Study and Analysis of SEMG Signal for Enhancement of Above Shoulder Myoelectric Arm Functionality

Abstract

Upper limb amputation is a traumatic event that can seriously affect the person s capacity to perform regular tasks and can lead individuals to lose their confidence and autonomy. Prosthetic devices can give relief by acting as substitute the function of missing limb which can help to improve the quality of life of the amputees. In recent years, myoelectric devices have received extensive attraction to provide enhanced degree of freedom over traditional devices. Myoelectric prosthesis is controlled via the acquisition and processing of electromyogram signal produced at the muscles fibre from the surface of body with an array of electrode placed on the residual limb. The acquired signal is a complex one being dependent on the physiological and anatomical property of muscles. The electrodes convert muscles-activity from the torso into information that can be processed by different techniques. The unwanted noise contributes from the electrolyte skin surface, while travelling through the muscles. To make the noisy signal useful, advancement in the detection and processing of the signal becomes a very important requirement in biomedical engineering. The signal has to undergo pre-processing stage consisting of amplification, filtering and adaptive peak detection etc. to reduce the noise level in the raw signal. The different signal processing techniques such as time domain techniques, wavelet coefficients and autoregressive coefficients have been applied to increase the information yield from the EMG signal. Different algorithms to identify the intended movements are available that rely on the feature extraction that provide the user with access to multiple degrees of freedom and have shown great promise in research literature. The identified information of movements is translated into control signal to drive the artificial limb and the force generated by the artificial limb can be varied by the user s muscles intensity.