Elastowave: Localized Tactile Feedback in a Soft Haptic Interface via Focused Elastic Waves

It is challenging to engineer programmable tactile displays to match human haptic abilities. Such displays are often composed of elements whose stiffness contrasts greatly with the softness of many natural materials. Emerging soft material technologies hold promise for their ability to conform to many objects, including the human body. However, rendering localized feedback from soft haptic devices remains challenging. Here, we present the Elastowave, a soft tactile interface that provides localized tactile feedback via a soft, compliant surface. We achieve this by focusing elastic wave fields generated by a compact array of remotely-positioned actuators. Our method is based on new variations of time-reversal focusing techniques for elastodynamic waves. Our system can provide dynamic, single- or multi-point localized tactile feedback with centimeter-scale resolution across a deformable interface with an area of 175 cm2 . The sizeable displacements of the focused tactile signals enable them to be easily felt, as our experiments show. This work could enable the design of a multitude of new soft tactile interfaces in areas such as creative computing, product design, and augmented reality.