Accurate calibration of systematic errors for car-like mobile robots using experimental orientation errors

Abstract

One of the essential technologies for autonomous navigation is localization. Localization is important because accurate pose estimation is required for path planning and motion control. In order to improve localization accuracy, a relative positioning method on the basis of accurate odometry is necessary. Odometry calibration methods for two wheel differential drive robots have been researched for many years. However, it is difficult to find odometry calibration methods for car-like mobile robots. In this paper, an accurate calibration method for car-like mobile robots is proposed. Experimentally measured orientation errors were used to improve the accuracy of the calibration method. There are two contributions in this paper. The first is the significant reduction of calibration errors by the use of accurate calibration equation. In the previous research, calibration equation required approximations. However, there is no approximation error in the proposed equation owing to the use of orientation errors, not positional errors. The second is the experimental convenience. The orientations can be easily measured by onboard inertial sensors. Therefore, calibration experiments can be easily carried out in both indoor and outdoor environments. The presented experimental results show that resultant performance of the proposed scheme is superior to the results of the previous research.