【作者】 陈舒平；

【导师】 管欣；

【作者基本信息】 吉林大学 ， 车辆工程， 2009， 硕士

【摘要】 本文研究的是基于Modelica语言的汽车液压助力转向系统的建模与仿真。在研究过程中建立了面向结构的液压助力转向系的数学模型,并使用Modelica语言建立了转向系的模型库,实现了液压助力转向系统的建模,仿真验证了模型的正确性,分析了模型参数对系统的影响。本文首先分析了目前几种具有代表性的转向系统模型的建模方法和特点,提出了采用统一建模语言Modelica建立液压助力转向系模型的方法。其次,根据实验室已有的模型基础,对汽车液压助力转向系统做了动力学分析,建立了面向结构的转向系机械系统和液压系统的数学模型。最后,以Modelica语言为建模工具,以前面所建的数学模型为基础,在Dymola环境下搭建了转向系的模型库,实现了转向系机械系统和液压系统的统一建模,并对液压助力转向系统进行了仿真验证和分析。更多还原

【Abstract】 The automotive steering system is a specialized mechanism used to maintain or change the driving direction. When driving, it guarantees coordinative steering angle relation for each steering wheel. Moreover, when vehicles are subject to occasional impacts from the road or depart accidently from the original direction, it keeps the vehicles still driving steadily with the cooperation of driving system. As a result, the performance of the steering system directly affects the handling stability, the comfort and the safty of automobiles.It was rare in the past that building structured based models for both the mechanical system and the hydraulic power system in Hydraulic Power Steering system(HPS),which just described the impact from hydraulic system with assist characteristic curves. On the other hand, currently the main method for modeling of HPS or other multi-domain systems is that building models firstly in respective domains using relevant modeling and simulation softwares, then carry out data exchange among models using the linkages of the interfaces in the softwares. However, the application of this kind of modeling method is greatly limited to the interfaces provided by the software companies. As a result, the models have neither openness nor extendsion.Considering the disadvantages of the modeling method stated above, this dissertation adopts a new modeling method, which is modeling and simulation for HPS with Modelica. Based on the consistency of mathematical expressions in physical systems, Modelica supports a model with multi-discipline models by defining the connectors among models. This method achieves the seamless integration and the data communication among models from different disciplines. Therefore, those models have high quality of reusability and extendsion.Based on the current model in our laboratory, State Key Laboratory of Automobile Dynamic Simulation at Jilin University, carry out kinematic and dynamical analysis for components in the steering system. Then build structured-based mathematical models of steering system for both mechanical system and hydraulic system.The main research works carried out in this dissertation are listed as follows: 1、Research on current modeling methods of HPS system.Analyze the modeling methods and the characteristics of representative steering system models, including the SCF steering system model, the NADS steering system model, the steering system model in ADAMS and Carsim, and the steering system model in ASCL2007. Discuss disadvantages of current modeling methods in the steering system, and then propose a new modeling mothed which is modeling and simulation for HPS system with Modelica.2、Study of Modelica modeling language.Study the syntax structure, modeling characteristics and simulation mechanism of Modelica modeling language, understand and master its application of modeling and simulation in multi-domain physical systems.3、Structure based mathematical modeling of Hydraulic Power Steering system.Based on the current ASCL2007 steering system model, abstract the physical model for mechanical system in HPS and build up mathematical models for each component; take dynamic analysis on hydraulic power system in HPS and build structure-based mathematical models for each component.4、Modeling and simulation of Hydraulic Power Steering System with Modelica.Under the modeling environment of Dymola, build up the component models and the connectors in HPS system with Modelica programming. Connect modules with connectors in order to make up a whole model for HPS system and then carry out simulation for model verification and analysis.更多还原