BIOELECTRIC CONTROL OF PROSTHESES
MASSACHUSETTS INST OF TECH CAMBRIDGE RESEARCH LAB OF ELECTRONICS
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Externally powered prostheses have been studied for many years, to provide more effective rehabilitation of amputees. To take advantage of the benefits offered by external power in prostheses, however, the mode of control of the prosthesis by the amputee must be improved. Conventional control methods require a high degree of mental concentration by the amputee on his prosthesis, because of at least two important factors i the mode of control of a prosthesis motion is different from control of the corresponding normal action ii there is no feedback of sensation from the prosthesis to the patient except through the visual sense. The present system utilizes surface electromyographic emg signals from the biceps and triceps of an amputees arm to provide graded control of an elbow prosthesis. Included as an intermediate step is the control of a simulated forearm in a digital computer, in real time. At present, the signal processing consists of full-wave rectification and lowpass filtering of the emg signals from biceps and triceps muscles mechanical elbow prothesis can now be voluntarily controlled through the subjects emg signals. The performance of the system and indications for future work are outlined. Foremost is the need for feedback to the patient of position information from the prosthesis, outside of the visual sense. A possible method for accomplishing this in an inherently normal manner is suggested. The use of nerve signals as the control signal for a prosthesis offers potential advantages over the use of the emg signal the practical problems in observing nerve signals, combined with lack of information on how to interpret them, makes this approach infeasible now.
- Medicine and Medical Research
- Biomedical Instrumentation and Bioengineering