Upper Body Leaning can affect Forward Self-Motion Perception in Virtual Environments

Abstract

The study of locomotion in virtual environments is a diverse and rewarding research area. Yet, creating effective and intuitive locomotion techniques is challenging, especially when users cannot move around freely. While using handheld input devices for navigation may often be good enough, it does not match our natural experience of self-motion in the real world. Frequently, there are strong arguments for supporting body-centered selfmotion cues as they may improve orientation and spatial judgments, and reduce motion sickness. Yet, how these cues can be introduced without having to allow for physical user motion is not well understood. Actuated solutions such as motion platforms can be an option, but they are expensive and difficult to maintain. Alternatively, within this article we focus on the effect of upperbody tilt while users are seated, as previous work has indicated positive effects on self-motion perception. We report on two studies that investigated the effects of static and dynamic upper body leaning on perceived distances traveled and self-motion perception (vection). Static leaning (i.e., keeping a constant forward torso inclination) had a positive effect on self-motion, while dynamic torso leaning showed mixed results. We discuss these results and identify further steps necessary to design improved embodied locomotion control techniques that do not require actuated motion platforms.

Comparing leaning-based motion cueing interfaces for virtual reality locomotion

“…Given this limitation, participants still voiced they liked the motion cueing interfaces better than the Joystick because Interface they were fun, engaging, more realistic, and had the natural feeling of moving. This preference for a more embodied interface is consistent with related interfaces, such as the ChairIO [5], Gyroxus gaming chair [11], or leaning interfaces like the Joyman [3], Wii balance board-based standing leaning interfaces [4], [6], [37], [50] or interfaces where users merely lean their upper body while seated on a stable chair [38]. In order to increase familiarity, we recommend a sufficiently long training phase for unfamiliar motion cueing interfaces before any systematic experiments or testing.…”

“…Recent developments in 3D navigation interfaces have begun to take advantage of the power of body-centric physical cues [3]- [5], [11], [37], [38]. Beckhaus and colleagues [5] designed a stool based interface, called ChairIO, a chair-based computer interface that supports 3D motion -both directional and rotational.…”

“…Kruijff and colleagues [38] used a high resolution inclination sensor to measure user's leaning angle of their upper torso while seated and found that static leaning, i.e., keeping a constant forward torso inclination, increased the feeling of self-motion velocity but not vection per se. Dynamic leaning while seated using a "human joystick" metaphor, however, enhanced forward linear vection as well as user's involvement, engagement, and enjoyment compared to a joystick control.…”

“…According to the qualitative responses, the backrest of the office chair seemed to be an important contributor to the comfort level of the interfaces; both NaviChair and MuvMan interfaces lack a functional backrest, forcing participants to be more engaged with actively controlling their movement and posture. Studies that have looked at upper-body leaning have found that this engagement can be helpful in facilitating self-motion perception [36], [38]. Future studies will look into the effects of leaning.…”

Literature review of locomotion techniques in virtual reality

“…balance to the joystick and Walking-in-Place locomotion technique in a navigation task in a virtual environment(Harris et al, 2014) -Joystick Focusing on the effects of static and dynamic upper body leaning combined to the joystick on perceived distances travelled and self-motion perception(Kruijff et al, 2015) -Leaning body + Joystick Proposing and evaluating the usability of two locomotion techniques, both based on a combination of visual controls and hand gestures using low-cost sensors (Caggianese et al, 2015) -Combined tracking of the user's head and hand Comparison of joystick and four new locomotion techniques in a target finding task in an information rich virtual environment (Kitson et al, 2017a) a chair with leaning capabilities) Study the impact of the NaviChair, a new motion cueing locomotion technique on spatial updating compared to a traditional non-embodied interface (the joystick) (Kitson et al, 2015) a new high fidelity locomotion technique: Human Joystick and comparing it to joystick (McMahan et al, 2012) effectiveness of a new locomotion technique based on the motion capture of different parts of the user's body (Guy et al, 2015) -LazyNav Proposing a new locomotion method based on pressure cushion to explore virtual environment in a seated position (Ohshima et al, 2016) -Intuitive Striding UnitImplementing and comparing eight locomotion techniques in an immersive virtual reality test environment(Bozgeyikli et al, 2016a) …”