Human-FES Cooperative Control for Wrist Movement: A Preliminary Study

Area of Science:

• Biomedical Engineering
• Neurorehabilitation
• Control Systems

Background:

• Partial paralysis often necessitates functional electrical stimulation (FES) alongside voluntary movement.
• Existing FES systems may not fully integrate with residual human motor control.
• Optimizing FES control is crucial for improving patient function and reducing reliance on external devices.

Purpose of the Study:

• To develop and evaluate a cooperative controller for enhanced human-FES interaction.
• To reduce FES intensity by leveraging volitional control.
• To improve the functional outcomes for individuals with partial paralysis.

Main Methods:

• A cooperative controller was designed, combining a classical FES controller (BP neural network feedforward and PID feedback) with an impedance controller.
• The impedance controller translates volitional force/torque, estimated via a three-stage EMG-based filter, into an additional angle.
• Assessment experiments were conducted to evaluate the cooperative controller's performance.

Main Results:

• The cooperative controller demonstrated the ability to reduce FES intensity compared to classical FES control.
• Integration of volitional torque estimation effectively contributed to FES modulation.
• Experimental results validated the controller's efficacy in a human-FES cooperation scenario.

Conclusions:

• The developed cooperative controller successfully integrates human voluntary control with FES.
• This approach offers a promising method for reducing FES intensity and improving rehabilitation outcomes.
• Further research can explore advanced control strategies for more intuitive and effective human-machine synergy in neuroprosthetics.