汽车动态仿真器运动系统的两种驱动算法模拟逼真度分析与比较

本文利用驾驶员前庭系统模拟型分析比较汽车动态仿真器运动系统的两种驱动自满的模拟逼真度。仿真结果表明，自适应Ｗａｓｈｏｕｔ驱动算法比传统Ｗａｓｈｏｕｔ驱动算法具有更高的模拟逼真度，因此，汽车动态仿真器用自适应算法可为驾驶员提供更为逼真的运动感觉 。     

开发型驾驶模拟器体感模拟算法及其评价

运用开发型汽车驾驶模拟器，可在模拟的汽车驾驶环境中，研究人－车－环境闭环系统特性，从而研制出高主动安全性汽车，驾驶员的视觉，听觉，触觉及体感是模拟器的四大模拟要素，直接影响模拟器逼真度，本文提出一种驾驶员体感模拟滤波算法，并建立驾驶员体感评价模型，仿真计算的结果表明，该算法既可充分发挥体感模拟系统硬件的模拟能力，并获得满意的体感模拟逼真度，又可为研制汽车驾驶模拟器需体感模拟软件的逼真度评价提供一种行之有效的方法。     

汽车动态仿真器运动系统的软件限制方法

汽车动态仿真器中，驾驶员的运动感觉是由运动系统提供，运动感觉的真实性是影响仿真器逼真度的因素之一，提出了一种从软件上限制仿真器运动系统运动速度，位移的方法，建立了其模型，编制了程序，并用于实际的仿真器系统。     

汽车动态仿真器运动系统控制算法研究

汽车动态仿真器的研制必须建立在驾驶员视觉，触觉，听觉及体感的高逼真度模拟的基础上，研究了体感模拟技术的算法及建模，并进行了计算机仿真，仿真结果表明，所研究的运动控制算法，可为驾驶员提供逼真的运动感觉，可用于汽车动态仿真器的开发研究中心。     

基于反馈控制的人体颈部肌肉主动力建模

鉴于用于汽车交通事故仿真研究的人体有限元模型中肌肉主动力的缺失,制约着人体损伤机理的全面认知,建立肌肉主动力数学模型,获得生物逼真度高的仿真结果,以评估主动安全系统的功效,具有重要意义。本文中基于人体头颈部有限元模型,采用LS-DYNA关键字编写反馈控制程序,对颈部肌肉实现肌肉主动力控制,在有限元模型中实现肌肉主动力模拟,并与基准模型和志愿者碰撞试验进行对比分析,结果表明,添加了肌肉主动力反馈控制的头颈部有限元模型的动力学仿真结果更贴近乘员的真实响应,肌肉主动力在提高有限元人体模型生物逼真度方面具有重要作用。     

清连公路虚拟仿真系统模型的优化研究

针对公路虚拟仿真系统模型的逼真度和实时性之间的矛盾,结合清连公路本身的特点,重点阐述公路三维模型简化的方法和影像数据的多分辨率显示方法,大大提高了虚拟仿真模型的实用性。     

人-车-路虚拟仿真系统研究

虚拟仿真技术具有高度沉浸感和实时交互的特点，已成为研究人-车-路系统协调性的重要技术手段。提出了人-车-路虚拟仿真系统的结构，并在基于Creator的基础上，虚拟了场景建模、驾驶人车速控制模型、车辆动力学模型，基于Vega视景仿真的基础上进行了软件开发。通过应用碰撞检测、三通道视景同步显示、Multi—Agent车辆行为建模等技术提高了场景的渲染逼真度，获得了良好的虚拟仿真效果。     

模糊控制理论在驾驶员—汽车—环境闭环系统操纵稳定性研究中的应用

本文采用模糊控制理论方法，对驾驶员－汽车－环境闭环系统的操纵稳定性进行了研究，建立了驾驶员智能模型，研制了整个闭环系统的仿真软件，模拟了几种典型工况的汽车运行，试验证明闭环系统模型合理，仿真结果正确。     

基于AMESim的汽车制动踏板感觉仿真及优化

为研究与优化汽车制动踏板感觉,对汽车制动系统进行动力学理论分析,基于AMESim建立制动踏板感觉仿真模型,利用实车动态试验验证了模型的准确性,基于建立的模型研究了汽车制动系统各部件参数和踏板踩踏速度与制动踏板感觉的关系,引入制动踏板感觉指数(BFI)对试验车进行了客观评价,并提出制动系统的改善方案。试验结果表明,调整踏板杠杆比、制动器等效弹簧刚度等制动系统参数能够显著提升车辆的制动踏板感觉。     

