Utilising Incipient Slip for Grasping Automation in Robot Assisted Surgery

Abstract

Despite recent advances in modern surgical robotic systems, an ongoing challenge remains their limited ability to control grasp force. This can impair surgical performance as a result of either tissue slippage or trauma from excessive grasp force. In this work we investigate a force control strategy to address this challenge based on the detection of incipient slip. Our approach employs a grasper face whose shape is engineered to encourage preferential localised slips that can be sensed using embedded displacement sensors prior to gross slip occurring. This novel approach enables closed loop control of the grasping force to prevent gross slip whilst applying minimal force. In this paper we first demonstrate the efficacy of sensing incipient slip and then demonstrate how this can form a robust closed loop grasping system to maintain stable control of tissue. Results demonstrate that this approach can achieve equivalent grasping performance to a scheme employing a fixed maximal grasping force while reducing tissue loading, and thus risk of trauma. This provides the foundation for the development of automated surgical robots with adaptive grasp force control.