Development of a robust microcontroller based output feedback control for assistive limb

This work is an effort towards developing a closed loop driving system to actuate the assistive device using DC series motors which will support the user by locking the knee during stance phase and un-locking during swing phase of human locomotion. The design of the driving circuit is based on data´s obtained from video analysis of human locomotion and PIC18F is the Master controller which helps in driving the DC series motors thereby mimicking human gait cycle. The PIC16F acts as the Client Module with which the user can enter the desired angle for actuating the driving circuit. The control and feedback of the motors is done using an optical encoder which gives out pulses according to the angle of rotation of the motors to the client module. The Client module compares the input and the feedback pulses and modifies the error by generating suitable output pulses. The speed of the motors is controlled by Pulse Width Modulation (PWM) technique and is achieved with the help of 555 timer and potentiometer.