Cadence Tracking for Switched FES Cycling Combined with Voluntary Pedaling and Motor Resistance

摘要

A wide variation in muscle strength and range of motion exists in the movement disorder rehabilitation community. Functional Electrical Stimulation (FES) can be used to induce muscle contractions to assist a person who can contribute volitional coordinated torques. A motor can be used to both assist and resist a person's volitional and/or FES-induced pedaling. In this paper, a multi-level switched system is applied to a two-sided control objective to maintain a desired range of cadence using FES, motor assistance, motor resistance, and volitional pedaling. A system with assistive, passive, and resistive modes are developed based on cadence, each with a different combination of actuators. Lyapunov-based methods for switched systems are used to prove global exponential tracking to the desired cadence range for the combined FES-motor control system. Preliminary experiments show the feasibility and stability of the multi-level switched control system.