -1.2910691e-12 -1.9347857e-11] [-5.1910793e-03 9.7588278e-02 -9.7106412e-02 8.4155573e-12 1.2910637e-12 -1.9347855e-11]] >>> >>> # get measured joint force and torque for the fingers >>> metadata = prim._articulation_view._metadata >>> joint_indices = 1 + np.array([ ... metadata.joint_indices["panda_finger_joint1"], ... metadata.joint_indices["panda_finger_joint2"], ... ]) >>> joint_indices [10 11] >>> prim.get_measured_joint_forces(joint_indices) [[ 5.1680198e-03 -9.7754575e-02 -9.7093947e-02 -8.4155556e-12 -1.2910691e-12 -1.9347857e-11] [-5.1910793e-03 9.7588278e-02 -9.7106412e-02 8.4155573e-12 1.2910637e-12 -1.9347855e-11]]
- get_sleep_threshold() float
Get the threshold for articulations to enter a sleep state
Search for Articulations and Sleeping in PhysX docs for more details
- Returns
sleep threshold
- Return type
float
Example:
>>> prim.get_sleep_threshold() 0.005
- get_solver_position_iteration_count() int
Get the solver (position) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
- Returns
position iteration count
- Return type
int
Example:
>>> prim.get_solver_position_iteration_count() 32
- get_solver_velocity_iteration_count() int
Get the solver (velocity) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
- Returns
velocity iteration count
- Return type
int
Example:
>>> prim.get_solver_velocity_iteration_count() 32
- get_stabilization_threshold() float
Get the mass-normalized kinetic energy below which the articulation may participate in stabilization
Search for Stabilization Threshold in PhysX docs for more details
- Returns
stabilization threshold
- Return type
float
Example:
>>> prim.get_stabilization_threshold() 0.0009999999
- get_visibility() bool
- Returns
true if the prim is visible in stage. false otherwise.
- Return type
bool
Example:
>>> # get the visible state of an visible prim on the stage >>> prim.get_visibility() True
- get_world_pose() Tuple[numpy.ndarray, numpy.ndarray]
Get prim’s pose with respect to the world’s frame
- Returns
first index is the position in the world frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the world frame
- Return type
Tuple[np.ndarray, np.ndarray]
Example:
>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame >>> position, orientation = prim.get_world_pose() >>> position [1. 0.5 0. ] >>> orientation [1. 0. 0. 0.]
- get_world_scale() numpy.ndarray
Get prim’s scale with respect to the world’s frame
- Returns
scale applied to the prim’s dimensions in the world frame. shape is (3, ).
- Return type
np.ndarray
Example:
>>> prim.get_world_scale() [1. 1. 1.]
- property handles_initialized: bool
Check if articulation handler is initialized
- Returns
whether the handler was initialized
- Return type
bool
Example:
>>> prim.handles_initialized True
- initialize(physics_sim_view=None) None
[summary]
initialize dc interface, set up drive mode and initial robot state
- is_valid() bool
Check if the prim path has a valid USD Prim at it
- Returns
True is the current prim path corresponds to a valid prim in stage. False otherwise.
- Return type
bool
Example:
>>> # given an existing and valid prim >>> prims.is_valid() True
- is_visual_material_applied() bool
Check if there is a visual material applied
- Returns
True if there is a visual material applied. False otherwise.
- Return type
bool
Example:
>>> # given a visual material applied >>> prim.is_visual_material_applied() True
- property name: Optional[str]
Returns: str: name given to the prim when instantiating it. Otherwise None.
- property non_root_articulation_link: bool
Used to query if the prim is a non root articulation link
- Returns
True if the prim itself is a non root link
- Return type
bool
Example:
>>> # for a wrapped articulation (where the root prim has the Physics Articulation Root property applied) >>> prim.non_root_articulation_link False
- property num_dof: int
Number of DOF of the articulation
- Returns
amount of DOFs
- Return type
int
Example:
>>> prim.num_dof 9
- post_reset() None
[summary]
post reset articulation and qp_controller
- property prim: pxr.Usd.Prim
Returns: Usd.Prim: USD Prim object that this object holds.
- property prim_path: str
Returns: str: prim path in the stage
- set_angular_velocity(velocity: numpy.ndarray) None
Set the angular velocity of the root articulation prim
Warning
This method will immediately set the articulation state
- Parameters
velocity (np.ndarray) – 3D angular velocity vector. Shape (3,)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> prim.set_angular_velocity(np.array([0.1, 0.0, 0.0]))
- set_command_torque(_desired_joint_torque) None
Allow external nodes directly set robot command torque
_desired_joint_torque should be a 12x1 vector of torques
- set_default_state(position: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Set the default state of the prim (position and orientation), that will be used after each reset.
