The Experts below are selected from a list of 90 Experts worldwide ranked by ideXlab platform
Antonio Franchi - One of the best experts on this subject based on the ideXlab platform.
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Towards Aerial Physical Locomotion: the Contact-Fly-Contact Problem
IEEE Robotics and Automation Letters, 2018Co-Authors: Quentin Delamare, Paolo Robuffo Giordano, Antonio FranchiAbstract:In this paper we consider the problem of letting an aerial robot exploiting its contact with the environment in order to enhance its motion possibilities, in a way reminiscent of legged robots exploiting contact forces for Locomotion purposes. As a representative and initial case study, we consider a quadrotor equipped with a 1-DOF arm able to hook at some pivot points, and needing to perform a maneuver from an initial hooked configuration to a final hooked configuration while passing though a free-flight phase between the two anchor points. To this end, we propose a dynamical modeling able to capture the various phases (hooked, free-flying) together with an optimization framework for generating optimal motion plans compatible with actuation constraints. Simulation results illustrate the effectiveness of the approach and the promising potential in terms of more advanced maneuvers.
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Toward Aerial Physical Locomotion: The Contact-Fly-Contact Problem
IEEE Robotics and Automation Letters, 2018Co-Authors: Quentin Delamare, Paolo Robuffo Giordano, Antonio FranchiAbstract:In this letter, we consider the problem of letting an aerial robot exploiting its contact with the environment in order to enhance its motion possibilities, in a way reminiscent of legged robots exploiting contact forces for Locomotion purposes. As a representative and initial case study, we consider a quadrotor equipped with a 1-degree of freedom (DOF) arm able to hook at some pivot points, and needing to perform a maneuver from an initial hooked configuration to a final hooked configuration while passing though a free-flight phase between the two anchor points. To this end, we propose a dynamical modeling able to capture the various phases (hooked, free-flying) together with an optimization framework for generating optimal motion plans compatible with actuation constraints. Simulation results illustrate the effectiveness of the approach and the promising potential in terms of more advanced maneuvers.
Quentin Delamare - One of the best experts on this subject based on the ideXlab platform.
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Towards Aerial Physical Locomotion: the Contact-Fly-Contact Problem
IEEE Robotics and Automation Letters, 2018Co-Authors: Quentin Delamare, Paolo Robuffo Giordano, Antonio FranchiAbstract:In this paper we consider the problem of letting an aerial robot exploiting its contact with the environment in order to enhance its motion possibilities, in a way reminiscent of legged robots exploiting contact forces for Locomotion purposes. As a representative and initial case study, we consider a quadrotor equipped with a 1-DOF arm able to hook at some pivot points, and needing to perform a maneuver from an initial hooked configuration to a final hooked configuration while passing though a free-flight phase between the two anchor points. To this end, we propose a dynamical modeling able to capture the various phases (hooked, free-flying) together with an optimization framework for generating optimal motion plans compatible with actuation constraints. Simulation results illustrate the effectiveness of the approach and the promising potential in terms of more advanced maneuvers.
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Toward Aerial Physical Locomotion: The Contact-Fly-Contact Problem
IEEE Robotics and Automation Letters, 2018Co-Authors: Quentin Delamare, Paolo Robuffo Giordano, Antonio FranchiAbstract:In this letter, we consider the problem of letting an aerial robot exploiting its contact with the environment in order to enhance its motion possibilities, in a way reminiscent of legged robots exploiting contact forces for Locomotion purposes. As a representative and initial case study, we consider a quadrotor equipped with a 1-degree of freedom (DOF) arm able to hook at some pivot points, and needing to perform a maneuver from an initial hooked configuration to a final hooked configuration while passing though a free-flight phase between the two anchor points. To this end, we propose a dynamical modeling able to capture the various phases (hooked, free-flying) together with an optimization framework for generating optimal motion plans compatible with actuation constraints. Simulation results illustrate the effectiveness of the approach and the promising potential in terms of more advanced maneuvers.
Betsy Williams - One of the best experts on this subject based on the ideXlab platform.
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SAP - Leaning as a method of translation in large virtual environments
Proceedings of the ACM Symposium on Applied Perception, 2013Co-Authors: Alyssa Harris, Preston Tunnell Wilson, Kevin Nguyen, Betsy WilliamsAbstract:Research has shown that virtual environments (VEs) are best explored on foot. However, when a person uses their own Physical Locomotion to explore a VE, they are limited by the range of the tracking system or the size of the Physical room housing the tracking system. This poster presents a new method of exploring a large VE using a head-mounted display (HMD). Specifically, we examine the idea of Physically leaning or tilting as a means of translating the user forward in the virtual space. The feasibility and accuracy of this system is tested by directly comparing it to joystick navigation, where virtual translations are accomplished by pushing the joystick forward. In both methods, Physical rotations correspond to virtual rotations and users translate forward in the yaw angle they are facing.
