整车路面不平度激励的仿真方法研究

分析了路面不平度对三轴式整车的随机激励输入,利用白噪声法和传递函数法推导 得出整车六轮路面不平度输入的状态方程。在Matlab/Simulink 中搭建二维路面不平度数学模型, 并与标准路面不平度进行了比较和验证,说明了搭建模型的准确性。通过整车状态方程搭建六轮 路面不平度数学模型,仿真结果说明了同车桥的左右两车轮的功率密度谱差异较大,同侧前后车 轮的功率密度谱差异较小,比较符合多车桥式重卡的实际情况,且均在标准路面不平度功率密度 谱的标准范围内。为了进一步验证仿真结果,对整车六轮的路面不平度互相关系数进行了分析, 分析结果与上述结论吻合。     

加速度计信号处理的建模与仿真

研究车载公路路面平整度动态测量系统的优化设计问题,加速度计输出信号的二次积分用于修正路面高程数值,由于目前处理一维加速度计信号的方法中均不能滤除混入的标度因数误差。为解决上述问题,提出根据卡尔曼滤波原理建立标定车载道路路面平整度检测单元中一维加速度计混入的零偏差和标度因数误差的卡尔曼滤波模型,并使用MATLAB软件上进行仿真,仿真结果表明建立的卡尔曼滤波模型可以有效估计和滤除加速度计输出信号中混入的固有零偏差、标度因数误差和随机白噪声,为优化设计提供了依据。     

基于ABAQUS的沥青路面有限元仿真模型研究

阐述沥青路面水损坏机理,介绍ABAQUS有限元仿真软件,利用ABAQUS非线性动态分析能力建立了沥青路面渗流场、应力场三维有限元数值模型,对孔隙水压力、三向应力及竖向沉降的发生及变化规律进行探讨,并在某高速公路上建立试验段进行试验验证。由算例分析可知,用ABAQUS有限元软件模拟沥青路面降雨条件下的渗流场及移动荷载下的应力场是可行的,效果良好。     

Vibration control of vehicle active suspension system using a new robust neural network control system

The main problem of vehicle vibration comes from road roughness. For that reason, it is necessary to control vibration of vehicle’s suspension by using a robust artificial neural network control system scheme. Neural network based robust control system is designed to control vibration of vehicle’s suspensions for full suspension system. Moreover, the full vehicle system has seven degrees of freedom on the vertical direction of vehicle’s chassis, on the angular variation around X-axis and on the angular variation around Y-axis. The proposed control system is consisted of a robust controller, a neural controller, a model neural network of vehicle’s suspension system. On the other hand, standard PID controller is also used to control whole vehicle’s suspension system for comparison.Consequently, random road roughnesses are used as disturbance of control system. The simulation results are indicated that the proposed control system has superior performance at adapting random road disturbance for vehicle’s suspension.     

Active control for the suspension of large-sized buses using fuzzy logic

An active suspension of large-sized buses by using fuzzy logic is considered. The active control for the suspension is determined by minimizing the mean squares of vertical and rotary accelerations of vehicle body subject to the constraints of suspension and tyre deflections. The vehicle model is assumed to be a linear system with six degrees of freedom excited by road profiles. The tuning of fuzzy control rules and associated parameters that characterize the active control is carried out where two kinds of road profiles are considered. In the simulation results, the proposed active suspension shows improved performance over passive suspension     

基于分形理论的三维路面谱重构及在多体动力学软件中的应用

合理的道路纹理特征可以更好地反映路面抗滑性能和轮胎/路面接触特性。基于分 形理论提出了一种三维路面谱重构方法。依据国标给出二维随机路面谱的时域表达,利用计盒 维数法计算各级路面分形维数,综合应用随机中点位移法和分形布朗运动原理将传统二维路谱 拓展为三维路面谱。以典型的减速带为例,将特殊激励同构到含有细节形貌的平整路面谱中。 在 TruckSim 软件中通过编译实现三维路面谱在车辆多体动力学软件中的应用。通过对比二维路 谱和三维路谱下车辆动力学响应发现：垂向力和纵向力差异不大,有较好地一致性,但侧向力 相差比较大,表明所建立的三维路面谱有较好精度的同时反映了路面的三维纹理特性,为车辆 曲线通过性能和车辆侧翻控制研究提供了基础。     

前梁对汽车前轮摆振的影响分析及仿真研究

某重型车在行驶时常出现前轮摆振现象,为此对前梁进行了建模和仿真分析.首先使用Pro/E建立前梁模型;接着使用Pro/M对其进行静态分析,分析了车辆直线行驶和转弯行驶时前梁的变形情况,并对前梁进行了模态分析,得到其前8阶固有频率和振型,通过振型分析了前梁的动态性能;最后使用SIMULINK模块仿真分析了前梁在B级路面上速度为50km/h时由路面不平度引起的随机振动.结果表明:满载行驶时,前梁在路面不平度的激励下产生的垂直位移满足行业标准,固有频率远离路面不平度激励下的频率,不会产生共振而导致摆振.但是转弯时前梁主销偏移距过大易引起前轮摆振,应适当减小其内倾角角度来避免转弯时摆振的发生.     

