Development of a Laser Range Sensor for a Mobile Robot

External sensors which can detect environmental information are important for a mobile robot to recognize its surroundings and location. Among external sensors, range sensors are fundamental because they can directly detect the free space in which the mobile robot can move without colliding with the surrounding objects. A laser range sensor provides good spatial resolution, and it is expected to detect characteristic parts of the environment used as landmarks for recognizing robot position. This paper presents the construction of a laser range sensor system which can be implemented in a small mobile robot. The system consists of several components including laser diode, CCD camera, and mark detection hardware. Based on triangulation method, the system can detect the distance to the object's surface on which the beam spot is directed. In order to detect a landmark, such as a wall edge, the sensor system is mounted on a rotary table. By horizontally scanning, the sensor can detect wall edges with an accuracy of approximately 5mm and an orientation accuracy of approximately 1 degree within 3m. This system has been installed in an indoor mobile robot and is used for autonomous navigation control along corridors. © 1991, Fuji Technology Press. All rights reserved.