Increasing localization accuracies by hybrid maps and scan matching

The technique of simultaneous localization and mapping has received much attention recently in mobile robotics. When map is being built, robot memorizes environmental information on the plane of grid or topology. Several approaches about this research have been presented so far, but most of them use mapping technique as either grid-based map or topology-based map. This paper proposes some algorithms integrating grid and topology map and its performance is faster and more stable. The proposed scheme uses an occupancy grid map in representing the environment and then formulate topological information in path finding by A* algorithm. The localization process and the dynamic obstacle avoidance can be accomplished by topological information on grid map. On simulator mapping process is shown and the shortest path is decided on grid based map. Then topological information such as direction, distance is calculated on simulator program then transmitted to robot hardware devices. Three ultrasonic sensors and electronic compass are implemented on our mobile robot and two DC geared motor wheels are individually controlled by PD control method. Simulations and experimental results show the performance and efficiency of the proposed scheme.