具有不确定项的高阶非完整系统的反馈控制问题的研究

针对一类具有不确定性的高阶非完整系统,通过引入观测器,采用状态-输入转换、反推方法,设计了反馈控制器.同时为了处理初值为0的情况,提出了一种新的基于第一个子系统输出值的切换控制策略,提出的切换控制策略能有效的防止系统的状态发生有限时间逃逸现象.     

基于输出反馈的一类时滞系统鲁棒H∞容错控制

针对状态具有多个时滞的线性不确定性系统,基于李雅普诺夫稳定性理论,矩阵不等式及线性矩阵不等式方法,设计带有多个时滞记忆的输出反馈鲁棒H∞容错控制器.研究了在执行器发生故障的情况下,多时滞不确定性系统的鲁棒H∞容错控制的问题.首先给出了多个时滞记忆的输出反馈鲁棒H∞容错控制器的综合分析,进一步给出参数不确定项的多时滞系统的渐近稳定的充分条件,以及满足给定性能指标鲁棒H∞容错控制器的设计方法.仿真结果证明了该方法的有效性和可行性.     

基于快速输出采样反馈技术的无抖振离散滑模控制

针对一类单输入单输出的离散时间系统,提出了一种基于快速输出采样反馈技术(FOS)的无抖振滑模控制器.该控制策略避免了在控制器中采用切换模式,从而消除了切换面附近的抖振.理论分析和仿真结果表明该方法不仅能保证闭环系统的稳定性,而且能提高系统的稳态精度.     

线性参数变化系统的子空间预测控制

为弥补线性系统与非线性系统间的差异,考虑非线性系统的近似模型-线性参数变化系统的子空间预测控制,此控制器能更贴切地控制非线性系统.采用数据驱动的子空间预测控制策略,构造输入-输出观测数据矩阵来辨识状态空间形式下的马尔科夫参数.利用矢量积算子的数据矩阵表示将来时刻的输出预测值,并以此预测值作用于代价函数.对带有不等式约束的二次代价函数采用并行分布算法来求解其最优值.针对直流电动机在质量分布因素下的线性参数变化系统,采用子空间预测控制器来控制直流电动机.     

不确定二阶时变系统的稳定鲁棒性(英文)

首先基于系数矩阵的一致对称正定性建立了二阶线性时变系统稳定性的一个判据.该判据简单、明了,是作者早期给出的关于定常二节线性系统稳定性判据的直接推广.基于这一判据,文章进一步给出了具有参数不确定性的二阶线性时变系统的鲁棒稳定性.所得结果对于处理确定性二阶线性时变系统镇定问题和不确定性二阶线性时变系统的鲁棒镇定问题提供了便捷而有效的工具.最后,文章将提出的方法应用到某卫星姿态系统的控制中.     

磁悬浮球系统的线性自抗扰控制与参数整定

研究了磁悬浮球系统的线性自抗扰控制(linear active disturbance rejection control,LADRC)及其参数整定问题.磁悬浮系统固有的非线性、开环不稳定性、系统参数摄动和外界干扰不确定性使得传统的控制方法难以取得良好的控制效果,对象模型的不确定性又限制了最优控制等现代控制理论的有效应用.为此,文章采用LADRC实现磁悬浮球系统的控制,并利用传递函数的方法,探讨了系统动态特性与控制参数之间的关系.最后,通过仿真与实验对比LADRC与时间加权绝对误差值积分(integral time absolute error,ITAE)最优PID控制器的控制效果,结果表明LADRC在响应快速性抑制外部扰动、抑制输出噪声、对模型不确定性的鲁棒性和相位滞后等方面均优于PID控制器.     

基于动态神经网络的非线性系统鲁棒故障检测

针对一类具有不确定性扰动的非线性系统,将设计的系统线性观测器产生的误差信号作为残差,采用一种具有高斯型激励函数的动态神经网络(DNN)对残差信号进行分析处理,得到了系统的鲁棒故障检测方法.文中分析了该方法的稳定性和故障检测的鲁棒性,并通过算例验证了该方法的有效性.     

