Optimal Real-time Control Of Sewer Networks

by MARINAKI, MAGDALENE; Papageorgiou, Markos

• ISBN13: 9781852338947
• ISBN10: 1852338946
• Format: Hardcover
• Copyright: 2004-12-01
• Publisher: Springer-Verlag New York Inc

Summary

Recent years have seen a very marked increase in the desire to protect the environment from any and all malign influences. The maintenance or restoration of water quality is a vital part of that protection. A sine qua non of control system development for modern sewer networks is therefore the preservation of the water system around a networka??s outflow(s). Several approaches have been proposed for the optimisation of sewage control and Optimal Real-time Control of Sewer Networks provides a comparative synthesis of a central sewer network flow control based on two of these: nonlinear-optimal and multivariable-feedback control. In nonlinear optimal control, control and operational objectives are treated directly by the formulation of a nonlinear cost function minimized according to system constraints and the relevant state equation. The comparison presented uses the rolling horizon method for the real-time application of the optimal control algorithm with updated inflow predictions and updated initial conditions. On the other hand, the linear multivariable feedback regulator a?? considered with and without feedforward terms to account for external inflows a?? is developed via a systematic linear-quadratic procedure including precise specifications on model structure, equations and the choice of nominal steady state and quadratic criterion. The comprehensive testing and comparison of these protocols is undertaken on the basis of their respective control results for the real large-scale sewer network located around the river Obere Iller in Bavaria. The control strategies now implemented within this network are based on this study. Starting at the selection of possible methods of control and moving to the actual implementation of those methods in a real sewer system, Optimal Real-time Control of Sewer Networks will be invaluable to control and civil engineers working in sewage flow and wastewater treatment and of great interest to academics wishing to see how their ideas on optimal control are likely to work out when practically applied.

Author Biography

Magdalene Marinaki was born in Chania, Greece. In 1993, she received the Dipl.- Eng. degree in Production Engineering and Management from the Technical University of Crete, Greece, while she received the M. Sc. and Ph. D. degrees in Production Engineering and Management from the same University in 1995 and 2002, respectively. She received a scholarship by the Institute of National Scholarships and the Technical Chamber of Greece in the academic year 1991-1992 for high performance in her studies. Since March 1994, she has been a Research and Teaching Associate of the Dynamic Systems and Simulation Laboratory of the Technical University of Crete. She has participated in research projects and she has assisted undergraduate courses. Since September 2000, she has been teaching at the Technological Educational Institute of Crete, Branch of Chania. Since September 2002, she has been a contract lecturer at the Technical University of Crete, Department of Production Engineering and Management. She is the author of research reports and papers in international journals and scientific conferences. Her research interests include optimal and automatic control, operations research and applications to water systems, transportation systems and further areas. She is a member of the Technical Chamber of Greece (TEE).Markos Papageorgiou was born in Thessaloniki, Greece, in 1953. He received the Diplom-Ingenieur and Doktor-Ingenieur (honors) degrees in Electrical Engineering from the Technical University of Munich, Germany, in 1976 and 1981, respectively. From 1976 to 1982 he was a Research and Teaching Assistant at the Control Engineering Chair, Technical University of Munich. He was a Free Associate with Dorsch Consult, Munich (1982-1988), and with Institute National de Recherche sur les Transports et leur S+¬curit+¬ (INRETS), Arcueil, France (1986-1988). From 1988 to 1994 he was a Professor of Automation at the Technical University of Munich. Since 1994 he has been a Professor at the Technical University of Crete, Chania, Greece. He was a Visiting Professor at the Politecnico di Milano, Italy (1982), at the Ecole Nationale des Ponts et Chauss+¬es, Paris (1985-1987), and at MIT, Cambridge (1997, 2000); and a Visiting Scholar at the University of Minnesota (1991, 1993), University of Southern California (1993) and the University of California, Berkeley (1993, 1997, 2001).Dr. Papageorgiou is the author of the books Applications of Automatic Control Concepts to Traffic Flow Modeling and Control (Springer, 1983) and Optimierung (Oldenbourg, 1991; 1996), the editor of the Concise Encyclopedia of Traffic and Transportation Systems (Pergamon Press, 1991), and the author or co-author of some 230 technical papers. His research interests include automatic control and optimization theory and applications to traffic and transportation systems, water systems and further areas. He is an Associate Editor of Transportation Research-Part C, of IEEE Transactions on Intelligent Transportation Systems and a member of the IEEE Control System Society, Conference Editorial Board, and Chairman of the IFAC Technical Committee on Transportation Systems. He is a member of the Technical Chamber of Greece (TEE) and a Fellow of IEEE. He received a DAAD scholarship (1971-1976), the 1983 Eugen-Hartmann award from the Union of German Engineers (VDI), and a Fulbright Lecturing/Research Award (1997).

