Force-Moment Sensor for Prosthesis Structural Load Measurement

Area of Science:

• Biomechanics
• Biomedical Engineering
• Sensor Technology

Background:

• Prosthesis structural load measurement is crucial for smart lower-limb prosthetic control.
• Existing strain gauge sensors suffer from weak signals and drifting, limiting their effectiveness.
• Novel sensor development is needed to overcome these limitations.

Purpose of the Study:

• To present a novel Force-Moment Prosthesis Load Sensor (FM-PLS) for measuring axial force and bending moment.
• To address limitations of traditional strain gauge sensors in prosthetic applications.
• To enable more robust and reliable control of lower-limb prosthetics.

Main Methods:

• Developed a novel FM-PLS using magnetic sensing of elastic element deflection.
• Designed the sensor with curved supporting surfaces for sensitivity and robustness.
• Validated performance through benchtop testing and walking experiments with an embedded robotic prosthesis.

Main Results:

• Benchtop tests showed good linearity and matched numerical simulations.
• The FM-PLS provides stronger signals, robust against interference and drifting.
• Walking experiments demonstrated detection of gait events like heel strike and toe-off.

Conclusions:

• The FM-PLS offers a promising alternative to strain gauge sensors for lower-limb prosthetics.
• The sensor's ability to detect gait events facilitates reliable motion control.
• This technology can significantly advance the development of smart prosthetic devices.