Collision Avoidance System

Fig. 1: Laser-Range-Finder

The collision avoidance system is based on detection of the opponent robots by laser-range-finders (LRF) mounted on top of the stationary beacons. A plain cylinder is put on the mobile beacon supports, reflecting the rays of the laser-class1 device. The LRF converts the received optical signals into a digital information of distance and angle. If more than one ray hits an object, even the size can be estimated roughly. The distance/angle-information of all detected mobile beacon cylinders within the dimensions of the table gets transformed to Cartesian coordinates by software and sent to our own robots by XBee RF modules. In this way the position of the opponent robots is known during the whole match, so collisions can be avoided.

In contrary to last year the processing of the LRF data is performed by a STM32F407 microcontroller instead of a windows-based micro-PC. This allows the integration of all necessary electronics (LRF, microcontroller, battery and touch screen) within a single stationary beacon housing. This enables us to use 3 such LRF-beacons at once for additional precision of the coordinates (about 10-20mm). Moreover it allows a much easier and more reliable operation of the beacons.