Cooperative localization of multiple robots with Constraint Propagation technique

We propose a new cooperative localization method based on CP (constraint propagation) technique for multiple mobile robots sharing position information with each others. In case of conventional probabilistic methods such as EKF, they give the most probable estimation rather than guarantee any deterministic values or boundary for true position of the robots. To comply with such cases as at least boundary of robot position should be guaranteed, we propose a CP-based method that can handle the cases and gives a boundary containing true robot position value. To be specific, we apply the constraint propagation technique to localizing a set of mobile robots equipped with wheel encoders, gyro meters, and GPS receivers. Fusing the data and applying CP, we can get improved accuracy for localizing the robots. Also, by introducing the correlation between GPS data in common workspace to the sensor fusion framework, we further improve the localization accuracy for multiple robot cases. Several simulation results showing that the proposed method improves localization performance considerably compared to conventional methods will be shown.