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基于时域弹跳射线与BP算法的聚束SAR目标电磁成像快速仿真方法 被引量:1
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作者 杨鹏举 张蓉 +1 位作者 吴瑞 田炜 《电波科学学报》 北大核心 2025年第1期80-88,共9页
针对复杂群目标合成孔径雷达(synthetic aperture radar,SAR)电磁成像快速模拟问题,采用一种基于宽度优先搜索(breadth-first search,BFS)算法进行K-d树构建,显著提升了时域弹跳射线(time-domain shooting and bouncing ray,TDSBR)法的... 针对复杂群目标合成孔径雷达(synthetic aperture radar,SAR)电磁成像快速模拟问题,采用一种基于宽度优先搜索(breadth-first search,BFS)算法进行K-d树构建,显著提升了时域弹跳射线(time-domain shooting and bouncing ray,TDSBR)法的射线追踪效率。使用TDSBR法分析了复杂电大尺寸目标的时域电磁响应特性,结合后向投影(back-projection,BP)算法对雷达回波信号进行聚焦处理进而获得了复杂目标的高分辨SAR图像。通过与FEKO软件中的频域射线追踪算法进行对比,验证了本文TDSBR算法在复杂群目标SAR电磁成像快速模拟中的有效性和高效性。 展开更多
关键词 电磁散射 K-D树 时域弹跳射线(TDSBR)法 后向投影(bp)算法 聚束合成孔径雷达(SAR)成像
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基于BP-Adaboost.M2的布里渊光时域分析传感系统温度提取技术研究
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作者 郑欢 韩曼 +1 位作者 舒涵 徐诺 《传感技术学报》 北大核心 2025年第5期809-816,共8页
提出了使用BP-Adaboost.M2从布里渊光时域分析(Brillouin Optical Time Domain Analysis,BOTDA)传感器的布里渊增益谱(Brillouin Gain Spectrum,BGS)中提取温度信息的新方法。该方法将温度提取视为有监督的单标签多分类问题,利用带高斯... 提出了使用BP-Adaboost.M2从布里渊光时域分析(Brillouin Optical Time Domain Analysis,BOTDA)传感器的布里渊增益谱(Brillouin Gain Spectrum,BGS)中提取温度信息的新方法。该方法将温度提取视为有监督的单标签多分类问题,利用带高斯白噪声的BGS数据构建训练特征集,其对应的温度属性构成训练标签集。采用反向传播神经网络(Back Propagation Neural Network,BPNN)作为弱多分类器,经过训练后,利用Adaboost.M2集成算法将多个BPNN组成一个强多分类器。根据训练后得到的BP-Adaboost.M2模型,可以将新的测量BGS分类到每个温度类别中,实现对温度传感信息的提取。通过仿真和实验研究了信噪比和扫频步长对温度提取性能的影响,并与洛伦兹曲线拟合(Lorentzian Curve Fitting,LCF)、伪Voigt曲线拟合(pseudo-Voigt Curve Fitting,pVCF)和BPNN技术进行了比较。实验结果表明,在信噪比低于11 dB以及不同的扫频步长的情况下,BP-Adaboost.M2方法提取的温度均方根误差和不确定度最小。BP-Adaboost.M2对1000个数据样本的处理时间仅为1.91 s,比BPNN方法约快1.25倍;比LCF和pVCF方法快100倍以上。 展开更多
关键词 布里渊光时域分析 布里渊增益谱 bp-Adaboost.M2 单标签多分类
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基于改进SSA-BP神经网络的弹丸全弹道飞行时间预测
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作者 郝博 徐才宪 +1 位作者 姜琦 杨斌 《火力与指挥控制》 北大核心 2025年第3期130-134,141,共6页
采用改进的麻雀搜索算法对BP神经网络的权值与阈值进行全局最优,在麻雀搜索算法中引入Tent混沌映射策略来初始化种群,同时引入高斯变异和高斯扰动策略以及自适应惯性权重策略,提高SSA算法跳出局部最优的能力和求解精度,以提高在弹道系... 采用改进的麻雀搜索算法对BP神经网络的权值与阈值进行全局最优,在麻雀搜索算法中引入Tent混沌映射策略来初始化种群,同时引入高斯变异和高斯扰动策略以及自适应惯性权重策略,提高SSA算法跳出局部最优的能力和求解精度,以提高在弹道系数、发射角度、风速和弹丸初速已知的条件下对弹丸全弹道飞行时间预测的准确性与稳定性。结果表明,改进SSA-BP预测模型提高了弹丸全弹道飞行时间预测的稳定性与准确性。 展开更多
关键词 弹丸全弹道飞行时间 bp神经网络 SSA优化算法 Tent混沌映射 高斯变异
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Uniformed model of networked control systems with long time delay 被引量:4
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作者 Zhu Qixin Liu Hongli Hu Shousong 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第2期385-390,共6页
Feedback control systems wherein the control loops are closed through a real-time network are called networked control systems (NCS). The defining feature of an NCS is that information is exchanged using a network a... Feedback control systems wherein the control loops are closed through a real-time network are called networked control systems (NCS). The defining feature of an NCS is that information is exchanged using a network among control system components. Two new concepts including long time delay and short time delay are proposed. The sensor is almost always clock driven. The controller or the actuator is either clock driven or event driven. Four possible driving modes of networked control systems are presented. The open loop mathematic models of networked control systems with long time delay are developed when the system is driven by anyone of the four different modes. The uniformed modeling method of networked control systems with long time delay is proposed. The simulation results are given in the end. 展开更多
