基于主动悬架系统车辆的道路友好性

为分析悬架系统对车辆道路友好性的影响,设计出可提高道路友好性的主动悬架系统最优控制器,及可分析基于最优控制策略的主动悬架系统,以及被动悬架系统的道路友好性动态仿真模型,仿真分析得出车辆在两种典型的A、B级路面行驶时,基于最优控制策略的主动悬架系统及被动悬架系统车辆对路面造成的动载荷.利用动态载荷系数、动态载荷应力因子及95百分位综合四次幂力三种典型道路友好性评价指标对两种悬架系统的道路友好性进行分析比较.结果表明,采用动态载荷系数、动态载荷应力因子对悬架系统的道路友好性进行评价时,在A级路面上,主动悬架系统的道路友好性分别是被动悬架系统的1.5、1.6倍;在B级路面上主动悬架系统的道路友好性是被动悬架系统的1.5、2.5倍;采用95百分位综合四次幂力指标评价两种悬架系统的道路友好性时,在A级路面上,两种悬架系统的道路友好性相差无几;在B级路面上主动悬架系统的道路友好性比被动悬架系统提高2.5倍.因此,具有合理控制参数的基于最优控制策略的主动悬架系统可提高重型车辆的道路友好性.     

装有液压互联悬架的某型SUV车辆动力学分析及路试验证

提出一种新型油气互联悬架,用于替代传统车辆所使用的稳定杆,在基本不影响车辆其他性能的前提下有助于提高抗侧翻性能。为研究该悬架对某型SUV车辆操纵稳定性的影响,搭建了基于CarSim/Simulink/AMESim的联合仿真平台,建立了液压互联悬架的整车机液耦合的多体动力学模型。仿真结果表明,装有液压互联悬架的整车在操纵稳定性评价中得分较高。为了验证该仿真平台的正确性和进一步研究该油气互联悬架对车辆性能的影响,基于某型SUV车辆开发了整套油气互联悬架样车,并进行了路试。实验结果与仿真结果吻合较好,从而验证了仿真平台的正确性,为后续该类悬架的设计和优化提供一种新的计算机仿真方法。实验和仿真结果表明,在不影响车辆舒适性的前提下,液压互联悬架能提供较大的侧倾刚度,增强高速转弯时车辆的安全性,提高车辆的操纵稳定性。     

小型救助船舶主动式液压互联悬架系统的设计与仿真

传统小型救助船舶悬架系统一般采用被动式弹簧阻尼悬架,船舶的舒适性和操纵稳定性较差,应用范围具有局限性。针对这一问题,提出一种新型主动式液压互联悬架系统。该悬架系统充分利用互联的液压回路,削弱波浪对救助船舶本体造成的冲击和振动,并能主动地调节船体姿态,以提高救助船舶对波浪的适应能力。基于AMESim平台,搭建液压悬架系统的动力学模型,并对模型进行联合仿真,分析不同海况下悬架的动态特性。研究结果表明:与传统被动式弹簧阻尼悬架相比,主动式液压互联悬架系统的波浪自适应能力较好,能提高救助船舶在极端海况下的安全性。     

基于刚柔耦合模型的悬架NVH性能研究

使用有限元软件分析了橡胶衬套对悬架NVH性能的影响。柔化其他悬架部件,建立了多体动力学刚柔耦合模型。通过试验设计(DOE)分析了橡胶衬套刚度对悬架NVH性能的灵敏度并进行了优化。通过对比优化前后仿真结果,可以看出悬架中高频NVH性能得到了改善。将模型仿真与道路模拟机测试结果进行对比,验证了模型的准确性。     

