基于Adams/Car的客车前悬架模型的仿真分析

利用Adams/Car建立钢板弹簧非独立悬架模型,并进行双轮平行跳动仿真试验.仿真试验得到外倾角、车轮前束角、主销内倾角与车轮跳动行程的关系,前束角变化很小,为0.01°/100 mm;车轮外倾角变化很小,为0.019°/100 mm.分析得出的外倾角、车轮前束角和主销内倾角均在合理的取值范围内,该悬架系统具有良好的操作稳定性.     

微型多功能车双横臂独立悬架优化设计

微型多功能车双横臂前独立悬架设计的好坏对车轮跳动时前轮前束和轮距的变化有很大的影响.运用虚拟样机技术,在ADAMS环境下建立了微型多功能车SX2526的前双横臂独立悬架刚-柔耦合模型,进行了运动学仿真.在此基础上运用"主要目标法"进行了以前轮前束和轮距变化为目标的悬架多目标优化设计,得到优化后的悬架空间结构的几何形式.经过悬架优化设计,前轮前束和轮距随车轮跳动时的变化范围大大减小.极大地改善了微型多功能车行驶过程中的操作稳定性.     

橡胶衬套刚度对悬架运动学的影响

橡胶衬套在现代汽车上的广泛应用对整车操纵稳定性和平顺性造成了很大的影响。为减少由于橡胶衬套引起的悬架运动学特性的变化,论文在ADAMS/View中建立了包含有橡胶衬套的麦弗逊悬架。通过ADAMS/Insight对各个衬套的刚度进行灵敏度分析,选取刚度变化对车轮定位参数影响较大的衬套刚度作为优化变量,以车轮前束角、外倾角和轮距作为优化目标。在Matlab中运用遗传算法调用ADAMS中的脚本文件,对橡胶衬套进行优化得到最优刚度值。经比较分析,优化后悬架定位参数变化范围减小。由此通过优化橡胶衬套刚度改善了悬架运动学特性。     

混合空气悬架系统侧倾仿真

为了研究某混合空气悬架的侧倾特性,在ADAMS/CAR中建立了该悬架系统刚柔体耦合的动力学模型。首先确定该型混合空气悬架的常用车轮跳动行程和台架侧倾仿真实验方法,然后确定了安装横向稳定杆和拆除横向稳定杆两种系统状态作为仿真工况,最后使用ADAMS/CAR,完成了该悬架系统在常用车轮跳动行程范围的台架侧倾仿真,得出了悬架侧倾刚度与车轮跳动关系曲线,探讨了横向稳定杆对该型悬架侧倾稳定性的影响结果。这个台架侧倾仿真模型可以用于确定该混合空气悬架系统在不同系统状态下的侧倾特性,校验悬架系统设计。     

双横臂独立悬架运动特性分析与优化

研究双横臂独立悬架性能优化问题,在车辆运动过程中,由于车轮与车身之间的相对位置发生变化,造成车轮定位参数的变动过大,加剧轮胎磨损,并降低悬架的性能.针对上述问题,通过对悬架系统简化处理,建立悬架运动学分析理论模型.为改进悬架性能,采用统一目标法,将多目标优化转化为单目标优化,实现在ADAMS/Insight中对悬架结构参数进行优化设计.利用ADAMS/Car软件建立了双横臂独立悬架动力学仿真模型并进行仿真,结果表明优化后车轮定位参数和轮距的变化量均减小,更趋于合理的取值范围,悬架性能得到改善.     

汽车转向机构仿真及优化设计

研究汽车转向机构优化设计问题,传统转向机构设计忽略转向机构与悬架干涉,造成实际工况下前轮定位参数变化过大,导致操纵稳定性下降.为了提高实际工况下转向性能,针对原地转向及车轮跳动工况,根据阿克曼转角几何原理及前轮定位参数变化规律,采用多目标优化方法建立复合加权惩罚函数进行优化设计.并在建立优化模型时引入试验设计方法(DOE)进行设计变量筛选.应用ADAMS软件建立某车前悬架总成动力学模型进行仿真优化.仿真结果表明,优化后模型更好地满足了阿克曼转角几何原理,转向机构与悬架更加匹配,验证了改进方法在转向机构优化设计中的实用性与优越性.     