- Parameters
position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Example:
>>> # configure default state >>> prim.set_default_state(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1, 0, 0, 0])) >>> >>> # set default states during post-reset >>> prim.post_reset()
- set_enabled_self_collisions(flag: bool) None
Set the enable self collisions flag (
physxArticulation:enabledSelfCollisions)- Parameters
flag (bool) – whether to enable self collisions
Example:
>>> prim.set_enabled_self_collisions(True)
- set_joint_efforts(efforts: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint efforts
Note
This method can be used for effort control. For this purpose, there must be no joint drive or the stiffness and damping must be set to zero.
- Parameters
efforts (np.ndarray) – articulation joint efforts
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joint efforts to 0.0 >>> prim.set_joint_efforts(np.array([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0])) >>> >>> # set only the fingers efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 10 >>> prim.set_joint_efforts(np.array([10, 10]), joint_indices=np.array([7, 8]))
- set_joint_positions(positions: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint positions
Warning
This method will immediately set (teleport) the affected joints to the indicated value. Use the
apply_actionmethod to control robot joints.- Parameters
positions (np.ndarray) – articulation joint positions
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joints >>> prim.set_joint_positions(np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04])) >>> >>> # set only the fingers in closed position: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 0.0 >>> prim.set_joint_positions(np.array([0.04, 0.04]), joint_indices=np.array([7, 8]))
- set_joint_velocities(velocities: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint velocities
Warning
This method will immediately set the affected joints to the indicated value. Use the
apply_actionmethod to control robot joints.- Parameters
velocities (np.ndarray) – articulation joint velocities
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joint velocities to 0.0 >>> prim.set_joint_velocities(np.array([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0])) >>> >>> # set only the fingers velocities: panda_finger_joint1 (7) and panda_finger_joint2 (8) to -0.01 >>> prim.set_joint_velocities(np.array([-0.01, -0.01]), joint_indices=np.array([7, 8]))
- set_joints_default_state(positions: Optional[numpy.ndarray] = None, velocities: Optional[numpy.ndarray] = None, efforts: Optional[numpy.ndarray] = None) None
Set the joint default states (positions, velocities and/or efforts) to be applied after each reset.
Note
The default states will be set during post-reset (e.g., calling
.post_reset()orworld.reset()methods)- Parameters
positions (Optional[np.ndarray], optional) – joint positions. Defaults to None.
velocities (Optional[np.ndarray], optional) – joint velocities. Defaults to None.
efforts (Optional[np.ndarray], optional) – joint efforts. Defaults to None.
Example:
>>> # configure default joint states >>> prim.set_joints_default_state( ... positions=np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04]), ... velocities=np.zeros(shape=(prim.num_dof,)), ... efforts=np.zeros(shape=(prim.num_dof,)) ... ) >>> >>> # set default states during post-reset >>> prim.post_reset()
- set_linear_velocity(velocity: numpy.ndarray) None
Set the linear velocity of the root articulation prim
Warning
This method will immediately set the articulation state
- Parameters
velocity (np.ndarray) – 3D linear velocity vector. Shape (3,).
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> prim.set_linear_velocity(np.array([0.1, 0.0, 0.0]))
- set_local_pose(translation: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Set prim’s pose with respect to the local frame (the prim’s parent frame).
Warning
This method will change (teleport) the prim pose immediately to the indicated value
- Parameters
translation (Optional[Sequence[float]], optional) – translation in the local frame of the prim (with respect to its parent prim). shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the local frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Hint
This method belongs to the methods used to set the prim state
Example:
>>> prim.set_local_pose(translation=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))
- set_local_scale(scale: Optional[Sequence[float]]) None
Set prim’s scale with respect to the local frame (the prim’s parent frame).
- Parameters
scale (Optional[Sequence[float]]) – scale to be applied to the prim’s dimensions. shape is (3, ). Defaults to None, which means left unchanged.
Example:
>>> # scale prim 10 times smaller >>> prim.set_local_scale(np.array([0.1, 0.1, 0.1]))
- set_sleep_threshold(threshold: float) None
Set the threshold for articulations to enter a sleep state
Search for Articulations and Sleeping in PhysX docs for more details
- Parameters
threshold (float) – sleep threshold
Example:
>>> prim.set_sleep_threshold(0.01)
- set_solver_position_iteration_count(count: int) None
Set the solver (position) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
Warning
Setting a higher number of iterations may improve the fidelity of the simulation, although it may affect its performance.
- Parameters
count (int) – position iteration count
Example:
>>> prim.set_solver_position_iteration_count(64)
- set_solver_velocity_iteration_count(count: int)
Set the solver (velocity) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
Warning
Setting a higher number of iterations may improve the fidelity of the simulation, although it may affect its performance.
- Parameters
count (int) – velocity iteration count
Example:
>>> prim.set_solver_velocity_iteration_count(64)
- set_stabilization_threshold(threshold: float) None
Set the mass-normalized kinetic energy below which the articulation may participate in stabilization
Search for Stabilization Threshold in PhysX docs for more details
- Parameters
threshold (float) – stabilization threshold
Example:
>>> prim.set_stabilization_threshold(0.005)
- set_state(state: omni.isaac.quadruped.utils.a1_classes.A1State) None
[Summary]
Set the kinematic state of the robot.
