Soft bidirectional haptic I/O module based on bi-convex patterned PVC gel

Abstract

In this paper, we propose a bidirectional soft haptic I/O module that not only senses the haptic force but also generates a mechanical vibrotactile sensation. Under external pressure, the distance between the moving plate and lower electrode layer decreases, and the bi-convex patterned poly vinyl chloride (bpPVC) gel gets compressed. These two motions make the capacitance of the proposed module change. Moreover, the application of external electric field (EF) creates an electrostatic force between the upper and lower electrode layers and generates the electric-field-induced deformation of the bpPVC gel simultaneously. As soon as the external EF disappears, the proposed module regains its original shape through the elastic restoring forces of the bpPVC gel and planar springs. Therefore, the applied AC voltage makes the proposed module vibrate. The dielectric and mechanical properties of the bpPVC gel are measured to investigate the optimal weight ratio of the PVC and plasticizers. Experiments are conducted to measure the haptic sensing and actuating performance of the proposed method. The capacitance of the proposed haptic I/O module increases from 17.4 pF to 54.8 pF when the external pressure varied from 0 kPa to 100 kPa. On the other hand, the haptic output of the proposed I/O module is observed as 0.81g (g = 9.8 m s−2) at 100 Hz. The results clearly indicate that the proposed haptic I/O module not only senses the static and dynamic pressure but also controls the amplitude of vibrotactile sensation. Owing to its mechanically soft structure, we expect that the proposed haptic I/O module has the potential to be applied or attached to various flexible/soft devices or the human body.

Dynamic braille display based on surface-structured PVC gel

“…As the specifications of the existing wire mesh are incomplete and the manufacturing process in laboratory is complex, Helps et al [44,45] presented a different design for PVC gel actuators, using copper foil anode instead of stainless mesh anode, in which the creeping space previously provided by the mesh is instead embodied on the PVC gel itself. K. H. Park et al [46][47][48][49] prepared a vibrotactile actuator based on wave-shaped PVC gel by casting method and applied it to wearable devices. Motohashi et al [50] prepared a kind of PVC gel by pressing the gel using heated iron plates and applied it to a peristaltic micropump.…”