基于磁流变阻尼器多项式逆模型的半主动悬架混合H2／H∞鲁棒控制研究

利用多项式模型模拟磁流变阻尼器的环滞特性,根据多项式模型推导了磁流变阻尼器的逆模型。利用混合H2／H∞鲁棒控制算法得到悬架系统所需要的目标阻尼力。将混合H2／H∞鲁棒控制算法和磁流变阻尼器的逆模型接合起来,提出了磁流变阻尼器半主动悬架系统的开环控制策略,并且成功地应用于半主动悬架控制中。     

滞回模型磁流变减振器半主动悬架模糊控制

为了获得磁流变减振器便于控制的精确力学模型,在正弦激励下对磁流变减振器进行了特性试验,利用试验数据拟合了一种滞回模型,以此来表示磁流变减振器的动态响应特性,比较由此模型仿真和实测的阻尼力,表明此模型既能较好地描述其滞回特征,亦能简单明了地表达逆向动态特性,可在开环控制策略下容易地获得理想的阻尼力,利用此模型设计了一个开环控制策略下的模糊控制器,比较所设计的模糊控制器和天棚控制器及被动悬架的性能,采用四分之一悬架模型采进行分析和仿真,随机路面激励下的数值仿真进一步证实了此控制器的有效性,其综合性能比天棚控制和被动悬架均有较大幅度的提高.     

基于磁流变减振器的汽车前悬架半主动控制研究

在磁流变减振器外特性分析基础上，设计了1／4车辆的自适应模糊控制器，提出了把1／4车辆模型的半主动控制算法应用于汽车左右前悬架独立控制的策略，并在Matlab平台上进行了仿真。选用国产某型号微型车作为试验车辆，将其被动的左右前悬架改装成磁流变半主动悬架，在多种条件下进行了实车道路试验。试验结果与仿真吻合，表明对左右前悬架进行独立半主动控制是可行的，明显提高了汽车行驶的平顺性。     

磁流变减振器半主动悬架的系统时滞

时滞导致磁流变减振器可控阻尼力的不同步,降低了车辆半主动悬架的性能及其稳定性,因此时滞问题是近年来半主动悬架的研究热点之一。基于RD-1005-3磁流变减振器的响应特性,在半主动悬架临界时滞理论分析的基础上,建立含有时滞的磁流变半主动悬架的数学模型与传递函数,分析时滞对悬架幅频特性的影响;通过对临界时滞数值解的分析,为磁流变半主动悬架控制系统的时滞研究提供理论依据。在模糊控制策略的基础上,运用Smith预估补偿控制对系统进行时滞补偿,并在Matlab中进行仿真分析。对搭建的单质量磁流变半主动悬架系统进行台架试验,仿真和试验数据均表明进行时滞补偿的系统很好地改善了悬架性能。     

基于磁流变减振器的半主动悬架时滞变结构控制

针对控制输入通道中存在的时滞对磁流变半主动悬架系统控制品质的影响,建立含时滞的1/4汽车磁流变半主动悬架模型。从磁流变半主动悬架系统的时滞微分方程出发,根据滑模变结构控制理论设计出磁流变半主动悬架系统时滞依赖滑模控制器。通过理论推导,利用线性矩阵不等式(Linear matrix inequality,LMI)处理方法把系统时滞稳定的条件转化为LMI可行性分析,保证系统稳定的最大临界时滞求取转化成LMI中的广义特征值最小化问题。Matlab/Simulink仿真及道路模拟振动台上实车试验结果表明,在系统临界时滞范围内,时滞依赖滑模控制器能从根本上保证系统的稳定性,削弱时滞对系统控制效果的影响,有效地改善汽车的乘坐舒适性。     

基于磁流变减振器的汽车半主动悬架非线性控制方法

考虑磁流变减振器阻尼力和悬架弹性元件非线性特性,建立车辆半主动悬架非线性动力学模型。应用微分几何非线性控制,经过适当的非线性状态和反馈变换,实现半主动悬架非线性系统的精确线性化,并对系统实施非线性状态反馈控制;根据预定的控制目标及模糊控制策略调节控制参数,设计模糊控制器,对悬架系统进行了控制仿真研究;利用神经网络模式识别能力对输入数据处理辨别,设计控制网络层,从而达到提高悬架工作性能,改善汽车行驶舒适性的目的。将三种非线性控制方法的仿真结果进行分析比较表明:经模糊控制或神经网络控制后的悬架承受的冲击响应小、振动强度低,比微分几何控制能获得更优异的性能。     

用于汽车悬架的磁流变减振器研究综述

磁流变液在汽车半主动悬架中的应用倍受关注。介绍了磁流变液的特性及磁流变减振器的工作原理,结合国内外最新研究成果,综述了用于汽车悬架的MR减振器的结构形式、仿真模型、控制方法和测试技术,并对今后的研究工作重点进行了探讨。     