- Parameters
set. (state {A1State} -- The state of the robot to) –
- Raises
RuntimeError – When the DC Toolbox interface has not been configured.
- set_visibility(visible: bool) None
Set the visibility of the prim in stage
- Parameters
visible (bool) – flag to set the visibility of the usd prim in stage.
Example:
>>> # make prim not visible in the stage >>> prim.set_visibility(visible=False)
- set_world_pose(position: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Ses prim’s pose with respect to the world’s frame
Warning
This method will change (teleport) the prim pose immediately to the indicated value
- Parameters
position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Hint
This method belongs to the methods used to set the prim state
Example:
>>> prim.set_world_pose(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))
- update()
[summary]
update robot sensor variables, state variables in A1Measurement
- update_contact_sensor_data() None
[summary]
Updates processed contact sensor data from the robot feets, store them in member variable foot_force
- update_imu_sensor_data()
[summary]
Updates processed imu sensor data from the robot body, store them in member variable base_lin and ang_vel
- class UnitreeVision(prim_path: str, name: str = 'unitree_quadruped', physics_dt: Optional[float] = 0.0025, usd_path: Optional[str] = None, position: Optional[numpy.ndarray] = None, orientation: Optional[numpy.ndarray] = None, model: Optional[str] = 'A1', is_ros2: Optional[bool] = False, way_points: Optional[numpy.ndarray] = None)
[Summary]
For unitree based quadrupeds (A1 or Go1) with camera
- advance(dt, goal, path_follow=False) numpy.ndarray
[summary]
calls the unitree advance to compute torque
Argument: dt {float} – Timestep update in the world. goal {List[int]} – x velocity, y velocity, angular velocity, state switch path_follow {bool} – True for following a set of coordinates, False for keyboard control
Returns: np.ndarray – The desired joint torques for the robot.
- apply_action(control_actions: omni.isaac.core.utils.types.ArticulationAction) None
Apply joint positions, velocities and/or efforts to control an articulation
- Parameters
control_actions (ArticulationAction) – actions to be applied for next physics step.
indices (Optional[Union[list, np.ndarray]], optional) – degree of freedom indices to apply actions to. Defaults to all degrees of freedom.
Hint
High stiffness makes the joints snap faster and harder to the desired target, and higher damping smoothes but also slows down the joint’s movement to target
For position control, set relatively high stiffness and low damping (to reduce vibrations)
For velocity control, stiffness must be set to zero with a non-zero damping
For effort control, stiffness and damping must be set to zero
Example:
>>> from omni.isaac.core.utils.types import ArticulationAction >>> >>> # move all the robot joints to the indicated position >>> action = ArticulationAction(joint_positions=np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04])) >>> prim.apply_action(action) >>> >>> # close the robot fingers: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 0.0 >>> action = ArticulationAction(joint_positions=np.array([0.0, 0.0]), joint_indices=np.array([7, 8])) >>> prim.apply_action(action)
- apply_visual_material(visual_material: omni.isaac.core.materials.visual_material.VisualMaterial, weaker_than_descendants: bool = False) None
Apply visual material to the held prim and optionally its descendants.
- Parameters
visual_material (VisualMaterial) – visual material to be applied to the held prim. Currently supports PreviewSurface, OmniPBR and OmniGlass.
weaker_than_descendants (bool, optional) – True if the material shouldn’t override the descendants materials, otherwise False. Defaults to False.
Example:
>>> from omni.isaac.core.materials import OmniGlass >>> >>> # create a dark-red glass visual material >>> material = OmniGlass( ... prim_path="/World/material/glass", # path to the material prim to create ... ior=1.25, ... depth=0.001, ... thin_walled=False, ... color=np.array([0.5, 0.0, 0.0]) ... ) >>> prim.apply_visual_material(material)
- property articulation_handle: int
A handler to the articulation
The handler is a unique identifier used by the Dynamic Control extension to manage the articulation
- Returns
handle
- Return type
int
Example:
>>> prim.articulation_handle 1116691496961
- disable_gravity() None
Keep gravity from affecting the robot
Example:
>>> prim.disable_gravity()
- dockViewports() None
[Summary]
For instantiating and docking view ports
- property dof_names: List[str]
List of prim names for each DOF.
