几类非线性系统基于干扰观测器的干扰抵消研究

发布时间：2018-01-22 17:26

本文关键词： 非线性系统 T-S模糊模型模糊逻辑系统 H_∞控制基于干扰观测器的控制反推控制方法抗干扰控制　出处：《鲁东大学》2017年硕士论文　论文类型：学位论文

【摘要】：众所周知,干扰观测器是通过系统中的已知信息来估计未知干扰的一种有效获得未知干扰的工具,其方法是利用干扰观测器的输出值去估计外源干扰对系统产生的影响,为抑制或补偿干扰提供必备条件.基于干扰观测器的控制(DOBC)是一种非常重要的干扰抵消方法,其基本构造是首先设计干扰观测器或滤波器对干扰进行估计,然后利用干扰的估计值构造前馈补偿器,在前馈补偿中应用干扰的估计值来抵消干扰,并与一般的控制器相复合,最终达到复合闭环系统稳定的目标.DOBC已经应用于许多非线性系统,本文针对不同结构的非线性系统,提出了相应的基于非线性干扰观测器的干扰抵消策略.本文研究的主要内容如下:(1)针对的系统不仅含有未知非线性动态,而且还有未知干扰.先用模糊逻辑系统逼近系统中的未知非线性函数,然后构造以T-S模糊干扰模型为基本的非线性干扰观测器,从而得到干扰的估计值,并利用前馈补偿以抵消干扰,集成自适应控制器可得复合控制器,该方法在抵消干扰的同时,还能够保证复合闭环系统的渐近稳定性.最后,通过仿真检验出此策略的精确性和有效性.(2)考虑一种有不匹配干扰的纯反馈非线性系统,研究其如何抵消外源干扰的问题.系统中的干扰由线性外源系统生成.通过设计非线性干扰观测器得出干扰的估计值用于控制律,提出基于干扰观测器的Backstepping控制方法,可以使得复合闭环系统达到渐近稳定.最后,给出仿真算例验证了该策略是正确的并且也是有效的.(3)研究一类含有未知干扰的一般结构非线性系统,其干扰不在输入通道中且频率未知,将系统及干扰的描述范围相对上一章进行了拓展.本章给出了一种基于两步干扰观测器的抗干扰控制策略,首先设计两步干扰观测器对干扰进行估计,然后设计集成前馈补偿器的复合控制器,抵消未知干扰之后,使得闭环系统为渐近稳定的.并通过数值仿真例子对给出方法的正确性和可行性进行检验.
[Abstract]:As we all know, disturbance observer is an effective tool to estimate unknown disturbance by the known information in the system. The method is to use the output value of the disturbance observer to estimate the influence of the external disturbance on the system. DOBC-based control based on disturbance observer is a very important method of interference cancellation. The basic structure is to design an interference observer or filter to estimate the disturbance, and then to construct a feedforward compensator using the estimated value of the disturbance to counteract the disturbance in the feedforward compensation. And combined with the general controller, finally achieve the goal of stability of the composite closed-loop system .DOBC has been applied to many nonlinear systems, this paper for different structures of nonlinear systems. A corresponding disturbance cancellation strategy based on nonlinear disturbance observer is proposed. The main contents of this paper are as follows: 1) the system not only has unknown nonlinear dynamics. Firstly, the unknown nonlinear function of the system is approximated by the fuzzy logic system, then the nonlinear disturbance observer based on T-S fuzzy disturbance model is constructed, and the disturbance estimate is obtained. Feedforward compensation is used to counteract the interference, and the composite controller can be obtained by the integrated adaptive controller. This method can also guarantee the asymptotic stability of the composite closed-loop system while canceling the interference. Finally. The accuracy and validity of the strategy are verified by simulation. 2) A pure feedback nonlinear system with mismatched disturbances is considered. The problem of how to counteract the external interference is studied. The disturbance in the system is generated by the linear external system. The disturbance estimate is obtained by designing the nonlinear disturbance observer for the control law. A Backstepping control method based on disturbance observer is proposed, which can make the composite closed-loop system asymptotically stable. A simulation example is given to verify that the strategy is correct and effective. (3) A class of general nonlinear systems with unknown disturbances is studied. The disturbance is not in the input channel and the frequency is unknown. The description range of system and disturbance is extended compared with the previous chapter. In this chapter, a disturbance control strategy based on two-step disturbance observer is presented. Firstly, a two-step disturbance observer is designed to estimate the disturbance. Then the composite controller of the integrated feedforward compensator is designed to cancel the unknown disturbance and make the closed-loop system asymptotically stable. The correctness and feasibility of the proposed method are verified by numerical simulation examples.
【学位授予单位】：鲁东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP273

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