Switched control of mechanical systems by using musculotendon actuators

This paper addresses the problem of modeling, control, and simulation of a mechanical system actuated by an agonist-antagonist musculotendon subsystem. Contraction dynamics is given by case I of Zajac´s model. Saturated semi-positive PD-type controllers with switching as neural excitation inputs are proposed. Linear approaches of nonlinear systems, root locus, switched systems control and SOSTOOLS are used to determine the stability for the obtained closed-loop system. To corroborate the obtained theoretical results numerical simulations have been performed with help of Matlab.