Model predictive control of resonance sensitive irrigation canals

Saving water is an economic and ecological need. One way to save water is to reduce losses in irrigation networks by canal automation. The goal of canal automation is to make the right amount of water to at arrive in the right time. In order to achieve this goal, one of the ways is controlling the gates in the irrigation network by some control algorithm. In this work the control of a specific type of canal pools is studied: short and flat pools that are prone to resonance. The downstream water level control of this type of canals is investigated using the example of the 3-reach laboratory canal of the Technical University of Catalonia. Numerical and experimental studies are carried out to investigate the following: the choice of models for predictive control, the possibility to achieve offset-free control while using gravity offtakes and the best choice of control action variables. The objective of this work is to develop a well performing centralized model predictive controller (MPC) for the laboratory canal that is able to handle known and unknown setpoint changes and disturbances, and also to draw further conclusions about controller design for this type of canals. A recently developed model for resonant canals, the Integrator Resonance, is implemented and successfully tested experimentally for the first time. A new method to achieve offset free control for model predictive control is developed and tested numerically and experimentally. A choice of control variables are tested: As opposed to the discharge which is generally used as the control action variable, a state space model is formulated by using the gate opening as control variable without the need of water level measurement downstream of the gates. The results are summarized and conclusions are presented for control of short and flat canals that are prone to resonance

SCADA and related technologies

Presented at SCADA and related technologies for irrigation district modernization, II: a USCID water management conference held on June 6-9, 2007 in Denver, Colorado.SCADA systems in irrigation districts have focused on remote monitoring and remote control. In many districts, the remote control is manual, but in others the automation of structures is enabled through the usage of distributed control for the automation of individual structures. This paper presents the concept of an expanded, "umbrella" SCADA system that will perform the standard functions of remote control and remote monitoring, and will also incorporate information flow in the field for operators. The umbrella SCADA system will mesh the equipment-equipment information into an equipment-program-personnel network

Experimental design and verification of a centralized controller for irrigation canals

