Closed-loop control of motor-based leg orthosis for leg exercise

This paper presents the development of a lower-limb orthosis to help individuals with Spinal Cord Injuries (SCI). The idea is to develop a closed-loop control motor-based leg orthosis which can be used for leg exercise. Motor-based orthosis will be attached to the subject's leg while they are required to sit on the chair during the exercise. The closed-loop control orthosis is developed using several major equipment. There is microcontroller PIC 16F877A, DC motor, gear mechanism system and potentiometer. Initially, the orthosis can be set from 0 degree to 90 degrees and the input data is stored inside the microcontroller before it sends a signal to the actuator. After receiving a signal, the actuator will physically made a movement until the sensor reads the correct measurement of angle value. In this experiment, a Proportional Integral Derivative (PID) control will be implemented in the system. Finally, the hardware is tested on 7 healthy subjects with different body mass and height.