空时MIMO-OFDM 系统中基于扩展Kalman 滤波的信道估计

A space-time coded multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) system is considered as a solution to the future wideband wireless communication system.This paper proposes an extended Kalman filtering-based (EKF-based) channel estimation method for space-time coded MIMO-OFDM systems.The proposed method can exploit pilot symbols and an extended Kalman filter to estimate channel without any prior knowledge of channel statistics.In comparison with the least square (LS) and the least mean square (LMS) methods,the EKF-based approach has a better performance in theory.Computer simulations demonstrate the proposed method outperforms the LS and LMS methods.Therefore it can offer dramatic system performance improvement at a modest cost of computational complexity.     

鲁棒融合Kalman滤波在异步电机转速控制中的应用

协方差交叉融合算法是新兴的一种分布式融合算法,该算法避免了局部互协方差或相关阵的计算,算法简单,故得到了广泛的应用.以异步电机转速控制为应用背景,进行协方差交叉融合Kalman滤波算法的应用研究.相比已有的单传感器状态估计,所提出的协方差交叉融合状态估计算法估计精度更高.仿真实例分析说明了所提出的算法的有效性.     

一类非线性扰动不确定时滞系统的鲁棒镇定

主要讨论了一类非线性扰动不确定时滞系统的鲁棒镇定问题。先讨论无扰动的自由系统和有扰动的系统的稳定性问题,接着通过构造无记忆状态反馈控制器,给出了使闭环系统具有一定的鲁棒性的充分条件.     

一类非线性扰动中立型系统的鲁棒镇定

讨论了一类非线性扰动中立型系统的鲁棒镇定问题．在非线性不确定性满足增益有界条件下，首先给出了自由系统鲁棒稳定的一个充分条件，接着通过构造无记忆状态反馈控制器，给出了闭环系统渐近稳定的充分条件．     

基于CI算法的多传感器时滞航迹的分布式融合估计

网络的传感器节点向处理中心传输局部估计时,不可避免地存在随机延迟,从而导致航迹无序现象频发。在分布式框架下,研究多传感器时滞航迹的融合估计问题。采用最新可利用的局部估计原则,若未收到最新局部估计,则用之前收到的最新的估计进行预报。进而,运用避免计算互协方差阵的CI算法进行分布式融合。避免了计算互协方差阵,且能改善局部估计的精度。仿真例子说明算法的有效性。     

研析带有非线性时滞系统的鲁棒稳定性

文中针对一类同时具有非线性摄动和强结构不确定参数的时滞系统,利用线性矩阵不等式方法,研究其鲁棒稳定性问题．给出了有记忆状态反馈鲁棒稳定控制律存在的充分条件和具体设计方法,最后用Matalb软件进行实例仿真演示了该方法的有效性．     

非线性时变时滞系统的鲁棒H_∞控制

针对一类受扰非线性时变时滞系统,构造一个Lyapunov-Krasovskii泛函,利用积分不等式及线性矩阵不等式技术,给出系统状态反馈鲁棒H∞控制器存在的充分条件及具体设计方法.数值算例验证了该方法的有效性.     

连续凸多面体不确定系统的鲁棒L2-L∞滤波

基于新的鲁棒稳定条件，提出了依赖于参数的凸多面体不确定连续系统的鲁棒L2-L∞性能新判据。利用该判据，采用增广线性矩阵不等式技术推导了此类系统的全阶和降阶的鲁棒L2-L∞滤波斯方法。与已有的方法相比，所提出的算法具有较低的保守性。数值例子说明了设计方法的有效性。     

一类不确定参数线性离散系统的鲁棒特性分析

研究了一类含不确定参数线性离散系统的鲁棒H∞特性,其中系统的不确定参数满足范数有界条件。文章所讨论的系统可以看作是在状态和输入上均有不确定参数的线性离散系统。给定H∞性能指标,采用线性矩阵不等式方法,得到了系统具有鲁棒H∞特性的充分条件,同时利用线性矩阵不等式给出了不确定参数容许范围的计算方法。     

多时滞不确定非线性系统的鲁棒预测控制

对于一类非线性不确定系统,分别考虑时变和多时滞不确定的情况,讨论其鲁棒预测控制设计问题在"最小-最大"的性能指标下,根据时滞选择了相关的Lyapunov函数,并采用了变量变换的思想和LMI方法,近似求解无穷时域的优化问题,将系统考虑分段连续的情况,解决了反复在线优化的可行性问题,保证了闭环系统的鲁棒稳定.最后通过仿真实例,验证了算法的有效性.     