关键词 networked control systems time delay MODEL driving mode.
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Iterative identification of discrete-time output-error model with time delay 被引量:3
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作者 CHEN Feng-wei LIU Tao 《Journal of Central South University》 SCIE EI CAS CSCD 2017年第3期647-654,共8页
The problem of discrete-time model identification of industrial processes with time delay was investigated.An iterative and separable method is proposed to solve this problem,that is,the rational transfer function mod... The problem of discrete-time model identification of industrial processes with time delay was investigated.An iterative and separable method is proposed to solve this problem,that is,the rational transfer function model parameters and time delay are alternately fixed to estimate each other.The instrumental variable technique is applied to guarantee consistent estimation against measurement noise.A noteworthy merit of the proposed method is that it can handle fractional time delay estimation,compared to existing methods commonly assuming that the time delay is an integer multiple of the sampling interval.The identifiability analysis for time delay is addressed and correspondingly,some guidelines are provided for practical implementation of the proposed method.Numerical and experimental examples are presented to illustrate the effectiveness of the proposed method. 展开更多
关键词 system identification output-error model instrumental variable method time delay
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Narrowband time delay estimation based on correlation coefficient 被引量:3
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作者 Gao Yang Qiu Tianshuang Sha Lan Zhao Yanbin 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2009年第5期937-941,共5页
The problems of time delay estimation of narrowband signals are presented. The disadvantages of the existing algorithms are analyzed, and a new narrowband time delay estimating algorithm based on correlation coefficie... The problems of time delay estimation of narrowband signals are presented. The disadvantages of the existing algorithms are analyzed, and a new narrowband time delay estimating algorithm based on correlation coefficient is proposed. The original time delay information is transfered into the delay between the autocorrelation and cross-correlation function, and the precise estimating result by wave-comparison is given. The algorithm proposed here is also compared with other algorithms and its advantages over other algorithms are proved. The theoretical analysis and simulation show the effectiveness of the proposed algorithm. 展开更多
关键词 time delay estimation narrowband signal correlation coefficient.
