Transfer movement control of mobile robot using two circular arcs

Abstract

Abstract This report describes a method of controlling a robot vehicle to move smoothly on a visually natural path. In this method, discrete points which the robot passes, and directions toward which it moves, are provided on an arbitrary coordinate system given in a movement environment. The continuous curve required for the robot vehicle to move is represented by a total curvature function obtained by accumulating curvatures of curves. Using the function, an algorithm is obtained for generating the robot moving path from interpolation of two circular arcs containing both the lengths and curvatures of the two circular arcs. The position at which the robot is passing and the direction toward which it is moving are measured based on the principle of the triangle survey for three reference patterns set in the movement environment. This is possible by measuring the directions from the current position to the patterns with an ITV camera. This method produces a directional error caused by the roughness of the step angle (0.9) of the stepping motor driving the ITV camera. This paper proposes a method of compensating the directional error by taking into account the number of pixels in pictures taken per step. This system has the averaged position measurement error of 0.8 percent against the coordinate system including the reference patterns. From the result, it is proved that a comparatively simple method enables the moving path of a robot to be controlled accurately.