一类不确定线性周期离散时间系统的分析与控制

讨论具有参数区间不确定性的线性周期离散时间系统的反馈控制问题,首先进行系统的鲁棒稳定性分析和镇定研究,分别给出了基于线性矩阵不等式的系统渐近稳定和状态反馈镇定的条件.接着研究系统的增益分析和控制综合问题,对于增益分析问题,得到一个基于线性矩阵不等式的条件,在该条件下,具有参数不确定性的线性周期自治系统渐近稳定,且有小于γ的增益,对于控制综合问题,导出基于线性不等式的条件,由该条件可以得到一个状态反馈器,使得闭环系统渐近稳定.且有小于γ的增益,所有这些条件都是充分必要的.     

永磁同步电动机的转速跟踪控制

研究永磁同步电动机的转速控制问题.对于参数不确定,输出受限的永磁同步电动机系统,提出转速跟踪控制方法.利用神经网络逼近电动机系统中的复杂非线性函数,采用自适应控制,动态面控制技术,设计控制器实现电动机的转速跟踪控制器.文中提出的控制策略不仅能够克服电机参数的不确定性和负载扰动,而且避免了传统反步设计方法存在的"复杂性爆炸"问题.基于Lyapunov稳定性理论,证明闭环系统具有半全局稳定性,转速跟踪误差收敛于原点的极小邻域内.仿真结果验证了所提控制方法的有效性.     

一种面向可靠性的改进不确定性重要度分析方法

作为识别和评估系统薄弱环节的有效工具之一的重要度理论,一直都被广泛应用于系统可靠性和安全性工程。而作为其主要环节的不确定性重要度分析更是扮演着不可或缺的角色。因此,为有效表征多态系统的可靠性,本文给出了一种变换数据处理方式的改进不确定性重要度分析方法。该模型是以两个累积分布函数之间的空间几何距离为基础,通过改变随机输入变量的不确定性范围和对应分布情况,模拟和描述输入对系统输出变量的相对影响趋势,并以两个累积分布函数之间的定积分面积表示。最后利用系统故障树对其进行不确定性重要度分析。结果表明,空间几何距离是一种用来表示输入变化对输出分布变化的相对影响的不确定性重要度度量的有效工具。     

串联系统多参数广义不确定度传递模式与多反馈控制

将多参数广义不确定度的概念引入串联系统参数不确定度的传递问题中,建立了串联系统多参数广义不确定度传递模型,该模型不仅揭示了参数不确定度在传递过程中的变化情况,传递细节表明传递矩阵元素对最后的传递结果有重要影响.文中阐述了传递矩阵的特征以及各个子系统在串联系统中的主次作用.针对串联系统建立了多参数广义不确定度多反馈控制模型,提出了针对单个系统、两个子系统、多个子系统多个层次的反馈控制模型.模型的提出从理论上说明了当对子系统传递矩阵进行修正时,输出参数不确定度的变化及其上界的面积范数,为工程实际提供了一个良好的理论模型支撑.     

基于极大极小方法的一类非线性系统的自适应控制

研究一类具有非线性不确定参数的非线性系统的自适应模型参考跟踪问题.假设系统的非线性项关于不确定参数是凸或凹的.去掉了在先前有关研究中要求参考模型矩阵有小于零的实特征值的条件.既考虑了状态反馈控制方式,也考虑了输出反馈控制方式.在采用输出反馈控制时,假设非线性项满足李普希兹条件,但李普希兹常数未知.基于一种极大极小方法,提出了一种自适应控制器的设计方法.控制器是连续的,能保证闭环系统的所有变量有界,并且渐近精确跟踪参考模型.举例说明了本结论的有用性.     

The construction of a comprehensive model for production strategy evaluation

To acquire reasonable profits and to be competitive in the globalize market, more and more firms today have exploited various kinds of production strategies, such as outsourcing, joint venture, or some kind of strategic alliance. Since every production strategy has its benefits and costs and may bring a firm different opportunities and risks, which kind of production strategy is the most suitable for a firm to carry out is a difficult and complicated decision with a high degree of uncertainty. Therefore, this research proposes a comprehensive production strategy evaluation model that can facilitate such a decision making for a firm. The factors that should be considered for devising a production strategy are listed for the benefits, opportunities, costs and risks (BOCR) merits first, and fuzzy Delphi method is applied next to select the most important factors under each merit. A network with BOCR merits is constructed to incorporate the selected factors, and fuzzy analytic network process is then applied to consider the interdependence and feedback inside the network. The proposed model can effectively aid decision making on which kind of production strategy should be adopted by a firm. A case of a printed circuit board manufacturer is presented for the illustration of the proposed model.     

