Quantitative Analysis of Vibrotactile Threshold and the Effect of Vibration Frequency Difference on Tactile Perception

In this paper, the effect of vibration frequency using a developed tactile display is described. In the first experiment, the skin perception threshold of vibrotactile stimuli at the finger tip is measured. From the experiment, the fingertip (right index finger) vibrotactile threshold is measured when the subjects start to feel the stimulus. The frequency is varied from 6.31Hz to 398.1Hz at a regular dB interval via a small contact area (0.196 mm², 0.785 mm² , and 3.142 mm²). The results show a U-shaped curve and the threshold is reciprocally related to the contact area. A second experiment is performed to examine whether a shape display on the fingertip area is possible by changing the vibration frequency without any change in amplitude when passive touch is applied at a tactile display mouse. The subjects were able to discern six different small scale shapes established via different vibration frequencies. From the result of the experiments, we can conclude that vibration frequency can be effectively employed to sense shapes with different heights, even when a stimulus having a fixed amplitude is applied