ArticulatedModel

class mplib.ArticulatedModel

Bases: pybind11_object

Supports initialization from URDF and SRDF files, and provides access to underlying Pinocchio and FCL models.

__init__(
self: mplib.pymp.ArticulatedModel,
urdf_filename: str,
srdf_filename: str,
*,
name: str = None,
gravity: numpy.ndarray[numpy.float64[3, 1]] = array([0., 0., -9.81]),
link_names: list[str] = [],
joint_names: list[str] = [],
convex: bool = False,
verbose: bool = False,
) → None

Construct an articulated model from URDF and SRDF files.

Parameters:

  • urdf_filename – path to URDF file, can be relative to the current working directory

  • srdf_filename – path to SRDF file, we use it to disable self-collisions

  • name – name of the articulated model to override URDF robot name attribute

  • gravity – gravity vector, by default is [0, 0, -9.81] in -z axis

  • link_names – list of links that are considered for planning

  • joint_names – list of joints that are considered for planning

  • convex – use convex decomposition for collision objects. Default: False.

  • verbose – print debug information. Default: False.

property base_pose

The base (root) pose of the robot

static create_from_urdf_string(
urdf_string: str,
srdf_string: str,
collision_links: list[mplib.pymp.collision_detection.fcl.FCLObject],
*,
name: str = None,
gravity: numpy.ndarray[numpy.float64[3, 1]] = array([0., 0., -9.81]),
link_names: list[str] = [],
joint_names: list[str] = [],
verbose: bool = False,
) → mplib.pymp.ArticulatedModel

Constructs an ArticulatedModel from URDF/SRDF strings and collision links

Parameters:

  • urdf_string – URDF string (without visual/collision elements for links)

  • srdf_string – SRDF string (only disable_collisions element)

  • collision_links – Vector of collision links as FCLObjectPtr. Format is: [FCLObjectPtr, ...]. The collision objects are at the shape’s local_pose.

  • name – name of the articulated model to override URDF robot name attribute

  • gravity – gravity vector, by default is [0, 0, -9.81] in -z axis

  • link_names – list of links that are considered for planning

  • joint_names – list of joints that are considered for planning

  • verbose – print debug information. Default: False.

Returns:

a unique_ptr to ArticulatedModel

get_base_pose(self: mplib.pymp.ArticulatedModel) → mplib.pymp.Pose

Get the base (root) pose of the robot.

Returns:

base pose of the robot

get_fcl_model(
self: mplib.pymp.ArticulatedModel,
) → mplib.pymp.collision_detection.fcl.FCLModel

Get the underlying FCL model.

Returns:

FCL model used for collision checking

get_move_group_end_effectors(
self: mplib.pymp.ArticulatedModel,
) → list[str]

Get the end effectors of the move group.

Returns:

list of end effectors of the move group

get_move_group_joint_indices(
self: mplib.pymp.ArticulatedModel,
) → list[int]

Get the joint indices of the move group.

Returns:

list of user joint indices of the move group

get_move_group_joint_names(
self: mplib.pymp.ArticulatedModel,
) → list[str]

Get the joint names of the move group.

Returns:

list of joint names of the move group

get_move_group_qpos_dim(self: mplib.pymp.ArticulatedModel) → int

Get the dimension of the move group qpos.

Returns:

dimension of the move group qpos

get_name(self: mplib.pymp.ArticulatedModel) → str

Get name of the articulated model.

Returns:

name of the articulated model

get_pinocchio_model(
self: mplib.pymp.ArticulatedModel,
) → mplib.pymp.kinematics.pinocchio.PinocchioModel

Get the underlying Pinocchio model.

Returns:

Pinocchio model used for kinematics and dynamics computations

get_pose(self: mplib.pymp.ArticulatedModel) → mplib.pymp.Pose

Get the base (root) pose of the robot.

Returns:

base pose of the robot

get_qpos(
self: mplib.pymp.ArticulatedModel,
) → numpy.ndarray[numpy.float64[m, 1]]

Get the current joint position of all active joints inside the URDF.

Returns:

current qpos of all active joints

get_user_joint_names(self: mplib.pymp.ArticulatedModel) → list[str]

Get the joint names that the user has provided for planning.

Returns:

list of joint names of the user

Get the link names that the user has provided for planning.

Returns:

list of link names of the user

property name

Name of the articulated model

property pose

The base (root) pose of the robot

property qpos

Current qpos of all active joints

set_base_pose(
self: mplib.pymp.ArticulatedModel,
pose: mplib.pymp.Pose,
) → None

Set the base pose of the robot and update all collision links in the FCLModel.

Parameters:

pose – base pose of the robot

set_move_group(*args, **kwargs)

Overloaded function.

  1. set_move_group(self: mplib.pymp.ArticulatedModel, end_effector: str) -> None

Set the move group, i.e. the chain ending in end effector for which to compute the forward kinematics for all subsequent queries.

Parameters:

end_effector – name of the end effector link

  1. set_move_group(self: mplib.pymp.ArticulatedModel, end_effectors: list[str]) -> None

Set the move group but we have multiple end effectors in a chain. I.e., Base –> EE1 –> EE2 –> … –> EEn

Parameters:

end_effectors – list of links extending to the end effector

set_pose(
self: mplib.pymp.ArticulatedModel,
pose: mplib.pymp.Pose,
) → None

Set the base pose of the robot and update all collision links in the FCLModel.

Parameters:

pose – base pose of the robot

set_qpos(
self: mplib.pymp.ArticulatedModel,
qpos: numpy.ndarray[numpy.float64[m, 1]],
full: bool = False,
) → None

Set the current joint positions and update all collision links in the FCLModel.

Parameters:

  • qpos – current qpos of all active joints or just the move group joints

  • full – whether to set the full qpos or just the move group qpos. If full is False, we will pad the missing joints with current known qpos. The default is False

update_SRDF(self: mplib.pymp.ArticulatedModel, SRDF: str) → None

Update the SRDF file to disable self-collisions.

Parameters:

srdf – path to SRDF file, can be relative to the current working directory