切换系统不变集的输出反馈镇定

利用一个非负函数V (x), 推广了小时间状态模可观测和大时间状态模可观测的定义, 提出了小时间V (x)可观测和大时间V (x)可观测的概念. 利用V (x)可观测的概念, 讨论了子系统无源的切换系统不变集的有界输出反馈镇定及动态输出反馈镇定. 利用多Lyapunov函数证明了闭环系统渐近稳定. 仿真例子验证了文中结论正确性.     

MIMO不确定仿射非线性系统输出反馈区域镇定

研究不确定仿射非线性系统的输出反馈镇定,在允许系统存在某类非匹配不确定性 的情况下,为系统构造出动态输出反馈鲁棒控制器,使相应闭环系统渐近稳定,并给出吸引域 的估计.     

一类不确定组合大系统的输出反馈鲁棒控制

本语文研究一类不确定组合大系统的静态输出反馈鲁棒镇定问题,对于含有满足匹配条件的不确定性的一类组合大系统设计出了静态输出反馈鲁棒控制器,使闭环系统状态全局指数稳定。最后给出的传真例子验证了所给结果的有效性。     

一类扩展结构大系统的分散有限时间鲁棒关联镇定

研究一类扩展结构大系统分散有限时间鲁棒关联镇定问题. 扩展结构大系统是在原结构系统上增加新子系统而构成的, 在原系统分散控制律确定不变的情况下, 设计新加入子系统的鲁棒分散控制律, 使扩展后的系统仍能保持有限时间关联稳定. 利用LMI 方法推导此类系统基于状态反馈和输出反馈的分散有限时间关联镇定的充分条件, 并给出扩展子系统的相应控制器的设计方法. 最后通过仿真实验表明了所提出方法的可行性和有效性.

     

仿射非线性联级系统的全局光滑镇定

研究一般的仿射非线性联级系统的全局光滑可镇定.在其一子系统为光滑反馈无源的条 件下,运用无源性原理和动力学系统的极限集理论,给出了整个联级系统全局镇定的充分条 件,拓展了现有的全局镇定结果.最后给出两个例子予以说明.     

基于反馈线性化的MIMO非最小相位系统指数镇定

针对仿射多输入多输出非线性非最小相位系统,提出了一种新的镇定方案.用反馈线性化解耦系统输入输出关系,通过高增益状态反馈镇定系统外部动态,用模型预测控制镇定内部动态,所设计控制器能保证闭环系统的指数稳定性.仿真结果表明了所提出方法的有效性和优越性.     

一类开关切换系统的输出反馈镇定

对一类子系统为线性的开关切换系统进行观测器设计，并给出系统动态输出反馈可镇定的充分条件。在所设计的观测器基础上，以系统状态的观测值为依据设计各子控制器和切换方案，使整个闭环系统是指数渐近稳定的。对于切换时间间隔受限制的情况，给出了相应的动态输出反馈可镇定条件和镇定控制方案。实例仿真结果表明，所给出的设计方案是可行的。     

关于一类混合动态系统能控性与镇定的研究:一个例子

线性切换系统是一类重要的混合动态系统模型. 线性切换系统的镇定是一个基本研究问题. 针对一个线性切换系统的具体例子, 分析能控性和可镇定性的关系. 指出能控的线性切换系统是可以通过定常状态反馈镇定的.     

带有非匹配不确定性非线性系统的线性动态输出反馈镇定

研究了带有非匹配不确定性的SISO及MIMO仿射和非仿射非线性系统的动态 输出反馈镇定问题,在仅要求标称系统为双曲极小相位,以及在对系统不确定部分做较弱限 制下,分别为所论系统构造出了输出反馈形式的动态补偿器,它们均使相应的闭环系统为 Lyapunov意义下的渐近稳定.所构造的补偿器为线性的,结构简单,易于实现.     

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.     

A remark on inseparability of min-max systems

Min-max systems, or min-max-plus systems are algebraic models of discrete-event dynamic systems. They are nonlinear extensions of the well known linear max-plus system models. The structural property "inseparability" of min-max systems was proposed by us in a recent paper. It turns out that inseparability is equivalent to the property of "irreducibility" proposed recently by van der Woude and Subiono, although the two properties appear in very different forms. We will prove this fact here.     

Stabilization of max-plus-linear systems using model predictive control: The unconstrained case

Max-plus-linear (MPL) systems are a class of event-driven nonlinear dynamic systems that can be described by models that are “linear” in the max-plus algebra. In this paper we derive a solution to a finite-horizon model predictive control (MPC) problem for MPL systems where the cost is designed to provide a trade-off between minimizing the due date error and a just-in-time production. In general, MPC can deal with complex input and states constraints. However, in this paper we assume that these are not present and it is only required that the input should be a nondecreasing sequence, i.e. we consider the “unconstrained” case. Despite the fact that the controlled system is nonlinear, by employing recent results in max-plus theory we are able to provide sufficient conditions such that the MPC controller is determined analytically and moreover the stability in terms of Lyapunov and in terms of boundedness of the closed-loop system is guaranteed a priori.     

