基于动态补偿的矩形广义系统线性二次最优控制

考虑了基于动态补偿的矩形广义系统线性二次最优控制问题. 首先给出具有适当动态阶的补偿器,使得闭环系统正则、稳定、无脉冲(称为容许), 而且相关的矩阵不等式和Lyapunov方程解存在. 进一步二次性能指标可写成一个与该解和系统初值相关的表达式. 为了求解系统的最优控制问题, 将该Lyapunov方程转化为一个双线性矩阵不等式, 并给出了相应的路径跟踪算法以最小化二次性能指标, 进而得到最优补偿器. 最后, 通过数值算例说明本文方法的有效性和可行性.     

一类不确定系统的最优极小极大鲁棒控制

讨论一类不确定系统的极小极大鲁棒动态输出反馈控制问题.给出不确定系统的极小极大鲁棒控制的定义.利用线性矩阵不等式(LMI)处理方法和Lyapunov稳定性理论,得到了在干扰和不确定性最大的情形下极小极大输出反馈控制器存在的充分条件.引入凸优化技术, 求得最优极小极大控制器.它不仅保证闭环系统渐近稳定, 且使得闭环系统性能指标的上界最小.仿真算例说明了所设计的控制器具有较强的干扰抑制功能.     

不确定离散时滞系统具有H ∞干扰抑制的保成本控制

针对一类用矩阵凸多面体形式的不确定线性离散时滞系统，提出一种通过无记忆状态反馈实现的具有H∞干扰抑制的保成本控制。当对象存在不确定性以及外部干扰统计特性未知时，该控制器能保证闭环系统稳定和一定的线性二次型性能指标上界，同时具有H∞范数下的干扰抑制作用。基于Lyapunov稳定性理论，控制器设计可转化为线性矩阵不等式的可解性问题。数值仿真表明，该控制器实际是对最优保成本上界和干扰抑制能力的一种折衷。     

带有随机跳跃干扰的线性二次随机最优控制问题

给出一类布朗运动和泊松过程混合驱动的正倒向随机微分方程解的存在唯一性结果, 应用这一结果研究带有随机跳跃干扰的线性二次随机最优控制问题,并得到最优控制的显式形 式,可以证明最优控制是唯一的.然后,引入和研究一类推广的黎卡提方程系统,讨论该方程系统 的可解性并由该方程的解得到带有随机跳跃干扰的线性二次随机最优控制问题最优的线性反馈.     

受扰非线性离散系统的前馈反馈最优控制

利用逐次逼近法研究含外部扰动的非线性离散系统的线性二次型前馈反馈最优控制问题.首先将系统的最优控制问题转化为非线性两点边值问题族.其次,构造了该问题族的由精确线性项和非线性补偿项组成的解序列,并证明了解序列一致收敛到系统的最优解.最后,通过截取最优控制序列解中非线性补偿项的有限项,得到系统的前馈反馈次优控制(FFSOC)律及设计算法.仿真算例表明,该算法容易实现,且对抑制外部扰动的鲁棒性优于经典的反馈次优控制(FSOC).     

一种网络化控制系统的鲁棒H_∞动态输出反馈控制

对于存在网络诱导控制时廷和输出时廷的网络化控制系统,在离散域内给出了网络化控制系统的一种时廷相关的动态输出反馈控制方法.针对无扰动和有扰动的系统,分别基于Lyapunov稳定性理论和线性矩阵不等式方 法,推导出闭环系统稳定的充分条件,并给出了鲁棒最优和次优控制律的设计方法.仿真结果表明,所提出方法能实 现稳定控制和有效的干扰抑制作用.     

一种网络化控制系统的鲁棒H∞动态输出反馈控制

对于存在网络诱导控制时延和输出时延的网络化控制系统,在离散域内给出了网络化控制系统的一种时延相关的动态输出反馈控制方法.针对无扰动和有扰动的系统,分别基于Lyapunov稳定性理论和线性矩阵不等式方法,推导出闭环系统稳定的充分条件,并给出了鲁棒最优和次优控制律的设计方法.仿真结果表明,所提出方法能实现稳定控制和有效的干扰抑制作用.     

