Robust controller for tremor suppression at musculoskeletal level in human wrist

Area of Science:

• Biomedical Engineering
• Neuroscience
• Rehabilitation Technology

Background:

• Tremor is a common movement disorder affecting the upper limbs.
• Orthotic devices offer a noninvasive approach to tremor suppression.
• Accurately estimating and attenuating tremor without hindering voluntary movement is a key challenge.

Purpose of the Study:

• To develop and evaluate a robust tremor suppression algorithm for upper limb pathological tremor.
• To address the challenge of distinguishing and mitigating tremor from intentional motion.

Main Methods:

• A high-pass filter was used to estimate motion within the tremor frequency range.
• The backstepping control method was applied to calculate corrective torque, effectively estimating tremor torque.
• A human arm joint simulator was employed to experimentally validate the algorithm for Parkinsonian and essential tremors.

Main Results:

• The proposed algorithm demonstrated robust performance and system stability, even with uncertainties in the human arm model.
• Experimental results showed significant tremor suppression, ranging from 30-42 dB (97.5-99.2%).
• Minimal impact on the patient's intentional motion was observed.

Conclusions:

• The developed algorithm provides effective and robust tremor suppression for upper limb disorders.
• This noninvasive approach holds promise for improving the quality of life for individuals with pathological tremor.
• The study validates the efficacy of the backstepping method in orthotic device control for tremor reduction.