Abstract
The human-prosthesis systems for force control may be regarded as the man-machine control systems, in which the manipulated variables are driven by EMG signals and the display information is given by electrocutaneous stimulations. Progress in prostheses requires a clearer understanding of the human operator's characteristics and developments of the more intimate interface between amputee and prosthesis based on his characteristics.
This paper analyzes the human operator's dynamic characteristics in human-prosthesis systems by a series of simulated experiments. First, it is shown that the operator's phase lag caused by the electrocutaneous stimulation is longer than the one in regular man-machine systems and that the cross-over model does not hold. From such results, a human-prosthesis interface with the Smith controller is proposed. The Smith controller can compensate the operator's dead time and improve system stability. The experimental results demonstrate that the system performance can be improved largely and a operator's load could be reduced.
