Realistic Haptic Rendering Based on Piezoelectric Multimorph Actuators for Human-Interactive Tactile Communication System

In an immersive virtual interaction, realistic sensory devices allow users to provide richer experiences such as vision, hearing, touch, smell, and even taste. Recently, several haptic devices including tactile gloves [1], full-body haptic suits [2], and joysticks [3] are interesting and significant attention for human perception. However, most commercial haptic solutions are insufficient to fully immerse users in virtual environments due to the haptic feedback which is not similar to the real-like feeling. To enable sophisticated tangible interactions, it is essential to reproduce the realistic haptic signals using rendering technology in haptic interfaces between the sensor and actuator. In this study, we proposed a human-interactive tactile communication system using a piezoelectric multimorph actuator capable of both sensing and actuating functions simultaneously. The piezoelectric actuator was designed with multimorph structure with improved displacement (&gt; 800 um) than the traditional PZT ceramic. Our actuator also exhibited uniform vibrations with input signals of frequencies ranging from 1Hz to 1kHz. which is within the perceivable frequency ranges of the human Pacinian corpuscle. To demonstrate the proposed system, 3 different textures are prepared to represent the smooth and rough feeling of the surface. While dragging the textures with the device attached to the fingertips, the signals obtained from the self-sensing actuator are classified by principal component analysis (PCA) with high accuracy of 96 %. Subsequently, rendered signals are generated by extracting key features such as the envelope of the waveform, main frequency, and amplitude based on the PCA. Finally, the actuator reproduces the rendered haptic feedback in real-time. The tactile sensing/actuating communication system is utilized in fields of artificial skin for robotics, and remote tactile communication in virtual reality.<br/><br/><b>References</b><br/><i>[1] J. Perret and E. V. Poorten, "Touching virtual reality: A review of haptic gloves", Proc. Int. Conf. New Actuat., pp. 270-274, Jun. (2018).<br/>[2] Mahmud, M. Rasel, et al. "Standing Balance Improvement Using Vibrotactile Feedback in Virtual Reality." arXiv preprint arXiv:2208.09082 (2022).<br/>[3] Choi, Jiwook, et al. "Impedance matching control between a human arm and a haptic joystick for long-term." Robotica 40.6 (2022): 1880-1893.</i><br/><br/><b>Acknowledgement</b><br/>This work was supported by Institute for information & Communications Technology Promotion (IITP) grant funded by the Korea government (MSIT, Grant No. 2020-0-00003, Development of high piezoelectric coefficient composite and ultra-low power multilayered piezoelectric sensor/actuator multi-functional module) and the Technology Innovation Program (RS-2022-00154781), funded By the Ministry of Trade, Industry & Energy (MOTIE, Korea).