Study And Design On AGV Positioning System Based On UWB

Positioning technology is the core of AGV(Automated Guided Vehicle)application technology,and is the key technology of AGV to achieve full time independent work.Only if they know the location of their own,the location of the material and obstacles,AGV can carry out safe and effective autonomous movement.At present,AGV uses magnetic stripe guidance,laser guidance and other technologies to locate,the requirements of the environment configuration is high,so it can't adapt to the complex and changeable logistics warehouse production environment.On the other side,UWB(Ultra-Wideband)as a kind of wireless communication technology revolution,in addition to accurate positioning,high-speed data transmission,but also has no carrier,anti-multipath interference characteristics,has received extensive attention of scholars at home and abroad.In recent years,UWB technology has become increasingly popular,the cost of its related equipment is also getting cheaper.Under this background,we studied and designed the AGV positioning system based on UWB in this paper.This system not only can meet the basic requirements of precise positioning both in static positioning and in dynamic positioning but also can positioning under the obstacle environment of NLOS,and achieve high precision positioning at the same time..The main contents of this paper are as follows:(1)This paper analyzes the definition,characteristics and principle of UWB positioning technology,and introduces the common methods of TOA,TDOA,AOA and RSSI and so on.The Fang/Taylor algorithm,based on the principle of TDOA method is introduced in detail.According to the situation that the Fang algorithm in the non-line of sight error accuracy decreased significantly,we proposed the Fang-Taylor union algorithm which can anti NLOS error.And combined with the positioning performance evaluation index,we use simulation shows its effectiveness.(2)The PC program which is needed for the AGV positioning system is designed.At first we analyzed the demand of the program,then for serial data read function,scientific computing,data storage function and visual operation function which is needed by the program,we used C#.net and Matlab mixed-programming technology developed the program in modules.After that we designed the AGV test platform which is required for the actual verification,analyzed the principle and application of AGV wheel train structure and introduced its function and parameters of each module.This provided a carrier for the actual verification of the performance of the UWB positioning system.(3)The layout of the actual verification environment is presented,and the parameters and position coordinates of each equipment are introduced.In the actual process of verification,the range error of each base station is fitted and corrected.Then we did the static positioning test of the UWB positioning system and analyzed the results of the algorithm before and after optimization.After that,through the actual parameters,we compensated the dynamic positioning algorithm of AGV,and then we did the dynamic positioning experiment.The positioning results are also analyzed and discussed.Finally,we designed the flow pattern of the navigation based on the UWB positioning system.Based on the above theoretical study and specific design,the high precision and high flexibility positioning navigation requirements of AGV are realized.The experiment results show that the positioning accuracy can reach centimeter level in the dynamic and static scene,and can achieve high positioning accuracy under the influence of the NLOS error,which can meet the requirements of AGV normal driving and positioning.