Design and Development of Prosthetic Arm for Above-Elbow Amputees

Abstract

People’s working capability is badly affected when they suffer with an amputated arm. Artificial replacements with prosthetic devices to get a satisfactory level of performance for essential functions with the currently available prosthetic technology are very difficult. Myoelectric arm prostheses are becoming popular because they are operated by natural operations of intact muscles. The objective of this work is to explore the various methodologies and algorithms used for surface electromyogram signal classification for the purpose of implementing the same in the developed prosthetic hand. In the present work, surface electromyogram (SEMG) acquisition system was designed keeping the economics and application in mind. After acquiring the signal, important aspect is to extract the features which are representative of surface electromyogram pattern for different arm functions. The study of different parameters in relation to signal variations with force level was carried out and it was found that both amplitude-related parameters and selected statistical parameters give good indication of force level. Further, the electrode placement points were compared with other locations on arm for best surface electromyogram acquisition. Interpretation of surface electromyogram signals using advanced techniques is a very important requirement in biomedical engineering. Recent advances in technologies of signal processing and mathematical models have made it possible to achieve this objective. Further electromyogram has encouraged human computer interactions for developing myoelectric signal based prosthetic devices. In the present research work, the main emphasis is on the study of surface electromyogram (SEMG) signals at multiple muscles points with different postures or movements for designing prosthetic device having usable degrees of freedoms (dof). Further, development and testing of the designed prosthetic arm on different amputees has been carried out. The objectives of this research include: 1) To develop electrode system for acquiring SEMG data from above-elbow amputees. 2) To simulate and analyze stored SEMG for different postures from three classes of above-elbow amputees. 3) To compare the actual SEMG with simulated model and verify the results with the help of soft computing techniques. 4) To design and develop electronic circuitry / mechanical structure for development of prototype model of 4 Dof prosthetic arm.