Reduction of Parkinsonism disorder symptoms using passive dual absorbers

Passive vibration absorber can be used as an effective device for tremor reduction of the involuntary tremor at proximal joints in hand of elderly patients suffering from Parkinsonism. Dual vibration absorber are suggested to reduce the Parkinson's tremor of a dynamic hand system excited using two harmonic excitation resonance frequencies in range of resting tremor. The three degree of freedom hand is actuated by the shoulder, elbow and wrist joint muscles activation to produce the involuntary flexion motion. The dual parallel conventional absorber and the dual series absorber which is modeled as an elastic absorber and viscous damper connected in series are designed to satisfy the tuning condition at both resonance frequencies. The dual parallel absorber reduces 57.0–82.5%, 51.6–76.9% and 26.6–62.0% of the flexion motion at the shoulder, elbow and wrist joints in the time domain, respectively. The dual series absorber reduces 82.6–97.3%, 77.24–84.2% and 33.0–62.0% of the flexion motion at the shoulder, elbow and wrist joints in time domain, respectively. Both absorbers are very useful in controlling the rest tremor and can be used by elderly patients instead of medications which may risk their lives.