- Returns
prim names
- Return type
list(string)
Example:
>>> prim.dof_names ['panda_joint1', 'panda_joint2', 'panda_joint3', 'panda_joint4', 'panda_joint5', 'panda_joint6', 'panda_joint7', 'panda_finger_joint1', 'panda_finger_joint2']
- property dof_properties: numpy.ndarray
Articulation DOF properties
DOF properties Index
Property name
Description
0
typeDOF type: invalid/unknown/uninitialized (0), rotation (1), translation (2)
1
hasLimitsWhether the DOF has limits
2
lowerLower DOF limit (in radians or meters)
3
upperUpper DOF limit (in radians or meters)
4
driveModeDrive mode for the DOF: force (1), acceleration (2)
5
maxVelocityMaximum DOF velocity. In radians/s, or stage_units/s
6
maxEffortMaximum DOF effort. In N or N*stage_units
7
stiffnessDOF stiffness
8
dampingDOF damping
- Returns
named NumPy array of shape (num_dof, 9)
- Return type
np.ndarray
Example:
>>> # get properties for all DOFs >>> prim.dof_properties [(1, True, -2.8973, 2.8973, 1, 1.0000000e+01, 5220., 60000., 3000.) (1, True, -1.7628, 1.7628, 1, 1.0000000e+01, 5220., 60000., 3000.) (1, True, -2.8973, 2.8973, 1, 5.9390470e+36, 5220., 60000., 3000.) (1, True, -3.0718, -0.0698, 1, 5.9390470e+36, 5220., 60000., 3000.) (1, True, -2.8973, 2.8973, 1, 5.9390470e+36, 720., 25000., 3000.) (1, True, -0.0175, 3.7525, 1, 5.9390470e+36, 720., 15000., 3000.) (1, True, -2.8973, 2.8973, 1, 1.0000000e+01, 720., 5000., 3000.) (2, True, 0. , 0.04 , 1, 3.4028235e+38, 720., 6000., 1000.) (2, True, 0. , 0.04 , 1, 3.4028235e+38, 720., 6000., 1000.)] >>> >>> # property names >>> prim.dof_properties.dtype.names ('type', 'hasLimits', 'lower', 'upper', 'driveMode', 'maxVelocity', 'maxEffort', 'stiffness', 'damping') >>> >>> # get DOF upper limits >>> prim.dof_properties["upper"] [ 2.8973 1.7628 2.8973 -0.0698 2.8973 3.7525 2.8973 0.04 0.04 ] >>> >>> # get the last DOF (panda_finger_joint2) upper limit >>> prim.dof_properties["upper"][8] # or prim.dof_properties[8][3] 0.04
- enable_gravity() None
Gravity will affect the robot
Example:
>>> prim.enable_gravity()
- get_angular_velocity() numpy.ndarray
Get the angular velocity of the root articulation prim
- Returns
3D angular velocity vector. Shape (3,)
- Return type
np.ndarray
Example:
>>> prim.get_angular_velocity() [0. 0. 0.]
- get_applied_action() omni.isaac.core.utils.types.ArticulationAction
Get the last applied action
- Returns
last applied action. Note: a dictionary is used as the object’s string representation
- Return type
Example:
>>> # last applied action: joint_positions -> [0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04] >>> prim.get_applied_action() {'joint_positions': [0.0, -1.0, 0.0, -2.200000047683716, 0.0, 2.4000000953674316, 0.800000011920929, 0.03999999910593033, 0.03999999910593033], 'joint_velocities': [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0], 'joint_efforts': [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]}
- get_applied_joint_efforts(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the efforts applied to the joints set by the
set_joint_effortsmethod- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
all or selected articulation joint applied efforts
- Return type
np.ndarray
Example:
>>> # get all applied joint efforts >>> prim.get_applied_joint_efforts() [ 0. 0. 0. 0. 0. 0. 0. 0. 0.] >>> >>> # get finger applied efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_applied_joint_efforts(joint_indices=np.array([7, 8])) [0. 0.]
- get_applied_visual_material() omni.isaac.core.materials.visual_material.VisualMaterial
Return the current applied visual material in case it was applied using apply_visual_material or it’s one of the following materials that was already applied before: PreviewSurface, OmniPBR and OmniGlass.
- Returns
the current applied visual material if its type is currently supported.
- Return type
Example:
>>> # given a visual material applied >>> prim.get_applied_visual_material() <omni.isaac.core.materials.omni_glass.OmniGlass object at 0x7f36263106a0>
- get_articulation_body_count() int
Get the number of bodies (links) that make up the articulation
- Returns
amount of bodies
- Return type
int
Example:
>>> prim.get_articulation_body_count() 12
- get_articulation_controller() omni.isaac.core.controllers.articulation_controller.ArticulationController
Get the articulation controller
Note
If no
articulation_controllerwas passed during class instantiation, a default controller of typeArticulationController(a Proportional-Derivative controller that can apply position targets, velocity targets and efforts) will be used- Returns
articulation controller
- Return type
Example:
>>> prim.get_articulation_controller() <omni.isaac.core.controllers.articulation_controller.ArticulationController object at 0x7f04a0060190>
- get_default_state() omni.isaac.core.utils.types.XFormPrimState
Get the default prim states (spatial position and orientation).
- Returns
an object that contains the default state of the prim (position and orientation)
- Return type
Example:
>>> state = prim.get_default_state() >>> state <omni.isaac.core.utils.types.XFormPrimState object at 0x7f33addda650> >>> >>> state.position [-4.5299529e-08 -1.8347054e-09 -2.8610229e-08] >>> state.orientation [1. 0. 0. 0.]
