Optimal Design of Electrical Stimulation Electrode for Electrotactile Feedback of Prosthetic Hand

Electrotactile feedback plays an important role in the prosthetic hand system, whereas electrotactile method has the problems such as interference with electromyography (EMG) signals and low spatial resolution. This paper proposes a method to optimize the design of electrotactile electrode array to address above problems. According to the theory of nerve excitation and the electric field model on biological tissues, we proposed two optimizing targets for design: Noise Factor and Focusing Degree. Based on theoretical derivation of the relationship between electrode parameters and optimizing indices, we find that concentric circle electrode (CCE) with biphasic stimulation is superior over single circle electrode (SCE) on both indices. Use finite element analysis, we construct a more accurate electric field model to analysis. The result of FE analysis shows that CCE still had superiority over SCE when choosing optimized electrode parameters. Furthermore, we find out that when designing electrode array, the CCE have a huge advantages against SCE for its capacity of resisting disturbance so that we can design an electrode array with high density.