方波型无刷直流电机的跟踪控制及扰动衰减

针对含随机扰动的方波型无刷直流电机的电压跟踪,引入饱和向量值函数及自适应参数,设计一种简单的、含饱和项的自适应非线性控制器克服电压跟踪中出现的电压饱和现象及抑制随机扰动,使受控系统跟踪参考电压信号．从理论上论证受控系统在设计的控制器作用下是全局一致毕竟有界．数值实验显示该控制器能使受控系统实现扰动衰减,电压跟踪效果较好．     

线性不确定时滞系统混杂反馈H ∞鲁棒镇定

利用混杂反馈控制策略研究一类线性不确定时滞系统H∞鲁棒镇定问题．分别利用单Lyapunov函数方法和多Lyapunov函数方法给出了控制器的两种切换方案，这两种方案都能保证线性不确定时滞系统的镇定和H∞扰动衰减度，并由两个耦合的线性矩阵不等式的解给出了两个静态状态反馈H∞控制器的设计．     

带有持续扰动非线性系统的前馈- 反馈最优控制

研究具有外界持续扰动作用下非线性系统的最优控制问题，提出了一种设计前馈一反馈最优控制器的逐次逼近算法．利用该算法可将在扰动作用下的非线性系统的最优控制问题转化为求解线性非齐次两点边值序列的问题．得到的最优控制律由解析的线性前馈-反馈项和伴随向量序列极限形式的非线性补偿项组成．通过截取非线性补偿序列的有限项，可得到前馈-反馈次优控制律．仿真结果表明，该方法抑制外部持续扰动的鲁棒性优于经典反馈最优控制．     

基于结构化闭环响应和输出方差限制的控制器性能评价

对于多扰动动态下的线性时不变控制器的性能评价进行了研究．针对系统具有多个扰动动态的情况， 提出了一种新的控制器性能评价方法．这一方法构建了一个加权的性能指标，权值与不同扰动的种类和优先级相对 应．同时该方法可以明确计算出各个扰动的结构闭环输出方差的下限值．通过为不同的扰动选取适当的权值和方差 范围，可以计算得出最优的输出方差．将这一最优方差值作为基准就可以评价实际生产系统的控制性能．仿真例子 表明了该方法的有效性．     

基于误差空间的鲁棒跟踪控制

为精确跟踪参考输入信号、抑制扰动信号，将输入信号和扰动信号满足的方程作为问题公式的一部分，在误差空间中设计鲁棒跟踪控制器；并加入前馈控制，改善系统的动态性能，提高系统抑制扰动的能力，使系统能以零稳态误差跟踪非衰减输入，零稳态误差抑制非衰减扰动，并在某些参数变化的情况下能准确跟踪输入信号．仿真结果表明系统具有很强的鲁棒性、优良的动态性能和稳态性能．     

脉冲负载下的永磁同步电机随机扰动衰减研究

针对随机扰动及脉冲负载下的永磁同步电机速度跟踪控制问题,利用脉冲系统的稳定性理论,对以电机转速和负载为状态变量的脉冲系统进行分析,获得系统的稳定性结论。理论分析获证,受控系统在控制器作用下是李亚普诺夫稳定的,并能实现扰动衰减。数值实验表明,所获控制方案能有效抑制系统的随机扰动以及脉冲负载扰动,系统输出跟踪能力强。     

基于LMI的不确定切换系统极点配置

研究了一类不确定线性切换系统基干状态反馈的援点配置和LMI方法问题。此类切换系统不仅具有未知但有界的结构不确定性,而且具有外部扰动。利用公共Lyapunov函数,得到一稳定切换控制策略来保证:(1)备线性子系统的特征值位于左半复平面的选定圆内,(2)最小化闭环切换系统的扰动衰减水平。在各子系统不稳定的前提下,设计切换系统的状态反馈控制器,使得在任意切换策略下系统的闭环极点配置在左半复平面,且具有良好的扰动衰减水平,系统渐近稳定。得到了切换系统可状态反馈镇定的充分条件,然后用易于求解的线性矩阵不等式形式表示出结果;最后通过仿真验证所设计的切换系统在状态反馈控制器下渐近稳定,且具有良好的投点配置和最小γ衰减水平。     

