Wearable Goniometer and Accelerometer Sensory Fusion for Knee Joint Angle Measurement in Daily Life.

Area of Science:

• Biomechanics
• Wearable Technology
• Sensor Fusion

Background:

• Accurate human motion analysis is vital across many fields.
• Low-cost, unobtrusive sensing for ambulatory motion detection remains a challenge.
• Inertial measurement systems and e-textiles offer promising solutions for everyday monitoring.

Purpose of the Study:

• To develop and evaluate an innovative sensing system combining e-textiles and tri-axial accelerometers.
• To create a robust sensory fusion method for ambulatory human motion analysis.
• To assess the system's performance in measuring knee joint angles during various activities.

Main Methods:

• Developed a novel sensing concept integrating e-textiles and tri-axial accelerometers.
• Implemented a Kalman filter-based sensory fusion technique.
• Combined outputs from textile electrogoniometers and accelerometers without initial position assumptions.
• Measured knee flexion-extension angles during monopodalic flexions and walking.

Main Results:

• The system demonstrated reliable performance, benchmarked against a commercial inertial measurement unit system.
• Achieved a low root mean square error (mean: 1.96°, std dev: 0.96°).
• Showed significant improvement in angular estimation compared to using individual sensors.

Conclusions:

• The developed e-textile and accelerometer system offers a reliable and accurate method for ambulatory human motion analysis.
• The sensory fusion approach enhances joint angle estimation.
• Future work will involve extending the method to more complex joint movements.