Parametric evaluation and optimization of a novel see-saw actuator for tremor attenuation

Tremors are defined as low to medium-frequency oscillations of the human limbs. These tremors are typically a result of chemical imbalances in the brain that lead to involuntary or uncontrolled voluntary movements of the human arm. Numerous medical treatments have been devised to control tremors, but they can be unsuccessful and expensive, with some undesirable side effects in the long run. This paper introduces a passive actuator capable of attenuating tremors over a wide range of frequencies while being lightweight and small in size. The tremors are modelled as harmonic vibrations, and the arm is modelled as a lumped mass for the shoulder flexion-extension degree of freedom. The device produces <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>99.34</mml:mn><mml:mi>%</mml:mi></mml:math> tremor reduction at resonance and an average tremor reduction of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mn>55</mml:mn><mml:mi>%</mml:mi></mml:math> between 0.8 and 8Hz.