含时滞的不确定性交直流微电网直流母线电压H_∞控制

针对含通信网络延时的不确定性交直流微电网的直流母线电压稳定问题,提出了一种将状态空间法和阻抗分析法相融合的方法,构建具有时滞的范数有界不确定交直流微电网模型。基于系统鲁棒二次稳定的求解,获得了满足H_∞控制性能的时滞无关型状态反馈控制器的条件。然后应用S-procedure定理,提出一种降低时滞依赖型Lyapunov方法的泛函构造难度且无须再次求导的方法,引用Wirtinger积分不等式和自由矩阵的积分不等式,得到时滞依赖型的H_∞控制器。仿真分析验证了所提控制方法能在一定的通信延时约束下抑制不确定参数对直流母线电压的影响。

Robust and Non-fragile H_∞ Control for a Class of Uncertain Jump Linear Systems

This paper describes the synthesis of robust and non-fragile H∞ state feedback controllers for a class of uncertain jump linear systems with Markovian jumping parameters and state multiplicative noises. Under the assumption of a complete access to the norm-bounds of the system uncertainties and controller gain variations, sufficient conditions on the existence of robust stochastic stability and γ-disturbance attenuation H∞ property are presented. A key feature of this scheme is that the gain matrices of controller are only based on It, the observed projection of the current regime rt.

Non-fragile decentralized H_∞ controller design for uncertain linear systems

Considering the design problem of non-fragile decentralized H∞ controller with gain variations, the dynamic feedback controller by measurement feedback for uncertain linear systems is constructed and studied. The parameter uncertainties are considered to be unknown but norm bounded. The design procedures are investigated in terms of positive definite solutions to modify algebraic Riccati inequalities. Using information exchange among local controllers, the designed non-fragile decentralized H∞ controllers guarantee that the uncertain closed-loop linear systems are stable and with H∞ -norm bound on disturbance attenuation. A sufficient condition that there are such non-fragile H∞ controllers is obtained by algebraic Riccati inequalities. The approaches to solve modified algebraic Riccati inequalities are carried out preliminarily. Finally, a numerical example to show the validity of the proposed approach is given.

四旋翼悬挂负载系统预设有限时间H_∞容错控制

在实际飞行中,四旋翼飞行器悬挂负载系统容易受到负载摆动以及外部扰动的影响,且可能出现执行器故障。针对此问题,本文基于反步法设计有界H_(∞)容错控制器来抑制外部扰动并消除执行器故障的影响,利用神经网络逼近系统中负载的不确定性,同时引入预设有限时间性能函数,使得四旋翼飞行器即使在负载和外部扰动的影响下,其跟踪误差仍能被约束在预先给定的范围内。所设计的控制器能够保证系统在较精确地跟踪参考轨迹的同时具有较高的抗干扰性能。仿真验证了所设计的控制器的有效性。

Design of robust non-fragile H-infinity controllerbased on Delta operator theory

Considering that the controller parameters are of additive norm-bounded uncertainties when realized, a design method of robust non-fragile H-infinity controller for uncertain systems based on Delta operator theory is illustrated in this paper. A sufficient and necessary condition of the existence for the controller is given, which is presented in LMI forms. Finally, the designed method is used in the speed control system of a permanent magnet linear synchronous motor （PMLSM）. With the designed controller, the resulting speed closed-loop system is still stable and has the expected Hinfinity performance even if the sample period is reduced and the parameters of the controller and the controlled object are varied. The results show that the designed method is effective.

Non-fragile observer-based passive control for descriptor systems with time-delay

This paper investigates the problem of non-fragile observer-based passive control for descriptor systems with time-delay. The perturbations in both the control gain and observer gain of the observer-based controller are considered. For the cases of the additive perturbations and multiplicative perturbations, sufficient conditions are given such that the closed-loop systems are admissible and passive with dissipation η. The observer-based controller gains could be obtained from the solutions of linear matrix inequalities （LMIs）. Moreover, the maximum dissipation of the system is provided. Simulation examples are given to show the effectiveness of the deign methods.

A novel mixed-synchronization phenomenon in coupled Chua's circuits via non-fragile linear control

Dynamical variables of coupled nonlinear oscillators can exhibit different synchronization patterns depending on the designed coupling scheme. In this paper, a non-fragile linear feedback control strategy with multiplicative controller gain uncertainties is proposed for realizing the mixed-synchronization of Chua＇s circuits connected in a drive-response configuration. In particular, in the mixed-synchronization regime, different state variables of the response system can evolve into complete synchronization, anti-synchronization and even amplitude death simultaneously with the drive variables for an appropriate choice of scaling matrix. Using Lyapunov stability theory, we derive some sufficient criteria for achieving global mixed-synchronization. It is shown that the desired non-fragile state feedback controller can be constructed by solving a set of linear matrix inequalities （LMIs）. Numerical simulations are also provided to demonstrate the effectiveness of the proposed control approach.

