Haptic body-powered upper-extremity prosthesis simulator with tunable stiffness and sensitivity

In this paper, we present the design, implementation, and characterization of a haptic body-powered prosthesis simulator. A novel aspect of our design is enabling real-time adjustment of gripper stiffness and control cable sensitivity parameters via software based on a haptic teleoperation control algorithm. Adjustment of these parameters across a continuum of values can assist the user to decide on the optimal parameters that can best fulfill the user´s functional needs, rendering the device a body-powered prosthesis prescription tool. Additionally, a switching capability between the voluntary-closing (VC) mode and the voluntary-opening (VO) mode is incorporated into the software interface. With design and operation characteristics that closely replicate the form and mechanics of an actual body-powered upper-extremity prosthesis, our haptic prosthesis enables parameter optimization for individual prosthesis users and various human-subject-based research experiments involving both amputees and non-amputees on task-based optimization of prosthesis parameters and selection of operation mode.