具有零动态仿射非线性系统控制Lyapunov函数的构造

研究具有零动态仿射非线性系统控制Lyapunov函数的构造问题.提出通过求解一个Lyapunov方程获得可线性化部分的二次型控制Lyapunov函数.由可线性部分的控制Lyapunov函数和零动态部分的Lyapunov函数,通过构造一个正定函数,得到了整个系统的控制Lyapunov函数,且设计了可半全局镇定整个闭环系统的控制律.仿真实例说明了所提出方法的有效性.     

一类非线性系统输出反馈的半全局实用镇定

研究了一类含有未知参数的非线性系统的半全局实用镇定问题,通过系统线性部分和零动态部分的Lyapunov函数构造了整个系统的Lyapunov函数,据此设计了使系统半全局实用稳定的状态反馈和动态输出反馈,且证明了只要未知参数不改变系统的相对阶,那么控制器是鲁棒的.仿真实例说明了所提出方法的有效性.     

基于LMI方法的时滞分布参数控制系统的镇定

针对常时滞、多个常时滞及多个变时滞的分布参数控制系统,提出一种与现有研究分布参数控制系统不同的方法．该方法通过构造平均Lyapunov函数,利用LMI和矩阵不等式知识,在只要求系统本身所固有的系数是负定矩阵的条件下,给出了所研究的分布参数系统镇定的充分条件．当模型中时滞为常时滞时,所得的充分条件与时滞无关;当模型中时滞为变时滞时,所得模型的镇定准则依赖于时滞．此外,该方法一个显著优点是所获得的条件容易检验,因而易于应用．     

一类非线性系统的输出反馈半局鲁棒镇定

从半局镇定角度研究了一类非线性系统的输出反馈镇定问题,这类系统具有较强的非线性增长特征.利用高增益观测器,把非分离设计原则应用于输出反馈半局镇定控制器设计.在不需系统具有一个一致完全可观状态反馈控制器情况下,给出了输出反馈控制器的设计方法.对任意给定紧子集,所设计的反馈控制器使闭环系统是渐近稳定的且吸引域包含指定的紧子集.最后的仿真实例说明了设计方法的有效性.     

一类非线性系统控制Lyapunov函数的构造

The construction of control Lyapunov functions for a class of nonlinear systems is considered. We develop a method by which a control Lyapunov function for the feedback linearizable part can be constructed systematically via Lyapunov equation. Moreover, by a control Lyapunov function of the feedback linearizable part and a Lyapunov function of the zero dynamics, a control Lyapunov function for the overall nonlinear system is established.     

Nonlocal stabilization via delayed relay control rejecting uncertainty in a time delay

Sufficient conditions for a robust relay delayed non‐local stabilization of linear systems are found, which relate the upper bound of an uncertainty in a time delay and the maximum of the real part of system spectrum. Algorithm of delayed relay control gain adaptation for non‐local stabilization is suggested. The proposed algorithm suppresses bounded uncertainties in the time delay: once this relay delayed control law for the upper bound of uncertainty in the time delay for given system is designed, we ensure non‐local stabilization for all values of the time delay less than the upper bound even in the case of a variable delay. Copyright © 2003 John Wiley & Sons, Ltd.     

参数不确定广义大系统的分散鲁棒镇定控制

应用线性矩阵不等式(LMI)方法研究了参数不确定广义大系统的分散鲁棒镇定控制问题，系统中不确定项具有数值界，可不满足匹配条件．基干不确定项的表达形式，给出了存在分散鲁棒控制器的LMI条件．仿真例子表明，LMI方法求解简单、便干应用。     

Non-linear dynamics in adaptive control: Chaotic and periodic stabilization

In this paper the non-linear features of adaptive control algorithms are highlighted. Using a simple “linear” discrete time example, based on classical design, it is demonstrated that in the presence of undermodelling errors, non-linear phenomena in the feedback gain such as limit cycles and even chaos arise. Despite these complicated dynamics, robust stabilization of the plant can still occur. For the class of undermodelling errors considered, the set of plants stabilizable by this adaptive controller is completely characterized.     

Local stabilization of semilinear parabolic system by boundary control

This paper addresses local stabilization of a semilinear parabolic system by boundary control. Under a certain assumption on the nonlinearity of the parabolic equation, a linear boundary feedback control law is applied to control the semilinear system. Based on the operator theories and relations of different norms, locally exponential stabilization of the closed loop system is established. Simulations support the established stability result.     

一类带不确定输入动态非线性系统的输出反馈鲁棒镇定

研究一类带不确定输入动态非线性系统的输出反馈鲁棒镇定问题.通过在高增益观测器引入新的设计参数,改进了通常的高增益反馈控制的设计方法.在输入动态满足零相对阶最小相位的假设下,基于非分离设计原则给出了动态输出反馈控制器的设计方法,所设计的控制器实现了对任意可允许不确定输入动态的全局鲁棒镇定.     

Robust control and tuning problem for distributed parameter systems

In this paper robust multivariable controllers for parabolic distributed parameter systems will be discussed. The purpose of a robust controller is to achieve output regulation, disturbance rejection and insensitivity against some perturbations in the system's and controller's parameters. The robust controller consists of two parts: the unstable servo-compensator and the stabilizing compensator. The servo-compensator will be fixed on the basis of the spectrum of the reference and disturbance signals. The purpose of the stabilizing compensator is to stabilize the extended unstable system that consists of the stable plant and the servo-compensator. In this paper it is proved that the stabilizing compensator can be decomposed into a scalar gain and a matrix gain. A simple sufficient condition for finding stabilizing matrix gains will be given and a straightforward way to compute the gains will be presented. The proposed method is practical in the sense that the dimension of the controller is finite and small, output feedback is used and tuning the controller can be done with the information that can be measured from the stable plant with input-output measurements. To the authors’ knowledge, the main results are new even for finite-dimensional systems.     

