一类二阶非线性系统的有限时间状态反馈镇定方法

针对一类二阶非线性系统的有限时间状态反馈镇定问题进行了讨论. 给出了三种基于连续状态反馈的全局有限时间状态反馈镇定方法. 首先,利用非线性齐次系统性质,设计出一种状态反馈控制器,使得闭环系统渐近稳定并且具有负的齐次度;其次,基于有限时间Lyapunov函数的反步构造法,给出了一种有限时间控制器;最后,利用非奇异终端滑模控制技术,得到了一种使闭环系统有限时间收敛到平衡点的反馈镇定控制器. 仿真结果表明了这些方法的有效性.     

基于输出反馈和滑模控制的一类二阶非线性系统有限时间镇定方法

本文研究了一类具有不确定非线性动力学和未知外部扰动的二阶非线性系统的全局有限时间输出镇定问 题. 首先, 提出了一种全局状态反馈有限时间控制器, 实现了二阶非线性系统的有限时间镇定. 为了解决只有系统输 出可用这种更有挑战性的情况, 采用了一种新颖的设计思想, 即非分离原理. 构造了一个有限时间收敛的状态观测 器来估计未知状态. 在此观测器的基础上, 提出了一种基于输出的有限时间复合控制器. 基于李雅普诺夫方法, 证明 了整个闭环系统的全局有限时间稳定性. 仿真结果表明了理论的有效性.     

一类非线性系统的动态反馈有限时间饱和镇定

本文针对一类作线性系统在输入饱和下的有限时间动态反馈镇定问题进行了讨论,提出了一种切换控制策略.通过有限次切换将复杂非线性系统分成不同的简单子系统,使得在每一步切换控制中,状态收敛到所给位置或平衡位置的时间是有限的,且每步的控制器均满足饱和条件.最后给出了一个例子并设计了其有限时间饱和镇定控制器,仿真实验验证了所设计控制器的有效性.     

一类不确定非线性系统的全局鲁棒有限时间镇定

对一类不确定非线性系统提出了一种连续的全局鲁棒有限时间控制律．首先,针对标称系统设计出了一种状态反馈控制律,应用Lyapunov直接稳定性理论和Lasalle不变性原理证明了闭环标称系统的全局渐近稳定性,同时具有负的齐次度;其次,引入辅助变量和采用有限时间收敛的二阶滑模Super—twisting算法,设计出了对不确定性和干扰进行抑制的补偿控制项,并根据有限时间Lyapunov函数给出了补偿控制项参数的取值范围;最后,综合得到一种连续的使实际闭环系统有限时间收敛到平衡点的鲁棒镇定控制律．仿真结果表明了所提控制律的有效性．     

一类受约束非线性系统的有限时间优化镇定

优化控制方法可以考虑系统性能和节省能源,但是不能给出初始稳定区域的描述.本文阐述的优化控制方法可以给出初始稳定区域的描述,使得约束非线性系统有限时间稳定.首先设计有限时间优化控制器使得系统的状态在有限时间内进入初始稳定区域,同时优化目标函数,系统实现性能最优和消耗最小.进而设计有限时间鲁棒镇定控制器使得系统的状态在有限时间内收敛到原点. Lyapunov函数分析方法给出了吸引域的估计,并确保在不同状态下,设计的控制器使得闭环系统有限时间稳定.最后给出了一个仿真实例验证算法的有效性.     

一类非线性系统全局有限时间观测器设计

本文首先讨论了非线性系统的有限时间稳定, 并给出了其全局有限时间稳定的一个充分条件. 然后, 利用几何齐次理论、Lyapunov稳定性理论, 并通过构造一个增益适应律, 对一类具有下三角结构的非线性系统, 讨论其全局有限时间稳定状态观测器的设计问题, 所设计的观测器是连续非光滑的, 能够在有限时间段内实现状态的精确重构.     

一类仿射非线性系统的自适应神经网络输出反馈变结构控制

本文研究了一类仿射非线性系统的输出反馈控制问题. 在介绍文献[4~6]的基础上, 提出一种基于神经网络参数化技术的自适应变结构输出反馈控制方案, 该方案能够避免使用严格正实(SPR)条件, 它不仅能够保证收缩条件的可行性, 而且还可以分析闭环系统的稳态和暂态的一致有界性, 并能够对观测增益和控制参数的选取进行清楚地分析.     

