Locomotion Method Research Articles

Natural- and redirected walking in virtual reality: Spatial performance and user experience

AbstractImmersive virtual reality offers a range of unique possibilities. One of these is the realistic exploration of virtual worlds using natural walking. This however becomes difficult when the size of the virtual world exceeds that of the available physical space. Redirected walking in virtual reality presents a novel solution to this problem by typically making its users think to be walking in a straight line while they are in fact walking in a curve, thus allowing them to physically walk long distances in confined physical spaces. Yet, few studies have examined the effects of redirected walking on variables such as spatial memory, navigation and user experience as compared to other immersive and non-immersive locomotion methods. In a maze task we examined 1) redirected- and 2) natural walking in immersive virtual reality conditions, and 3) artificial locomotion on a non-immersive desktop monitor. Walked path lengths became shorter and distance estimates, object location memory and user experience improved using natural walking compared to a monitor condition. However, redirected walking yielded similar performance to natural walking while requiring less physical space, opening up possibilities for more pervasive use of real locomotion in virtual environments.

How to Help Older Adults Navigate Through VR? Effects in Outdoor–Indoor Transition Environments

In more complex outdoor–indoor transition scenarios, people were more prone to getting lost due to difficulties in effectively integrating proprioceptive cues and external navigation cues. Previous research had mostly focused on spatial perception driven by head or limb movements, with less discussion on locomotion methods that involved significant visual discrepancies. The challenge in designing navigation systems lies in balancing the enhancement of wayfinding performance with the potential negative impact on spatial cognition. We believe that navigation legibility might be a key optimization approach. Additionally, the differences in performance between different age groups were also worth investigating. Therefore, this study aimed to explore how locomotion methods and navigation legibility affected wayfinding performance, navigation interaction, navigation regression, and spatial cognition in younger and older adults during outdoor–indoor transition scenarios. Twenty-four younger (aged 19–27) and 24 older adults (aged 60–83) underwent VR wayfinding tasks. Participants initially followed virtual phone navigation from outdoor starting points to indoor endpoints, then drew cognitive route maps. Five main findings emerged: Continuous teleportation positively affected navigation performance and global representation of routes. Improving navigation legibility boosted navigation interaction, navigation regression, and global representation of routes. Older adults engaged more in navigation interaction but less in navigation regression, exhibiting poorer performance and route representation. Location-specific differences were observed in locomotion, legibility, and age effects. Furthermore, most older adults and over half of younger adults displayed a deflection effect based on outdoor–indoor (OI) space in route representation. These findings indicated that continuous teleportation and enhanced navigation legibility could improve user experience and spatial cognition, highlighting the importance of considering user age and the characteristics of outdoor–indoor transition scenarios when optimizing navigation methods.

A data-driven control method for ground locomotion on sloped terrain of a hybrid aerial-ground robot

In this work, we present a data-driven solution for the attitude control of DoubleBee on slopes. DoubleBee is a novel hybrid aerial-ground robot with two rotors and two active wheels. Inspired by the physcics modeling of the system, we add a channel-separated attention head to a deep ReLU neural network to predict disturbances from ground effects, motor torques and rotation axis shift. The proposed neural network is Lipschitz continuous, has fewer parameters and performs better for disturbance estimation than the baseline deep ReLU neural network. Then, we design a sliding mode controller using these predictions and establish its input-to-state stability and error bounds. Experiments show improvements of the proposed neural network in training speed and robustness over a baseline ReLU network, and a 40% reduction in tracking error compared to a baseline PID controller.

