基于多目标粒子群优化算法的某轻型商用车操纵稳定性优化研究

针对某轻型商用车稳态回转时侧倾度偏大的问题对其悬架进行优化改进。基于ADAMS/car搭建整车多体动力学模型,通过前悬架反向平行轮跳试验、后悬架理论计算验证了悬架仿真模型的准确性。进行整车稳态回转工况和转向盘中间位置转向工况仿真分析,结果表明,车身侧倾度偏高。为实现操纵稳定性优化分析的流程自动化,提出了基于modeFRONTIER的联合仿真方法。以悬架设计参数为优化变量,以汽车的侧倾度与横摆角速度响应滞后时间为优化目标,采用拉丁超立方试验设计方法拟合得到混合代理模型,并结合多目标粒子群优化算法对悬架系统进行多目标优化,获得了悬架系统优化方案。优化结果显示,在不影响平顺性的前提下,汽车车身侧倾度降低了13.93%,横摆角速度响应滞后时间降低了2.75%,整车操纵稳定性得到了提升。     

Torsion beam axle system design with a multidisciplinary approach

This research proposes an automatic torsion beam axle optimization process with a multidisciplinary approach and generates the optimal torsion design parameters, such as thickness and shape. In order to construct an automatic analysis process, multidisciplinary analysis models, such as modal analysis, roll mode dynamic analysis, and fatigue analysis, were applied in batch mode. To understand the design space, a parametric study using the torsion beam thickness and shape was performed. Considering roll durability and K&C characteristics, the torsion beam axle could be optimized. For the automated design process, a PIDO tool called PIAnO was used. In conclusion, a reduction in the computer-aided simulation time was achieved, and the durability and K&C characteristics of the torsion beam were enhanced by optimizing the thickness and shape.     

扭转梁后桥性能仿真优化及试验分析

扭转梁后桥开发过程中,须按照从整车技术要求分解出的零部件技术规范进行设计,并借助CAE优化技术对零部件各性能进行优化。本文主要针对某型扭转梁后桥侧向力耐久疲劳和减振器力耐久疲劳工况进行优化分析,结构优化后耐久疲劳寿命提高。实物样件台架验证结果与优化仿真分析结果基本一致。     

某微型轿车后扭力梁式悬架K特性计算分析

为了获得横梁位置、扭力梁长度、初始定位参数这几个因素对整车性能的影响,本文建立了一种简化了的扭力梁式悬架模型,并根据这一模型计算出扭力梁式悬架的定位参数及侧倾中心高度。根据定位参数和侧倾中心高度的变化趋势来合理地选择扭力梁式悬架的设计参数。结果表明,横梁位于扭力梁中部时,定位参数匹配较好;扭力梁长度增加时对侧倾中心高度影响明显;初始外倾角对车辆性能的影响更明显。结论可以为扭力梁式悬架的设计计算提供参考。     

影响车辆转向瞬态响应特性的因素研究

利用ADAMS/CAR二次开发模块,建立了国产某小客车的整车多体系统动力学仿真模型。分析了车辆转向盘角阶跃输入和脉冲输入时的瞬态响应特性,并对相关的影响因素进行了预测分析,通过调整后轮侧倾刚度等参数,优化转向瞬态特性响应结果,经过样车的试验验证了优化结果。     

扭力梁式后悬架对不足转向性的影响分析

根据汽车操纵稳定性理论和悬架侧倾受力分析,较系统地阐述了扭力梁式后悬架对整车不足转向性的影响和改善措施。通过对前束和轴转向的控制,使后轴车轮侧偏角背离整车离心力方向,以提高整车的不足转向性。     

结合卡尔曼滤波器的车辆主动悬架轴距预瞄控制研究

利用轴距预瞄信息，即前后轮路面输入之关系，同时结合卡尔曼滤波器作为状态估计器，本文提出了一种算法用于车辆悬架控制律的设计，根据模拟结果，研究了算法的可行性，分析了卡尔曼滤波器对状态变量的估计精度，以及轴距预瞄控制对进一步改进车辆性能的潜力。     

增程式电动SUV行驶稳定性优化设计

结合某增程式电动SUV开发所面临的问题,通过理论分析、悬架K&C分析、整车操稳性分析、悬架系统K特性多目标优化等手段,在保证底盘零部件通用化的基础上,对后悬架K特性进行优化设计,提出优化方案。通过制作设计样车,并对设计样车进行主观评价,底盘性能问题得到很好地解决,为后续底盘性能提升奠定了良好基础。     

