悬架K&C特性参数在车辆开发中的应用研究

经试验台测得车辆在各状态各工况下的悬架KC特性参数,在新车型开发过程中有着重要的参考和指导作用。文章以KC特性参数在整车姿态角的确定及前后悬架偏频的平衡计算为例,通过悬架下行程参数等效到车辆从空载到满载状态悬架压缩量,结合轴距计算车辆从空载到满载时整车姿态角差值,用于指导总布置及造型设计;通过悬架刚度和簧上质量参数计算得到悬架偏频,并结合轴距参数对特定车速下前后悬架的偏频进行平衡匹配,以减小车辆通过突起障碍时的角振动从而改善乘坐舒适性,用于指导悬架设计及动力学性能开发。     

车辆侧倾状态估计的研究

针对复杂行驶工况下车辆侧倾状态无法准确测取,因而对车辆侧倾无法有效控制的问题,本文中利用车辆耦合动力学与模糊T-S理论,设计了基于模型的T-S状态观测器算法,实现了复杂工况下车辆侧倾状态的实时有效观测。首先,构建了不同路面激励与转向盘转角工况下的车辆垂向与横向运动学模型;接着,在考虑轮胎受力具有强非线性特点的基础上,提出了基于T-S理论的轮胎T-S模型,并采用"魔术公式"对其进行了仿真验证;然后,基于轮胎T-S模型与整车动力学模型,利用贝叶斯理论,设计整车T-S观测器算法;最后,利用Car Sim软件对标准A/C级路面激励工况下整车T-S观测器实时估计的车辆侧倾角与侧倾率进行仿真验证。结果表明,所设计T-S观测器可有效估计车辆侧倾状态,最大标准偏差不超过12%。     

车辆系统垂向与横向耦合的侧倾状态估计

为有效解决复杂行驶工况下车辆耦合侧倾运动状态无法精确获取,进而对车辆系统操纵稳定性与乘坐舒适性兼顾优化无法提供准确输入的难题,本文中设计了基于车辆垂向与横向耦合动力学的双非线性状态观测器算法,以实现复杂行驶工况下车辆耦合侧倾运动状态的实时准确估计。首先,建立了路面激励模型与整车系统垂向与横向耦合动力学模型;接着,利用无迹卡尔曼滤波方法(UKF)与非线性模糊观测(T-S)理论,设计了非线性状态观测算法,以在不同路面激励工况下对车辆系统簧载质量与侧倾状态进行联合估计;最后,运用CarSim■动力学软件,对比分析了在标准A级与C级路面上进行J-turn试验工况下,采用联合状态观测器(UKF&T-S)实时估计车辆侧倾角与侧倾率的观测精度。结果表明,本文所设计的UKF&T-S观测器可有效估计车辆侧倾状态,且与CarSim■仿真数据相比识别状态标准偏差不超过10%。     

油气悬架耦连形式对车辆稳定性的影响

为各轮独立、同轴交连和对角交连3种耦连形式的油气悬架推导出其垂向力/刚度、侧倾力矩/刚度、俯仰力矩/刚度和扭转力矩/刚度公式,并据此建立了这3种油气悬架的Matlab/Simulink模型,通过仿真得到了悬架垂向、侧倾、俯仰和扭转的刚度特性曲线。对油气悬架Simulink模型与整车Carsim模型进行联合仿真,分析油气悬架不同耦连形式对车辆稳定性的影响。结果表明:油气悬架耦连形式对车辆垂向振动影响较小;对角交连油气悬架的车身俯仰角最小,其它两种耦连油气悬架的车身俯仰角相同且较大;同轴交连油气悬架的车身侧倾角最小,对角交连油气悬架的车身侧倾角次之,各轮独立油气悬架的车身侧倾角最大。     

基于卡尔曼滤波算法的车辆振动状态估计与最优控制研究

在建立2自由度1/4车辆悬架振动模型基础上,提出了利用卡尔曼滤波算法估计车辆行驶振动状态的方法。通过设计卡尔曼滤波算法,对在不平路面上行驶车辆的车身垂向位移、垂向速度和车轮垂向位移、垂向速度状态进行估计,并通过Matlab/Simulink对估计效果进行验证。验证结果表明,该方法能够在不同路面、不同车速下准确估计车辆的相关参数,为汽车主动悬架的最优控制提供了基础。     

重型牵引车空气悬架系统减振器最佳阻尼特性匹配

车辆悬架系统的阻尼决定车辆悬架的特性,对车辆行驶平顺性和安全性具有重要影响。为了设计车辆的最佳减振器,利用悬架系统的最佳阻尼比,分析前后悬架系统减振器最佳阻尼系数,建立减振器最佳速度特性数学模型。利用多体动力学软件ADAMS/Car模块建立了重型牵引车整车刚柔耦合多体动力学模型,进行整车平顺性仿真分析和悬架系统动力学仿真。匹配结果表明,对该悬架系统,减振器所做的匹配设计是正确有效的,改善了悬架系统的运动特性和整车平顺性。     

