The Effects of Vibrotactile Stimulation of the Upper Extremity on Sensation and Perception

Vibrotactile stimulation has applications in a variety of fields, including medicine, virtual reality, and human-computer interaction. Eccentric Rotating Mass (ERM) vibrating motors are widely used in wearable haptic devices for their small size, low cost, and low energy features. The effect of ERM motor vibrations on upper extremity sensation and perception have not been thoroughly studied previously, which is important to design better wearable haptic devices. We conducted experiments with vibrotactile stimulation on 15 healthy participants. Eight motors were placed on a consistent set of muscles on the upper extremity and one motor was placed on the index finger. We found a significant correlation between voltage and sensation intensity (r=0.39). However, we did not find a significant aggregate-level correlation on the perceived pleasantness of the simulation. The sensation intensity varied based on the location of the vibration on the upper extremity (with the lowest intensity on the triceps brachii and brachialis) and slightly decreased (5.9 {+/-} 2.9 %) when participants performed reaching movements. When a single motor was vibrating, the participants accuracy at identifying the motor without visual feedback increased as voltage increased, reaching up to 81.4 {+/-} 14.2 %. When we stimulated three muscles simultaneously, we found that most participants were able to identify only two out of three vibrating motors (41.7 {+/-} 32.3 %). Our findings can help tune stimulation parameters in human- machine interaction applications.