Optimization of suspension system of heavy off-road vehicle for stability enhancement using integrated anti-roll bar and coiling spring mechanism

Short suspension system has an indispensable effect on vehicle handling and ride,so,optimization of vehicle suspension system is one of the most effective methods,which could considerably enhance the vehicle stability and controllability.Motion control,stability maintenance and ride comfort improvement are fundamental issues in design of suspension system of off-road vehicles.In this work,a dependent suspension system mostly used in off-road vehicles is modeled using Trucksim software.Then,geometric parameters of suspension system are optimized using integrated anti-roll bar and coiling spring in a way that ride comfort,handling and stability of vehicle are improved.The simulation results of suspension system and variations of geometric parameters due to road roughness and different steering angles are presented in Trucksim and effects of optimization of suspension system during various driving maneuvers in both optimized and un-optimized conditions are compared.The simulation results indicate that the type of suspension system and geometric parameters have significant effect on vehicle performance.

Method for secondary spring load equalization of railway vehicles with two-stage spring suspension: Modeling and optimal regulation

To ensure running safety,the secondary spring loads of railway vehicles must be well equalized.Due to the coupling interactive effects of these hyper static suspended structures,the equalization adjustment through shimming procedure is quite complex.Therefore,an effective and reliable method in application is developed in this paper.Firstly,the best regulation of spring load is solved based on a mechanical model of the secondary suspension system,providing a target for actual adjustment.To reveal the relationship between secondary spring load distribution and shim quantity sequence,a forecasting model is constructed and then modified experimentally with consideration of car body’s elastic deformation.Further,a gradient-based algorithm with a momentum operation is proposed for the load optimization.Effectiveness of the whole method has been verified on a test rig.It is experimentally confirmed that this research provides an important basis for achieving an optimal regulation of spring load distribution for multiple types of railway vehicles.

Analysis of the Material Properties of Vehicle Suspension Coil Spring

The suspension coil spring is one of the most important components in a vehicle suspension system. Its primary function is to absorb the vibrational shocks that are occasioned by irregular road surface to provide the vehicle with stability and ride comfort. The main objective of this study is to design a suspension coil spring made of structural steel for light duty vehicles with the aim of weight and cost reduction. This study was motivated by the government of Ghana’s actions to industrialise the automotive sector of the country through government policies and programs. The study made use of high carbon steel and low carbon steel as the control materials and structural steel as the implementing material. This was done to determine the suitability of structural steel for vehicle suspension coil spring. The study analysed parameters such as total deformation, equivalent Von Mises stress, maximum shear stress, and safety factor in the static structural analysis. The fatigue analysis also analysed parameters such as fatigue life and fatigue alternating stress. The results of the study revealed that the suspension spring made of structural steel has superior properties against all the parameters set for this study apart from deformation. The two control materials that are known for suspension coil spring design and manufacture have better properties to withstand deformation than the implementing material.

MULTI-AXLE VEHICLE STABILITY BASED ON WHOLE VEHICLE MODEL

From the analysis of experiment data of the multi-axle vehicle chassis searching process, it is less accurate to predict multi-axle vehicle dynamic characteristic with simplified two-axle vehicle model. So it is important to find out a more effective modeling method in the study of multi-vehicle stability. In the development of heat transfer fluid（HTF） six-axle vehicle, a whole vehicle multi-body dynamic model is built through collaborate flowchart using Teamcenter Engineering, UG NX3 and MSC.Adams. The modeling method of connected hydragas spring suspension is validated by running test results. Based on this whole vehicle model, a kinematical analysis of suspension is implemented to achieve optimized suspension geometry parameters according to the stable requirement. Then, different handling simulations are carried out with regard to various tire characteristics, driving con- figurations, and equipments. According to the evaluation of whole vehicle handling characteristic, some design rules are summarized to improve the stability of multi-axle vehicle.

Simulation Research on an Active Anti-Roll System for an Air Spring Passenger Car

To reduce the roll movement of an air spring passenger car, an active anti-roll system is developed, which is constructed with hydraulic and pneumatic units to change spring rate during cornering. For the comparing research between the passive and active system, a two-track vehicle model and a co-simulation model of air spring system are built. For the simulation research on the linear movement of the actuator, a mathematical model is considered as dynamical subsystem in the co-simulation model. To active control the roll angle of vehicle body, a sliding-mode controller with optimized control parameters for the test vehicle is introduced into the model. The characteristics of sliding-mode controller is discussed and the validation of active antiroll control is proved by comparison with other control methods. The results show that the roll angle of air spring vehicle is reduced obviously with the active anti-roll actuator in comparison with that of the passive system. Compared with other control methods, sliding-mode controller has an advantage of shortest switching times, which leads to a longer lifetime of actuator and valves.

