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IEEE Instrumentation and Measurement Technology Conference

作者： Tao Sun Hongjian Zhang Chiying Hu Department of Control Science and Engineering National Key Laboratory of Industrial Control Technology University of Zhejiang Hangzhou China

A novel scheme to identify flow regime and measure quality in gas-liquid two-phase using differential pressure signal is proposed. Flow regime is identified based on wavelet analysis and back-propagation (BP) neural network. Nine-scale Haar wavelet decomposition is performed on differential pressure signal. The scale energy ratio is extracted as the input of BP network to identify flow regime. Based on the flow regime information, relation between quality and pressure signal is fitted by polynomial. Experiments show that in annular flow, the polynomial fits well.

关键词： Wavelet analysis Fluid flow measurement Signal processing Testing Neural networks Polynomials Signal analysis Chemical industry Pressure measurement Data acquisition

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Time-delay neural network for the prediction of carbonation tower's temperature

Time-delay neural network for the prediction of carbonation ...

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IEEE Instrumentation and Measurement Technology Conference

作者： Dan Shi Hongjian Zhang Liming Yang Institute of Automation Instrumentation Department of Control Science and Engineering University of Zhejiang Hangzhou China

The carbonation column is a key reactor to manufacture synthetic soda ash using the Solvay process. Because of the complexity of the reaction in the column, it is difficult to control such a nonlinear large-time-delay system with normal measurement instrument. To solve this problem, time-delay neural network (TDNN) is used in the soft measurement model in this paper. A special back-propagation (BP) algorithm is developed to train the neural network. Comparing with the model based on multi-layered perceptron (MLP), it is shown that TDNN can describe the system's dynamic character better, and predict much more precisely. The influences of the input variables to the output of the model are analyzed with the online data. Analysis results show this model matches the reaction kinetics and the real operating condition.

关键词： Neural networks Temperature Inductors Manufacturing processes Ash Nonlinear control systems control systems Instruments Predictive models Multilayer perceptrons

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A PREDICTOR-CORRECTOR INTERIOR-POINT ALGORITHM FOR CONVEX QUADRATIC PROGRAMMING

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Numerical Mathematics A Journal of Chinese Universities(English Series) 2002年第1期11卷 52-62页

作者： Liang Ximing(梁昔明) Qian Jixin(钱积新) College of Information Science ＆ Engineering Central South University Changsha 410083 Institute of Systems Engineering National Lab of Industrial Control Technology Zhejiang University Hangzhou 310027

The simplified Newton method, at the expense of fast convergence, reduces the work required by Newton method by reusing the initial Jacobian matrix. The composite Newton method attempts to balance the trade-off between expense and fast convergence by composing one Newton step with one simplified Newton step. Recently, Mehrotra suggested a predictor-corrector variant of primal-dual interior point method for linear programming. It is currently the interiorpoint method of the choice for linear programming. In this work we propose a predictor-corrector interior-point algorithm for convex quadratic programming. It is proved that the algorithm is equivalent to a level-1 perturbed composite Newton method. Computations in the algorithm do not require that the initial primal and dual points be feasible. Numerical experiments are made.

关键词： convex quadratic programming, interior-point methods, predictor-corrector algorithms, numerical experiments.

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Robustness of discrete nonlinear systems with open-closed-loop iterative learning control

Robustness of discrete nonlinear systems with open-closed-lo...

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International Conference on Machine Learning and Cybernetics (ICMLC)

作者： Dao-Ying Pi K. Panaliappan Department of Control Science and Engineering University of Zhejiang Hangzhou China Department of computer Engineering & Computer Science University of Missouri Columbia MO USA

In this paper, iterative learning control problem is investigated for a class of time-varying discrete nonlinear systems in the presence of different disturbances. Conditions for guaranteeing the robustness of an open-closed-loop iterative learning control system are presented. It is shown that the tracking errors of the control system are uniformly bounded in the presence of bounded state uncertainty, output disturbance and initial state error. The system can track the desired trajectory completely if all the uncertainties are gradually repeated. The conditions show that most coefficients of the iterative learning controller have no effects on the system robustness.

关键词： Robust control Nonlinear systems Nonlinear control systems control systems Uncertainty Robustness Sufficient conditions Time varying systems Feedback control Trajectory

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An information theoretic interpretation for H/sub /spl infin// entropy

An information theoretic interpretation for H/sub /spl infin...

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IEEE International Symposium on Computer Aided control System Design (CACSD)

作者： Hui Zhang Youxian Sun Department of Control Science & Engineering College of lnformation Science & Engineering National Lobororory of Industrial Conrrol Technology Zhejiang University Hangzhou China

The relation between mutual information rate of system variables and system H/sub /spl infin// entropy is formulated, and an information theoretic interpretation of the minimum entropy H/sub /spl infin// control metho... 详细信息

ISBN: (纸本)078037388X

关键词： Entropy Mutual information control systems Transfer functions Equations Information theory System identification Random processes Research and development Density functional theory

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Optimal floating-point realizations of finite-precision digital controllers

Optimal floating-point realizations of finite-precision digi...