极小-极大-加系统(F,G,H)的能达能观性

在数字电路中,两个时间信号通过逻辑电路的"与"门相当于极大运算,"或"门相当于极小运算.因此,极小-极大-加系统可用于数字电路的时间分析.对于非线性极强的极小-极大-加系统(F,G,H),引入了分别能达和上限能观的概念.利用图论的方法给出了极小-极大-加系统(F,G,H)的状态变量xt为分别能达分量的充要条件,同时,还得到了xt为上限能观分量的充要条件.     

Max-plus eigenvector representations for solution of nonlinear H/sub /spl infin// problems: basic concepts

The H/sub /spl infin// problem for a nonlinear system is considered. The corresponding dynamic programming equation is a fully nonlinear, first-order, steady-state partial differential equation (PDE), possessing a term which is quadratic in the gradient. The solutions are typically nonsmooth, and further, there is nonuniqueness among the class of viscosity solutions. In the case where one tests a feedback control to see if it yields an H/sub /spl infin// controller, the PDE is a Hamilton-Jacobi-Bellman equation. In the case where the "optimal" feedback control is being determined as well, the problem takes the form of a differential game, and the PDE is, in general, an Isaacs equation. The computation of the solution of a nonlinear, steady-state, first-order PDE is typically quite difficult. In this paper, we develop an entirely new class of methods for obtaining the "correct" solution of such PDEs. These methods are based on the linearity of the associated semigroup over the max-plus (or, in some cases, min-plus) algebra. In particular, solution of the PDE is reduced to solution of a max-plus (or min-plus) eigenvector problem for known unique eigenvalue 0 (the max-plus multiplicative identity). It is demonstrated that the eigenvector is unique, and that the power method converges to it. An example is included.     

Adaptive neural control of uncertain MIMO nonlinear systems

In this paper, adaptive neural control schemes are proposed for two classes of uncertain multi-input/multi-output (MIMO) nonlinear systems in block-triangular forms. The MIMO systems consist of interconnected subsystems, with couplings in the forms of unknown nonlinearities and/or parametric uncertainties in the input matrices, as well as in the system interconnections without any bounding restrictions. Using the block-triangular structure properties, the stability analyses of the closed-loop MIMO systems are shown in a nested iterative manner for all the states. By exploiting the special properties of the affine terms of the two classes of MIMO systems, the developed neural control schemes avoid the controller singularity problem completely without using projection algorithms. Semiglobal uniform ultimate boundedness (SGUUB) of all the signals in the closed-loop of MIMO nonlinear systems is achieved. The outputs of the systems are proven to converge to a small neighborhood of the desired trajectories. The control performance of the closed-loop system is guaranteed by suitably choosing the design parameters. The proposed schemes offer systematic design procedures for the control of the two classes of uncertain MIMO nonlinear systems. Simulation results are presented to show the effectiveness of the approach.     

Reconfigurable control of Hammerstein systems after actuator failures: stability,tracking, and performance

A new method for the reconfigurable control of stable Hammerstein systems with sector-bounded static nonlinear input characteristics subject to actuator failures is described. It aims at the recovery of the nominal stability, setpoint tracking, disturbance rejection and performance properties by the reconfigured closed-loop system. This article extends the virtual actuator from linear systems to Hammerstein systems and provides sufficient linear matrix inequality conditions for closed-loop stability, and a corresponding synthesis algorithm. It is shown that the approach is robust against uncertainties of the static input nonlinearity in a small-gain sense, and universal in a certain sense. Feasible setpoints for the reconfigured closed-loop system are characterised, and infeasible setpoints are projected to feasible ones. An extension guarantees minimum performance loss. The method is successfully experimentally evaluated using a system of interconnected tanks.     

A direct parametric approach to spacecraft attitude tracking control

Through the direct parameter approach, a solution for spacecraft attitude tracking is presented. First of all, the spacecraft attitude tracking control model is built up by the error equation of the second-order nonlinear quaternion-based attitude system. Based on the control model, a suitable controller is designed by the direct parameter approach. Compared with other control strategies, the direct parameter approach can offer all degrees of freedom for the controller to satisfy the requirements for system properties and turn the original nonlinear system into closed-loop linear system. Furthermore, this paper optimizes the controller according to the robustness, limitation of controller output and closed-loop eigenvalue sensitivity. Putting the controller into the original system, the state response of the closed-loop system and the output of controller are plotted in Matlab to verify the availability and robustness of the controller. Therefore, the controlled spacecraft can achieve the goal of tracking on the mobile target with the external disturbance torque.     

Stable Model Predictive Control for Constrained Max-Plus-Linear Systems

Discrete-event systems with synchronization but no concurrency can be described by models that are “linear” in the max-plus algebra, and they are called max-plus-linear (MPL) systems. Examples of MPL systems often arise in the context of manufacturing systems, telecommunication networks, railway networks, parallel computing, etc. In this paper we provide a solution to a finite-horizon model predictive control (MPC) problem for MPL systems where it is required that the closed-loop input and state sequence satisfy a given set of linear inequality constraints. Although the controlled system is nonlinear, by employing results from max-plus theory, we give sufficient conditions such that the optimization problem that is performed at each step is a linear program and such that the MPC controller guarantees a priori stability and satisfaction of the constraints. We also show how one can use the results in this paper to compute a time-optimal controller for linearly constrained MPL systems.