Multi-mode soft haptic thimble for haptic augmented reality based application of texture overlaying

This paper presents a novel thimble-shape haptic display for multi-mode tactile feedback at fingertips. The device has two special characteristics. Multi-mode feedback, i.e., static pressure, high-frequency vibration, and impact force, can be generated via a single actuator mechanism of a pneumatic chamber controlled by high-speed valves. Additionally, the actuator's softness makes this device a “feel-through” tactile display where the user simultaneously feels responses from a real object and synthetic feedback. This makes the device a fit for haptic augmented reality-based display where real and virtual touch feedback is merged into single feedback that haptically “augments” the real world. A layered combination of flexible and non-flexible silicone membrane surrounds the air- cavity for desired efficiency, and systematic valve control algorithms are developed for rich haptic effects. The experiments confirmed that the system generated a static force up to 7 N, acceleration magnitude up to 1.4 G, and frequency up to 250 Hz. The device exhibits two realistic tactile signals, i.e., virtual textures and button clicks, based on real signals and a physical surface that are augmented with two haptic signals.The user studies revealed that the participants found the virtually overlaid textures and buttons to be perceptually similar to their real counterparts.