非线性系统的自适应后推模糊控制设计

发布时间：2018-04-29 14:02

本文选题：非线性系统 + 自适应控制　；参考：《渤海大学》2017年硕士论文

【摘要】：近年来,随着现代科技的快速发展,工业控制系统朝着大规模,复杂的方向发展,这使得控制系统的非线性显著增强。一方面,在诸如机械连接,液压致动器和电伺服电机的致动器和传感器等实际控制工程中经常会出现非光滑非线性函数输入的情况,如死区和饱和等现象。因此,对具有非光滑非线性输入的一类非线性系统的稳定性分析和控制器设计的研究成为了一个热点话题,并且在控制领域已经引起越来越多的关注。另一方面,许多控制系统为了达到一定的性能,对系统的输出或状态具有一定的约束,因此,对于具有约束的非线性系统的控制研究对控制理论本身的发展和实际控制工程系统都具有重要意义。虽然已有许多有关于非线性系统自适应控制问题的研究,但仍存在许多尚未充分考虑的问题。基于此,本论文将基于自适应后推控制方法,对不确定复杂非线性系统进行如下研究:第二章在系统输出受限情形下,研究一类具有输入延迟的严格反馈非线性系统的跟踪控制问题。利用模糊逻辑系统对系统中未知的非线性函数进行逼近,采用Pade近似方法处理系统中存在的输入延迟问题,通过引入barrier Lyapunov函数实现对系统输出的约束。在模糊自适应反推控制框架下,逐步构造出系统控制输入信号,提出保证受控系统稳定性的控制方案。第三章研究一类具有未知死区的Y 时滞纯反馈非线性系统的自适应模糊跟踪控制问题,利用模糊逻辑系统来识别系统中的非线性函数,通过设计适当的李雅普诺夫泛函补偿了时滞问题对系统的影响,借助死区的斜率来解决死区输入问题,进一步,基于自适应后推控制方法,设计了一个新的自适应模糊跟踪控制器,并借助李雅普诺夫稳定性理论证明了系统中的所有变量都是有界的,并保证系统跟踪误差收敛在原点一个小的邻域内。第四章研究一类具有输出受限和输入饱和的非严格反馈非线性系统的自适应模糊跟踪控制问题,利用模糊逻辑系统处理系统中存在的未知非线性函数,通过引入双曲正切函数近似不光滑的饱和输入函数,基于引入的barrier Lyapunov函数,将系统的输出限定在一定范围内。在自适应反推控制框架下,提出保证受控系统性能的自适应模糊控制方案。第五章研究一类具有未建模动态和模糊死区输入的非严格反馈非线性系统的输出反馈控制问题,通过构造一个模糊状态观测器来估计系统中不可测的状态变量,引入去重心法将模糊死区输入进行去模糊化,利用模糊逻辑系统估计系统中未知的非线性函数,结合小增益理论与自适应后推技术,提出能够保证闭环系统中所有变量都是半全局一致有界的自适应模糊输出反馈控制方案。
[Abstract]:In recent years, with the rapid development of modern science and technology, the industrial control system is developing in the direction of large-scale and complex, which makes the nonlinear of the control system significantly enhanced. On the one hand, in practical control projects such as mechanical connections, hydraulic actuators and electric servo motors, such as actuators and sensors, nonsmooth nonlinear function inputs, such as dead-time and saturation, often occur. Therefore, the study of stability analysis and controller design for a class of nonlinear systems with nonsmooth nonlinear input has become a hot topic, and has attracted more and more attention in the field of control. On the other hand, in order to achieve certain performance, many control systems have certain constraints on the output or state of the system. The research on the control of nonlinear systems with constraints is of great significance for the development of control theory itself and for practical control engineering systems. Although there have been many researches on adaptive control of nonlinear systems, there are still many problems which have not been fully considered. Based on this, this paper will do the following research on uncertain complex nonlinear systems based on adaptive backstepping control method: in Chapter 2, the output of the system is limited. The tracking control problem for a class of strictly feedback nonlinear systems with input delay is studied. The unknown nonlinear function in the system is approximated by fuzzy logic system. The input delay problem in the system is solved by using Pade approximation method, and the constraint on the system output is realized by introducing the barrier Lyapunov function. In the framework of fuzzy adaptive backstepping control, the control input signal is constructed step by step, and the control scheme to ensure the stability of the controlled system is proposed. In chapter 3, the adaptive fuzzy tracking control problem for a class of Y delay pure feedback nonlinear systems with unknown dead zone is studied. The fuzzy logic system is used to identify the nonlinear function of the system. By designing appropriate Lyapunov Functionals to compensate the effects of time-delay problems on the system, the dead-zone input problem is solved with the help of the slope of the dead-zone. Furthermore, based on the adaptive backstepping control method, A new adaptive fuzzy tracking controller is designed. By means of Lyapunov stability theory, it is proved that all variables in the system are bounded, and the tracking error of the system is guaranteed to converge in a small neighborhood at the origin. In chapter 4, the adaptive fuzzy tracking control problem for a class of nonstrict feedback nonlinear systems with output constraints and input saturation is studied. The fuzzy logic system is used to deal with the unknown nonlinear functions in the system. By introducing a nonsmooth saturation input function with hyperbolic tangent function, the output of the system is limited to a certain range based on the introduced barrier Lyapunov function. In the framework of adaptive backstepping control, an adaptive fuzzy control scheme is proposed to guarantee the performance of the controlled system. In chapter 5, the output feedback control problem of a class of nonstrict feedback nonlinear systems with unmodeled dynamics and fuzzy dead-time input is studied. A fuzzy state observer is constructed to estimate the unmeasurable state variables in the system. The debarycenter method is introduced to defuzzify the input of the fuzzy dead zone, and the unknown nonlinear function is estimated by the fuzzy logic system, combined with the small gain theory and the adaptive backstepping technique. An adaptive fuzzy output feedback control scheme is proposed to ensure that all variables in the closed-loop system are semi-globally uniformly bounded.
【学位授予单位】：渤海大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP273

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