多时滞不确定系统的模糊保性能H∞控制

针对多时滞不确定系统,利用T-S模型进行建模,提出了模糊保性能H∞控制问题.基于Lyapunov稳定理论,得到一种通过模糊状态反馈实现的具有干扰抑制的保性能H∞控制.当被控对象存在多时滞和不确定性及外部干扰统计特性未知时,该模糊控制器能保证闭环系统稳定和一定的二次型性能指标上界,同时具有H∞下的干扰抑制作用.控制器的设计可通过转化为线性矩阵不等式的求解问题.数值仿真表明,该控制器具有所期望设计的性能.     

基于降阶观测器的双线性系统H∞补偿器设计

讨论了多输入多输出双线性连续时间系统的基于降阶观测器的[H∞]补偿器设计问题。利用线性矩阵不等式和Lyapunov方程,得到了保证闭环系统全局渐近稳定且满足给定干扰抑制水平的bang-bang控制律的设计。仿真验证了所给理论结果的有效性。     

单输入线性系统的改进型动态抗饱和设计

本文基于状态重置的改进型动态抗饱和补偿方案, 研究了具有单输入的线性饱和系统的抗饱和控制问题. 相比较于传统的动态抗饱和补偿方案, 当执行器不饱和时, 改进的动态抗饱和补偿方案把动态抗饱和补偿器的状态重置为零. 所以当执行器不饱和时, 改进的动态抗饱和补偿器将不会对控制器进行补偿. 进一步的, 提出了一个时间依赖的Lyapunov函数来分析闭环系统的稳定性, 并以LMIs的形式给出了闭环系统的控制综合条件. 最后, 通过压电纳米运动平台验证了所提出的改进型动态抗饱和补偿方案的有效性。     

Linear quadratic regulators with eigenvalue placement in a horizontal strip

A method for optimally shifting the imaginary parts of the open-loop poles of a multivariable control system to the desirable closed-loop locations is presented. The optimal solution with respect to a quadratic performance index is obtained by solving a linear matrix Lyapunov equation.     

Optimal Output Feedback Controllers for Spacecraft Attitude Tracking

This paper investigates the problem of output feedback attitude tracking control of a rigid spacecraft in the presence of external disturbances. Two optimal control laws with a disturbance estimator are developed to deal with this problem. An adapted extended state observer is used to estimate the angular velocity tracking errors and to allow for compensation for the total disturbances. The proposed control can be expressed as the sum of a nonlinear optimal controller and an estimated disturbance. For the optimal controller, the state‐dependent Riccati equation and optimal Lyapunov techniques are employed to solve the infinite‐time nonlinear optimal control problem. The developed controllers can minimize a performance index and ensure the stability of the closed‐loop system and external disturbance attenuation. On the other hand, using the adapted extended state observer, the asymptotic convergence of estimation error dynamics is proven. An example of multiaxial attitude manoeuvres is given and simulation results are included to demonstrate and verify the usefulness of the proposed controllers.     

Controller design with regional pole constraints

A design procedure is developed that combines linear-quadratic optimal control with regional pole placement. Specifically, a static and dynamic output-feedback control problem is addressed in which the poles of the closed-loop system are constrained to lie in specified regions of the complex plane. These regional pole constraints are embedded within the optimization process by replacing the covariance Lyapunov equation by a modified Lyapunov equation whose solution, in certain cases, leads to an upper bound on the quadratic cost functional. The results include necessary and sufficient conditions for characterizing static output-feedback controllers with bounded performance and regional pole constraints. Sufficient conditions are also presented for the fixed-order (i.e. full- and reduced-order) dynamic output-feedback problem with regional pole constraints. Circular, elliptical, vertical strip, parabolic, and section regions are considered     

Piecewise Fuzzy Anti-Windup Dynamic Output Feedback Control of Nonlinear Processes With Amplitude and Rate Actuator Saturations