Design & Fabrication of Vertical Surface Cleaner

Abstract: The Wall Climbing Robot designed in this study to combines the innovative propulsion system of propellers with the traditional locomotion method of wheels to achieve versatile and efficient mobility on both vertical and horizontal surfaces. By integrating propellers and wheels, the robot can seamlessly transition between climbing walls and moving along flat surfaces. The hybrid design not only enhances the robot's mobility but also optimizes its energy efficiency, making it suitable for prolonged missions in various environments. This research explores the synergistic integration of propellers and wheels, showcasing the robot's adaptability in real- world applications such as surveillance, inspection, and maintenance tasks in both indoor and outdoor scenarios. The developed Wall Climbing Robot presents a significant advancement in robotic mobility, offering a promising solution for complex tasks in diverse settings

Performance and Navigation Behavior of using Teleportation in VR First-Person Shooter Games

Teleportation has been adopted as the preferred mode of navigation in many virtual reality (VR) experiences due to its ability to allow users to easily move beyond the limitations of the tracking space while minimizing the risk of inducing VR sickness. Teleportation instantly translates the user’s viewpoint to a user-selected destination and therefore eliminates any optical flow generation that could cause visual-vestibular conflict. Though teleportation is a discrete navigation method unique to the domain of VR, most VR experiences are modeled after 3D experiences found on desktop/console platforms that use continuous locomotion. How the use of teleportation affects the performance and navigation behavior of its users, especially in competitive first-person shooter environments is unknown, yet it could have a significant effect on gameplay design. We conducted a user study (n=21) that compares teleportation versus continuous locomotion using a VR first-person shooter game with other players being simulated using AI agents. We found significant differences in performance, navigation behavior, and how both locomotion methods are perceived by its users. Specifically, using teleportation, players traveled farther, but during combat were found to be more stationary and as a result got hit more frequently. These differences were profound and carry the potential to impact multiplayer games. We discuss possible strategies to balance gameplay.

RPG: Rotation Technique in VR Locomotion using Peripheral Gaze

Locomotion is an important task in many virtual reality (VR) applications. Locomotion requires two different directional settings for: (1) translation to a target, and (2) body rotation. Conventional locomotion methods mostly make use of the hand-held controller for such directional control. The controller-based directional setting may not be natural, as in real life, humans set directions with the gaze, often together with the head/body rotation. Note that the view direction is independently and naturally controlled by the head (or gaze) direction. In this paper, we propose to use the peripheral gaze for body rotation, seamlessly together with the foveal gaze for the view control, so that the two tasks practically do not interfere with one another. In the comparative study, the peripheral gaze showed similar task performance to the controller-based rotation but with reduced VR sickness and improved usability.

Spatial Contraction Based on Velocity Variation for Natural Walking in Virtual Reality.

Virtual Reality (VR) offers an immersive 3D digital environment, but enabling natural walking sensations without the constraints of physical space remains a technological challenge. Previous VR locomotion methods, including game controller, teleportation, treadmills, walking-in-place, and redirected walking (RDW), have made strides towards overcoming this challenge. However, these methods also face limitations such as possible unnaturalness, additional hardware requirements, or motion sickness risks. This paper introduces "Spatial Contraction (SC)", an innovative VR locomotion method inspired by the phenomenon of Lorentz contraction in Special Relativity. Similar to the Lorentz contraction, our SC contracts the virtual space along the user's velocity direction in response to velocity variation. The virtual space contracts more when the user's speed is high, whereas minimal or no contraction happens at low speeds. We provide a virtual space transformation method for spatial contraction and optimize the user experience in smoothness and stability. Through SC, VR users can effectively traverse a longer virtual distance with a shorter physical walking. Different from locomotion gains, the spatial contraction effect is observable by the user and aligns with their intentions, so there is no inconsistency between the user's proprioception and visual perception. SC is a general locomotion method that has no special requirements for VR scenes. The experimental results of our live user studies in various virtual scenarios demonstrate that SC has a significant effect in reducing both the number of resets and the physical walking distance users need to cover. Furthermore, experiments have also demonstrated that SC has the potential for integration with existing locomotion techniques such as RDW.