Tracking control of nonlinear chaotic systems with dynamics uncertainties

This paper deals with the tracking control of nonlinear chaotic systems with dynamics uncertainties. A robust control strategy is developed to control a class of nonlinear chaotic systems with uncertainties. The proposed strategy is an input-output control scheme which comprises an uncertainty estimator and a linearizing-like feedback. The control time is explicitly computed. Computer simulations of the Duffing system are provided to verify the validity of the proposed control scheme.     

Charge depleting range dynamic strategy with power feedback considering fuel-cell degradation

A charge depleting range dynamic strategy considering the fuel-cell degradation is proposed for the plug-in fuel cell hybrid electric vehicles in this paper, to seek the excellent economy performance with various driving ranges. The proposed strategy is developed by means of incorporating an adaptive equivalent factor into equivalent consumption minimization strategy with power feedback control. Firstly, the mathematical modeling of the proposed strategy is formulated to adjust the equivalent factor corresponding to the battery state of charge, which may vary with the forthcoming trip distance to dominate the expected energy consumption. The fuel cell voltage decay rate is applied to the feedback control of the restricted fuel-cell power, which is designed as the degradation model of fuel cell and integrated with the strategy. Secondly, the realization process of the charge depleting range dynamic strategy with restricted power feedback control model is a new attempt to design the real-time control method. Finally, the proposed strategy is validated by a numerical model developed by using the MATLAB/Simulink software and its effectiveness was evaluated by comparing it with the equivalent consumption minimization strategy. A sensitivity analysis is also conducted to study the effects of different trip distances. The effectiveness of power feedback control in fuel cell durability is validated through a hardware-in-the-loop experiment. The verified results demonstrate the influence of the equivalent factor on the control process, which makes the proposed strategy possible to provide significant improvement in the economy performance and fuel-cell durability.     

Adaptive output feedback asymptotic stabilization of nonholonomic systems with uncertainties

A global adaptive output feedback control strategy is presented for a class of nonholonomic systems in generalized chained form with drift nonlinearity and unknown virtual control parameters. The purpose is to design a nonlinear output feedback switching controller such that the closed-loop system is globally asymptotically stable. By using the input-state scaling technique and an integrator back-stepping approach, an output feedback controller is given. A filter of observer gain is introduced for state and parameter estimates. Meanwhile, in order to avoid the over-parameters, a tuning function technique is utilized. A novel switching control strategy based on the output measurement of the first subsystem rather than time is used to overcome the uncontrollability of the x₀-subsystem in the origin. The proposed controller can guarantee that all the system states globally converge to the origin, while other signals maintain bounded. The numerical simulation testifies the effectiveness.     

基于观测器的模糊Delta算子系统的控制器设计

对于非线性模糊系统控制器和观测器的分析和设计,提出一种统一方法。利用Delta域离散T—S模糊模型对非线性系统建模,并基于李雅普诺夫稳定性理论给出模糊状态反馈控制器和观测器的设计策略,将所得结果归结为求解一组线性矩阵不等式。同时结论表明:分离性原理对Delta算子T—S模糊系统仍然成立。所得结果可将现有关于连续和离散T—S模糊系统的相关结论统一于Delta算子框架内。     

Chaos control in lateral oscillations of spinning disks via nonlinear feedback

In this paper the problem of chaos control in single mode lateral oscillations of spinning disks is studied. At first, using the harmonic balance method, one of the periodic orbits of system is evaluated. Then proposing a nonlinear feedback strategy a control law is presented for chaos elimination by tracking the mentioned periodic solution. It is shown that although the system is not input-state feedback linearizable, by defining an output signal and using the input–output linearization method, the objective of complete periodic orbit tracking is achieved. The sufficient condition for this purpose is presented, and the performance of proposed method is examined by numerical simulation.     

一类时滞非完整系统的反馈控制问题的研究

针对一类具有时滞项的非完整系统,研究了其反馈控制器的设计问题.采用状态转换技术和反推方法,设计了不依赖于时滞的反馈控制器.同时为了处理初值为零的情况,提出了一种新颖的基于第一个子系统输出值的切换控制策略,最后通过仿真算例说明了控制器的有效性.