Adaptive control of the nonlinearly parameterized limb dynamics with application to neuromuscular electrical stimulation

This paper considers the lower leg limb motion tracking problem that is inherent to neuromuscular electrical stimulation systems. We propose an adaptive controller that compensates for the unknown parameters that appear nonlinearly in the mechanical dynamics. This is accomplished by exploiting the Lipschitzian properties of nonlinearly parameterized functions. The resulting discontinuous control law ensures asymptotic tracking for the lower leg limb angular position without violating its physical limits. Simulations demonstrate the control performance.