Design and Validation of Payload: Weight for a Bioinspired Inch Worm Wall Climbing Robot (IWWCR) Using Coppeliasim

In this growing era technology robots are replacing the humans by performing many risky operations enhancing the safety factor of human life. Particularly while considering performing task at high rise building or any high-altitude jobs, the need of wall climbing robot emerges. There are various types of wall climbing robot classified based on its adhesive mechanism and locomotive methods. Out of the various available method, Bioinspired type Robot has its own unique feature specifically when we talk about softbot. Bio inspired robots mimics the locomotion or any other specific feature of living creatures In this paper, an novel approach is introduced for design and development of a Bio inspired Wall Climbing Robot (WCR) using a simulation software named Coppelialsim. An inch worm wall climbing robot is proposed mimicking the locomotion of inch worm is proposed as novel design. The design of the proposed WCR is validated with respect to payload(p): weight (w) value using the static and dynamic analysis both in simulation environment using coppeliasim software and real time experimental testing after fabrication. The flow of electromagnetic flux is further justified with the software called Finite Element Magnetic Method (FEMM) and the structural design of the proposed design is validated with respect to the Computer Aided Analysis (CAA) software. Thus, the proposed IWWCR possess the high p: w value when compared to all other existing bioinspired Wall climbing Robot

Redirected walking for exploration of unknown environments

Real walking is the most natural locomotion method for exploring Virtual Environments (VE), enhancing the immersion of Virtual Reality (VR). Redirected Walking (RDW) is employed to enable real walking within limited tracking spaces in large VEs by subtly manipulating the mapping between the virtual and real environments. However, the effectiveness of RDW is greatly influenced by the convex shape and size of the manually defined physical tracking space, subsequently impacting the user’s immersive experience. To improve performance, one strategy is to integrate exploration methods from mobile robotics with RDW. This will expand the usable tracking space, facilitating dynamic environments and rapid exploration. For this, we adapted a Unity framework for an RDW algorithm to facilitate simulations for such an exploration. We conducted a simulation with artificially created non-convex explorable tracking spaces and pre-recorded path elements, simulating two adapted RDW artificial potential field (APF) concepts. Three conceptualized modes were applied: repulsive APF, exploration APF, and exploration APF with a distance threshold. Additionally, one APF was extended with a frontier-based exploration approach that utilized the path between the user’s position and a targeted frontier. The analysis revealed a significant trade-off between exploration and immersion. APF combined with frontier-based the exploration technique showed the fastest exploration speed, but - however - resulted in the lowest distance between resets.

Effects of caudal fin size on tail-flip jump performance

Fishes are generally considered to be fully aquatic, but some voluntarily strand themselves on land to escape poor water conditions, predators, or to exploit terrestrial niches. The tail-flip jump is a method of terrestrial locomotion performed by small fishes without apparent morphological specialization, but few studies have investigated the role the caudal fin has on the tail-flip jump. We hypothesized that fish with larger caudal fins would perform shorter individual tail-flip jumps and not be able to sustain jumping in extended terrestrial excursions. Zebrafish (Danio rerio) are an excellent model to investigate this because these fish perform the tail-flip jump and some strains have been selectively bred in the pet trade industry for larger fins. In this study, wildtype and longfin zebrafish were compared because of the larger caudal fins of the longfin zebrafish. Individuals of each strain performed three consecutive jump trials with 48 h between each trial: kinematic, voluntary, and exhaustion. The kinematic trial used a high-speed camera to measure kinematic variables of individual jumps. The voluntary trial recorded each fish’s voluntary response to stranding for three minutes. The exhaustion trial recorded the fish’s response to be constantly elicited to jump until exhaustion was reached. Despite differences in caudal fin area, there were no differences in the kinematic characteristics of individual jump performances, including jump distance. However, wildtype zebrafish performed more jumps, jumped more than they flopped, and moved a greater total distance in both voluntary and exhaustion trials despite moving for similar durations and reaching exhaustion at similar times. These findings imply that larger fins do not affect a fish’s ability to perform individual tail-flip jumps but does cause fish to employ different behavioral strategies when stranded for longer durations on land.

