A passive admittance controller to enforce Remote Center of Motion and Tool Spatial constraints with application in hands-on surgical procedures

TL;DR

This paper introduces a passive admittance control method for surgical robots that enforces remote center of motion and spatial constraints, ensuring safety and stability during minimally invasive procedures.

Contribution

A novel passive admittance control scheme is developed to enforce motion constraints and safety regions in surgical robot manipulation, with proven stability and demonstrated effectiveness.

Findings

Ensures robot tool stays within safe spatial regions.

Maintains manipulation stability under human force.

Provides smooth, natural motion in surgical tasks.

Abstract

The restriction of feasible motions of a manipulator link constrained to move through an entry port is a common problem in minimum invasive surgery procedures. Additional spatial restrictions are required to ensure the safety of sensitive regions from unintentional damage. In this work, we design a target admittance model that is proved to enforce robot tool manipulation by a human through a remote center of motion and to guarantee that the tool will never enter or touch forbidden regions. The control scheme is proved passive under the exertion of a human force ensuring manipulation stability, and smooth natural motion in hands-on surgical procedures enhancing the user's feeling of control over the task. Its performance is demonstrated by experiments with a setup mimicking a hands-on surgical procedure comprising a KUKA LWR4+ and a virtual intraoperative environment.