A contemporary adaptive air suspension using LQR control for passenger vehicles

Long rides on irregular roads and infrastructure problems like uncomfortable seating have a very bad impact on human body. The passengers suffer not only physical pain but also stress related problems. Airsprings gain more popularity in passenger vehicles with an increase in demand for ride comfort. Ride comfort and vehicle handling, being the two critical factors of a suspension system often contradict each other. This led to an extensive research on active automobile suspension systems. The authors of this article propose an innovative design of adaptive air suspension system with LQR control strategy. The proposed LQR controller is tuned by Particle Swarm Optimization. A dynamic model of an air suspension system used in passenger vehicles was designed and simulated for both passive and adaptive systems in MATLAB. An experimental evaluation was done to check the performance of the adaptive air suspension system on a vibration shaker table. Air suspension is a non-linear system and thus the authors have derived a stiffness equation for the same with minimal assumptions. A comparative analysis between the most commonly used PID controller and proposed LQR controller was performed over bumps, potholes and ISO standard random roads in MATLAB. Simulation results showed that adaptive air suspension system improves the ride comfort by reducing the maximum displacement amplitude of the vehicle over random roads by 31% while ensuring the stability of the vehicle by reducing the settling time by 85%. The experimental results of an adaptive air suspension system subjected to random vibrations of frequencies between 5 Hz to 20 Hz, exhibited a reduction of sprung mass acceleration by about 30% demonstrating that the proposed controller is effective for random vibration inputs.     

基于变论域模糊控制的车辆半主动悬架控制方法

针对车辆半主动悬架系统,提出了一种基于变论域模糊PID控制方法,目标是提高车辆在随机路面激励作用下的平顺性。通过将变论域方法与模糊PID控制器相结合来解决模糊PID存在的因模糊规则制定盲目性而产生的在线调节时间过长等问题。由仿真和实验研究对比可知,变论域模糊PID控制下的半主动悬架系统中的车身垂直振动速度和加速度比常规PID控制下的车身垂直振动速度和加速度分别减小了46.56%和29.21%,相比被动悬架系统的车身垂直振动速度和加速度分别减小了58.05%和49.74%。使用该车辆半主动悬架模糊控制方法可提高车辆的平顺性。     

三缸机传动系扭振试验研究和仿真分析

动力总成的传动系统扭振问题一直是汽车噪声、振动和声振粗糙度(noise,vibration and harshness,简称NVH)领域研究的热点和难点,针对某型三缸机中型多用途汽车(multi-purpose vehicles,简称MPV)高挡位低转速加速时车内振动和噪声问题,基于半消声室转鼓客观测试试验,运用传递路径分析方法,建立了传动系路径激励的识别方法。针对该三缸机动力总成,建立六自由度三缸机传动系扭振集总参数动力学模型,利用Matlab-Simulink软件进行仿真分析,实现了传动系扭振的准确预测和传动系扭振关键参数的分析。研究发现,传动系扭振受到发动机燃烧扭矩、发动机转速、传动系转动惯量和扭转刚度的影响显著,提出的传动系扭振前期开发策略为整车NVH性能的开发奠定了基础。     

车辆转向系统共振频率的测算方法的研究与应用

目前人们对减少汽车的噪音,振动和声振粗糙度（NVH）的期望比以往任何时候都要近切。车辆转向系统中的NVH表现形式一种是车辆高速行驶或发动机怠速时的转向系统的振动,另一种是电动转向器的助力电机产生的助力振动和液力动力转向器的液压助力振动造成的转向系统的振动。减少转向系统振动的有交方法是减少振动力,尽可能的使转向系统的固有振频率与车体的共振频率以及振动力的频率不一致。因此准确评估转向系统的共振频率是很必要的。本文介绍了在实车上对转向系统进行共振频率的测量和计算的几种方法。     

油气悬架的应用及性能控制研究进展

油气悬架既具有传统的被动悬架性能，又具有慢主动悬架结构特征的综合性能，能够最大限度满足工程车辆平顺性和操纵稳定性方面的要求。根据国内外各类油气悬架系统先进技术及应用，分析了油气悬架系统性能控制的研究进展，并进行相应的评价。     

