Sensorless Based Gravity Torque Estimation and Friction Compensation for Surgical Robotic System

This article intends to provide content that is both basic and elementary, but at the same time discusses how solving difficult challenges when estimating the actual force in real-time teleoperation using a small-size DC motor as the end effector/ gripper of the surgical robot. The end-effector of the surgical robot, where the surgical tools have been attached, requires high-end precision. Most commercial surgical robotic systems calculate the real-time force by using traditional force sensors which encounters hindrance like lack of expected response (advance control), limited bandwidth, and requirement of force for its own operation. The paper introduces a Disturbance observer (DOB) based Reaction Torque observer (RTOB) as the sensor for the real-time gravity torque sensing in biomedical applications, with a focus on surgical robots. In order to enable both professional engineers and students with a limited understanding of control to use the article, mathematical complications are kept to a minimum.