具有有界时变不确定性的离散时间系统的H∞状态反馈控制

本文对具有有界时变不确定性的离散时间系统的Ｈ∞状态反馈控制问题进行研究。导出了Ｈ∞干扰衰减约束下系统二次稳定的充分条件，给出了一种基于离散代数Ｒｉｃｃａｔｉ方程的带观测器的鲁棒Ｈ∞状态下反馈综合方法。     

具有结构不确定性系统的鲁棒H∞控制*

本文研究具有结构不确定系统的鲁棒Ｈ∞状态反馈控制问题，这个问题的解涉及到一个代数Ｒｉｃｃａｔｉ方程，通过分析，这个问题的解与一个辅助的线性时不变系统的Ｈ∞状态反馈控制问题的解是等价的，把这一结果求解具有结构不确定性系统的鲁棒Ｈ∞动态输出反馈控制问题，很方便地给出只需求解两个代数Ｒｉｃｃａｔｉ方程的鲁棒Ｈ∞动态输出反馈控制问题的解。     

状态时滞时变不确定系统的鲁棒H∞ 输出反馈控制器设计

主要研究了存在状态滞后的线性时变不确定时滞系统的鲁棒∞控制分析和综合问题,给出了对所有容许不确定性,被控对象可二次镇定和满足从干扰输入到控制输出的Ｈ∞范数界约束的动态输入出反馈鲁棒Ｈ∞控制分析结果,将不确定时滞系统的鲁棒Ｈ∞输出反馈控制器设问题等价对两个线性时不变系统的状态反馈标准Ｈ∞控制问题,并由此得到反馈阵和观测阵,了终得到鲁棒Ｈ∞控制器综合设计方法。     

状态和控制输入不确定时滞系统基于观测器的鲁棒H_∞控制

研究一类同时存在状态和控制输入不确定性的时滞系统基于观测器的鲁棒Ｈ∞控制问题。系统的不确定性参数是时变的,但其结构已知。通过构造观测器并利用观测器状态进行反馈控制,使系统不仅鲁棒镇定,而且具有一定的Ｈ∞性能。鲁棒Ｈ∞控制器的设计可通过求解两个代数Ｒｉｃｃａｔｉ方程得到     

状态和控制输入不确定时滞系统基于观测器的鲁棒H∞控制

研究一类同时存在状态和控制输入不确定性的时滞系统基于观测器的鲁棒Ｈ∞控制问题。系统的不确定性参数是时变的,但其结构已知。通过构造观测器并利用观测器状态进行反馈控制,使系统不仅鲁棒镇定,而且具有一定的Ｈ∞性能,鲁棒Ｈ∞控制器的设计可通过求解两个代数Ｒｉｃｃａｔｉ方程得到。     

关于组合系统的分散Ｈ∞控制

本文考虑线性组合系统的分散状态反馈Ｈ∞控制问题。以Ｒｉｃｃａｔｉ－ｌｉｋｅ方程半正定解的术语给出了一个使得给定的组合系统稳定并且对干扰抑制保证一个Ｈ∞界限制的分散状态反馈控制设计。对具有对称循环结构的组合系统，得到一个简单的分散控制设计程序。作为一个应用，对一族线性系统的同时Ｈ∞控制问题的可解性导出了一个充分条件。     

非线性时滞摄动系统的H∞鲁棒控制

研究具有时滞的非线性不确定性系统的Ｈ∞鲁棒控制问题。基于代数Ｒｉｃｃａｔｉ方程的正定解设计出状态反馈控制器使得闭环系统满足相应的Ｈ∞鲁棒性能准则。     

混合灵敏度问题的鲁棒H-/LTR设计方法

本文对具有输出乘型不确定性的Ｈ∞混合灵敏度问题进行了研究，提出了一种新的鲁棒Ｈ∞／ＬＴＲ设计方法。这种设计方法由三部分组成：首先针对偶系统设计一个Ｈ∞全状态反馈控制，使得系统满足性能和鲁棒性要求。其次设计一个全状态观测器，使得上述状态反馈的特性得以恢复，最后综合出满足原系统性能和鲁棒性要求的输出反馈动态控制律。     

不确定广义模糊系统的鲁棒模糊H∞控制器设计

研究了不确定广义模糊系统鲁棒H∞状态反馈控制器和动态输出反馈控制器设计问题。在E确定其它系数矩阵均存在不确定性情况下，给出鲁棒模糊H∞状态反馈控制器和动态输出反馈控制器存在的充分条件。鲁棒H∞状态反馈控制律的设计可能通过求解线性矩阵不等式得到，而动态输出反馈鲁棒H∞控制器可通过定义新变量得到，所求控制器使闭环系统对所有的不确定性稳定且满足H∞性能指标γ。     

不确定线性系统混合H2/H∞鲁棒输出反馈控制

解决了在系统状态空间模型的状态与输出矩阵中含有范数有界 参数不确定线性系统的混合Ｈ２／Ｈ∞鲁棒输出反馈控制问题,所推导的满阶控制器对于所有呆容许的参数不确定都能满足给定的Ｈ∞干扰衰减水平,且为最坏情形Ｈ２代价函数提供了一个最优的上界,所得的结果需要求解一个含有尺度参数的修正代数Ｒｉｃｃａｔｉ方程以及三个含有尺度参数的交叉耦合非线性方程,而且也给出了一个求解这些含有尺度参数非线性方程的数值算法。     