车辆电液馈能型互联悬架特性分析

为了提高馈能悬架的能量回收效果及动力学性能,提出了一种车辆电液馈能型互联悬架结构。根据流量/压降之间的关系,建立了整车7自由度与电液馈能型互联悬架的耦合数学模型,通过正弦激励对车辆电液馈能型互联悬架进行阻尼特性和馈能特性仿真。以四轮随机路面为输入,分析悬架对车辆的平顺性、行驶稳定性的影响。结果表明：阻尼力、馈能功率与激励频率、幅值成正比,馈能功率波动与之成反比,馈能效率随幅值、频率增大而先增大后减小;随机路面下,与被动悬架相比,电液馈能型互联悬架的俯仰模式、侧倾模式均可以改善动力学性能的同时实现振动能量的回收。     

重型多轴车辆互连油气悬架特性分析

以重型多轴车辆互连悬架系统为研究对象,建立了四轴互连油气悬架液压系统数学模型。模型中考虑了管路沿程压力损失、局部压力损失和油缸活塞杆运动摩擦力的影响,并进行仿真分析,通过台架试验验证了模型的正确性。基于互连油气悬架液压系统数学模型,对比分析了垂向和侧倾工况下互连悬架和独立悬架的刚度和阻尼特性,以及对互连悬架阻尼特性进行参数化分析。结果表明：在垂向工况下,互连悬架蓄能器内气体体积变化量相当于各活塞杆进出油缸的体积,与独立悬架蓄能器内气体体积变化量相等,因此互连悬架与独立悬架刚度特性相同,但其阻尼力大于独立悬架;侧倾工况下,互连悬架在增加侧倾刚度的同时也明显增大了阻尼力。两种工况下,独立悬架阻尼特性不变,互连悬架阻尼力随单向阀直径增大、阻尼阀直径增大、油管直径增大、油缸内径减小和活塞杆直径增大而减小。     

油气悬架自适应半主动控制仿真分析

为了降低工程车辆受到的冲击振动，针对简化的车辆模型，利用自适应滤波算法，设计了半主动油气悬架系统的自适应控制器。在仿真研究过程中以路面随机信号为激励源，以操纵稳定性及行驶平顺性为控制目标，与被动油气悬架系统相比，簧上质量加速度、车轮动载荷、悬架动挠度指标得到明显改善，表明白适应滤波技术在工程车辆油气悬架半主动控制中的应用是可行的。     

汽车振动噪声（NVH）控制——汽车工业面临的新问题

汽车NVH（Noise,Vibration,Harshness）特性是汽车五大重要性能之一,是汽车行业与相关汽车零部件行业关注的综合性问题。本文分析了车内振动、噪声的产生原因及传递路径,并给出了汽车主要的减振、降噪、密封零部件（如动力总成悬置、底盘衬套、悬架系统、筒式减振器等）的结构形式,工作原理、发展趋势等,并展望了汽车NVH控制技术的发展前景。     

汽车变速器降噪分析及控制方法研究

汽车结构振动噪声及舒适性已成为评价动力机械产品的重要指标,变速器是汽车传动系统的主要构成部分,变速器的噪声和振动对性能对提高整车的NVH性能极其重要.对变速器的主被动降噪设计进行分析,为国内汽车工程领域提高变速器的NVH性能提供一定的信息和指导.     

Application of Near-Space Passive Radar for Homeland Security

To protect the homeland from terrorist attacks employing explosive devices, revolutionary advances across a wide range of technologies are required. Inspired by recent advances in near-space (defined as the region between 20 km and 100 km), this paper proposes a new passive radar system using opportunistic transmitter as an illuminator and near-space platform as a receiver. This concept differs substantially from current radars. This system can be operated as a passive bistatic or multistatic radar and hence largely immune to jamming. By placing the receiver in near-space platforms, many functions that are currently performed with satellites or airplanes could be performed much more cheaply and with much greater operational utility. These advantages make near-space passive attractive for a variety of applications, many of which fit well with the needs of homeland security. This paper details the role of near-space passive radar as sensor system that can support homeland security applications. The strengths and weakness of near-space passive radar, compared to current spaceborne and airborne radars, are detailed. The signal models and processing algorithms for near-space passive radar are provided. It is shown that the use of cost effective near-space platforms can provide the solutions that were previously thought to be out of reach to remote sensing and government customers.     

