【作者】 丁飞；

【导师】 韩旭；

【作者基本信息】 湖南大学 ， 车辆工程， 2013， 博士

【摘要】 液压互联悬架系统作为一种新型悬架系统，具备独立配置悬架系统模式刚度和阻尼的能力。安装液压互联悬架系统的车辆可以获得更好的乘坐舒适性和操纵稳定性，因而有着广泛的应用前景。在液压互联悬架系统为数不多的研究成果中，关于三轴重型商用车液压互联悬架系统的基础理论研究较少。对装有液压互联悬架系统的车辆而言，现今基于非线性微分方程的传统机械液压耦合系统的数值计算方法，只能获得车辆系统评价指标关于液压系统关键性能参数的隐式关系，因而只能对液压系统参数进行定性分析。该方法对研究液压互联悬架系统的附加特性关于液压系统参数的显式定量关系带来困难，同时也影响了对该类悬架系统设计方法研究的开展。本文针对液压互联悬架特性开展系统深入研究，力求在液压互联悬架系统基础理论研究和工程理论计算方面开展一些尝试和探索。本文研究内容主要包括以下几个方面：（1）提出基于阻抗传递矩阵的机械液压耦合系统建模方法。该方法通过将液压系统的液压回路按流体元件进行离散化，离散后回路中各节点之间的状态量通过流体单元的传递矩阵关联，流体单元传递矩阵连乘获得流量呈连续变化油路的通路矩阵。通过在流量跳变处状态量之间的关系，获得液压系统回路在机械液压耦合边界处压力相对于流量的阻抗矩阵。结合机械液压耦合边界处压力和流量与机械运动之间的关系，将由边界处压力所产生的液压力作为外力引入至机械系统动力学方程，最终建立机械液压耦合系统动力学方程。（2）针对三轴重型商用车，提出基于独立悬架运动模式的液压缸互联方式。根据机械系统建模需要，建立并验证具有俯仰运动模式的平衡悬架系统简化模型。通过对双液压缸同向和反向互联方式的研究，获取同向和反向互联对附加刚度和阻尼特性的影响规律。根据该规律，使用阻抗传递矩阵方法，结合液压缸的互联方式，推导独立运动模式下液压系统的阻抗矩阵。（3）开展独立运动模式下液压互联悬架系统特性研究。结合H2评价方法，推导悬架性能响应均值关于液压系统关键参数的显式定量描述。通过引入无量纲算子，获取悬架性能的无量纲表达形式。根据悬架性能关于等效刚度和阻尼的等值关系，获取液压系统关键参数的设计范围。研究抗俯仰液压互联悬架系统的刚度/阻尼矩阵与俯仰平面内传统悬架系统的刚度/阻尼矩阵表达结构的相似性。研究抗侧倾液压互联悬架系统车体和轮组垂向/俯仰、侧倾/翘曲运动模式解耦的必要条件，从理论上验证液压互联悬架具备独立配置刚度/阻尼特性的功能。同时开展液压系统物理参数对上述性能影响的定量分析。（4）基于获得的独立运动模式下装有液压互联悬架系统车辆的动力学方程，研究液压互联悬架系统的稳态振动特性。针对该动力学方程特征矩阵的频域依赖特性，提出用于求解该类矩阵特征值的方法。通过对比求解非频率依赖特征矩阵的特征值问题，验证该方法的正确性。基于辨识获得的特征值和特征向量，结合复模态的“实”运动分析方法，研究抗俯仰液压互联悬架系统和抗侧倾液压互联悬架系统对原车辆系统振动固有频率、模态振型以及车体振荡中心位置的影响，并开展随机路面下的功率谱密度响应分析。（5）对基于显式表达的液压互联悬架系统的参数设计方法进行研究。围绕液压互联悬架性能，开展液压系统关键物理参数的参数化分析。将参数化分析获得的相悖评价指标作为悬架设计的目标函数，采用基于离散变量的悬架设计方法，获得满足性能指标要求的悬架参数组合，并结合无量纲方法和多指标雷达图，对相悖的多个指标性能进行折衷，从而获得最优参数组合。综上所述，本文以液压互联悬架系统为研究对象，研究液压互联悬架系统建模、互联方式和振动特性、参数设计和主观评价方法。本研究为机械液压耦合系统提供新的建模方法，并为液压互联悬架系统的基础理论研究提供新思路，具有较好的学术价值和工程实用价值。更多还原

