Study On Suppressing Tremor In Wrist Joint Using Functional Electrical Stimulaton

Functional Electrical Stimulation (FES) is a useful method whichachieves the goal of restoring motor function of paralyze limb throughsurface electrodes. Pathological tremor is a common disease in elders,which is a kind of rhythmic shaking motion of a body part. Tremor isusually involuntary. We aim to design an assistive system for suppressingtremor in wrist joint using FES.Our research consists of signal processing, controller design,simulation study and experimental verification. First of all, we developed amusculoskeletal model of wrist joint based on Hill-type muscle model in1-DOF and3-DOF respectively. And the model was proved to bemeaningful through FES experiments later. Then, the design of controllersfor suppressing wrist’s tremor was conducted in Simulink environment ofMatlab. The PID controller was used for attenuating wrist tremor in1-DOF,while the LQR controller was recruited to suppress the wrist tremor in3-DOF. Simulation results suggest that both controllers can make thesystem’s output to follow the desired low frequency input (voluntarymotion) well and eliminate the high frequency disturbances (tremor). Inthe end, the experimental platform for suppressing tremor using FES wasset up. Clinical data were collected on patients in Ruijin Hospital, whichwere analyzed and used for system design. Experiments were performedon both healthy subjects and Parkinson’s subjects. The satisfactory resultsverified the feasibility of the system.