Move or Push? Studying Pseudo-Haptic Perceptions Obtained With Motion or Force Input

Pseudo-haptics techniques are interesting alternatives for inducing haptic perceptions, achieved by manipulating haptic perception through the appropriate alteration of primarily visual feedback in response to body movements. However, the use of pseudo-haptics techniques with a motion-input system can sometimes be limited. This paper investigates a novel approach for extending the potential of pseudo-haptics techniques in virtual reality (VR), focusing on pseudoweight perception as the target case. The proposed approach utilizes a reaction force from force-input as a substitution of haptic cue for the pseudo-haptic perception. The paper introduced a manipulation method in which the vertical acceleration of the virtual hand is controlled by the extent of push-in of a force sensor. Such a force-input manipulation of a virtual body cannot only present pseudo-haptics with smaller physical spaces and be used by various users including physically handicapped people, but can present the reaction force proportional to the user's input to the user. We hypothesized that such a haptic force cue would contribute to the pseudo-haptic, here, the pseudoweight perception. Therefore, the paper endeavors to investigate the force-input pseudo-haptic perception in comparison with the motion-input pseudo-haptics. The paper compared force-input and motion-input manipulation in a point of achievable range and resolution of pseudo-weight. The experimental results suggest that forceinput manipulation successfully extends the range of perceptible pseudo-weight by 80% in comparison to the motion-input manipulation. On the other hand, it is revealed that motion-input manipulation has 1 step larger number of distinguishable weight levels and is easier to operate.