时滞依赖型区间时滞系统非脆弱H_∞控制

针对一类状态和控制输入矩阵均为区间矩阵的不确定时滞系统,其中状态和控制输入同时具有未知但有上界的时间滞后,基于Lyapunov稳定性理论,利用线性矩阵不等式(LMI)方法,讨论了该类时滞系统的时滞依赖型非脆弱H∞状态反馈控制器设计问题.在区间不确定性和控制器执行机构扰动均满足增益有界条件下,得到了该类时滞系统的满足H∞性能的一个充分条件.通过求解一个线性矩阵不等式(LMIs)组,即可获得鲁棒H∞控制器.最后对某型飞机作机动飞行仿真,仿真结果表明该鲁棒控制器设计方法是有效的.     

一类非线性不确定时滞系统的记忆与无记忆复合H∞状态反馈控制

针对一类具有状态非线性不确定性的线性时滞系统，基于Lyapunov稳定性理论，利用线性矩阵不等式（LMI）方法，讨论了该类时滞系统的记忆与无记忆复合H∞状态反馈控制器的设计问题。在非线性不确定性满足增益有界条件下，得到了该类时滞系统的满足鲁棒H∞性能的一个充分条件。通过求解一个线性矩阵不等式-LMI，即可获得鲁棒H∞控制器。     

具有时滞和的离散系统的稳定性分析

为了解决具有时滞和的离散系统的稳定性问题,基于Lyapunov稳定性理论,通过采用新构造的Lyapunov泛函和线性矩阵不等式处理方法,以线性矩阵不等式形式给出了使得系统满足稳定的时滞相关型准则。同时通过数值实例验证了结果的有效性。研究结果表明:所给准则可有效判定具有时滞和的离散系统的稳定性,该成果对具有时滞和的离系统的稳定性和其它控制问题的进一步研究具有一定参考价值。     

基于LMI的非线性模糊脉冲奇异摄动系统的鲁棒模糊控制

通过推广一般T-S模糊模型定义了一类非线性模糊脉冲奇异摄动系统,基于线性矩阵不等式(LMI)方法提出一种鲁棒模糊控制新方案,采用并行分布补偿(PDC)的基本思想设计状态反馈控制器,并利用Lyapunov理论证明闭环系统全局指数稳定.最后基于LMI方法,将鲁棒模糊控制器的设计问题转化为线性矩阵不等式问题(LMIP).仿真结果表明了该方法的有效性.     

具有时延和丢包的不确定性NCS的稳定性

研究了同时具有网络时延和数据丢包的不确定网络化控制系统的稳定性.将数据丢失看成一种特殊的时延,利用动态反馈控制器设计提高系统的动态性能,得到了总时滞(包括传感器与控制器之间的时滞,控制器与执行器之间的时滞)的表达式,建立了不确定网络化控制系统模型.通过构造李亚普诺夫函数,采用线性矩阵不等式技巧,给出了系统稳定的判定定理.仿真结果表明了该方法的有效性.     

不确定奇异系统的模糊保成本控制

基于T-S模糊模型,研究一类具有状态和输入滞后的不确定奇异系统的模糊保成本控制问题.基于线性矩阵不等式(LMI)的可解性,给出了状态反馈保成本控制器存在的充分条件,该条件保证闭环系统是二次型稳定的,还能获得闭环成本值的上界,所有结果均以线性矩阵不等式的形式给出.数值仿真结果表明该方法是有效的.     

其它自动控制系统

0226716应用于接触网/受电弓混合模拟试验台的计算机测控系统[刊]/吴学杰//计算机工程与应用.—2002,38(12).—213～216(L)0226717关联时滞大系统的分散镇定:线性矩阵不等式方法[刊]/胥布工//控制理论与应用.—2002.19(3).—475～478(E)针对具有未知常时滞的关联大系统,在一定关联分解情况下,建立了可由线性矩阵不等式表示的分散镇定条件。文中给出了一个例子用来说明所提出的线性矩阵不等式方法并比较文献中已有结果。参8     

