FDM 3D printers allow massive creativity in personal products, but their potential has been limited due to inability to manipulating material properties. Previous work had demonstrated that the desired roughness could be presented simply by controlling the spatial density of tiny pins on a printed surface. This article offers a means of providing the desired softness perception of a printed surface and the desired roughness to expand the haptic dimension over which a user can exert control. Specifically, we control the softness by manipulating the infill structures of a printed surface. However, it is known that a skin contact area affects softness perception. The roughness, which is controlled by pins' density, may also affect the perceived softness of a printed surface. Therefore, we investigate how the internal structures and the density of the pins affect softness perception. Through psychophysical experiments, we derive a computational model that estimates the perceived softness from the density of the pins and the infill density of a printed surface. c 2021 Society for Imaging Science and Technology.
Current virtual environments rely heavily on audio and visual feedback as a form of sensory feedback [1]. The degree of immersion can be increased by augmenting synthetic haptic feedback from the user interface. Most of the existing wearable haptic feedback systems use tactile stimulation by vibrating motors for haptic feedback which lack a compelling sense of immersion with force feedback[2][3]. e.g.in the case of pressing a button. This research addresses this issue with hardware architecture for kinesthetic force feedback. This research focuses on the design of a wearable soft robotic haptic feedback glove for force feedback in virtual environments. The glove provides a force feedback to the fingers while clicking a button in virtual environments. The glove design includes a soft exoskeleton actuated by Mckibben muscles which are controlled using a custom fluidic control board [4]. The user's fingers are tracked using the infrared cameras. This tracking system provides the information for the position of the user's fingers. Based on this information, the soft glove is actuated to provide a haptic feedback. The Soft exoskeleton and actuation make the glove compliant, compact and unintimidating as compared to force feedback glove with rigid kinematic linkages. The glove design is inexpensive, mass-manufacturable and compatible to 90% of the U. S. population. The user could test the glove by playing the piano in virtual reality environment. The presence of audio, visual and haptic feedback makes the virtual reality environment highly immersive. The informal pilot study indicates that haptic glove improves the immersive experience of the virtual reality environments. Users in informal pilot study described the experience as "like nothing seen before", "mesmerizing" and "amazing".