Real-time Algorithm for Detection of Breakthrough Bone Drilling

The purpose of this study is to develop a force control algorithm that detects breakthrough of drill bit during bone drilling process, where the drilling process will halt and return to a safe position once the algorithm is triggered. Orthopaedic surgery in traditional practices does not equipped with any means of detection method to detect the breakthrough in drilling process. It mostly depends on the surgeon's experience and skills when conducted the operation. The algorithm is built using Simulink model under Matlab software and implemented on WinCon software to run under real-time process. The breakthrough algorithm detects the differences of sharp drop force in z-direction and calibrates the force in tri-axial direction as the threshold value. The system is verified through an experiment drilling cow femur bone using 5 DoF CRS Catalyst-5 robots. Preliminary drilling test is conducted to observe the sharp drop in the force value which is to be the threshold force. This will help to increase the safety enhancement during drilling process cause by drill bit breakage, unnecessary drill bit breakthrough, excessive heat generation, and mechanical damage to the bones caused by uncontrolled and large forces.