A Tremor-Suppressing Strategy Based on the Equivalent-Input-Disturbance Approach

Tremor is a rhythmical and involuntary oscillatory movement of a body part, and it is one of the most common movement disorders. Exoskeleton-assisted movements have been investigated as a noninvasive method of tremor suppression as an alternative to medication or surgery. The challenge in tremor suppressing is to attenuate a tremor motion without interfering with a patient's voluntary movements. This study devised a tremor-suppressing strategy for patients with pathological tremors. First, a polytopic system describes a wrist-exoskeleton system with parameter uncertainties. Next, a control system uses the equivalent-input-disturbance (EID) approach for tremor suppression. Then, we present a method of designing a control law employing EID estimation. Finally, simulation and experimental results demonstrate the validity of the method.