Comparison of electro-tactile and mechanical-tactile feedback in human glabrous skins

Traditional tactile feedback devices not only take more energy but also occupy more space. When these devices provide force feedback, devices may also be associated with resonance and reduce natural feeling and user experience. However, electro-tactile feedback is different from mechanical-tactile feedback, and it can solve the above problems. By using different stimulus waveforms, electro-tactile feedback can provide different tactile sensations. In this study, we use electrical stimulation to provide tactile feedback and create an electro-tactile feedback prototype device. Using Arduino to control the digit-control resistance in booster circuit, this prototype can output different voltages. We also establish an H-bridge circuit for controlling the flow of stimulation, and provide an anode, a cathode and a biphase electro-tactile feedback. In addition, this study also established a mechanical haptic prototype device consisting of a micro-speaker, with the input of human glabrous sensitive vibration frequencies and voltages to achieve different tactile sensations. This study also conducted a user test for electrical polarity and frequency resolution. Results showed that subjects can distinguish different polarities up to 80% of accuracy. It means that with different electrical polarity, subjects have different electro-tactile feedback. Except the frequency of 50Hz, subjects can distinguish different frequency more than 70% of accuracy. It means that with different electricalfrequencies, subjects have different electro-tactile feedback. This study also conducted electro-tactile and mechanical-tactile feedback rating test to test the subjects’s feelings for both feedback. By adjusting the input frequencies of the mechanical vibrations and voltage magnitudes, we found the parameters which mechanical tactile feedback is similar to the electro-tactile feedback. Designer can design the electro-tactile or mechanical-tactile feedback devices which provide different feelings through these parameters.