The Investigation Of Cooperative Adaptive Cruise Control Strategy Optimization And Simulation System

With the rapid development of autonomous driving and onboard communication technologies,Connected Autonomous Vehicles(CAVs)cooperative platooning technology is expected to further improve traffic efficiency and safety.In this paper,the cooperative adaptive cruise control technology of connected CAVs is taken as the main research object.Through theoretical analysis,system modeling,and simulation experiments,the cooperative driving problem of CAVs platoons in an intelligent networked environment is studied.Based on the key problems in the specific traffic scene,the potential problems of cooperative driving in the mixed zone of the expressway and uncertain network environment are studied.Firstly,based on the sensor-based adaptive cruise control(ACC)formation system,the theory analysis and mathematical modeling of the adaptive cruise platooning system are carried out.The impacts of sensor delay and actuator inertia lag on the adaptive cruise control platooning system are considered in the modeling of the vehicle control system.Based on this system model,the string stability of the ACC platoons is studied.The transfer function of the distance error in the ACC platoons is derived mathematically and the theoretical conditions for maintaining the string stability of the adaptive cruise fleet are obtained.Based on the obtained decision theorem,the stability domain of the gain coefficient of the control algorithm in a twodimensional plane is obtained by numerical calculation,and the acceptable sensor delay boundary is obtained by sensitivity analysis.It not only provides a theoretical basis for the parameter design of ACC systems in engineering practice but also lays a theoretical foundation for further research on intelligent networked autonomous vehicle(CAVs)queue systems.Then,Cooperative adaptive cruise control(CACC)system,a collaborative driving queue control system of CAVs vehicles in intelligent network environment,is studied.However,the time delay of the cooperative platooning communication system is also an inherent uncertainty of the system,which will seriously limit the performance of intelligently networked vehicle platoons.Therefore,this paper improved the traditional cooperative autonomous driving model and proposed a distributed control model of CAVs platooning control algorithm considering communication time delay.Based on the modified control model,the judgment condition of the string stability of CACC platoons is obtained by the Laplace transform,and then the mathematical model of the parameter design of the CACC control algorithm is obtained.Through numerical analysis and sensitivity analysis,a method is proposed to identify the upper bound of communication delay that the CACC system can tolerate.Finally,through comparative experiments,the validity of the parameter design method proposed in this study is verified from both positive and negative aspects,which lays a solid foundation for further study of CAVs platoons under specific traffic scenarios and provides a theoretical basis for parameter design of distributed collaborative adaptive cruise control algorithm.Further,based on the basic study of the CACC system,this paper investigates the key problems of the cooperative driving of CACC platoons in two special traffic scenarios,one is the cooperative driving of CACC platoons in the weaving area of the expressway,the other is the cooperative driving of CACC platoons in the uncertain network communication security scenario.First of all,as the bottleneck section of the expressway,the problem of cooperative driving of vehicles in the weaving segments is more complicated.Combined with the microtraffic behavior of vehicles in the interweaving zone of an expressway,this paper focuses on the influence of merging and separating traffic flows on the cooperative driving platoons and the corresponding control strategy.To improve the performance of the cooperative driving platoons in the interweaving area,on one hand,the traditional CACC control system framework was improved,and a comprehensive SR-CACC control system framework integrated with a feedforward control module was proposed.On the other hand,in order to alleviate the negative impact of cut-out interference in interleaved areas on collaborative driving vehicles,this study not only proposed a rolling prediction method for lane change behavior of the leading vehicle but also applied it in the feedforward control module of the control system.In addition,a linear smooth transition algorithm is proposed to smooth the cut-in and cut-out interference signals.Finally,simulation verification experiments were carried out based on real vehicle data of NGSIM.The experimental results show that the improved SR-CACC control system in this study can greatly improve the driving stability and safety of the CACC fleet in the interwoven area of the expressway.On the other hand,aiming at the problem of cooperative driving of the CACC fleet under an uncertain network environment,this paper proposes a CAVs cooperative driving control system that can improve the security of vehicle-vehicle communication networks.Specifically,this paper integrates the network attack detection and defense subsystem based on the traditional CACC cooperative driving control system.On the one hand,to detect network attack behavior quickly,this paper proposes a network attack detection method based on a Support Vector Machine(SVM)algorithm.On the other hand,to recover the tampered data,this study proposed a data repair algorithm based on the Extended Kalman filter algorithm(EKF).Then,to verify the effectiveness of the proposed anomaly detection method and data repair algorithm,the control effect of the optimized system in the simulation environment is further verified by simulation verification experiments.The experimental results show that the SVM-based network attack detection method proposed in this study can quickly detect network attacks existing in the system,and its detection speed and accuracy can reach 98.83% accuracy within1 second.It also shows that the data recovery algorithm based on the EKF algorithm proposed in this study can also effectively suppress the impact of network attacks on the collaborative driving fleet.This fully demonstrates the sensitivity and effectiveness of the network attack detection method proposed in this study.Finally,in order to verify the reliability of the algorithm and model studied in this paper and improve the efficiency of subsequent studies,this study designed and developed a traffic simulation verification experiment platform for intelligent networked fleet collaborative driving.The simulation test platform not only considers how to meet the functional requirements of the simulation experiment but also fully considers how to meet the user’s non-functional requirements for convenience of operation,interface aesthetics,and other aspects.Then,the internal working principle and concrete implementation details of the traffic simulation verification experimental platform designed in this study are introduced in detail,which lays a solid foundation for further enriching and expanding the traffic simulation platform in subsequent studies.Based on this research,the simulation and verification experiment platform for intelligent networked vehicle collaborative driving control system designed and developed not only provides a graphic visualization platform for teaching and research personnel,but also lays a foundation for the subsequent perfection and implementation of CAVs vehicle platooning control technology..