基于TAP参数的汽车避撞系统算法的优化与仿真

为帮助驾驶人更好地规避潜在危险,在分析Mazda和Honda汽车避撞系统算法的基础上,提出了一种基于可调避撞参数TAP的主动避撞系统算法,并考虑驾驶人因素,选择了算法的报警方法。简述Mazda、Honda的安全距离逻辑算法,在Mazda算法的基础上引入参数TAP,推导出优化的临界报警距离算法;以Honda算法推导出优化的临界制动距离算法。对该算法和Mazda、Honda算法进行了仿真对比分析,分析结果表明TAP优化算法使系统拥有保守的临界报警距离和非保守的临界制动距离,验证了TAP算法的可行性和优越性。     

汽车纵向主动避撞系统的研究现状与展望

针对现代交通安全问题,提出了一种辅助驾驶员行车安全的方法,即纵向主动避撞,主要围绕汽车纵向主动避撞系统中的行车信息感知与处理、安全距离模型、车辆动力学系统建模、车辆动力学控制四个关键技术进行叙述.各种先进的控制技术为研究汽车纵向主动避撞系统提供了新的机遇,它所衍生出的新功能新系统对汽车的安全性、舒适性及经济性等方面都有...     

禁左条件下车辆掉头行为仿真模型

围绕城市信号交叉口禁止左转弯(简称“禁左”)管理措施的可行性研究,利用城市微观交通仿真技术,建立了禁左条件下车辆掉头行为仿真模型,为分析禁左的效能提供了科学的理论基础。     

微观仿真信号交叉口车辆运动的实现与研究

主要介绍了对信号交叉口的车辆运动的微观仿真研究的思路及具体实现中遇到的问题与思考。首先概述了国内外信号交叉口控制系统和微观仿真系统的发展与现状,接着介绍该文所要实现的信号交叉口微观仿真软体的总体思路和程序流程,并针对各组成部分具体详细说明了实现的方法,进一步探讨了用计算机如何对车辆运动进行描述。最后,构想了在微观仿真平台上研究路口公交优先控制方案并展望了今后的发展。     

基于Agent的驾驶员-车辆建模研究与实现

微观交通仿真技术是解决城市交通网络拥塞问题的有效工具.在各种交通元素中,驾驶员-车辆单元是交通流的主体.该文通过对交通流中驾驶员、车辆特性的分析,将驾驶员和车辆视为一个整体,并基于Agent理论对之进行建模.文中详细分析了Agent的生成和路径搜索及选择算法,研究了Agent的跟驰、换道和挤占道等行为.该文最后介绍了基于Agent模型建立的一种微观交通仿真器,并在该仿真器上进行仿真实验.结果表明该系统能够较好的仿真实际交通流状况.     

两种车辆悬架系统的建模与控制仿真

车辆悬架系统作为汽车的一个重要组成部分,其性能好坏会影响到车辆的平顺性与稳定性。以1/4车辆模型为例,从被动悬架到主动悬架,将车辆悬架系统动力学原理与MATLAB仿真软件相结合,即首先利用动力学理论建立其数学模型,然后在仿真软件中建立其相对应的模型进而动态仿真,最后对比结果。实验结果表明,在车轮动载荷大致相同的条件下,设计的主动悬架有效地降低了车体的垂直加速度,与被动悬架相比,优化了约17%,提高了车辆在行驶过程的平顺性和驾驶的稳定性。     

基于Simscape的车辆ABS建模与仿真研究

关于车辆ABS系统建模优化问题,传统的建模方法缺少具体的车辆组件模型和完善的物理系统模型,且纯数学理论模型较晦涩和理想化.为解决上述问题,提出一种基于Simscape的物理系统建模方法,可以支持不同类型物理系统的复杂过程的混合建模和仿真,比传统模型更具物理性和更切合实际情况,且构建的车辆组件模型具有独立性和通用性.为验证物理系统模型的正确性和真实性,针对干沥青、湿泥土和积雪三种路面条件的刹车过程进行了仿真研究.仿真结果表明,利用Simscape搭建的物理模型是真实可靠的,更有利于对ABS系统高效快捷地开展相关的动力学分析.     