一类非线性切换系统鲁棒H∞可靠控制

为了克服扰动与执行器故障对控制系统的影响，使系统具有抗干扰性和可靠性，针对一类不确定非线性切换系统，研究了在任意切换规则下鲁棒H∞可靠控制问题．首先，系统所有矩阵同时含有参数不确定性，并且系统也存在未知非线性扰动．当执行器存在故障时，基于线性矩阵不等式技术以及公共李亚普诺夫函数方法得到鲁棒H∞可靠控制器，使切换系统在任意切换律下全局二次稳定并且满足H∞性能指标．最后，通过求解凸优化问题得到了鲁棒H∞最优可靠控制器．仿真结果表明控制器在任意切换规则下是可行和有效的．     

丢包网络化控制系统非脆弱量化H∞控制

针对非线性网络化控制（NCS）系统中控制器参数存在摄动的问题,考虑传感器—控制器和控制器—执行器均存在随机丢包和量化误差,提出了一种加性非脆弱量化H_∞控制器的设计方法．利用李亚普诺夫稳定性理论和线性矩阵不等式（LMI）方法,将该问题转化为线性矩阵不等式约束和线性目标函数的凸优化问题进行求解,给出了丢包下的非脆弱量化H_∞控制器存在的充分条件．所设计的控制器在容许的参数摄动、丢包概率和量化密度条件下,不仅能保证闭环NCS的稳定性和性能要求,而且是非脆弱的．数值仿真验证了所提方法的有效性．     

有数据包丢失奇异网络控制系统H_∞控制器设计

针对广泛存在于许多领域和行业的奇异被控系统模型,考虑网络控制环境下存在的网络诱导时延、数据包丢失、外部扰动、奇异系统结构不稳定性和脉冲行为等复杂因素,利用Lyapunov和线性矩阵不等式方法,研究了状态反馈控制方式下奇异网络控制系统H!控制器设计和优化问题,提出了奇异网络控制系统状态反馈H!控制器存在的条件、H!控制器设计及其优化方法以及相应的扰动衰减度求取方法。系统仿真实例表明了提出的设计方法有效且可行。     

Improved disturbance rejection for predictor-based control of MIMO linear systems with input delay

In this paper, we are concerned with the predictor-based control of multi-input multi-output (MIMO) linear systems with input delay and disturbances. By taking the future values of disturbances into consideration, a new improved predictive scheme is proposed. Compared with the existing predictive schemes, our proposed predictive scheme can achieve a finite-time exact state prediction for some smooth disturbances including the constant disturbances, and a better disturbance attenuation can also be achieved for a large class of other time-varying disturbances. The attenuation of mismatched disturbances for second-order linear systems with input delay is also investigated by using our proposed predictor-based controller.     

IQC-based -control of linear periodic systems

Stability analysis of linear periodically time-varying systems via integral quadratic constraints is extended to the problem of control design. A full-state feedback controller that satisfies exponential stability and -gain disturbance attenuation from an external disturbance to a controlled output is designed for linear systems with periodically time-dependent system matrices. The main result relies on dual forms of certain integral quadratic constraints. The solvability conditions for the problem are cast as a set of finite-dimensional linear matrix inequalities and thus, they are easily solvable. Moreover, the best possible disturbance attenuation level can be obtained as a convex problem.     

Disturbance attenuation by dynamic output feedback for input-delay systems

This paper addresses the optimal disturbance attenuation problem by output feedback for multivariable linear systems with delayed inputs. The attenuation is optimal in the sense that the controller minimizes the maximal amplitude of the plant output in response to such a disturbance. The controller is a general feedback, involving an observer, a state predictor, and a predicted state feedback. The optimal disturbance attenuation problem is formulated in terms of an equivalent system without delay. The optimal bound of the disturbance attenuation is then characterized, and it is shown that the optimal controller tends to have high gains. A necessary and sufficient condition to guarantee the existence of an optimal solution is provided using the geometric approach.     

H ∞ Control for uncertain system with time-delay and nonlinear external disturbance via adaptive control method

This paper considers the H _∞ control problem for the uncertain time delay system with nonlinear external disturbance. Given a system containing nonlinear external disturbance, our purpose is to design a robust controller such that the uncertain system is asymptotically stable with a generalized H _∞ disturbance attenuation level ρ. In this paper we propose a new approach to design the controller for the uncertain system which is composed of a linear controller and an adaptive controller. The problem is solved by introducing a switching function and using the idea of formulation. Based on Lyapunov stability theory, new sufficient conditions are obtained in terms of linear matrix inequalities. The effectiveness and advantages of the proposed controller design are shown via a numerical example.     

