【作者】 王东；

【导师】 张农； 邓谊柏；

【作者基本信息】 湖南大学 ， 车辆工程（专业学位）， 2018， 硕士

【摘要】 空气弹簧因其刚度的非线性、较低的固有振动频率、良好的吸振减振作用,被广泛应用于客车等各类车辆中。由于客车具有载荷大、质心高的特点,空气悬架往往需要匹配尺寸较大的横向稳定杆来保证侧倾稳定性,但是横向稳定杆尺寸过大会对车辆的舒适性产生负面影响。本文提出一种将液压互联悬架(HIS)系统和电子控制空气弹簧(ECAS)系统结合的新型悬架结构,以缓解客车平顺性和操纵稳定性之间的矛盾,能够实现车辆根据行驶条件自适应调节车身高度。首先,本文基于热力学理论建立空气弹簧非线性数学模型,借助Matlab/Simulink平台研究带附加气室空气弹簧的弹性特性。仿真得到不同初始压力下前悬架空气弹簧正弦激励工况下的响应,通过与动弹性特性试验结果比对,验证模型的正确性。再求取空气弹簧的动刚度曲线并讨论关键参数对空气弹簧动刚度的影响。其次,基于质心定理、动量矩定理建立整车九自由度模型动力学方程;建立HIS系统的双作动液压缸、阻尼阀、管路、蓄能器等部件的数学模型,并通过边界条件分别将空气弹簧模型和HIS模型与整车机械系统模型进行耦合;开展安装横向稳定杆车辆和安装HIS系统车辆实车操纵稳定性试验,试验结果验证所搭建的整车九自由度模型的正确性,同时也表明HIS系统能够明显提高车辆的操纵稳定性。最后,基于建立的整车模型,进行高度调节控制策略研究以及主要切换参数的确定,通过利用模糊理论控制气囊充放气过程,实现车辆在行驶工况下车身高度调节。仿真结果表明,该控制策略可以实现静态和动态的车身高度调节,具有一定的抗干扰性,精确度较高。同时,本文进行随机输入行驶试验、脉冲输入行驶试验、鱼钩试验、蛇形试验等试验工况仿真分析,讨论车辆处于不同车身高度模式时,车身高度变化对平顺性和操纵稳定性的影响。综上所述,本文建立包含ECAS系统和HIS系统的整车九自由度模型,并利用模糊控制算法对ECAS系统充放气过程进行控制,从而实现车身高度可调。最后通过不同工况下的仿真分析,研究ECAS系统和HIS系统相互结合的新型悬架系统相比于传统悬架的优势。更多还原

【Abstract】 Due to its superior ride comfort performance,the air suspension and its combination with anti-roll bar have been widely adopted in large-size buses.One of the main drawbacks of this kind of suspension configuration is that the limited improvement of the handling stability while maintaining preferable the ride comfort.It is for the fact that a bus always has the higher center of gravity(C.G.)and vulnerable to rollover accident,causing great threat to people’s life and property.In this paper,a new suspension configuration is proposed to balance the compromise between ride and handling performance for a tour bus,which consisted of Hydraulically Interconnected Suspension(HIS)system and Electronic Controlled Air Spring(ECAS)system.The suspension system could automatically change their mode according to the riding condition,and automatically change the height of the vehicle according to the driving conditions to improve passing ability of vehicle.First of all,based on the thermodynamic theory,the dynamic models of the main gas chamber,additional gas chamber and throttle orifice are constructed,and the vibration response characteristic of the air spring with additional air chamber is studied by numerical integral method in Simulink.The dynamic elastic characteristics of the front air spring under different initial pressure are simulated,the correctness of the model is verified by comparison with the experimental data,and the dynamic stiffness value of the air spring is obtained according to the model,and the influence of the key parameters on the dynamic stiffness of air spring is discussed.Then,based on the centroid theorem and the momentum moment theorem,the dynamic equation of the nine-DOF dynamic model of the vehicle is established.For HIS system,the mathematical models of the two-acting hydraulic cylinder,damper valve,pipeline,accumulator and other components of HIS system are established,and the air spring model and HIS model are coupled with the vehicle model through boundary conditions.The simulation of snake test is carried out between a ECAS vehicle with HIS system and the same vehicle with anti-roll bar,and the experimental data are compared to verify the model.the results show that HIS system can obviously improve vehicle’s handling performance.Finally,the formulation of the height adjustment control strategy of ECAS system and the determination of the main switching parameters are carried out,so that the vehicle can adjust the height of the vehicle body according to the driving condition,and the results show that the vehicle can achieve the static and dynamic height adjustment with road interference.Based on the analysis of random road input,fishhook test,snake test and other test conditions,the influence of vehicle body height variation on vehicle ride comfort,and handling stability is discussed.In summary,this paper establishes nine-DOF dynamic model of the vehicle with HIS system and ECAS system.Using fuzzy control algorithm to control the gas charging and discharging process of ECAS system so as to adjust the height of the vehicle.Through the simulation analysis,the influence of the height change on ride comfort and handling performance are discussed.更多还原