In this paper, a novel anti-windup dynamic output compensator is developed to deal with the robust H _infin output feedback control problem of nonlinear processes with amplitude and rate actuator saturations and external disturbances. Via fuzzy modeling of nonlinear systems, the proposed piecewise fuzzy anti-windup dynamic output feedback controller is designed based on piecewise quadratic Lyapunov functions. It is shown that with sector conditions, robust output feedback stabilization of an input-constrained nonlinear process can be formulated as a convex optimization problem subject to linear matrix inequalities. Simulation study on a strongly nonlinear continuously stirred tank reactor (CSTR) benchmark plant is given to show the performance of the proposed anti-windup dynamic compensator.     

Min-max sliding-mode control for multimodel linear time varying systems

An original linear time-varying system with unmatched disturbances and uncertainties is replaced by a finite set of dynamic models such that each one describes a particular uncertain case including exact realizations of possible dynamic equations as well as external bounded disturbances. Such a tradeoff between an original uncertain linear time varying dynamic system and a corresponding higher order multimodel system with a complete knowledge leads to a linear multi-model system with known bounded disturbances. Each model from a given finite set is characterized by a quadratic performance index. The developed min-max sliding-mode control strategy gives an optimal robust sliding-surface design algorithm, which is reduced to a solution of an equivalent linear quadratic problem that corresponds to the weighted performance indices with weights from a finite dimensional simplex. An illustrative numerical example is presented.     

一类不确定性非线性网络控制系统的扰动抑制

研究受外部持续扰动的一类不确定性非线性网络控制系统的扰动抑制问题.提出一种@状态变量代换,将控制时滞转移到闭环控制回路之外,从而消除了时滞部分对控制系统稳定性的影响.利用内模原理给出了系统无静差扰动抑制补偿器的设计方法,运用Lyapunov稳定性理论和线性矩阵不等式技术,证明了保成本控制律的存在条件,并给出了无静差保成本控制器的设计方法.仿真结果验证了该控制算法的有效性.     

广义双线性系统的最优控制

最优控制是自动控制理论的重要研究分支,本文首次对广义双线性系统的最优控制问题进行研究.利用李雅普诺夫稳定性理论和广义李雅普诺夫方程的解来设计最优控制器,使得闭环系统全局渐近稳定且使广义二次性能指标最小.此外,还给出最优化控制器的设计方法,整个设计过程简单,具有较少的保守性,例子表明设计方法的有效性和合理性.     

具有控制时滞系统的最优无静差正弦扰动抑制

研究在外部正弦扰动作用下，控制含时滞的线性系统的最优无静差调节器设计问题．首先利用Artstein变换将控制变量含时滞的系统转化为不舍时滞的系统；然后利用内模原理构造扰动补偿器，将带扰动的系统转化为无扰动的增广系统，从而将无静差扰动抑制问题转化为无扰动增广系统的最优调节器设计问题；最后利用最优控制理论求得最优无静差反馈控制律．仿真结果表明了所提出方法的有效性．     

Solvability of indefinite stochastic Riccati equations and linear quadratic optimal control problems

A new approach to study the indefinite stochastic linear quadratic (LQ) optimal control problems, which we called the “equivalent cost functional method”, is introduced by Yu (2013) in the setup of Hamiltonian system. On the other hand, another important issue along this research direction, is the possible state feedback representation of optimal control and the solvability of associated indefinite stochastic Riccati equations. As the response, this paper continues to develop the equivalent cost functional method by extending it to the Riccati equation setup. Our analysis is featured by its introduction of some equivalent cost functionals which enable us to have the bridge between the indefinite and positive-definite stochastic LQ problems. With such bridge, some solvability relation between the indefinite and positive-definite Riccati equations is further characterized. It is remarkable the solvability of the former is rather complicated than the latter, hence our relation provides some alternative but useful viewpoint. Consequently, the corresponding indefinite linear quadratic problem is discussed for which the unique optimal control is derived in terms of state feedback via the solution of the Riccati equation. In addition, some example is studied using our theoretical results.