Perceiving Aperture Widths During Teleoperation

When teleoperating robots it is often difficult for operators to perceive aspects of remote environments within which they are working (Tittle, Roesler, & Woods, 2002). It is difficult to perceive the sizes of objects in remote environments and to determine if the robot can pass through apertures of various sizes (Casper & Murphy, 2003; Murphy 2004). The present experiment investigated whether remote perception could be improved by providing optic flow during robot movement or by positioning an on-board camera so that the forward portion the robot is in the camera\u27s view. Participants judges the sizes of remote apertures viewed through a camera mounted on a remote robot. The participants were divided into two different viewing conditions; those with the forward portion of the robot in view and those without any portion of the robot in view. Each participant viewed a series of 60 videos, some of which provided optic flow and some of which did not. Results indicated no differences between the flow conditions, and a small yet statistically significant difference between the viewing conditions. On average the participants judged the apertures to be larger when the robot was not in view, which could lead to operators overestimating the ability of robots to fit through small openings. The implications of these findings for the teleoperation of remote robots are discussed

Just Around the Corner: The Impact of Instruction Method and Corner Geometry on Teleoperation of Virtual Unmanned Ground Vehicles

Teleoperated robots have proven useful across various domains, as they can more readily search for survivors, survey collapsed and structurally unsound buildings, map out safe routes for rescue workers, and monitor rescue environments. A significant drawback of these robots is that they require the operator to perceive the environment indirectly. As such, camera angles, uneven terrain, lighting, and other environmental conditions can result in robots colliding with obstacles, getting stuck in rubble, and falling over (Casper & Murphy, 2003). To better understand how operators remotely perceive and navigate unmanned ground vehicles, the present work investigated operators’ abilities to negotiate corners of varying widths. In Experiment 1, we evaluated how instruction method impacts cornering time and collisions, looking specifically at the speed-accuracy tradeoff for negotiating corners. Participants navigated a virtual vehicle around corners under the instruction to focus on accuracy (i.e., avoiding collisions) or speed (i.e., negotiating the corners as quickly as possible). We found that as the task became more difficult, subjects’ cornering times increased, and their probability of successful cornering decreased. We also demonstrated that the Fitts’ law speed-accuracy tradeoff could be extended to a cornering task. In Experiment 2, we challenged two of the assumptions of Pastel et al.’s (2007) cornering law and assessed how corner angle and differences in path widths impacted cornering time. Participants navigated a virtual vehicle around corners of varying angles (45°, 90°, and 135°) and varying path widths. We found that increases in corner angle resulted in increased cornering times and a decreased probability of successful cornering. The findings from these experiments are applicable to contexts where an individual is tasked with remotely navigating around corners (e.g., video gaming, USAR, surveillance, military operations, training)

Investigating the Usability of a Vibrotactile Torso Display for Improving Simulated Teleoperation Obstacle Avoidance

While unmanned ground vehicle (UGV) teleoperation is advantageous in terms of adaptability and safety, it introduces challenges resulting from the operator\u27s poor perception of the remote environment. Previous literature on the ability of haptic feedback to augment visual displays indicates that UGV obstacle avoidance information may be more meaningfully communicated via vibrotactile torso systems. Presenting this information so that operators can accurately detect the proximity from walls and obstructions could result in a significant reduction in errors, ultimately improving task performance and increasing the usability of teleoperation. The goal of the current study was to determine the degree to which a vibrotactile torso belt could improve UGV teleoperation performance over video feed alone in a simulated environment. Sixty operators controlled a UGV using a simulated video feed, while half also utilized a vibrotactile belt. Results indicated that the vibrotactile display did not improve navigational performance or decrease subjective workload over video feed alone. Possible reasons for this and limitations are discussed

Aperture passability judgments in novice walker users: The impact of action scaling above and beyond body scaling

Many older adults who use assistive walking devices to improve stability and locomotion also report falls while using their device. The present study investigated how walking devices alter the perception-action system of the user. Specifically, the study assessed how walker users perceive their ability to pass through a doorway. One’s ability to pass through an aperture is constrained by their widest frontal dimension (body-scaling) and the dynamic properties of the individual in motion (action-scaling). In order to compare the unique impacts of body-scaling and action-scaling, novice users of a standard walker, wheeled walker, cane, or no device (control) made static and dynamic judgments of aperture passability while their lateral motion variability was recorded. Hierarchical Linear Modeling revealed that novice users successfully scaled their passability judgments to the width of the walker, and that the introduction of movement for the dynamic judgments resulted in more conservative perceptions of passability. Unexpectedly, motion variability was not a significant predictor of passability judgments, which suggests that the self-motion produced during dynamic judgments revealed additional environmental information (rather than intrinsic dynamic information) and allowed for the application of a margin of safety. Results of this study suggest that experience using the walking device is an important factor in ensuring new users understand their action capabilities and avoid injurious collisions and falls