Leg Mechanism Design and Motion Performance Analysis for an Amphibious Crab-like Robot

Bionic-legged robots draw inspiration from animal locomotion methods and structures, demonstrating the potential to traverse irregular and unstructured environments. The ability of Portunus trituberculatus (Portunus) to run flexibly and quickly in amphibious environments inspires the design of systems and locomotion methods for amphibious robots. This research describes an amphibious crab-like robot based on Portunus and designs a parallel leg mechanism for the robot based on biological observations. The research creates the group and sequential gait commonly used in multiped robots combined with the form of the robot’s leg mechanism arrangement. This research designed the parallel leg mechanism and modeled its dynamics. Utilizing the outcomes of the dynamics modeling, we calculate the force and torque exerted on each joint of the leg mechanism during group gait and sequential gait when the robot is moving with a load. This analysis aims to assess the performance of the robot’s motion. Finally, a series of performance evaluation experiments are conducted on land and underwater, which show that the amphibious crab-like robot has good walking performance. The crab-like robot can perform forward, backward, left, and right walking well using group and sequential gaits. Simultaneously, the crab-like robot showcases faster movement in group gaits and a more substantial load capacity in sequential gaits.

Exploring the Relative Effects of Body Position and Locomotion Method on Presence and Cybersickness when Navigating a Virtual Environment

The primary goals of this research are to strengthen the understanding of the mechanisms underlying presence and cybersickness in relation to the body position and locomotion method when navigating a virtual environment (VE). In this regard, we compared two body positions (standing and sitting) and four locomotion methods (steering + embodied control [EC], steering + instrumental control [IC], teleportation + EC, and teleportation + IC) to examine the association between body position, locomotion method, presence, and cybersickness in VR. The results of a two-way ANOVA revealed a main effect of locomotion method on presence, with the sense of presence significantly lower for the steering + IC condition. However, there was no main effect of body position on presence, nor was there an interaction between body position and locomotion method. For cybersickness, nonparametric tests were used due to non-normality. The results of Mann-Whitney U tests indicated a statistically significant effect of body position on cybersickness. In particular, the level of cybersickness was significantly higher for a standing position than for a sitting position. In addition, the results of Kruskal-Wallis tests revealed that the locomotion method had a meaningful effect on cybersickness, with participants in the steering conditions feeling stronger symptoms of cybersickness than those in the teleportation conditions. Overall, this study confirmed the relationship between body position, locomotion method, presence, and cybersickness when navigating a VE.

A Systematic Literature Review of Virtual Reality Locomotion Taxonomies.

The change of the user's viewpoint in an immersive virtual environment, called locomotion, is one of the key components in a virtual reality interface. Effects of locomotion, such as simulator sickness or disorientation, depend on the specific design of the locomotion method and can influence the task performance as well as the overall acceptance of the virtual reality system. Thus, it is important that a locomotion method achieves the intended effects. The complexity of this task has increased with the growing number of locomotion methods and design choices in recent years. Locomotion taxonomies are classification schemes that group multiple locomotion methods and can aid in the design and selection of locomotion methods. Like locomotion methods themselves, there exist multiple locomotion taxonomies, each with a different focus and, consequently, a different possible outcome. However, there is little research that focuses on locomotion taxonomies. We performed a systematic literature review to provide an overview of possible locomotion taxonomies and analysis of possible decision criteria such as impact, common elements, and use cases for locomotion taxonomies. We aim to support future research on the design, choice, and evaluation of locomotion taxonomies and thereby support future research on virtual reality locomotion.

