Non-contact capacitance sensing for continuous locomotion mode recognition: design specifications and experiments...

Area of Science:

• Biomedical Engineering
• Rehabilitation Engineering
• Prosthetics and Orthotics

Background:

• Locomotion mode recognition is crucial for advanced prosthetic limb control.
• Existing methods may face challenges with signal quality and non-contact measurement.
• Powered lower-limb prostheses require sophisticated systems for seamless integration with users.

Purpose of the Study:

• To introduce and evaluate a non-contact capacitance sensing system (C-Sens) for measuring interfacial signals.
• To assess the system's effectiveness in recognizing various locomotion modes for prosthetic control.
• To determine the accuracy of the C-Sens system in classifying gait phases.

Main Methods:

• Developed a non-contact capacitance sensing system (C-Sens) with electrodes inside the prosthetic socket.
• Integrated foot pressure insoles for gait phase detection and a control circuit for data sequencing.
• Conducted experiments with a transtibial amputee, recording seven locomotion modes.
• Utilized a continuous phase-dependent classification method and Quadratic Discriminant Analysis (QDA) classifier.

Main Results:

• The C-Sens system achieved high average recognition accuracies: 93.8% for the stance phase and 95.0% for the swing phase.
• The system successfully recorded and differentiated between seven distinct locomotion modes.
• Interfacial signals between the residual limb and socket were effectively measured by the capacitance sensors.

Conclusions:

• The C-Sens system demonstrates significant potential for enhancing the control of powered lower-limb prostheses.
• Non-contact capacitance sensing offers a viable approach for reliable locomotion mode recognition.
• Accurate gait phase classification using C-Sens can lead to more intuitive and responsive prosthetic function.