Feedback system based on current measurements to improve a hand prosthesis

Abstract

An improving to control a hand prosthesis prototype is presented on this paper, it is a feedback system to measure and limit currents for five actuators. Three different actuators were used: servomotor, stepper motors & gear motors. The hand performs two different movements: flexo-extension & abduction-adduction; is controlled via embedded systems using Arduino® platform, each finger has a defined trajectory, movements are free and the system doesn't take into account parameters such as: position, speed or torque. The control signals were from an EMG acquiring system based on four differential channels [1]. The acquire system process the signals to give movement commands to the control system of the hand. Feedback system is an addition to the hand control, previously reported by the same authors [2], it is divided in two: analog and digital. Analog is based on operational amplifiers to measure flow currents from each kind of actuator; Digital part is programmed over Arduino® platform to interpret the output from the analog part. Provides to the hand autonomy and free will to take advantage decisions about the movements for each finger. Leaving only to the hand to take the decision, excluding the prosthetic user in that moment.