Control of standing and gait using electrical stimulation: influence of muscle model complexity on control strategy

Three approaches to controlling standing and gait in paraplegics through functional electrical stimulation are presented. The approaches differ in their requirements for modeling the muscle actuator. The first approach describes a detailed muscle model and presents methods for rapid experimental parameterization of the model. The second requires a less detailed model and knowledge of model error bounds to design advanced, non-linear controllers which guarantee stability. The third approach needs no muscle model since it controls limb trajectories through combining stimulation with an orthosis containing controllable friction brakes at the joints. Future clinical systems may use one or a combination of these approaches to restore useful function.