screwmpcpy 0.2.2

Dual Quaternion based MPC generating screw motion for n-DOF robot arm.

screwmpcpy

Generate smooth motions for a n-DOF robot arm end effector using Dual Quaternions while enforcing velocity-, acceleration- and jerk constraints. The package includes a base optimization scheme and a base motion generator, which can be easily extended for custom robot arms. A motion generator for the Franka Emika Panda robot is included.

Install

Getting started

Extending the available robots

For adding your custom robot arm, you easily can extend the base class. Make sure the forward kinematics of your robot are available.
Create a new file your_robot_mg.py in folder src/screwmpc.py.

Custom robot example

from dqrobotics import DQ
from .basemg import BaseMotionGenerator
from .screwmpc import BOUND


class YourRobotMotionGenerator(BaseMotionGenerator):

    def __init__(
                self,
                n_p: int,
                n_c: int,
                q_mpc: float,
                r_mpc: float,
                lu_bound_vel: BOUND,
                lu_bound_acc: BOUND,
                lu_bound_jerk: BOUND,
                ) -> None:
        super().__init__(
            n_p, n_c, q_mpc, r_mpc, lu_bound_vel, lu_bound_acc, lu_bound_jerk
        )
        # custom attributes here
        self._kin = YourRobotKinematics()

    def step(self, q_robot: np.ndarray, goal: DQ) -> np.ndarray:

        # Initialize Dual Quaternion with 6D pose
        x_current = DQ(self._kin.your_forward_kinematics(q_robot))
        error, smooth_traj = super()._step(x_current, goal)
        # calculate commanded dq here
        ...
        return dq