SurfaceFlow: Large Area Haptic Display via Compliant Liquid Dielectric Actuators

Touch perception is mediated by the skin, a highly compliant, distributed medium. In contrast, haptic displays frequently rely on rigid actuated elements. Here, we introduce a new haptic display based on compliant, liquid dielectric actuators. This display combines electrostatic attraction with hydraulic amplification provided by a liquid dielectric encapsulated in a compliant pouch. Voltage supplied to six pairs of opposed hydrogel electrodes generates dynamic variations in pressure on the encapsulated liquid. Mechanical amplification by the liquid enables the device to render tactile feedback with substantial displacements (> 2 mm) and forces (> 0.8 N) via a thin (< 3.5 mm) compliant surface with a large active area (75 cm²). The result is a soft, wearable tactile interface for providing dynamic haptic feedback to large areas of the skin. The intrinsic compliance of this interface lends a comfortable quality to the feedback it provides. We describe key considerations informing the design, including performance, reliability, and safety, and how these are addressed in our device. We describe a fabrication method that enable the device to be easily reproduced by others. We discuss a flexible multichannel system for dynamically controlling them. We also show how the display can produce unique haptic experiences, such as fluid-mediated haptic effects of motion across the skin.