Minimum sensor configuration for maximum gait event detection with a powered ankle-foot orthosis

This study investigated the minimum sensor configuration (individual or pair) to achieve the simplest cost-effective sensor fusion configuration for robust gait event detection. Five sensors were attached to a powered ankle-foot orthosis: foot IMU, shank IMU, ankle potentiometer, heel contact sensor, and toe contact sensor. Sensor signals were compared to motion capture data for five healthy young adults walking on an instrumented treadmill. A single IMU on the shank detected the most gait events during a gait cycle (eight out of ten). Our recommendation is to use a shank IMU and heel contact sensor as a failsafe feature for detecting nine out of ten gait events and for control of a powered ankle-foot orthosis.