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Robust maximum-likelihood parameter estimation of stochastic state-space systems based on EM algorithm

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Progress in Natural Science:Materials International 2007年第9期17卷 1095-1103页

作者： Zhong Lusheng(National laboratory of industrial control technology,Institute of industrial Process control,zhejiang university,hangzhou 31.02.,china) National laboratory of industrial control technology Institute of Industrial Process Control Zhejiang University Hangzhou 310027 China

This paper addresses the problems of parameter estimation of multivariable stationary stochastic systems on the basis of observed output *** main contribution is to employ the expectation-maximisation(EM)method as a means for computation of the maximum-likelihood(ML)parameter estimation of the *** form of the expectation of the studied system subjected to Gaussian distribution noise is derived and parameter choice that maximizes the expectation is also *** results in an iterative algorithm for parameter estimation and the robust algorithm implementation based on technique of QR-factorization and Cholesky factorization is also ***,algorithmic properties such as non-decreasing likelihood value,necessary and sufficient conditions for the algorithm to arrive at a local stationary parameter,the convergence rate and the factors affecting the convergence rate are *** study shows that the proposed algorithm has attractive properties such as numerical stability,and avoidance of difficult initial conditions.

关键词： parameter estimation system identification maximum likelihood(ML) stochastic state-space system EM algorithm

Map building for dynamic environments using grid vectors

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Journal of zhejiang university-Science C(Computers and Electronics) 2011年第7期12卷 574-588页

作者： Wen-fei WANG,Rong XIONG ,Jian CHU (state key laboratory of industrial control technology,Institute of Cyber-Systems and control,zhejiang university,hangzhou 31.02.,china) state key laboratory of industrial control technology Institute of Cyber-Systems and Control Zhejiang University

This paper addresses the problem of creating a geometric map with a mobile robot in a dynamic indoor *** form an accurate model of the environment,we present a novel map representation called the 'grid vector',which combines each vector that represents a directed line segment with a slender occupancy grid map.A modified expectation maximization (EM) based approach is proposed to evaluate the dynamic objects and simultaneously estimate the robot path and the map of the *** probability of each grid vector is evaluated in the expectation step and then used to distinguish the vector into static and dynamic *** robot path and map are estimated in the maximization step with a graph-based simultaneous localization and mapping (SLAM) *** representation we introduce provides advantages on making the SLAM method strictly statistic,reducing memory cost,identifying the dynamic objects,and improving the accuracy of the data *** SLAM algorithm we present is efficient in computation and *** on three different kinds of data sets show that our representation and algorithm can generate an accurate static map in a dynamic indoor environment.

关键词： Grid vector Line Segments Dynamic Simultaneous localization and mapping (SLAM) Expectation maximization (EM)

Networked Kalman filtering with combined constraints of bandwidth and random delay

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Science china(Information Sciences) 2012年第10期55卷 2343-2357页

作者： GE QuanBo 1,2,WEN ChengLin 1 & XU TingLiang 1 1 School of Automation,hangzhou Dianzi university,hangzhou 310018,china 2.state key laboratory of industrial control technology,zhejiang university,hangzhou 31.02.,china 1. School of Automation Hangzhou Dianzi University Hangzhou 310018 China2. State Key Laboratory of Industrial Control Technology Zhejiang University Hangzhou 310027 China

Kalman filter is a powerful tool in target tracking and self-localization across wireless sensor networks with many *** paper considers the filters design for networked systems with combined constraints of bandwidth and random delay,and proposes a kind of universal networked Kalman estimator for given linear time invariant(LTI) or determinate parameters(DP) systems,which are also called linear and determinate parameters(LDP) systems ***,two modeling ways to treat bit quantization error vector are given and the corresponding LDP systems taken after bit quantization are ***,we introduce an equivalent weighted summation form of the conventional linear Kalman filter,which fully uses two essential characteristics,namely offline computation property from the LDP systems and linear weighted summation property from the linear minimum mean square error ***,by adopting the replacement and innovation compensation operations,a kind of integrated networked estimator,involving two estimation algorithms with different modeling ways to bit quantization error actually,is presented based on the weighted summation filter for random delay *** proposed universal networked estimation algorithms have some outstanding advantages such as extensive application,concise algorithm structure,high estimate accuracy,and good running *** examples are demonstrated to validate the proposed networked estimation algorithms.

