| With the continuous development of the robot industry,more and more mobile robots are applied to indoor services.How to realize the autonomous movement of indoor mobile robots has become a hot and difficult point in current research and realizing high-precision real-time positioning is more important.Among the many indoor wireless positioning technologies,Ultra Wide Band(UWB)positioning technology can achieve centimeter-level positioning accuracy under the line of sight(LOS)environment without accumulated positioning error,which is suitable for achieving high Accurate real-time positioning,but the positioning accuracy in the non-line-of-sight(NLOS)environment will significantly reduce.Dead reckoning(DR)positioning technology provides accurate short-term positioning without NLOS errors,but is dragged down by cumulative errors.Therefore,in order to achieve high-precision real-time localization of indoor mobile robots,this paper proposes a UWB/DR combined localization method based on Unscented Kalman Filter(UKF).Based on the analysis of the mobile robot motion actuator,a two-wheel differential wheeled motion model was selected and analyzed kinematically;combined with the DR positioning principle and kinematic analysis,the two-wheel differential mobile robot DR positioning formula was derived,further An optimized DR positioning formula based on arc accumulation was proposed,and the optimization effect of this method was verified by MATLAB simulationBased on the analysis of the principles,advantages and disadvantages of TOA,TDOA,AOA,and RSSI-based positioning methods in UWB positioning,the UWB positioning formulas based on TOA and least squares methods are derived;The NLOS error,clock inconsistency error and antenna delay error in UWB positioning are analyzed and corresponding optimization methods to reduce errors are proposedThe specific implementation of UKF is analyzed and the state prediction function and observation function of UKF are deduced from the DR positioning formula and UWB positioning formula.Due to the problem of weakening the UKF filtering effect in the NLOS environment,an environment-adaptive UWB/DR combined positioning method based on the UKF is proposed.This method uses the 3? principle of Gaussian distribution to detect NLOS errors and correct the observation noise in real time,thereby optimizing the UWB/DR combined positioning method based on the UKF;the optimization effect of the proposed method is verified by MATLAB simulation.An experimental platform consisting of a mobile robot prototype,a UWB ranging system,a host computer system,and a host computer system was built,and a prototype positioning experiment was performed in a covered indoor environment.The experimental results show that the environment-adaptive UWB/DR combined positioning method based on the UKF has a positioning accuracy of 10 cm in the LOS environment,and it can effectively suppress non-line-of-sight positioning errors in the NLOS environment,and the positioning accuracy is comparable to the accuracy in the LOS environment,and improving positioning performance and robustness of the positioning system. |
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