This thesis aims to develop a predictive control for irrigation canals to improve the management of water resources. Water is necessary for life and it is a scarce good that we need for drinking, in the agriculture, etc. At the same time, it can constitute a serious threat in particular areas due to the difficulty to grow foods by the increasing of prolonged droughts. The agriculture holds an important part of the food chain and the water resources for agriculture are important, the problem is the water transport systems present low efficiencies in practice. The yield agriculture has to be optimized, because the goal of an operational water manager is to deliver the water to the irrigation sites accurately and efficiently. To improve the efficiency of the water transport systems is necessary to invest in automating the operation of irrigation canals. In order to fulfill these objectives, we define an overall control diagrams scheme in chapter 5 which splits the management of the canal control in different blocks. The management of a canal start from setting the demand delivery accurately taking into account the crops necessities during an irrigation cycle and establishing the gate trajectories for controlling the canal in each time step. In an ideal case, the system would be controlled but some factors which could deviated the desired state for the canal from the real canal state, as for instance, a disturbance introduced into the canal. In that circumstances, it would be necessary to introduce in our overall control diagram, other algorithms which could aid the watermaster to restore the desired state of the canal. These algorithms, developed and tested for us, are the CSI and GoRoSoBo algorithms. The first one defines a powerful tool in the management of a canal. The Watermaster establishes the gates positions and fixes the desired water level at checkpoints to fulfill a scheduled demand. In that sense, when someone introduce a disturbance into the canal perturbs the water level at checkpoints, so the scheduled deliveries cannot fulfilled by the watermaster. In such case, the water level measurements at these checkpoints could be sent to the CSI algorithms which calculates the real extracted flow and the current canal state along the canal, that is, the water level and velocity in all cross-sections of the canal. This task is performed by the CSI algorithm which has been designed in this thesis and tested in numerous numerical examples (chapter 7) and experimentally in a laboratory canal of the Technical University of Catalonia (chapter 8). The last one is the essential tool in the management of a canal, that is, a control algorithm operating in real-time. The GoRoSoBo algorithm (Gómez, Rodellar, Soler, Bonet) is a feedback control algorithm which calculates the optimum gates trajectories for a predictive horizon taking into account the current canal state obtained by CSI as well as the scheduled demands and the previous gate trajectories. GoRoSoBo has been designed in this thesis and tested in several numerical examples (chapter 10) as the Test-Case proposed by the ASCE Task Committee on Canal Automation Algorithms (chapter 11). In that sense, we propose a centralized control performance to manage the canal control. In addition to these two main contributions, many other smaller developments, minor results and practical recommendations for irrigation canal automation are presented throughout this thesis.Aquesta tesi té com a objectiu principal desenvolupar un control predictiu per a canals de reg i d'aquesta manera fer una aportació a la gestió dels recursos hídrics. L'aigua és un bé escàs i necessari per a la vida. És un recurs que fem un ús habitual d'ell, per consum propi, a la industria, com a font d'energia, a la agricultura.... .Un recurs tan preuat en zones amb escassetat per sequeres prologades constitueix un problema important, ja que afecta al desenvolupament de la zona. Concretament al sector de la agricultura pot provocar una davallada dels cultius i la incapacitat de cobrir les necessitats de la zona. L'agricultura és una part important de la cadena alimentària i els recursos hídrics per a l'agricultura són imprescindibles. Un greu problema a la agricultura son els baixos rendiments dels cultius moltes vegades relacionats amb sistemes de transport d'aigua poc eficients. La gestió dels recursos hídrics ha de ser optimitzada per obtenir rendiments competitius, ja que l'objectiu d'un gestor d'aigua és lliurar l'aigua de reg amb precisió i eficiència. Per millorar l'eficiència dels sistemes de transport d'aigua és necessari invertir en l'automatització dels canals de reg. Per complir aquests objectius, es defineix un esquema general de control al capítol 5, que divideix la gestió del control de canal en diferents blocs. La gestió d'un canal de reg s'inicia amb la programació de les demandes hídriques dels agricultors tenint en compte les necessitats dels diferents cultius durant un cicle de reg. Amb aquesta informació el watermaster tindria que establir les trajectòries de comporta o les accions de control per lliurar les demanades hídriques requerides als diferents punts del canal. En un cas ideal, el sistema seria controlat però a la realitat alguns factors externs podrien desviar l'estat desitjat del real, com per exemple extraccions de cabal desconeguts. En aquest cas, caldria introduir en el nostre diagrama general de control, altres algoritmes que podrien ajudar al WaterMaster a restablir l'estat desitjat. Aquests algoritmes, desenvolupats i testejats per nosaltres, són els algoritmes CSI i GoRoSoBo. CSI defineix una poderosa eina en la gestió d'un canal. El Watermaster estableix les posicions de les comportes i fixa el nivell d'aigua desitjat per complir amb les demandes hídriques programades en diferent punts del canal. En aquest sentit, quan algú introdueix una pertorbació altera el nivells de l'aigua al llarg del canal modificant els lliuraments programats inicialment de tal manera que no es podrien complir. En aquest cas, les mesures dels nivells d'aigua en diferents punts de control podrien ser enviats al algoritme CSI que tenint en compte aquest informació, les trajectòries de comporta i les demandes previstes calcularia el caudal real extret per les estructures de control i l'estat hidrodinàmic del canal, és a dir, el nivell de l'aigua i la velocitat en totes les seccions del canal. Aquesta tasca es duu a terme mitjançant l'algorisme CSI que ha estat dissenyat en aquesta tesi i provat en nombrosos exemples numèrics (capítol 7) i experimentalment en un canal de laboratori de la Universitat Politècnica de Catalunya (capítol 8). L'altre algorisme (GoRoSoBo) és l'eina essencial en la gestió d'un canal, és a dir, un algoritme de control que opera en temps real. GoRoSoBo (Gómez, Rodellar, Soler, Bonet) és un algorisme de control de retroalimentació (feedback) que calcula les trajectòries de comporta òptimes per un horitzó de predicció tenint en compte l'estat hidrodinàmic del canal en el moment actual i els caudals reals d'extracció obtinguts per CSI, així com les demandes programades i les trajectòries de comporta anteriors. GoRoSoBo ha estat dissenyat en aquesta tesi i provat en diversos exemples numèrics (capítol 10), així com als casos de prova proposats pel ASCE (Clemmens et a., 1998) (capítol 11) amb resultats excel·lent