前馈神经网络在汽车悬架设计中的应用*

提出采用GABP贝叶斯算法来建立悬架运动学分析近似模型。该算法是一种新型前馈神经网络训练算法,它以提高网络的泛化性能为主旨,其训练目标在于获取对应于后验分布最大值的权值向量。以双横臂式前独立悬架为例,采用GABP贝叶斯算法建立了以车轮接地点侧向最大滑移量为输出的运动学分析近似模型,并与LMBP算法、多项式回归和广义回归神经网络这三种方法进行了比较。结果表明,基于GABP贝叶斯算法的近似模型的预测精度明显高于其他几种模型,并且受随机因素的影响很小。     

某轿车的前双横臂独立悬架优化设计

研究某一轿车双横臂独立悬架性能的优化问题,解决前轮定位参数在汽车行驶过程中变化过大而引起的轮胎磨损的加剧以及悬架性能的降低的问题.针对上述问题,在ADAMS/Car上建立了车双横臂独立悬架的动力学模型,运用Insight模块进行灵敏度分析,选取灵敏度较大的硬点参数作为设计变量,建立车轮定位参数在轮跳过程中的最大变化量的响应面近似模型.然后运用差分进化算法与非支配遗传算法的混合多目标算法(简称DE-NSGAII算法)对目标函数进行优化求解.结果表明,优化后的车轮定位参数在车轮跳动过程中的变化量明显减小,悬架的性能得到改善,为悬架的优化设计提供了依据.     

基于Adams/Car的汽车前悬架仿真分析及优化设计

针对某车型的麦弗逊前悬架系统,用车辆多体动力学仿真软件Adams/Car建立该悬架的虚拟样机模型,对其进行双轮同向跳动激振仿真分析,并综合评价该悬架的车轮定位参数、主销后倾拖距和转向角随轮跳的响应特性.在仿真分析的基础上,针对不合理的结构设计参数,利用Adams/Insight模块进行基于设计变量灵敏度分析的优化设计.优化后的悬架参数能很好地满足设计要求,从而达到提高该悬架系统整体性能的目的.     

电子样机技术DMU在汽车悬架运动机构中的应用与研究

本文对汽车的不等臂式双横臂独立悬架的运动特点进行了分析，并应用CATIA软件的Part Design模块，建立了汽车悬架的简化模型；然后应用电子样机模块DMU对悬架的运动学模型进行了动态仿真分析，创建了关键零部件的包络体，这为下一步汽车轮罩的装配设计提供了参考和依据。     

Robust impedance control of a hydraulic suspension system

A novel robust impedance control approach is developed to control dynamic behavior of a vehicle subject to road disturbances. This behavior is predetermined as an impedance rule to achieve passenger comfort and vehicle handling by the use of a hydraulically actuated suspension system. Impedance control law is simple, free of model and efficient to apply for a broad range of road conditions. Moreover, it relates comfort to handling. This control approach can provide a desired comfort when passing a bump, and both desired comfort and handling after passing a bump. Robust position and force controls are used to implement the robust impedance control with the presence of uncertainties. A transformed proportional–integral–derivative control is proposed to perform the robust control. The system stability is analyzed and analytical results are confirmed by simulations. A quarter‐car model of suspension system and a nonlinear model of hydraulic actuator are used to simulate the control system. Copyright © 2009 John Wiley & Sons, Ltd.     

Fast approximate clearance evaluation for rovers with articulated suspension systems

We present a light‐weight body‐terrain clearance evaluation algorithm for the automated path planning of NASA's Mars 2020 rover. Extraterrestrial path planning is challenging due to the combination of terrain roughness and severe limitation in computational resources. Path planning on cluttered and/or uneven terrains requires repeated safety checks on all the candidate paths at a small interval. Predicting the future rover state requires simulating the vehicle settling on the terrain, which involves an inverse‐kinematics problem with iterative nonlinear optimization under geometric constraints. However, such expensive computation is intractable for slow spacecraft computers, such as RAD750, which is used by the Curiosity Mars rover and upcoming Mars 2020 rover. We propose the approximate clearance evaluation (ACE) algorithm, which obtains conservative bounds on vehicle clearance, attitude, and suspension angles without iterative computation. It obtains those bounds by estimating the lowest and highest heights that each wheel may reach given the underlying terrain, and calculating the worst‐case vehicle configuration associated with those extreme wheel heights. The bounds are guaranteed to be conservative, hence ensuring vehicle safety during autonomous navigation. ACE is planned to be used as part of the new onboard path planner of the Mars 2020 rover. This paper describes the algorithm in detail and validates our claim of conservatism and fast computation through experiments.     

