Virtual Bone Surgery Using a Haptic Robot

Article history: Received: August 15, 2009. Received in revised form: November 24, 2009. Accepted: November 29, 2009. This paper describes a virtual reality (VR)-assisted robotic surgery simulator for bone surgery training. A trainee surgeon holds the haptic robot stylus and manipulates it three-dimensionally to interact with the virtual bone. The robotic simulator allows the trainee surgeon to feel the machining force and to see the bone removal in real-time. To make the virtual world feel real, this work incorporates a physics-based force model of bone machining process to calculate tool-bone interaction forces. The physics-based model considers chip formation process and includes main machining parameters such as feed rate and tool geometry. Real-time force feedback is provided to the user via a fast voxel-based collision detection and response algorithm. A multi-rate haptic rendering approach is used to interpolate forces between consecutive updates and to send force commands to the haptic robot at a sufficiently high-rate. A volumetric visual rendering technique is also described to display the bone volume and removal of bone material during machining. The simulator utilizes voxel information from bone CT scan of real patients. The real-time implementation of the method in a dental training simulator is described using a 6-DOF haptic robot. Virtual machining force results are presented for a surface machining operation.