Design Of An Upper-Limb Prosthesis Towards Amputees With High-Level Amputation Based On TMR

Research on Electromyography(EMG)controlled prosthesis has developed for many years and there have been many commercial prostheses available for individuals.Although the corresponding nerve still exist in the brachial plexus nerves,the upper arm amputee can't control those prostheses intuitively as they lose the surface EMG(sEMG)signal generated from the muscle to control the wrist and hand.With targeted muscle reinnervation(TMR)surgery,muscle reinnervated with targeted neural inputs can amplify the neural signal into EMG signals which can then be used to control the prosthesis.To rebuild the motor function of the upper arm amputee,this paper designed a sEMG-controlled upper-arm prosthesis and the interactive interface was also developed for upper-arm amputees who had received TMR.The hardware system of the prosthesis consists of its mechanical structure and electrical hardware.The mechanical structure includes the hand,wrist,elbow,socket and shell.And the Electrical hardware has two subsystems: motion control system and tactile feedback system.The motion control system includes the EMG sensors,motor driver,mechanical hand controller and main controller.While the tactile feedback system includes the tactile stimulator,tactile sensor and main controller.Both of the two subsystems were supervised by the main controller.Despite several months' rehabilitation training after surgery,the cocontraction of different targeted muscles still existed.To deal with this problem,a linear discriminant analysis(LDA)classifier based on Bayesian decision was utilized.To further improve the function of prosthesis,this paper applied pattern recognition techniques in conjunction with amplitude based control strategy to classify the surface EMG signals recorded over the reinnervated muscles.The off-line analysis of data sets indicated that the hybrid control strategy eliminated the adverse effect of transient signals in a large extent.The Functional test demonstrated that the prosthesis could help the amputee complete some basic tasks in daily life.