Modeling and Simulation of Diaphragm Spring Clutch

A model was developed to simulate a vehicle diaphragm spring clutch with the evaluation indicators of jerk degree and friction work.First,the pressing load characteristic of the driven plate of the diaphragm spring clutch was analyzed.Then,the clutch dynamic characteristic under each state was studied according to the basic principles of tribology.Finally,the mathematical model of the clutch was developed.Based on the model,the performance of a vehicle was simulated.The simulation results show that the model can predict the dynamic characteristic of the clutch correctly and evaluate the performance of the clutch engagement effectively.The model can be used for theoretical research of automatic clutch control and can be easily applied to simulate vehicle longitudinal dynamics.

STEADY STATE RESPONSE ANALYSIS ON HELICAL SPRING IMPACTED BY SHORT WAVE

The wave transmission character of helical spring is applied to establish 2-DOF model of impacted vehicle on the wave impact theory. Considering the concrete structure of helical spring, corresponding responses under different impact frequency of the vehicle are imitated. The reason why the vehicle floor overresponds in some special frequency fields is explored based on analyzing the responses. When the impactions are in low frequency, the change of the spring has not been considered, but this does not affect the results. Because the transmission characters of velocity and acceleration are unanimous in helical spring, the responses characters of velocity and acceleration arc also unanimous, the only difference is the magnitude, which can make use of acceleration responses to analyse velocity responses.

不同类型装配式钢弹簧浮置板减振效果分析

为研究不同钢弹簧数量和钢弹簧刚度参数下装配式钢弹簧浮置板轨道的减振效果,且便于运输吊装,提出了三种类型装配式钢弹簧浮置板轨道。通过建立车辆-轨道-隧道耦合动力学模型对比分析了钢弹簧浮置板轨道的动力性能和减振效果,并在深圳地铁某号线路选取对应类型装配式钢弹簧浮置板结构断面和整体道床断面进行现场测试与仿真结果进行对比验证。研究结果表明:钢弹簧浮置板轨道与整体道床相比,钢轨和浮置板的垂向位移增加了57.23%~95.00%,垂向加速度减小了19.93%~60.13%;钢弹簧浮置板在16~200 Hz内的减振效果明显,最大减振效果可达16.61 dB;钢弹簧浮置板轨道均出现了道床的固有频率向低频偏移和浮置板的隧道壁振动加速度级超过整体道床的现象;三种类型装配式钢弹簧浮置板轨道的减振效果为:类型A>类型B>类型C,其中类型A的减振效果最好;仿真数据与现场实测数据误差率为1.43%~14.25%,减振效果误差在0~1 dB内。

车辆载荷下钢弹簧浮置板轨道振动特性分析

建立车辆-钢弹簧浮置板轨道垂向耦合振动有限元模型,分析车载作用下的浮置板轨道和车辆垂向振动特性。结果表明,钢轨和车体垂向振动在浮置板1阶弯曲频率(10 Hz)、P2共振频率、部分阶次的轮对弯曲频率及车轮辐板模态频率处存在明显峰值,其中车体振动在车体浮沉频率(1 Hz左右)处也存在明显峰值。扣件刚度和阻尼的影响主要在轮对1阶弯曲频率以内的车辆-轨道系统耦合振动行为,扣件阻尼在高频处对轨道垂向振动也有较大影响。钢弹簧刚度和阻尼主要影响浮置板1阶弯曲频率附近的车辆和轨道响应,对车辆运行平稳性影响显著。车辆悬挂参数及车体和构架质量对轨道振动基本无影响,簧下质量通过P2共振以及系统约束下的轮对1阶弯曲和辐板对称伞形模态影响轨道振动。增大一系悬挂刚度和阻尼以及二系悬挂阻尼会增大中高频的车体垂向振动加速度,二系悬挂刚度主要影响车体浮沉频率附近的车体垂向振动。车体、构架和簧下质量对车体浮沉运动、浮置板1阶弯曲和P2共振处的车体振动加速度峰值有影响。

基于灵敏度分析的某商用车悬架系统参数优化

为提高某商用车的行驶平顺性,对某商用车悬架系统参数进行了优化.基于空气弹簧试验数据拟合得到其刚度特性曲线,建立前后悬架及整车多体动力学模型,仿真得出该车随机输入工况和脉冲输入工况平顺性.搭建悬架系统参数化的多平台联合仿真模型,通过全域灵敏度分析得出悬架系统设计参数对平顺性的影响程度.建立整车平顺性多目标响应面近似模型,利用多目标遗传优化算法进行参数可行域内寻优.结果表明:在随机输入工况下,车速为100 km/h时,驾驶员处和乘客处加权加速度均方根值分别减小了12.50%和29.71%;在脉冲输入工况下,车速为30 km/h驾驶员处和车速为20 km/h乘客处的垂向最大加速度分别减小了14.69%和31.28%,优化效果明显.

