Design And Research Of Heavy-duty AGV Positioning System Based On UWB

Heavy-duty AGV has always attracted attention due to their advantages of heavy load bearing,flexible movement and high reliability.The key to researching heavy-duty AGV technology lies in the research of positioning technology.Ultra Wide Band(UWB)wireless positioning technology has become the hot spot and first choice for wireless positioning technology due to its low system complexity,strong signal anti-multipath capability and high positioning accuracy.However,in a complex application environment,the Non-Line of Sight(NLOS)error has a great influence on the UWB positioning accuracy.Therefore,this paper proposes an N-KOTA(NLOS-Kalman-Optimized Trilateration Algorithm)which is resistant to NLOS error.Location Algorithm.Finally,a set of UWB wireless positioning system is designed,and the performance test of the positioning system is completed through the self-built heavy-duty AGV.The main work of this paper is as follows.1.From the theoretical point of view,the definition,characteristics and positioning principle of UWB technology are described.Several common wireless positioning methods are introduced,and the positioning method based on signal time of flight(TOF)is selected.Through principle derivation and error analysis,several TOF-based ranging algorithms are compared,and the Alt DS-TWR(Alternative Double-sided Two-way Ranging)algorithm with low difficulty in implementation and high ranging accuracy is selected as the ranging algorithm in this paper.And summarizes the common positioning accuracy influencing factors and positioning performance metrics.2.In order to solve the problem of low positioning accuracy of UWB in non-line-of-sight environment,an N-KOTA positioning algorithm against NLOS error is proposed.Firstly,the NLOS error model is established,and the NLOS ranging data is reconstructed by Kalman filter through NLOS error identification,and then the optimized Trilateration Algorithm(OTA)is introduced to estimate the final target positioning point.The dynamic positioning simulation results show that the RMSE value of the N-KOTA positioning algorithm in the NLOS environment is concentrated at 12 cm,which has a high accuracy.3.Design a set of UWB positioning system with three base stations and one tag.The system includes hardware circuit design,underlying software design and upper computer software design.The hardware of the UWB positioning system adopts a tag-base station integrated design and is distinguished by a DIP switch.The host computer software can realize functions such as data analysis,positioning calculation and positioning visualization.4.Apply the proposed N-KOTA positioning algorithm to the UWB positioning system designed in this paper,and perform dynamic and static positioning experiments on the real position of the heavy-loaded AGV in indoor LOS and NLOS environments.In the LOS environment,the experimental results show that the static positioning error of the system is 8.38cm;in the NLOS environment,the experimental results show that the static positioning error of the system is 13.98 cm,and the root mean square error of the dynamic positioning results is 15.41 cm.Therefore,the N-KOTA positioning algorithm proposed in this paper can effectively suppress the NLOS error,greatly improve the system positioning accuracy and overall stability,and can meet the system design requirements.