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IEEE Conference on Decision and control

作者： Jun Wu Sheng Chen J.F. Whidborne Jian Chu National Key Laboratory of Industrial Control Technology Institute of Advanced Process Control University of Zhejiang Hangzhou China Department of Electronics and Computer Science University of Southampton Southampton UK Department of Mechanical Engineering King''s College London UK

ISBN: (纸本)0780375165

The paper investigates the closed-loop stability issue of finite-precision realizations for digital controllers implemented in floating-point arithmetic. Unlike the existing methods which only address the effect of the mantissa bits in floating-point format to the sensitivity of closed-loop stability, the sensitivity of closed-loop stability is analyzed with respect to both the mantissa and exponent bits of floating-point format. A computationally tractable finite word length (FWL) closed-loop stability measure is defined, and the optimal controller realization problem is posed as searching for a floating-point realization that maximizes the proposed measure. A numerical optimization approach is adopted to solve for the resulting optimization problem. Simulation results show that the proposed design procedure yields computationally efficient controller realizations with enhanced FWL closed-loop stability performance.

关键词： Optimal control Digital control Stability Floating-point arithmetic Length measurement Design methodology Uncertainty Laboratories Industrial control Process control

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Global optimal realizations of finite precision digital controllers

Global optimal realizations of finite precision digital cont...

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IEEE Conference on Decision and control

作者： Jun Wu Sheng Chen Gang Li Jian Chu National Key Laboratory of Industrial Control Technology University of Zhejiang Hangzhou China Department of Electronics and Computer Science University of Southampton Southampton UK School of Electrical and Electronic Engineering Nanyang Technological University Singapore

ISBN: (纸本)0780375165

The paper analyzes global solutions to the optimal digital controller realization problem based on maximizing a finite word length (FWL) closed-loop stability measure. For each closed-loop eigenvalue, a single-pole FWL stability function is first introduced, and a single-pole FWL stability measure is then defined as the maximum of the corresponding single-pole stability function over all the controller realizations. It is shown that the minimum of the single-pole stability measures for all the closed-loop eigenvalues is an upper bound of the optimal value for the optimal realization problem. An analytical method to compute a single-pole stability measure is developed, and an expression for all the realizations which achieve a given single-pole measure is derived. When a realization, which is a solution of the minimum single-pole measure, further satisfies the condition that the values of all its single-pole stability functions are not less than the minimum single-pole measure, the minimum single-pole measure is the optimal value of the optimal realization problem and this realization is the solution for the optimal realization problem. A computationally simple algorithm is presented.

关键词： Optimal control Digital control control systems Stability analysis Eigenvalues and eigenfunctions Uncertainty Laboratories Industrial control Industrial electronics Computer science

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An intelligent measurement system for powder flowrate measurement in pneumatic conveying system

An intelligent measurement system for powder flowrate measur...

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IEEE Instrumentation and Measurement Technology Conference

作者： Zhiyao Huang Baoliang Wang Haiqing Li National Key Laboratory of Industrial Control Technology Department of Control Science and Engineering University of Zhejiang Hangzhou China

ISBN: (纸本)0780366468

A novel method for the on-line measurement of powder flowrate in pneumatic conveying system is proposed. It is a nonrestrictive method based on the measurement values of total pressure drop of gas-solid two-phase flow and the powder concentration, and also has the advantage of simplicity, reliability and low cost. An intelligent measurement system for the powder flowrate measurement is developed. The experimental results show that the maximum measurement error is satisfactory for industrial application.

关键词： Intelligent systems Powders Transducers Fluid flow measurement Intelligent sensors Measurement units Temperature sensors Costs Electrical equipment industry Data acquisition

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Application of electrical capacitance tomography to the void fraction measurement of two-phase flow

Application of electrical capacitance tomography to the void...

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IEEE Instrumentation and Measurement Technology Conference

作者： Zhiyao Huang Baoliang Wang Haiqing Li National Key Laboratory of Industrial Control Technology Department of Control Science and Engineering University of Zhejiang Hangzhou China

ISBN: (纸本)0780366468

Based on electrical capacitance tomography technique, a new method for the void fraction measurement of two-phase flow is proposed. A void function measurement system is established, A mathematical model of image reconstruction of electrical capacitance tomography is developed. To obtain the quantitative information of two-phase flow, a new image reconstruction algorithm is presented. The experimental results show that the accuracy of void fraction measurement is satisfactory. The proposed method is suitable for the void fraction measurement of many kinds of two-phase flow.

关键词： Electrical capacitance tomography Capacitance measurement Fluid flow measurement Electric variables measurement Image reconstruction Dielectric measurements Permittivity measurement Electrodes Data acquisition Phase measurement

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Two-step method for gross error detection in process data

Two-step method for gross error detection in process data

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American control Conference (ACC)

作者： Jian Chen Zheng Chen Hongye Su Jian Chu National Laboratory of Industrial Control Technology Institute of Advanced Process Control Department of System Science and Engineering Zhejiang University of Technology Hangzhou China Department of System Science and Engineering Zhejiang University Hangzhou P. R. China National Laboratory of Industrial Control Technology stitute of Advanced Process Control Zhejiang University of Technology Hangzhou China

Three types of gross errors-measurement biases, process leaks, and abnormal variances-are discussed. A new class of test statistics for gross error detection, called the two-step method, is proposed. This method consists of two steps. The first step is to detect and eliminate the abnormal variances in measured variables. The second step is to detect measurement biases and process leaks. In the second step, a mean-value transformation is introduced to improve the performance of gross error detection. Simulations are performed, and the two-step method is compared to the existing test statistics. It is shown that the new tests have a superior overall performance, and can detect all three types of gross errors discussed in this paper, even gross errors of small magnitudes. Also, the two-step method can easily distinguish measurement biases and process leaks from abnormal variances.

关键词： Testing Q measurement Fluid flow measurement Statistical analysis Error analysis Instruments Steady-state Laboratories Industrial control Process control

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