Mixed reality (MR)opens up new vistas for human-robot interaction (HRI)scenarios in which a human operator can control and collaborate with co-located robots. For instance, when using a see-through head-mounted-display (HMD)such as the Microsoft HoloLens, the operator can see the real robots and additional virtual information can be superimposed over the real-world view to improve security, acceptability and predictability in HRI situations. In particular, previewing potential robot actions in-situ before they are executed has enormous potential to reduce the risks of damaging the system or injuring the human operator. In this paper, we introduce the concept and implementation of such an MR human-robot collaboration system in which a human can intuitively and naturally control a co-located industrial robot arm for pick-and-place tasks. In addition, we compared two different, multimodal HRI techniques to select the pick location on a target object using (i)head orientation (aka heading)or (ii)pointing, both in combination with speech. The results show that heading-based interaction techniques are more precise, require less time and are perceived as less physically, temporally and mentally demanding for MR-based pick-and-place scenarios. We confirmed these results in an additional usability study in a delivery-service task with a multi-robot system. The developed MR interface shows a preview of the current robot programming to the operator, e. g., pick selection or trajectory. The findings provide important implications for the design of future MR setups.

Real walking in virtual reality (VR) is a promising locomotion technique since it offers multi-modal feedback to the user. Unfortunately, the virtual environment (VE) is limited by the available space in the physical world. So far, several techniques were developed to overcome this problem, e. g. redirected walking (RDW) and the use of impossible spaces. RDW subtly manipulates the viewpoint of the user to reorient her walking direction. Impossible spaces are based on subtle changes of the VE to reuse the same physical space for different virtual spaces. In this research demonstration, we show how these two approaches of redirected walking and impossible spaces can be combined. In particular, for our implementation we focus on the use of curved corridors that benefits both methods.

Animating with keyframes gives animators a lot of control but they can be tedious and complicated to work with. Currently, different solutions try to simplify animation creation by recording the natural hand movements of the user. However, most of the solutions are bound to 2D animations [1] or suffer from a low workflow speed [4]. The proposed Unity plugin AnimationVR uses the HTC Vive system to enable the puppeteering animation technique in VR while still allowing for a fast workflow speed by utilizing the 6DOF controllers. During storyboarding or rapid prototyping, the user can immediately see the results of their actions. Also, Animation Vr is written for easy integration in already existing Unity projects. The plug in was evaluated by four animation experts who agreed that Animation Vr accelerates the workflow while decreasing the animation precision. This trade-off makes it useful for storyboarding in professional environments. The experts also noted the ease of use of the puppeteering technique which could enable beginners to create complex animations without any experience with animating.

Animating with keyframes gives animators a lot of control but they can be tedious and complicated to work with. Currently, different solutions try to simplify animation creation by recording the natural hand movements of the user. However, most of the solutions are bound to 2D animations [1] or suffer from a low workflow speed [2]. The proposed Unity plugin Animation Vr uses the HTC Vive system to enable the puppeteering animation technique in VR while still allowing for a fast workflow speed by utilizing the controllers of the VR system. Also, Animation Vr is written for easy integration in already existing Unity projects. The plugin was evaluated with four animation experts. The consensus was that Animation Vr increases the workflow speed while decreasing the animation precision. This tradeoff makes it useful for storyboarding in professional environments. Additionally, the plugin could improve the understanding of VR storytelling as the animators would create and instantly review the animations in the correct medium. The experts also noted the ease of use of the puppeteering technique which could enable beginners to create complex animations with little to no experience with Animation Vr. Additionally, the accessibility for animation beginners could improve the communication in animation teams between animators and directors.

This work is observing the impacts/influence of different mapping functions between the user's flick gesture and the animation of the flicked object. The flick gesture, in which the user quickly swipes a finger across the screen and lifts the finger without slowing down, is a popular interaction technique on multitouch displays, e. g. for navigating on digital maps. While flick operations are well established on small mobile touch screens, the exact implementation of this technique on large multitouch tabletops needs to be adjusted to several parameters, especially flick velocity and inertia duration.

