CoplayingVR: Understanding User Experience in Shared Control in Virtual Reality

Collaborative Virtual Reality (VR) systems increasingly rely on shared control mechanisms to enhance user coordination, but existing solutions often face trade-offs between individual autonomy and joint efficiency. This study builds on the foundational work of Zhou et al. (2024) on CoplayVR and PairPlayVR, aiming to optimize shared control by integrating adaptive authority allocation and real-time intent prediction. We conducted a user experiment with 32 participants, comparing the optimized mechanism against the baseline CoplayVR system across three collaborative tasks (object assembly, path navigation, and target selection). Results show that the optimized system reduces task completion time by 18.7% (p<0.05) and increases user satisfaction (SUS score: 82.3 vs. 71.5 for CoplayVR). Qualitative feedback further highlights improved perceived control and reduced coordination friction. This work advances shared control design for collaborative VR, complementing prior research on shared hand control and user experience in VR collaboration.

Extended-Reality Technologies: An Overview of Emerging Applications in Medical Education and Clinical Care.

Having a virtual body can increase embodiment in virtual reality (VR) applications. However, comsumer-grade VR falls short of delivering sufficient sensory information for full-body motion capture. Consequently, most current VR applications do not even show arms, although they are often in the field of view. We address this shortcoming with a novel human upper-body inverse kinematics algorithm specifically targeted at tracking from head and hand sensors only. We present heuristics for elbow positioning depending on the shoulder-to-hand distance and for avoiding reaching unnatural joint limits. Our results show that our method increases the accuracy compared to general inverse kinematics applied to human arms with the same tracking input. In a user study, participants preferred our method over displaying disembodied hands without arms, but also over a more expensive motion capture system. In particular, our study shows that virtual arms animated with our inverse kinematics system can be used for applications involving heavy arm movement. We demonstrate that our method can not only be used to increase embodiment, but can also support interaction involving arms or shoulders, such as holding up a shield.

The embodiment of avatars in virtual reality (VR) is a promising tool for enhancing the user’s mental health. A great example is the treatment of body image disturbances, where eliciting a full-body illusion can help identify, visualize, and modulate persisting misperceptions. Augmented reality (AR) could complement recent advances in the field by incorporating real elements, such as the therapist or the user’s real body, into therapeutic scenarios. However, research on the use of AR in this context is very sparse. Therefore, we present a holographic AR mirror system based on an optical see-through (OST) device and markerless body tracking, collect valuable qualitative feedback regarding its user experience, and compare quantitative results regarding presence, embodiment, and body weight perception to similar systems using video see-through (VST) AR and VR. For our OST AR system, a total of 27 normal-weight female participants provided predominantly positive feedback on display properties (field of view, luminosity, and transparency of virtual objects), body tracking, and the perception of the avatar’s appearance and movements. In the quantitative comparison to the VST AR and VR systems, participants reported significantly lower feelings of presence, while they estimated the body weight of the generic avatar significantly higher when using our OST AR system. For virtual body ownership and agency, we found only partially significant differences. In summary, our study shows the general applicability of OST AR in the given context offering huge potential in future therapeutic scenarios. However, the comparative evaluation between OST AR, VST AR, and VR also revealed significant differences in relevant measures. Future work is mandatory to corroborate our findings and to classify the significance in a therapeutic context.

PurposeWe describe two case studies that use embodiment in virtual reality as a treatment for chronic low back pain. The purpose of this case series was to determine the feasibility of a novel virtual reality-based digital therapeutic for the treatment of chronic pain.Patients and MethodsTwo patients with chronic low back pain received seven sessions, two sessions per week, of a novel digital therapeutic that combines virtual embodiment with graded motor imagery to deliver functional rehabilitation exercises using an off-the-shelf virtual reality system. Pain intensity was measured using a visual analog scale before and after each session to get an indication whether individual sessions of virtual embodiment training decrease pain intensity. Pain catastrophizing scale was assessed before the first session and after the seventh session to determine the extent to which virtual embodiment training can improve psychological symptoms of chronic low back pain.ResultsIn both patients, pain intensity was improved after individual sessions of virtual embodiment training as measured by a paired t-test: (Patient A: t = 2.890, P < 0.05) and (Patient B: t = 5.346, P < 0.005). This indicates that individual sessions of virtual embodiment training decrease pain intensity. In both patients, improvements were observed in three subscales of the pain catastrophizing scale (rumination, magnification, and helplessness). This indicates that virtual embodiment training may have benefits for chronic pain symptoms such as pain intensity, pain-related mobility impairment, and disability.ConclusionThis case series provides evidence that embodiment in virtual reality improves symptoms of persistent chronic low back pain. We propose a mechanism by which virtual embodiment may improve chronic pain symptoms by recontextualizing sensory feedback from the body as patients engage in functional rehabilitation exercises while in virtual reality.