关键词： Kalman filter LDP systems LMMSE limited bandwidth random delay

Virtual Reality Based Process Integrated Simulation Platform in Refinery:Virtual Refinery and Its Application

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china Petroleum Processing & Petrochemical technology 2011年第3期13卷 74-84页

作者： Zhou Zewei Feng Yiping Rong Gang Wu Yucheng (state key laboratory of industrial control technology,Institute of Cyber-Systems and control,zhejiang university,hangzhou 31.02.,china) zhejiang Univ State Key Lab Ind Control Technol Inst Cyber Syst & Control Hangzhou 310027 Zhejiang Peoples R China

With the combination between system simulation and virtual reality,we have established an integrated virtual refinery simulation platform,and analyzed the overall design and principal *** paper introduces a simulation algorithm about a refinery based on virtual reality,and explains how the algorithm can be applied to the virtual refinery integrated simulation platform in *** virtual refinery simulation platform,which consists of a three-dimensional scene system,an integrated database system and a dynamic-static simulation system,has many applications,such as dynamic-static simulation of key process unit used as process control and oil tank blending simulation for *** the visualization and human-computer interaction for acquiring production and process data,this platform can provide effective supports on staff training related with monitoring,control and operation in *** refinery can also be web published through the internet and it is helpful for the distance training and education.

关键词： virtual refinery petrochemical enterprise process integrated simulation information representation intelligent manufacturing systems

P systems based multi-objective optimization algorithm

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Progress in Natural Science:Materials International 2007年第4期17卷 458-465页

作者： Huang Liang, He Xiongxiong, Wang Ning and Xie Yi ( National laboratory of industrial control technology, Institute of Advanced Process control, zhejiang university, hangzhou 31.02., china zhejiang university of technology, hangzhou 310033, china) [a]National laboratory of industrial control technology Institute of Advanced Process Control Zhejiang University Hangzhou China [b]zhejiang university of technology Hangzhou China

Based on P systems, this paper proposes a new multi-objective optimization algorithm (PMOA). Similar to P systems, PMOA has a cell-like structure. The structure is dynamic and its membranes merge and divide at different stages. The key rule of a membrane is the communication rule which is derived from P systems. Mutation rules are important for the algorithm, which has different ranges of mutation in different membranes. The cooperation of the two rules contributes to the diversity of the population, the conquest of the muhimodality of objective function and the convergence of algorithm. Moreover, the unique structure divides the whole population into several sub populations, which decreases the computational complexity. Almost a dozen popular algorithms are compared using several test problems. Simulation results illustrate that the PMOA has the best performance. Its solutions are closer to the true Pareto-optimal front

关键词： P systems evolutionary algorithm multi-objective optimization Pareto optimality.

Modified extremal optimization for the hard maximum satisfiability problem

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Journal of zhejiang university-Science C(Computers and Electronics) 2011年第7期12卷 589-596页

作者： Guo-qiang ZENG 1,Yong-zai LU 2,Wei-Jie MAO 2 (1 College of Physics & Electronic Information Engineering,Wenzhou university,Wenzhou 325035,china) (2.state key laboratory of industrial control technology,Institute of Cyber-Systems and control,zhejiang university,hangzhou 31.02.,china) College of Physics & Electronic Information Engineering Wenzhou University state key laboratory of industrial control technology Institute of Cyber-Systems and Control Zhejiang University

Based on our recent study on probability distributions for evolution in extremal optimization (EO),we propose a modified framework called EOSAT to approximate ground states of the hard maximum satisfiability (MAXSAT) problem,a generalized version of the satisfiability (SAT) *** basic idea behind EOSAT is to generalize the evolutionary probability distribution in the Bose-Einstein-EO (BE-EO) algorithm,competing with other popular algorithms such as simulated annealing and *** results on the hard MAXSAT instances from SATLIB show that the modified algorithms are superior to the original BE-EO algorithm.