非线性相似组合系统的鲁棒分散输出反馈镇定

首先描述了两具非线性控制系统间输出反馈相似的概念,这种相似性是线性系统理论中输出反馈等价概念的一般化,然后,讨论了由这样的控制系统互联而成的非线性组合系统,这种组合系统仍然具有某种相似结构,充分利用这种相似结构设计出一种鲁棒分散输出反馈控制器,最后的算例说明了所采用方法的有效性。     

离散时间非线性最小相位系统的动态输出反馈镇定

研究了离散时间非线性最小相位系统的动态输出反馈镇定.首先对离散时间非线性系统引入了逼近渐近稳定性的概念.基于此概念,提出了一种动态补偿器设计的新方法.主要结果是,如果一非线性系统的零动态是逼近渐近稳定的,则能用动态输出反馈镇定.动态补偿器的设计是构造性的.     

Finite-time output feedback stabilization of high-order uncertain nonlinear systems

This paper studies the problem of finite-time output feedback stabilization for a class of high-order nonlinear systems with the unknown output function and control coefficients. Under the weaker assumption that output function is only continuous, by using homogeneous domination method together with adding a power integrator method, introducing a new analysis method, the maximal open sector Ω of output function is given. As long as output function belongs to any closed sector included in Ω, an output feedback controller can be developed to guarantee global finite-time stability of the closed-loop system.     

Asymptotic stabilization via output feedback for nonlinear systems with delayed output

We propose a novel and simple design scheme of output feedback controller for a class of nonlinear systems with delayed output. The nonlinear systems considered here are more general than feedforward systems (upper triangular systems). By constructing an appropriate Lyapunov–Krasovskii functional (LKF) and solving linear matrix inequalities (LMIs), the delay-dependent controller making the closed-loop system globally asymptotically stable (GAS) is explicitly constructed. A simulation example is given to demonstrate the effectiveness of the proposed design procedure.     

Finite-time stabilization via dynamic output feedback

In this paper the finite-time stabilization of continuous-time linear systems is considered; this problem has been previously solved in the state feedback case. In this work the assumption that the state is available for feedback is removed and the output feedback problem is investigated. The main result provided is a sufficient condition for the design of a dynamic output feedback controller which makes the closed loop system finite-time stable. Such sufficient condition is given in terms of an LMI optimization problem; this gives the opportunity of fitting the finite-time control problem in the general framework of the LMI approach to the multi-objective synthesis. In this context an example illustrates the design of a controller which guarantees, at the same time, finite-time stability together with some pole placement requirements.     

Finite-time stabilization of output-constrained planar switched systems via output feedback

Finite-time stabilization (FTS) problem of output-constrained planar switched systems via output feedback is investigated in this paper. State feedback control laws are constructed in a systematic way by combining the revamped adding a power integrator technique (APIT) with the elaborately designed logarithm-type barrier Lyapunov function (BLF). By merging the constructed variable-gain switched observers, finite-time output-feedback stabilization, then, is achieved with the output constraint meets too. At the end, simulations are presented to show the effectiveness of the proposed method.     

Bifurcation stabilization of nonlinear systems by dynamic output feedback with application to rotating stall control

The paper deals with the problem of stabilization of stationary bifurcation solutions of nonlinear systems via dynamic output feedback.It is emphasized that the parameter of the system is not directly available.We introduce the concepts of uniform observability of the inverse of a function of state and input and N-order-input-to-state bifurcation stability.Based on the concepts,we propose a new method for designing dynamic compensators that guarantee bifurcation stability for the closed-loop system.As an example,we apply the general theory to active control of rotating stall in axial flow compressors by designing a stabilizing dynamic compensator for the three-state Moore-Greitzer model with a class of cubic compressor characteristics.     

Finite-time output feedback control for a class of stochastic low-order nonlinear systems

This paper discusses the problem of finite-time stabilisation for a class of stochastic low-order nonlinear systems via output feedback. By generalising the adding a power integrator technique, constructing an implementable reduced-order observer and using the stochastic finite-time stability criterion, a finite-time output feedback controller is presented to guarantee that the closed-loop system is finite-time stable in probability. A simulation example is provided to verify the effectiveness of the proposed design method.     

Two results for adaptive output feedback stabilization of nonlinear systems

The problem of (adaptive) stabilization by means of output feedback of a class of nonlinear systems is addressed and solved. The proposed method relies on the asymptotic reconstruction of a stabilizing state feedback control law, does not require stable zero dynamics nor the construction of a Lyapunov function for the closed loop system, and treats in a unified way unknown parameters and unmeasured states. The applicability of the proposed method is discussed via theoretical examples. Finally, it is shown that the proposed method yields a solution to the problem of output feedback regulation for a DC-to-DC power converter and the efficacy of the resulting controller is verified via experiments.