Teather, R. T., Natapov, D. and Jenkin, M., Evaluating haptic feedback in virtual environments using ISO 9241-9. Proc. IEEE VR 2010, Waltham, MA.
The ISO 9241 Part 9 standard pointing task is used to evaluate passive haptic feedback in target selection in a virtual environment (VE). Participants performed a tapping task using a tracked stylus in a CAVE both with, and without passive haptic feedback provided by a plastic panel co-located with the targets. Pointing throughput (but not speed nor accuracy alone) was significantly higher with haptic feedback than without it, confirming previous results using an alternative experimental paradigm.
Harris, L. R., Jenkin, M. R. M., Jenkin, H. L. M., Dyde, R. T. and Oman, C. M. Where's the floor? Seeing and Perceiving, 23: 81-88, 2010.
Visual and balance cues concerning the relative orientation of ourselves and our environment combine to direct our steps to select a secure footing. How are visual cues used to select the best support surface? Here we show that, when expose to tilted, rectangular rooms of various aspect ratios, subject do not necessaily chose the surface whose normal is oriented closes to the gravity-defined vertical. Rather their decision is also strongly biased by the visual area subtended by each candidate surface.
Yang, J, Dymond, P. and Jenkin, M. Exploiting hierarchical probabilistic motion planning for robot reachable workspace estimation. Lecture Notes in Electrical Engineering (LNEE)85: 229-242, Springer-Verlag, 2010.
Given an environment and a robot, how much of the environment is reachable or accessible to the robot? This fundamental problem in robotics is know as reachable workspace estimation and is closely related to the problem of determining possible kinematic motions of a robot. For mobile kinematic structures with high degrees of freedom (DOFs) in cluttered environments, the motion planning problem is known to be NP-hard. Given the intractability of the problem, we present an efficient probabilistic method for workspace estimation based on the use of a hierachical strategy and a probabilistic motion planner. Th probabilisitc motion planner is used to identify reachable portions of the workspace but rather than treating each DOF equally, a hierachical representation is used to maximize the volume of the robot's workspace that is identified as reachable for each problem of the environment. Experiments with a simulated mobile manipulator demonstrate that the hierachical approach is an effective alternative to the use of an estimation process based on the use of a traditional probabilistic planner.
Mantegh, I., Jenkin, M. R. M., and Goldenberg, A. A. Path planning for autonomous mobile robots using the boundary integral equation method. Journal of Intelligent and Robotic Systems, 59: 2010.
Path planning is a fundamental problem in mobile robotics. The objective of path planning is to find a sequence of states that carries a robot from some start state tot eh goawl while avoiding obstacles. This paper focuses on point-to-point path planning, ie., developing a path between given points in a known environment with obstacles. A novel environment representation method is introduced which utilizes the Boundary Integral Equation (BIE) method to map the enviornment into a continuous Harmonic potential fields. Different mappings and mechanisms for utilizing these mappings for path planning are developed, and a collection of path planning algorithms are described which exploit the properties of Harmoci fields and the computational efficiency of the BIE method.
Jenkin, M., Verzijlenberg, B. and Hogue, A. Progress towards underwater 3D scene recovery. Proc. C3S2E, Montreal, PQ, May, 2010.
The underwater environment presents many challenges for robotic systems and sensors. Not only is it difficult to determine appropriate locomotive and control strategies, sensing underwater is plagued by highly variable lighting, dynamic objects, and suspended particulate matter. Despite these challenges the aquatic environment presents many real and practical applications for autonomous robots. Fundametnally, these tasks require knolwedge of the 3D environment, the robot's loation within the environment, and reactive vehicle control. In this paper we describe solutions to the problem of providing effective control of underwater structures. Two specific components of the research are described here: (i) a 3D stereo-vision sensor that inegrates stereo vision imagery with inertial measurements, and (ii) a tablet-based control interface that can be used to control the process of data collection.
Dyde, R., Zacher, J., Jenkin, M., Jenkin, H. and Harris, L. R., Perceptual orientation judgements in astronauts: pref-flight measures. Proc. VSS, Naples, FL, 2010
Introduction: Bodies in the Space Environment (BISE) is a Canadian Space Agency sponsored experiment currently running onboard the International Space Station. The project examines the effect of long-term exposure to microgravity on perceived object orientation. Methods: Thirteen astronauts were tested using the Oriented Character Recognition Test (OCHART) as part of the pre-flight data collection process. OCHART measures the orientation at which a letter probe is "perceptually upright" (PU) (Dyde et al. 2006 Exp. Brain Res. 173: 612). OCHART was performed while upright and lying right-side-down (rsd). By varying the background orientation and the orientation of the subjects the relative contribution of vision, gravity and the body can be determined. Data from 49 undergraduate students were collected for comparison. Students' data variance was computed and a second pool of 24 student subjects was constructed to match variance in the astronaut subject pool. Results: When in an upright posture the direction of PU was more influenced by a tilted visual background for the complete student group compared to astronauts. Astronauts' PUs had significantly smaller variances than those of the complete student group. Comparing the astronauts with a group of 24 students (matched for variance) showed that there was no difference in the influence of the tilted background on PU between these two groups. When these two groups' data was compared in the rsd posture, the direction of PU was reliably closer to the axis of gravity (and further away from the body centre-line) for the students compared to astronauts. Discussion: Initial data suggest that astronauts rely less on the axis of gravity when performing an orientation measure compared to a student-group matched for variance. Experiments are ongoing with a subject pool age-matched to the astronaut group.
