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Ding, Limei
Publications (10 of 14) Show all publications
Ding, L., Johansson, A. & Gustafsson, T. (2009). Application of reduced models for robust control and state estimation of a distributed parameter system (ed.). Paper presented at . Journal of Process Control, 19(3), 539-549
Open this publication in new window or tab >>Application of reduced models for robust control and state estimation of a distributed parameter system
2009 (English)In: Journal of Process Control, ISSN 0959-1524, E-ISSN 1873-2771, Vol. 19, no 3, p. 539-549Article in journal (Refereed) Published
Abstract [en]

This paper studies the application of reduced models of a distributed parameter system for robust process control and state estimation. We take the approach of integrating model reduction, parameter identification, and model uncertainty analysis, in purpose to find an appropriate trade-off between complexity and robust performance. The application example is the temperature system in a continuous paper pulp digester. Physical modeling of this process results in coupled linearized partial differential equations which are then reduced into low-order nominal process models using an orthogonal collocation approximation method.Two different approaches to obtaining a model uncertainty description are adapted for use on a distributed parameter system with low-order nominal model and shown to produce similar results when tested with measurement data. It is also demonstrated how this uncertainty description, in combination with the reduced model, may be used for robust control design and verification of the control performance on the distributed parameter system.Finally, the possibility of estimating the distributed process state using a state observer for the reduced process is demonstrated. Measurements of the process state in a certain position is available and is shown to agree with the estimated state at the same position.

National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-12280 (URN)10.1016/j.jprocont.2008.04.009 (DOI)000264648800017 ()2-s2.0-60649084188 (Scopus ID)b63f6f50-4378-11dd-bfd7-000ea68e967b (Local ID)b63f6f50-4378-11dd-bfd7-000ea68e967b (Archive number)b63f6f50-4378-11dd-bfd7-000ea68e967b (OAI)
Note
Validerad; 2009; 20080626 (andreasj)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Ding, L., Gustafsson, T. & Johansson, A. (2007). Model parameter estimation of simplified linear models for a continuous paper pulp digester (ed.). Paper presented at . Journal of Process Control, 17(2), 115-127
Open this publication in new window or tab >>Model parameter estimation of simplified linear models for a continuous paper pulp digester
2007 (English)In: Journal of Process Control, ISSN 0959-1524, E-ISSN 1873-2771, Vol. 17, no 2, p. 115-127Article in journal (Refereed) Published
Abstract [en]

A physical model of a continuous paper pulp digester is simplified and two subprocesses selected from the digester are modelled by coupled linear partial differential equations. This study focuses on the parameter identification of the simplified linear models. Finite-dimensional approximation of the model is made and a software package developed for identification of distributed parameter processes is applied. This identification system is developed for flexibility to allow identification for different choices of subprocesses and process variables. Unknown parameters of the subprocess models are estimated and the results are illustrated by process simulation and model validation.

National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-3112 (URN)10.1016/j.jprocont.2006.09.003 (DOI)000244588300003 ()2-s2.0-33846616356 (Scopus ID)0e56b5e0-78e1-11db-962b-000ea68e967b (Local ID)0e56b5e0-78e1-11db-962b-000ea68e967b (Archive number)0e56b5e0-78e1-11db-962b-000ea68e967b (OAI)
Note
Validerad; 2007; 20061120 (ysko)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Ding, L., Gustafsson, T. & Johansson, A. (2007). Physical model parameter estimation of a nonlinear process (ed.). In: (Ed.), (Ed.), Proceedings of the 2006 IEEE International Conference on Control Applications Applications: Munich, Germany, 4 - 6 October 2006. Paper presented at IEEE International Conference on Control Applications : 04/10/2006 - 06/10/2006 (pp. 2933-2938). Piscataway, NJ: IEEE Communications Society
Open this publication in new window or tab >>Physical model parameter estimation of a nonlinear process
2007 (English)In: Proceedings of the 2006 IEEE International Conference on Control Applications Applications: Munich, Germany, 4 - 6 October 2006, Piscataway, NJ: IEEE Communications Society, 2007, p. 2933-2938Conference paper, Published paper (Refereed)
Abstract [en]

