The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
G.a. Dumont - One of the best experts on this subject based on the ideXlab platform.
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Stability-preserving modification of Paper Machine cross-directional control near spatial domain boundaries
Proceedings of the 41st IEEE Conference on Decision and Control 2002., 2002Co-Authors: S. Mijanovic, G.e. Stewart, G.a. DumontAbstract:The optimal controller design for spatially distributed dynamical systems is greatly simplified when spatially invariant models are used. However, the true spatial boundary conditions of many practical systems, including Paper Machine cross-directional processes, disrupt the spatial invariance and potentially destabilize the control system if not taken into account. This Paper considers the design of stability preserving spatial boundary conditions for Paper Machine cross-directional controllers originally computed for idealized spatially invariant processes.
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Paper Machine data analysis and display using wavelet transforms
IEEE Industry Applications on Dynamic Modeling Control Applications for Industry Workshop, 1998Co-Authors: S. Mcleod, G.a. Dumont, Z. Nesic, E. Lofkrantz, I. ShawAbstract:This Paper describes preliminary results from tests comparing analysis and display of Paper Machine basis weight data using conventional methods with those obtained using the wavelet transform. It is shown that the wavelet data compares well with result obtained from a TAPIO Analyzer and that significant data compression allows detailed process data to be stored efficiently.
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Cross direction response identification and control of Paper Machine using continuous wavelet transform
Proceedings of the 1997 American Control Conference (Cat. No.97CH36041), 1997Co-Authors: J. Ghofraniha, G.a. DumontAbstract:This article presents a new approach to cross directional (CD) response identification and control on a Paper Machine based on continuous wavelet transform. The response shape developed as a surface wave originating from the slice lip deflection is used as the mother wavelet equation. Identification results with Paper Machine data shows that the method is effective. Application of the continuous wavelet to the CD control problem presents a new formulation of the control algorithm. The mapping process is eliminated in the new approach and replaced with a simple scaling operation.
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Estimation in Paper Machine control
IEEE Control Systems Magazine, 1993Co-Authors: X.g. Wang, G.a. DumontAbstract:The problem of online estimation of basis weight and moisture content in Paper Machines is discussed, and algorithms for separating cross Machine and Machine direction (MD) variations using scanned data are proposed. Because of its inherent nonlinearity, the moisture scheme uses a bootstrap algorithm, assuming known MD dynamics. For basis weight, the model linearity can be used to develop an extended Kalman filter to estimate the more complicated MD dynamics. Both algorithms have been tested on industrial data. Results from the basis-weight algorithm when applied to industrial scanned and stationary data collected from an operating Paper Machine show that a second order autoregressive moving average (ARMA) model gives the best fit to the data in terms of sum of squares of prediction errors and in terms of the whiteness of the residual. Furthermore, there is a very good agreement between the MD models estimated with the scanned data and the single point data.
W.p. Heath - One of the best experts on this subject based on the ideXlab platform.
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On-line sensing of Paper Machine wet-end properties: dry-line detector
IEEE Transactions on Control Systems Technology, 1997Co-Authors: A.p. Kjaer, P.e. Wellstead, W.p. HeathAbstract:This Paper is concerned with the task of sensing in web-forming process control loops. Conventional and newly proposed measurement techniques are discussed and a new type of measurement is suggested. The new measurement method adresses the problem of Paper Machine "wet-end" sensing and is based on a CCD camera system which can detect the dry-line. Both the theoretical and practical aspects of the invention are investigated and the sensing system is developed into a portable measurement system which is applied to a Paper Machine. The Paper Machine measurements are analyzed and presented using nonparametric techniques based on analysis of variance. Compared to traditional scanning gauge systems the dry-line detector allows for a large reduction in the transport delay, higher data density and sampling rate, and better Machine directional (MD), and cross-directional (CD) signal decomposition.
Heikki N. Koivo - One of the best experts on this subject based on the ideXlab platform.
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Estimation of Target Values for Grade Changes in Paper Machine
Industrial Applications of Soft Computing, 2020Co-Authors: Pauli Viljamaa, Heikki Peltonen, Heikki N. KoivoAbstract:Paper making is a continuous process, where up to 10 m wide Paper web is produced and fed through a Paper Machine (Fig. 1) at the speed up to 1800 m/min. The Paper Machine may produce Paper 300,000 tons per year stopping only for short annual maintenance breaks. These numbers are approximate but give an idea how large-scale system a Paper Machine is.
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Target value computing in Paper Machine grade changes by fuzzy system
Ninth IEEE International Conference on Fuzzy Systems. FUZZ- IEEE 2000 (Cat. No.00CH37063), 2000Co-Authors: Pauli Viljamaa, Heikki Peltonen, Heikki N. KoivoAbstract:A fuzzy system is proposed to compute new target values for low level controllers during grade changes in a Paper Machine. The fuzzy system is designed and tuned in co-operation with human operators of the Paper Machine. The design method utilizes both heuristic knowledge and estimation techniques based on input-output data. The input fuzzy sets and the rule base are initially designed verbally and thereafter fine-tuned by a least squares algorithm. An industrial example illustrates the iterative design process. It shows that transparency and a priori knowledge included in the model are preserved also during optimization of the fuzzy model.
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Multivariable PI Control of Industrial Paper Machine Headboxes
IFAC Proceedings Volumes, 1996Co-Authors: A.i. Nissinen, Heikki N. Koivo, T.j. HuhtelinAbstract:Abstract Production rates in modern Paper Machines are increasing all the time. This poses challenging requirements for control of different subprocesses in the Paper Machine, e.g. for the headbox. Currently, scalar controllers are used for headbox control in industrial practice almost everywhere. Headbox control has been a favorite example of multivariable control in many simulation and laboratory studies but not in industry. This Paper presents an application of multivariable PI controller to the Paper Machine headbox. The procedure takes into account the limited tests that can be performed in practice, simplicity in structure and tuning, and realization using modern distributed automation systems.