A comparison of two methods for moving through a virtual environment: walking in place and interactive redirected walking

Moving through a virtual environment that is larger than the physical space in which the participant operates has been a challenge since the early days of virtual reality. Many different methods have been proposed, such as joystick-based navigation, walking in place where the participant makes walking movements but is stationary in the physical space, and redirected walking where the environment is surreptitiously changed giving the illusion of walking in a long straight line in the virtual space but maybe a circle in the physical space. Each type of method has its limitations, ranging from simulator sickness to still requiring more physical space than is available. Stimulated by the COVID-19 lockdown, we developed a new method of locomotion which we refer to as interactive redirected walking. Here, the participant really walks but, when reaching a boundary, rotates the virtual world so that continuation of walking is always within the physical boundary. We carried out an exploratory study to compare this method with walking in place with respect to presence using questionnaires as well as qualitative responses based on comments written by the participants that were subjected to sentiment analysis. Surprisingly, we found that smaller physical boundaries favor interactive redirected walking, but for boundary lengths more than approximately 7 adult paces, the walking-in-place method is preferable.

Changes in Navigation over Time: A Comparison of Teleportation and Joystick-Based Locomotion

Little research has studied how people use Virtual Reality (VR) changes as they experience VR. This article reports the results of an experiment investigating how users’ behavior with two locomotion methods changed over 4 weeks: teleportation and joystick-based locomotion. Twenty novice VR users (with no more than 1 hour prior experience with any form of walking in VR) were recruited. They loaned an Oculus Quest for 4 weeks on their own time, including an activity we provided them with. Results showed that the time required to complete the navigation task decreased faster for joystick-based locomotion. Spatial memory improved with time, particularly when using teleportation (which starts disadvantaged to joystick-based locomotion). In addition, overall cybersickness decreased slightly over time; however, two dimensions of cybersickness (nausea and disorientation) increased notably over time using joystick-based navigation.

Locomotion performance of an axisymmetric ‘flapping fin’

Inspired by the jet-propulsion mechanism of aquatic creatures such as sea salps, a novel locomotion system based on an axisymmetric body design is proposed. This system consists of an empty tube with two ends open. When the diameters of the front and back openings are changed periodically, the forward-backward symmetry is broken so that the system starts swimming. Viewed within a cross section, this system resembles a two-dimensional flapping fin with its leading edge located at the front opening and the trailing edge at the back opening. The feasibility of this system has been proven via numerical simulations using a fluid-structure interaction model based on the immersed-boundary framework. According to the results, at relatively low Reynolds number (O(102)), this simple locomotion method can easily achieve a mean swimming speed of 2 to 3 body lengths per deformation period. Further simulations illustrate the following characteristics: (1) within the chamber, the hydrodynamic interactions among different parts of the body leads to a performance-enhancing mechanism similar to the ground effect; (2) reducing the diameter of the body can strengthen this effect so that both the swimming speed and the energy efficiency are improved; (3) for better performance the amplitude of diameter oscillation at the trailing edge should be larger or at least equal to the one at the leading edge.

Early developmental stages of a Lower Ordovician marrellid from Morocco suggest simple ontogenetic niche differentiation in early euarthropods

Early developmental stages of euarthropods are exceptionally rare in the fossil record. This hampers our understanding of the biology, phylogeny, and development of this extremely diverse metazoan group. Herein, we use classical paleontological methods in combination with synchrotron X-ray microtomography to explore the morphology in ca. 480 million-year-old early developmental stages of the Lower Ordovician Fezouata Shale marrellid euarthropod. These stages range between 3.8 and 5.3 mm in length and are characterized by three distinct pairs of gently curved spines that projects from the head shield. The first pair of cephalic appendages are represented by uniramous antenullae of a sensory function. The second pair of cephalic appendages is robust, and had an anchoring or stabilizing function. The third cephalic appendage pair is composed of long cylindrical podomeres and was used for walking. The trunk appendages are biramous and consist of an endopod and a lamellate exopod. Two anterior trunk endopods are composed of long slender podomeres and were used for walking, while the more posterior trunk endopods bear robust endites and associated setae and were used for food gathering. The trunk of the earliest developmental stages is composed of thirteen segments, in contrast to more than 22 segments in the adult trunk. The similar appendage morphology and differentiation along the body is evident in adult individuals of the Fezouata marrellid, suggesting these different developmental stages shared similar methods of locomotion and food processing. Given that adults and juveniles are often preserved in the same or nearby sites, the niche differentiation between these life stages would be the result of the absolute smaller appendage size in immature stages compared to larger adults, effectively differentiating the size of food resources consumed by each. In addition, the delicate setae present in the posterior trunk appendages of early developmental stages might have been used to capture smaller food particles. This simple mode of ontogenetic niche differentiation might have been common in the early diverging euarthropod groups.