- get_dof_index(dof_name: str) int
Get a DOF index given its name
- Parameters
dof_name (str) – name of the DOF
- Returns
DOF index
- Return type
int
Example:
>>> prim.get_dof_index("panda_finger_joint2") 8
- get_enabled_self_collisions() int
Get the enable self collisions flag (
physxArticulation:enabledSelfCollisions)- Returns
self collisions flag (boolean interpreted as int)
- Return type
int
Example:
>>> prim.get_enabled_self_collisions() 0
- get_joint_positions(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the articulation joint positions
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Returns
all or selected articulation joint positions
- Return type
np.ndarray
Example:
>>> # get all joint positions >>> prim.get_joint_positions() [ 1.1999920e-02 -5.6962633e-01 1.3480479e-08 -2.8105433e+00 6.8284894e-06 3.0301569e+00 7.3234749e-01 3.9912373e-02 3.9999999e-02] >>> >>> # get finger positions: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_joint_positions(joint_indices=np.array([7, 8])) [0.03991237 3.9999999e-02]
- get_joint_velocities(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the articulation joint velocities
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Returns
all or selected articulation joint velocities
- Return type
np.ndarray
Example:
>>> # get all joint velocities >>> prim.get_joint_velocities() [ 1.91603772e-06 -7.67638255e-03 -2.19138826e-07 1.10636465e-02 -4.63412944e-05 3.48245539e-02 8.84692147e-02 5.40335372e-04 1.02849208e-05] >>> >>> # get finger velocities: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_joint_velocities(joint_indices=np.array([7, 8])) [5.4033537e-04 1.0284921e-05]
- get_joints_default_state() omni.isaac.core.utils.types.JointsState
Get the default joint states (positions and velocities).
- Returns
an object that contains the default joint positions and velocities
- Return type
Example:
>>> state = prim.get_joints_default_state() >>> state <omni.isaac.core.utils.types.JointsState object at 0x7f04a0061240> >>> >>> state.positions [ 0.012 -0.57000005 0. -2.81 0. 3.037 0.785398 0.04 0.04 ] >>> state.velocities [0. 0. 0. 0. 0. 0. 0. 0. 0.]
- get_joints_state() omni.isaac.core.utils.types.JointsState
Get the current joint states (positions and velocities)
- Returns
an object that contains the current joint positions and velocities
- Return type
Example:
>>> state = prim.get_joints_state() >>> state <omni.isaac.core.utils.types.JointsState object at 0x7f02f6df57b0> >>> >>> state.positions [ 1.1999920e-02 -5.6962633e-01 1.3480479e-08 -2.8105433e+00 6.8284894e-06 3.0301569e+00 7.3234749e-01 3.9912373e-02 3.9999999e-02] >>> state.velocities [ 1.91603772e-06 -7.67638255e-03 -2.19138826e-07 1.10636465e-02 -4.63412944e-05 245539e-02 8.84692147e-02 5.40335372e-04 1.02849208e-05]
- get_linear_velocity() numpy.ndarray
Get the linear velocity of the root articulation prim
- Returns
3D linear velocity vector. Shape (3,)
- Return type
np.ndarray
Example:
>>> prim.get_linear_velocity() [0. 0. 0.]
- get_local_pose() Tuple[numpy.ndarray, numpy.ndarray]
Get prim’s pose with respect to the local frame (the prim’s parent frame)
- Returns
first index is the position in the local frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the local frame
- Return type
Tuple[np.ndarray, np.ndarray]
Example:
>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame >>> position, orientation = prim.get_local_pose() >>> position [0. 0. 0.] >>> orientation [0. 0. 0.]
- get_local_scale() numpy.ndarray
Get prim’s scale with respect to the local frame (the parent’s frame)
- Returns
scale applied to the prim’s dimensions in the local frame. shape is (3, ).
- Return type
np.ndarray
Example:
>>> prim.get_local_scale() [1. 1. 1.]
- get_measured_joint_efforts(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Returns the efforts computed/measured by the physics solver of the joint forces in the DOF motion direction
- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
all or selected articulation joint measured efforts
- Return type
np.ndarray
Example:
>>> # get all joint efforts >>> prim.get_measured_joint_efforts() [ 2.7897308e-06 -6.9083519e+00 -3.6398471e-06 1.9158335e+01 -4.3552645e-06 1.1866090e+00 -4.7079347e-06 3.2339853e-04 -3.2044132e-04] >>> >>> # get finger efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) >>> prim.get_measured_joint_efforts(joint_indices=np.array([7, 8])) [ 0.0003234 -0.00032044]
- get_measured_joint_forces(joint_indices: Optional[Union[List, numpy.ndarray]] = None) numpy.ndarray
Get the measured joint reaction forces and torques (link incoming joint forces and torques) to external loads
Note
Since the name->index map for joints has not been exposed yet, it is possible to access the joint names and their indices through the articulation metadata.
