The design and evaluation of a multi-sensory vibrotactile feedback system for a myoelectric prosthetic hand

Abstract

Upper-limb amputees have reported that one of their main dissatisfactions with current commercialised prosthetic arms is a lack of sensory feedback. The current study investigates the feasibility of providing feedback of grip force, slippage, and finger position through vibrotactile stimulators to the prosthetic users. Tests are performed to determine subject’s spatial sensitivity as well as their abilities to differentiate discrete vibration intensity levels. We find that human subjects can correctly identify discrete sensory levels (with 90% accuracy) from 62 Hz to 250 Hz for tactors placed at least 3 cm apart. The accuracy of the EMG classifier system would decrease if all three tactors are activated. Even though a multivariable vibrotactile feedback system may not be feasible initially due to information overload, the user performance may improve with training. Multi-tactor system can be implemented with a slight decrease in electromyographic signal classification for the control of a neuroprosthetic hand.