Research On Formation Control Of Multi-intelligent Vehicles Based On Path Tracking

As an important research content in the development of intelligent transportation system(ITS),multi intelligent vehicle formation can make full use of road capacity,improve road traffic efficiency and vehicle fuel economy,and effectively alleviate social problems such as traffic congestion,accident frequency and resource shortage under the premise of considering road traffic safety.Therefore,it has become the focus of research and application in transportation developed countries.The main problem of formation control of multi-agent vehicles is that the whole formation system can have enough formation expansibility to meet the requirements of cooperative driving,lane changing and obstacle avoidance,and ensure the stability of sub vehicles in formation.Therefore,formation control research can be divided into formation organization and motion tracking control The research is carried out from two aspects.Aiming at the problems of low accuracy and poor stability of intelligent vehicle path tracking control,a path tracking control strategy of four-wheel steering combined differential braking based on hierarchical architecture was proposed.The upper layer designed the front wheel active steering controller based on the linear dynamic model;the lower layer used the sliding mode variable structure control theory to design the integrated controller of rear wheel steering and additional yaw moment,and established the differential braking distribution strategy,which transformed the additional yaw moment into single wheel braking control,has realized the joint control of four-wheel steering and differential braking,and improved the accuracy of intelligent vehicle path tracking Accuracy and stability.In view of the poor expansibility of multi-agent vehicle formation control,inflexible formation transformation and unsatisfactory response under obstacle avoidance conditions,based on path tracking formation control method,a multi-agent vehicle formation collaborative control strategy combining artificial potential field and virtual structure was proposed,in which virtual structure was used to design formation,generate desired formation reference point,and define intermediate medium Point tracking the desired reference point and adding the function terms of collision avoidance and obstacle avoidance potential field through artificial potential field method,the combination of the two methods forms the formation organization layer of formation system,and realized formation organization and obstacle avoidance transformation in dynamic environment.The intelligent vehicle tracked the intermediate medium points through the path tracking control,and generates the designated formation gradually without collision,so as to realize the cooperative driving of multiple vehicles.In order to verify the effectiveness of the proposed formation control strategy,a simulation platform of formation control system including formation organization layer and path tracking layer is built based on MATLAB / SIMLINK software,and the verification simulation of path tracking control and formation control has been carried out.In the aspect of path tracking,the simulation results show that compared with the front wheel steering control only,the peak value of lateral tracking error is reduced by 37.9%,the peak value of yaw angle error is reduced by 50.6%,and the peak value of lateral acceleration is reduced by 29.8%.The accuracy and stability of vehicle path tracking are significantly improved.In the aspect of formation control,the simulation experiments of linear formation and curve formation under multi vehicle obstacle avoidance conditions are carried out.The simulation results show that the proposed formation algorithm can be effectively applied to the multi intelligent vehicle cooperative formation,with good formation scalability and ensuring the safe and cooperative driving of multiple vehicles.