一类神经网络指数鲁棒稳定性分析

文中研究了一类变时滞区间神经网络的全局指数鲁棒稳定性。取消了变时滞参数为可导函数的假设,通过构造合适的Lyapunov函数,利用Halanay不等式和矩阵范数不等式,得到了一个新颖的区间神经网络全局指数鲁棒稳定的充分条件,该条件与系统的时滞参数无关。根据所得结论,还得到了一个线性矩阵不等式条件,该条件可以用LMI工具箱验证,便于在实际中的应用。最后通过一个数值例子和相应的计算机仿真结果验证了所得结果的有效性。     

具有变时滞的静态神经网络新的稳定性条件

考虑一类具有变时滞的静态神经网络的渐近稳定性问题,基于Lyapunov稳定性理论,时滞分解的思想,并利用时滞导数的上下界,得到了线性矩阵不等式表示的新的渐近稳定性条件,最后,两个数值例子表明所得结果较一些现存结果具有更小的保守性。     

一类时变时滞模糊细胞神经网络的 时滞依赖指数稳定性判据

 针对一类带有时变时滞的模糊细胞神经网络,通过适当的构造Lyapunov-Krasovskii泛函,以线性矩阵不等式的形式提出了一种新颖的依赖于时滞的全局指数稳定性判据.与之前结果相比,所提出的判据针对模糊时滞项进行了变换,从而首次考虑了模糊细胞神经网络中非模糊项的连接权矩阵中元素的符号问题,降低了判据的保守性.并且时滞变化率的限制将被放松.仿真结果进一步证明了判据的有效性.     

新型Liu混沌系统的模糊反馈同步方法

论文研究了新近提出的Liu混沌系统(2004)的模糊反馈同步方法。Liu混沌系统结构不同于以往的连续混沌系统,本文基于T-S(Takagi-Sugeno)模糊模型重构了Liu混沌系统;然后用Lyapunov理论和反馈同步的思想推导了两个重构的Liu系统同步的稳定性条件,并给出了误差系统以衰减率全局渐近稳定的充分条件;最后基于LMI方法进行了仿真实验。良好的仿真结果验证了本文算法的有效性和快速性。     

A NEW UNSUPERVISED CLASSIFICATION ALGORITHM FOR POLARIMETRIC SAR IMAGES BASED ON FUZZY SET THEORY

In this letter, a new method is proposed for unsupervised classification of terrain types and man-made objects using POLarimetric Synthetic Aperture Radar （POLSAR） data. This technique is a combination of the usage of polarimetric information of SAR images and the unsupervised classification method based on fuzzy set theory. Image quantization and image enhancement are used to preprocess the POLSAR data. Then the polarimetric information and Fuzzy C-Means （FCM） clustering algorithm are used to classify the preprocessed images. The advantages of this algorithm are the automated classification, its high classification accuracy, fast convergence and high stability. The effectiveness of this algorithm is demonstrated by experiments using SIR-C/X-SAR （Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar） data.     

基于LMI方法的时滞BAM神经网络的全局稳定性分析

对于时滞双向联想记忆(DBAM)神经网络的平衡点的稳定性问题,目前人们已经得到了很多富有意义的成果。该文提出一种新的神经网络模型标准神经网络模型(SNNM),通过状态的线性变换,将DBAM神经网络转化为时滞SNNM(DSNNM),并利用有关DSNNM的稳定性的一些结论,得到DBAM神经网络平衡点的全局渐近稳定性的充分条件。这些条件都以线性矩阵不等式(LMI)的形式给出,容易验证,保守性低。该方法扩展了以前的稳定性结果,同时也适用于其它类型的递归神经网络(时滞或非时滞)的稳定性分析。     

High Speed Aircraft Robust Fuzzy Controller Design Based on H∞ Performance

The dynamics of the high-speed vehicle (HSV) is partially or completely unknown because of various reasons, such as modeling errors, in-flight failure, and external disturbances. In this paper, a global stability robust fuzzy controller is designed to control the flight F-16 with uncertain perturbation. For the desired H output-feedback controllers, a necessary and sufficient condition of quadratic stability is derived with the well-established results of the Lyapunov stability theory and nonnegative matrix. The controllers not only guarantee the global asymptotically stability of the resultant closed-loop system with external disturbance and parameter perturbation, but also have a desired H performance in a large flight envelop (LFE).     

