Passive Haptic Feedback for More Realistic and Efficient Grasping Movements in Virtual Environments

Achieving natural interaction in virtual environments is essential to create realistic simulations in various fields, including healthcare and education. The ability to interact in Virtual Reality (VR) in a natural way, through a combination of visual and physical feedback can greatly enhance the experience and effectiveness of these simulations. Recent works have shown that the lack of haptic and tactile feedback produces significant differences in grasping actions performed in immersive VR, with respect to the same actions performed in the real world. The passive haptics approach, which relies on physical proxies to introduce tactile feedback in VR, has been explored to address this issue. This work focuses on a specific interaction task that involves both hand movements and grasping: pouring coffee into a cup and mimicking the action of drinking it. We take into account three different scenarios: a traditional VR environment where virtual objects don't have any real counterparts; an MR environment that uses an ecological object substitution technique where the user can interact with real objects that are tracked in real-time and see a virtual counterpart; and the corresponding real scenario. We compute the Minimum Jerk Cost and the Dynamic Time Warping distance between trajectories as metrics to compare movements in the different modalities in terms of their smoothness and trajectory shape, respectively. Our results show that movements in MR environments are smoother and produce more similar trajectories to real-world movements compared to classical VR environments. This indicates that MR with passive haptic feedback could produce more realistic and efficient human movements in virtual environments.