SPATIAL PERCEPTION AND ROBOT OPERATION: THE RELATIONSHIP BETWEEN VISUAL SPATIAL ABILITY AND PERFORMANCE UNDER DIRECT LINE OF SIGHT AND TELEOPERATION

This dissertation investigated the relationship between the spatial perception abilities of operators and robot operation under direct-line-of-sight and teleoperation viewing conditions. This study was an effort to determine if spatial ability testing may be a useful tool in the selection of human-robot interaction (HRI) operators. Participants completed eight cognitive ability measures and operated one of four types of robots under tasks of low and high difficulty. Performance for each participant was tested during both direct-line-of-sight and teleoperation. These results provide additional evidence that spatial perception abilities are reliable predictors of direct-line-of-sight and teleoperation performance. Participants in this study with higher spatial abilities performed faster, with fewer errors, and less variability. In addition, participants with higher spatial abilities were more successful in the accumulation of points. Applications of these findings are discussed in terms of teleoperator selection tools and HRI training and design recommendations with a human-centered design approach

Effects of Interaction with an Immersive Virtual Environment on Near-field Distance Estimates

Distances are regularly underestimated in immersive virtual environments (IVEs) (Witmer & Kline, 1998; Loomis & Knapp, 2003). Few experiments, however, have examined the ability of calibration to overcome distortions of depth perception in IVEs. This experiment is designed to examine the effect of calibration via haptic and visual feedback on distance estimates in an IVE. Participants provided verbal and reaching distance estimates during three sessions; a baseline measure without feedback, a calibration session with visual and haptic feedback, and finally a post-calibration session without feedback. Feedback was shown to calibrate distance estimates within an IVE. Discussion focused on the possibility that costly solutions and research endeavors seeking to remedy the compression of distances may become less necessary if users are simply given the opportunity to use manual activity to calibrate to the IVE

Visually Guided Action for the Person-Plus-Object System: Generalizing the Optic Flow Equalization Control Law to Asymmetrical Bodies

Visually guided action in humans occurs in part through the use of control laws, which are dynamical equations in which optical information modulates an actor’s interaction with their environment. For example, humans locomote through the center of a corridor or through the center of two obstacles by equalizing the speed of optic flow across their left and right fields of view. This optic flow equalization control law relies on a crucial assumption: that the shape of the body relative to the eyes is laterally symmetrical. Humans engaging in tool use are often producing person-plus-object systems that are not laterally symmetrical, such as when they hold a tool, bag, or briefcase in one hand, or when they drive a vehicle. This dissertation tests a new generalized control law for centered steering that accounts for asymmetries produced by external tool use. Experiment 1 tested the efficacy of the generalized control law in a replication of Duchon & Warren (2002). Participants held an asymmetrical bar and centered themselves within a virtual moving hallway while the speed of the virtual walls were systematically changed. Experiment 2 assessed the application of the generalized control law to an aperture passability task, in which participants holding asymmetrical bars walked through real world apertures of various widths. The results of the current studies demonstrate that humans engaging with an asymmetrical tool can 1) perceive the asymmetry of a person-plus-object system, 2) use that information to modulate the use of optic flow equalization control laws for centered steering, and 3) functionally incorporate the asymmetrical tool into their perception-action system to successfully navigate their environment with a 97% success rate

Effect of avatars and viewpoints on performance in virtual world: efficiency vs. telepresence

An increasing number of our interactions are mediated through e-technologies. In order to enhance the human’s feeling of presence into these virtual environments, also known as telepresence, the individual is usually embodied into an avatar. The natural adaptation capabilities, underlain by the plasticity of the body schema, of the human being make a body ownership of the avatar possible, in which the user feels more like his/her virtual alter ego than himself/herself. However, this phenomenon only occurs under specific conditions. Two experiments are designed to study the human’s feeling and performance according to a scale of natural relationship between the participant and the avatar. In both experiments, the human-avatar interaction is carried out by a Natural User Interface (NUI) and the individual’s performance is assessed through a behavioural index, based on the concept of affordances, and a questionnaire of presence The first experiment shows that the feeling of telepresence and ownership seem to be greater when the avatar’s kinematics and proportions are close to those of the user. However, the efficiency to complete the task is higher for a more mechanical and stereotypical avatar. The second experiment shows that the manipulation of the viewpoint induces a similar difference across the sessions. Results are discussed in terms of the neurobehavioral processes underlying performance in virtual worlds, which seem to be based on ownership when the virtual artefact ensures a preservation of sensorimotor contingencies, and simple geometrical mapping when the conditions become more artificial