Calce, A., Mojiri Forooshani, P, Speers, A., Watters, K., Young, T. and Jenkin, M. Autonomous aquatic agents. Proc. ICAART 2013, Barcelona, Spain, February 2013.
Constructing a collection of autonomous agents requires the development of appropriate experimental hardware platforms. Here we describe the process of re-purposing inexpensive radio-controlled (RC) electric motorboat as autonomous surface craft. Standard electronics components are used to interface with the RC boat electronics, and the vessels are augmented with GPS, vision, and a tilt-compensated compass to provide the necessary onboard sensing capabilities to enable point-to-point and target-based control of the vehicle. A ROS-based control and sensing infrastructure is used to operate the vehicles on-board while 802.11n communication provides communication off-board. Vessels have been operated successfully in both the pool and ocean environment.A poster of the paper presented at the conference can be found here.
Yang, J., Codd-Downey, R., Dymond, P., Xu, J. and Jenkin, M. Planning practical paths for tentacle robots. Proc. ICAART 2013, Barcelona, Spain, February 2013.
Robots with many degrees of freedom with one fixed end are known as tentacle robots due to their similarity to the tentacles found on squid and octopus. Tentacle robots offer advantages over traditional robots in many scenarios due to their enhanced flexibility and reachability. Planning practical paths for these devices is chal- lenging due to their high degrees of freedom (DOFs). Sampling-based path planners are a commonly used approach for high DOF planning problems but the solutions found using such planners are often not practical in that they do not take into account soft application-specific constraints during the planning process. This paper describes a general sample adjustment method for tentacle robots, which adjusts the randomly generated nodes within their local neighborhood to satisfy soft constraints required by the problem. The approach is demonstrated on a planar tentacle robot composed of ten Robotis Dynamixel AX-12 servos.
Barnett-Cowan, M., Jenkin, H. L., Dyde, R. T., Jenkin, M. R. and Harris, L. R. Asymmetrical representation of body orientation. J. of Vision, 13: 1-11.
The perceived orientation of objects, gravity, and the body are biased to the left. Whether this leftward bias is attributable to biases in sensing or processing vestibular, visual, and body sense cues has never been assessed directly. The orientation in which characters are most easily recognized-the perceived upright (PU)-can be well predicted from a weighted vector sum of these sensory cues. A simple form of this model assumes that the directions of the contributing inputs are coded accurately and as a consequence participants tilted left- or right-side-down relative to gravity should exhibit mirror symmetric patterns of responses. If a left/right asymmetry were present then varying these sensory cues could be used to assess in which sensory modality or modalities a PU bias may have arisen. Participants completed the Oriented Character Recognition Test (OCHART) while manipulating body posture and visual orientation cues relative to gravity. The response patterns showed systematic differences depending on which side they were tilted. An asymmetry of the PU was found to be best modeled by adding a leftward bias of 5.6 degrees to the perceived orientation of the body relative to its actual orientation relative to the head. The asymmetry in the effect of body orientation is reminiscent of the body-defined left-leaning asymmetry in the perceived direction of light coming from above and reports that people tend to adopt a right-leaning posture.A locally cached version can be found here.
Speers, A., Forooshani, P., Dicke, M. and Jenkin, M. Lightweight tablet devices for command and control of ROS-enabled robots. Proc. 2013 International Conference on Advanced Robotics (ICAR). Montevideo, Uruguay, 2013.
Effective interaction with autonomous devices is a complex problem as the devices themselves are mobile. For the vast majority of devices operating over an extended range a fixed operator or oversight position is inappropriate and mobile oversight becomes essential. Although walking in the vicinity of an autonomous robot with a networked laptop may be appropriate for some environments, such an approach becomes increasingly cumbersome as the robot moves out into the field where weather and other operational concerns are factors. Here we examine the use of lightweight tablet computers as a generic interface to autonomous systems. We demonstrate how ROS-enabled computers can be controlled using Android tablets using standard software toolkits. Tools have been developed for the automatic conversion between ROS messages and the corresponding user interface elements on the tablet and a collection of robot-centric user interface elements have been developed to assist in developing systems for different robot sensors and platforms. Systems are demonstrated for unmanned underwater, surface, flying and rolling ground contact vehicles.
