带有未知死区模型的鲁棒自适应模糊控制

针对一类带有死区模型并具有未知函数控制增益的SISO非线性系统，根据滑模控制原理。利用Nussbaum函数的性质，提出一种自适应模糊控制器的设计方案．该方案取消了函数控制增益符号已知和死区模型参数上界、下界已知的条件．通过引入最优逼近误差的自适应补偿项来消除建模误差和参数估计误差的影响．理论分析证明了闭环系统的稳定性和跟踪误差收敛到零．仿真结果表明了该方法的有效性．     

控制增益符号未知的MIMO时滞系统自适应控制

针对一类带有死区模型并具有未知函数控制增益的不确定MIMO非线性时滞系统,基于滑模控制原理和Nussbaum函数的性质,提出了一种稳定的自适应神经网络控制方案.该方案放宽了对函数控制增益上界为未知常数的假设,并通过使用Lyapunov-Krasovskii泛函抵消了因未知时变时滞带来的系统不确定性.理论分析证明,闭环系统是半全局一致终结有界.仿真结果表明了该方法的有效性.     

控制增益符号未知的不确定非线性系统鲁棒自适应控制

针对一类控制增益函数及符号均未知的不确定非线性系统,基于反推滑模设计方法,提出一种鲁棒自适应神经网络控制方案.结合Nussbaum增益设计技术和神经网络逼近能力,取消了控制增益函数及符号已知的条件,应用积分型Lyapunov函数避免了控制器奇异性问题,并通过引入神经网络逼近误差和不确定干扰上界的自适应补偿项消除了建模误差和不确定干扰的影响.理论分析证明了闭环系统所有信号半全局一致终结有界,仿真结果验证了该方法的有效性.     

控制增益符号未知的MIMO 时滞系统自适应控制

针对一类带有死区模型并具有未知函数控制增益的不确定MIMO 非线性时滞系统,基于滑模控制原理和Nussbaum函数的性质,提出了一种稳定的自适应神经网络控制方案 .该方案放宽了对函数控制增益上界为未知常数的假设,并通过使用Lyapunov0Krasovski 泛函抵消了因未知时变时滞带来的系统不确定性. 理论分析证明,闭环系统是半全局一致终结有界.仿真结果表明了该方法的有效性.

     

基本积分型李亚普诺夫函数的直接自适应神经网络控制

针对一类具有下三角形函数控制增益矩阵的非线性系统,基于滑模控制原理,并利用 多层神经网络的逼近能力,提出了一种直接自适应神经网络控制器设计的新方案.通过引入积 分型李亚普诺夫函数及残差与逼近误差和的上界函数的自适应补偿项,证明了闭环系统是全局 稳定的,跟踪误差收敛到零.     

带有摄动死区输入的未知非线性系统自适应模糊控制

用自适应模糊控制来实现对带有摄动死区输入的一类未知非线性系统的控制. 文中给出了一种新的死区执行器模型, 该模型含有时变并且摄动的执行增益. 通过将死区非线性分解为一个线性类似项, 一个非线性项和一个扰动类似项降低了扰动类似项的上界, 从而可以用更小的控制力度来实现系统的鲁棒性. 利用反步后推技术与非线性参数化的模糊逼近器结合导出控制器, 该设计取消了模糊基函数须事先已知的限制. 本文不仅从理论上证明了所给控制器能够保证闭环系统的稳定性和预期的跟踪性能, 还用仿真实验验证了控制器的有效性.     

具有未知非线性死区的自适应模糊控制

基于滑模控制原理，利用模糊系统的逼近能力，提出一种自适应模糊控制方法．该方法提出一种简化非线性死区输入模型，取消了非线性死区输入模型的倾斜度相等以及死区边界对称的条件，还取消了非线性死区输入模型各种参数已知的条件．该方法通过引入逼近误差的自适应补偿项来消除建模误差和参数估计误差的影响．理论分析证明了闭环系统是半全局一致终结有界，跟踪误差收敛到零．仿真结果表明了该方案的有效性．     

一类MIMO非线性系统的直接自适应模糊滑模控制

针对一类具有下三角形函数控制增益矩阵的非线性系统, 基于滑模控制原理, 并利用Ⅱ型模糊系统的逼近能力, 提出了一种直接自适应模糊滑模控制器设计的新方案. 通过引入积分型李雅普诺夫函数及逼近误差自适应补偿项, 证明了闭环系统是全局稳定的, 跟踪误差收敛到零. 仿真结果表明了该方法的有效性.     

一类时滞大系统的分散弹性控制器设计:自适应方法

研究了一类时滞大系统的分散弹性自适应控制器的设计问题.当控制器增益摄动范数 有界但上界未知时,采用自适应方法,给出了系统一致有界稳定的条件和控制器的设计方案,且 该控制器具有在线调整的功能.并给出了特例情况下,即控制器增益摄动范数有界且上界已知 时,闭环系统可镇定的充分条件和相应弹性控制器的设计方案.数值算例说明了设计的可行性 和有效性.     