STABILITY AND H∞ DISTURBANCE ATTENUATION ANALYSIS FOR LTI CONTROL SYSTEMS WITH CONTROLLER FAILURES

In this paper, we analyze stability and H_∞ disturbance attenuation properties for linear time‐invariant (LTI) systems controlled by a pre‐designed dynamical output feedback controller which fails from time to time due to physical or purposeful reasons. Our aim is to find conditions concerning the controller failure time, under which the system's stability and H_∞ disturbance attenuation properties are preserved to a desired level. For stability, by using a piecewise Lyapunov function, we show that if the unavailability rate of the controller is smaller than a specified constant and the average time interval between controller failures (ATBCF) is large enough, then the global exponential stability of the system is guaranteed. For H_∞ disturbance attenuation, also by using a piecewise Lyapunov function, we show that if the unavailability rate of the controller is smaller than a specified constant, then a system with an ATBCF achieves a reasonable weighted H_∞ disturbance attenuation level, and the weighted H_∞ disturbance attenuation approaches normal H_∞ disturbance attenuation when the ATBCF is sufficiently large.     

广义系统的时滞相关非脆弱H_∞保成本控制

研究了时滞不确广义系统的时滞相关非脆弱H∞保成本控制器的设计问题。利用Lyapunov的稳定性理论和最近建立的积分不等式方法,得到了时滞不确定广义系统在非脆弱控制器作用下不仅内部渐近稳定,而且具有给定的H∞扰动抑制水平的时滞相关条件,以及相应的成本函数上界。假定其中的不确定项是范数有界的,但不需要满足严格的匹配条件.针对控制器增益具有加法式摄动和乘法式摄动两种情形,分别给出了非脆弱H∞保成本控制器的设计方法。这一方法不需要参数调节,利用Matlab的LMI工具箱求解方便。最后,数值仿真实例说明了所给方法的有效性。     

一类不确定线性时滞系统的输出反馈鲁棒H∞ 控制

研究具有防射参数不确定性的线性时滞系统的鲁棒H∞输出反馈控制器设计问题,得到了一些二次矩阵不等式,证明了如果它们有解,则从它们的解可以构造全阶严格真动态输出反馈控制器,它能保证闭环系统二次稳定且具有H∞范数意义下的干扰抑制能力,进一步证明了在某些情况下,这些二次矩阵不等式可以化为线性矩阵不等式来求解。     

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.     

小型无人直升机的模型预测控制算法研究

针对无人直升机在阵风干扰环境中的姿态控制精度低的问题.本文将非线性刚体动力学模型在悬停点应用小扰动理论得到了线性化数学模型.考虑系统输入输出和控制量约束,采用模型预测控制将控制器的设计问题转化为每个采样时刻求解一个带不等式和等式约束的凸二次规划问题.通过设计终端状态约束解决了有限时域模型预测控制(model predictive control, MPC)算法的稳定性问题,并通过引入松弛变量使得约束优化问题更容易求解.随机和常值阵风干扰下无人机悬停仿真验证了本文MPC预测控制器具有幅度不超过0.25 m/s的良好干扰抑制能力,性能明显优于线性二次型调节器(linear-quadratic regulator, LQR).     

H∞-optimal control for singularly perturbedsystems. II. Imperfect state measurements

For pt.I, see ibid., vol. 29, no. 2, p 401-423 (1993). In this paper we study the H^∞-optimal control of singularly perturbed linear systems under general imperfect measurements, for both finite- and infinite-horizon formulations. Using a differential game theoretic approach, we first show that as the singular perturbation parameter (say, ϵ>0) approaches zero, the optimal disturbance attenuation level for the full-order system under a quadratic performance index converges to a value that is bounded above by (and in some cases equal to) the maximum of the optimal disturbance attenuation levels for the slow and fast subsystems under appropriate “slow” and “fast” quadratic cost functions, with the bound being computable independently of E and knowing only the slow and fast dynamics of the system. We then construct a controller based on the slow subsystem only and obtain conditions under which it delivers a desired performance level even though the fast dynamics are completely neglected. The ultimate performance level achieved by this “slow” controller can be uniformly improved upon, however, by a composite controller that uses some feedback from the output of the fast subsystem. We construct one such controller, via a two-step sequential procedure, which uses static feedback from the fast output and dynamic feedback from an appropriate slow output, each one obtained by solving appropriate ϵ-independent lower dimensional H^∞-optimal control problems under some informational constraints. We provide a detailed analysis of the performance achieved by this lower-dimensional ϵ-independent composite controller when applied to the full-order system and illustrate the theory with some numerical results on some prototype systems