Robot Interfaces¶

Interface for obtaining robot state and sending robot control commands. RobotInterfaces are specific to the world they inhabit, as well as the type of robot. They contain Controllers for converting desired goal states to a set of joint torques.

RobotInterface¶

class perls2.robots.robot_interface.RobotInterface(config, controlType=None)¶

Abstract interface to be implemented for each real and simulated robot.

action_set¶

flag describing if action for controller has been set.

Type: bool

config¶

Dictionary describing robot parameters.

Type: dict

control_type¶

Type of controller for robot to use e.g. “EEImpedance”, “JointVelocity”

Type: str

interpolator_pos¶

Interpolator for ee/joint position

Type: perls2.interpolator.linear_interpolator

interpolator_ori¶

Interpolator for ee orientation

Type: perls2.interpolator.linear_interpolator

model¶

a model of the robot state as defined by tq_control.

Type: Model

controller¶

tq_control object that takes robot states and compute torques.

Type: Controller

step()¶: Update the robot state and model, set torques from controller.

change_controller(next_type)¶

Change to a different controller type.

Parameters: next_type (str) – keyword for desired control type. Choose from: -‘EEImpedance’ -‘EEPosture’ -‘JointVelocity’ -‘JointImpedance’ -‘JointTorque’

update()¶: Update robot interface model with states for controller.

update_model()¶: Update robot model with states and dynamics.

make_controller(control_type)¶

Returns a new controller type based on specs.

Parameters: control_type (str) – name of the control type.

set_controller_goal(**kwargs)¶

Update model and set the goal for controller.

Parameters: kwargs (dict) – arguments specific to controller for setting goal.

move_ee_delta(delta, set_pos=None, set_ori=None)¶

Use controller to move end effector by some delta.

Parameters

delta (6f) – delta position (dx, dy, dz) concatenated with delta orientation. Orientation change is specified as an axis angle rotation from previous orientation.
set_pos (3f) – end effector position to maintain while changing orientation. [x, y, z]. If not None, the delta for position is ignored.
set_ori (4f) – end effector orientation to maintain while changing orientation as a quaternion [qx, qy, qz, w]. If not None, any delta for orientation is ignored.

Notes

To fix position or orientation, it is better to specify using the kwargs than to use a 0 for the corresponding delta. This prevents any error from accumulating in that dimension.

Examples

Specify delta holding fixed orientation:: self.robot_interface.move_ee_delta([0.1, 0, 0, 0, 0, 0], set_pos=None, set_ori=[0, 0, 0, 1])

set_ee_pose(set_pos, set_ori, **kwargs)¶

Use controller to set end effector pose.

Parameters

set_pos (list) – 3f [x, y , z] desired absolute ee position in world frame.
set_ori (list) – 4f [qx, qy, qz, w] desired absolute ee orientation in world frame.
**kwargs (dict) – used to catch all other arguments.

Returns

None

Notes: Only for use with EEImpedance and EEPosture controller.

set_joint_positions(set_qpos, **kwargs)¶

Use controller to set new joint positions.

Parameters: set_qpos – 7f absolute joint positions (rad)
Returns: None

Notes: Only for use with Joint Impedance Controller

set_joint_delta(delta, **kwargs)¶

Use controller to set new joint position with a delta.

Parameters: delta (ndarray) – 7f delta joint position (rad) from current joint position.

Returns: None

Notes: Only for use with JointImpedance controller.: Does not check for exceeding maximum joint limits. (TODO)

set_joint_velocities(velocities)¶

Use controller to set joint velocity of the robot.

Parameters

velocities (list) – 7f desired joint velocities (rad/s) for each joint.
0 is the base (Joint) –

Returns: None.

Notes: Only for use with JointVelocity controller.

set_joint_torques(torques)¶

Set joint torques to new joint torques.

Parameters: torques (list) – 7f list of toruqes to command.

Notes

Only for use with Joint Torque Controlle

abstract open_gripper()¶: Open robot gripper.

abstract close_gripper()¶: Close robot gripper

abstract set_gripper_to_value(value)¶: Set gripper to desired open/close value

abstract property name¶: str of the name of the robot

abstract property ee_pose¶: list of seven floats [x, y, z, qx, qy, qz, qw] of the 6D pose of the end effector.

abstract property ee_position¶: list of three floats [x, y, z] of the position of the end-effector.

abstract property ee_orientation¶: list of four floats [qx, qy, qz, qw] of the orientation quaternion of the end-effector.

abstract property ee_v¶: list of seven floats [x, y, z, qx, qy, qz, qw] of the 6D pose of the end effector.

abstract property ee_w¶: list of seven floats [x, y, z, qx, qy, qz, qw] of the 6D pose of the end effector.

abstract property ee_twist¶: list of seven floats [x, y, z, qx, qy, qz, qw] of the 6D pose of the end effector.

abstract property q¶

List of 7f describing joint positions (rad) of the robot arm.