【作者】 吴参；

【导师】 潘双夏； 冯培恩； 王维锐；

【作者基本信息】 浙江大学 ， 机械设计及理论， 2010， 博士

【摘要】 车辆悬架系统是保证车辆行驶平顺性和稳定性的关键部件,半主动悬架形式是悬架发展的一大方向,也是近年来研究的重点热点之一。本文主要就随机路面谱模型、磁流变减振器非线性建模、半主动悬架非线性特性和半主动非线性悬架控制策略这四个半主动悬架研究中的关键问题进行理论与实验研究,取得了如下一些进展：提出一种能同时表征路面不平度和轮迹激励相干性的三维路面谱建模方法。基于二维路面谱模型,深入研究时间域内路面不平度的谐波叠加方法的原理,将其拓展到三维空间内,提出三维路面谱的建模方法,并对其进行数值仿真研究。频谱特性分析表明,该三维路面模型能够很好地模拟实际路面不平度并能有效描述车辆行驶中轮迹激励之间的相干性关系。提出一种新的改进的磁流变减振器Bouc-Wen参数化模型。该模型解决已有的Bouc-Wen模型在低速下滞回环描述不准确,在高速下缺少滞回特性,并无法表述蓄能器造成阻尼力偏置的现象。并将最终的控制变量励磁电流引入了模型,通过实验数据的拟合和验证,表明改进的Bouc-Wen减振器模型能够更准确地磁流变减振器的滞环现象和阻尼外特性。研究使用磁流变减振器的半主动悬架的非线性特性。根据得到的改进Bouc-Wen磁流变减振器模型,建立了四分之一改进Bouc-Wen悬架模型。对比了该非线性悬架与线性悬架的不同点,分析簧载质量、簧下质量、弹簧刚度、悬架阻尼等对非线性悬架整体动力学特性的影响。用混沌理论分析非线性悬架的振动特性,揭示其复杂多变的振动形式。而后通过相空间重构等手段,验证悬架系统在随机路面下存在混沌振动过程,为下一步的半主动悬架控制提供理论依据。提出半主动最优天棚地棚混合控制策略。分析理想天棚阻尼、主动天棚阻尼、主动天棚地棚混合控制、半主动天棚地棚混合控制策略的控制特性,通过反馈线性化的方法,结合混沌VFC控制,设计出半主动悬架控制器,并在自主搭建的四分之一车辆悬架实验台架系统上验证了该控制策略的可实现性和有效性。经过正弦激励扫频试验和随机路面试验,结果表明该控制策略能很好地抑制振动对车身加速度和轮胎动位移的影响。更多还原

【Abstract】 Vehicle suspension system is the key component for riding comfort and stability. Semi-active suspension is the development direction of suspension, but also a key research hotspot in recent years. In this paper, random surface model, damping nonlinear modeling, semi-active suspension nonlinear characteristics of semi-active suspension and nonlinear control strategy are studied in theoretical and experimental research and made some progress as follows:A new approach to simulate three-dimensional road spectrum model, which could represent road surface roughness and coherence of wheelpath excitation, was put forward. The model was obtained by the further study on the sinusoid superposition method, based on two-dimensional road surface spectrum model. It was expanded to three-dimensional space, and was studied by numerical simulation. The spectrum characteristics analysis shows that, the new model reconstructed the time domain model of road surface spectrum and included the coherent relationship between wheelpaths of vehicle driving.A modificatory Bouc-Wen parametric model is proposed, aiming at the nonlinear modeling of MRD. The new model can describe the hysteretic loop in low speed exactly, introduces hysteretic characteristics in high speed and contains the bias of damping force caused by accumulator of single-out-rod damper. The force-velocity and force-displacement curves are obtained by indicator experiment on self-designed large scaled MRD. The modificatory Bouc-Wen model parameters are identified with the test data, and correspond to the practical physical quantities. Then excitation current parameter is introduced to the model. The modificatory Bouc-Wen model is verified by experiment data finally.The nonlinear characteristics of semi-active suspension including modificatory Bouc-Wen model are researched. It analyzed the influence on the varible sprung mass, unsprung mass, spring stiffness and dampering to the nonlinear suspension characteristics. Then it judged the vibration forms of nonlinear suspension on various frequency and amplitude, and studied the path of the suspension vibration to chaos with variety of pavement, by phase portrait, Poincare diagram and bifurcate diagram. Finally, the suspension response under stochastic road irregularities is simulated, and analyzes the time series. It proved that the suspension vibration is chaotic motion. The research ultimately indicates the chaotic behavior under variable situations, and provides the basis for the dynamic design of ground vehicle.The semi-active control strategy of nonlinear suspension is studied based on analyzing the nonlinear force component of MRD. The optimal semi-active sky-ground hook hybrid control method is gain by layer progression from ideal sky-hook control method. The semi-active suspension controller is designed by feedback linearization method. The simulation result shows that the optimal semi-active sky-ground hook hybrid control method can inhibit vehicle body acceleration and dynamic tyre load. Then a quarter suspension vehicle lab system is established. And the effect of optimal semi-active sky-ground hook hybrid control method is verified by experiment.更多还原