磁流变阻尼器模型比较与控制研究

【作者】 王皖君；

【导师】 王恩荣；

【作者基本信息】 南京师范大学 ， 电工理论与新技术， 2008， 硕士

【摘要】 磁流变阻尼器(Magneto-Rheological Fluids Damper,MRD)应用于智能车辆悬架系统设计是一新兴的国际前沿研究课题。由于MRD的阻尼力对外加直流磁场、激励幅度和频率具有很强的依赖特性,且呈强滞环和饱和非线性特性,因此建立准确的MRD特性模型,以及设计能满足智能车辆悬架系统多目标性能、且能补偿MRD滞环非线性特性的混合半主动控制器,是目前急需解决的挑战性任务。论文在综合分析国内外学者提出的MRD各种滞环阻尼力-速度特性模型基础上,提出了MRD的依赖于直流磁场的电流控制特性和依赖于激励性质的滞环算子可分离的半主动控制特性,建立了相应的电流控制与滞环特性相分离的一般化模型,且易于求解其逆模型。应用提出的基于Sigmoid的电流控制函数对典型的非线性滞环双粘滞模型、现象模型、S型滞环模型和通用滞环模型进行了修正,并针对某型号MRD,应用其实验数据对这些修正模型的参数进行了辨识。将这些修正模型分别与四分之一车辆悬架模型相结合,采用经典的“天蓬”半主动控制策略,在谐波、平滑阶跃和随机路面激励作用下,对这些修正模型在不同激励信号作用下的工作特性进行了对比分析研究。结果表明:修正后的模型均具有准确适应控制电流变化的能力,且在不同控制电流和激励作用下,修正模型的计算结果都能较好地拟合试验结果,模型的准确性得到了明显提高。论文进一步应用通用滞环模型和改进的“开-关”阻尼控制律,以及由对称阻尼型MRD产生不对称阻尼特性控制算法,设计了一种基于逆模型的混合半主动控制器。将该控制器与基于通用滞环模型的四分之一车辆悬架模型相结合,在车辆运行速度和负荷,以及路面粗糙程度等条件变化时,对悬架系统的性能和该半主动控制器的鲁棒性进行了系统的分析。结果表明:提出的基于逆模型半主动控制器设计对于车辆运行条件的不确定性具有良好的鲁棒特性,能抑制MRD滞环非线性和“开-关”特性引起的瞬时冲击。该研究成果对实现车辆共振抑制、振动隔离、悬架空间、车轮接地等多目标悬架性能的MRD智能车辆半主动悬架设计具有重要的意义。更多还原

【Abstract】 The intelligent vehicle suspension design applying the magneto-rheological fluids damper (MRD) has become one of international forefront subjects. The damping force of MRD shows heavy hysteresis and saturation nonlinearities and has strong dependences on both applied direct magnetic field and exciting frequency and magnitude, it is thus a challenge task to accurately model characteristics of MRD and synthesis a hybrid semi-active controller to meet the multi-objective performances of vehicle suspension and compensate the hysteresis nonlinearity.The dissertation focuses on reviewing the proposed different hysteretic damping force versus velocity models of the MRD, and further proposes a generalized model which decouples the current control dependence on magnetic field and the hysteron dependence on exciting nature and is easy to derive the inverse model. The proposed current control gain with Sigmoid function is employed to modify the proposed Nonlinear hysteresis bi-viscous model, Phenomenal hysteresis model, S hysteresis model and Generalized hysteresis model, and identify parameters of these models on basis of the measuring data of a candidate MRD. Furthermore, the operation properties of these modified models are systematically compared by combining these models with the quarter-vehicle dynamic model and the classic "Skyhook" control policy, under harmonic, rounded pulse and random road excitations. The results show that these modified models can accurately describe the current control property and better match the measured data, under different drive currents and excitations.A new inverse model based hybrid semi-active controller is further developed, by employing the proposed generalized hysteresis model and the modified "on-off" damping law, as well as the control algorithm for generating asymmetric damping property from the symmetric damping MRD design. The controller is integrated with generalized hysteresis model and the quarter-vehicle dynamic model, so as to systematically evaluate the controller robust and suspension performances under varying vehicle operation speed and load, and varying road surface excitation, the results show that the proposed inverse model based hybrid semi-active controller has enhanced robustness on vehicle operating uncertainties, and can better suppress the hysteresis and switching transient effects of the MRD. The dissertation study plays an important role in improving the MRD intelligent vehicle suspension design to realize the multi-objective suspension performances such as oscillation suppression, vibration isolation, suspension space, road-holding, etc..更多还原