Encountered-Type 3D Haptic Shape Display by Simulating Finger-Object Contact Regions.

Encountered-type pin-array shape displays allow users to freely explore a simulated shape using bare fingers. However, current pin-array shape displays are limited to discontinuous shapes or 2.5D shapes. Here, we propose a novel shape display principle to render touch feedback between a virtual hand and objects in a virtual reality environment. The configuration of the shape display with 20 actuators consists of four finger-like units. The shape display renders the local contact regions between the shape and the user's finger. Users can sense the touch of the virtual objects by encountering the finger-type shape display. A fiber-reinforced origami soft actuator was designed to allow the finger-like unit to bend and laterally swing like a finger joint. The device's kinematic model and the shape planning algorithm for finger-object interaction were developed to map the virtual shape and user fingers to the finger-object contact regions and the actual actuation parameters. Six categories of 11 virtual shapes were rendered by the shape display. The results indicated that the proposed device can render 3D continuous edge and surface-type shapes. We envision that the shape display can render a wide range of shapes in combination with a mobile platform to reduce the complexity of haptic shape display in virtual worlds using a relatively small number of actuators.