System Design And Machanism Study On Cutaneous Electrotactile Stimulation

Nowadays, haptics has been widely used in many fields such astelecontrol robots, surgical robots, prosthesis, entertainment interface andvirtual reality and so on, which improves the operability of actual orvirtual objects (robots, prosthesis etc.) for human. Electrotactilestimulation is a main technique to reproduce tactile sensation by changingthe frequency, duration, amplitude, direction and distribution ofconstant-current electrical pulses. In this work, a system for realization ofcutaneous electrotactile stimulation is designed, and mechanisms ofelectrotactile sensation are studied.Firstly, the stimulation system for cutaneous stimulation is developedbased on analysis of human skin impedance. Then a model of nerves underelectrical stimulation is built to serve for simulation study. The optimalparadigms for stimulating three mechanoreceptors (Meissner’s corpuscle,Merkel’s disc and Pancinian corpuscle) separately are found in atrial-and-error way, i.e. by changing the direction and amplitude ofelectrical pulses in arrays through simulation study. Furthermore,psychophysical experiments are carried out to make experimenters sensetwo kinds of feelings (vibration and pressure) using different stimulationpatterns, and the corresponding classification results are achievedaccording to the experimenters’ subjective judgment.At last, mechanism study on quantification of electrotactile feeling isperformed. It is known that the action potential signals generated frommechanoreceptors are transferred to brain in a one-to-one way through ahuge number of nerves, so it is very difficult to measure such a great deal of signals comprehensively at microscopic level. In a word, it is a bigchallenge to quantify the electrotactile feeling at present. Regarding thisissue, a novel method based on brain-computer interface (BCI) isproposed in this work. Event-related potentials (ERPs) and event relateddesynchronization/synchronization (ERD/ERS) extracted fromelectroencephalograph (EEG) are used as evaluation indexes. Statisticalanalysis is performed. The results show that ERPs and ERD/ERS candiscriminate different sensations due to different stimulation patterns. Thismethod opens a promising window for quantification of senses in future.