在线摩擦学设计知识获取方法的研究

采用故障诊断和动力学分析相结合的方法，研究了轴承—转子系统摩擦学设计知识获取方法，提出了动力学性能神经网络计算方法，实现了在线动力学分析，为知识获取提供轴承—转子系统实时性能参数。利用灵敏度矩阵可以得到系统运行、维护和设计的改进方案。实例证明：该方法是可行有效的。     

100%低地板有轨电车动力学性能分析

运用多体动力学分析软件SIMPACK建立了一种采用小轮径传统轮对的100%低地板有轨电车的动力学模型,并分析了该模型的运行稳定性、运行平稳性及曲线通过性等动力学性能。结果表明:该100%低地板有轨电车具有良好的运行稳定性和直线运行平稳性,并能安全通过城市小半径曲线。     

基于空气动力学的土工离心机 造型优化设计

土工离心机的空气动力学性能直接影响其在亚声速运行状态下运行的稳定性。以降低离心机高速运行时的空气阻力为优化目标,对造型进行空气动力学优化设计探索。在使用参数化建模方法建立的离心机简化模型的基础上,根据阻塞效应反求方法定义计算流场域。采用计算流体力学方法对土工离心机以及周围流场进行空气动力学分析,分析结果为优化提供了理论支持,对离心机的空气动力学性能敏感位置进行了造型优化,对设计变量与性能变化进行相关性分析。结果表明空气阻力伴随关键位置造型的变化呈现单调性变化,优化后的土工离心机空气动力学性能提升效果显著。     

过山车虚拟样机的建模与动态仿真分析

研究基于虚拟样机技术的过山车动力学仿真分析。解决了虚拟样机建模的关键技术问题，例如，过山车轨道和车辆建模、车辆与轨道间的约束，施加摩擦力、根据测控信号自动施加车辆制动力等，建立了过山车系统虚拟样机。利用ADAMS软件对过山车虚拟样机进行动力学仿真分析，研究了运行过程中车辆位置、速度、加速度和受力的变化情况，获得了过山车的各种动态性能，为过山车设计和性能评价提供了一种新手段。     

100%低地板有轨电车动力学性能研究

利用SIMPACK多体动力学软件建立了100%低地板有轨电车的动力学模型,并对其运行稳定性、平稳性和曲线通过性能进行了动力学仿真计算。分析结果表明,该车具有良好的稳定性、平稳性和小半径曲线通过能力。     

考虑随机参数的高速列车动力学分析

建立高速列车车辆系统非线性动力学仿真模型,考虑悬挂刚度和阻尼、轮轨匹配参数、轮轨界面参数、轨道不平顺和载重的随机性,应用数值仿真研究高速列车动力学性能的随机统计特征。分析随机参数确定方法、动力学仿真工况数量和计算结果后处理方法,并与试验结果进行对比验证。计算结果表明,与常规动力学分析相比,考虑随机因素的动力学方法可以得到动力学指标的分布特性,能够考虑到多种参数随机变化对动力学性能的综合影响。常规动力学计算结果是考虑随机因素的特例,能代表车辆动力学性能的普遍规律,但不能掌握动力学指标的变化域和分布规律。考虑随机因素的动力学方法可用于高速列车动力学性能预测、动力学参数优化和异常振动分析等领域,能更加真实、全面反映车辆动力学性能,优化出的悬挂参数具有更广泛的线路运行适应性。     

铁道车辆动力学模型设计及优化分析

采用多体动力学软件SIMPACK建立铁道车辆动力学模型,并对其进行优化分析,调用SIMPACK计算不同车辆悬挂参数下的车辆动力学性能,包括安全性、稳定性、舒适性等指标。采用脱轨系数、倾覆系数、轮轨横向力评价指标对车辆运行安全性进行评定,优化分析采用最优试验设计方法构建了近似模型,经过优化计算,车辆的动力学综合性能提高了30%以上,每一个动力学指标都有不同程度的提高。     

基于非线性接触理论的行星传动系统

基于非线性接触理论和多体动力学理论,建立了某行星齿轮传动系统的多体动力学模型,对实际运行工况下的动态性能进行仿真研究,获取了轮齿的实时动态接触力和关键部件的动态等效应力,仿真结果与理论分析吻合较好。研究表明,采用刚柔耦合多体动力学模型研究行星齿轮传动系统的动态性能更加符合实际,分析结果合理、可靠。     