基于Chebyshev区间方法的动力总成悬置系统稳健性优化

汽车动力总成悬置系统是车辆的主要隔振系统之一,其性能对整车NVH体验具有重大影响。考虑到动力总成悬置刚度值存在一定程度的偏差或波动,应用Chebyshev区间方法确定动力总成悬置系统固有频率和解耦率随元件刚度值波动的区间范围,通过实例确定其计算精度。以提高悬置系统频率和解耦率的稳健性为目的,按区间优化模型对某轿车悬置系统的频率和解耦率进行稳健性优化。结果表明,基于该优化方法可获得较好的能量解耦率、较高的稳健性并可减小悬置系统振动传递率。     

汽车悬架同步振动抑制与能量收集综述与展望

悬架是汽车中的核心关键部件，具有承载和减振的双重功能。传统的悬架系统采用黏性液体或干摩擦阻尼器将振动能量转化为热量耗散出去实现减振，造成能量浪费，这尤其对新能源汽车不利。近十年来，既能抑制振动又能收集电能的新型悬架系统受到了高度关注和广泛研究。为了全面掌握汽车悬架同步振动抑制与能量收集技术领域的最新进展，回顾汽车悬架的发展历程，总结汽车悬架从路面激励中可收集的振动能量，重点梳理汽车能量回收悬架技术研究现状，探讨当前面临的技术挑战并对未来发展方向进行了展望。该研究有助于国内同行快速准确地掌握本领域的技术现状，有望为国内新型汽车悬架技术的发展提供重要参考。     

Optimization of secondary suspension of piecewise linear vibration isolation systems

A comprehensive optimal design solution is presented for piecewise-linear vibration isolation systems. First, primary suspension optimum parameters are established, followed by an investigation of jump-avoidance conditions for the secondary suspension. Within the no-jump zones, an optimal design solution is then obtained for the secondary system and overall results are discussed.Averaging method is employed to obtain an implicit function for frequency response of a bilinear system under steady-state conditions. This function is examined for jump-avoidance and a condition is derived which when met ensures that the undesirable phenomenon of ‘jump’ does not occur and the system response is functional and unique. Optimal stiffness and damping parameters for the primary suspension are extracted from a recently established work for passive linear vibration systems. For each point of the primary suspension optimal curve, jump-free zones are identified. Iterating this process, a boundary surface between no-jump (unique response) and jump (multiple-response) areas is established. Keeping optimal parameters for the primary suspension system fixed, the secondary suspension stiffness and damping parameters are varied inside the no-jump zones to explore optimum solutions for the secondary.The root mean square (RMS) of the absolute acceleration is minimized against the RMS of the relative displacement (η). It is observed that there is a certain band of parameters defined by primary damping, within which a valid frequency response can be obtained. An optimum numerical solution is sought within this band of parameters. Optimal solution curves are achieved for the secondary suspension. These can be used in conjunction with the optimal curve for the primary suspension to select design parameter values for the best possible vibration isolation performance in a given application.     

Classification and modeling for in-plant milk-run distribution systems

Material handling is one of the most important issues that should be taken into account for eliminating waste and reducing the cost. It is one of the seven wastes defined in the concept of lean manufacturing. In this study, for a lean material handling system under the lean manufacturing conditions such as pull-based and repetitive manufacturing, a system consisting of periodically moving vehicles in certain routes is taken into consideration. This system is also called milk-run distribution system. Application of milk-run distribution systems in plants standardizes the material handling system and eliminates the waste. Although there are huge numbers of studies related with inbound and outbound logistics, there are few studies especially related with milk-run applications in the manufacturing area. Within this study, based on the observations in real manufacturing environment and limited literature, the milk-run distribution problem in the plants is categorized and explained. For one of the main categories, modeling is performed. The objective of the developed models is to minimize the number of vehicles and the distance traversed. A numerical example inspired by real applications is presented for showing the applicability of the developed models.