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SAP - Exploring a virtual environment by walking in place using the Microsoft Kinect
Proceedings of the ACM Symposium on Applied Perception - SAP '12, 2012Co-Authors: Ye Zheng, Matthew Mccaleb, Courtney Strachan, Betsy WilliamsAbstract:When using a head-mounted display (HMD) to explore a virtual environment (VE), it is useful to navigate on foot. This aids spatial awareness because it provides the inertial cues related to Physical Locomotion. However, the size of the virtual environment that can be Physically explored on foot can be no larger than the limits of the tracking system. One way to permit free exploration of any size virtual environment and provide some of the inertial cues of walking is to have the users "walk in place" (WIP)[Slater et al. 1995; Feasel et al. 2008; Williams et al. 2011]. With WIP, each step is treated as a translation of a distance even though the participant remains in the same location. In our prior work [Williams et al. 2011], we had success in implementing a WIP method using an inexpensive Nintendo Wii Balance Board and we showed that participants' spatial orientation was the same as normal walking and superior to joystick navigation. There were two major drawbacks of our previous WIP algorithm. First, our step detection algorithm had a half-step lag. Second, it was slightly annoying for participants to walk in place on the small board. Thus, the current work seeks to use overcome these limitations by presenting an algorithm to WIP using the Microsoft Kinect sensor. This technology is readily available to the public for around 150 USD.
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APGV - Exploring large virtual environments with an HMD when Physical space is limited
Proceedings of the 4th symposium on Applied perception in graphics and visualization - APGV '07, 2007Co-Authors: Betsy Williams, Gayathri Narasimham, Bjoern Rump, Timothy P. Mcnamara, Thomas H. Carr, John J. Rieser, Bobby BodenheimerAbstract:Virtual Environments presented through head-mounted displays (HMDs) are often explored on foot. Exploration on foot is useful since the afferent and efferent cues of Physical Locomotion aid spatial awareness. However, the size of the virtual environment that can be explored on foot is limited to the dimensions of the tracking space of the HMD unless other strategies are used. This paper presents a system for exploring a large virtual environment on foot when the size of the Physical surroundings is small by leveraging people's natural ability to spatially update. This paper presents three methods of "resetting" users when they reach the Physical limits of the HMD tracking system. Resetting involves manipulating the users' location in Physical space to move them out of the path of the Physical obstruction while maintaining their spatial awareness of the virtual space.
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APGV - Exploring large virtual environments with an HMD on foot
Proceedings of the 3rd symposium on Applied perception in graphics and visualization - APGV '06, 2006Co-Authors: Betsy Williams, Gayathri Narasimham, Bjoern Rump, Timothy P. Mcnamara, Thomas H. Carr, John J. Rieser, Bobby BodenheimerAbstract:Virtual Environments presented through head-mounted displays (HMDs) are often explored on foot. Exploration on foot is useful since the inertial cues of Physical Locomotion aid spatial awareness. However, the size of the virtual environment that can be explored on foot is limited to the dimensions of the tracking space of the HMD, unless gain is scaled [Williams et al. 2006]. This work explores methods of remedying this limitation by changing the location of a user in Physical space while maintaining their spatial awareness of their virtual space, a technique we call "resetting". Resetting involves Physical Locomotion with optical manipulated flow in such a way that the user's sense of where they are relative to objects in their virtual environment is not changed. We assess three plausible methods of resetting.
Bobby Bodenheimer - One of the best experts on this subject based on the ideXlab platform.
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HCI (9) - Scaling Gain and Eyeheight While Locomoting in a Large VE
Virtual Augmented and Mixed Reality. Multimodal Interaction, 2019Co-Authors: Betsy Williams-sanders, Gayathri Narasimham, Timothy P. Mcnamara, Thomas H. Carr, John J. Rieser, Bobby BodenheimerAbstract:Virtual Environments (VEs) presented through head-mounted displays (HMDs) are often explored on foot. This type of exploration is useful since the inertial cues of Physical Locomotion aid spatial awareness. However, the size of the VE that can be explored on foot is limited to the dimensions of the tracking space of the HMD unless Locomotion is somehow manipulated. This paper presents a system for exploring a large VE on foot when the size of the Physical surroundings is small by leveraging people’s natural ability to maintain spatial awareness using their own Locomotion. We examine two strategies to increase the explorable size of the virtual space: scaling the translational gain of walking and scaling eyeheight. Translational gain is scaled by changing the relationship between Physical and visual translation so that one step forward in Physical space corresponds to several steps forward in virtual space. To scale gain higher than ten, it becomes necessary to investigate ways to minimize distracting small Physical head motions. We present such a method here. We examine a range of scaling factors and find that we can expect to scale translational gain by a factor of 50. In addition to this finding, this paper also investigates whether scaling eyeheight proportionally to gain increases spatial awareness. We found that providing a map-like overview of the environment does not increase the user’s spatial orientation in the VE.
