Physiological musculoskeletal model identification for the lower limbs control of paraplegic under implanted FES

This paper concerns the whole physiological parameters identification of a musculoskeletal model of a human subject. The patient is equipped with an implanted Functional Electrical Stimulation (FES) system as part of the SUAW's European project. The biomechanical model represents the knee and its associated muscles. The identification protocol is noninvasive and based on the in-vivo experimental data acquisition of a Spinal Cord Injured (SCI) patient. However, the human noninvasive identification poses problems of inaccessibility to some data. The identification procedure consists of several steps, in order to identify: the anthropometrical parameters, the geometrical parameters, the joint mechanical parameters, the force-length relationship and the recruitment function. Up to now, only the quadriceps muscle is considered with the knee joint in the identification procedure. A cross-validation has been done using data set not used during the identification process. The identified model shows a satisfactory response comparing to the measured knee response, which is obtained by stimulating the quadriceps through the implanted FES system. In this work, knee model-parameters of the implanted subject were identified successfully using the noninvasive identification procedure.