Table of Contents

1 Introduction	1	(4)
2 Modelling of Sewer Network Flow	5	(22)
2.1 Introduction	5	(1)
2.2 Accurate Model of Sewer Networks	6	(7)
2.2.1 Link Elements	6	(4)
2.2.2 Reservoirs	10	(1)
2.2.3 Control Gates	11	(1)
2.2.4 Nodes	12	(1)
2.2.5 External Inflows	12	(1)
2.2.6 Treatment Plants	12	(1)
2.3 Simulation Tools for Sewer Networks	13	(3)
2.4 Simulation Program - KANSIM	16	(5)
2.4.1 Link Elements	16	(2)
2.4.2 Reservoirs	18	(1)
2.4.3 Control Gates	19	(1)
2.4.4 Nodes	19	(2)
2.4.5 External Inflows	21	(1)
2.4.6 Treatment Plants	21	(1)
2.5 Simplified Model of Sewer Networks	21	(6)
2.5.1 Link Elements	21	(1)
2.5.2 Reservoirs	21	(3)
2.5.3 Nodes	24	(1)
2.5.4 External Inflows	24	(1)
2.5.5 Treatment Plants	24	(1)
2.5.6 Integrated Simplified Model of the Sewer Network	24	(3)
3 Flow Control in Sewer Networks	27	(28)
3.1 Control Objectives	27	(1)
3.2 Multilayer Control System	28	(1)
3.3 Studies of Water Resource Systems	29	(4)
3.4 The Pursued Approach	33	(2)
4 Nonlinear Optimal Control	35	(20)
4.1 Performance Criterion	35	(2)
4.2 Mathematical Problem Formulation	37	(1)
4.3 Solution Algorithm	38	(13)
4.3.1 General Problem Formulation	38	(1)
4.3.2 Necessary Optimality Conditions	38	(2)
4.3.3 Structure of the Solution Algorithm	40	(1)
4.3.4 Specification of a Search Direction	41	(2)
4.3.5 Line Search Algorithm	43	(2)
4.3.6 Restart	45	(1)
4.3.7 Algorithm Comparisons	46	(2)
4.3.8 RPROP Algorithm	48	(3)
4.4 Rolling Horizon	51	(4)
5 Multivariable Feedback Control	55	(10)
5.1 General Problem Considerations	55	(1)
5.2 Linear-Quadratic Formulation of the Sewer Network Control Problem	56	(3)
5.3 Multivariable Control Law	59	(5)
5.3.1 General Problem Formulation	59	(1)
5.3.2 Necessary Optimality Conditions	60	(1)
5.3.3 Time-Variant Solution	60	(2)
5.3.4 Time-Invariant Solution	62	(2)
5.4 Computational Effort	64	(1)
6 Application Example	65	(16)
6.1 Application Network	65	(6)
6.2 External Inflows	71	(1)
6.3 Nonlinear Optimal Control	71	(5)
6.4 Linear-Quadratic Formulation	76	(2)
6.5 Simulation	78	(3)
7 Simulation Results	81	(66)
7.1 No-Control Case	81	(11)
7.2 Nonlinear Optimal Control	92	(29)
7.2.1 Optimal Control Tool	92	(2)
7.2.2 Open-Loop Application	94	(13)
7.2.3 Rolling Horizon Application	107	(14)
7.2.3.1 Investigated Cases	107	(1)
7.2.3.2 Rolling Horizon with Complete Inflow Information	107	(7)
7.2.3.3 Rolling Horizon with Incomplete Inflow Information	114	(7)
7.2.4 General Observations	121	(1)
7.3 Multivariable Regulator	121	(23)
7.3.1 Multivariable Regulator without Feedforward Terms	121	(2)
7.3.2 Multivariable Regulator with Feedforward Terms	123	(21)
7.3.2.1 Multivariable Regulator with Feedforward Terms and Accurate Inflow Predictions	127	(9)
7.3.2.2 Multivariable Regulator with Feedforward Terms and Inaccurate Inflow Predictions	136	(8)
7.4 Comparison Between Nonlinear Optimal Control and Multivariable Feedback Control	144	(1)
7.5 Concluding Remarks	145	(2)
8 Conclusions and Future Research	147	(4)
References	151	(6)
Author Profiles	157	(2)
Index	159