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| A Control System for the Myoelectric Prosthetic Hand with Adjustable Grip Speed |
| Institute of Biomechanics and Rehabilitation Engineering, University of Shanghai for Science and Technology, Shanghai 200093，China |
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Abstract In this study,an intelligent electromyography prosthetic hand with adjustable grip speed was developed. In this system, the surface electromyography signals (sEMG) acquierd by surface electrodes was preliminarily amplified about 150 times and processed using frequency domain analysis method. Through threshold and the equivalent calculation, the control signal was input into the driving circuit of DC micro motor for the prosthetic hand. 10 volunteers attended the gripping experiments and each experiment was repeated five times. Under the condition that the amplitudes of sEMG were 500, 1 000and 1 500 mV, the mean and standard deviation of the signals, including output voltage, output current and grip strength, were recorded. The relations among output voltage, output current, grip strength and sEMG ampltude were obtained by fitting analysis. The results indicated that the prosthetic hand speed positively corelated with the output voltage. with load but not overload， grip strength increased with the increasing output current. The results proved the stability of the developed system. And the grasping speed of the system can be adjusted as well. The system with adjustable grip speed improves the flexibility of the prosthet hand.
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