prim._articulation_view._metadata.joint_names # list of names prim._articulation_view._metadata.joint_indices # dict of name: index
To retrieve a specific row for the link incoming joint force/torque use
joint_index + 1- Parameters
joint_indices (Optional[Union[List, np.ndarray]], optional) – indices to specify which joints to read. Defaults to None (all joints)
- Raises
Exception – If the handlers are not initialized
- Returns
measured joint forces and torques. Shape is (num_joint + 1, 6). Row index 0 is the incoming joint of the base link. For the last dimension the first 3 values are for forces and the last 3 for torques
- Return type
np.ndarray
Example:
>>> # get all measured joint forces and torques >>> prim.get_measured_joint_forces() [[ 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00 0.0000000e+00] [ 1.4995076e+02 4.2574748e-06 5.6364370e-04 4.8701895e-05 -6.9072924e+00 3.1881387e-05] [-2.8971717e-05 -1.0677823e+02 -6.8384506e+01 -6.9072924e+00 -5.4927128e-05 6.1222494e-07] [ 8.7120995e+01 -4.3871860e-05 -5.5795174e+01 5.3687054e-05 -2.4538563e+01 1.3333466e-05] [ 5.3519474e-05 -4.8109909e+01 6.0709282e+01 1.9157074e+01 -5.9258469e-05 8.2744418e-07] [-3.1691040e+01 2.3313689e-04 3.9990173e+01 -5.8968733e-05 -1.1863431e+00 2.2335558e-05] [-1.0809851e-04 1.5340537e+01 -1.5458489e+01 1.1863426e+00 6.1094368e-05 -1.5940281e-05] [-7.5418940e+00 -5.0814648e+00 -5.6512990e+00 -5.6385466e-05 3.8859999e-01 -3.4943256e-01] [ 4.7421460e+00 -3.1945827e+00 3.5528181e+00 5.5852943e-05 8.4794536e-03 7.6405057e-03] [ 4.0760727e+00 2.1640673e-01 -4.0513167e+00 -5.9565349e-04 1.1407082e-02 2.1432268e-06] [ 5.1680198e-03 -9.7754575e-02 -9.7093947e-02 -8.4155556e-12 -1.2910691e-12 -1.9347857e-11] [-5.1910793e-03 9.7588278e-02 -9.7106412e-02 8.4155573e-12 1.2910637e-12 -1.9347855e-11]] >>> >>> # get measured joint force and torque for the fingers >>> metadata = prim._articulation_view._metadata >>> joint_indices = 1 + np.array([ ... metadata.joint_indices["panda_finger_joint1"], ... metadata.joint_indices["panda_finger_joint2"], ... ]) >>> joint_indices [10 11] >>> prim.get_measured_joint_forces(joint_indices) [[ 5.1680198e-03 -9.7754575e-02 -9.7093947e-02 -8.4155556e-12 -1.2910691e-12 -1.9347857e-11] [-5.1910793e-03 9.7588278e-02 -9.7106412e-02 8.4155573e-12 1.2910637e-12 -1.9347855e-11]]
- get_sleep_threshold() float
Get the threshold for articulations to enter a sleep state
Search for Articulations and Sleeping in PhysX docs for more details
- Returns
sleep threshold
- Return type
float
Example:
>>> prim.get_sleep_threshold() 0.005
- get_solver_position_iteration_count() int
Get the solver (position) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
- Returns
position iteration count
- Return type
int
Example:
>>> prim.get_solver_position_iteration_count() 32
- get_solver_velocity_iteration_count() int
Get the solver (velocity) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
- Returns
velocity iteration count
- Return type
int
Example:
>>> prim.get_solver_velocity_iteration_count() 32
- get_stabilization_threshold() float
Get the mass-normalized kinetic energy below which the articulation may participate in stabilization
Search for Stabilization Threshold in PhysX docs for more details
- Returns
stabilization threshold
- Return type
float
Example:
>>> prim.get_stabilization_threshold() 0.0009999999
- get_visibility() bool
- Returns
true if the prim is visible in stage. false otherwise.
- Return type
bool
Example:
>>> # get the visible state of an visible prim on the stage >>> prim.get_visibility() True
- get_world_pose() Tuple[numpy.ndarray, numpy.ndarray]
Get prim’s pose with respect to the world’s frame
- Returns
first index is the position in the world frame (with shape (3, )). Second index is quaternion orientation (with shape (4, )) in the world frame
- Return type
Tuple[np.ndarray, np.ndarray]
Example:
>>> # if the prim is in position (1.0, 0.5, 0.0) with respect to the world frame >>> position, orientation = prim.get_world_pose() >>> position [1. 0.5 0. ] >>> orientation [1. 0. 0. 0.]
- get_world_scale() numpy.ndarray
Get prim’s scale with respect to the world’s frame
- Returns
scale applied to the prim’s dimensions in the world frame. shape is (3, ).
