Design Of Intelligent Vehicle Formation System Based On UWB

With the continuous development of autonomous driving technology,the autonomous formation technology of intelligent vehicles has received more and more attention from people.By carrying advanced sensors and using advanced communication and control technology on the intelligent vehicle,it can realize the formation of multiple vehicles.In the intelligent vehicle formation,the front and rear intelligent vehicles maintain a reasonable inter-vehicle distance,which can increase the traffic flow on the road,improve the traffic efficiency and the safety of vehicles.In vehicle autonomous formation,we need to consider vehicles’ positioning and communication,but the existing vehicle positioning methods,such as satellite positioning,lidar positioning and vision positoning,they all have their own limitations,and vehicle positioning and communication are separated.In view of the above problems,this paper has completed the following work :Firstly,this paper proposes a method based on UWB in order to solve the shortcomings of the current methods which are used for locating the intelligent vehicles.The technology of UWB can be used to locate a vehicle and realizes vehicle-to-vehicle communication.It has a simple system structure.It can transmit data at high speed safely and locate the vehicle precisely.Secondly,the paper improves the method of TDOA based on UWB module.This paper proposes to use the Kalman filter algorithm to improve the time synchronization accuracy of the master and slave stations which caused by the problems of clock deviation and frequency offset in the TPSN synchronization algorithm.Then,it reduces the errors of external noise and interference in the location by adding a UWB reference station.Lastly,in order to improve the accuracy in the solution of location based on UWB,it proposes a simple iterative least square method to reduce the location error through iterative calculation.Thirdly,in order to solve the shortcomings of the existing control algorithm of the safe distance,the paper uses UWB to communicate between the rear vehicle and the front vehicle,so that the rear vehicle can quickly obtain the motion state of the front vehicle.Then it can follow the front vehicle with a stable and safe inter-vehicle distance.Fourthly,it builds the hardware platform of the intelligent vehicle,and on the basis of the built hardware platform,it designs the software of the UWB positioning module,the lowerlevel controller and the upper-level controller respectively.Finally,it carries out two tests that including location of intelligent vehicles and longitudinal formation in the built test environment.The test results show that the improved UWB localization algorithm based on TDOA can achieve more accurate location of the target intelligent vehicle.At the same time,combined with control algorithm to improve the safe intervehicle distance,the three intelligent vehicles can drive in a longitudinal formation safely and stabely under different motion states.