A physical model of a nonlinear subprocess in a continuous paper pulp digester is discussed and simplified. Model approximation is carried out in order to produce a simple linear model to be used for unknown parameter estimation of the physical model. The Taylor series expansion and the orthogonal collocation method are applied for the model linearization and model lumping, respectively. The reduced model is expressed as a standard state space form. The model parameters are estimated in the least squares sense, and the parameters retain their own physical meanings. The results of the parameter estimation are discussed and the model is verified using validation data.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE Communications Society, 2007
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-35921 (URN)10.1109/CCA.2006.286075 (DOI)2-s2.0-43049166014 (Scopus ID)aa788f50-86b2-11db-8975-000ea68e967b (Local ID)0-7803-9795-9 (ISBN)aa788f50-86b2-11db-8975-000ea68e967b (Archive number)aa788f50-86b2-11db-8975-000ea68e967b (OAI)
Conference
IEEE International Conference on Control Applications : 04/10/2006 - 06/10/2006
Note
Godkänd; 2007; 20061121 (evan)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-07-10Bibliographically approved
Ding, L., Gustafsson, T. & Johansson, A. (2006). Model identification of a nonlinear subprocess in a continuous paper pulp digester (ed.). In: (Ed.), Risto Ritala (Ed.), Measurement and control - applications for the operator: Control Systems 2006, June 6-8, 2006, Tampere Finland. Paper presented at Control Systems 2006 : 06/06/2006 - 08/06/2006. : Finnish Society of Automation
Open this publication in new window or tab >>Model identification of a nonlinear subprocess in a continuous paper pulp digester
2006 (English)In: Measurement and control - applications for the operator: Control Systems 2006, June 6-8, 2006, Tampere Finland / [ed] Risto Ritala, Finnish Society of Automation , 2006Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Finnish Society of Automation, 2006
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-37665 (URN)bbff8da0-9765-11db-8975-000ea68e967b (Local ID)952-5183-26-2 (ISBN)bbff8da0-9765-11db-8975-000ea68e967b (Archive number)bbff8da0-9765-11db-8975-000ea68e967b (OAI)
Conference
Control Systems 2006 : 06/06/2006 - 08/06/2006
Note
Godkänd; 2006; 20061229 (ysko)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-12-15Bibliographically approved
Ding, L. & Gustafsson, T. (2001). Control of a delay system using robust finite-dimensional controller (ed.). In: (Ed.), (Ed.), CSEE '2001: Conference Proceedings. Paper presented at Annual Symposium on Computer Science and Electrical Engineering : 20/05/2001 - 21/05/2001. : Luleå tekniska universitet
Open this publication in new window or tab >>Control of a delay system using robust finite-dimensional controller
2001 (English)In: CSEE '2001: Conference Proceedings, Luleå tekniska universitet, 2001Conference paper, Published paper (Other academic)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2001
Series
Technical report / Luleå University of Technology, ISSN 1402-1536 ; 2001:09
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-35332 (URN)9d356c80-c1bf-11db-9ea3-000ea68e967b (Local ID)9d356c80-c1bf-11db-9ea3-000ea68e967b (Archive number)9d356c80-c1bf-11db-9ea3-000ea68e967b (OAI)
Conference
Annual Symposium on Computer Science and Electrical Engineering : 20/05/2001 - 21/05/2001
Note
Godkänd; 2001; 20070221 (ysko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Ding, L. & Gustafsson, T. (2000). Dynamic modeling of flotation circuits (ed.). In: (Ed.), Sirkka-Liisa Jämsä-Jounela (Ed.), Future Trends in Automation in Mineral and Metal Processing: a proceedings volume from the IFAC workshop / MM 2000, Finland, 22-24 August 2000. Paper presented at IFAC Workshop on Future Trends in Automation in Mining and Metal Processing : 22/08/2000 - 24/08/2000 (pp. 197-202). Kidlington: Pergamon Press
Open this publication in new window or tab >>Dynamic modeling of flotation circuits
2000 (English)In: Future Trends in Automation in Mineral and Metal Processing: a proceedings volume from the IFAC workshop / MM 2000, Finland, 22-24 August 2000 / [ed] Sirkka-Liisa Jämsä-Jounela, Kidlington: Pergamon Press, 2000, p. 197-202Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Kidlington: Pergamon Press, 2000
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-37133 (URN)b0ab5b70-50be-11db-9592-000ea68e967b (Local ID)80436226 (ISBN)b0ab5b70-50be-11db-9592-000ea68e967b (Archive number)b0ab5b70-50be-11db-9592-000ea68e967b (OAI)
Conference
IFAC Workshop on Future Trends in Automation in Mining and Metal Processing : 22/08/2000 - 24/08/2000
Note
Godkänd; 2000; 20060930 (ysko)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Ding, L. & Gustafsson, T. (2000). Dynamic modeling of flotation circuits (ed.). Paper presented at IFAC Workshop on Future Trends in Automation in Mining and Metal Processing : 22/08/2000 - 24/08/2000. Elsevier IFAC Publications / IFAC Proceedings series, 197-202
Open this publication in new window or tab >>Dynamic modeling of flotation circuits
2000 (English)In: Elsevier IFAC Publications / IFAC Proceedings series, ISSN 1474-6670, p. 197-202Article in journal (Refereed) Published
Abstract [en]

The modeling of flotation is a difficult task due to the influences of mineralogical features of ores, floatability of various minerals governed by pulp environments, flotation kinetics and hydrodynamic variables. In the paper the dynamic modeling of flotation is studied. Based on the first order flotation rate equation, the dynamic description of a continuous flotation process is obtained both for a single continuous flotation cell and n cells arranged in series. A dynamic model for the multi-component case of continuous flotation is also discussed. The models obtained give the dynamic behaviors when the flotation parameters are changed due to the variation of the chemical and physical environment