Wang, H., Jenkin, M., and Dymond, P., Using a string to map the world. Proc. IEEE/RSJ Int. Conf. on Robotics and Intelligent Systems (IROS), Taipei, Taiwan, 2010.
Literature and folklore is rife with a range of oracles that have been used by explorers to explore unknown environments. But how effective are these various oracles? This paper considers the power of string and string-like oracles to map an unknown embedded topological environment. We demonstrate that for undirected graphs, even very short strings can be used to explore an unknown environment but that significant performance improvements can be found when longer strings are available.
Verzijlenberg, B. and Jenkin, M. Swimming with robots: human robot communication at depth. Proc. IEEE/RSJ Int. Conf. on Robotics and Intelligent Systems (IROS), Taipei, Taiwan, 2010 .
Human-robot communication is a complex problem even in the terrestrial domain. Failure to properly communicate instructions to a robot and receive appropriatae feecback can at the very least hamper the ability of the robot to perform its task, and at worst prevent the task from being completed. The problem of providing effective communication between a robot and its operator becomes even more complex underwater. Many communication channels available in the terrestrial domain become unavailable, and communication between team members and task oversight become even more complex. This paper describes initial experiments with the AQUATablet - a robot interactino device designed to be operated by a diver tethered to, or in visual communication with, an underwater robot. The basic requirements of the device are described along with design considerations and results of initial experiments with the device conducted in the pool and in the open ocean.An epub version of the paper is also available.
Dudek, G. and Jenkin, M., Computational Principles of Mobile Robotics, Cambridge University Press, 2nd Edition, 2010.
This is a textbook for advaned undergraduate and graduate students in the field of mobile robotics. Emphasising computaiton and algorithms, the authors address a range of strategies for enabling robots to perform tasks that involve motion and behavior. The book is divided into three major sections: ocomotion, sensing and reasoning. It concentrates on wheeled and legged mobile robots, but discusses a variety of other propulsion systems. Kinematic models are developed for many of the more common locomotive strategies. It presents algorithms for both visual and nonvisual sensor technologies, including sonar, vision and laser scanners. In the section on reasoning, the authors offer a thorough examination of planning and the issues related to spatial representaiton. They emphasize the problems of navigation, pose estimation, and autonomous exploration. The book is a comprehensive treatment of the field, offering a discussino of state-of-the art methods with illustrations of key technologies.
Codd-Downey, R., Jenkin, M., Ansell, M., Ng, H.-K., and Jasiobedzki, P. Simulating the C2SM 'fast' robot, Proc. SIMPAR 2010, Darmstadt.
A critical problem in the deployment of commercial teleoperated robots is the development of effective training tools and methodologies. This apper describes our approach to the problem of providing such training to robot operators tasked to contaminated environments. The Vanguard MK2 and C2SMFast Sensor Simulator - a rivtual reality based trainig system - provides an accurate simulation of the C2SM Crime Scene Modeler, an autonomous robotic system developed for the investigation of contaminated crime scenes. The training system provides a simulation of the underlying robotic platofrm and the C2SMFast sensor suite, and allows training on the system without physically deployting the robot or CBRNE contaminants. Here we describe the basic structure of the simulator and the software components that were used to construct it.
Zikovitz, Daniel, Keith Niall, Laurence Harris, and Michael Jenkin. “Simulated Day and Night Effects on Perceived Motion in an Aircraft Taxiing Simulator.” In Modeling Simulation and Optimization. Edited by Shkelzen Cakaj. Intechopen, 2010.
Flight simulation often depends on both visual simulation and movement by a motion base. The present study asks if tilt is equivalently perceived as linear translation, and if so, whether other information such as simulated day or night conditions may affect accuracy. We examine the perception of self-motion in non-pilots during passive simulated airplane taxiing along a straight runway. Providing physical motion cueing by a motion platform, simulation scenarios were presented at a constant physical or visual acceleration of either 0.4 m/s2 or 1.6 m/s2 (simulated using tilt). Nine subjects indicated the moment when they perceived that they had travelled through distances between 10 to 90 m under either day or night-time display conditions. Their estimates were made either with or without tilt (to simulate linear acceleration). We present results as a ratio of response distance (response distance) to stimulus distance (stimulus distance). Subjects’ motion estimates under tilt con- ditions do not significantly differ from under vision-only conditions. We found an interac- tion of tilt and illumination conditions, particularly for targets greater than 30 m. The ratio of response distance to stimulus distance significantly increases in the dark (1.1 vs. 0.85), at higher accelerations (1.01 for 1.6 m/s2 vs. 0.95 for 0.4 m/s2) and, during daytime illumina- tion, in the presence of a physical-motion cue (0.92 vs. 0.78). Conditions affecting the magnitude of perceived self-motion include: illumination, magnitude of the simulated acceleration, presence of physical tilt during daytime illumination. This study shows that passive humans can be expected to make significant, predictable errors in judging taxiing distances under specific simulation conditions. Questions for further research include: if similar effects occur in pilots as in non-pilots, if such effects also occur in real taxiing scenarios. The results obtained here may help to counter perceptual errors, as the results become part of the knowledge on which appropriate cueing schemes can be based.
