Compact Hip Force Sensor for Gait Assistant Exoskeleton System
Journal
sensors
Date
2018.02.13
Abstract
The paper proposes a compact force sensor system of a hip mounted exoskeleton for seniors with difficulties in walking due to muscle weakness. It senses and monitors the delivered force and power of the exoskeleton for motion controls and urgent safety actions. Two FSR (Force Sensitive Resistor) sensors have been used to measure assistance force during the walking of users. The sensor system measures the interaction force between exoskeleton and lower limb of the users directly, instead of a previous force sensing method which estimates hip assistance force from the current of the motor and lookup tables. And the sensor system have an advantage to generating torque of actuator for walking assistant based on direct measurement of hip assistance force. Thus, the gait assistance exoskeleton system can control the delivered power and torque to the users. The force sensing structure is designed to decouple force from hip motion and other directional force to the sensor for measuring only the force by the hip motion. The proposed prototype compact force sensor is confirmed that the hip assistance force can be measured with the sensor attached to the thigh frame through the experiment of real system.