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Cascade control based on minimum sensitivity in outer loop for processes with time delay 被引量:6
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作者 尹成强 惠鸿忠 +2 位作者 岳继光 高洁 郑丽萍 《Journal of Central South University》 SCIE EI CAS 2012年第9期2689-2696,共8页
A new cascade control program was proposed based on modified internal model control to handle stable,unstable and integrating processes with time delay.The program had totally four controllers of which the secondary l... A new cascade control program was proposed based on modified internal model control to handle stable,unstable and integrating processes with time delay.The program had totally four controllers of which the secondary loop had two controllers and the primary loop had two controllers.The two secondary loop controllers were designed using IMC technique.They were decoupled completely and could be adjusted independently,which avoided the undesirable influence on performance of the primary controllers.The main controller in the primary loop was devised as a PID using the method of minimum sensitivity,which could guarantee not only the nominal performance but also the robust stability of the system.A setpoint filter was added in the primary loop to improve the tracking performance.All the controllers of the two closed-loops were designed analytically,and could be adjusted and optimized by single parameter respectively.Simulations were carried out on three various processes with time delay,and the results show that the proposed method can provide a better performance of both set-point tracking and disturbance rejection and robustness against parameters perturbation. 展开更多
关键词 cascade control time delay H∞ performance specification modified internal mode control multiple degrees of freedom
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Underdetermined DOA estimation via multiple time-delay covariance matrices and deep residual network 被引量:4
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作者 CHEN Ying WANG Xiang HUANG Zhitao 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2021年第6期1354-1363,共10页
Higher-order statistics based approaches and signal sparseness based approaches have emerged in recent decades to resolve the underdetermined direction-of-arrival(DOA)estimation problem.These model-based methods face ... Higher-order statistics based approaches and signal sparseness based approaches have emerged in recent decades to resolve the underdetermined direction-of-arrival(DOA)estimation problem.These model-based methods face great challenges in practical applications due to high computational complexity and dependence on ideal assumptions.This paper presents an effective DOA estimation approach based on a deep residual network(DRN)for the underdetermined case.We first extract an input feature from a new matrix calculated by stacking several covariance matrices corresponding to different time delays.We then provide the input feature to the trained DRN to construct the super resolution spectrum.The DRN learns the mapping relationship between the input feature and the spatial spectrum by training.The proposed approach is superior to existing model-based estimation methods in terms of calculation efficiency,independence of source sparseness and adaptive capacity to non-ideal conditions(e.g.,low signal to noise ratio,short bit sequence).Simulations demonstrate the validity and strong performance of the proposed algorithm on both overdetermined and underdetermined cases. 展开更多
关键词 direction-of-arrival(DOA)estimation underdetermined condition deep residual network(DRN) time delay covariance matrix
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Time delay control of hydraulic manipulators with continuous nonsingular terminal sliding mode 被引量:2
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作者 王尧尧 陈家旺 +1 位作者 顾临怡 李晓东 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第12期4616-4624,共9页
For the position tracking control of hydraulic manipulators,a novel method of time delay control(TDC) with continuous nonsingular terminal sliding mode(CNTSM) was proposed in this work.Complex dynamics of the hydrauli... For the position tracking control of hydraulic manipulators,a novel method of time delay control(TDC) with continuous nonsingular terminal sliding mode(CNTSM) was proposed in this work.Complex dynamics of the hydraulic manipulator is approximately canceled by time delay estimation(TDE),which means the proposed method is model-free and no prior knowledge of the dynamics is required.Moreover,the CNTSM term with a fast-TSM-type reaching law ensures fast convergence and high-precision tracking control performance under heavy lumped uncertainties.Despite its considerable robustness against lumped uncertainties,the proposed control scheme is continuous and chattering-free and no pressure sensors are required in practical applications.Theoretical analysis and experimental results show that faster and higher-precision position tracking performance is achieved compared with the traditional CNTSM-based TDC method using boundary layers. 展开更多
关键词 time delay control terminal sliding mode MODEL-FREE hydraulic manipulators
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New HB-weighted time delay estimation algorithm under impulsive noise environment 被引量:2
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作者 Sun Yongmei Qiu Tianshuang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2008年第6期1102-1108,共7页
The traditional HB-weighted time-delay estimation (TDE) method degenerates under the impulsive noise environment. Two new time-delay estimation methods are proposed based on fractional lower order statistics (FLOS... The traditional HB-weighted time-delay estimation (TDE) method degenerates under the impulsive noise environment. Two new time-delay estimation methods are proposed based on fractional lower order statistics (FLOS) according to the impulsive characteristics of fractional lower order α-stable noises. Theoretic analysis and computer simulations indicate that the proposed covariation based HB weighted (COV-HB) algorithm can suppress impulsive noises in one received signal for 1 ≤α≤ 2, whereas the other proposed fractional lower order eovariancebased HB weighted (FLOC-HB) algorithm has robust performance under arbitrary impulsive noise conditions for the whole range of 0 〈α≤ 2. 展开更多
关键词 HB weighted time delay COVARIATION fractional lower order covariance.
