Presentation of surface height profiles based on frequency modulation at constant amplitude using vibrotactile elements

This study attempted to observe what effects the frequency modulation of vibration elements produce in representing a tactile shape. Tactile shapes were modulated based on frequency difference at constant amplitude through a tactile feedback array of 30 (5 × 6) pins, which stimulated the finger pad. Experiment I showed that participants feel height changes when modulating frequency. In Experiment II, the participants were asked to discriminate three basic tactile shape patterns, which were generated with different frequencies at constant amplitude. Experiment II proved that spatial height information can be represented by modulating temporal information. In Experiment III, the frequency modulation method was applied to the tactile mouse system. Dynamic frequency modulation at passive touch can be used to transmit tactile height pattern information to the user of the mouse pointer for more practical application. The results showed that the participants were able to discern eight predefined shapes with an accuracy of 98.4% upon passive touch.