Active disturbance rejection control based on weighed-moving-average-state-observer

In this work, we are concerned with the boundary stabilization of a one-dimensional anti-stable wave equation corrupted by a boundary disturbance. We firstly propose, by weighed moving average technique, a state observer to make an estimation of the disturbance. Secondly, we design a control by the active disturbance rejection strategy to stabilize the system.     

Optimal disturbance rejection control for nonlinear impulsive dynamical systems

In this paper, we develop an optimality-based framework for addressing the problem of nonlinear–nonquadratic hybrid control for disturbance rejection of nonlinear impulsive dynamical systems with bounded exogenous disturbances. Specifically, we transform a given nonlinear–nonquadratic hybrid performance criterion to account for system disturbances. As a consequence, the disturbance rejection problem is translated into an optimal hybrid control problem. Furthermore, the resulting optimal hybrid control law is shown to render the closed-loop nonlinear input–output map dissipative with respect to general supply rates. In addition, the Lyapunov function guaranteeing closed-loop stability is shown to be a solution to a steady-state hybrid Hamilton–Jacobi–Isaacs equation and thus guaranteeing optimality.     

Simultaneous uniform disturbance rejection and decoupling for nonsquare linear time-dependent analytic systems using restricted state feedback

In this paper, we consider, for the first time, the combinedproblem of uniform disturbance rejection and decoupling of nonsquarelinear time-dependent analytic systems via restricted staticstate feedback. The problem is treated on the basis of an algebraicapproach, whose main feature is that it reduces the problemto that of solving a homogeneous algebraic system of equations.On the basis of this fundamental system of equations, necessaryand sufficient conditions of a simple algebraic nature are derivedfor the existence of a restricted static state-feedback controllerthat rejects the disturbances and simultaneously decouples theclosed-loop system. Furthermore, simple expressions for a specialadmissible controller pair are derived analytically.     

A numerical solution for the simultaneous disturbance decoupling and row-by-row decoupling problem

The numerical computation of the simultaneous disturbance decoupling and row-by-row decoupling problem is considered. Based on a condensed form for the system matrices the solvability of the simultaneous disturbance decoupling and row-by-row decoupling problem is reduced to the verification of an integer equality and the nonsingularity of a lower-dimensional constant matrix. The condensed form we use is computed using only orthogonal transformations, which can be implemented in a numerically stable way. Hence, it leads directly to an effective numerical method for solving the disturbance decoupling and row-by-row decoupling problem using existing tools such as LAPACK and Matlab. Our result complements existing geometric and structural approaches which are of a theoretical nature and are not suitable for numerical computation.     

Multivariable adaptive variable structure disturbance rejection control for DFIG system

A novel variable structure and disturbance rejection control strategy for a wind turbines equipped with a double fed induction generator based on stator‐flux‐oriented vector control is presented. According to estimation of maximum power operation points of wind turbine under stochastic wind velocity profiles and tracking them using traditional offline gain, scheduling and innovative adaptive online method is necessary. To demonstrate the effectiveness of the proposed control strategy, the estimation of maximum operating power point of wind turbine and tracking it under stochastic wind velocity profiles has been considered as a test case. Simulation results show the validity of the proposed technique. © 2014 Wiley Periodicals, Inc. Complexity 21: 50–62, 2016     

Reliability based optimization using a decoupling approach and reliability approximations

This contributions focuses on the solution of a reliability-based optimization (RBO) problem using an approximate representation of the structural reliability and a decoupling approach. Such strategy may lead to considerable numerical savings. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

非方广义系统带最坏干扰抑制的奇异LQ问题

研究了非方广义系统带最坏干扰抑制的奇异线性二次指标最优控制问题(即LQ问题).在给定的条件下,最坏干扰和最优控制—状态对均存在且惟一,最优控制可被综合为状态反馈.在最坏干扰和最优控制作用下,所得闭环系统的任意有限特征值均在开左半复平面,且闭环系统的状态有最少自由元.     

On some properties of the control problem under a program disturbance in a formalization based on the minimax risk (regret) criterion

A control problem under uncertainty for a system described by an ordinary differential equation with a terminal performance index is considered. The control and disturbance are subject to geometric constraints. The problem is formalized in classes of nonanticipating control strategies and program disturbances with the use of constructive ideal motions and the Savage minimax risk (regret) criterion. The properties of the used motion bundles are described and a number of relations characterizing the optimal risk function, which is an element of the formalization, are presented.     