基于键合图法的履带车油气弹簧阻尼阀特性分析

为优化车辆悬挂的阻尼特性,基于功率键合图法建立油气悬挂阻尼阀阻尼特性的参数化模型。针对阻尼阀压缩行程开阀前、开阀后和复原行程下不同工作模式,分析不同工作状态下阻尼阀的节流形式,结合流体力学知识建立阻尼阀压缩和复原行程的阻尼特性模型。通过模型仿真研究结构参数对阻尼阀特性的影响。设计流量试验台对阻尼阀特性仿真结果进行验证。研究结果表明,基于功率键合图法建立的阻尼阀特性模型可以准确地计算出阻尼阀的特性,减小单向阀芯上通孔2和通孔3的直径可以降低悬挂阻尼阀开阀点速度,调整通孔1和通孔4的直径可以在不影响开阀速度的条件下相应调整阻尼力,通孔6的直径只对复原行程的阻尼力产生影响。

钢弹簧失能下车辆-浮置板轨道耦合系统动力特性研究

在列车荷载作用下浮置板轨道会发生钢弹簧失能,为研究此问题对车辆-浮置板轨道系统动力特性的影响,基于车辆-轨道动力学理论,建立车辆-浮置板轨道耦合动力学模型,研究不同钢弹簧失能数量、位置、组合形式对车辆-浮置板轨道系统动力响应的影响。结果表明:当钢弹簧失能数量相同时,同一块浮置板的振动响应板中位置大于板端位置;钢弹簧失能1个时,板中位置钢轨、浮置板位移最大值分别比板端位置大0.49 mm和0.22 mm,加速度有效值分别比板端位置大13.34%和21.42%;单侧连续失能钢弹簧数量≥2个时,列车荷载作用下钢轨和浮置板垂向位移最大值均分别超出《浮置板轨道技术规范》规定的限值4 mm和3 mm;车体在频域上的振动响应主要集中在10 Hz内,钢弹簧失能会导致车体振动响应在频域上增大;单侧钢弹簧失能2个比双侧失能2个的钢轨位移最大值、加速度有效值分别增大17.75%、2.22%,比正常状态下钢轨位移、加速度分别增大37.08%,10.84%。钢弹簧失能增加了系统的振动响应,影响减振效果,应注意及时检修。

汽车侧门锁弹簧连杆应急快开机构及其性能分析

针对某汽车侧门锁紧急情况下开启需求,提出了弹簧连杆应急快开机构,可实现小开启力和优先级高的开启操作。以奇异位形、棘轮棘爪接触状态和限位接触状态为划分依据,研究了不同工况下应急开启支链在运动过程中的多运动模式和变拓扑结构;经过静力学分析,得到了应急开启的必要条件;通过Adams软件仿真,验证了应急开启支链在车门锁内快速开启的可行性;用控制变量法对应急开启支链的开启时间和开启时间一致性进行研究,主弹簧刚度在5~7 N/mm内,预载荷在75~85 N范围内,主弹簧最大储能位置偏移小,满足开启时间的一致性。提出的弹簧连杆应急快开机构嵌入汽车侧门锁内,满足小开启力、高优先级和开启时间的要求,为应急快开支链设计及性能优化提供了重要理论依据。

面向车门锁电动吸合开启优先功能的凸轮摆杆柔顺连杆组合机构

针对高端汽车门锁电动吸合及开启优先功能需求,提出了凸轮摆杆柔顺连杆组合机构,构造了双凸轮单摆杆和含弹簧构件四杆机构的组合机构,结合限位块、接触状态、凸轮间歇运动、型面突变等构件特征,可实现柔顺自适应滚滑、刚性拨动、避让释放3种运动模式及各模式间切换;嵌入锁内棘轮棘爪锁紧机构,将组合机构转化为电动吸合与开启支链;对应汽车门锁电动吸合、手/电动开启及复位、吸合复位3种工况,以相应驱动方式和运动边界条件,研究分析了吸合运动与锁内现有支链的运动兼容功能、开启优先功能、吸合卡止情况半锁开启功能。将机构及驱动嵌入车门锁进行仿真,研究了全工况开启凸轮与摆杆、摆杆与棘轮、棘轮与棘爪的接触力;机构仿真实现各功能动作的时间与车门锁设计要求匹配,其由半锁到全锁的吸合过程时间为420.97 ms,复位时间为29.03 ms,手动开启时间为622 ms。