自适应模糊变结构控制器的一种新设计

针对一类非线性系统,基于一种修改的李亚普诺夫函数并利用Ⅰ型模糊系统的逼近能力,提出一种稳定自适应模糊控制器设计的新方案。该方案能够避免现有的一些自适应模糊／神经网络控制器设计中对控制增益一阶际数上界的要求。理论分析证明了闭环控制系统是全局稳定的,跟踪误差收敛到零。仿真结果表明了该方法的有效性。     

Adaptive output‐feedback tracking for nonlinear systems with rather general control coefficients

This paper studies the problem of global practical tracking by output feedback for a class of uncertain nonlinear systems with unmeasured state‐dependent growth and unknown time‐varying control coefficients. Compared with the closely related works, the remarkableness of this paper is that the upper and lower bounds of unknown control coefficients are not required to be known a priori. Motivated by our recent works, by combining the methods of universal control and deadzone with the backstepping technique and skillfully constructing a novel Lyapunov function, we propose a new adaptive tracking control scheme with appropriate design parameters. The new scheme guarantees that the state of the resulting closed‐loop system is globally bounded while the tracking error converges to a prescribed arbitrarily small neighborhood of the origin after a finite time. Two examples, including a practical example, are given to illustrate the effectiveness of the theoretical results.     

Robust adaptive fault‐tolerant tracking control for uncertain linear systems with time‐varying performance bounds

In this paper, the problem of robust adaptive fault‐tolerant tracking control with time‐varying performance bounds is investigated for a class of linear systems subject to parameter uncertainties, external disturbances and actuator failures. In order to ensure the norm of the tracking error less than the user‐defined time‐varying performance bounds, we propose a new control strategy which is predicated on the generalized restricted potential function. Compared with the existing result, a novel method which provides two design freedoms is developed to reduce the tracking error. According to the online estimation information provided by adaptive mechanism, a fault‐tolerant tracking control method guaranteeing time‐varying performance bounds is developed for robust tracking of reference model. It is shown that the closed‐loop signals are bounded and the tracking error within an a priori given, time‐varying performance bounds. A simulation result is provided to demonstrate the efficacy of the proposed fault‐tolerant tracking control method.     

基于一种修改的李亚普诺夫函数的自适应模糊滑模控制

针对一类不确定非线性系统,基于一种修改的李亚普诺夫函数并利用Ⅱ型模糊系统的 逼近能力,提出了一种稳定自适应模糊控制器设计的新方案.该方案能够避免现有的一些自适 应模糊/神经网络控制器设计中对控制增益一阶导数上界的要求.通过理论分析,证明了闭环模 糊控制系统是全局稳定的,跟踪误差收敛到零.     

Adaptive sliding mode control for plants with mismatched perturbations to achieve asymptotical stability

In this paper an adaptive sliding mode control (ASMC) scheme based on the Lyapunov stability theorem is proposed for a class of multi‐input multi‐output (MIMO) systems with mismatched perturbations to solve robust tracking problems. Adaptive mechanisms are employed in the design of a specific sliding surface function, so that when the dynamics of controlled system enters the sliding surface, the adaptive gains are capable of adapting the upper bounds of mismatched perturbations and the trajectories of tracking errors can achieve the objective of asymptotical stability. Some adaptive mechanisms are also employed in the controller's design, so that the reaching phase can be accomplished in a finite time without the requirement of the information of upper bounds of partial mismatched perturbations. Finally the control scheme is applied to control an AC motor for showing the feasibility of the proposed methodology. Copyright © 2006 John Wiley & Sons, Ltd.     

FUZZY SLIDING MODE CONTROL SYSTEMS WITH ADAPTIVE ESTIMATION

In this paper the design of adaptive sliding mode control for fuzzy systems is discussed. For a complex physical system represented by an amalgamated fuzzy global model that compromises a set of linear models, conditions for the adaptive sliding mode control to stabilize the global fuzzy model are given. The advantage of the control structure is that a priori knowledge of the upper bounds of bounded uncertainties and internal parameters is not required. Numerical simulations are presented to show the effectiveness of the controller.     

Adaptive Output Regulation of a Class of Nonlinear Output Feedback Systems With Unknown High Frequency Gain

This paper presents an output feedback design approach based on the adaptive control scheme developed for nonlinearly parameterized systems, to achieve global output regulation for a class of nonlinear systems in output feedback form. We solve the output regulation problem without the knowledge of the sign and the value of the high frequency gain a priori. It is not necessary to have both the limiting assumptions that the exogenous signal ω and the unknown parameter μ belong to a prior known compact set and the high frequency gain has a determinate lower and upper bounds. The effectiveness of the proposed algorithm is shown with the help of an example.      

控制方向未知的时变非线性系统鲁棒控制

针对一类具有未知时变控制方向、不确定时变参数以及未知时变有界干扰的严反馈非线性系统,给出一种带有死区修正算法的鲁棒控制方法.在控制系数符号未知的情况下,通过在反步法中引入Nussbaum增益和死区修正技术,得到一种修正的鲁棒反步设计方法.该方法不需要未知时变控制系数的上下界先验知识以及不确定参数和外界干扰的上界信息.算法保证了闭环系统所有信号的有界性,同时使得跟踪误差收敛于零的任意小邻域内.     

Robust model reference adaptive control

We propose a new model reference adaptive control algorithm and show that it provides the robust stability of the resulting closed-loop adaptive control system with respect to unmodeled plant uncertainties. The robustness is achieved by using a relative error signal in combination with a dead zone and a projection in the adaptive law. The extra a priori information needed to design the adaptive law, are bounds on the plant parameters and an exponential bound on the impulse response of the inverse plant transfer function.