Chapter 12 – Navigation

Publisher Summary One of the problems with mobile robots is to know where they are. This chapter explains some of the problems and offers some solutions. Magnetic compass is one of the most useful ones for navigation. It is possible to program a complex course for the robot and expect to have it followed with reasonable accuracy. The only problem might be that local magnetic fields will affect the precision of the inbuilt compass. Avoid running the robot on a surface supported by a cast-iron framework. Further, edge follower gives robot a rather strange gait, but it gets there eventually and is very economical on programming space. This routine is controlled by a switch block that is programmed to switch at a preset light level. Below 50, the robot is spun to the right. If the level is above 50, the robot is spun to the left. After spinning left or right, the robot runs forward a short distance and then the routine is repeated. As a result of these opposing responses, the robot follows the right-hand edge of the line. It can also follow around the edge of a much larger area. Swapping the spinning blocks makes the robot follow along the left hand side of the line. Alternatively, it follows the left hand edge of a white line drawn on a dark background.