关键词： Extremal optimization (EO) Evolution Probability distributions Maximum satisfiability (MAXSAT) problem

STRUCTURAL PARAMETERS CALIBRATION BY POSTURE MEASUREMENT ON PARALLEL 6-DOF PLATFORM

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Chinese Journal of Mechanical Engineering 2002年第4期15卷 334-338,343页

作者： Wu Jiangning Li Shilunstate key laboratory of Fluid Power Transmission and control, zhejiang university,hangzhou 31.02., china state key laboratory of Fluid Power Transmission and control Zhejiang University Hangzhou 310027 China

Some approaches to measure parallel 6-degree of freedom platform's posturestatically and to calibrate the platform's actual structural parameters by measuring a series of theplatform's varying postures are studied. In the case where high posture accuracy is requiredrelatively, to obtain the platform's actual structural parameters is very important. Threedimensions measurement with 2 theodolites are used to obtain the platform's postures statically andNewton iterative method is adopted to calibrate structural parameters. Some measures taken in themeasurement and the calibration are discussed in detail. And the experiment results of theplatform's posture control before and after the calibration are given. The results show that theplatform's posture control accuracy after the calibration is improved notably.

关键词： parallel 6-DOF platform theodolite posture measurement nonlinearequation group structural parameters calibration

DISTANCE MEASURING MODELING AND ERROR ANALYSIS OF DUALCCD VISION SYSTEM SIMULATING HUMAN EYES AND NECK

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Chinese Journal of Mechanical Engineering 2003年第4期16卷 396-399页

作者： Wang XuanyinXiao BaopingPan Fengstate key laboratory of Fluid PowerTransmission and control,zhejiang university,hangzhou 31.02., china zhejiang university State Key Laboratory of Fluid Power Transmission and Control Hangzhou 310027

A dual-CCD simulating human eyes and neck (DSHEN) vision system is putforward. Its structure and principle are introduced. The DSREN vision system can perform somemovements simulating human eyes and neck by means of four rotating joints, and realize preciseobject recognizing and distance measuring in all orientations. The mathematic model of the DSHENvision system is built, and its movement equation is solved. The coordinate error and measureprecision affected by the movement parameters are analyzed by means of intersection measuringmethod. So a theoretic foundation for further research on automatic object recognizing and precisetarget tracking is provided.

关键词： Dual-CCD Simulating human eyes and neck (DSHEN) Intersection measure Erroranalysis Homogeneous coordinate transformation

Time-delayed feedback control optimization for quasi linear systems under random excitations

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Acta Mechanica Sinica 2009年第3期25卷 395-402页

作者： Xueping Li Demin Wei Weiqiu Zhu School of Civil Engineering and Transportation, South china university of technology, 510640 Guangzhou, china Department of Mechanics, state key laboratory of Fluid Power Transmission and control, zhejiang university, 31.02. hangzhou, china School of Civil Engineering and Transportation South China University of Technology 510640 Guangzhou China Department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University 310027 Hangzhou China

A strategy for time-delayed feedback control optimization of quasi linear systems with random excitation is proposed. First, the stochastic averaging method is used to reduce the dimension of the state space and to derive the stationary response of the system. Secondly, the control law is assumed to be velocity feedback control with time delay and the unknown control gains are determined by the performance indices. The response of the controlled system is predicted through solving the Fokker-Plank-Kolmogorov equation associated with the averaged Ito equation. Finally, numerical examples are used to illustrate the proposed control method, and the numerical results are confirmed by Monte Carlo simulation .

关键词： Quasi linear system Time-delayed feedback Stochastic averaging method Random excitation