The University of Edinburgh -
Division of Informatics
Forrest Hill & 80 South Bridge

PhD Thesis #9225

Title:Analysis and Synthesis in the Design of Locomotor and Spatial Competences for a Multisensory Mobile Robot
Date: 1992
Abstract:This dissertation reports on experiments in the design of a free-ranging robotic vehicle with locomotor and spatial skills. These two skills are suggested to be fundamental to any general mobile agent. No attempt has been made to incorporate manipulation, and motivational issues are not treated (the system's objectives are specified by a human). Two schools of thought with regard to robot design prevail: they are the representation-based or analytic, and representation-free of synthetic schools. These guiding philosophies are compared and contrasted in terms of their approaches to locomotion and localisation. In the course of this work, it has been found that the smoothness of a mobile robot's locomotion benefits from adjusting its speed to the density of obstacles it is encountering. A reactive, synthetic-type procedure for achieving this is offered, based on the frequency at which obstacle detection interrupts the robot's navigational system. However, it will be shown that a predictive, representation-based approach is more efficient. On the other hand, it will emerge that a very limited representation of the robot's operating environment and sensing systems is sufficient to allow the robot to localise accurately anywhere within its operating space, based only on the goodness of match between mapped and currently sensed data. The scheme treats the infrared, sonic, and ultrasonic sensors of an autonomous mobile robot as devices which partition its operating space qualitatively. It will be shown that the infrared and ultrasonic systems combined lead to position estimates accurate to within 10 cm of where the robot actually is, on average. These systems are found to be superior to the sonic system, surprisingly, because they have distinct regions within which they do not work: it is better to have accurate sensors with dead zones than inaccurate ones which can be used anywhere. Since it is not obvious which aspects of r

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