In recent years, immersive VR ride experiences have been developed by combining electric wheelchairs, used as motion platforms (MPs), with virtual reality (VR) content through head-mounted displays (HMDs). This study focused on trajectory design particularly when small disk rotation was applied in a VR teacup ride, and examined the requirements through two experiments. Experiment 1 showed that adding translational motion improved consistency and self-motion compared with rotation-only or stationary conditions. Experiment 2 found that reversed trajectories at full speed increased discomfort, while halving translational speed mitigated these effects regardless of direction. These results suggest that carefully adjusted translational motion reduces physical displacement while preserving immersion, and that combining rotation with halved translational speed supports natural VR teacup experiences using electric wheelchairs as MPs.

Pseudo-attraction force, which is an illusory force sensation, is perceived when grasping an asymmetrically vibrating actuator with the fingertips. Unlike force feedback provided by grounded devices, pseudo-attraction force is more difficult to accurately perceive. Therefore, the application of pseudo-attraction force devices is limited depending on the accuracy of the user’s sensation. This study aims to improve the accuracy of pseudo-attraction force by using the contrast effect. In the experiment, using a two-dimensional pseudo-attraction force device, a pseudo-attraction force in the opposite direction was presented first as a contrast stimulus, followed by a 1000 ms presentation of the target pseudo-attraction force. The contrast stimuli, including no stimulus, were presented in random order with five different presentation times. There were four presentation directions, and the user answered the perceived direction. The results showed that the correct answer rate was high when contrast stimuli were presented for 500 ms. This study suggests the possibility of a contrast effect in which a short prior opposite direction stimulus enhances the directional perception of pseudo-attraction force.

Origami is popular not only as a traditional Japanese toy but also as an art form around the world. Origami artists have created many various works. In particular, the theory of how to design the base to fold out the flaps for shaping origami models has been widely discussed. Still, there are few systematic descriptions of the shaping process that lead to completion after designing the base. Therefore, in this study, we propose a “component design method.” This method enables designing the crease pattern by considering the shaping folds as a “component.” We also developed a web application, “Origami Face Maker,” with which users can design human faces with origami. In this application, the final crease pattern and the folded figure of human faces with different expressions are generated when users select preset components. This paper details the proposed component design method and analyzes user feedback from a questionnaire survey.

In this study, we propose an interaction method that links sound texture representation and sound image localization using granular synthesis in order to realize spatial acoustic feedback in response to body movements. By using a single sound file containing multiple environmental sounds arranged in chronological order and controlling the playback position according to hand position information, we have realized an experience in which the user can explore sound textures as if moving in a virtual space. The proposed system was implemented in two different exhibition conditions, a 15-channel loudspeaker environment and a 4-channel quadraphonic environment, and positive responses were confirmed in terms of the synchronization of sound texture and motion, as well as the spatial extent, through the comments obtained from the users. Even with a configuration using a small number of loudspeakers, the sound image tracking and texture changes in response to hand movements were perceived, suggesting the flexibility and versatility of this method. In addition, the playback position control corresponding to the vertical direction was effective in designing interactions that promote spatial cognition. This study presents new potential applications of spatial acoustics based on the connection between body movements and sound, and suggests future developments in multisensory interaction design in VR/AR environments.

In this paper, we report “MeiMeiRoRo,” an interactive artwork featuring a nested structure. “MeiMeiRoRo” presents an experience where its nested structure arises two states of consciousness: “active” and “passive.” These two states coexist because the nested structure establishes an identity between the giant maze in which the user exists and the miniature maze the user holds. A user’s active operations on the miniature maze indirectly control the life-size avatar in the giant maze. Since the miniature avatar represents the user himself/herself in the giant maze, the user is controlled passively by his/her own active operations. We conducted an evaluation experiment on this experience that generates “active” and “passive” states of consciousness. We found that expression of being tilted in the giant maze raises passive consciousness.

Redirection techniques enable motion amplification by subtly altering visual motion cues. This study investigates the detection threshold of the bending gain applied to passive roll-direction curved motion. Participants were seated sideways in an electric wheelchair and ascended a ramp with a curvature of 0.42, while virtual curvature was manipulated. The results showed that the virtual curvature can be amplified up to 2.9 times without detection, suggesting the potential for enhancing VR entertainment experiences through roll-direction curvature manipulation.

Motion sickness can be exacerbated when a head-mounted display (HMD) is used in the rear seat and visual information from outside the vehicle is blocked. This preliminary study explores whether supplementing the blocked visual information with car frontal camera images on a virtual display can reduce motion sickness. Participants highly susceptible to motion sickness read a book displayed on an HMD during repeated stop-and-go driving, both with and without car frontal camera background images. The results showed that the rate of increase in motion sickness severity was significantly reduced when car frontal camera background images were provided. These findings suggest that presenting car frontal camera background images on an HMD is a promising approach to enable comfortable reading, video viewing, and other activities in the rear seat.

While immersive virtual reality (VR) via head-mounted displays (HMDs) has advanced significantly, reproducing haptic experiences remains a key challenge. Emerging wireless HMDs with optical hand-tracking systems demand haptic feedback to the hands and fingers without holding handheld devices. This study presents a technique that combines tangential and vibration stimuli on the wrists to induce haptic sensations in the hands and fingers. Tangential forces directed toward the elbow increase skin tension, enhancing vibration propagation and creating an illusory sensation on the hands and fingers, which have higher vibrotactile sensitivity than the wrist. We developed an experimental system that controls tangential force, as well as the direction, amplitude, and frequency of vibration, to investigate their effects on the perceived location of vibrotactile stimuli. Experimental results show that applying tangential force significantly shifts the perceived vibration toward the fingers, particularly with normal actuation at higher frequencies. These findings inform the design of bracelet-type devices that deliver haptic sensations to the hands and fingers for the VR setup.

In VR, an abrupt transition to a virtual space can impair immersion, and methods such as orbs and portals have been studied in HMDs. In projective VR, users are aware of the real space before the experience, and this negative effect is thought to be even greater, but this has hardly been discussed. In this paper, we propose a projection mapping method that connects spaces via a door with an entity that the user can touch and operate. We have realized projection mapping to the area visible through the door frame, and clarified the requirements for the door frame. Evaluation experiments showed that the proposed method improves the immersive and entertaining experience.