Sensitivity analysis and optimization of vehicle–bridge systems based on combined PEM–PIM strategy

This paper presents a new optimization method for coupled vehicle–bridge systems subjected to uneven road surface excitation. The vehicle system is simplified as a multiple rigid-body model and the single-span bridge is modeled as a simply supported Bernoulli–Euler beam. The pseudo-excitation method transforms the random surface roughness into the superposition of a series of deterministic pseudo-harmonic excitations, which enables convenient and accurate computation of first and second order sensitivity information. The precise integration method is used to compute the vertical random vibrations for both the vehicle and the bridge. The sensitivities are used to find the optimal solution, with vehicle ride comfort taken as the objective function. Optimization efficiency and computational accuracy are demonstrated numerically.     

汽车振动的一种模糊自适应控制

该文研究了一种汽车模糊自适应控制方法,并借助于一个二自由度的汽车动力学模型,探讨了该模糊自适应控制技术在汽车车身主动减振方面的控制问题。在测得汽车垂直振动强度,行驶速度等条件下,在保持各个状态变量和控制量的模糊集数量不变的情况下,通过自动调整模糊集的相应大小与相应中央位置,仿真研究表明,该自适应模糊控制器使汽车在不同路面波度大小,行驶速度等情况下的车身振动强度均能大幅度下降,达到主动减振的目的。其原理与方法可用于研制简单可靠的模糊控制主动悬架。     

影响流量管流量系数的因素分析

对某航空发动机整机试验装置的流量管三维流场进行数值模拟,通过布置虚拟测点,建立流量管虚拟试验校准和测量的仿真方法,研究流量管流量系数获取方法、校准试验测试布局,分析来流雷诺数、壁面粗糙度、流量管圆度对流量系数的影响。结果表明,附面层位移厚度法和校准试验法获取的流量系数接近。在同一流向布置测量截面,流量系数随流量管内雷诺数的减小而减小,随流量管壁面粗糙度的增大而减小;低雷诺数工况下,流量系数对粗糙度变化不敏感。对于低雷诺数工况或者在流量管壁面粗糙度较大时,应采用附面层位移厚度法或校准试验法获取流量系数。流量系数对流量管圆度的变化不敏感,建议采用校准试验方法获得有变形的流量管的流量系数。尽量采用校准试验法获取流量管宽雷诺数范围的流量系数,采用实际测量工况下的雷诺数对应的流量系数,修正流量管测量数据,才可保证流量管测量精度。     

防抱制动系统滑模状态观测和控制系统仿真

该文在考虑不平路面随机激励作用下车辆垂向振动的基础上 ,首先建立了四分之一车辆制动模型 ,而后充分运用滑移模式变结构的分析和设计方法 ,提出了车轮最佳滑移率的滑模实时在线辨识滑模优化算法 ,在对系统可观测性论证的基础上 ,设计了非线性滑模状态观测器 ,给出了单通道防抱制动系统基于滑移率的滑模控制算法 ,通过计算机仿真 ,验证了该控制算法的可行性和有效性 ,为设计具有高鲁棒性的防抱制动系统做了一定的理论探索和仿真工作     

基于计算机仿真的ABS开发平台研究

该文阐述了基于计算机仿真的制动防抱系统开发技术,详细介绍了基于计算机仿真的制动防抱系统开发的三个步骤,并且给出了各个阶段的试验方案;建立了双轴汽车的制动防抱系统通用仿真开发平台,该平台具有对各种车辆ABS开发的互换性,并且操作简易,灵活;为了模拟ABS在各种路面的制动状况,该平台设计出了路面跃变模块,可进行单一路面和跃变路面的制动防抱系统仿真试验。根据试验结果验证,模型准确可靠,可以用于下一步控制器的研究开发。     

随机路面激励下整车NVH有限元分析

针对应用刚体动力学方法不能得到驾驶员可以直接感知的振动加速度的缺陷,提出应用整车柔性体模型进行汽车随机路面平顺性分析的方法.对一种典型路面不平度数据进行处理并将得到的功率谱密度(Power Spectral Density,PSD)作为激励,建立整车有限元模型,通过试验模态验证该模型后进行传递函数分析;根据所得的激励和传递函数的结果计算得出汽车方向盘处的速度响应.该速度响应与随机路面平顺性试验一致性较好。     

3D road traffic situation simulation system

The 3D traffic situation simulation system combines the multibody based mathematical model of a vehicle, the multibody mathematical model of human body, the database of vehicle and human body data and the display subsystem. Together with the model of driving surface the system can be used to simulate and analyse vehicle and its occupant behaviour under different road conditions and different driving regimes. The result obtained this way can be used to investigate safety related parameters and optimise the driver–vehicle–road system regarding to arbitrary criteria (safety, comfort, speed, etc.). The results of simulations are available as numerical data as well as animations in virtual 3D environment.     

