匹配被动液压互联悬架的某空气悬架客车操纵稳定性研究

发布时间：2019-05-24 10:32

【摘要】：客车由于整体尺寸大、质量重和质心高等特点在高速转弯或避障转向时容易翻车,因此如何提高车辆的动态抗侧倾能力,对客车安全尤为重要;另一方面,具有良好的乘坐舒适性也是驾驶员和乘客对长途客车的基本需求。空气弹簧悬架因其理想的非线性特性而被广泛应用到客车上,空气弹簧可降低悬架系统动挠度、降低车身振动频率、调节车身高度,使客车的乘坐舒适性得到明显的改善。但是对于客车的抗侧倾性能而言,空气弹簧悬架并没有起到明显的提高作用,因此一般需要匹配加粗的横向稳定杆来满足客车的操纵稳定性需求。而横向稳定杆加粗会影响客车的舒适性和轮胎接地性,使得空气弹簧优势降低。针对这一问题,本文设计了一套与空气弹簧匹配使用的液压互联悬架系统。该系统可取代原车的横向稳定杆,在不影响舒适性的前提下,显著提高客车的操纵稳定性,尤其是抗侧倾性能。本文主要围绕液压互联悬架系统对空气悬架客车的操纵稳定性影响展开研究,主要包括以下内容:首先,建立整车动力学模型。通过分析空气弹簧非线性刚度特性,获取空气弹簧在不同预充气体压力状态下的静刚度变化曲线,建立了考虑空气弹簧非线性的机械系统七自由度模型和液压系统模型,并通过耦合边界条件得到了机械-液压耦合的整车动力学模型。其次,进行液压互联悬架系统设计。通过参数识别方法得到了整车模态参数和物理参数,在此基础上进行液压互联悬架系统的设计。以液压系统关键参数组成离散设计变量,在悬架设计目标范围内寻求离散变量集的最佳组合,实现了最佳悬架性能匹配。再次,进行动力学仿真分析。仿真验证了模型和参数的正确性,优化了液压互联悬架系统关键零部件参数,并针对客车操纵稳定性和平顺性进行了基于数学模型的仿真研究,仿真结果显示液压互联悬架系统能够使车身侧倾角刚度增大50%以上,垂向刚度增大5%以内,说明了液压互联悬架系统能够在不影响平顺性的基础上提高操纵稳定性。最后,进行操纵稳定性样车试验。通过蛇形、双移线和稳态回转试验,获取了操纵稳定性客观评价指标,如车身侧倾角、横摆角速度、方向盘转角和不足转向度等,并针对试验结果给出性能评价分值。结果表明,在相同的侧向加速度下,液压互联悬架系统能够使原车的侧倾角减小50%以上,说明整车操纵稳定性显著提高。综上所述,本文研究内容为匹配液压互联悬架系统的空气悬架客车操纵稳定性分析,通过建模、匹配设计及仿真分析进行了客车操纵稳定性的理论研究,并通过样车试验验证了液压互联悬架系统能够显著提高客车操纵稳定性。
[Abstract]:Because of the characteristics of large overall size, heavy mass and high center of mass, it is easy to overturn when turning at high speed or avoiding obstacles, so how to improve the dynamic anti-roll ability of the vehicle is particularly important for the safety of the bus. On the other hand, good ride comfort is also the basic demand of drivers and passengers for long-distance buses. Air spring suspension is widely used in passenger cars because of its ideal nonlinear characteristics. Air spring can reduce the dynamic deflection of suspension system, reduce the vibration frequency of the body, adjust the height of the body, and obviously improve the ride comfort of the bus. However, for the anti-roll performance of passenger cars, the air spring suspension does not play an obvious role in improving the performance, so it is generally necessary to match the thickened transverse stabilizer to meet the handling and stability requirements of passenger cars. However, the thickening of transverse stabilizer will affect the comfort and tire grounding of passenger cars, and reduce the advantage of air spring. In order to solve this problem, a set of hydraulic interconnection suspension system matching with air spring is designed in this paper. The system can replace the transverse stabilizer of the original car and improve the handling stability of the bus, especially the anti-roll performance, without affecting the comfort. This paper mainly focuses on the influence of hydraulic interconnection suspension system on the handling and stability of air suspension passenger cars, including the following contents: firstly, the dynamic model of the whole vehicle is established. By analyzing the nonlinear stiffness characteristics of air spring, the static stiffness curves of air spring under different precharged gas pressures are obtained, and the seven degree of freedom model and hydraulic system model of mechanical system considering the nonlinear of air spring are established. The mechanical-hydraulic coupling dynamic model of the vehicle is obtained by coupling boundary conditions. Secondly, the hydraulic interconnection suspension system is designed. The modal parameters and physical parameters of the whole vehicle are obtained by parameter identification method, on the basis of which the hydraulic interconnection suspension system is designed. The discrete design variables are composed of the key parameters of the hydraulic system, and the optimal combination of discrete variable sets is found in the suspension design target range, and the optimal suspension performance matching is realized. Thirdly, the dynamic simulation analysis is carried out. The correctness of the model and parameters is verified by simulation, the parameters of key parts of hydraulic interconnection suspension system are optimized, and the simulation research based on mathematical model is carried out for the handling, stability and ride comfort of passenger cars. The simulation results show that the hydraulic interconnection suspension system can increase the lateral inclination stiffness by more than 50% and the vertical stiffness by less than 5%. It shows that the hydraulic interconnection suspension system can improve the handling stability without affecting the ride comfort. Finally, the test of handling and stability sample car is carried out. Through serpentine, double moving line and steady state rotation test, the objective evaluation indexes of handling stability, such as body side inclination angle, yaw angular speed, steering wheel angle and insufficient steering degree, are obtained, and the performance evaluation score is given according to the test results. The results show that under the same lateral acceleration, the hydraulic interconnection suspension system can reduce the inclination angle of the original vehicle by more than 50%, which indicates that the handling and stability of the whole vehicle is significantly improved. To sum up, the research content of this paper is the handling stability analysis of air suspension bus matching hydraulic interconnection suspension system, and the theoretical research of bus handling stability is carried out through modeling, matching design and simulation analysis. Through the sample car test, it is verified that the hydraulic interconnection suspension system can significantly improve the handling and stability of the bus.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.33;U461.6

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