ELECTRICAL STIMULATION OF LIMBS - 3. JOINT POSITION CONTROL.

This paper describes the modeling and the position-control of a single-degree-of-freedom joint by means of pulse-width modulation of the signal sent to the agonist muscle's nerve. The first part presents an experimental procedure devised from the previous results of this study. In the second part, the mathematical methods used in order to identify the process and to analyze the results obtained are concisely shown. The control law of a physical system must define a realistic mathematical model of the process and also provide a model simple enough to be useful. The proposed model satisfies these two criteria. The results of the simulation show that, with a single stimulation signal, the actual and the simulated outputs behave in an identical manner. Hence, the identification procedure has provided a sufficient estimation of the parameters of the system, thus obviating the necessity of determining biomechanical constants by complex and inaccurate measurements.