PID Control Design for Rehabilitation by Quasi-isometric Training in Paraplegia: A Simulation Study

This paper reports simulation results about the design of a PID controller of Functional Electrical Stimulation (FES) to be used for quasi-isometric exercises in rehabilitation of paraplegics. The simulations refer to a specific seesaw device developed at the Fondazione Don Gnocchi, mainly used in standing up and sitting down using FES. The design of feedback controllers for such a device is currently based on nonlinear strategies. These are necessary when aiming to standing and sitting control. However, there is a strong demand by rehabilitation physiotherapists for easy-to-tune controllers, even though these could be used only in specific conditions. So, a PID linear controller has been designed and tested by means of simulations. The controller tuning is performed by using four different methods specifically designed for unstable systems with delay.