Get Target Joint Accelerations

SUMMARY

Get Target Joint Accelerations returns the joint-acceleration setpoint the controller is currently commanding (deg/s², base to wrist) - the desired acceleration reference generated by the trajectory planner.

Reads from the manipulator state - live controller setpoint when connected, zero-filled offline.

UNITS

Returns target joint accelerations in deg/s², ordered base to wrist.

The Skill

qdd = robot.get_target_joint_accelerations()

The Code

"""
Logs the controller-commanded target joint accelerations.

Supports Universal Robots (UR), Epson, virtual, and Isaac Sim.

Usage:
    python get_target_joint_accelerations.py [--ip <ROBOT_IP>] [--prim_path <PRIM_PATH>]
"""

import argparse

from loguru import logger

from telekinesis.synapse.robots.manipulators import universal_robots


def main(ip: str | None, prim_path: str | None) -> None:
    """Log the controller-commanded target joint accelerations [deg/s²]."""

    #===================== Create Robot ==========================================
    robot = universal_robots.UniversalRobotsUR10E(name='UR10e')

    try:
        #===================== Connect Robot ==========================================
        if ip:
            robot.connect(ip=ip)
        elif prim_path:
            robot.connect(simulation_prim_path=prim_path)
            robot.set_joint_positions(robot.default_joint_configuration)

        # ==================== Run Skill ============================================
        logger.success(f"target_joint_accelerations [deg/s^2]: {robot.get_target_joint_accelerations()}")
    except (ConnectionError, OSError) as e:
        logger.error(f"Error occurred: {e}")
    finally:
        robot.disconnect()
        robot.shutdown()


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Read target joint accelerations Synapse example")
    parser.add_argument("--ip", type=str, default=None,
                         help="UR robot IP address for real hardware, e.g. 192.168.1.100")
    parser.add_argument("--prim_path", type=str, default=None,
                         help='Isaac Sim articulation prim path, e.g. "/World/ur10e"')
    args = parser.parse_args()

    main(ip=args.ip, prim_path=args.prim_path)

Running the Example

Virtual

python get_target_joint_accelerations.py

Isaac Sim

python get_target_joint_accelerations.py --prim_path /World/ur10e

Real

python get_target_joint_accelerations.py --ip 192.168.1.100

For all options:

python get_target_joint_accelerations.py --help

Parameter Configuration

This skill takes no input parameters.

Returns

Type	Description
list[float]	Controller-commanded joint accelerations in deg/s², one value per joint, ordered base to wrist. Zero-filled offline.

Where to Use the Skill

• Trajectory analysis - Monitor the acceleration profile generated by the trajectory planner.
• Feedforward control - Read commanded accelerations for model-based control design.
• Jerk monitoring - Differentiate target accelerations to estimate jerk during motion.

When Not to Use the Skill

• You need the measured joint torques - use Get Joint Torques instead.