Lower body tracking and user experience analysis are ongoing challenges in immersive technologies and biomechanics research, respectively. Particularly, in immersive technologies like mixed reality, there are limited research applications in user comfort and experience, and locomotion. In this paper, we aimed to conduct a cross-disciplinary research (by combining the elements of Biomechanics and human–computer interaction) in understanding the impact of user experience and immersive technologies induced symptoms in virtual and mixed reality environments for obstacle clearance tasks. For this, we created obstacle clearance applications for Oculus Quest and Microsoft HoloLens. Also, we conducted a user study with 12 participants under two conditions (virtual reality and mixed reality) in obstacle clearance behavior of varying heights. The results from our study indicated that the levels of immersion and enjoyment were significantly higher in virtual reality compared to mixed reality. In terms of virtual reality-induced symptoms, the participants found the mixed reality environment to be slightly more comfortable than virtual reality.

Fully autonomous robot systems, though highly desired, face substantial theoretical and practical challenges when being deployed into a dynamic environment where humans co-exist. To tackle this challenge, this thesis investigates the concept of human-in-the-loop (HITL) systems, which incorporate human input to enhance robot functionality. HITL systems offer a pragmatic alternative, combining human versatility with robotic precision. This research aims to address critical questions in one particular HITL architecture which prioritizes the dominant role of the human within the system, positioning the robot primarily in an assistive capacity that adheres to human commands to facilitate the achievement of a shared goal. It explores two primary paradigms of shared assistance methods-Shared Control (SC) and Shared Autonomy (SA)-and discusses the system designs as well as specific algorithms to implement the three critical components in a HITL system: human intention estimation, modulation of human inputs and robot autonomy, and the human-robot communication channel. Due to the variety of use cases and their unique challenges, four distinct HITL systems are developed and analyzed to illustrate how shared assistance methods could be employed to assist human operators: an assistive wheelchair for indoor navigation, a human-centered robot system design for industrial tasks, a mobile bi-manual robot for tele-manipulation, and a virtual reality (VR)-based customizable shared control system for fine teleoperation. Although each system represents a comprehensive robotic solution, the research contributions for each work vary. In the assistive wheelchair navigation system, the focus was on human intent estimation via a low-throughput interface utilizing a recursive Bayesian filter, with significant efforts dedicated to developing a real-time user interface serving as the communication channel. In the human-robot collaboration system for industrial setting, the emphasis was on human state estimation through camera-based posture tracking and exploring the interplay between robot behavior and human ergonomics. For the two teleoperation systems, the primary focus was on the real-time modulation of human inputs and robot autonomy to aid in achieving dexterous manipulation tasks. A novel VR-based user interface was developed to enable users to customize the robot autonomy level. Each system was validated through a pilot study involving 10-20 human subjects, accompanied by extensive data analysis to provide insights into designing HITL systems for various applications. In conclusion, this thesis contributes to a deeper understanding of HITL systems, highlighting their potential to enhance human productivity, ergonomics, and quality of life in varied applications through concrete examples. The integration of human intent estimation and real-time shared control methods into robotic systems demonstrates the feasibility and benefits of HITL approaches. Our extensive experimental analysis underscores the critical role of human feedback in designing practical HITL systems that can be deployed in real-world scenarios. --Author's abstract

Over the years, User Experience (UX) becomes a main term in designing an interactive product. The term itself lacks proper theoretical definition and is used in many different ways especially in academic and industry. This paper reviews and explores various existing approaches to conceptualize and understand user experience better. It covers both theories from the academics as well as studies conducted by the industries. Industries seem to treat user experience as a conventional usability while academics are more dynamic in defining user experience. Thus, this paper is trying to provide a base in conceptualizing and understanding user experience by covering different topics related to user experience.