Redirected walking (RDW) promises to allow near-natural walking in an infinitely large virtual environment (VE) by subtle manipulations of the virtual camera. Previous experiments showed that a physical radius of at least 22 meters is required for undetectable RDW. However, we found that it is possible to decrease this radius and to apply RDW to room-scale VR, i. e., up to approximately 5m × 5m. This is done by using curved paths in the Ve instead of straight paths, and by coupling them together in a way that enables continuous walking. Furthermore, the corresponding paths in the real world are laid out in a way that fits perfectly into room-scale VR. In this research demo, users can experience RDW in a room-scale head-mounted display VR setup and explore a VE of approximately 25m × 25m.

Redirected walking (RDW) promises to allow near-natural walking in an infinitely large virtual environment (VE) by subtle manipulations of the virtual camera. Previous experiments analyzed the human sensitivity to RDW manipulations by focusing on the worst-case scenario, in which users walk perfectly straight ahead in the VE, whereas they are redirected on a circular path in the real world. The results showed that a physical radius of at least 22 meters is required for undetectable RDW. However, users do not always walk exactly straight in a VE. So far, it has not been investigated how much a physical path can be bent in situations in which users walk a virtual curved path instead of a straight one. Such curved walking paths can be often observed, for example, when users walk on virtual trails, through bent corridors, or when circling around obstacles. In such situations the question is not, whether or not the physical path can be bent, but how much the bending of the physical path may vary from the bending of the virtual path. In this article, we analyze this question and present redirection by means of bending gains that describe the discrepancy between the bending of curved paths in the real and virtual environment. Furthermore, we report the psychophysical experiments in which we analyzed the human sensitivity to these gains. The results reveal encouragingly wider detection thresholds than for straightforward walking. Based on our findings, we discuss the potential of curved walking and present a first approach to leverage bent paths in a way that can provide undetectable RDW manipulations even in room-scale VR.

This video presents the experimental setup of an immersive flight simulation system, which combines body tracking with a head-mounted display. Users are hanging freely in a climbing harness in order to improve the impression to fly. The base system was created by a group of students during one semester as a bachelor project. A study revealed that a high degree of presence is achievable by the combination of body-posture based control and 3D visualization via a head-mounted display while hanging freely in a climbing gear. Furthermore the results of a study that compares two different steering methods are presented. Both control methods seem to be quite interesting and intuitively controllable but show individual preferences among the participants of the study. In our experiments very frequently strong vaction effects were reported when flying turns to one side. The setup very likely causes simulator sickness, especially if a participant was bad in controlling his flight.

Redirected walking allows users to walk through a large-scale immersive virtual environment (IVE) while physically remaining in a reasonably small workspace. Therefore, manipulations are applied to virtual camera motions so that the user's self-motion in the virtual world differs from movements in the real world. Previous work found that the human perceptual system tolerates a certain amount of inconsistency between proprioceptive, vestibular and visual sensation in IVEs, and even compensates for slight discrepancies with recalibrated motor commands. Experiments showed that users are not able to detect an inconsistency if their physical path is bent with a radius of at least 22 meters during virtual straightforward movements. If redirected walking is applied in a smaller workspace, manipulations become noticeable, but users are still able to move through a potentially infinitely large virtual world by walking. For this semi-natural form of locomotion, the question arises if such manipulations impose cognitive demands on the user, which may compete with other tasks in IVEs for finite cognitive resources. In this article we present an experiment in which we analyze the mutual influence between redirected walking and verbal as well as spatial working memory tasks using a dual-tasking method. The results show an influence of redirected walking on verbal as well as spatial working memory tasks, and we also found an effect of cognitive tasks on walking behavior. We discuss the implications and provide guidelines for using redirected walking in virtual reality laboratories.