Implementation of on-board position estimation for a mobile robot - EKF based odometry and laser reflector landmarks detection -

The usual method for position estimation of a wheeled mobile robot is odometry. However, it has the problem of gradual error accumulation when the robot moves. To solve this problem, we place several reflectors sparsely in the robot's work-space as landmarks, so that the robot can correct its estimated position when detecting the landmark. The new estimated position of the robot is calculated by the Maximum Likelihood Estimation (MLE) by both the position information estimated by odometry and the Reflector Detecting Sensor system (ReDS) using the laser beam. ReDS, which we developed can detect the reflector at most 3 meters away from the robot in the indoor environment. Practical experiments show that the estimated position obtained by this system is precise enough to be useful.