Emerging technological innovations offer the potential for experiential engagement through virtual scenarios, yet the viability of this approach for educational purposes remains significantly underexplored. This study aims to assess the feasibility of Augmented Reality (AR) and Virtual Reality (VR) technologies in providing users with aesthetic experiences when visiting digital exhibitions. A total of 190 students participated in this investigation. The control group visited traditional exhibits at the Palace Museum in Beijing. This group underwent a survey to evaluate their acquired aesthetic experience. In contrast, the experimental group, comprising 96 students, engaged with VR/AR scenarios at the Palace Museum in Beijing. Accordingly, students in the experimental group were also surveyed to evaluate both their aesthetic experiences and, additionally, their user experiences. The survey results unveiled significant distinctions in aesthetic experiences between students in the control and experimental groups. Moreover, there were notable correlations between individual variables related to user and aesthetic experiences within the experimental group. Furthermore, the study revealed disparities in both user and aesthetic experiences among male and female students. The findings have implications for aesthetic education teachers and officials in the context of developing sound strategies for providing aesthetic experiences to their students. This information is also of interest to employees of museums, exhibitions, and other cultural facilities, who are interested in holding or hold digital exhibitions.

The ergonomic design of control elements in real life has been researched in detail. Various studies exist on the optimal dimensioning, their haptic and acoustic feedback to achieve high control accuracy and user experience. But the development of products is increasingly done with virtual prototypes. Virtual reality (VR) allows these prototypes to be tested in a highly immersive environment. However, the findings from reality cannot be transferred to VR directly. For example, users in VR interact with the prototypes using controllers, which affects haptic feedback. This study investigates how rotary dials and joysticks must be designed and programmed in VR so that control tasks can be performed efficiently and generate a high user experience and perceived presence.In user tests, subjects (n = 25) evaluate the control of a joystick and a rotary dial in VR. In a virtual crane operator's cabin or at a virtual table, the subjects (f = 10, m = 15, age: 24 +- 3) perform four predefined tasks per control element. On two screens in VR, subjects see a vertical bar graph with a scale from 0 to 100 % controlled by the joystick and separately a numerical value between 0 and 100 % which is controlled by the rotary dial. The screens display the task to the subjects, e.g., "Set the value from 0 % to 42 %". According to the method “design of experiments”, 14 factors, such as vibration feedback, acoustic feedback, position of the subject or the sensitivity of the control element are systematically varied on two respectively three levels (e.g., diameter of actuator 40 mm, 80 mm or 110 mm). For each trial, the control accuracy and the time required to complete the task are determined. In addition, the perceived presence is assessed using the Slater-Usoh-Steed-Questionnaire and the user experience is surveyed using the User Experience Questionnaire. The effect of a change of level on the response parameters is investigated using multifactorial ANOVA (α = .05). Linear regression is used to calculate a mathematical relationship between factor and response parameter. These mathematical models are used to calculate which factor values can be used to achieve a high level of control accuracy with a low time requirement and a high level of user experience and perceived presence. The factors angular resolution, inclination, shape of the rotary dial and position of the subject have a highly significant effect (p ≤ .001) on the time required to complete the tasks with the rotary dial. On the control accuracy of the rotary dial, the angular resolution, the VR-controller and the interaction of angular resolution and diameter of the rotary dial have a significant effect. On the user experience, a total of six factors and two interactions have a significant effect. On the perceived presence of the subjects, the VR environment and the diameter of the rotary dial have a significant effect. The calculated optimized design is a rotary dial with vibration feedback, without acoustic feedback, with visualization of a rough knurling, an angular resolution of 10-12 degree/value, a 40 mm diameter and no inclination. Visualization of the hand should be avoided.Sensitivity, size, subject position, VR environment, and the interaction of subject position and VR environment have a significant effect on the time required to perform the control tasks with the joystick. Three factors and one interaction have a significant effect on the control accuracy of the joystick. The interaction of the factors vibration feedback and visualization of the hand has a significant effect on the perceived presence of the subjects. On user experience, nine factors and five interactions have a significant effect. The calculated optimized levels of factors for the joystick are vibration and acoustic feedback, no visual feedback, vertical handle with a height of 20-24 cm, a five-level angular resolution, a maximum deflection angle of +- 15°, a sensitivity of 8 %/sec and a visualization of the hand.The trials show a high degree of scatter. The residuals show outliers in the experiments. These deviations are mainly due to the individual previous experience of the test subjects in handling VR systems. Nevertheless, significant effects could be identified. A screening experimental design was used in this study. In a follow-up study, detailed investigations with a full factorial experimental design must be performed with the significant factors. The factors will be tested at multiple levels and with a significantly increased number of trials to further increase the accuracy of the mathematical models.

