TG2 : simulating haptic impact in immersive systems

Abstract

In this work we explore the haptic pendulum, a device originally developed in our VIS (Visualization, Interaction and Simulation) Lab to generate sensation of holding different weights in VR. The goal of the present project was to redesign and assess the device as a means to provide force and mobility to VR haptics. It is known in the research community that force feedback device designs prioritize a grounded construction, where the ground offers an inertial support to be able to produce force. This is not ideal for VR where free motion is desirable. While previous works offer some alternatives by attaching devices to body parts or using propellers, none of them proposed a 2 degrees-of-freedom mass displacement handheld controller. Our pendulum device consists of a mass that is driven by two servo motors on the surface of an imaginary hemisphere on top of the user’s hand. The motors and mass construction is fixed upon a standard VR controller (HTC Vive) that is held by the user that interacts in the virtual environment. The pendulum was rewired from the original weight percep tion configuration to convey directional impulses instead of weights. While weights are stable forces towards the floor, directional impulses are instantaneous forces in controlled directions. We then designed and conducted an experiment with users to assess how the impulse stimuli are perceived. We tested three dimensions for the system capabilities. The ability to convey different directions, different intensities and sequences of impulses. Results show that directions can be identified, although not precisely, that the intensities tested are mostly well identified, and that sequences of impulses are correctly perceived even with sub-second time interval between impulses.