Research And Implementation Of 3D Positioning System Based On UWB

With the development of science and technology,the requirements of barn for flat grain robot have changed from traditional grain transportation systems to more advanced intelligent robot systems.The positioning system is the intelligent embodiment of grain transportation robot,a set of positioning system suitable for barn environment could greatly improve the work accuracy of grain transporting robot.Outdoor positioning technology is not suitable for indoor because of the Shielding of building facades.Compared with various indoor positioning technologies,Ultra Wide Band(UWB)positioning technology has the advantages of strong penetration,low power consumption,strong anti-multipath performance and high positioning accuracy,Therefore,UWB positioning technology is more suitable for the granary and other more complex working environment,and this these proposed a set of 3D positioning system based on UWB for the flat grain robot.The main work of this paper has the following several aspects.This thesis designed a three-dimensional positioning system based on UWB for flat grain robot.first,in order to save space resources,this thesis chosen the L-shape three base station configuration model;Second,in order to get distance information,the ranging method of DS-TWR was selected.The least square method and spatial projection method was selected to complete the estimated coordinates of the measured object.Experiments show that the three-dimensional positioning algorithm of the three base stations is effective,but the dynamic positioning accuracy has low performance.The positioning trajectory after Kalman filtering was obviously smooth,and the positioning error was further smaller.In order to obtain the attitude of the measured target,the positioning label coordination and positioning method was designed.Aiming at the slow update frequency of the UWB positioning system,this thesis designed the combined positioning system of IMU inertial navigation system.It makes full use of the features of inertial positioning system and UWB positioning system could potentially complement one another,inertial positioning could be continuously processed for UWB positioning information,compensation for the problem of slow refresh frequency of UWB module,In the dynamic process of continuous optimization of UWB.This thesis designed attitude solution correction algorithm based on IMU.The experiment results show that this combined positioning method broke the limitation of motion speed,positioning accuracy had been improved,the attitude correction algorithm proposed in this thesis effectively improved the attitude settlement accuracy.In view of the positioning method,this thesis set up the hardware test platform and software platform of the indoor positioning system,set up the system test environment in the laboratory,completed the experimental verification of the positioning system,and the positioning effect of the upper machine.In the case of NLOS(Non-Light of Sight,NLOS),the dynamic positioning accuracy error of this positioning system is about 10cm,the attitude solution error is within,and the positioning effect met the needs of the flat grain robot.