Inventory control with Markovian capacity and the option of order rejection

We consider a stochastic inventory control problem with Markovian capacity and the option of order rejection. We show its optimal policy to be the combination of a capacity-dependent modified base-stock production policy and a capacity-dependent critical-point order acceptance policy. When capacity is stochastically monotone, we show that the policy parameters change over the current capacity level in an intuitive way. All these results can be extended to the infinite-horizon case, with or without cost discounting. Our computational study substantiates the benefits from both exploiting the Markovian behavior of the capacity and rejecting orders when necessary.     

Actuator placement based on reachable set optimization for expected disturbance

This paper examines the role of the control objective and the control time in determining fuel-optimal actuator placement for structural control. A general theory is developed that can be easily extended to include alternative performance metrics such as energy and timeoptimal control. The performance metric defines a convex admissible control set which leads to a max-min optimization problem expressing optimal location as a function of initial conditions and control time. A solution procedure based on a nested genetic algorithm is presented and applied to an example problem. Results indicate that the optimal placement varies widely as a function of both control time and disturbance location. An approximate fitness function is presented to alleviate the computational burden associated with finding exact solutions. This function is shown to accurately predict the optimal actuator locations for a 6th-order system, and is further demonstrated on a 12th-order system.This work was supported by the US Department of Energy at Sandia National Laboratories under Contract DE-AC04-76DP00789.     

Finite-time control of discrete-time systems with time-varying exogenous disturbance

This paper deals with some finite-time control problems for uncertain discrete-time linear systems subject to exogenous disturbance. Sufficient conditions are presented for finite-time stabilization via state feedback. These conditions can be reduced to feasibility problems involving linear matrix inequality (LMI). A detailed solving method is proposed for the restricted linear matrix inequalities. Finally, an example illustrates the proposed methodology.     

Uniform stabilization of the wave equation with Dirichlet or Neumann feedback control without geometrical conditions

In this paper we eliminate altogether geometrical conditions that were assumed (even) with control action on the entire boundary in prior literature: (i) strict convexity of our paper [LT4] on uniform stabilization of the wave equation in the (optimal) state spaceL ₂()×H ^–1() withL ₂() Dirichlet feedback control, as well as (ii) star-shaped conditions in papers [C1], [La1], and [Tr1] on uniform stabilization and [Lio1] and [LT5] on exact controllability in the energy spaceH ¹()×L ₂() of the wave equation withL ₂()-Neumann feedback control. Key to the present improvements is a pseudodifferential analysis which permits us to express certain boundary traces of the solution in terms of other traces modulo lower-order interior terms. See Lemma 3.1 for the Dirichlet case and Lemma 7.2 for the Neumann case.This research was partially supported by National Science Foundation under Grant DMS-8902811 and by Air Force Office of Scientific Research under Grant AFOSR-87-0321. This paper was presented by R. Triggiani at the Decision and Control Conference held in Tampa, Florida, December 1989. A preliminary version has appeared in the Proceedings of the Third Working Conference, Montpellier, France, January 1989 (J. P. Zolésio, Editor), Lecture Notes in Control and Information Sciences, Vol. 147, Springer-Verlag, Berlin, pp. 62–108.     

基于部件指派的多状态系统可靠度优化研究

针对一般二态系统假设的不足,提出了多状态系统条件下的可靠度优化指派问题。该问题以系统可靠度最大化为优化目标,在考虑部件分配成本和总分派成本预算的前提下,对多状态系统下不同状态对应的性能水平的进行了分析,给出了基于通用生成函数的多状态系统的可靠度评估方法。根据指派问题的组合优化的特性和多状态系统可靠性评估的特点,对传统遗传算法的适应度函数进行了改进,设计了基于整数编码的遗传算法,该算法具有离散变量的设计灵活性和强大的搜索性能。算例实验表明,本文设计的优化算法具有较好的求解质量,同时算法的运行时间也得到了大幅的缩短。本研究为多状态系统的可靠度优化提供了一条可借鉴的思路。     

基于Vague集思想的电子产品可靠性评价

针对电子产品可靠性评价中存在的问题,将Vague集理论引入到评价环节.通过指标选取、权重确定、Vague加权集结、记分函数计算等四个环节的计算,剔除了可靠性评价中的不确定性信息.方法体现了Vague集理论描述不确定性问题的优点,反映了电子产品可靠性评价的一般特点,得到了公平公正的评价结果,方法的应用具有一定推广价值.     

基于Kullback信息融合方法的串联系统可靠性评估

讨论了串联系统在具有多源验前信息的情形下的可靠性评估问题,运用K u llback信息作为分布之间距离的度量,在K u llback信息的融合准则下对多个先验分布进行融合.并以融合后的先验分布作为系统的最终验前分布,对串联系统的可靠性指标进行Bayes估计.最后进行的计算机随机模拟结果表明,文中所提出的方法合理且便于应用.