Trigger Protective Stop

SUMMARY

Trigger Protective Stop commands the robot controller to enter a protective stop - the same state triggered by collision or safety boundary violations. All motion halts immediately; the robot remains powered but frozen until the stop is acknowledged from the teach pendant.

SUPPORTED ROBOTS

Currently supported only on Universal Robots.

The Skill

robot.trigger_protective_stop()

The Code

Safety first!

A real robot will faithfully do whatever you ask of it - so please take a moment to clear the workspace, keep an E-Stop within reach, and be ready to disconnect.

Operating real hardware is at your own risk.

Example: Trigger a Protective Stop

Connect to the robot and trigger a protective stop programmatically.

"""
Trigger protective stop example for the Synapse SDK.

Currently supported only for Universal Robots (UR10e).

Immediately halts all motion and puts the robot into a protective stop
state. The robot remains powered but frozen until the stop is
acknowledged and cleared from the teach pendant.

Usage:
    python trigger_protective_stop.py --ip <ROBOT_IP>
"""
import argparse

from loguru import logger

from telekinesis.synapse.robots.manipulators import universal_robots


def main(ip: str):
    """Trigger a protective stop on the controller."""

    # Create and connect to the robot
    robot = universal_robots.UniversalRobotsUR10E()
    robot.connect(ip=ip)

    # Trigger the protective stop and report
    try:
        robot.trigger_protective_stop()
        logger.success("Protective stop triggered.")

    # Ensure we disconnect even if there was an error
    finally:
        robot.disconnect()


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Trigger protective stop Synapse example")
    parser.add_argument("--ip", type=str, required=True, help="UR robot IP address")
    args = parser.parse_args()

    main(ip=args.ip)

The Explanation of the Code

trigger_protective_stop sends a stop command that puts the controller into a protective stop state. Unlike stop_cartesian_motion or stop_joint_motion, which decelerate motion gracefully, a protective stop halts the robot immediately regardless of speed. The robot remains powered and joint-locked. Recovery requires manually acknowledging the stop on the teach pendant before motion can resume. This method requires an active motion program to be running on the controller; calling it on an idle robot will raise an error.

How to Tune the Parameters

This skill takes no input parameters.

Return Value

Return Type	Description
None	Returns after the protective stop command is sent.

Where to Use the Skill

• Safety-triggered application-level stops when a sensor or vision system detects an imminent collision.
• Testing protective stop recovery procedures in a controlled environment.

When Not to Use the Skill

Use graceful motion stop methods instead:

• Use Stop Cartesian Motion or Stop Joint Motion for graceful motion interruption that does not require teach-pendant recovery.