【Abstract】 The hydraulically interconnected suspension (HIS), as one of the advancedsuspensions, is able to independently adjust the spring/damping rates for eachsuspension mode. The vehicle, equipped with the HIS, has better ride and handlingperformance than that with the conventional suspension. Hence, This suspension hasthe extensively applied foreground. However, few research study has been carried outto explore the theory and mechanism of the HIS system for the tri-axle straight truck.The nonlinear differential equations developed by the conventional method, which isemployed to model the dynamics equations of the mechanical and hydraulic couplingsystem, can only implicitly describe the relationships between the evaluation indicesand the key physical parameters of the hydraulic system, which make it is difficult toinvestigate the explicit quantitative relationships between the additional characteristicsand the key physical parameters, and also affects the development study of the designmethodologies for the HIS system.Therefore, this dissertation systematically investigates the characteristics of theHIS system, and aims at contributing some useful researches and trials on theoreticalanalysis and computation for the HIS system. The main research works of thisdissertation are as follows:(1) A modeling methodology has been proposed based on the impedance transfermatrix method. It discretizes the fluid circuits according to the fluid components, andthe state vector of the adjacent nodes for each fluid component are related to each otherby the transfer matrix of the fluid component. The relationships between the nodes, inwhich the flow changes continuously, are described with the connectivity matrix,which is obtained by production of every individual component transmission matrix.By applying the continuity equation at the nodes, where the flow fluctuates, theimpedance matrix between the flow and pressure at the boundaries can be obtained.The hydraulic strut forces are incorporated into the equations of motion of themechanical system as externally applied forces, which are obtained by therelationships between the boundary flows/pressures and the motions of the mechanicalsystem. Finally, the equations of motion of the mechanical and hydraulic couplingsystem have been derived. (2) The interconnection arrangements have been developed for the tri-axle straighttruck based on the independent mode of the suspension. Based on the requirements forthe modeling of the mechanical system, a simplified model, which is characterized aspitch mode, for the rear tandem axle bogie suspension of the tri-axle straight truck hasbeen developed and evaluated. According to the research of the synchronous andopposite interconnection arrangements between two double-acting cylinders, therelationships between additional characteristics and the interconnection arrangementsare obtained. Based on the obtained results, three new HIS systems have been proposedto implement control for the independent suspension mode. The impedance matrices ofthese hydraulic systems have been derived based on the impedance transfer matrixmethod.(3) The characteristics and mechanism research has been carried out for the HISsystem based on the independent mode of the suspension. The H2performances of theHIS system for the quarter-car have been obtained. The dimensionless expressions forthe H2performances of the HIS system has been derived and explicitly described interms of the dimensionless parameters. Then the feasible design region for the stiffnessand damping parameters is figured out from the contour plot of the suspensionperformances with respect to the stiffness and damping parameters. The analogousexpression for the conventional suspension and pitch resitant HIS systems is alsoinvestigated in the pitch plane. Furthermore, the conditions for the roll resistant HISsystem to decouple the heave and pitch modes, as well as roll and warp modes, for thebody and wheel stations have been studied based on the additional stiffness/dampingmode matrix. It is theoretically proved that the HIS is able to independently adjust thespring/damping rate. Meanwhile, the quantitative analysis of the key physicalparameters on the additional mode stiffness/damping has been made in this thesis.(4) Based on the equations of motion of the mechanical and hydraulic couplingsystem for the independent mode, the steady vibration characteristics have beenstudied. An identification method is proposed to find out the eigenvalues of thefrequency dependent characteristic matrix. This method is evaluated by comparison ofthe eigenvalues of the frequency independent characteristic matrix, which are obtainedwith the conventional method. Based on the identified eigenvalues and eigenvectors,the impacts of the pitch and roll resistant HIS systems on the natural frequencies, modeshapes and the truck body oscillation centers have been studied using the ‘real’ motionanalysis method based on the complex modal theory. The power spectral density responses of the coupling system under stochastic road excitation are also investigated.(5) A parameter design method is presented to optimize the performances of theHIS system. A parametric study has been carried out to analysis the effects of the keyphysical parameters of hydraulic system on the performances. Based on the results ofthe parametric study, the conflict performance indices are assembled as the objectivefunctions. The optimized parameter sets, which satisfy the requirements from theobjective functions, can be found by employing optimum design based on the discretevariables. And the parameter set corresponding to the better compromisingperformances is chosen from the optimized sets in terms of the dimensionless factors,which are displayed by the radar-type chart.In summary, this dissertation, whose research objective is the hydraulicallyinterconnected suspension, has investigated into the dynamics of this proposedsuspension, which involve in modeling, interconnection arrangements and vibrationmechanism, parameter design and subjective evaluation methods. This dissertationpresents a new modeling approach for the mechanical and hydraulic coupling system,and provided a new resolution to the theoretical investigation for the HIS system. As aresult, this dissertation is with rather good academic merits and practical value.更多还原