Design Optimization of a Rear Independent Suspension for the Korean Light Tactical Vehicle

Steering and suspension handle the direction of a vehicle according to the driver’s intentions and control the disturbance from the road surface while supporting the vehicle body. The static and dynamic characteristics of two systems are critical factors for the ride comfort and the directional stability. In the layout stage, the hard points of steering and suspension systems are determined. In the next design stage, the detailed design of the system, including gearboxes, springs, shock absorbers, and control links, is carried out. While the optimal hard points of a suspension are determined at the precedent design, interference with other peripheral components should be carefully examined in the detailed design process. In the case of the design point change should be made to avoid the interference, subsequent position and shape changes of the link mechanism are required. Therefore, there is a need to examine the optimization of suspension compliance characteristics with chassis design changes and the durability performance of the modified design. This study proposes an integrated analysis method for the design optimization and the durability evaluation of such optimized design specifications of the rear independent suspension for a military vehicle.     

扭转梁式半独立后悬架系统开发

在扭转梁式半独立后悬架系统开发时,需要设计师平衡各种利弊因素,通过优化方法来达到预先设定的性能.扭转梁的剪切中心、横梁截面、扭转刚度以及悬架运动特性的确定是这种类型悬架设计的关键点.     

Aerodynamic design optimization of rear body shapes of a sedan for drag reduction

This study proposes an aerodynamically optimized outer shape of a sedan by using an Artificial Neural Network (ANN), which focused on modifying the rear body shapes of the sedan. To determine the optimization variables, the unsteady flow field around the sedan driving at very fast speeds was analyzed by CFD simulation, and fluctuations of the drag coefficient (C _D ) and pressure around the car were calculated. After consideration of the baseline result of CFD, 6 local parts from the end of the sedan were chosen as the design variables for optimization. Moreover, an ANN approximation model was established with 64 experimental points generated by the D-optimal methodology. As a result, an aerodynamically optimized shape for the rear end of the sedan in which the aerodynamic performance is improved by about 5.64% when compared to the baseline vehicle is proposed. Finally, it is expected that within the accepted range of shape modifications for a rear body, the aerodynamic performance of a sedan can be enhanced so that the fuel efficiency of the sedan can be improved. The YF SONATA, a sedan manufactured by Hyundai Motors Corporate, played a major role in this research as the baseline vehicle.     

Robust design optimization of the dynamic responses of a tracked vehicle system

This paper presents the robust design optimization of the dynamic responses of a heavy military tracked vehicle system. The tracked vehicle model addressed in this study has 954 degrees of freedom and consists of 189 bodies in total: 37 bodies for the chassis, such as sprockets, road wheels, road arms, etc.; 76 track link bodies for each track subsystem; 36 revolute joints; and 152 bushing elements. The design objectives were to minimize the maximum vertical acceleration of the hull and its variance while satisfying the wheel travel constraints for torsion bars and the hydro-pneumatic suspension units within ±1σ ranges. To avoid the difficulty of the design sensitivity analysis and to overcome the numerical noise, a progressive meta-model technique was employed in the optimization process. First, space-filling methods were used to determine the minimum number of sample points. Second, the simultaneous kriging method was used to construct the initial meta-models, and the augmented Lagrange multiplier (ALM) method was then used to solve the robust design problems of the meta-models. Third, the new design results were added to the analysis results for the initial sample points, and the meta-models were updated automatically. Next, the optimizer resolved the robust design problems of the updated meta-models. These processes were repeated until the convergence tolerances were satisfied. The robust design optimization of the tracked vehicle system, with 11 random design variables, was solved in only 26 analyses, including 12 analyses for the initial meta-models and 14 analyses added during the iterative optimization process.     

基于ADAMS／Insight的多连杆后悬架系统优化分析

在对某型轿车多连杆后悬架系统建立ADAMS多体动力学模型基础上,对该悬架系统进行了仿真分析,分析了轮跳对后轮定位参数的影响,并结合ADAMS／Insight模块对该悬架部分硬点的位置进行了DOE优化。优化结果表明,对该悬架系统所做的优化设计是正确有效的,改善了该悬架系统的运动特性。     

概念设计阶段扭转梁式后悬架建模方法研究

在ADAMS软件中采用分别生成后桥各零件柔性体模型后再进行装配的建模方法构建了后桥总成的柔性体模型,进而构建了全参数化扭转梁式悬架模型。通过对该悬架模型进行仿真分析,获取了车轮定位角、悬架侧倾角刚度等悬架关键特性参数的变化曲线。该曲线与利用K＆C试验台得到的该汽车后悬架相应特性参数的试验曲线进行比较表明,仿真结果和试验结果吻台较好．     

