On the Design of the 5-DoF Finger-wearable Cutaneous Haptic Device

Abstract

We propose a cube-type cutaneous haptic device that can be mounted on the user's fingertip and display 5-DoF (degree-of-freedom) touch/pressure to the fingerpad when manipulating objects in remote or simulated environments. For practical usability and high wearability/portability, we mainly aim to realize the haptic device having high-force multi-DoF functionality with compact and lightweight structure. To achieve the aim, multi-DoF miniature compliant mechanisms are designed and applied to the device as motion guides: a 3-DoF tip tilt mechanism and a planar 2-DoF XY mechanism for displaying touch/pressure and shearing force, respectively. To reduce the overall size of the device, the two complaint mechanisms are designed with a flat structure and they are stacked in series. And as the actuators suitable for the compact wearable devices, the SMA (shape memory alloy) actuators well known as solid-state smart actuators are considered due to its high energy density (force-to-weight ratio) characteristics. The proposed haptic device is fabricated as a polymeric functional prototype with 3 dimensional printer. And the working performances of the device such as output displacement, force, and frequency response characteristic are experimentally evaluated.