车用磁流变减振器的研制

针对车用磁流变减振器现存的阻尼特性不理想、油封易磨损泄漏、磁流变液静置沉降以及磁路结构不尽合理等主要问题,提出了加装单向滑阀、组合密封器、静置稳定装置和多级磁路式电磁活塞等改进措施。以Passat B5轿车前悬架减振器作为设计对象,对磁流变减振器的电磁磁路和液压结构进行了改进设计,最后通过各项性能试验得到了较为满意的结果,表明了双筒滑阀式磁流变减振器的可行性和有效性。     

汽车悬架磁流变减振器的优化设计及仿真

基于磁流变减振器在汽车悬架减振系统半主动控制中的广泛应用,根据磁流变液的特点和磁流变减振器阻尼力与结构参数的关系,设计了新型的磁流变减振器,并对影响磁流变减振器性能的参数进行了优化和仿真.仿真计算表明,该磁流变减振器设计是一种能优化阻尼力的有效算法.     

汽车磁流变半主动悬架控制策略对比研究

在分析磁流变减振器的结构与原理的基础上,建立起较为简化的汽车磁流变减振器数学模型。同时,建立了1/4汽车半主动悬架系统动力学模型及路面谱模型;分别设计了基于磁流变半主动悬架系统的天棚控制器、地棚控制器、PID控制器及模糊控制器,并利用Matlab/Simulink软件进行了仿真试验对比研究。在天棚控制策略下,车身加速度降低16.32%,悬架动挠度降低16.91%;在地棚控制下,车身加速度降低11.29%,悬架动挠度降低2.94%;在PID控制下,车身加速度降低79%,悬架动挠度反而上升73%;在模糊控制下,车身加速度降低21%,悬架动挠度降低12%,轮胎动载荷降低5%。结果表明,模糊控制磁流变半主动悬架有效减小了车身加速度、悬架动挠度、轮胎动载荷,明显地提高了汽车乘坐舒适性和操纵稳定性。     

磁流变减振器原理

这里分析了一种磁流变减振器的原理,用粘度模型描述了磁流变液随外加磁场变化的流变特性,得到的阻尼力方程为这种减振器的设计提供了理论基础。研究结果表明:随着外加磁场的增加,磁流变液的表观粘度增加,减振器产生的阻尼力增大。     

Semiactive nonlinear control of a building with a magnetorheological damper system

This paper proposes a linear matrix inequality (LMI)-based systematic design methodology for nonlinear control of building structures equipped with a magnetorheological (MR) damper. This approach considers stability performance as well as transient characteristics in a unified framework. First, multiple Lyapunov-based controllers are designed via LMIs such that global asymptotical stability of the building structure is guaranteed and the performance on transient responses is also satisfied. Such Lyapunov-based state feedback controllers are converted into output feedback regulators using a set of Kalman estimators. Then, these Lyapunov-based controllers and Kalman observers are integrated into a global nonlinear control system via fuzzy logic. To demonstrate the effectiveness of the proposed approach, a three-story building structure employing an MR damper is studied. The performance of the nonlinear control system is compared with that of a traditional linear optimal controller, i.e., H₂/linear quadratic Gaussian (LQG), while the uncontrolled system response is used as the baseline. It is demonstrated from comparison of the uncontrolled and semiactive controlled responses that the proposed nonlinear control system design framework is effective in reducing the vibration of a seismically excited building structure equipped with an MR damper. Furthermore, the newly developed controller is more effective in mitigating responses of the structure than the H₂/LQG controller.     

Lyapunov theory based robust control of complicated nonlinear mechanical systems with uncertainty

This paper presents a robust control approach for nonlinear uncertain crane systems with a three DOF framework. We deal with an overhead crane in which a trolley located on the top is moved to x- and y-axes independently. We first approximate the nonlinear system model through feedback linearization transformation to simply construct a PD control and then design a robust control system for compensating control deviation feasibly occurring due to modeling error or system perturbation in practice. An adaptive control rule is analytically derived by using Lyapunov stability theory given bounds of system perturbation. We accomplish numerical simulation for evaluating the proposed methodology and demonstrate its superiority by comparing with the traditional control strategy. This paper was recommended for publication in revised form by Associate Editor Dong Hwan Kim Hyun Cheol Cho received a B.S. from the Pukyong National University in 1997, a M.S. from the Dong-A University, Korea in 1999, and a Ph.D. from University of Nevada-Reno, USA in 2006. He is currently a post-doc researcher in the Dept. of Electrical Engineering, Dong-A University. His research interests are in the areas of control systems, neural networks, stochastic process, and signal processing.     

