Gripper Set Force

SUMMARY

Set Force configures the default gripping force. Call set_force only when a different session-level default is needed.

UNITS

force in the configured force unit (default percent for Robotiq, N for OnRobot).

The Skill

actual_force = gripper.set_force(force=60.0)

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.

Real

"""
Demonstrates setting the default grip force of a parallel gripper.

Supports OnRobot and Robotiq grippers, and Isaac Sim.

Usage:
    python set_force.py --ip <GRIPPER_IP>
    python set_force.py --prim_path <PRIM_PATH>

Note:
    The simulation does not model grip force, so in Isaac Sim this call is
    accepted but has no effect on the motion.

    Experimental gripper support for Isaac Sim:  Robotiq 2F85 (USD-based simulation only); Schunk EGP and
    PZN+ are.
"""

import argparse
from loguru import logger

from telekinesis.synapse.tools.parallel_grippers import onrobot


def main(ip: str | None,
         protocol: str,
         prim_path: str | None) -> None:
    """Sets the default grip force of an OnRobot gripper to 50 N."""

    #===================== Create Gripper ======================================
    gripper = onrobot.OnRobotRG6()

    try:
        #===================== Connect Gripper =================================
        if prim_path:
            gripper.connect(simulation_prim_path=prim_path)
        else:
            gripper.connect(ip=ip, protocol=protocol)

        # ==================== Run Skill ====================================
        actual = gripper.set_force(force=50.0)
        logger.success(f"Default force set; effective: {actual}")
    except (ConnectionError, OSError) as e:
        logger.error(f"Error occurred: {e}")
    finally:
        gripper.disconnect()


if __name__ == "__main__":
    p = argparse.ArgumentParser(description="OnRobot gripper set force")
    p.add_argument("--protocol",
                   choices=["MODBUS_TCP"],
                   default="MODBUS_TCP")
    p.add_argument("--ip", default=None, help="IP for OnRobot Gripper")
    p.add_argument("--prim_path", type=str, default=None,
                   help='Isaac Sim gripper prim path, e.g. "/World/onrobot_rg6"')
    args = p.parse_args()

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

Running the Example

Real

python set_force.py --ip 192.168.1.100

Isaac Sim

python set_force.py --prim_path /World/onrobot_rg6

For all options:

python set_force.py --help

Parameter Configuration

Robotiq 2F-85

Parameter	Type	Default	Description
force	float	required	Desired force in percent (0-100). Pass -1.0 to use the backend's current preset.

OnRobot RG2 / RG6

Parameter	Type	Default	Description
force	float	required	Desired force in Newtons. RG2 max 40 N, RG6 max 120 N. Pass -1.0 to use the backend's current preset.

Returns

Type	Description
float	The actual force value accepted by the backend.

Raises

Robotiq 2F-85

Exception	Condition
RuntimeError	The gripper is not connected

OnRobot RG2 / RG6

Exception	Condition
TypeError	force is not numeric

How to Tune the Parameters

Start with a low force (20-30% for Robotiq, or ~10 N for OnRobot) for lightweight or fragile parts and increase until the grasp is secure without risking damage.

Where to Use the Skill

• Session baseline - Set once after connecting so individual move/open/close calls can pass force=-1.0
• Force profile switching - Re-call mid-session when switching between object types that need different gripping forces

When Not to Use the Skill

Do not call set_force when:

• Force is passed per-call - if every move/open/close already includes an explicit force argument, this call is redundant
• The gripper is not connected - always call connect before issuing configuration commands