【作者】 于晓杰；

【导师】 韩士元； 李凡军；

【作者基本信息】 济南大学 ， 计算机技术（专业学位）， 2022， 硕士

【摘要】 由于现如今汽车保有量急速增长而引起的道路拥挤和安全事故等交通问题日益严重,引发了巨大的人员伤亡和经济损失。驾驶员的判定失误、决策失误等人为因素是引发“幽灵堵车”和一系列交通事故的主要原因。自动驾驶的出现减少了因驾驶员原因而造成交通堵塞等交通事故的发生。在自动驾驶的初级阶段,协同自适应巡航控制(Cooperative Adaptive Cruise Control,CACC)是最先实现并能部署于实际的技术。CACC技术对于改善交通安全性、降低交通能耗、提高交通效率等方面有很大的提升。然而,CACC技术是一种基于队列中车与车之间通信的技术,因此,车联网引起的通信时延是不可避免的。本文以通信时延影响作为研究背景,纵向队列车辆作为控制对象,将车辆关联特性融入到车间距策略中,分别对集中式和分散式控制建立通信时延影响下纵向队列车辆CACC系统模型,进行自适应巡航控制策略的设计和优化,来减少通信时延对CACC控制性能的影响。主要内容如下:(1)通信时延影响下车辆协同自适应巡航控制系统集中纵向控制策略设计。从大规模队列关联系统的角度出发,集中式纵向队列车辆协同自适应巡航控制问题能够被抽象表示成大规模离散时间系统的最优跟踪问题;提出一种时延转换模型,将原本具有执行器和通信时延的大规模离散时间系统的最优跟踪控制问题转化为无时延的两点边值问题;通过求解Riccati方程,获得唯一的最优协同自适应巡航控制器。实验结果表明,所设计控制器可有效缩小车间距、降低能源消耗,同时补偿时延对控制性能的影响。(2)车间通信时延影响下纵向队列车辆CACC关联系统的稳定性分析。从单项强耦合特性的角度出发,分散式纵向队列车辆自适应巡航系统模型可以描述为具有通信时延和车辆关联特性的大规模离散关联系统的约束模型;利用部分分解法和李雅普诺夫函数,将具有强耦合特性的系统离散时间模型分解为单向解耦的低阶子系统,从而分析证明纵向队列车辆CACC关联系统的稳定性,并基于李亚普诺夫函数和线性矩阵不等式获取得到确保队列车辆系统稳定的通信时延上界。(3)通信时延影响下纵向队列车辆协同自适应巡航分布式模糊PID策略设计。基于车间通信时延范围,建立模糊系统描述纵向队列被控车辆与其他车辆之间关联有效性关系;采用队列车辆的相对速度参数作为主要输入量,根据不同的行驶状态设计纵向队列车辆协同自适应巡航控制模糊PID策略。仿真结果证明可以有效补偿通信时延的影响,并能够保证安全性和舒适性。更多还原

【Abstract】 The number of cars ownership in today’s world has surged,resulting in increasingly serious problems such as traffic jams and safety accidents,resulting in huge casualties and economic losses.Drivers’ misjudgment and decision-making are the main causes of "ghost traffic jam" and a series of traffic accidents.The emergence of automatic driving reduces the occurrence of traffic accidents such as traffic jams caused by drivers.In the initial stage of automatic driving,cooperative adaptive cruise control(CACC)is the first technology to be realized and deployed in practice,which has a great improvement in improving traffic safety,reducing traffic energy consumption and improving traffic efficiency.However,CACC technology is also a technology based on the communication between vehicles in the platoon.Therefore,the communication delay caused by vehicle networking is inevitable.Taking the communication delay as the research background and the longitudinal platoon vehicles as the control object,this paper integrates the vehicle correlation characteristics into the vehicle spacing strategy,establishes the CACC system model of longitudinal platoon vehicles under the influence of communication delay for centralized and decentralized control respectively,and designs and optimizes the adaptive cruise control strategy to reduce the influence of communication delay on CACC control performance.The main contents are as follows:(1)Centralized longitudinal control strategy design of vehicle cooperative adaptive cruise control system under the influence of communication delay.From the perspective of large-scale queue correlation system,the centralized longitudinal queue vehicle cooperative adaptive cruise control problem can be abstractly expressed as the optimal tracking problem of large-scale discrete-time system;A time delay transformation model is proposed to transform the optimal tracking control problem of large-scale discrete-time systems with actuator and communication delays into a two-point boundary value problem without delay;The unique optimal cooperative adaptive cruise controller is obtained by solving the Riccati equation.The experimental results show that the designed controller can effectively reduce the vehicle spacing and energy consumption,and compensate the influence of communication delay on the control performance.(2)Stability analysis of longitudinal platoon vehicle CACC correlation system under the influence of workshop communication delay.From the perspective of single strong coupling characteristics,the decentralized longitudinal platoon vehicle adaptive cruise system model can be described as a constraint model of large-scale discrete correlation system with communication delay and vehicle correlation characteristics;Based on Lyapunov’s method,the vehicle platoon is decomposed into a discrete linear subsystem with time delay,and the stability of the vehicle platoon is proved based on the Lyapunov’s method.(3)Design of distributed fuzzy PID strategy for cooperative adaptive cruise of longitudinal platoon vehicles under the influence of communication delay.Based on the communication delay range of workshop communication,a fuzzy system is established to describe the association effectiveness relationship between the controlled vehicle in longitudinal platoon and other vehicles;Using the relative speed parameters of platoon vehicles as the main input,the fuzzy PID strategy of cooperative adaptive cruise control for longitudinal platoon vehicles is designed according to different driving states.The simulation results show that it can effectively compensate the influence of communication delay and ensure safety and comfort.更多还原