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Feedback control of electrically stimulated muscle using simultaneous pulse width and stimulus period modulation
H J Chizeck1, N Lan, L S Palmieri
1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106.
IEEE Transactions on Bio-Medical Engineering
|December 1, 1991
Summary
This study introduces a new control method for electrically stimulated muscles using combined pulse width and frequency modulation, improving muscle force regulation for neural prostheses.
Area of Science:
- Biomedical Engineering
- Neuroscience
- Rehabilitation Engineering
Background:
- Previous research demonstrated effective muscle force control using pulse width modulation (PWM) with adaptive controllers.
- Limitations in transient response control and pulse efficiency were noted with PWM alone.
Purpose of the Study:
- To enhance closed-loop control of electrically stimulated muscle by combining pulse width and frequency modulation.
- To develop a single-input controller for both single muscle activation and antagonist co-stimulation.
- To improve transient response, stability, and pulse efficiency compared to PWM-only methods.
Main Methods:
- Developed a hybrid controller integrating pulse width modulation (PWM) and pulse frequency modulation (PFM).
- Implemented reciprocal frequency modulation for antagonist co-stimulation.
- Evaluated controller performance in animal experiments under various conditions.
Main Results:
- Combined PWM and PFM improved transient responses in single muscle activation.
- Reciprocal frequency modulation in co-stimulation enhanced stability and speed with fewer pulses.
- Achieved rapid rise times without overshoot, demonstrating robust performance across different parameters and subjects.
Conclusions:
- The combined PWM and PFM controller offers superior performance for muscle stimulation.
- This advanced control strategy shows significant promise for restoring functional movement in individuals with paralysis via neural prostheses.