路面不平度采集系统设计

针对路面不平度的检测,开发了一套基于加速度传感器和C8051F单片机路面不平度采集系统。该采集系统的硬件主要包括传感器模块、信号调理模决、单片机模块和蓝牙无线通信模块。加速度传感器检测行驶车辆的悬架垂直加速度信号,并通过信号调理模块调整模拟信号的电压范围。单片机则对传感器采集的信号进行模数转换并通过蓝牙传送给上位机。编写了基于C#环境下的上位机采集控制和数据处理软件。经过连续运行测试证明,系统运行稳定,具备良好的实时性和可靠性,可应用于路面不平度检测。     

城市轨道车辆电力牵引实验台测控系统设计

介绍了一种城市轨道车辆电力牵引实验台,针对其多参数采集和实时控制的特点,设计了基于虚拟仪器的测控系统。系统以工业计算机为核心,采用LabVIEW语言编程,对牵引电机进行转速闭环控制,并采集转速量,实时计算相应的车辆运行速度和路段,从而使负载电机进行动态阻力加载。系统实验结果与实车测试数据的对比分析显示,该测控系统使牵引电机的启动阶段加速度保持1.03 m/s2,在电制动过程中,当直流母线电压达到设定阀值670 V时,再生制动向电阻制动实时切换,工作特性与实车测试数据基本一致。系统对于城市轨道车辆牵引和电制动特性方面的研究具有重要意义。     

卡尔曼滤波在桥梁健康监测系统中的应用研究

针对传统的桥梁位移测量方法的不足,提出了采用双轴加速度传感器进行桥梁位移测量的原理和方法,即利用双轴加速度传感器能同时敏感两个互相垂直的方向上的加速度,从而经过有效的信号处理可获得桥梁的振动位移;讨论了低频噪声对桥梁位移测量的影响;提出以卡尔曼滤波原理为基础的信号处理方法来提高测量精度,抑制噪声,并得到两个方向的位移信息;仿真结果表明了本滤波方法的有效性。     

Analytical dynamic impact study based on correlated road roughness

The dynamic behavior of multigirder bridges under heavy trucks is investigated based on correlated road surface roughness. Four prestressed concrete bridges with span lengths ranging from 9.14 to 42.67 m (30 to 140 ft) are modeled as grillage beam systems. 3D nonlinear mathematical models for typical trucks are developed based on weigh-in-motion measurement data. These data were collected at two stations located on interstate highway 75 and 95, respectively, for a period of one week. There are a total number of truck counts of 21,444 processed in this study. The longitudinal road surface roughness is generated as correlated random processes along the deck transverse direction. Based on the results from field measurements, the spatial coherence function of these roughness profiles is approximately taken as a constant. Analytical results indicate that (1) the mean values of dynamic impact factors induced by heavy trucks are generally less than the values specified by the American Association of State Highway and Transportation Officials Specifications; and (2) the impact factors generally increase with the coefficient of correlation of road surface roughness.     

Center of gravity height real-time estimation for lightweight vehicles using tire instant effective radius

Center of gravity (CG) height is an important parameter for lightweight vehicles (LWVs). Because of the inherently smaller weight and size, a LWV's CG height is more easily affected by loading conditions compared with conventional vehicles. This paper proposes a novel tire instant effective radius (TIER) method for real-time estimation of the CG height for LWVs. The method utilizes the mathematical correlation between the tire vertical load transfer that is proportional to the CG height, and the TIER variation. A Kalman filter based estimator is designed to simultaneously identify the vehicle CG height as well as the unknown nominal tire effective radius. To verify the performance of the proposed estimator, simulation results are first provided for several vehicles with different CG heights, and then road test results obtained on a lightweight electric ground vehicle (EGV) equipped with an advanced measurement system are given. Both simulation and experimental results show that the developed estimator is capable of providing an accurate estimation of the vehicle CG height in real-time.     

Nonlinear observer-based active control of ground vehicles with non negligible roll dynamics

In this paper we present an observer–based nonlinear controller for lateral and yaw velocity, for a vehicle in which the roll dynamics can not be neglected. The observer estimates the lateral velocity, and the roll position and velocity. This technique is based on measurements of the longitudinal and lateral accelerations, longitudinal velocity, yaw rate and steer angle, usually available in modern vehicles. The nonlinear observer ensures exponential convergence of the estimations. The test maneuvers, obtained with the full–vehicle CarSim model under different road adhesion conditions, have been used to check the controller performance, as well as its robustness with respect to parameter variations.