双横臂独立悬架ADAMS建模及运动特性分析

利用ADAMS建立了某轻型车完整的双横臂独立悬架运动学仿真模型,为反映车辆的真实行驶工况,对左、右车轮测试平台分别创建了随机激励。通过仿真分析,揭示了运动特性参数在悬架运动过程中的变化规律,并对原导向机构存在的问题进行了优化计算。结果表明,前轮定位参数在优化前、后的变化量较小,均在设计要求的范围内;轮距和前轮侧向滑移量的变化较大,优化后二者都在理想的范围内变动,达到了预期优化目标。     

Rollover mitigation for a heavy commercial vehicle

A heavy commercial vehicle has a high probability of rollover because it is usually loaded heavily and thus has a high center of gravity. An anti-roll bar is efficient for rollover mitigation, but it can cause poor ride comfort when the roll stiffness is excessively high. Therefore, active roll control (ARC) systems have been developed to optimally control the roll state of a vehicle while maintaining ride comfort. Previously developed ARC systems have some disadvantages, such as cost, complexity, power consumption, and weight. In this study, an ARC-based rear air suspension for a heavy commercial vehicle, which does not require additional power for control, was designed and manufactured. The rollover index-based vehicle rollover mitigation control scheme was used for the ARC system. Multi-body dynamic models of the suspension subsystem and the full vehicle were used to design the rear air suspension and the ARC system. The reference rollover index was tuned through lab tests. Field tests, such as steady state cornering tests and step steer tests, demonstrated that the roll response characteristics in the steady state and transient state were improved.     

Robust design optimization of suspension system by using target cascading method

This study presents the robust design optimization process of suspension system for improving vehicle dynamic performance (ride comfort, handling stability). The proposed design method is so called target cascading method where the design target of the system is cascaded from a vehicle level to a suspension system level. To formalize the proposed method in the view of design process, the design problem structure of suspension system is defined as a (hierarchical) multilevel design optimization, and the design problem for each level is solved using the robust design optimization technique based on a meta-model. Then, In order to verify the proposed design concept, it designed suspension system. For the vehicle level, 44 random variables with 3% of coefficient of variance (COV) were selected and the proposed design process solved the problem by using only 88 exact analyses that included 49 analyses for the initial meta-model and 39 analyses for SAO. For the suspension level, 54 random variables with 10% of COV were selected and the optimal designs solved the problem by using only 168 exact analyses for the front suspension system. Furthermore, 73 random variables with 10% of COV were selected and optimal designs solved the problem by using only 252 exact analyses for the rear suspension system. In order to compare the vehicle dynamic performance between the optimal design model and the initial design model, the ride comfort and the handling stability was analyzed and found to be improved by 16% and by 37%, respectively. This result proves that the suggested design method of suspension system is effective and systematic.     

某越野车前悬架优化研究

前悬架参数是汽车的重要参数,提出了虚拟试验优化设计方法以确定这些参数。根据多刚体动力学原理,建立前悬架和整车虚拟样机。在ADAMS／Car中进行了两侧车轮同向跳动试验、低速回正性试验、高速回正性试验。在试验中利用ADAMS／Insight对前悬架参数进行优化,对比优化前后试验结果,证明这种设计方法可以令参数选择更加合理,同时缩短设计开发周期,减少成本。     

扭转梁后悬架C特性对转向特性的影响分析

为分析扭转梁C特性对稳态转向性能的影响,文章以模态综合法建立了某乘用车扭转梁后悬柔性模型,对建立的原型车进行侧向力C特性仿真,与对标车进行对比发现仿真与试验值存大较大差异,且侧向力前束特性存在较大的过度转向趋势.通过优化安装衬套的刚度使得原型车与试验结果吻合,最后对整车进行稳态回转仿真发现,负的前束侧向力特性不利于转向,优化后的模型提高了整车不足转向.     

某轿跑SUV提升转向响应的硬点优化仿真与验证

针对某SUV车型的前悬架响应慢,进行了前悬架的仿真优化分析,通过抬高转向器安装硬点位置可以优化前悬架侧倾转向和平跳转向的特性,减小不足转向度,提升整车响应特性,然后进行客观测试来对比指标变化,最后得出结论通过加高转向器安装硬点可以提升整车转向响应。