Modelling of Torsion Beam Rear Suspension by Using Multibody Method

The multibody systems analysis has become one of the main simulation techniques to calculate the elasto-kinematics characteristics of a car suspension under wheel loads or to realize complex full vehicle models in order to predict the handling performances or the NVH quality. The modelling of torsion beam rear suspensions—widely adopted in cars belonging to B or C class—presents some problems arising from the structural behaviour of this component. A linear method based on component mode synthesis was used to represent the flexible torsion beam within the multibody model. This kind of approach was compared with a non-linear FE analysis. The elasto-kinematics analysis of the suspension was performed by using SIMPACK multibody code. The main suspension parameters (toe angle, camber angle, wheelbase and track variation) were calculated by changing wheel travel and loads. Static analyses, involving great displacements, were performed and a different number of modes were considered in the modal condensation of the torsion beam. The results of multibody simulations were compared with those obtained from a non-linear FE model. Different stiffness values of the bushings that connect the torsion beam to the vehicle chassis were taken into account.     

Reconfiguration Planning for a Robotic Vehicle with Actively Articulated Suspension in Obstacle Terrain during Straight Motion

In this paper, an actively articulated suspension (AAS) reconfiguration method is proposed for a robotic vehicle with AAS to negotiate an obstacle during straight motion. Proposed method includes AAS locomotion for the locomotion with the AAS and a calculation method that is independent to the terrain model for posture control using the AAS reconfiguration. Using simulations, it was verified that the proposed method can reconfigure the AAS for a robotic vehicle to have the desired position and posture to negotiate an obstacle. The errors of height and orientation can be reduced while wheel driving on rough terrain. Also, the robot can maintain a minimum static stability angle over 0.6?rad. When observing the obstacle negotiation procedure using the AAS reconfiguration including the proposed locomotion, it was found that the robot can conduct a high-level command successfully using the proposed method. The robot can negotiate an obstacle with a height of 71% of its usable length and can maintain the minimum static stability over 0.3?rad. Also, the robot can manage terrain uncertainty using the proposed AAS reconfiguration method.     

四轮转向车辆转向解耦的双点跟踪控制

针对四轮转向(4WS)无人车辆路径跟踪中的过约束问题, 本文提出一种前后轮转向解耦的双点跟踪控制策略. 建立4WS车辆单轨运动学模型, 约束前后轮转向角速度, 规划曲率连续的回旋曲线参考位姿序列, 将其解耦为前后轴中心的双点参考轨迹; 以前后轮中心点为控制点, 采用非线性反馈控制的预瞄方法分别获得转向控制率, 双点跟踪误差指数收敛于0. 仿真和实车验证结果表明, 所提出的双点跟踪控制策略横向误差标准差减少0.2 m, 横摆角误差标准差减小3.0?, 具有更大的前后轮转角控制域和较高的跟踪精度     

橡胶衬套对后扭梁悬架性能的影响分析

在Adams/Car中建立后扭梁悬架模型,通过试验设计方法找出橡胶衬套各项刚度对悬架性能影响的贡献率,得出外倾角、前束角、悬架侧倾刚度及侧倾中心随衬套刚度的变化规律,最后选取影响悬架性能最大的刚度参数作为变量因子,对不同衬套刚度取不同的比例因子,通过Adams/Insight完成优化设计分析,并确定优化后的衬套刚度值.     

高速铁道车辆悬挂系统参数化建模、优化与仿真分析

为了协调高速铁道车辆的运动稳定性与曲线通过性能之间的矛盾,本文采用多目标优化方法对一种高速铁道车辆的关键悬挂参数进行了优化处理.采用多体动力学技术建立了某型高速铁道车辆62个自由度的动力学模型,模型考虑了轮轨接触几何非线性、轮轨蠕滑非线性和阻尼非线性等.采用ADAMS-Matlab联合仿真对车辆悬挂系统进行参数化改造,使弹簧刚度和阻尼系数均可调.采用基于遗传算法的多目标优化方法对悬挂参数进行优化,使车辆模型能同时满足3种动力学指标.对比优化前后模型的动力学性能可以发现:模型的运动稳定性和曲线通过性能得到显著提高,虽然运行平稳性有小幅降低,但仍能保持在优良的工作状态.