Instrumentation, model identification and control of an experimental irrigation canal

This thesis aims to develop control algorithms for irrigation canals in an experimental framework.These water transport systems are difficult to manage and present low efficiencies in practice. As a result, an important percentage of water is lost, maintenance costs increase and water users follow a rigid irrigation schedule.All these problems can be reduced by automating the operation of irrigation canals.In order to fulfil the objectives, a laboratory canal, called Canal PAC-UPC, was equipped and instrumented in parallel with the development of this thesis. In general, the methods and solutions proposed herein were extensively tested in this canal.In a broader context, three main contributions in different irrigation canal control areas are presented.Focusing on gate-discharge measurements, many submerged-discharge calculation methods are tested and compared using Canal PAC-UPC measurement data. It has been found that most of them present errors around ±10%, but there are notable exceptions. Specifically, using classical formulas with a constant 0.611 contraction value give very good results (errorWith respect to irrigation canal modeling, a detailed procedure to obtain data-driven linear irrigation canal models is successfully developed. These models do not use physical parameters of the system, but are constructed from measurement data. In this case, these models are thought to be used in irrigation canal control issues like controller tuning, internal controller model in predictive controllers or simply as fast and simple simulation platforms. Much effort is employed in obtaining an adequate model structure from the linearized Saint-Venant equations, yielding to a mathematical procedure that verifies the existence of an integrator pole in any type of canal working under any hydraulic condition. Time-domain and frequency-domain results demonstrate the accuracy of the resulting models approximating a canal working around a particular operation condition both in simulation and experiment.Regarding to irrigation canal control, two research lines are exploited. First, a new water level control scheme is proposed as an alternative between decentralized and centralized control. It is called Semi-decentralized scheme and aims to resemble the centralized control performance while maintaining an almost decentralized structure. Second, different water level control schemes based on PI control and Predictive control are studied and compared. The simulation and laboratory results show that the response and performance of this new strategy against offtake discharge changes, are almost identical to the ones of the centralized control, outperforming the other tested schemes based on PI control and on Predictive control. In addition, it is verified that schemes based on Predictive control with good controller models can counteract offtake discharge variations with less level deviations and in almost half the time than PI-based schemes.In addition to these three main contributions, many other smaller developments, minor results and practical recommendations for irrigation canal automation are presented throughout this thesis