Effects of Posture and Locomotion Methods on Postural Stability, Cybersickness, and Presence in a Virtual Environment

Virtual reality (VR) users experience unwanted symptoms, such as body imbalance, nausea, dizziness, and loss of presence. This study aims to investigate the effects of posture and locomotion on postural stability, cybersickness, and presence in VR environments. Twenty participants played a VR game under different conditions depending on posture (standing and sitting) and locomotion methods (joystick and teleportation), and seven dependent variables (COM, AP displacement, ML displacement, ASL, PSQ, VRSQ, and SOP) were analyzed to observe postural stability, cybersickness, and presence. The results revealed that postural instability increased when the task was performed in the standing posture with the joystick locomotion method compared to other conditions. The AP displacement, ML displacement, and ASL were lower under teleportation conditions. The PSQ scores indicated that postural stability was better in the sitting posture than in the standing posture. The VRSQ score revealed that the sitting with teleportation condition had less cybersickness than the other conditions. The SOP score was the highest in the standing posture with the teleportation condition. This study concludes that a sitting posture with teleportation locomotion can be considered when designing games in which users actively interact with virtual movements.

Research on Operation Conflict of Auxiliary Transport Locomotive in Complex Mine Based on Extended Petri Net

Aiming at the operation conflict problem of multi-objective, multi-path and multi-vehicle relay during mine locomotive operation under complex geological conditions, a mine operation of locomotive modeling method based on an object-oriented stratified timed Petri net is proposed. In order to load and transport materials as object oriented, which are combined with the mine operation of locomotive rules and time constraints, stratified modeling of an underground roadway route is carried out. In addition, given token time parameters to describe the dynamic behavior of the locomotive, through the model to analyze the operation of a mine transport locomotive, the correlation matrix and accessibility tree analysis are used to study the conflict. Taking the actual operation of a locomotive in a complex mine in Guizhou as an example, the operation of locomotive behavior model was established to detect the interval and time of operation conflicts. The experimental results show that the proposed operation of locomotive modeling and conflict analysis method are effective and feasible, and have important application value to the safe operation of a mine production system.

ManiLoco: A VR-Based Locomotion Method for Concurrent Object Manipulation.

The use of virtual reality (VR) in laboratory skill training is rapidly increasing. In such applications, users often need to explore a large virtual environment within a limited physical space while completing a series of hand-based tasks (e.g., object manipulation). However, the most widely used controller-based teleport methods may conflict with the users' hand operation and result in a higher cognitive load, negatively affecting their training experiences. To alleviate these limitations, we designed and implemented a locomotion method called ManiLoco to enable hands-free interaction and thus avoid conflicts and interruptions from other tasks. Users can teleport to a remote object's position by taking a step toward the object while looking at it. We evaluated ManiLoco and compared it with state-of-the-art Point & Teleport in a within-subject experiment with 16 participants. The results confirmed the viability of our foot- and head-based approach and better support concurrent object manipulation in VR training tasks. Furthermore, our locomotion method does not require any additional hardware. It solely relies on the VR head-mounted display (HMD) and our implementation of detecting the user's stepping activity, and it can be easily applied to any VR application as a plugin.