【作者】 袁传义；

【导师】 陈龙；

【作者基本信息】 江苏大学 ， 载运工具运用工程， 2007， 博士

【摘要】 转向系统与悬架系统是汽车底盘系统中影响车身姿态的两大关键系统,是保证车辆行驶平顺性、操纵稳定性和安全性的重要组成部件。有关改进悬架结构及控制以提高悬架动态性能,采用动力转向及控制技术提高转向时操纵轻便性和稳定性的研究是车辆工程技术领域的热点课题之一。直至目前,主动/半主动悬架和电动助力转向(EPS)及其控制系统的研究已分别取得了许多成果,但由于悬架系统与转向系统之间具有一定的耦合作用,简单的叠加控制并不能获得最优的综合性能,要获得更优的整车综合性能必须依赖于两个系统的集成控制。本文对半主动悬架系统的关键部件——减振器、半主动悬架与EPS及其集成控制系统进行了较深入的研究。首先,建立了基于转向状态下的半车模型,并建立了包括EPS模型、半主动悬架模型、轮胎模型和路面模型在内的整车多自由度动力学集成模型,分析了半主动悬架系统和EPS系统对车身姿态的影响。第二,将模糊控制应用于半主动悬架和EPS集成控制系统,针对传统的模糊控制规则不可调的特点,引入了一个可调因子,提出了一种带可调因子的自适应模糊控制方法,为设计出具有较好鲁棒稳定性的半主动悬架与EPS集成控制系统提供了理论基础。第三,采用调节节流口开度来改变减振器阻尼的设计思路,设计半主动悬架系统关键部件——可调阻尼减振器,在微型轿车被动减振器的基础上,研制出一种通过步进电机驱动的可调阻尼减振器,并通过台架试验得到步进电机转角和可调阻尼力之间的关系,为集成控制系统尤其是阻尼控制规律设计提供了依据。第四,提出了半主动悬架与EPS自适应模糊集成控制系统设计的新思路,创新设计了半主动悬架系统和EPS系统白适应模糊集成控制策略,开发了基于LPC2131微控制器的半主动悬架与EPS集成控制器硬件,为半主动悬架与EPS集成控制系统的应用研究奠定了基础。第五,在大量仿真计算的基础上,率先进行了半主动悬架与EPS集成控制系统实车道路试验,包括平顺性随机输入试验、蛇行试验、转向盘转角阶跃输入试验等,并将试验结果与仿真计算结果进行对比。最后,应用改进遗传算法对半主动悬架与EPS整车动力学集成控制系统进行多目标优化,使结构参数和控制参数同时达到更优,为集成控制系统的多目标优化应用提供了依据。研究结果表明,仿真计算和试验基本吻合。经过自适应模糊集成控制后的系统与被动系统相比,质心加速度和横摆角速度等都有较大幅度下降,其中质心加速度的峰值平均下降7.8%～10%,标准差平均下降8.3%～23.4%;横摆角速度的峰值下降14.7%,标准差下降12.7%;操纵转矩的峰值下降55.6%,标准差下降53.8%;在人体敏感的频率区域内,质心加速度功率谱密度也有很明显的降低;而且,集成控制比半主动悬架与EPS独立控制具有更好的整车综合性能。自适应模糊集成控制系统较好地协调了车辆转弯时行驶平顺性和操纵稳定性之间的矛盾,使整车在各种行驶工况下均可保证行驶平顺性和操纵稳定性之间的良好匹配,整车的动力学性能得到了有效地改善。更多还原

【Abstract】 The steering system and the suspension system are two big essential systems of the vehicle chassis system which affect the vehicle body attitude, which is the important composition part to guaranteed the vehicles smooth running, the operation stability and the security. Therefore the research related improvement the structure of suspension to enhances the suspension dynamic performance, as well as uses the power steering technical to enhance the handiness and the stable while steering is one of the vehicle project area of technology hot spot topics. This both all had the relatively mature theory in respective research area, but because the suspension system and the steering system are not the two isolated systems, but has certainly mutually the coupling function,Therefore the simple superimposition control cannot obtain the most superior performance of the two systems, therefore as obtain the more superior entire vehicle overall performance to have to rely on the two system control coordinated, namely integrated control. This article has conducted the thorough research to the semi-active suspension shock absorber development, the semi-active suspension system and the electric power steering system integrated control method, and the road test has carried on.Firstly, the half vehicle suspension model based on steering is established, Also had established the entire vehicle multi-degree of freedom dynamics integration model including the electric power steering model, the semi-active suspension model, the tire model and the road surface model, and the influence of semi-active suspension and the electric power steering system to the vehicle body attitude is analyzed.Secondly, the fuzzy control theory is carried on to the integrated control of the semi-active suspension system and the electric power steering system, an adjustable gene is introduced, a self-adaptive fuzzy method with parameter is put forward, has provided foundation for semi-active suspension and the electric power steering and the control system with good robust.Thirdly, based on a car shock absorber foundation, uses the design mentality of the adjustment orifice opening to change the shock absorber damping, one kind of new adjustable damping shock absorber is designed and developed, and through the bench test to obtained the relations between the corner and the adjustable damping force. Some gist for designing the control system was supplied especially for damping control rule.Fourthly, The self-adaptive fuzzy control method is carried on the integrated control of the semi-active suspension and the electric power steering system,The research has developed based on LPC2131 micro controller semi-active suspension and electric power steering controller hardware, It is sustainment to design the semi-active suspension and electric power steering and its control system.Fifthly, based on the simulation calculate, carried on the road test of the integration control system, including the smooth random input experiment, the serpentuate experiment, the steering wheel corner step more inputs experiment and so on. And the results are analyzed contrast with the simulation.At last,considering traditional design method of vehicle semi-active suspension system and electric power steering always design control parameters following structure parameters and it can not obtain the global optimum performance for the system, the multi-objectives optimization using the ameliorated genetic algorithm to the semi-active suspension and the electric power steering entire vehicle dynamics system integration system is carried on to optimize, caused the design parameter and the controlled variable of the integrative system achieves superiorly simultaneously.It was showed that the simulation results were coped with the experiments. In contrast with the passive system, The center of mass acceleration, the pitch rate, yaw rate and roll rate were all reduced obviously after self-adaptive fuzzy integrated control. The peak decreased in average 7.8%-10% for the center of mass acceleration, 14.7% for roll rate and 55.6% for steering torque. The former standard deviation decreased by 8.3%-23.4%,the latter was decreased 12.7% and 53.8%. In human sensitive frequency range,the power spectrum of the center of mass acceleration was reduced obviously. The entire vehicle dynamic performances of integrated system are more excellent than the semi-active suspension and EPS system controlled unattached. In contrast with the passive system, under the integrated control the entire vehicle dynamic. performances had effective improvement, coordinated the vehicles among the smooth running, secure and the operation handiness while steering, under each kind of driving condition guaranteed the entire vehicle to be possible smoothness, the security and the operation stable are well matched.更多还原