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This thesis is concerned with spatial aspects of perception and action in a simple robot. To this end, the problem of designing a robot-controller for a robot in a simulated robot-environment system is considered. The environment is a two-dimensional tabletop with movable polygonal shapes on it. The robot has an eye which 'saes' an area of the tabletop centred on itself, with a resolution which decreases from the centre to the periphery. Algorithms are presented for simulating the motion and collision of two dimensional shapes in this environment. These algorithms use representations of shape both as a sequence, of boundary points and as a region in a digital image. A method is outlined for constructing and updating the world model of the robot as new visual input is received from the eye. It is proposed that, in the world model, the spatial problems of path-finding and object-moving be based on algorithms that find the skeleton of the shape of empty space and of the shape of the moved object. A new iterative algorithm for finding the skeleton, with the property that the skeleton of a connected shape is connected, is presented. This is applied to path-finding and simple object-moving problems. Finally, directions for future work, are outlined. / Science, Faculty of / Computer Science, Department of / Graduate

A new family of automata, one-way multihead marker automata, is introduced. Intuitively these devices consist of one or more read heads travelling in a single direction on a bounded tape and a finite fixed pool of markers which may be deposited on the tape, sensed, and later removed. The major results obtained are: (i) A one-way n-head k-marker automaton with distinguished markers (each marker is recognizably distinct) may be simulated by a one-way n-head (k+1)-marker automaton with uniform markers (one marker cannot be told from another); (ii) Minor restrictions in pebble use and head movement do not significantly affect the recognition power of these devices, consequently it is possible to obtain normal forms for devices with either distinguished or uniform markers; (iii) If p(x) is a polynomial with positive integer coefficients of degree k>0 then the language {0P(n) |n Ɵ {0,1,2,...}} is recognized by a deterministic s.one-way k-head (k-1)-marker automaton; (iv) There exists a class of one-letter languages, characterized by finite linear difference equations, which are recognized by a deterministic one-way n-head 2-marker automaton. Members of this class include the fibonacci numbers and all languages {0(kn) |n Ɵ {0,1,2,...}}, k a fixed natural number. This class is of particular interest since it contains languages not generable by any polynomial, proving that a complete characterization of the one-letter languages recognized by one-way multihead marker automata can not rest upon the polynomial languages alone. / Science, Faculty of / Computer Science, Department of / Graduate

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In today's high-tech industrialized world, we are always looking for faster, and more reliable ways to produce goods. Robotics offers us a possible replacement for the human worker, but can a robot reliably perform the same tasks as a human arm, for example?The complex problem of teaching a robot to move it's hand in some well defined path can be broken down into a variety of algorithms. These path control algorithms generally compute some path description equation, which is used to generate path points either in terms of the Cartesian coordinates of the robot's work cell or the robot's joint variables. Common functions used in the path generation process include cubic spline functions and linear functions.This research project tests a variety of algorithms on a relatively simple robot in order to perform the task of drawing shapes (lines, squares, circles) on planes (horizontal and vertical) in the workcell. By studying the paths drawn we can determine the effect of each algorithm on the path control process, as well as the effect of plane positioning, robot structure, and the robot's controller. / Department of Computer Science