Development of a Smart Laser Range Finder for an Autonomous Service Robot

In this paper we propose an advanced modularization of robotic systems by unification of the connections between different devices. The robot system consists of smart sensors, multiple computers for different control tasks and several actuators that are connected by standard network technologies. The paper will discuss the reasons for a modularized system design and a novel smart sensor will be presented to verify the assumptions made. The smart sensor is an embedded device for connecting laser range finders to a mobile service robot controlled by an on-board industrial PC. On the service robot, the range measurements are used for different parallel tasks like collision prevention, self-localization or people tracking. The laser range finders are equipped with a 500 kBd RS-422 serial interface. It is difficult to integrate them into an existing system because most systems do not provide a serial interface capable of operating at the unusual baudrate of 500 kBd. Therefore a special purpose RS422-to-Ethernet adapter based on a Rabbit-3000-CPU was designed. This unit receives the measurement data from the range finders and sends UDP-packets containing the data over Ethernet. Additionally, automatic control of the laser range finders and pre-processing of the measurement data is done within the Rabbit-3000-CPU. The smart sensor is not only usable on a service robot, it can be used with any device providing an Ethernet interface.