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Dynamics of the HBV model with diffusion and time delay 被引量:2
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作者 QIAO mei-hong,QI huan(Department of Control Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074) 《医用生物力学》 EI CAS CSCD 2009年第S1期117-118,共2页
Chronic hepatitis B infection is a major health problem,with approximately 350 million virus carriers worldwide.In Africa,about 30%-60% of children and 60%-100% of adults have
关键词 HBV time Dynamics of the HBV model with diffusion and time delay
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Fault detection and optimization for networked control systems with uncertain time-varying delay 被引量:2
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作者 Qing Wang Zhaolei Wang +1 位作者 Chaoyang Dong Erzhuo Niu 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2015年第3期544-556,共13页
The observer-based robust fault detection filter design and optimization for networked control systems (NOSs) with uncer- tain time-varying delays are addressed. The NCSs with uncertain time-varying delays are model... The observer-based robust fault detection filter design and optimization for networked control systems (NOSs) with uncer- tain time-varying delays are addressed. The NCSs with uncertain time-varying delays are modeled as parameter-uncertain systems by the matrix theory. Based on the model, an observer-based residual generator is constructed and the sufficient condition for the existence of the desired fault detection filter is derived in terms of the linear matrix inequality. Furthermore, a time domain opti- mization approach is proposed to improve the performance of the fault detection system. To prevent the false alarms, a new thresh- old function is established, and the solution of the optimization problem is given by using the singular value decomposition (SVD) of the matrix. A numerical example is provided to illustrate the effectiveness of the proposed approach. 展开更多
关键词 fault detection networked control systems residual generator time-varying delay time domain optimization approach.
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Adaptive sliding mode control of modular self-reconfigurable spacecraft with time-delay estimation 被引量:1
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作者 Xin-hong Li Zhi-bin Zhang +4 位作者 Ji-ping An Xin Zhou Gang-xuan Hu Guo-hui Zhang Wan-xin Man 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2022年第12期2170-2180,共11页
The reconstruction control of modular self-reconfigurable spacecraft (MSRS) is addressed using an adaptive sliding mode control (ASMC) scheme based on time-delay estimation (TDE) technology. In contrast to the ground,... The reconstruction control of modular self-reconfigurable spacecraft (MSRS) is addressed using an adaptive sliding mode control (ASMC) scheme based on time-delay estimation (TDE) technology. In contrast to the ground, the base of the MSRS is floating when assembled in orbit, resulting in a strong dynamic coupling effect. A TED-based ASMC technique with exponential reaching law is designed to achieve high-precision coordinated control between the spacecraft base and the robotic arm. TDE technology is used by the controller to compensate for coupling terms and uncertainties, while ASMC can augment and improve TDE’s robustness. To suppress TDE errors and eliminate chattering, a new adaptive law is created to modify gain parameters online, ensuring quick dynamic response and high tracking accuracy. The Lyapunov approach shows that the tracking errors are uniformly ultimately bounded (UUB). Finally, the on-orbit assembly process of MSRS is simulated to validate the efficacy of the proposed control scheme. The simulation results show that the proposed control method can accurately complete the target module’s on-orbit assembly, with minimal perturbations to the spacecraft’s attitude. Meanwhile, it has a high level of robustness and can effectively eliminate chattering. 展开更多
关键词 Adaptive sliding mode control(ASMC) time delay control time delay estimation Modular self-reconfigurable spacecraft Uncertainty Coordinated control
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Design of decoupling Smith control for multivariable system with time delays 被引量:1
