Volitional EMG Control Enables Stair Climbing with a Robotic Powered Knee Prosthesis

Area of Science:

• Biomedical Engineering
• Robotics
• Rehabilitation Technology

Background:

• Current robotic prostheses use predefined trajectories, limiting user volitional control.
• Restoring natural, intuitive control is crucial for amputee mobility.
• Existing systems lack direct user command integration for complex movements like stair climbing.

Purpose of the Study:

• To develop and evaluate a proportional electromyographic (EMG) control system for powered knee prostheses.
• To enable direct volitional control of prosthetic knee torque during stair climbing.
• To enhance prosthetic functionality and improve real-world mobility for above-knee amputees.

Main Methods:

• Implemented a proportional EMG controller using residual hamstring muscle activation measured by a single socket-integrated EMG electrode.
• Mapped EMG signals to desired knee flexion/extension torque, considering prosthesis position and ground interaction.
• Tested the system with an above-knee amputee performing stair climbing tasks.

Main Results:

• The EMG controller enabled volitional control of the powered knee prosthesis during stair climbing.
• The amputee could ascend stairs at varying speeds, carry loads, and even climb backwards.
• Demonstrated continuous regulation of knee torque based on real-time EMG signals.

Conclusions:

• Proportional EMG control offers direct, volitional control for powered knee prostheses.
• This technology has significant potential to improve amputee mobility and functional independence.
• The system provides a more intuitive and responsive user experience compared to traditional controllers.