【作者】 唐健；

【导师】 薛念文； 江浩斌；

【作者基本信息】 江苏大学 ， 车辆工程， 2010， 硕士

【摘要】 汽车转向系统影响汽车操纵稳定性、主动安全性和乘坐舒适性等性能。电动助力转向作为未来汽车转向的主流技术,将作为标准件装备到汽车上,并将在动力转向领域占据主导地位。这是汽车技术向电子化、智能化发展的必然趋势,是国内外汽车工业界学者研究的焦点。EPS系统是机电耦合的系统,其常规建模推导过程通常较为复杂,容易出错,而键合图理论为能量耦合系统提供了一种直观便捷的建模方法,提高了研究效率。本文以某车型为研究对象,着重研究了电动助力转向系统的结构设计、模型建立、控制方法以及试验评价,主要工作如下：首先,在分析电动助力转向系统设计性能要求的基础上,针对研究车型的特点对EPS系统进行选型,对关键零部件进行设计和校核,并基于CATIA平台对EPS系统进行结构设计和虚拟装配。其次,针对EPS系统机电耦合的特点,为了降低建模难度,提高效率,改变了传统的基于牛顿力学的建模方法,运用键合图理论列画各能域的功率键合图,明确了EPS系统内部的能量传递关系,建立了EPS系统模型,并根据键合图理论的动力学原理在Matlab中进行模拟台架试验的转向操纵性仿真,结果表明所研究的EPS系统建模和仿真方法是有效的。为了研究EPS系统在典型工况下对整车性能的影响,运用ADAMS多体动力学仿真软件建立了整车多体动力学模型,包括前后悬架模型、转向系统模型、轮胎和车身模型、发动机和制动模型。基于Insight平台对模型进行优化,并通过试验验证了模型的准确性。联合采用ADAMS与MATLAB对整车EPS控制性能进行仿真,分别进行了双纽线工况和角阶跃工况的仿真。其中EPS常规助力控制策略中采用基于模糊控制的PD参数自整定控制方法,实现比例和微分控制作用的最佳组合。仿真结果表明EPS系统助力效果明显,整车操纵稳定性得到改善,模糊PD控制比传统PD控制具有更好的稳定性。最后,以国产某轿车为载体,搭载自行设计的控制器,进行实车道路试验,分别进行原地转向试验、双纽线试验、蛇行试验和双移线试验。根据国家标准对试验结果进行分析和评价,结果表明所设计的EPS系统改善了整车的操纵稳定性。更多还原

【Abstract】 The steering system is critical to the handing stability, active security and comfort of the vehicle. Electric Power Steering (EPS) will be the mainstream steering technology in the future and the standard equipment in the vehicle. It will also hold the dominant position in the area of power steering. This technology meets the demand to electronical and intelligent modern vehicles and it has become the focus of researchers in automotive industry from domestic and abroad. The usual modeling and deduction process of electromechanical hybrid EPS system is complex and error-prone. Bond-graph theory provides a visual and convenient modeling method for the multi-energy coupling system, which improves the research efficiency. This article focus on the structure design, model built, control method and test evaluation for EPS system. The major contents are as follows:Firstly, on the basis of analysis performance requirements in design of EPS system, the coloumn assisted EPS system was designed and main parts of the system were checked. The structure of EPS and the virtual assembly were made on the basis of CATIA.Secondly, according to the characteristc of electromechanical hybrid EPS system, based on the Bond-graph theory, the EPS model was built. This decreased the modeling difficulties and improved the efficiency which is different from classical mechanical modeling method. Druing the modeling process, the energy transfer relationship among each energy domain was explicit. The bond graphs of each subsystem were drawn and the simulation model was built with MATLAB accord to the dynamic principle of Bond-graph theory. The steering maneuverability simulation was conducted, which showed a good and speed following assit performance. The result of simulation also showed the modeling and simulation method was effective. Based on these, in order to study the the vehicle performance with EPS under typical work conditions, the mulity body model was built with ADAMS including suspension system, steering system, tire and body, engine and brake system. This model was optimized on the Insight platform and verified accord to the road test result.The next, the vehicle with EPS performance was co-simulated by both ADAMS and MATLAB. Fuzzy PD control method was taken as a general assist control strategy for EPS system, in order to achieve the best combination of the proportion and the differential. The double lane change and step input simulations were made. The result showed the improvement in vehicle stability and fuzzy PD control is more stable than conventional control.Finally, vehicle road tests were carried out with the designed controller. According to the national standard, the pivot steer, Lemniscate test, snake test and double lane change test were carried out and evaluated. The result showed that the designed EPS system improved the vehicle handing stability.更多还原