SCADA and related technologies

Presented at SCADA and related technologies for irrigation district modernization, II: a USCID water management conference held on June 6-9, 2007 in Denver, Colorado.Northern Water (Northern Colorado Water Conservancy District) conducted field demonstrations and comparisons of flow monitoring equipment at 18 canal and ditch sites in the lower South Platter River Basin during the 2006 irrigation season. Equipment included data loggers from 8 different manufacturers, 16 different models of water level sensors from 12 manufacturers, and 4 different types of telemetry from 7 manufacturers. The data loggers that were demonstrated included four models of single-sensor with integrated data logger, four models of programmable multi-sensor data logger, and one model of basic, low-cost data logger without telemetry. Relative equipment costs for each data logger system are summarized in Table 6. The water level sensors tested included submersible pressure transducers, optical shaft encoders, ultrasonic distance sensors, bubbler level sensor, float and pulley with potentiometer, buoyancy sensor, and a laser distance sensor. Bench checks of sensor calibrations were accomplished by Northern Water staff before field installation, and again at the end of the irrigation season. Observed sensor accuracy was compared to that expected from manufacturer specifications. The telemetry systems tested in the field included license-free spread-spectrum radios from four manufacturers, licensed radio modems in the 450 MHz range, satellite radio modems to a web server, and cdma modems with static IP addresses. Increased mast height and high gain directional antenna improved radio telemetry as expected. Additionally, operational files were utilized to document telemetry performance when available. The purpose and intent of the equipment demonstration and comparison was not to identify a single best data logger, sensor, and/or telemetry system. Each has different features and strengths, as well as varying costs. For each specific flow monitoring application, different equipment may be preferred or better suited than other equipment. However, the 2006 demonstration and comparison should provide a reference point for those seeking to become more knowledgeable in equipment selection while avoiding unpleasant surprises

Coalitional model predictive control for systems of systems

An aspect so far rarely contemplated in distributed control problems is the explicit consideration of individual (local) interests of the components of a complex system. Indeed, the focus of the majority of the literature about distributed control has been the overall system performance. While on one hand this permitted to address fundamental properties of centralized control, such as system-wide optimality and stability, one the other hand it implied assuming unrestricted cooperation across local controllers. However, when dealing with multi-agent systems with a strong heterogeneous character, cooperation between the agents cannot be taken for granted (due to, for example, logistics, market competition), and selfish interests may not be neglected. Another critical point that must be kept into consideration is the diversity characterizing systems of systems (SoS), yielding very complex interactions between the agents involved (one example of such system is the smart grid). In order to tackle such inherent aspects of SoS, the research presented in this thesis has been concerned with the development of a novel framework, the coalitional control, that extends the scope of advanced control methods (in particular MPC) by drawing concepts from cooperative game theory that are suited for the inherent heterogeneity of SoS, providing as well an economical interpretation useful to explicitly take into account local selfish interests. Thus, coalitional control aims at governing the association/dissociation dynamics of the agents controlling the system, according to the expected benefits of their possible cooperation. From a control theoretical perspective, this framework is founded on the theory of switched systems and variable structure/topology networked systems, topics that are recently experiencing a renewed interest within the community. The main concepts and challenges in coalitional control, and the links with cooperative network game theory are presented in this document, tracing a path from model partitioning to the control schemes whose principles delineate the idea of coalitional control. This thesis focuses on two basic architectures: (i) a hierarchically supervised evolution of the coalitional structure, and (ii) a protocol for autonomous negotiation between the agents, with specific mechanisms for benefit redistribution, leading to the emergence of cooperating clusters.Premio Extraordinario de Doctorado U

USCID 14th technical conference

Presented at Contemporary challenges for irrigation and drainage: proceedings from the USCID 14th technical conference on irrigation, drainage and flood control held on June 3-6, 1998 in Phoenix, Arizona.Metering of farm water deliveries in the Imperial Irrigation District has always been a costly and difficult procedure. Due to existing structural and environmental conditions, many of the traditional methods of metering deliveries had in the past proved cumbersome or unsuccessful. With funding provided by the IID/MWD Water Conservation Program, a method for utilizing ultrasonic transducers for metering farm water deliveries under orifice flow conditions has been developed. These on-farm water level sensors were designed to be portable, environmentally rugged, solar powered, simple to operate and maintain, and visually unobtrusive to minimize vandalism. This paper describes the construction of the on-farm water level sensors and their function as a useful tool in providing rapid and accurate irrigation evaluations to farmers