一种磁流变阻尼器的分数阶微分模型

对磁流变阻尼器系统建立分数阶微分方程表征其非线性特征,将系统输出位移信号拟合磁流变阻尼器系统分数阶微分方程,以4个参数拟合这一黏弹性系统,其拟合精度明显高于整数阶微分方程.实验和分析表明,微分方程的阶数与磁流变阻尼器加载的电流有关,加电流时分数阶项阶数较不加电流时明显升高;加电流后分数阶项的阶数随电流强度的增加而增大;同时电流强度越大,系统惯性力的影响越小,黏、弹性力的影响程度也发生变化,控制电流强度越大,黏性力的影响越占优势;当磁流变液达到磁饱和时,模型不再随电流强度的变化发生改变.系统的黏弹特性和系统模型参数也受磁流变液性能和工作条件的影响.     

采用磁流变阻尼器的人体座椅悬架系统模糊ANFIS-PID复合控制技术研究

对座椅悬架用单出杆式磁流变阻尼器进行阻尼特性试验,并借助MATLAB多项式拟合工具箱对改进多项式模型中未知参数进行辨识。分析人体振动特性,建立五自由度人体座椅悬架模型。综合模糊控制器与自适应模糊神经推理系统(Adaptive Neuro-Fuzzy Inference System,ANFIS)整定PID控制器的优点,提出一种模糊ANFIS-PID复合控制策略。采用正弦信号作为外界激励,分别对被动悬架、传统模糊控制、ANFIS-PID控制及模糊ANFIS-PID复合控制人体座椅悬架系统进行仿真分析。结果表明,辨识得出的参数和建立的改进多项式模型均可满足后续仿真要求;采用模糊ANFIS-PID复合控制策略的隔振效果明显优于传统模糊控制及ANFIS-PID控制,能有效改善人体座椅悬架系统的行驶平顺性及驾乘人员乘坐舒适性。     

Modeling and testing of a field-controllable magnetorheological fluid damper

In this study, an experimental and a theoretical study were carried out to predict the dynamic performance of a linear magnetorheological (MR) fluid damper. After having designed and fabricated the MR damper, its dynamic testing was performed on a mechanical type shock machine under sinusoidal excitation. A theoretical flow analysis was done based on the Bingham plastic constitutive model to predict the behavior of the prototyped MR damper. The theoretical results were then validated by comparing them against experimental data, and it was shown that the flow model can accurately capture the dynamic force range of the MR damper. In addition to the flow model, a modified parametric algebraic model was proposed to capture the hysteretic behavior of the MR damper. The superiority of the proposed modified model was shown by comparing it with the Alg model as well as with a widely adopted modified Bouc-Wen model through an error analysis. It is observed that although all the three models are comparable at the excitation velocities of 0.05, 0.10, and 0.15 m/s, the mAlg model is remarkably successful at the highest excitation velocity of 0.2 m/s over the other two. The improvements in the predictions were found to be over 50%, relative to unmodified model especially at lower current inputs. Therefore, it was concluded that the present flow model can be successfully adopted to design and predict the dynamic behavior of MR dampers, while the mAlg model can be used to develop more effective control algorithms for such devices.     

Study on damping properties of magnetorheological damper

To research the properties of a new kind of smart controllable MR (magnetorheological) fluid, in this paper, the rheological models are discussed. On the basis of analyzing the structural forms of MR dampers, an improved structure of the MR damper is introduced; the properties of the novel MR damper are then tested. The experimental results reveal that the Herschel-Bulkley model predicts the force-velocity well; the damping properties of the ameliorated structure of the MR damper have improved; when the excitation is a trigonal signal, the MR damper reveals a thinning effect at high velocity; and when the excitation is a sinusoidal signal, the MR damper reveals a nonlinear hysteretic property between the damping force and relative velocity. Finally, the main unsolved problems have been put forward. __________ Translated from Ningxia Engineering Technology, 2005, 24 (4) (in Chinese)     

基于磁流变阻尼器的受电弓主动控制分析与验证

作动器是受电弓主动控制系统应用的瓶颈,磁流变阻尼器作为新型材料磁流变液发展而来的智能化元器件具有很多优良特性,将其用于弓网接触力的主动调节。首先建立了精确的磁流变阻尼器正向扩展双曲正切模型和逆向简化双曲正切模型,同时建立了和磁流变阻尼器结合的弓网耦合系统模型;为分析其在不同出力时程下的特性,设计了最优控制器、变结构控制器和模糊控制器对受电弓进行控制,并以SSS400+型受电弓为对象进行验证;最后以实际所需的主动控制力为标准,分析了作动器对理论控制力的跟踪能力。研究结果表明:磁流变阻尼器在不同控制策略的出力时程中均有较好表现,由于其较快的反应时间、较好的跟踪精度和较小的能量消耗,将其作为受电弓主动控制系统中的作动器具有很大的应用价值和发展潜力。     

变阻尼半主动振动控制研究现状

半主动控制系统在国内外得到很多关注,已取得了很大的研究进展。通过对结构振动控制的概述,介绍了变阻尼半主动控制的控制装置和控制算法的研究现状,并指出结构振动半主动控制工程应用所面临的几个主要问题。