【作者】 蔡晓敏；

【导师】 李一兵；

【作者基本信息】 清华大学 ， 机械工程， 2004， 硕士

【摘要】 常见的事故类型通常都伴随着车辆的碰撞变形,事故车辆动能的一部分在碰撞中转化为变形能。表征变形能大小的等效碰撞速度是交通事故再现分析中的重要参数。对事故车辆的变形程度进行勘查测量是估计等效碰撞速度的必要环节。目前由交通事故鉴定人员到事故车辆停放现场,使用皮尺等工具对其进行传统的手工测量。论文提出了一种基于近景摄影测量的DLT(直接线性变换)模型的事故车辆勘查新方法。鉴定人员对事故车辆进行符合一定规范的拍摄,再将拍摄得到的多张照片导入本文开发的PhotoCrash程序,通过人机交互PhotoCrash程序根据这些照片建立事故车辆的DLT模型,提取车辆上特征点的三维空间位置信息,计算变形数据,输出二维的变形俯视图并估算等效碰撞速度。相比传统的勘查方法,此方法大大提高了车辆勘查效率和质量,精度高,具有可重现性。论文采用考虑了不正交性误差、比例尺不一致误差以及一阶非线性误差的DLT数学模型,在满足事故车辆勘查精度的要求下建立了DLT算法模型,给出了详细完整的解算待测点外部空间坐标的过程。论文根据事故类型和损坏部位对事故车辆进行分类,分析了不同类别的事故车辆等效变形量的解算方法,在阐述力与变形的数学模型基础上,给出了针对不同类别的等效碰撞速度估算方法。论文从硬件和软件两个方面阐述了事故车辆碰撞变形分析系统的设计思想,详细介绍了系统硬件的构成及主要部件的选取,以及PhotoCrash程序的编程实现。最后,以真实的事故案例的应用,说明了本研究在道路交通事故再现分析中的实用性。更多还原

【Abstract】 Traffic accident will generally lead to vehicle’s impact crash, and part of kinetic energy of the damaged vehicles is transferred to deformation energy. EBS (Equivalent Barrier Speed) related to the magnitude of deformation energy is an important parameter for traffic accident reconstruction analysis. For evaluating EBS, it is indispensable process to survey the extent of the damaged vehicle’s crash. Currently, the measurement method is still traditional and being done manually by the traffic accident authenticator with tape measure.The thesis presents a new method based on DLT (Direct Linear Transform) model of close photogrammetry to survey damaged vehicle. It requires that authenticators take photos from the damaged vehicle following some criterion, and then load the photos satisfying requirements into the PhotoCrash program developed by the author. Now via PhotoCrash with human-machine interactive interface, authenticator can build the damaged vehicle’s DLT model according to these photos, pick up the 3D positional information of the vehicle, calculate the crash data, output 2D crash aerial view and evaluate the value of EBS. Compared to traditional method, this application consists of following advantages: high efficiency and perfect performance for surveying vehicle, low artificial error, high precision and good reappearance.This method introduces the DLT mathematic model, which takes the following errors into consideration: non-orthogonal error, scale disaccord error and one order nonlinear error. The DLT arithmetical model is studied to satisfy the precision requirement for surveying vehicle. And complete procedure is described on how to figure out the outer spatial coordinates of unknown points.In the thesis, the damaged vehicle is classified by accident type and damaged position. Calculation methods are studied on equivalent crash value of different kinds of damaged vehicles. In addition, the thesis illuminates <WP=5>mathematic model of the impact force and residual crash, and provides the experiential equations about EBS.This thesis introduces the design idea of damaged vehicle’s impact crash analysis system in both hardware and software sides. Moreover, the system’s hardware structure, selection of main components and programming of PhotoCrash software are presented in detail.Finally, the system’s practicability in road traffic accident reconstruction analysis is validated by the application to real accidents.更多还原