A Disturbance in the Force: Force Actuation on the RAVEN II Surgical Robot with Parallel Motor-Cable Units

2026-08-06

AI Summary

This study addresses the longstanding lack of effective haptic feedback in surgical robots and the challenge of acquiring high-quality training data under representative external forces without adding sensors. To this end, the authors propose a non-invasive, six-degree-of-freedom parallel motor-cable system arranged around the workspace of the RAVEN II surgical robot. By applying precisely controlled cable tensions to the robot’s end-effector, the system delivers accurate external forces without impeding its motion. The framework integrates custom motor hardware, a tension control algorithm, sensor drivers, and a simulation module, enabling—for the first time—high-precision force application using a parallel cable-driven architecture. Experimental results demonstrate a force control error of less than 1 N, providing high-fidelity training data for force-perception learning in robotic surgery.

Abstract

Difficulty in haptic feedback for surgical robots has been a long-term problem for decades. In recent years, learning-based force estimation from robot states suggests desirable accuracy without the necessity of extra sensors. However, challenges remain in obtaining representative training data in which the robot moves in the workspace under various external forces. In this work, a parallel motor-cable system is developed. With six motor-cable units installed around the robot workspace, cables with controllable tension connected to the robot end-effector can provide the desired external force without interfering with the movement of the surgical robot. The development of the system includes motor-unit hardware, control software, sensor drivers, simulations, and more. Preliminary experiments suggest an accuracy of force actuation with errors less than 1 N.

Problem

• surgical robot
• force estimation
• haptic feedback
• external force
• training data

Innovation

• force actuation
• parallel motor-cable system
• surgical robot
• haptic feedback
• RAVEN II