Open Gripper

SUMMARY

Open Gripper commands a parallel gripper to move to its fully open position.

This skill is used to release a grasped object or prepare the gripper for approach before a pick operation.

SUPPORTED GRIPPERS

Available on Robotiq and OnRobot grippers.

UNITS

speed / force in the configured speed and force units (default percent for Robotiq; OnRobot ignores speed and uses N for force).

The Skill

status = gripper.open(speed=100.0, force=100.0, asynchronous=False)

The Code

Example: Open to Release an Object

"""
Robotiq open example for the Synapse SDK.

Opens the gripper fully at 100% speed and 50% force, synchronously.

Usage:
    python open.py --ip <ROBOT_IP>
"""

import argparse
from loguru import logger

from telekinesis.synapse.tools.parallel_grippers import robotiq


def main(ip: str):
    """Open the gripper fully at 100% speed and 50% force."""

    # Create and connect to the gripper
    gripper = robotiq.Robotiq2F85()
    gripper.connect(ip=ip)

    try:
        status = gripper.open(speed=100.0, force=50.0, asynchronous=False)
        logger.success(f"open() status: {status}, position: {gripper.get_current_position():.2f}")
    finally:
        gripper.disconnect()


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Robotiq gripper open 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

open commands the gripper to move its fingers to the fully open position (the stroke set by set_position_range_mm). The call blocks until the gripper stops when asynchronous=False, or returns "MOVING" immediately when asynchronous=True.

Speed. Expressed in the configured speed unit (default: percent, 0-100). Pass -1.0 to use the session default set by set_speed.

Force. Expressed in the configured force unit (default: percent, 0-100). Pass -1.0 to use the session default set by set_force.

Return Values

Status	Description
"MOVING"	Returned when asynchronous=True
"AT_DEST"	Fingers reached fully open position
"STOPPED_OUTER_OBJECT"	Robotiq only - stopped against an external object. OnRobot hardware cannot distinguish inner from outer grip, so this value is never returned by OnRobot.
"STOPPED_INNER_OBJECT"	Robotiq: stopped by internal contact. OnRobot: any detected grasp (the hardware does not distinguish inner from outer).
"UNKNOWN_STATUS_<code>"	Unexpected hardware status

How to Tune the Parameters

Robotiq 2F-85

Parameter	Type	Default	Description
speed	float	100.0	Motion speed in percent (0-100). Pass -1.0 to use the session default.
force	float	100.0	Opening force in percent (0-100). Pass -1.0 to use the session default.
asynchronous	bool	False	If True, returns "MOVING" immediately without waiting.

OnRobot RG2 / RG6

Parameter	Type	Default	Description
force	float	-	Opening force in Newtons, clamped to the model's max force.
asynchronous	bool	False	If True, returns "MOVING" immediately without waiting.

Where to Use the Skill

• Release after place - Open the gripper after depositing an object
• Pre-approach clearance - Open fully before descending onto a pick target
• Reset state - Open at script start to ensure a known initial position

When Not to Use the Skill

Do not use Open Gripper when:

• Partial opening is required - use Tool Move to move to a specific intermediate position
• The gripper is not connected - always call connect before issuing motion commands