- Return type
np.ndarray
Example:
>>> prim.get_world_scale() [1. 1. 1.]
- property handles_initialized: bool
Check if articulation handler is initialized
- Returns
whether the handler was initialized
- Return type
bool
Example:
>>> prim.handles_initialized True
- initialize(physics_sim_view=None) None
[summary]
initialize dc interface, set up drive mode and initial robot state
- is_valid() bool
Check if the prim path has a valid USD Prim at it
- Returns
True is the current prim path corresponds to a valid prim in stage. False otherwise.
- Return type
bool
Example:
>>> # given an existing and valid prim >>> prims.is_valid() True
- is_visual_material_applied() bool
Check if there is a visual material applied
- Returns
True if there is a visual material applied. False otherwise.
- Return type
bool
Example:
>>> # given a visual material applied >>> prim.is_visual_material_applied() True
- property name: Optional[str]
Returns: str: name given to the prim when instantiating it. Otherwise None.
- property non_root_articulation_link: bool
Used to query if the prim is a non root articulation link
- Returns
True if the prim itself is a non root link
- Return type
bool
Example:
>>> # for a wrapped articulation (where the root prim has the Physics Articulation Root property applied) >>> prim.non_root_articulation_link False
- property num_dof: int
Number of DOF of the articulation
- Returns
amount of DOFs
- Return type
int
Example:
>>> prim.num_dof 9
- post_reset() None
[summary]
post reset articulation and qp_controller
- property prim: pxr.Usd.Prim
Returns: Usd.Prim: USD Prim object that this object holds.
- property prim_path: str
Returns: str: prim path in the stage
- setCameraExeutionStep(step: numpy.uint64) None
[Summary]
Sets the execution step in the omni.isaac.core_nodes.IsaacSimulationGate node located in the camera sensor pipeline
- set_angular_velocity(velocity: numpy.ndarray) None
Set the angular velocity of the root articulation prim
Warning
This method will immediately set the articulation state
- Parameters
velocity (np.ndarray) – 3D angular velocity vector. Shape (3,)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> prim.set_angular_velocity(np.array([0.1, 0.0, 0.0]))
- set_default_state(position: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Set the default state of the prim (position and orientation), that will be used after each reset.
- Parameters
position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Example:
>>> # configure default state >>> prim.set_default_state(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1, 0, 0, 0])) >>> >>> # set default states during post-reset >>> prim.post_reset()
- set_enabled_self_collisions(flag: bool) None
Set the enable self collisions flag (
physxArticulation:enabledSelfCollisions)- Parameters
flag (bool) – whether to enable self collisions
Example:
>>> prim.set_enabled_self_collisions(True)
- set_joint_efforts(efforts: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint efforts
Note
This method can be used for effort control. For this purpose, there must be no joint drive or the stiffness and damping must be set to zero.
- Parameters
efforts (np.ndarray) – articulation joint efforts
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joint efforts to 0.0 >>> prim.set_joint_efforts(np.array([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0])) >>> >>> # set only the fingers efforts: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 10 >>> prim.set_joint_efforts(np.array([10, 10]), joint_indices=np.array([7, 8]))
- set_joint_positions(positions: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint positions
Warning
This method will immediately set (teleport) the affected joints to the indicated value. Use the
apply_actionmethod to control robot joints.- Parameters
positions (np.ndarray) – articulation joint positions
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joints >>> prim.set_joint_positions(np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04])) >>> >>> # set only the fingers in closed position: panda_finger_joint1 (7) and panda_finger_joint2 (8) to 0.0 >>> prim.set_joint_positions(np.array([0.04, 0.04]), joint_indices=np.array([7, 8]))
- set_joint_velocities(velocities: numpy.ndarray, joint_indices: Optional[Union[List, numpy.ndarray]] = None) None
Set the articulation joint velocities
Warning
This method will immediately set the affected joints to the indicated value. Use the
apply_actionmethod to control robot joints.- Parameters
velocities (np.ndarray) – articulation joint velocities
joint_indices (Optional[Union[list, np.ndarray]], optional) – indices to specify which joints to manipulate. Defaults to None (all joints)
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> # set all the robot joint velocities to 0.0 >>> prim.set_joint_velocities(np.array([0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0])) >>> >>> # set only the fingers velocities: panda_finger_joint1 (7) and panda_finger_joint2 (8) to -0.01 >>> prim.set_joint_velocities(np.array([-0.01, -0.01]), joint_indices=np.array([7, 8]))
- set_joints_default_state(positions: Optional[numpy.ndarray] = None, velocities: Optional[numpy.ndarray] = None, efforts: Optional[numpy.ndarray] = None) None
Set the joint default states (positions, velocities and/or efforts) to be applied after each reset.