无人驾驶车辆的路口防撞机制研究

防撞协议是提高无人驾驶车辆安全性的重要组成部分,大部分防撞协议已经为路口外的车辆提供了躲避机制.交叉路口因其流量大、方向多而成为事故易发地,但对已在路口内部的车辆的防撞协议的研究比较少.自治路口协议AIM作为目前较流行的路口管理协议之一,也未给出已在路口的车辆的防撞协议.给出了两类基于路口空间的防撞协议:当路口空间较小时,改进的AIM根据三种情况,即同向、逆向、垂直同向,给出了基于刹车的躲避机制;当路口空间较大时,改进的AIM除可以采用基于刹车的躲避机制外,还可以通过转弯为车辆重新规划路线使其通过路口.通过实验证明了改进的AIM的有效性.     

微观交通仿真系统碰撞检测模块设计方法

为了避免在微观交通仿真系统中出现穿透现象,设计了适合微观交通仿真系统的坐标系,建立了系统中主要实体的空间几何等效体,提出了筛选式的检测过程,详细分析了不同实体间的碰撞检测算法,使系统仿真的真实感和实时性得到了较大的提高。     

碰撞防护系统分析及铁路应用设计

在分析既有碰撞防护系统的基础上,首次提出适用于轨道交通领域的列车碰撞防护系统概念,设计了列车碰撞系统的功能架构并定义了各子系统的功能,对比分析了列车碰撞防护系统的两种工作模式.作为列车控制系统的安全叠加系统,列车碰撞防护系统可有效提升铁路运输安全性能.     

Autonomous maritime collision avoidance: Field verification of autonomous surface vehicle behavior in challenging scenarios

We present results from sea trials for an autonomous surface vehicle (ASV) equipped with a collision avoidance system based on model predictive control (MPC). The sea trials were performed in the North Sea as part of an ASV Challenge posed by Deltares through a Dutch initiative involving different authorities, including the Ministry of Infrastructure and Water Management, the Netherlands Coastguard, and the Royal Netherlands Navy. To allow an ASV to operate in a maritime environment governed by the International Regulations for Preventing Collisions at Sea (COLREGs), the ASV must be capable of complying with COLREGs. Therefore, the sea trials focused on verifying COLREGs‐compliant behavior of the ASV in different challenging scenarios using automatic identification system (AIS) data from other vessels. The scenarios cover situations where some obstacle vessels obey COLREGs and emergency situations where some obstacles make decisions that increase the risk of collision. The MPC‐based collision avoidance method evaluates a combined predicted collision and COLREGs‐compliance risk associated with each obstacle and chooses the ‘best’ way out of dangerous situations. The results from the verification exercise in the North Sea show that the MPC approach is capable of finding safe solutions in challenging situations, and in most cases demonstrates behaviors that are close to the expectations of an experienced mariner. According to Deltares’ report, the sea trials have shown in practice that the technical maturity of autonomous vessels is already more than expected.     

自主车辆安全系数估计与T形路口避碰规划

针对自主车辆T形路口协作问题,通过测量车辆速度和预碰点距离,提出安全系数估计方法,结合人工势场基本思想,实现车辆路口避碰,提高路口协作效率.首先以计算得到的安全系数为依据,评价驶入T形路口两辆自主车各自的安全程度,并利用人工势场产生的推拉作用估计协作自主车辆的期望控制力和速度.然后将估计的期望车速与反馈的实际车速形成偏差,利用增量型数字PI控制器实现自主车纵向车速的准确控制.最后以一定的策略完成两辆自主车的并线协作.仿真结果验证了基于安全系数估计的自主车辆T形路口协作避碰的可行性与有效性.     