直线电机地铁车辆的车轮磨耗特性及动力学性能试验研究

对国内某直线电机地铁线路轴箱内外置列车的车轮磨耗规律和动力学性能进行了现场调查、特征对比以及形成机理的理论研究。通过两种车型不同镟后运行里程的车轮磨耗测试,分析了两种轴箱布置方式车辆的车轮磨耗形式、分布区域及磨耗速率的演变规律。通过正线运行动力学测试,对两种车型镟轮前后的运行平稳性和稳定性进行了对比研究。研究结果表明,镟后6万公里前,轴箱内置车辆的车轮踏面磨耗小于轴箱外置车辆,镟后里程达到10万公里以上时,两种车型的磨耗量相当。轴箱外置车辆的运行平稳性和稳定性优于轴箱内置车辆,同时对轮轨状态的适应性更好。基于两种车型的车辆结构特征及其与动力学性能的相关分析,揭示了两种车型车轮磨耗和动力学性能差异的内在机理,明确了两种车型的动力学特性,并提出了两种车型的优化设计建议。     

列车纵向冲动仿真建模的研究

列车纵向动力学性能是影响列车运行质量和运行安全的重要因素。制动工况变换则是导致列车冲动的主要原因。针对列车在制动工况下的纵向动力学分析，详细论述了列车纵向冲动仿真建模的过程。在Matlab／Simulink仿真模块中，可以计算出每节车体的加速度及车钩力大小，为进一步分析并减轻列车纵向冲动提供了理论基础。     

Kinematics and Path Following Control of an Articulated Drum Roller

Automatic navigation of an articulated drum roller, which is an articulated steering type vehicle widely used in the construction industry, is highly expected for operation cost reduction and improvement of work efficiency. In order to achieve the path following control,considering that its steering system is articulated steering and two frames are articulated by an active revolute joint, a kinematic model and an error dynamic state-space equation of an articulated drum roller are proposed. Besides, a statefeedback control law based on Lyapunov stability theory is also designed, which can be proved to achieve the purpose of control by the analysis of stability. What's more, to evaluate the performance of the proposed method, simulation under the MATLAB/Simulink and experiments using positioning algorithm and errors correction at the uneven construction site are performed, with initial displacement error(-1.5 m), heading error(-0.11 rad) and steering angle(-0.19 rad). Finally, simulation and experimental results show that the errors and steering angle can decrease gradually, and converge to zero with time.Meanwhile, the control input is not saturated. An articulated drum roller can lock into a desired path with the proposed method in uneven fields.     

基于AMESim和ADAMS铰接车全液压转向系统分析

铰接式车辆因其机动性好、适应性强且生产效率高而被广泛采用,而其不足之处在于转向时横向稳定性较差,翻车事故时有发生,为解决此问题,应用虚拟样机技术对此类车辆的转向过程进行分析。基于液压系统与多体动力学系统的联合仿真,在ADAMS中建立六轮电驱动铰接车的多体动力学模型,在AMESim中搭建其全液压转向系统模型,以实现铰接车的转向过程。 通过PID控制转向油缸的油量使其铰接角维持一个定值,对铰接车的行驶转向进行分析,并考虑车速对铰接车稳态转向的影响。获得铰接车行驶转向下各个轮胎的运动轨迹,各个轮胎所受侧向力、纵向力及垂直力随时间的变化曲线和转向油缸中活塞杆的受力。结果表明:随着行驶速度的增大,铰接车的外侧各个轮胎的受力均明显的增大;且铰接车的转向半径也随着增大;全液压转向系统具有明显的不足转向特性。     

铰接式自卸车悬架系统建模与仿真

在分析某铰接式自卸车橡胶悬架结构拓扑构型的基础上,运用多刚体动力学理论,基于ADAMS平台建立了该车橡胶悬架系统及整车的非线性数字化虚拟样机。在不同的等级路面下,以不同载荷和车速对模型进行了动力学仿真分析。并与实验结果进行对比,评价了该铰接式自卸车多刚体模型的有效性。     

轮式铰接车辆的动力学耦合模型研究

提出了轮式铰接车辆的动力学耦合模型,并且给出了此耦合模型的具体形式,这为正确把握轮式铰接车辆在不平路面行驶时的运动状况提供了理论依据,同时为最终实现对轮式铰接车辆的主动悬架控制提供了一定的理论基础.     

