Fusion of direction sensing RFID and sonar for mobile robot docking

Finding and moving to a target is a key element toward enhancing functionality and autonomy of mobile robots in a variety of applications. For the purpose, the location sensing radio frequency identification (RFID) system has been proposed by the authors. Real time tracking of the target transponder became available by employing the dual-directional antenna. However, since the system depended on the accuracy of the estimation for direction of arrival (DOA) of transponder signals, the systempsilas performance may deteriorate in electromagnetically noisy or cluttered environments. In this paper, the features of the system are improved to accommodate such situations. The error correction algorithm is incorporated to provide a robust estimation of DOA, and sonar data are fused to characterize the environment. To verify the validity of the proposed system, we perform simulations and experiments of mobile robot docking in a real environment populated with stationary and movable obstacles.