汽车制动踏板特性仿真及踏板感觉优化

围绕汽车的制动踏板特性展开研究,揭示了制动减速度、制动管路压力、踏板位移以及踏板力之间的变化关系。建立面向制动踏板感觉的制动系统各元件的动力学模型,并在AMESim软件中建立相应的静态/动态仿真模型,结合实车试验验证了仿真模型。基于模型研究了橡胶反作用盘刚度以及制动软管变形对踏板特性的影响。采用制动踏板感觉指数(Brake Feeling Index,BFI)评价体系对试验样车的制动踏板进行客观评价,并提出了优化方案。优化结果表明,通过减小制动盘与制动块之间的间隙,提高制动软管杨氏模量以及橡胶反作用盘刚度等措施,能够显著改善现有的制动踏板感觉,从而为设计出具有良好踏板感觉的制动系统奠定理论基础。     

基于计算机仿真的公路安全设计方法

对公路安全设计与评价方法进行了分析,提出了基于计算机仿真的公路安全设计方法。该方法以ADAMS(AutomaticDynamicAnalysisofMechanicalSystem)软件为平台,通过建立汽车、驾驶员和三维道路等系统仿真模型,为公路设计安全评价提供虚拟对象。在计算机上运行这些模型,获得汽车实时行驶速度,以此可以评价公路线形设计参数是否满足汽车行驶的要求,从而达到评价设计指标安全性的目的。该方法为公路安全设计评价提供了"活的数学模型",这些模型具有参数容易修改、数据表达直观、试验速度快和节省费用等优点。     

Influence of wheel–rail contact modelling on vehicle dynamic simulation

This paper presents a comparison of four models of rolling contact used for online contact force evaluation in rail vehicle dynamics. Until now only a few wheel–rail contact models have been used for online simulation in multibody software (MBS). Many more models exist and their behaviour has been studied offline, but a comparative study of the mutual influence between the calculation of the creep forces and the simulated vehicle dynamics seems to be missing. Such a comparison would help researchers with the assessment of accuracy and calculation time. The contact methods investigated in this paper are FASTSIM, Linder, Kik–Piotrowski and Stripes. They are compared through a coupling between an MBS for the vehicle simulation and Matlab for the contact models. This way the influence of the creep force calculation on the vehicle simulation is investigated. More specifically this study focuses on the influence of the contact model on the simulation of the hunting motion and on the curving behaviour.     

Optimisation of nonlinear motion cueing algorithm based on genetic algorithm

Motion cueing algorithms (MCAs) are playing a significant role in driving simulators, aiming to deliver the most accurate human sensation to the simulator drivers compared with a real vehicle driver, without exceeding the physical limitations of the simulator. This paper provides the optimisation design of an MCA for a vehicle simulator, in order to find the most suitable washout algorithm parameters, while respecting all motion platform physical limitations, and minimising human perception error between real and simulator driver. One of the main limitations of the classical washout filters is that it is attuned by the worst-case scenario tuning method. This is based on trial and error, and is effected by driving and programmers experience, making this the most significant obstacle to full motion platform utilisation. This leads to inflexibility of the structure, production of false cues and makes the resulting simulator fail to suit all circumstances. In addition, the classical method does not take minimisation of human perception error and physical constraints into account. Production of motion cues and the impact of different parameters of classical washout filters on motion cues remain inaccessible for designers for this reason. The aim of this paper is to provide an optimisation method for tuning the MCA parameters, based on nonlinear filtering and genetic algorithms. This is done by taking vestibular sensation error into account between real and simulated cases, as well as main dynamic limitations, tilt coordination and correlation coefficient. Three additional compensatory linear blocks are integrated into the MCA, to be tuned in order to modify the performance of the filters successfully. The proposed optimised MCA is implemented in MATLAB/Simulink software packages. The results generated using the proposed method show increased performance in terms of human sensation, reference shape tracking and exploiting the platform more efficiently without reaching the motion limitations.     