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APGV - Exploring large virtual environments with an HMD when Physical space is limited
Proceedings of the 4th symposium on Applied perception in graphics and visualization - APGV '07, 2007Co-Authors: Betsy Williams, Gayathri Narasimham, Bjoern Rump, Timothy P. Mcnamara, Thomas H. Carr, John J. Rieser, Bobby BodenheimerAbstract:Virtual Environments presented through head-mounted displays (HMDs) are often explored on foot. Exploration on foot is useful since the afferent and efferent cues of Physical Locomotion aid spatial awareness. However, the size of the virtual environment that can be explored on foot is limited to the dimensions of the tracking space of the HMD unless other strategies are used. This paper presents a system for exploring a large virtual environment on foot when the size of the Physical surroundings is small by leveraging people's natural ability to spatially update. This paper presents three methods of "resetting" users when they reach the Physical limits of the HMD tracking system. Resetting involves manipulating the users' location in Physical space to move them out of the path of the Physical obstruction while maintaining their spatial awareness of the virtual space.
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APGV - Exploring large virtual environments with an HMD on foot
Proceedings of the 3rd symposium on Applied perception in graphics and visualization - APGV '06, 2006Co-Authors: Betsy Williams, Gayathri Narasimham, Bjoern Rump, Timothy P. Mcnamara, Thomas H. Carr, John J. Rieser, Bobby BodenheimerAbstract:Virtual Environments presented through head-mounted displays (HMDs) are often explored on foot. Exploration on foot is useful since the inertial cues of Physical Locomotion aid spatial awareness. However, the size of the virtual environment that can be explored on foot is limited to the dimensions of the tracking space of the HMD, unless gain is scaled [Williams et al. 2006]. This work explores methods of remedying this limitation by changing the location of a user in Physical space while maintaining their spatial awareness of their virtual space, a technique we call "resetting". Resetting involves Physical Locomotion with optical manipulated flow in such a way that the user's sense of where they are relative to objects in their virtual environment is not changed. We assess three plausible methods of resetting.
Omar Janeh - One of the best experts on this subject based on the ideXlab platform.
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Human Gait in Virtual Reality : Analyses & Changes of Gait during Locomotion in Immersive Virtual Environments
2020Co-Authors: Omar JanehAbstract:Bipedal walking is generally considered to be the most natural and common Locomotion technique for humans in the Physical world, and the most presence-enhancing form of Locomotion in virtual reality (VR). However, there are significant differences in the way people walk in VR compared to their walking behaviour in the real world. Understanding real walking in virtual environments (VEs) is important for immersive experiences, allowing users to move through VEs in the most intuitive natural way. Previous studies have shown that basic implementations of real walking in virtual spaces, in which head-tracked movements are mapped isometrically to a VE, are not estimated as entirely natural. Instead, users estimate a virtual walking velocity as more natural when it is slightly increased compared to the user's Physical Locomotion. Indeed, these findings have been reported in most cases only for young persons, in particular, students, whereas older adults are clearly underrepresented in such studies. However, it appears reasonable to assume that more and more people at different ages will have access to VR, and might use this technology in application scenarios such as physiotherapy, rehabilitation or training. In this context, due to its high personal and economical impact, gait disturbances have become a main focus of interest in Parkinson’s disease research. Therapeutic options of medication or deep brain surgery are limited, therefore Physical training strategies have evolved to be a focus of interest to improve gait and freezing of gait. This dissertation focuses on three aspects: (i) analyses and evaluation of the differences of gait parameters between a real and virtual environments, and furthermore investigation of how walking in VEs during (non-)isometric mappings varies across generations, i.e., healthy younger and older adults, with the goal to understand the perceptual and motor differences. (ii) Analyses of changes in velocity over time while walking within a VE and the real world with and without additional cognitive task. In particular, we performed a controlled user study to investigate Locomotion adaptation over time due to prolonged exposure to these conditions. (iii) Study and treatment of gait asymmetry. In particular, we developed different virtual walking manipulation techniques to overcome the pathological spatial asymmetry of Parkinson’s disease patients with respect to step length. In der