Non-fragile state feedback H-infinity control for discrete-time systems with quantized signals

This paper presents a study on the problem of non-fragile state feedback H-infinity controller design for linear discrete-time systems with quantized signals. The quantizers considered here are dynamic and time-varying. With the consideration of controller gain variations and quantized signals at the same time, a new non-fragile H-infinity control strategy is proposed with updating quantizer＇s parameters, such that the quantized closed-loop system is asymptotically stable and with a prescribed H-infinity performance bound. An example is presented to illustrate the effectiveness of the proposed control strategy.

Non-fragile hybrid guaranteed cost control for a class of uncertain switched linear systems

This paper focuses on the problem of non-fragile hybrid guaranteed cost control for a class of uncertain switched linear systems. The controller gain to be designed is assumed to have additive gain variations. Based on multiple-Lyapunov function technique, the design of non-fragile hybrid guaranteed cost controllers is derived to make the corresponding closed-loop system asymptotically stable for all admissible uncertainties. Furthermore, a convex optimization approach with LMIs constraints is introduced to select the optimal non-fragile guaranteed cost controllers. Finally, a simulation example illustrates the effectiveness of the proposed approach.

Delay-dependent Non-fragile H_∞ Filtering for Uncertain Fuzzy Systems Based on Switching Fuzzy Model and Piecewise Lyapunov Function

This paper is concerned with the non-fragile H∞ filter design problem for uncertain discrete-time Takagi-Sugeno （T-S） fuzzy systems with time delay. To begin with, the T-S fuzzy system is transformed to an equivalent switching fuzzy system. Then, based on the piecewise Lyapunov function and matrix decoupling technique, a new delay-dependent non-fragile H∞ filtering method is proposed for the switching fuzzy system. The proposed condition is less conservative than the previous results. Since only a set of LMIs is involved, the filter parameters can be solved directly. Finally, a design example is provided to illustrate the validity of the proposed method.

Robust Non-fragile PID Controller Design for the Stroke Regulation of Metering Pumps

这个工作准时集中高精确的 metering 泵的一个班的规定。柔韧的非易碎的 PID (proportional-integral-derivative ) 控制器的一个调节参数的方法与假设被建议一个 PID 控制器有添加剂获得不安。一个 H 无限的柔韧的 PID 控制器能被解决线性矩阵不平等获得。这条途径靠近环的控制系统是 asymptotically 稳定的保证和转移的 H 无限的标准能从骚乱工作到一个控制系统的输出不到稀释骚乱的一个给定的常数。建议策略的控制表演比传统的 PID 显著地好的模拟盒子表演与控制器参数的不安处于状况来临。

Non-fragile Dynamic Output Feedback H∞Control for a Class of Un­certain Switched Systems with Time-varying Delay

The problem of non-fragile dynamic output feedback H∞control for a class of uncertain switched systems with time-varying delay is discussed.Firstly,the form of non-fragile dynamic output feedback H∞controller is given.Under the condition that the upper bound of time delay and the upper bound of delay derivative are limited simultaneously,Lyapunov functional and its corresponding switching rules are constructed by using single Lyapunov function method and convex combination technique;Secondly,we use the inequality lemma to scale the derived Lyapunov functional in order to eliminate the time-varying delay term in the in­equality,and then introduce the J-function to obtain a nonlinear matrix in­equality that satisfies the H∞performance indexγ,we also employ Schur complement lemma to transform the nonlinear matrix inequality into set of linear matrix inequalities consisting of two linear matrix inequalities,a sufficient condition for the existence of a non-fragile dynamic output feedback H∞controller and satisfying the H∞performance indexγis concluded for a class of uncertain switching systems with variable time delay;Finally,a switched system composed of two subsystems is consid­ered and the effectiveness and practicability of the theorem are illustrated by numerical simulation with LMI toolbox.

Non-Fragile Controller Design for 2-D Discrete Uncertain Systems Described by the Roesser Model

This paper is concerned with the design problem of non-fragile controller for a class of two-dimensional (2-D) discrete uncertain systems described by the Roesser model. The parametric uncertainties are assumed to be norm-bounded. The aim of this paper is to design a memoryless non-fragile state feedback control law such that the closed-loop system is asymptotically stable for all admissible parameter uncertainties and controller gain variations. A new linear matrix inequality (LMI) based sufficient condition for the existence of such controllers is established. Finally, a numerical example is provided to illustrate the applicability of the proposed method.

