  In the past decades, a variety of haptic devices have been developed to
facilitate high-fidelity human-computer interaction (HCI) in virtual reality
(VR). In particular, passive haptic feedback can create a compelling sensation
based on real objects spatially overlapping with their virtual counterparts.
However, these approaches require pre-deployment efforts, hindering their
democratizing use in practice. We propose the Tracking Calibrated Robot (TCR),
a novel and general haptic approach to free developers from deployment efforts,
which can be potentially deployed in any scenario. Specifically, we augment the
VR with a collaborative robot that renders haptic contact in the real world
while the user touches a virtual object in the virtual world. The distance
between the user's finger and the robot end-effector is controlled over time.
The distance starts to smoothly reduce to zero when the user intends to touch
the virtual object. A mock user study tested users' perception of three virtual
objects, and the result shows that TCR is effective in terms of conveying
discriminative shape information.