realen Welt wird das Laufen auf zwei Beinen als die naturlichste und verbreitetste Fortbewegung angesehen. In der virtuellen Realitat (VR) gilt sie als die Fortbewegungsart, die das Gefuhl von Presence am meisten verstarkt. Jedoch gibt es grose Unterschiede zwischen der Art, wie Menschen in VR laufen, und ihrem Laufverhalten in der wirklichen Welt. Fur immersive VR-Experiences ist es wichtig, reales Laufen in virtuellen Umgebungen (Virtual Environments, VEs) zu verstehen, um den Nutzern eine moglichst naturliche Fortbewegung durch die VE zu ermoglichen. Vorherige Studien haben gezeigt, dass einfache Implementierungen von realem Laufen in virtuellen Raumen, bei denen mittels Kopf-Tracking gemessene Bewegungen isometrisch auf eine VE gemappt werden, sich nicht komplett naturlich anfuhlen. Stattdessen schatzen Nutzer die virtuelle Laufgeschwindigkeit als naturlicher ein, wenn sie im Vergleich zu der physischen Fortbewegung des Nutzers leicht erhoht ist. Diese Beobachtungen wurden jedoch grostenteils nur bei jungen Menschen gemacht, insbesondere bei Studierenden, wohingegen altere Erwachsene in solchen Studien deutlich unterreprasentiert sind. Man kann jedoch annehmen, dass mehr und mehr Menschen unterschiedlichen Alters Zugang zu VR erhalten und diese Technologie auch im Rahmen von Anwendungsszenarien wie Physiotherapie, Rehabilitation und Training nutzen werden. In diesem Zusammenhang sind Gangstorungen aufgrund der enormen personlichen und wirtschaftlichen Auswirkungen in den Fokus der Parkinson-Forschung geruckt. Die Moglichkeiten einer Therapie durch Medikamente oder tiefe Hirnchirurgie sind beschrankt, weshalb Strategien fur korperliches Training, mit denen das Gangbild und das Einfrieren des Gangs verbessert werden sollen, zum Forschungsschwerpunkt geworden sind. Diese Dissertation konzentriert sich auf drei Aspekte: (i) Analyse und Bewertung der Gangparameter, die sich zwischen realen und virtuellen Umgebungen unterscheiden, sowie die Frage, wie sich Laufen in VEs aufgrund (nicht-)isometrischer Mappings zwischen den Generationen - also jungeren und alteren Erwachsenen - unterscheidet. Ziel ist hier, die perzeptuellen und motorischen Unterschiede zu verstehen. (ii) Analyse von allmahlichen Veranderungen der Geschwindigkeit beim Laufen innerhalb einer VR und in der realen Welt mit und ohne kognitive Aufgabe. Insbesondere wurde eine kontrollierte Nutzerstudie durchgefuhrt, um allmahliche Anpassungen der Fortbewegung zu untersuchen, wenn die Nutzer diesen Bedingungen langer ausgesetzt sind. (iii) Untersuchung und Behandlung der Gangasymmetrie. Insbesondere wurden unterschiedliche Techniken entwickelt, den Gang virtuell zu manipulieren, um die pathologische raumliche Asymmetrie von Parkinson-Patienten in Bezug auf die Schrittlange auszugleichen.
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Analyses of Gait Parameters of Younger and Older Adults During (Non-)Isometric Virtual Walking
IEEE transactions on visualization and computer graphics, 2017Co-Authors: Omar Janeh, Gerd Bruder, Frank Steinicke, Alessandro Gulberti, Monika Poetter-nergerAbstract:Understanding real walking in virtual environments (VEs) is important for immersive experiences, allowing users to move through VEs in the most natural way. Previous studies have shown that basic implementations of real walking in virtual spaces, in which head-tracked movements are mapped isometrically to a VE, are not estimated as entirely natural. Instead, users estimate a virtual walking velocity as more natural when it is slightly increased compared to the user’s Physical Locomotion. However, these findings have been reported in most cases only for young persons, e.g., students, whereas older adults are clearly underrepresented in such studies. Recently, virtual reality (VR) has received significant public and media attention. Therefore, it appears reasonable to assume that people at different ages will have access to VR, and might use this technology more and more in application scenarios such as rehabilitation or training. To better understand how people at different ages walk and perceive Locomotion in VR, we have performed a study to investigate the effects of (non-)isometric mappings between Physical movements and virtual motions in the VE on the walking biomechanics across generations, i.e., younger and older adults. Three primary domains (pace, base of support and phase) of spatio-temporal parameters were identified to evaluate gait performance. The results show that the older adults walked very similar in the real and VE in the pace and phasic domains, which differs from results found in younger adults. In contrast, the results indicate differences in terms of base of support domain parameters for both groups while walking within a VE and the real world. For non-isometric mappings, we found in both younger and older adults an increased divergence of gait parameters in all domains correlating with the up- or down-scaled velocity of visual self-motion feedback. The results provide important insights into the design of future VR applications for older adults in domains ranging from medicine and psychology to rehabilitation.