Adaptive stabilization for ODE systems via boundary measurement of uncertain diffusion‐dominated actuator dynamics

This paper is concerned with the adaptive stabilization for the ODE systems via boundary measurement of uncertain diffusion‐dominated actuator dynamics. It is worth pointing out that, in the related works, all the states of the diffusion‐dominated actuator are required to be measurable, and this means that an infinite number of sensors are needed to implement the controllers, which is impossible in practice. Quite differently in this paper, only one boundary state of the diffusion‐dominated actuator is measurable and available for feedback design. Moreover, the actuator dynamics contains parameter unknown. Motivated by the existing results, a state observer is first designed to estimate the unmeasurable actuator states, which consists of an input filter and an output filter. Then, by introducing an infinite‐dimensional backstepping transformation, a pivotal target system is obtained from which it is more convenient to design controller and analyze the performance of the original system. Finally, an adaptive controller is constructed by adaptive technique and Lyapunov method, which guarantees that the states of the original system converge to zero, whereas the other states of the closed‐loop system keeping bounded. A simulation example is provided to illustrate the effectiveness of the proposed method. Copyright © 2013 John Wiley & Sons, Ltd.     

基于内流动力学的海洋输油柔性立管鲁棒边界控制

海洋输油柔性立管的振动是引起立管疲劳破坏的主要原因,对其研究边界控制是消除振动疲劳、减少断裂的有效方法.本文引入内流动力学,完善了立管原始无穷维分布参数模型,更好地表达了柔性立管的动力学响应.为抑制柔性立管在内外流激励下的振动奠下基础,本文用Lyapunov直接法对柔性立管系统的稳定性和状态一致有界性进行了证明,设计了边界控制器调节柔性立管的振动,其中控制器使用了符号函数来消除不确定性环境扰动对振动控制效果的影响,提高了系统的鲁棒性.仿真实验表明本文所设计的控制算法有效地减少了柔性立管的振动偏移量.     

Feedback stabilization of a class of distributed parameter systems with control constraints

The feedback stabilization problem for a class of infinite-dimensional linear systems with control constraints is investigated. The approach is developed using a state space system framework which is based on a semigroup formulation. In contrast to the previous works in this direction, it is not assumed that the C₀ semigroup we deal with is a semigroup of contractions. The main result links the problem with the positive invariance of appropriate polyhedral sets. Verifiable necessary and sufficient conditions for this latter property are stated.     

不确定时滞分布参数系统鲁棒控制的LMI方法

对常时滞、变时滞的不确定分布参数控制系统,提出了一种与现有的研究分布参数控制系统不同的鲁棒控制方法.该方法通过构造平均Lyapunov函数,利用线性矩阵不等式知识,在只要求系统本身所固有的系数是负定矩阵的条件下,给出了所给的分布参数系统镇定的充分条件.当模型中的时滞为常时滞时,所得的充分条件与时滞无关.当模型中的时滞为变时滞时,所得模型的镇定准则依赖于时滞.此外,该方法与已有方法比较的一个显著优点就是所获得的条件容易检验,因而易于应用.最后举了一个实例以说明该方法的有效性.     

Global stabilization of the Kuramoto–Sivashinsky equation via distributed output feedback control

This work addresses the problem of global exponential stabilization of the Kuramoto–Sivashinsky equation (KSE) subject to periodic boundary conditions via distributed static output feedback control. Under the assumption that the number of measurements is equal to the total number of unstable and critically stable eigenvalues of the KSE and a necessary and sufficient stability condition is satisfied, linear static output feedback controllers are designed that globally exponentially stabilize the zero solution of the KSE. The controllers are designed on the basis of finite-dimensional approximations of the KSE which are obtained through Galerkin's method. The theoretical results are confirmed by computer simulations of the closed-loop system.     

零点配置与一类非线性广义系统的状态反馈控制

针对状态空间实现为非最小相位的非线性广义系统的控制问题,提出一种非线性广义系统的状态空间实现算法,构建了一个等价于原输出函数的综合输出函数,能任意配置状态空间实现的传输零点,使该状态空间实现为最小相位的.所构建的最小相位输出函数能直接用于构造状态反馈控制器,实现对非线性广义系统状态反馈控制.将所得结论应用于Logistic增长的SIR传染病模型,仿真结果表明了所提方法的有效性和可行性.     

一类不确定热方程自适应边界控制

研究了一类含有不确定控制系数和边界扰动的热方程自适应状态反馈边界控制设计问题. 通过Lyapunov方法, 显式地得到了仅需系统边界状态信息的自适应控制器. 证明了闭环系统状态是L2[0,1]稳定的, 特别是当边界扰动消逝时, 该状态收敛到0. 此外, 通过灵活选取参数调节律的初始条件, 适当放宽了相关文献中相容性条件对系统初始条件的限制. 仿真算例验证了本文方法的有效性.     

A simple robust control for global asymptotic position stabilization of underactuated surface vessels

Global asymptotic stabilization of underactuated surface vessels is generally achieved only by designing complicated controllers. This paper proposes a very simple control law that globally asymptotically stabilizes the position of underactuated surface vessel to a desired constant location and its velocities to zero. The proposed controller is independent of velocity signals and is robust to model parameters. It neither includes an observer nor an adaptive/sliding‐mode law. Controller development and stability analysis rely on a novel Lyapunov function and LaSalle's theorem. Furthermore, by extending the proposed control strategy, a saturated control law is also obtained ensuring the semiglobal asymptotic stability of position error system. Effectiveness of the proposed control schemes is demonstrated by simulation examples. Copyright © 2017 John Wiley & Sons, Ltd.