A high force haptic system for knee arthroscopy training

` This paper presents a novel four degree of freedom haptic system for virtual reality knee arthroscopy training. The compact device, named OrthoForce, has a large workspace and force feedback in all axes (yaw, pitch, roll and translation). The robust device uses a novel haptic rendering algorithm to provide smooth haptic response at multiple simultaneous contact points anywhere along the tool (including twist feedback with the hook). It is capable of displaying high impedances that realistically simulate the impact with hard objects. In particular, the novel use of a ball screw spline provides a maximum impedance of 20 N/mm for translation as well as roll torque feedback in a small structure. Not only does this device meet the requirements for haptic use in knee arthroscopy training, but due to its small size and large range of motion, it has applications in other virtual reality training systems for a range of minimally invasive procedures.