Development of discomfort evaluation method for car ingress motion

Recent improvements in the quality of life have led to a consumer need for emotional quality. This need is regarded as extremely important, particularly for products that require a close interaction between products and users and thus that directly lead to product purchase. As a result, research on how to design user-friendly products has become an important task for corporations. Discomfort evaluation in product use has been extensively researched for this purpose. Most of the research concludes that the joint angles of the human body are the main cause of discomfort and propose a discomfort evaluation method based on joint angles. In general, when a person uses great force, they feel discomfort, and the level of discomfort varies depending on the size of the force. Accordingly, it can be inferred that the force acting on the muscle is one of the important causes of discomfort, and research on the correlation between discomfort and muscle forces is needed. In this study, the authors developed a method to evaluate discomfort during ingress into a vehicle to design a side panel for comfortable ingress into a vehicle. The correlation between the muscle forces and discomfort was investigated, and a discomfort evaluation method based on muscle forces was developed. To calculate the muscle forces during the ingress motion, an experimental mock-up of a vehicle was made, and a motion capture experiment during the ingress motion was conducted with various side panel design parameters. The biomechanical simulation tool was used to perform motion simulation based on the motion data obtained. The mathematical correlation between the calculated muscle forces and discomfort was obtained by means of fuzzy logic, and the discomfort evaluation method developed in this study was used to propose a method for designing a comfortable side panel for a vehicle.     

Analysing classes of motion drive algorithms based on paired comparison techniques

A paired comparison experiment using 23 subjects was run on the VIRTTEX driving simulator to compare a lane position based motion drive algorithm (MDA) with a classical MDA for a highway speed, lane change manoeuvre. Two different tuning states of the lane position algorithm and four different tuning states for the classical algorithm were tested. The subjective fidelity of the six different motion cases was compared with each other and a Bradley–Terry model was fit to find the fidelity merit of each case. In addition, the driving performance of the subjects for six motion cases was recorded and compared. The motion-tuning cases were selected such that the trade-off in motion quality between overall motion scaling and motion shape distortion (shape-error), as well as the trade-off between lateral specific force and roll-rate motion errors, could be studied. It was found that when the overall scaling is the same, drivers perform better with the lane position algorithm than with the the classical algorithm. A well-tuned, manoeuvre-specific, classical MDA, however, did achieve a subjective fidelity level on a par with the lane position MDA. A generically tuned classical MDA, however, has a significantly reduced fidelity and driving performance when compared with a lane position algorithm with the same scale factor. A strong trade-off between motion shape-errors and overall motion scaling was found. A small increase in motion cue shape-error, combined with an increase in the scale factor from 0.3 to 0.5, led to improved performance and increased subjective fidelity. The results of the experiment also suggest that simulator motion can be improved by reducing the angular-rate shape-error at the expense of the specific force shape-error (while keeping the total normalised shape-error constant).     

High fidelity quasi steady-state aerodynamic model effects on race vehicle performance predictions using multi-body simulation

We described in this paper the development of a high fidelity vehicle aerodynamic model to fit wind tunnel test data over a wide range of vehicle orientations. We also present a comparison between the effects of this proposed model and a conventional quasi steady-state aerodynamic model on race vehicle simulation results. This is done by implementing both of these models independently in multi-body quasi steady-state simulations to determine the effects of the high fidelity aerodynamic model on race vehicle performance metrics. The quasi steady state vehicle simulation is developed with a multi-body NASCAR Truck vehicle model, and simulations are conducted for three different types of NASCAR race tracks, a short track, a one and a half mile intermediate track, and a higher speed, two mile intermediate race track. For each track simulation, the effects of the aerodynamic model on handling, maximum corner speed, and drive force metrics are analysed. The accuracy of the high-fidelity model is shown to reduce the aerodynamic model error relative to the conventional aerodynamic model, and the increased accuracy of the high fidelity aerodynamic model is found to have realisable effects on the performance metric predictions on the intermediate tracks resulting from the quasi steady-state simulation.     

行人交通仿真模型与相关软件的对比分析

从描述行人运动行为的尺度和精细程度出发，行人交通仿真模型分为宏观模型、中观模型和微观模型3类。总结了常见的格子气模型、元胞自动机模型、社会力模型和磁力模型的原理及算法，对比分析了其仿真效果。论述了如何运用Legion、STEPS、SimWalk和AnyLogic软件建立行人交通仿真模型，比较和评述了上述软件的技术性能。研究表明，充分、合理利用已有软件，可实现快速有效的行人交通仿真建模。