半主动悬架车辆的整车模糊控制仿真研究

对半主动悬架整车进行动力学分析，以建立的半主动悬架整车模型为研究对象，将整车划分成8个板块，针对车身的垂直、侧倾、俯仰3种运动设计不同的模糊控制策略，控制磁流变阻尼器的电流输出，达到改善车辆垂直、侧倾和俯仰振动的综合减振目的；以某型车的参数进行仿真分析，仿真结果表明采用文中提出的整车模糊控制策略能很好地改善车辆的舒适性。     

电机-变速器集成驱动系统扭转振动控制的研究

针对电动汽车的电机-变速器集成驱动系统,提出了一种线性二次型调节器结合观测器的电机控制方案,以抑制系统的扭转振动。以电机机械角速度、车轮角速度和扭转角作为系统状态变量建立了状态方程,并分析了系统的振动特性。仿真结果表明,观测器能够有效地估计状态变量,线性二次型调节器的采用使系统的振动得到了更好的抑制,提高了车辆的换挡质量和行驶性能。     

AMESim在减振器最佳阻尼匹配中的应用

为研究油气悬架减振器主要参数对车身垂直位移的影响,调节节流阀直径以获取最佳阻尼比,运用AMESim的液压元件设计库构建四分之一车体的单自由度振动模型,通过对节流直径进行批运算仿真,将车身在路面随机激励下不同参数值所对应的车身位移响应进行比较,从而获取满意的参数取值范围.仿真结果表明,该方法能有效提高悬架的设计效率,并为整车液压悬架的仿真提供参考.     

舒适性钢板弹簧设计与优化分析

通过对某一轻型商用车进行道路振动试验,发现该车辆在空载工况下的后悬架平均隔振率仅为65%,衰减振动能力一般。而且,当车辆过坑、过坎时,后轮存在明显的跳动现象,严重影响了乘坐舒适性。为了解决上述问题,文章综合运用了匹配设计、仿真与试验的方法,对钢板弹簧的结构进行了优化。对比试验结果表明,在不牺牲整车姿态、操稳性能与可靠性能的前提下,板簧结构优化方案明显提升了悬架的隔振性能与整车的平顺性能。     

键合图理论在汽车纵向角振动主动控制中的应用

本文应用键合图理论建立了汽车5自由度振动系统的键图模型并推导出状态方程，以垂直振动、纵向角振动能量最小和控制能量最小为目标函数，利用状态反馈原理代化出前悬架减振器的最佳控制力，对汽车驶过三角形单凸起时的振动响应进行了计算机仿真分析。结果表明，具有主动控制悬架的汽车，其纵向角振动得到明显的衰减。     

Active Roll Control for Passenger Cars

The development of a mathematical model of a limited bandwidth hydro-pneumatic suspension that is incorporated into a vehicle handling model is described. The combined model is used to evaluate a suitable control strategy for eliminating body roll during a cornering manoeuvre. The philosophy behind the roll control strategy has been to use feedback measurements of the body motions which do not compromise the ride control. A study of the influence of the position of the body motion feedback transducer on the effectiveness of the system to reduce the body roll is presented. Non-linear modelling of the suspension components for a 0.8g cornering manoeuvre has revealed performance limitations. Conclusions are drawn as to the effectiveness of the control scheme.     

消除多余约束全局耦合油气悬架系统的研究

提出了悬架多余约束问题,分析了其产生原因,论述了消除多余约束对减小车身扭转载荷、提高汽车越野性能的意义。介绍了消除多余约束全局耦合油气悬架系统的作用原理和消扭作用缸的设计依据。设计了消除多余约束全局耦合油气悬架系统并进行了试验研究。结果表明,所设计的悬架系统在减小车身扭转载荷方面效果明显。     

键合图理论在汽车振动分析中的应用

本文应用键合图理论建立了汽车5自由度振动系统的键图模型并推导出状态方程。编制了动态仿真程序,计算了国产某轻型越野车和某轻型货车驶过三角形单个凸起时的振动响应,分析了悬架参数对振动的影响,指出了提高该车平顺性的途径。进行了轻型货车实车试验并将试验结果与计算结果做了对照,证明所选模型和所编程序是正确的和实用的。     

Active Roll Control for Passenger Cars

SUMMARY

The development of a mathematical model of a limited bandwidth hydro-pneumatic suspension that is incorporated into a vehicle handling model is described. The combined model is used to evaluate a suitable control strategy for eliminating body roll during a cornering manoeuvre. The philosophy behind the roll control strategy has been to use feedback measurements of the body motions which do not compromise the ride control. A study of the influence of the position of the body motion feedback transducer on the effectiveness of the system to reduce the body roll is presented. Non-linear modelling of the suspension components for a 0.8g cornering manoeuvre has revealed performance limitations. Conclusions are drawn as to the effectiveness of the control scheme.     

