T-Touch: a Soft Thermal-haptic Multimodal Fingertip Wearable Device for Immersive Virtual Reality

Abstract

Virtual reality (VR) technology has enormous applications in education, entertainment, and healthcare. Haptic feedback can significantly enhance the immersive experience in VR. However, most commercial hand/fingertip wearable VR haptic devices rely on bulky rigid structures, which are limited in the offered stimuli and cause fatigue. This study introduces a novel soft wearable fingertip device, T-Touch, that provides both thermal and multi-frequency haptic feedback for more realistic VR experiences. A flexible electrohydraulic actuator (EHA) is adopted for multi-frequency mechanical stimuli, and a flexible thermoelectric array (Flex-TEA) is utilized for distinct thermal stimuli. The EHA and Flex-TEA can be independently controlled to activate simultaneously or independently, thereby rendering ON/OFF contact stimuli, vibrations, controlled temperature stimuli, or any combination of the three modalities. Our T-Touch device features a compact form factor of 35 mm × 25 mm × 22 mm and weighs only ∼8 g. It can generate mechanical stimuli with the maximum stroke of ∼1 mm, a force of 0.47 N, at a bandwidth >10 Hz, and can render precise thermal stimuli in the range of 20 to 40 °C. The main performance of the EHA and Flex-TEA modules is characterized in extensive experiments and the effects of the key design and actuation parameters are investigated to optimise performance. Preliminary user tests verify the efficacy of our T-Touch design in immersive VR applications.