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作者 黄灿 桂卫华 +1 位作者 阳春华 谢永芳 《Journal of Central South University》 SCIE EI CAS 2011年第2期473-478,共6页
In order to solve the decoupling control problem of multivariable system with time delays,a new decoupling Smith control method for multivariable system with time delays was proposed. Firstly,the decoupler based on th... In order to solve the decoupling control problem of multivariable system with time delays,a new decoupling Smith control method for multivariable system with time delays was proposed. Firstly,the decoupler based on the adjoint matrix of the multivariable system model with time delays was introduced,and the decoupled models were reduced to first-order plus time delay models by analyzing the amplitude-frequency and phase-frequency characteristics. Secondly,according to the closed-loop characteristic equation of Smith predictor structure,proportion integration (PI) controllers were designed following the principle of pole assignment for Butterworth filter. Finally,using small-gain theorem and Nyquist stability criterion,sufficient and necessary conditions for robust stability were analyzed with multiplicative uncertainties,which could be encountered frequently in practice. The result shows that the method proposed has superiority for response speed and load disturbance rejection performance. 展开更多
关键词 multivariable process time delay Smith predictor DECOUPLING robust stability
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Decentralized Robust Control for Large Scale Interconnected Uncertain Systems with Time delay 被引量:1
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作者 TANG Zhao hui,WU Min,GUI Wei hua,XIE Yong fang (College of Information Engineering, Central South University of Technology, Changsha 410083, China) 《Journal of Central South University》 SCIE EI CAS 2000年第1期49-52,共4页
For a class of interconnected time delay uncertain systems satisfing the matching conditions, the sufficient condition for decentralized stabilization feedback control laws is derived based on Lyapunov stability theor... For a class of interconnected time delay uncertain systems satisfing the matching conditions, the sufficient condition for decentralized stabilization feedback control laws is derived based on Lyapunov stability theorem. This condition is expressed as the solvability problem of linear matrix inequalities(LMI). It can be easily determined whether or not, it is feasible and one can easily obtain the decentralized stabilizing state feedback matrices via LMI techniques. The method overcomes the limitations of the existing algebraic Riccati equation method. The given example shows the application of the method. 展开更多
关键词 UNCERTAINTIES time delay linear matrix inequality decentralized control ROBUSTNESS
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Joint DOA and time delay estimation method for space-time coherent distributed signals based on search 被引量:1
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作者 Qian Bin Yang Wanlin Wan Qun 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2007年第2期341-346,共6页
Under dense urban fading environment, performance of joint multi-path parameter estimation method based on traditional point signal model degrades seriously. In this paper, a new space and time signal model based on m... Under dense urban fading environment, performance of joint multi-path parameter estimation method based on traditional point signal model degrades seriously. In this paper, a new space and time signal model based on multipath distribution function is given after new space and time manifold is reconstructed. Then joint spacetime signal subspace is obtained by converting acquired channel from time domain to frequency domain .Then space and time spectrum is formulated by the space sub-matrix and time sub-matrix taken out of joint space-time signal subspace, and parameters are estimated by searching the minimum eigenvalues of the space matrix and the time matrix. Lastly, A space and time parameters matching process is performed by using the orthogonal property between joint noise subspace and the space-time manifold. In contrast with tradition MUSIC, the algorithm we present here only need two 1- dimension searching and was not sensitive to different distribution function. 展开更多
关键词 Space-time coherent distribution DOA Relative time delay Minimum eigenvalue.