线性参数不确定系统的H-鲁棒控制器设计

本文主要讨论了带有未知不确定参数的线性系统的H_∞鲁棒控制问题,这里假定其中的不确定性是时变有界的,并同时存在于系统的状态矩阵和输入矩阵中,文中提出了一种同时使受控对象保持二次稳定并满足干扰约束的状态反馈设计方法。结果表明,该类反馈控制律可以通过求解一个含有参数的代数Riccati方程得到。     

An optimal control approach to robust tracking of linear systems

In our early work, we show that one way to solve a robust control problem of an uncertain system is to translate the robust control problem into an optimal control problem. If the system is linear, then the optimal control problem becomes a linear quadratic regulator (LQR) problem, which can be solved by solving an algebraic Riccati equation. In this article, we extend the optimal control approach to robust tracking of linear systems. We assume that the control objective is not simply to drive the state to zero but rather to track a non-zero reference signal. We assume that the reference signal to be tracked is a polynomial function of time. We first investigated the tracking problem under the conditions that all state variables are available for feedback and show that the robust tracking problem can be solved by solving an algebraic Riccati equation. Because the state feedback is not always available in practice, we also investigated the output feedback. We show that if we place the poles of the observer sufficiently left of the imaginary axis, the robust tracking problem can be solved. As in the case of the state feedback, the observer and feedback can be obtained by solving two algebraic Riccati equations.     

Robust stabilization of uncertain systems with time-varyingmultistate delay

The authors deal with the problem of stabilizing a class of uncertain linear systems with time-varying multi-state delay and subject to norm-bounded parameter uncertainty via memoryless linear state feedback. Some sufficient conditions for the robust stabilizability are derived fur this class of uncertain systems. If there exists a positive-definite symmetric solution satisfying the algebraic Riccati equation (or inequality), a suitable memoryless state feedback law can be derived also. Moreover, all such parametric algebraic Riccati inequalities have been transformed into some linear matrix inequality problems, so there is no tuning of the parameters to gain a stabilizing solution     

A study of robust controller and observer design method for a rolling object and beam system

This paper deals with a robust control problem for a ball and beam system with an uncertainty. At first, we clarify the effect of a measurement error in the beam rotational angle and its differential value. It is expressed as additional terms in the state and input matrix of the state equation, which is called as a structured uncertainty. For this system, a robust tracking controller and a robust state observer are applied. Both components are designed based on a robust control, which is called guaranteed cost control. This is a kind of cost minimization method for designing problem of a linear feedback system. The controller is obtained as the solution of the matrix algebraic Riccati like equation, which is referred to as stochastic algebraic Riccati equation. The nominal system performance is degraded due to the influence of the uncertainty, but it is able to design a system with robustness for disturbance. Next, we consider the design problem of a state observer to estimate all state variables form the output signal easy to measure, like rotation angle of the beam. For the design problem of the state observer, we consider dual problem of the original system. Consequently, our proposed system estimates the whole state vector, and using estimated state values, it controls the ball to the desired position. Both components have robustness for the uncertainty. Numerical result shows the validity of our proposed method.     

Characterizing all optimal controls for an indefinite stochasticlinear quadratic control problem

This paper is concerned with a stochastic linear quadratic (LQ) control problem in the infinite-time horizon, with indefinite state and control weighting matrices in the cost function. It is shown that the solvability of this problem is equivalent to the existence of a so-called static stabilizing solution to a generalized algebraic Riccati equation. Moreover, another algebraic Riccati equation is introduced and all the possible optimal controls, including the ones in state feedback form, of the underlying LQ problem are explicitly obtained in terms of the two Riccati equations     

High-gain observer approach to disturbance attenuation using measurement feedback

A procedure is developed for disturbance attenuation in a linear system via the use of measurement feedback. A high-gain observer is used to recover the disturbance attenuation properties asymptotically, which can be achieved using full state feedback. It is thus shown that the problem of disturbance attenuation via measurement feedback can be decomposed into two problems of disturbance attenuation via state feedback. These problems of disturbance via state feedback can then be solved using existing methods based on the algebraic Riccati equation.     

H∞状态反馈控制及其最优解的探讨

本文研究了状态完全可得时Ｈ＾∞状态反馈控制问题，给出了基于一个代数Ｒｉｃｃａｔｉ方程的Ｈ＾∞状态反馈控制问题的次优解，并对一种特殊情况提出了求最优解的解析方法。     

Disturbance attenuation andH^{∞}optimization: A design method based on the algebraic Riccati equation

This note presents a method for designing a state feedback control law to reduce the effect of disturbances on the output of a given linear system. The problem under consideration involves attenuating the disturbances to a prespecified level. The construction of the state feedback control law requires the solution of a certain algebraic Riccati equation. By applying the procedure with successively smaller values of the prespecifled disturbance level, the result also provides an approach to theH^{infty}optimization problem for the state feedback case.     

A dynamic games approach to controller design: disturbancerejection in discrete-time

It is shown that the discrete-time disturbance rejection problem, formulated in finite and infinite horizons, and under perfect state measurements, can be solved by making direct use of some results on linear-quadratic zero-sum dynamic games. For the finite-horizon problem an optimal (minimax) controller exists, and can be expressed in terms of a generalized (time-varying) discrete-time Riccati equation. The existence of an optimum also holds in the infinite-horizon case, under an appropriate observability condition, with the optimal control, given in terms of a generalized algebraic Riccati equation, also being stabilizing. In both cases, the corresponding worst-case disturbances turn out to be correlated random sequences with discrete distributions, which means that the problem (viewed as a dynamic game between the controller and the disturbance) does not admit a pure-strategy saddle point. Results for the delayed state measurement and the nonzero initial state cases are presented