Method for Sensing Lateral Force and Skidding on the Tool Tip in Surgical Robot Deep Bone Drilling *

Abstract

Bone drilling is a critical component of many clinical surgeries. In robot-assisted deep bone drilling procedures, the complex structure of bone tissue and individual variations in drilling paths often cause slender tools to skid on personalized bone surfaces, leading to deviations that significantly impact surgical precision and safety. This paper presents the development of an orthopedic surgical robot equipped with skidding sensing capabilities. A novel sensing solution for the bone drilling unit is proposed, which employs rigid body force transmission and decouples thrust and lateral force sensing. This approach addresses the challenge of acquiring force information from the deep tool tip within the body. We also introduce a tool tip skidding estimation method based on the deflection curve model and the Spatial-Beam Constraint Model (SBCM). A specialized simulation device for measuring tool tip offset and force was designed. The experimental results demonstrate that the system achieves average sensing errors of 31.8 mN and 43.5 mN for lateral forces at the tool tip along the X and Y directions, respectively. Additionally, the system's resolution for skidding estimation reaches 0.2 mm. Real bone drilling experiments confirm the system’s ability to effectively provide feedback on skidding during surgery. The proposed method enhances the safety of orthopedic surgical robots and offers crucial sensing information for lateral forces and skidding, paving the way for future autonomous bone drilling procedures.