Robust Non-Fragile Control of 2-D Discrete Uncertain Systems: An LMI Approach

This paper considers the problem of robust non-fragile control for a class of two-dimensional (2-D) discrete uncertain systems described by the Fornasini-Marchesini second local state-space (FMSLSS) model under controller gain variations. The parameter uncertainty is assumed to be norm-bounded. The problem to be addressed is the design of non-fragile robust controllers via state feedback such that the resulting closed-loop system is asymptotically stable for all admissible parameter uncertainties and controller gain variations. A sufficient condition for the existence of such controllers is derived based on the linear matrix inequality (LMI) approach combined with the Lyapunov method. Finally, a numerical example is illustrated to show the contribution of the main result.

具有介质访问约束的网络化控制系统H∞状态估计

研究了一类存在介质访问约束和信号量化的网络化控制系统的H∞状态估计问题。首先,考虑到介质访问约束和信号量化的影响,将信号量化误差转化为扇形有界的不确定性,对由于访问约束而未获得网络传输的系统输出采用加权补偿策略,根据网络介质的随机访问机制将网络化系统建模为具有不确定性的马尔可夫跳跃系统。然后,在此基础上借助李雅普诺夫稳定性理论和H∞性能约束条件,利用线性矩阵不等式(linear matrix inequality,LMI)方法给出状态估计器存在的充分条件,所设计的状态估计器使得估计误差系统渐近稳定且具有给定的H∞性能。最后,通过仿真实例验证了该设计方法的有效性。

基于自抗扰控制的H桥逆变器的混沌研究

为了解决新能源发电系统逆变器出现混沌的问题,提出了一种基于自抗扰控制的H桥逆变器的调节方案。针对处于混沌状态的逆变器的稳态和动态特性差的现象,构建了逆变器的离散模型,并通过建立跟踪微分器、扩张状态观测器以及状态误差反馈控制律进行混沌控制。通过分岔图、折叠图以及仿真分析,结果可知基于自抗扰控制的H桥逆变器比基于比例控制的H桥逆变器的稳定范围扩大了45%,有效地抑制了混沌现象的发生。通过分析可得出:该控制策略对系统的混沌行为能够进行抑制,拓宽了系统稳定工作范围。

带扰动补偿的永磁同步电机鲁棒H∞控制

为了提高永磁同步电机调速系统的抗干扰能力,提出了一种鲁棒H∞控制方法。首先,根据鲁棒H∞控制原理,提出了永磁同步电机H∞速度控制设计方法,并介绍了求解方法。设计加权函数时考虑了跟踪性能、干扰抑制、输出限制和模型不确定性。通过伯德图详细说明了性能加权函数对动态性能的影响,并给出了加权函数的设计方法。然后,在考虑参数不确定性和未建模动态的情况下,为进一步提高系统的抗干扰能力,通过Luenberger扰动观测器将扰动作为前馈补偿观测,并将其反馈到速度控制器中,以加速动态响应,增强对扰动的抑制能力。最后,通过试验对比了传统比例积分控制器、H∞速度控制器和所提的复合速度控制器,试验结果验证了所提复合速度控制器的有效性。

热轧H型钢生产工艺技术

简述了H型钢的发展现状及H型钢的应用特点,从轧钢工艺方面介绍了小型、中型、大型H型钢国内比较常见的几种生产方法,包括全连续、半连续以及半连续往复穿梭轧制法,并通过国内主要型钢厂的实例,对几种轧制方法进行阐述。同时介绍了国内H型钢未来的发展趋势及新技术的应用。

H_∞ Consensus Control of Discrete-Time Multi-Agent Systems Under Network Imperfections and External Disturbance

This paper presents a distributed control protocol for consensus control of multi-agent systems(MASs) under external disturbances and network imperfections, including communication delay and random packet dropout. To comply with the discrete nature of networked systems, in contrast to most of the existing work for MASs under network imperfections,the agents are modeled by discrete-time dynamics. The communication network is considered to be undirected, its delay is considered to be time-varying but bounded, and its packet dropout is modeled by a Bernoulli distributed white sequence.Sufficient conditions in terms of linear matrix inequalities(LMIs)for asymptotic mean-square consensus stability are derived under network imperfections without considering external disturbances.A desired disturbance attenuation level in the presence of both external disturbances and network imperfections is also provided.A simulation example is given to verify the effectiveness of the proposed approach in coping with network imperfection and disturbances.

Distributed H_∞ control of multi-agent systems with directed networks

This paper studies the distributed H∞control problem of identical linear time invariant multi-agent systems subject to external disturbances. A directed graph containing a spanning tree is used to model the communication topology. Based on the relative states of the neighbor agents and a subset of absolute states of the agents, distributed static H∞controllers are proposed. The concept of an H∞performance region is extended to the directed graph situation. Then the results are used to solve the leader–follower H∞consensus problem. Sufficient conditions are proposed based on bounded real lemma and algebraic graph theory. The effectiveness of the theoretical results is illustrated via numerical simulations.