Control and breakthrough detection of a three-axis robotic bone drilling system

This paper describes a robotic bone drilling system for applications in orthopedic surgery. The goal is to realize a three-axis robotic drilling system which can automatically stop drilling at the moment a drill breaks through bone. The proposed robotic bone drilling system consists of an inner loop fuzzy controller for robot position control, and an outer loop PD controller for feed unit force control. Moreover, breakthrough detection is a function of thrust force threshold information and trends in drill torque and feed rate. The proposed technique has been verified by drilling pig bones, the results for both the bone drilling and bone breakthrough processes are in accord with theoretical model.