基于MATLAB铰接式车辆原地转向特性的研究

基于铰接式车辆原地转向特性,建立了铰接式车辆原地转向运动学模型,同时建立了装载机原地转向力学模型,分别对单桥驱动、双桥驱动和转向力学模型阻力矩进行了计算,得到了前、后桥轮荷。运用MATLAB软件对满载原地转向阻力矩和轮荷进行了计算和仿真,为铰接车辆转向系统设计和校验提供了依据。     

Design of a Preview Controller for Articulated Heavy Vehicles

The paper presents a preview controller design for ATS （active trailer steering） systems to improve high-speed stability of AHVs （articulated heavy vehicles）. An AHV consists of a towing unit, namely tractor or truck, and one or more towed units which called trailers. Individual units are connected to one another at articulated joints by mechanical couplings. Due to the multi-unit configurations, AHVs exhibit unique unstable motion modes, including jack-knifing, trailer swing and rollover. These unstable motion modes are the leading cause of highway accidents. To prevent these unstable motion modes, the preview controller, namely the LPDP （lateral position deviation preview） controller, is proposed. For a truck/full-trailer combination, the LPDP controller is designed to control the steering of the front and rear axle wheels of the trailing unit. The calculation of the corrective steering angle of the trailer front axle wheels is based on the preview information of the lateral position deviation of the trajectory of the axle center from that of the truck front axle center. Similarly, the steering angle of the trailer rear axle wheels is calculated by using the lateral position deviation of the trajectory of the axle center from that of the truck front axle. To perform closed-loop dynamic simulations and evaluate the vehicle performance measure, a driver model is introduced and it ＇derives＇ the AHV model based on well-defined testing specifications. The proposed preview control scheme in the continuous time domain is developed by using the LQR （linear quadratic regular） technique. The closed-loop simulation results indicate that the performance of the AHV with the LPDP controller is improved by decreasing rearward amplification ratio from the baseline value of 1.28 to 0.98 and reducing transient off-tracking by 95.03%. The proposed LPDP control algorithm provides an alternative method for the design optimization of AHVs with ATS systems.     

煤矿井下运煤车转向机构优化设计

以井下运煤车的转向机构为研究对泉,分析了影响铰接车转向机构转向性能的各个因素,以及它们的影响趋势.同时建立了以综合转向性能最优为目标的优化设计数学模型.仿真结果表明:与原转向机构相比,优化后的转向机构的转向性能更好.     

机动车短时四轮全驱动前后独立轴输出分动器设计应用

通过改变机动车的驱动模式可以适应不同的路况,安全可靠而且节能,其方法是将机动车发动机发出的动力经变速器变速后再经分动装置分动,从而实现机动车能够在三种模式行驶.经过在折腰式拖拉机的改造实践应用证明,该研发装置安全可靠省油,而且改造成本低,有着很高推广应用价值和经济意义.     

Characterisation of optimal human driver model and stability of a tractor-semitrailer vehicle system with time delay

In this paper, a vehicle/driver close-loop system is studied in order to characterise the inherent model parameters of an optimal human controller for a regulation task (e.g. stabilisation after a wind gust) in articulated vehicle motions. The tractor-semitrailer vehicle model consists of two articulated rigid bodies moving on a horizontal plane with a constant forward speed. The driver establishes his steering control through a time-delayed feedback from current vehicle states with respect to the desired motion. Identification of driver model parameters is achieved through an optimal control approach. The stability of the delayed dynamical system is also studied using a numerical method by computing the eigenvalues near the imaginary axis.     

The articulated vehicle dynamic analysis using the AWS (All Wheel Steering) ECU (Electronic Control Unit) test

An AWS (all-wheel-steering) system is applied to the articulated vehicle to satisfy the required steering performance. AWS ECU (electronic control unit) controls the hydraulic actuator according to vehicle driving environment, such as driver steering angle, articulating angle, and vehicle velocity. In this paper, the test platform devloped for the AWS ECU black box test in an HIL( hardware in the loop) environment is explained. Using the developed test platform, the control algorithm of the AWS ECU can be evaluated under the virtual driving condition of the articulated vehicle. Also, the maneuver of the vehicle is investigated by using the developed AWS ECU test. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Sooho Lee received a B.S. degree in Mechanical Engineering from Ajou University in 2003. He then went on to receive his M.S. degree from Ajou University in 2005. Mr. Lee is currently a Ph.D student in the School of Mechanical Engineering at Ajou University in Suwon, Korea. His research interests are in the area of dynamics, vehicle dynamics, control and HILS ( hardware in the loop simulation).