Prosthetic Arm Control using Microcontroller

Abstract

A prosthetic limb is an artificial device extension that replaces a missing body part. A prosthetic arm is a fake arm for those who amputated their arm. In addition to the standard artificial limb for every-day use, many amputees have special limbs and devices to aid in the participation of sports and recreational activities.

Prosthetic arm is a boon for those persons who have lost their arm due to some accident. The main requirement is that its function should be as near to the natural arm as possible. There are various designs of artificial arm that are available in the market, categorised as electrical, mechanical and Myo-electric arm. Mechanical prostheses use some motion of the body to provide the force necessary to control the prosthetic component. Electrical arms operate the hand by a motor which is driven by micro switches and relays. Myo-Electric arm is stimulated by muscle signal available from the amputee.

EMG signal detected by sensors or electrodes. The amplitude of the surface EMG signal (SEMG) varies from the µV to the few mV range. The rms value for the upper movement of the arm is more than the rms value for the down movement of arm. Similarly, rms value for the clockwise movement of the arm is more than the rms value for the anticlockwise movement of arm. Based on this a microcontroller was programmed to perform up/down and clockwise / anticlockwise movements in steps depending on the dc voltage level. The levels of the dc voltage corresponding to the EMG signal were taken.