Note
The default states will be set during post-reset (e.g., calling
.post_reset()orworld.reset()methods)- Parameters
positions (Optional[np.ndarray], optional) – joint positions. Defaults to None.
velocities (Optional[np.ndarray], optional) – joint velocities. Defaults to None.
efforts (Optional[np.ndarray], optional) – joint efforts. Defaults to None.
Example:
>>> # configure default joint states >>> prim.set_joints_default_state( ... positions=np.array([0.0, -1.0, 0.0, -2.2, 0.0, 2.4, 0.8, 0.04, 0.04]), ... velocities=np.zeros(shape=(prim.num_dof,)), ... efforts=np.zeros(shape=(prim.num_dof,)) ... ) >>> >>> # set default states during post-reset >>> prim.post_reset()
- set_linear_velocity(velocity: numpy.ndarray) None
Set the linear velocity of the root articulation prim
Warning
This method will immediately set the articulation state
- Parameters
velocity (np.ndarray) – 3D linear velocity vector. Shape (3,).
Hint
This method belongs to the methods used to set the articulation kinematic state:
set_linear_velocity,set_angular_velocity,set_joint_positions,set_joint_velocities,set_joint_effortsExample:
>>> prim.set_linear_velocity(np.array([0.1, 0.0, 0.0]))
- set_local_pose(translation: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Set prim’s pose with respect to the local frame (the prim’s parent frame).
Warning
This method will change (teleport) the prim pose immediately to the indicated value
- Parameters
translation (Optional[Sequence[float]], optional) – translation in the local frame of the prim (with respect to its parent prim). shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the local frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Hint
This method belongs to the methods used to set the prim state
Example:
>>> prim.set_local_pose(translation=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))
- set_local_scale(scale: Optional[Sequence[float]]) None
Set prim’s scale with respect to the local frame (the prim’s parent frame).
- Parameters
scale (Optional[Sequence[float]]) – scale to be applied to the prim’s dimensions. shape is (3, ). Defaults to None, which means left unchanged.
Example:
>>> # scale prim 10 times smaller >>> prim.set_local_scale(np.array([0.1, 0.1, 0.1]))
- set_sleep_threshold(threshold: float) None
Set the threshold for articulations to enter a sleep state
Search for Articulations and Sleeping in PhysX docs for more details
- Parameters
threshold (float) – sleep threshold
Example:
>>> prim.set_sleep_threshold(0.01)
- set_solver_position_iteration_count(count: int) None
Set the solver (position) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
Warning
Setting a higher number of iterations may improve the fidelity of the simulation, although it may affect its performance.
- Parameters
count (int) – position iteration count
Example:
>>> prim.set_solver_position_iteration_count(64)
- set_solver_velocity_iteration_count(count: int)
Set the solver (velocity) iteration count for the articulation
The solver iteration count determines how accurately contacts, drives, and limits are resolved. Search for Solver Iteration Count in PhysX docs for more details.
Warning
Setting a higher number of iterations may improve the fidelity of the simulation, although it may affect its performance.
- Parameters
count (int) – velocity iteration count
Example:
>>> prim.set_solver_velocity_iteration_count(64)
- set_stabilization_threshold(threshold: float) None
Set the mass-normalized kinetic energy below which the articulation may participate in stabilization
Search for Stabilization Threshold in PhysX docs for more details
- Parameters
threshold (float) – stabilization threshold
Example:
>>> prim.set_stabilization_threshold(0.005)
- set_state(state: omni.isaac.quadruped.utils.a1_classes.A1State) None
[Summary]
Set the kinematic state of the robot.
- Parameters
set. (state {A1State} -- The state of the robot to) –
- Raises
RuntimeError – When the DC Toolbox interface has not been configured.
- set_visibility(visible: bool) None
Set the visibility of the prim in stage
- Parameters
visible (bool) – flag to set the visibility of the usd prim in stage.
Example:
>>> # make prim not visible in the stage >>> prim.set_visibility(visible=False)
- set_world_pose(position: Optional[Sequence[float]] = None, orientation: Optional[Sequence[float]] = None) None
Ses prim’s pose with respect to the world’s frame
Warning
This method will change (teleport) the prim pose immediately to the indicated value
- Parameters
position (Optional[Sequence[float]], optional) – position in the world frame of the prim. shape is (3, ). Defaults to None, which means left unchanged.
orientation (Optional[Sequence[float]], optional) – quaternion orientation in the world frame of the prim. quaternion is scalar-first (w, x, y, z). shape is (4, ). Defaults to None, which means left unchanged.
Hint
This method belongs to the methods used to set the prim state
Example:
>>> prim.set_world_pose(position=np.array([1.0, 0.5, 0.0]), orientation=np.array([1., 0., 0., 0.]))
- update() None
[Summary]
Update robot variables from the environment
- update_contact_sensor_data() None
[summary]
Updates processed contact sensor data from the robot feets, store them in member variable foot_force
- update_imu_sensor_data() None
[summary]
Updates processed imu sensor data from the robot body, store them in member variable base_lin and ang_vel