特种车辆油气弹簧减振阀可靠性研究

油气弹簧减振阀为特种车辆悬挂装置中的重要部件,针对其应用中受高频载荷易损问题,提出基于Ansys Fluent的油气弹簧减振阀流固耦合可靠性研究方法。基于该方法建立减振阀中阀芯及阀座固体模型与周围油液流体模型,分析0.6、3.96、7.83 Hz激振频率下的减振阀工作状态,研究其安全系数及寿命。结果表明:减振阀阀座在颈部连接处、正对常通孔处易破坏;阀芯易损部位主要集中于阀杆处。研究结果可为减振阀可靠性分析提供参考,亦可服务于后续减振阀薄弱环节优化设计。

基于非线性空气弹簧模型的整车仿真与主客观评价

应用非线性空气弹簧模型,研究了空气悬架整车的动力学仿真和主观评价。结合空气弹簧频率、振幅相关性模型与Simulink仿真,给出了空气悬架整车7自由度模型,对比了不同路面情形下悬架动行程和簧上加速度的均方根值和功率谱密度。从时域和频率2个角度分析了不同速度、路面及减振器阻尼情形下空气悬架整车的动态特性。对装有不同空气弹簧的整车进行主、客观试验测试。结果表明:悬架动行程预测误差小于7%,簧上位置加速度共振峰值预测误差小于6%,共振频率预测误差小于6%;从而验证了所提模型的普适性和精确性;反映了带空气悬架整车的动态特性,解释了平顺性主客观试验的机理。

浅埋爆炸下考虑乘员安全的防雷底板设计理论模型

浅埋爆炸载荷下,为更好地开展装甲车防雷底板设计,建立了考虑附加质量-弹簧-阻尼系统的均质梁动态响应理论模型,并采用有限元仿真分析进行验证,理论与仿真结果吻合良好。基于所建立理论模型,分别讨论了炸药质量、均质梁屈服强度、弹簧刚度、阻尼系数和边界条件对均质梁中点和质量块峰值位移、速度、加速度的影响。结果表明:随着TNT质量增大和均质梁屈服强度减小,均质梁中点峰值位移、质量块峰值位移、速度、加速度都增大;当弹簧刚度相同时,随着阻尼系数的增加,均质梁中点峰值位移减小,质量块峰值加速度增大;当阻尼系数一定时,弹簧刚度对均质梁中点的峰值位移和质量块峰值加速度影响较小;针对不同弹簧刚度,选择适当的阻尼系数可以降低质量块峰值速度。

高超声速飞行器的动态热密封技术研究进展

高马赫数飞行带来的气动热一直是制约飞行器向更大速域和空域发展的最大因素,特别是针对飞行器发动机尾喷管和机体之间、飞行器尾翼控制舵等有较大动态间隙部位,对其进行动态热密封的技术难度也远高于一般的机身表面防热;因此,动态热密封技术成为各国在新型高超声速空天飞行器发展中需要突破的重要瓶颈。本文以X-38等飞行器为例,对国外动态热密封技术进行了简要介绍,并对其主要技术类型和关键性能测试方法进行综述,最后对动态热密封技术的发展进行了总结和展望。

一种公用车审批管理系统

设计了一套公用车审批管理系统,详细介绍了该系统的系统设计、研发管理、应用开挖、接口开发等技术路线和创新点,以及设计方案,旨在通过集成uniapp和SpringBoot技术提高公用车的使用效率和管理规范性,通过自动化和规范化的处理,实现公用车管理的信息化和流程化。

基于COOT算法的城轨车辆车体称重调簧算法优化

现有城轨车辆车体称重调簧模型忽略了车体的非均匀弹性变形、弹簧刚度的非线性等问题。针对该问题,文章首先建立了基于最小二乘法拟合二系支撑位刚度的改进称重调簧模型,该模型相较于传统称重调簧模型更贴合车体的实际负载情况;利用改进白骨顶鸡(COOT)算法对称重调簧算法进行多目标改造和搜索机制优化,相较于模拟退火(SA)算法、粒子群优化(PSO)算法、遗传算法(GA),改进COOT算法使稳定收敛载荷偏差分别降低了3.2 N、2.1 N和7.4 N,收敛速度分别提高了3.5%、6.8%和18.0%,具有更好的精度、效率和鲁棒性;基于C#和MATLAB搭建了整套称重调簧试验系统,并进行模拟试验及实车验证,证明了改进COOT算法及称重调簧系统的准确性和稳定性。