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Retention Modelling and Control in the Paper Machine WET End
IFAC Proceedings Volumes, 1993Co-Authors: T. Rantala, P. Tarhonen, Heikki N. KoivoAbstract:Abstract Retention control has largely remained unsolved, although it is one of the most important control loops still to be closed in the Paper Machine. In this Paper retention modelling is done using multivariable time-series approach. Based on careful selection of vanables and model structure, several new control strategies are developed. Different feedback controls are successfully tested on a pilot Paper Machine. It is believed to be the first time when successful retention control has been reported in the literature.
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Application of Neural Networks in the Detection of Breaks in a Paper Machine
IFAC Proceedings Volumes, 1992Co-Authors: T. Sorsa, Heikki N. Koivo, R. KorhonenAbstract:Abstract Modem Paper Machines are very large and complex. The good runnability of a Paper Machine is very desirable but hard to achieve. Breaks are one of the most important problems considering the runnability and the productivity of a Paper Machine. In this Paper we discuss the methods to detect situations, where the probability of a break is exceptionally high. Operators have usually some kind of feeling about situations, which can increase the probability of a break, but it is impossible to find a unique set of features which cause breaks. Our approach is to collect data from a production Paper Machine and then analyse the data. The measurement points have been selected in co-operation with the Paper Machine staff. Principal component analysis has been used to visualize the occurrence of breaks and the movements of the state of a Paper Machine. Because very little unique knowledge about breaks is available, we use unsupervised neural networks to classify the measurement data and to find situations which are sensitive to breaks. Kohonen self-organizing feature maps are suitable because they create classifications in which classes of similar features become near each other. This Paper has two major contributions. First the Paper describes the mathematical results for the detection of Paper Machine breaks and second the Paper presents a concrete application, not a simulation study, of the use of artificial neural networks.
Robert D. Lorenz - One of the best experts on this subject based on the ideXlab platform.
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Modeling and Evaluation of Paper Machine Coater Sections
2018 IEEE IAS Pulp Paper and Forest Industries Conference (PPFIC), 2018Co-Authors: Guillermo A. Ramirez, Anibal M. Valenzuela, Steve Pittman, Robert D. LorenzAbstract:Coaters sections are challenging to tune during the commissioning of a Paper Machine. This Paper presents a detailed mechanical-electrical model of a one-coater section which includes a linear, operating point model of the sheet in the different spans, all the drivetrain components, and the vector controlled ac drives. The sheet model considers tail widening as well as the effect of coating and drying on the sheet elastic constant, activation of the torque current control and the beginning of coating. The developed model allows for complete evaluation of the different transient events including Paper slack due to load impacts. Results show that the best performance of the drives is obtained operating the spans with even sheet tensions, which reduces and/or eliminates the operation of the drives in regeneration or braking zones.
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Computer-Aided Controller Setting Procedure for Paper Machine Drive Systems
Conference Record of 2007 Annual Pulp and Paper Industry Technical Conference, 2007Co-Authors: Anibal M. Valenzuela, John M. Bentley, Robert D. LorenzAbstract:This Paper presents a comprehensive, three-stage computer-based methodology for the initial setting of the speed and torque controllers for the drives of a Paper Machine. First, the controller gains are selected based on the figures-of-merit for the frequency and time domain responses of each drive to commands and disturbances. After that, the effect of the elastic shafts is considered evaluating the resonant frequencies and 2M (two-mass) system responses. Finally, the responses of each group of drives to the process commands and/or disturbances of interest are evaluated. The use of the proposed methodology will assure fast and well-behaved responses of each group of drives of the different sections of a Paper Machine, with minimal field adjustments.
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Evaluation of torsional oscillations in Paper Machine sections
IEEE Transactions on Industry Applications, 2005Co-Authors: Miguel A. Valenzuela, John M. Bentley, Robert D. LorenzAbstract:Torsional oscillations greatly affect performance and determine the bandwidth (BW) and damping of speed loops. Backlash due to gear reducers can also contribute to the triggering of oscillations, especially when the drive runs at very low load torque. This Paper presents a detailed evaluation of these effects in typical electro-mechanical drive trains applied to Paper Machine sections. The cases evaluated consider torsional oscillations in two-mass and three-mass systems, and the effect of shaft diameter and length on the resonance frequencies of three typical Paper Machine sections. Time domain response plots are evaluated to show the effect of speed response overshoot, reducer backlash, and step or ramp speed commands. Based on these results, mechanical design guidelines are given for the most significant drive train components in order to minimize torsional oscillations of the speed controlled drive system.
A.p. Kjaer - One of the best experts on this subject based on the ideXlab platform.
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On-line sensing of Paper Machine wet-end properties: dry-line detector
IEEE Transactions on Control Systems Technology, 1997Co-Authors: A.p. Kjaer, P.e. Wellstead, W.p. HeathAbstract:This Paper is concerned with the task of sensing in web-forming process control loops. Conventional and newly proposed measurement techniques are discussed and a new type of measurement is suggested. The new measurement method adresses the problem of Paper Machine "wet-end" sensing and is based on a CCD camera system which can detect the dry-line. Both the theoretical and practical aspects of the invention are investigated and the sensing system is developed into a portable measurement system which is applied to a Paper Machine. The Paper Machine measurements are analyzed and presented using nonparametric techniques based on analysis of variance. Compared to traditional scanning gauge systems the dry-line detector allows for a large reduction in the transport delay, higher data density and sampling rate, and better Machine directional (MD), and cross-directional (CD) signal decomposition.
