Perceiving Weight in Augmented Reality using a Wearable Device with Minimal Haptic Feedback

While at first glance one might assume haptic devices for Virtual Reality (VR) would directly translate to use in Augmented Reality (AR), key differences in how users interact with these environments create distinct design constraints. AR allows users to see their surroundings and interact with both physical and virtual elements, requiring virtual objects to convey the same sense of weight as their physical counterparts. However, force feedback solutions developed for the more mature field of VR are not compatible with this blended environment as they occlude the user's hand and prevent interaction with physical objects. We present a novel exoskeleton, Wriality, that utilizes a minimal feedback design to render weight-related forces while maintaining natural engagement with an AR environment, providing a more immersive experience than current state-of-the-art solutions. We present the design and characterization of Wriality and then validate its effectiveness with a human subject experiment. We show that, with force compensation, kinesthetic feedback alone can allow a virtual object to be perceived as equal in weight to its real twin. We show that this force compensation varies with both grip method and with the weight of an object. We then present the subjective feedback on user experience, specifically comfort level, and the effects of the device on realism and immersiveness in AR. Our findings show that the minimal force feedback approach exemplified in Wriality is still effective in providing high levels of immersion by incorporating a force compensation scheme based on intended grip and the object's weight. The results of our user feedback also inform design considerations for future haptic devices targeting AR.