Direct and indirect methods to optimize the muscular force response to a pulse train of electrical stimulation

Recent force-fatigue mathematical models in biomechanics [7] allow to predict the muscular force response functional electrical stimulation (FES) and leads optimal control problem of maximizing force. The stimulations are Dirac pulses parameters amplitudes times application, number is physically limited model a sampled data problem. aim this article present compare two methods. first method direct optimization scheme where further refined numerical discretization applied on dynamics. second an indirect scheme: first-order Pontryagin type necessary conditions derived used compute sampling times.