Grasped object stiffness detection for adaptive PID sliding mode position control of a prosthetic hand

A PID sliding mode position controller and an adaptive sliding mode controller are presented for a prosthetic hand. The adaptive controller modulates the PID gains based on the detected stiffness of the grasped object. The results from benchtop experiments indicate statistically significant improvements such as improved tracking error and reduced steady state error in the system response when using the adaptive controller.