Water Supply Infrastructure Modeling and Control under Extreme Drought and/or Limited Power Availability

abstract: The phrase water-energy nexus is commonly used to describe the inherent and critical interdependencies between the electric power system and the water supply systems (WSS). The key interdependencies between the two systems are the power plant’s requirement of water for the cooling cycle and the water system’s need of electricity for pumping for water supply. While previous work has considered the dependency of WSS on the electrical power, this work incorporates into an optimization-simulation framework, consideration of the impact of short and long-term limited availability of water and/or electrical energy. This research focuses on the water supply system (WSS) facet of the multi-faceted optimization and control mechanism developed for an integrated water – energy nexus system under U.S. National Science Foundation (NSF) project 029013-0010 CRISP Type 2 – Resilient cyber-enabled electric energy and water infrastructures modeling and control under extreme mega drought scenarios. A water supply system (WSS) conveys water from sources (such as lakes, rivers, dams etc.) to the treatment plants and then to users via the water distribution systems (WDS) and/or water supply canal systems (WSCS). Optimization-simulation methodologies are developed for the real-time operation of water supply systems (WSS) under critical conditions of limited electrical energy and/or water availability due to emergencies such as extreme drought conditions, electric grid failure, and other severe conditions including natural and manmade disasters. The coupling between WSS and the power system was done through alternatively exchanging data between the power system and WSS simulations via a program control overlay developed in python. A new methodology for WDS infrastructural-operational resilience (IOR) computation was developed as a part of this research to assess the real-time performance of the WDS under emergency conditions. The methodology combines operational resilience and component level infrastructural robustness to provide a comprehensive performance assessment tool. The optimization-simulation and resilience computation methodologies developed were tested for both hypothetical and real example WDS and WSCS, with results depicting improved resilience for operations of the WSS under normal and emergency conditions.Dissertation/ThesisDoctoral Dissertation Civil, Environmental and Sustainable Engineering 201

SCADA and related technologies for irrigation district modernization

Presented at SCADA and related technologies for irrigation district modernization: a USCID water management conference on October 26-29, 2005 in Vancouver, Washington.Includes bibliographical references.Overview of Supervisory Control and Data Acquisition (SCADA) -- Total Channel Control™ - The value of automation in irrigation distribution systems -- Design and implementation of an irrigation canal SCADA -- All American Canal Monitoring Project -- Taking closed piping flowmeters to the next level - new technologies support trends in data logging and SCADA systems -- Real-time model-based dam automation: a case study of the Piute Dam -- Effective implementation of algorithm theory into PLCs -- Optimal fuzzy control for canal control structures -- SCADA over Zigbee™ -- Synchronous radio modem technology for affordable irrigation SCADA systems -- A suggested criteria for the selection of RTUs and sensors -- Irrigation canals in Spain: the integral process of modernization -- Ten years of SCADA data quality control and utilization for system management and planning modernization -- Moderately priced SCADA implementation -- Increasing peak power generation using SCADA and automation: a case study of the Kaweah River Power Authority -- Eastern Irrigation District canal automation and Supervisory Control and Data Acquisition (SCADA) -- Case study on design and construction of a regulating reservoir pumping station -- Saving water with Total Channel Control® in the Macalister Irrigation District, Australia -- Leveraging SCADA to modernize operations in the Klamath Irrigation Project -- A 2005 update on the installation of a VFD/SCADA system at Sutter Mutual Water Company -- Truckee Carson Irrigation District Turnout Water Measurement Program -- The myth of a "Turnkey" SCADA system and other lessons learned -- Canal modernization in Central California Irrigation District - case study -- Remote monitoring and operation at the Colorado River Irrigation District -- Web-based GIS decision support system for irrigation districts -- Using RiverWare as a real time river systems management tool -- Submerged venturi flume -- Ochoco Irrigation District telemetry case study -- Uinta Basin Replacement Project: a SCADA case study in managing multiple interests and adapting to loss of storage -- Training SCADA operators with real-time simulation -- Demonstration of gate control with SCADA system in Lower Rio Grande Valley, in Texas -- Incorporating sharp-crested weirs into irrigation SCADA systems