Roll- and pitch-plane coupled hydro-pneumatic suspension

Passive fluidically coupled suspensions have been considered to offer a promising alternative solution to the challenging design of a vehicle suspension system. A theoretical foundation, however, has not been established for fluidically coupled suspension to facilitate its broad applications to various vehicles. The first part of this study investigates the fundamental issues related to feasibility and properties of the passive, full-vehicle interconnected, hydro-pneumatic suspension configurations using both analytical and simulation techniques. Layouts of various interconnected suspension configurations are illustrated based on two novel hydro-pneumatic suspension strut designs, both of which provide a compact design with a considerably large effective working area. A simplified measure, vehicle property index, is proposed to permit a preliminary evaluation of different interconnected suspension configurations using qualitative scaling of the bounce-, roll-, pitch- and warp-mode stiffness properties. Analytical formulations for the properties of unconnected and three selected X-coupled suspension configurations are derived, and simulation results are obtained to illustrate their relative stiffness and damping properties in the bounce, roll, pitch and warp modes. The superior design flexibility feature of the interconnected hydro-pneumatic suspension is also discussed through sensitivity analysis of a design parameter, namely the annular piston area of the strut. The results demonstrate that a full-vehicle interconnected hydro-pneumatic suspension could provide enhanced roll- and pitch-mode stiffness and damping, while retaining the soft bounce- and warp-mode properties. Such an interconnected suspension thus offers considerable potential in realising enhanced decoupling among the different suspension modes.     

Control Algorithms for Active Cab Suspensions on Agricultural Tractors

This paper describes active agricultural tractor cab suspensions based on optimal control theory. Control algorithms based on time invariant state feedback and on adaptive control are developed and studied. The influence of different observers and measurement noise levels on the vibration damping capacity are studied as well as the power consumption for the suspensions.

The principle for the adaptive algorithm is based on the parameters in the penalty matrices being varied so that the resulting controller always strives to make optimum use of available travel space. The feedback and observer gains are also changed depending on the characteristics of the vehicle's frame movements.

The results show that it is possible to design an effective active suspension, but that the choice of feedback gains must be dependent on the surface characteristics to reach satisfactory vibration damping performance.     

路面连续减速带下汽车悬架的混沌振动分析

针对汽车通过连续减速带时所产生振动,采用二自由度非线性悬架系统为研究对象,分析其混沌动力学行为,从而实现对系统混沌进行抑制.通过分析高速公路上特殊路段连续减速带的参数和设置方式,建立其静态激励模型和得出动态激励相关函数,以数值仿真研究了非线性汽车模型在此激励下的混沌振动,获得导致系统发生混沌振动的频率条件,及车速、减速...     

Multi-performance analyses and design optimisation of hydro-pneumatic suspension system for an articulated frame-steered vehicle

This study investigates the coupled ride and directional performance characteristics of an articulated frame-steered vehicle (AFSV). A three-dimensional multi-body dynamic model of the vehicle is formulated integrating the hydro-mechanical frame steering and hydro-pneumatic suspension (HPS) systems. The model parameters are obtained from field-measured data acquired for an unsuspended AFSV prototype and a validated scaled HPS model. The HPS is implemented only at the front axle, which supports the driver cabin. The main parameters of the HPS, including the piston area, and flow areas of bleed orifices and check valves, are selected through design sensitivity analyses and optimisation, considering ride vibration, and roll- and yaw-plane stability performance measures. These include the frequency-weighted vertical vibration of the front unit, root-mean-square lateral acceleration during the sustained lateral load transfer ratio period prior to absolute rollover of the rear unit, and yaw-mode oscillation frequency following a lateral perturbation of the vehicle. The results suggested that the implementation of the HPS to the front unit alone could help preserve the directional stability limits compared to the unsuspended prototype vehicle and reduce the ride vibration exposure by nearly 30%. The results of sensitivity analyses revealed that the directional stability performance limits are only slightly affected by the HPS parameters. Further reduction in the ride vibration exposure was attained with the optimal design, irrespective of the payload variations. The vehicle operation at relatively higher speeds, however, would yield greater vibration exposure.     

基于微分几何理论的汽车半主动悬架非线性振动控制

针对汽车悬架系统的非线性特性,采用1／4汽车二自由度悬架模型分析半主动悬架控制。应用微分几何理论得到输出-干扰解耦方法,再经适当的坐标变换将该模型由非线性系统简化成一线性系统,并对此系统进行最优控制,然后通过非线性状态反馈实现对原系统的半主动控制。与被动悬架的仿真结果进行了比较,表明这种针对具有非线性特征的半主动悬架的非线性控制方法是可行的。通过功率谱分析,控制后系统的能量比被动悬架更趋于平均,悬架动态性能更稳定。