A method of autonomous locomotion for mobile robots

Abstract

_A navigation method is presented which enables a mobile robot to perform autonomous locomotion. The feasibility of this method was demonstrated using experimental hardware_a prototype robot with ultrasonic sensors. This method uses objects of simple shape, such as poles and flat surfaces of walls selected from the environment, as landmarks and a map which indicates the relations of these landmarks. The robot moves from a given point to another along a designated path using its sensors. At each point it measures the positions of the objects selected as landmarks and corrects its path. The following basic problems encountered in realizing this method are discussed: (a) path design connecting two points in the environment; (b) the control ofthe robot's path; (c) measurement ofthe objects' positions using an ultrasonic sensor; and (d) correction of error from the designated path. To navigate a mobile robot it is necessary to be able to control it so that a specified path is followed accurately. Since absolute positional information is not available, the mobile robot must obtain accurate positional data from its surroundings. The method uses natural objects to gain such information. Its advantages include: (a) reduction in the investment of equipment for the supply of positional data; and (b) simplification of the object detection problem by giving information on the objects.