Dynamic control of electronic differential in the field weakening region

A simple and dynamic electronic differential control method for an outer rotor motor driven electric vehicle based on fuzzy gain scheduling of PI gains method is proposed for constant torque and power region operation using brushless direct current (BLDC) machine. The proposed method is quite insensitive to torque fluctuations and transient speed oscillations due to surface mounted permanent magnet (SMPM) BLDC machines constraints in the field weakening region. To improve the dynamics and stability of the electronic differential system and eliminate the skidding of the wheels and reduce the heating of electric machine in the wide speed range operation, a robust control method is developed. Moreover, PI controller gains are updated continuously by fuzzy gain scheduling approach which has phase advance angle, steering angle and measured speed as controller input parameters in order to eliminate the errors caused from the variable road conditions and torque oscillations in the field weakening region. The proposed method is implemented with 2 × 1.5 kW BLDC motor drive controlled by a TMS320F28335 digital signal processor (DSP). The experimental results show that the proposed method exhibits greater stability under various load, road and vehicle speed conditions.     

移动Ad hoc网络中基于自适应策略的稳定链路选择算法

该文提出了一种基于自适应策略的稳定链路选择算法,定义了稳定邻居度量和本地运动度量两种稳定测度。在此基础上,通过引入模糊隶属度函数得出稳定测度的重要性权值,利用重要性加权的方法即可根据网络状况自适应地得到链路的稳定概率,从而为选择最稳定链路及路由提供依据。仿真结果表明该算法能很好地适应当前的网络状况,明显优于基于LF因子和基于剩余生命时间的链路选择算法,稳定性能显著提高。     

一种模糊滑动模态控制系统稳定性分析研究

分析了模糊滑模控制系统的稳定性，对在具体的应用中所需要注意的问题进行了分析，本文所提供的方法在设计稳定的模糊滑模控制工程中具有一定的实用价值。     

Fuzzy error governor: A practical approach to counter actuator saturation on flexible joint robots

In this paper, a practical method to counter actuator saturation based on a fuzzy error governor is developed and a complete case study is considered. In addition to good performance, the method has two attracting properties: It does not change the structure of the main controller, and therefore, the theoretically proven characteristics of the system are untouched, and it is simply implementable in practice. The proposed controller structure is applied on a flexible joint robot (FJR). The robust stability of the closed loop system for an n-DOF FJR is thoroughly analyzed and the proposed controller is implemented on a laboratory setup to show the ease of implementation and the resulting closed-loop performance. The main controller used for the n-DOF FJR consists of a composite structure, with a PD controller on the fast dynamics and a PID controller on the slow dynamics. The bandwidth of the fast controller is decreased during critical occasions with the fuzzy logic supervisor, which adjusts the loop gain to a proper level. Using Lyapunov direct method, the robust stability of the overall system is analyzed in presence of modeling uncertainties, and it is shown that if the PD and the PID gains are tuned to satisfy certain conditions, the closed loop system becomes UUB stable.     

遗传算法中突变算子的数学分析及改进策略

本文在简要介绍遗传算法的基础上,通过引入#em/em#位改进子空间的概念,对不同情形下突变概率的最优选取进行了分析,然后采用模糊推理技术来确定选取突变概率的一般性原则。良好的仿真结果显示了本文所提改进策略的有效性。     

Comparison between braking and steering yaw moment controllers considering ABS control aspects

Two yaw motion control systems that improve a vehicle lateral stability are proposed in this study: a braking yaw motion controller (BYMC) and a steering yaw motion controller (SYMC). A BYMC controls the braking pressure of the rear inner wheel, while a SYMC steers the rear wheels to allow the yaw rate to track the reference yaw rate. A 15 degree-of-freedom vehicle model, simplified steering system model, and driver model are used to evaluate the proposed BYMC and SYMC. A robust anti-lock braking system (ABS) controller is also designed and developed. The performance of the BYMC and SYMC are evaluated under various road conditions and driving inputs. They reduce the slip angle when braking and steering inputs are applied simultaneously, thereby increasing the controllability and stability of the vehicle on slippery roads. The SYMC performs better than the BYMC because the SYMC vehicle has four-wheel steering. However, both the BYMC and SYMC vehicles show improved performance during lane-change maneuvers.