The use of the principle of feedback scheduling for enhancing the real-time paraplegic knee response

In this work we simulate the behavior of the knee movement in ideal case of a paraplegic subject in closed loop by implementing a PID controller. We are interested in the response of the knee angle by taking into account real-time constraints. First, we used the Ferrarin and Pedotti´s model. Then, the knee FES application has been decomposed in three real-time tasks in such a way that two tasks execute the control and the third one calculates the parameters of control used by the two first tasks. The three tasks were executed by a real-time kernel employing Feedback Scheduling which is a sampling period selection for limited computing resources. As results, by satisfying the realtime constraints of the tasks and by reaching good processor utilization the knee response improved significantly.