Get Joint Velocities

SUMMARY

Get Joint Velocities returns each joint's current angular velocity in deg/s, ordered base to wrist. Reads from the manipulator state - live values when connected, zero-filled offline.

SUPPORTED ROBOTS

Available on all supported manipulators in offline mode. Live hardware readings are currently supported only on Universal Robots.

UNITS

Returns joint velocities in deg/s, ordered base to wrist.

The Skill

joint_velocities = robot.get_joint_velocities()

The Code

"""
Read actual joint velocities example for the Synapse SDK.

Returns the manipulator's measured joint velocities [deg/s]. With ``--ip``,
reads live hardware state. Without ``--ip``, reads from the internal
commanded cache (no connection made) and logs a warning.

Illustrated using Universal Robots (UR10e), supported on all robots.

Usage:
    python get_actual_joint_velocities.py [--ip <ROBOT_IP>]
"""

import argparse
from loguru import logger

from telekinesis.synapse.robots.manipulators import universal_robots


def main(ip: str | None = None):
    """Log the current joint velocities [deg/s]."""

    robot = universal_robots.UniversalRobotsUR10E()

    if ip is not None:
        robot.connect(ip=ip)
    else:
        logger.warning(
            "No --ip provided; reading offline commanded-cache state, "
            "not live hardware readings."
        )

    try:
        logger.success(f"joint_velocities [deg/s]: {robot.get_joint_velocities()}")
    finally:
        if ip is not None:
            robot.disconnect()


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Read joint velocities Synapse example")
    parser.add_argument("--ip", type=str, default=None, help="UR robot IP address (optional)")
    args = parser.parse_args()

    main(ip=args.ip)

The Explanation of the Code

from telekinesis.synapse.robots.manipulators import universal_robots

robot = universal_robots.UniversalRobotsUR10E()

Create the robot. UR10e is used here for illustration; the same pattern works for every supported brand.

if ip is not None:
    robot.connect(ip=ip)

Connect to the robot at the given IP. When no --ip is passed, no connection is made and the getter returns from the offline commanded-cache (zero-filled) instead of live hardware.

logger.success(f"joint_velocities [deg/s]: {robot.get_joint_velocities()}")

Read the measured joint angular velocities in deg/s, ordered base to wrist. When connected this is the live controller value; offline the cache is zero-filled.

finally:
    if ip is not None:
        robot.disconnect()

Always release the controller link in a finally block so a failure mid-read still cleans up the connection.

Return Value

Type	Description
list[float]	Current joint velocities in deg/s, one value per joint, ordered base to wrist. Zero-filled offline.

Where to Use the Skill

• Motion monitoring - Detect when the robot is decelerating or at rest.
• Velocity-based control loops - Use current velocity as feedback input.
• Dynamics logging - Record velocity profiles alongside position data.

When Not to Use the Skill

• You need TCP speed - use Get TCP Speed for end-effector velocity.
• You need joint positions - use Get Joint Positions instead.