Place, publisher, year, edition, pages
Kidlington: Pergamon Press, 2000
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-63552 (URN)10.1016/S1474-6670(17)36991-4 (DOI)
Conference
IFAC Workshop on Future Trends in Automation in Mining and Metal Processing : 22/08/2000 - 24/08/2000
Available from: 2017-05-26 Created: 2017-05-26 Last updated: 2017-11-29Bibliographically approved
Ding, L. (2000). On modeling and control of complex dynamic systems (ed.). (Licentiate dissertation). Paper presented at . Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>On modeling and control of complex dynamic systems
2000 (English)Licentiate thesis, monograph (Other academic)
Abstract [en]

Nonlinear complex multi-input multi-output process is very troublesome to control. It is usually also ill-modeled. The problem of such process both in control and modeling requires a comprehensive utilization of various techniques. The thesis presents the methods for the modeling and control of complex systems. A typical example of complex processes is mineral flotation that characterized by multivariable, nonlinearities, strong interactions, stochastic disturbances, and large and variable delay times. The dynamic nonlinear model of a inverse continuous flotation process is developed based on the first order kinetics. The complexity of mineral flotation in modeling and control is shown by the analysis of the dynamic model and the relation between the process inputs and the process parameters. As an attractive alternative of conventional control technologies, fuzzy logic control is discussed for the control of an MIMO nonlinear flotation system and the simulation of the control system is carried out. LQG optimal control of the pulp level, a subsystem in a flotation process is studied and the robustness is analyzed based on the structured singular value. The control of infinite dimensional systems is known to all a knotty problem. Orthogonal collocation method, which is one of the methods of weighted residual, is employed to reduce the infinite dimensional model of the systems. In a case study a time delay system is approximated using the orthogonal collocation and a robust controller of the delay system is synthesized based on the method introduced by Glover and McFarlane in 1989. The robustness degradation caused by model reduction is discussed. The results show that the strategies studied in the thesis are available to solve the relevant modeling and control problems of complex systems.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2000. p. 107
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757 ; 2000:03
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-26097 (URN)ca340010-d57f-11db-8550-000ea68e967b (Local ID)ca340010-d57f-11db-8550-000ea68e967b (Archive number)ca340010-d57f-11db-8550-000ea68e967b (OAI)
Note

Godkänd; 2000; 20070318 (ysko)

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-24Bibliographically approved
Ding, L. & Gustafsson, T. (2000). Robustness of a pulp level control system (ed.). In: (Ed.), (Ed.), Reglermöte: preprints. Paper presented at Reglermöte 2000 : 06/06/2000 - 08/06/2000. Uppsala
Open this publication in new window or tab >>Robustness of a pulp level control system
2000 (English)In: Reglermöte: preprints, Uppsala, 2000Conference paper, Published paper (Other academic)
Place, publisher, year, edition, pages
Uppsala: , 2000
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-34104 (URN)83749760-5227-11db-9592-000ea68e967b (Local ID)83749760-5227-11db-9592-000ea68e967b (Archive number)83749760-5227-11db-9592-000ea68e967b (OAI)
Conference
Reglermöte 2000 : 06/06/2000 - 08/06/2000
Note
Godkänd; 2000; 20110504 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Ding, L., Gustafsson, T. & Su, F. (1999). Application of fuzzy control to a flotation process (ed.). In: (Ed.), Han-Fu Chen (Ed.), Proceedings of the 14th World Congress: International Federation of Automatic Control : Beijing, P.R. China, 5 - 9 July 1999. Paper presented at World Congress of IFAC : 05/07/1999 - 09/07/1999 (pp. 391-396). Kildington: Publ. for the International Federation of Automatic Control by Pergamon,
Open this publication in new window or tab >>Application of fuzzy control to a flotation process
1999 (English)In: Proceedings of the 14th World Congress: International Federation of Automatic Control : Beijing, P.R. China, 5 - 9 July 1999 / [ed] Han-Fu Chen, Kildington: Publ. for the International Federation of Automatic Control by Pergamon, , 1999, p. 391-396Conference paper, Published paper (Refereed)
Abstract [en]

The application of fuzzy logic in the control of flotation is studied in this paper. A general description of apatite flotation process is given and a dynamic model is developed. A fuzzy logic controller is proposed for a nonlinear isolated continuous flotation process. The knowledge base of the controller is constructed on the basis of the semi-batch results from the apatite flotation experiments and available knowledge sources. The design of the controller does not need an exact process model. The simulation result shows that the fuzzy logic controller can reduce collector dosage consumption of the apatite flotation process while maintaining the phosphorous content in magnetite concentrate within an acceptable limits less than 0.025% P. Stability of the fuzzy control system is discussed

Place, publisher, year, edition, pages
Kildington: Publ. for the International Federation of Automatic Control by Pergamon,, 1999
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-35115 (URN)9858bf80-6771-11db-8cbe-000ea68e967b (Local ID)0-08-043225-5 (ISBN)9858bf80-6771-11db-8cbe-000ea68e967b (Archive number)9858bf80-6771-11db-8cbe-000ea68e967b (OAI)
Conference
World Congress of IFAC : 05/07/1999 - 09/07/1999
Note
Godkänd; 1999; 20061029 (ysko)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
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