Control of FES standing

Following our earlier work we are developing the controller system for unsupported standing of human. Body is considered as a double inverted pendulum, activated with ankle plantar and dorsiflexor muscles via Functional Electrical Stimulation. The volunteers for the experiments are intact subjects standing in modified Mechanical Rotating Frame, which braces all joints and provides isometrical conditions. In this was first examined RARX ankle plantarflexor muscle identification, which gave us insight into muscle parameter variation during one experimental trial. Instead of controller parameter adaptation, we decided for design with robust feedback and scheduled feedforward controllers in moment control loop. The results: (i) show degree of change in muscle parameters during PRESS identification trial; (ii) that is tracking performance of new structure superior to the previously studied and published LQG design.