非线性非方广义系统降阶Kalman状态估值器

利用Taylor级数展开法将非线性非方广义系统线性化,再利用奇异值分解方法将线性化后的非方广义系统降阶为等价正常系统;基于Kalman滤波理论,得到非线性非方广义系统Kalman状态预报器和滤波器。并给出了数值Matlab仿真算例,验证了所提方法的有效性。     

Exponential stability for networked control systems based on the model of nonlinear discrete-time system with time-varying delay

1.IntroductionAsthecomplexityofmoderncontrolsystems,itsdimensionbecomesmoreandmorevast.Actuators,sensorsandcontrollersinsystemsareusuallydistributed.Theclose-loopfeedbackcontrolsystemscanbeestablishedviaconnectingthesenodeswithcommunicationnetwork.Thesesystemsareoftencallednetworkedcontrolsystems(NCSs).TheNCSsbasedonfieldbusnetwork,suchasCANbus,havebeenwidelyusedinvariousindustrialareasinrecentyears.Therearemanynewissueswhenusingnewsystems.Thefirstissueisthenetwork-induceddelay(sensor-to-…     

Recursive calibration for a lithium iron phosphate battery for electric vehicles using extended Kalman filtering

In this paper, an efficient model structure composed of a second-order resistance-capacitance network and a simply analytical open circuit voltage versus state of charge (SOC) map is applied to characterize the voltage behavior of a lithium iron phosphate battery for electric vehicles (EVs). As a result, the overpotentials of the battery can be depicted using a second-order circuit network and the model parameterization can be realized under any battery loading profile, without a special characterization experiment. In order to ensure good robustness, extended Kalman filtering is adopted to recursively implement the calibration process. The linearization involved in the calibration algorithm is realized through recurrent derivatives in a recursive form. Validation results show that the recursively calibrated battery model can accurately delineate the battery voltage behavior under two different transient power operating conditions. A comparison with a first-order model indicates that the recursively calibrated second-order model has a comparable accuracy in a major part of the battery SOC range and a better performance when the SOC is relatively low.     

Estimation of vehicle states and tire-road friction using parallel extended Kalman filtering

A model-based estimator design and implementation is described in this paper to undertake combined estimation of vehicle states and tire-road friction coefficients. The estimator is designed based on a vehicle model with three degrees of freedom (3-DOF) and the dual extended Kalman filter (DEKF) technique is employed. Effectiveness of the estimation is examined and validated by comparing the outputs of the estimator with the responses of the vehicle model in CarSim in three typical road adhesion conditions (high-friction, low-friction, and joint-friction roads). Simulation results demonstrate that the DEKF estimator algorithm designed is able to obtain vehicle states (e.g., yaw rate and roll angle) as well as road friction coefficients with reasonable accuracy.     

抑制扩频系统中窄带干扰的新卡尔曼滤波算法

A new Kalman filtering algorithm based on estimation of spread spectrum signal before suppression of narrowband interference （NBI） in spread spectrum systems, using the dependence of autoregressive （AR） interference, is presented compared with performance of the ACM nonlinear filtering algorithm, simulation results show that the proposed algorithm has preferable performance, there is about 5 dB SNR improvement in average.     

非线性不确定系统鲁棒自适应动态面控制

本文针对具有未知参数不确定和干扰的严格反馈型的非线性系统鲁棒自适应控制提出了一种新的设计方法 ,即动态面控制 .传统的递推算法要求对建模的非线性反复多次微分 .本文方法由于加入了n个低通滤波器使得算法不用对模型非线性进行多次微分 ,因而避免了因“微分项的爆炸”引起的算法复杂性从而简化了算法 .理论分析证明了所设计的鲁棒自适应动态面控制器保证了闭环系统的半全局渐近稳定并且使得输出跟踪期望轨迹 .仿真结果表明了所设计的控制器的有效性和可行性 .     

基于扩张状态观测器的鲁棒转子磁链估计研究

提出了新型的基于线性扩张状态观测器的感应电动机转子磁链估计模型。以两个独立的线性扩张状态观测器观测定子电流,用分别被扩张的两个状态构建闭环转子磁链观测器,根据Lyapunov稳定性理论推导满足转子磁链观测器渐进稳定的反馈增益矩阵和转速估计自适应律。利用Matlab进行了仿真,分析了电机参数变化对磁链观测和转速估计精度的影响,表明了提出的模型对电机参数变化具有强鲁棒性。     

一种快衰落信道中OFDM系统的Kalman信道估计方法

针对频率选择性快衰落信道的多径干扰和较大的多普勒频率扩展,提出了一种基于导频的低维Kalman滤波算法用于正交频分复用(OFDM)系统信道估计.为了简化计算,采用一阶自回归(AR)过程对时变信道进行建模.利用复杂度大大降低的一维Kalman滤波算法进行单个子载波的并行信道估计,并采用基于导频的最小平方(LS)算法估计时变的信道衰减因子a.为了同时跟踪信道的频域相关性,采用了最小均方误差(MMSE)线性合并器对Kalman信道估计结果进行修正.在5.5 GHz频段上的仿真表明了这种基于导频的低维Kalman信道估计方法,降低了传统的Kalman滤波结构的复杂度,能够跟踪信道的时频变化,并且在一定程度上可以接近于理想信道估计的误码率性能.