Force control and breakthrough detection of a bone drilling system

Because neurosurgery and orthopedic surgery often require the drilling of bones, this paper attempts to solve the problem of bone drilling. The goal is to realize a control system, which is able to drill with a contact drilling force and can automatically stop drilling at the moment of breaking through. In particular, both the DC drilling motor control and the feed rate control are driven by force control in order to accommodate the system impedance. Moreover, the breakthrough detection is according to the threshold information of the thrust force as well as the trend of both the drilling torque and feed rate. The proposed technique has been experimentally verified through the drilling of pig bones, and the results are in accordance with the theoretical model both in the bone drilling process and at the point of breakthrough.