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Robust H∞ Control with Exponent Stability for Time-Delay Uncertain Systems 被引量:1
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作者 Luo Xiaoyuan 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2002年第1期27-33,共7页
This paper is concerned with the robust H ∞ control with exponent stability for a class of time delay uncertain systems. Attention is focused on the design of controllers such that the resulting closed loop system... This paper is concerned with the robust H ∞ control with exponent stability for a class of time delay uncertain systems. Attention is focused on the design of controllers such that the resulting closed loop system not only is exponentially stable but also satisfies, H ∞ disturbance attenuance via memoryless state feedback control. Sufficient conditions for feasibility are obtained in terms of LMIs. Moreover, optimization of LMI is considered such that the controller with low gain parameters is formulated. 展开更多
关键词 Uncertain system time delay Robust H control Exponent attenuance LMI.
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Actuator fault diagnosis of time-delay systems based on adaptive observer 被引量:1
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作者 尤富强 田作华 施颂椒 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第3期624-631,共8页
A novel approach for the actuator fault diagnosis of time-delay systems is presented by using an adaptive observer technique. Systems without model uncertainty are initially considered, followed by a discussion of a g... A novel approach for the actuator fault diagnosis of time-delay systems is presented by using an adaptive observer technique. Systems without model uncertainty are initially considered, followed by a discussion of a general situation where the system is subjected to either model uncertainty or external disturbance. An adaptive diagnostic algorithm is developed to diagnose the fault, and a modified version is proposed for general system to improve robustness. The selection of the threshold for fault detection is also discussed. Finally, a numerical example is given to illustrate the efficiency of the proposed method. 展开更多
关键词 fault detection and diagnosis adaptive observer linear systems time delay.
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Novel l_2-l_∞ controller design for LPV discrete time-delay systems 被引量:1
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作者 WangJunling WangChanghong LiYanhui GaoHuijun 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第1期128-133,共6页
One of the first attempts to derive energy-to-peak performance criteria and state-feedback controller design problem for linear parameter-varying discrete time systems with time delay is provided. Firstly, we present ... One of the first attempts to derive energy-to-peak performance criteria and state-feedback controller design problem for linear parameter-varying discrete time systems with time delay is provided. Firstly, we present a parameter-dependent l 2-l ∞ performance criterion using a parameter-dependent Lyapunov function. Upon the conditions addressed, an improved parameter-dependent l 2-l ∞ performance criterion is established by the introduction of a slack variable, which exhibits a kind of decoupling between Lyapunov functions and system matrices. This kind of decoupling enables us to obtain more easily tractable conditions for analysis and synthesis problems. Then, the corresponding parameter-dependent state-feedback controller design is investigated upon these performance criteria, with sufficient conditions obtained for the existence of admissible controllers in terms of parameterized linear matrix inequalities. Finally, a numerical example is provided to illustrate the feasibility and advantage of the proposed controller design procedure. 展开更多
关键词 linear parameter-varying discrete-time system parameterized linear matrix inequality time delay l 2-l control.
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H_-/H_∞ fault detection filter design for interval time-varying delays switched systems 被引量:3
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作者 Jiawei Wang Yi Shen Zhenhua Wang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2016年第4期878-886,共9页
The problem of the robust fault detection filter design for time-varying delays switched systems is considered in the framework of mixed H-/H∞. Firstly, the weighted H∞ performance index is utilized as the robustnes... The problem of the robust fault detection filter design for time-varying delays switched systems is considered in the framework of mixed H-/H∞. Firstly, the weighted H∞ performance index is utilized as the robustness performance, and the H- index is used as the sensitivity performance for obtaining the robust fault detection filter. Then a novel multiple Lyapunov-Krasovskii function is proposed for deriving sufficient existence conditions of the robust fault detection filter based on the average dwell time technique. By introducing slack matrix variable, the coupling between the Lyapunov matrix and system matrix is removed, and the conservatism of results is reduced. Based on the robust fault detection filter, residual is generated and evaluated for detecting faults. In addition, the results of this paper are dependent on time delays,and represented in the form of linear matrix inequalities. Finally,the simulation example verifies the effectiveness of the proposed method. 展开更多
关键词 switched system average dwell time mixed H-/H∞ robust fault detection filter time-varying delay
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