Objective: This study evaluates the usability in accordance with EN 62366 of the True Dose kit for capillary blood self-sampling, to be used to analyze, specify, design, verify, and validate usability as it relates to the safety of medical devices focusing on user performance, experience, and user confidence through a mixed-methods approach. The usability engineering process is needed to fulfill user interface design requirements as part of product development at True Dose kit. Methods: The study employed a convergent parallel design, integrating quantitative and qualitative data. Twenty-five participants, recruited through convenience sampling, used the True Dose kit to perform capillary blood self-sampling. Quantitative data were collected using three key performance metrics-collection of sufficient blood volume, absence of air bubbles, and duration of the self-sampling process-along with two questionnaires, the System Usability Scale (SUS) and the Test Feedback Questionnaire (TFQ), to comprehensively assess user performance and experience. In contrast, qualitative data were obtained from interviews and free-text responses. The integration of findings highlighted areas of convergence and divergence between the quantitative and qualitative data. Results: The overall SUS score was 82.70, indicating high usability. However, participants reported challenges with the complexity of instructions and stress associated with blood flow management. Qualitative insights revealed a preference for simplified visual guidance and highlighted the need for precise feedback mechanisms to ensure the correct execution of sampling steps. Despite these challenges, 92% of participants collected the required blood sample, with a median self-sampling duration of 10.42 min. Conclusion: The True Dose kit demonstrates high usability potential, but improvements in instructional design and stress management are needed to enhance user experience and ensure consistent performance. Trial Registration: EUCT Number: 2024-514818-12-00.

The fast growth of virtual reality (VR) and augmented reality (AR) head-mounted displays provides a new medium for interactive visualisations and visual analytics. Presence is the experience of consciousness within extended reality, and it has the potential to increase task performance. This project studies the impact that a sense of presence has on data visualisation performance and user experience under AR and VR conditions. A within-subjects design recruited 38 participants to complete interactive visualisation tasks within the novel immersive data analytics system for genomic data in AR and VR, and measured speed, accuracy, preference, presence, and user satisfaction. Open-ended user experience responses were also collected. The results implied that VR was more conducive to efficiency, effectiveness, and user experience as well as offering insight into possible cognitive load benefits for VR users.

The hands of one's avatar are possibly the most visible aspect when interacting in virtual reality (VR). As video games in VR proliferate, it is important to understand how the appearance of avatar hands influence the user experience. Designers of video games often stylize hands and reduce the number of fingers of game characters. Previous work shows that the appearance of avatar hands has significant effects on the user's presence - the feeling of `being' and `acting' in VR. However, little is known about the effects of missing fingers of an avatar in VR. In this paper, we present a study (N=24) that investigated the effect of hand representations by parametrically varying the number of fingers of abstract and realistically rendered hands. We show that decreasing the number of fingers of realistic hands leads to significantly lower levels of presence, which is not the case for abstract hands. Qualitative feedback collected through think-aloud and video revealed potential reasons for the different assessment of realistic and abstract hands with fewer fingers in VR. We contribute design implications and recommend considering the human-likeness when a reduction of the number of fingers of avatar hands is desired.

Rendering haptic feedback on the wrist is an effective solution for freeing users' hands during virtual interactions while still providing haptic feedback, mostly focusing on Virtual Reality (VR) environments. Unfortunately, whether these solutions can be extended to Augmented Reality (AR) interactions has not been investigated before. In this paper, we investigate the perceptual differences between VR and AR environments with a user study experiment based on a stiffness discrimination task. Our findings revealed similar task accuracy and sensitivity in VR and AR but different exploration behaviors (i.e. higher interaction time in AR) and user experience (i.e. higher enjoyment and less mental fatigue in AR). These differences may be explained by the increased cognitive load and the environmental immersion in AR, where users navigate both virtual and real elements simultaneously. This suggests that visuo-haptic psychophysical findings obtained in VR can be extended to AR, even though user experience and exploration behavior might differ.

Do VR and AR versions of an immersive cultural experience engender different user experiences?