Adaptive hierarchical artificial immune system and its application in RFID reader collision avoidance

This paper proposes an efficient adaptive hierarchical artificial immune system (AHAIS) for complex global optimization problems. In the proposed AHAIS optimization, a hierarchy with top-bottom levels is used to construct the antibody population, where some antibodies with higher affinity become the top-level elitist antibodies and the other antibodies with lower affinity become the bottom-level common antibodies. The elitist antibodies experience different evolutionary operators from those common antibodies, and a well-designed dynamic updating strategy is used to guide the evolution and retrogradation of antibodies between two levels. In detail, the elitist antibodies focus on self-learning and local searching while the common antibodies emphasize elitist-learning and global searching. In addition, an adaptive searching step length adjustment mechanism is proposed to capture more accurate solutions. The suppression operator introduces an upper limit of the similarity-based threshold by considering the concentration of the candidate antibodies. To evaluate the effectiveness and the efficiency of algorithms, a series of comparative numerical simulations are arranged among the proposed AHAIS, DE, PSO, opt-aiNet and IA-AIS, where eight benchmark functions are selected as testbeds. The simulation results prove that the proposed AHAIS is an efficient method and outperforms DE, PSO, opt-aiNet and IA-AIS in convergence speed and solution accuracy. Moreover, an industrial application in RFID reader collision avoidance also demonstrates the searching capability and practical value of the proposed AHAIS optimization.     

面向车载容迟网络的连通性建模与仿真研究

针对车载容迟网络连通性建模进行了研究。首先假设车辆驶入道路的过程服从泊松分布,以及车辆在道路上的行驶速度服从正态分布。继而对基于泊松过程的车间时距分布进行推导,并以此导出行驶车辆在道路上的连通概率。为了验证所提假设和连通模型的正确性和有效性,以欧洲城市卢森堡在7:30 a.m.~8:30 a.m.时间段内的交通数据为实验场景,在城市交通仿真平台（simulation of urban mobility,SUMO）对车辆速度的概率分布、车辆到达率、道路中的平均车辆数及网络连通概率进行了理论计算和仿真实验分析。实验结果表明理论模型的计算值和仿真结果是一致的,所提出的假设和连通模型具有合理性和正确性。     

Optimal and suboptimal motion planning for collision avoidance of mobile robots in non-stationary environments

An optimal control formulation of the problem of collision avoidance of mobile robots moving in terrains containingmoving obstacles is presented. A dynamic model of the mobile robot and the dynamic constraints are derived. Collision avoidance is guaranteed if the minimum distance between the robot and the objects is nonzero. A nominal trajectory is assumed to be known from off-line planning. The main idea is to change the velocity along the nominal trajectory so that collisions are avoided. Furthermore, time consistency with the nominal plan is desirable. Two solutions are obtained: (1) A numerical solution of the optimization problem and a perturbation type of control to update the optimal plan and (2) A computationally efficient method giving near optimal solutions. Simulation results verify the value of the proposed strategies and allow for comparisons.     

时滞分布参数系统的移动传感器/执行器防碰撞控制

针对一类状态时滞的分布参数系统,考虑了传感器/执行器间的防碰撞问题和最大通讯距离的最小通讯能耗问题,以及系统的稳定性问题.利用抽象发展方程理论和Lyapunov稳定性方法,设计了一种基于时滞分布参数系统的智能体移动控制策略,包括输出反馈控制器和移动控制力.通过理论推导和仿真实验验证,文中设计的控制策略能够使得时滞分布参数系统是渐近稳定的,同时智能体在移动过程中是防碰撞的,也验证了智能体在最大通讯距离的最小能耗.     

Modeling and simulation of overtaking behavior involving environment

Overtaking is a complex driving behavior for intelligent vehicles. Current research on modeling overtaking behavior pays little attention on the effect of environment. This paper focuses on the modeling and simulation of the overtaking behavior in virtual reality traffic simulation system involving environment information, such as road geometry and wind. First, an intelligent vehicle model is proposed to better understand environment information and traffic situation. Then, overtaking behavior model is introduced in detail, the lane changing feasibility is analyzed and the fuzzy vehicle controllers considering the road and wind effect are researched. Virtual reality traffic simulation system is designed to realize the simulation of overtaking behavior, with realistic road geometry features. Finally, simulation results show the correctness and the effectiveness of our approach.