Robust Control for Irrigation Canals (original) (raw)
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Mathematical model for robust control of an irrigation main canal pool
Environmental Modelling & Software, 2014
This paper describes the formulation and development of a mathematical model for high-performance robust controller design techniques, based on a complete identification for control procedure, of an irrigation main canal pool (true plant), which is characterized by the exhibition of large variations in its dynamic parameters when the discharge regime changes in the operating range [Qmin, Qmax]. Real-time field data has been used. Four basic steps of the proposed procedure have been defined in which all the stages, from the design of the experiments to the model validation, are considered. This procedure not only delivers a nominal model of the true plant, but also a reliable estimate of its model uncertainty region bounded by the true plant models under minimum and maximum operating discharge regimes (limit operating models). The model uncertainty set, defined by the nominal model and its uncertainty region, is characterized by its being as tight as possible to the true irrigation main canal pool. The obtained results are very promising since this kind of models facilitates the design of robust controllers, which allow improving the operability of irrigation main canal pools and also substantially reduce water losses.
Robust controller for an open irrigation canal prototype
Indonesian Journal of Electrical Engineering and Computer Science
A Management and control of irrigation canals is a very important task whether for irrigation of agricultural land, to provide clean water, or to avoid floods. Irrigation canals are sometimes subject to intense variations due to climate change and inclement weather. For this reasons, a robust controller that allows dealing with large variation in operating conditions is proposed to control the water level of a multi-pool open irrigation canal prototype. The main objective of this study is to regulate the downstream level of each canal's pool at a constant value even with inflow disturbances. The robust controller is designed and tested in simulation for different operating conditions. The results obtained show the good behavior and the effectiveness of the designed controller.
Control-Oriented Model of a Complex Irrigation Main Canal Pool
Proceedings of the 18th IFAC World Congress, 2011
A control-oriented model of a complex irrigation main canal pool (plant), which is characterized by the exhibition of large variations in their dynamic parameters when the discharge regime changes in the operating range [Q min , Q max ], has been developed using system identification for control procedure and also using real-time data. The control-oriented model is comprised by the nominal model of the true plant and for its uncertainty region bounded by the true plant models under low and high operating discharge regimes (limit operating models). The model is obtained from the use of both experimental data, which correspond to main operating discharge regimes of the true plant, and the Prediction Error framework. The results are very encouraging since control-oriented models facilitate the design of high-performance robust controllers, which allow the operability and efficiency of irrigation main canal pools to be increased and service to the users to be improved.
Modeling, control and field tests on an experimental irrigation canal
2002
Irrigation canals are complex hydraulic systems difficult to control. Many models and control strategies have already been developed using linear control theory. In the present study, a PI controller is developed and implemented in a brand new prototype canal and its features evaluated experimentally. The base model relies on the linearized Saint-Venant equations which is compared with a reservoir model to check its accuracy. This technique will prove its capability and versatility in tuning properly a controller for this kind of systems
Modelling and PI control of an irrigation canal
The main goal of this paper is to expose and validate a methodology to design efficient automatic controllers for irrigation canals, based on the Saint-Venant model. This model-based methodology enables to design controllers at the design stage (when the canal is not already built). The methodology is applied on an experimental canal located in Portugal. First the full nonlinear PDE model is calibrated, using a single steady-state experiment. The model is then linearized around a functioning point, in order to design linear PI controllers. Two classical control strategies are tested (local upstream control and distant downstream control) and compared on the canal. The experimental results shows the effectiveness of the method.
Irrigation and Drainage, 2015
The performance and operation of irrigation networks can be improved using canal automation. This process requires the application of control systems. At the same time, the PI controller has been employed in different areas of the world. However, its adjustment for the different geometric and hydraulic conditions of canals is still considered a major problem for design. The design parameters of a canal such as bottom slope, roughness coefficient and side slope are among the determining factors of water flow dynamic behaviour. In this study, a distant downstream proportional integral feedback control with decouplers is designed for a base canal. By changing the value of design parameters in this canal, their effects on water flow behaviour and controller tuning were investigated. Canal characteristics were determined through a system identification process, and were also used to tune the controller. To simulate the control algorithms and evaluate their performance, a link of the SOBEK model and MATLAB software were used. To evaluate the performance of a well-tuned controller during a given operation period, the maximum absolute error, integral of absolute magnitude of error and steady-state error indicators were used. Generally, the result showed the bottom slope to have the most effect on water flow behaviour and tuning of the control algorithm. The effect of the roughness coefficient on the control algorithm and its performance is also more noticeable than the side slope.
Predictive control of irrigation canals – robust design and real-time implementation
Water Resources Management, 2016
Predictive control is one of the most commonly used control methods in a variety of application areas, including hydraulic processes such as water distribution canals for irrigation. This article presents the design and application of predictive control for the water discharge entering into an irrigation canal located in Spain. First, a discrete time linear model of the process is described and its parameters are experimentally identified. The model is well validated within the usual canal operating range and is used to formulate a predictive control law with an incremental formulation. Finally, experimental and simulation results are presented in which predictive control has shown better performance than a well-tuned proportional, integral and derivative controller to automatically manage demanded water discharges.
First Experimental Results of Nonlinear Control in Irrigation Canals
IFAC Proceedings Volumes, 2004
This paper presents various real-time results obtained on an experimental canal reach. with two types of nonlinear controllers. The controllers have been designed on the basis of a simple collocation model previously proposed for water dynamics in canal reaches. They only use water level measurements and are based on a non linear observer for water flow rate estimation. Stability conditions for the corresponding closed-loop schemes result from previous studies. and successful experimental results show that such conditions can indeed be achieved in practice.
Water Delivery Quality and Automatic Control Modes in Irrigation Canals. A Case Study
2004
Regarding canal management modernization, water savings and water delivery quality, the study presents two automatic canal control approaches of the PI (Proportional and Integral) type: the distant and the local downstream control modes. The two PI controllers are defined, tuned and tested using an hydraulic unsteady flow simulation model, particularly suitable for canal control studies. The PI control parameters are tuned using optimization tools. The simulations are done for a Portuguese prototype canal and the PI controllers are analyzed and compared considering a demand-oriented-canal operation. The paper presents and analyzes the two control modes answers for five different offtake types – gate controlled weir, gate controlled orifice, weir with or without adjustable height and automatic flow adjustable offtake. The simulation results are compared using water volumes performance indicators (considering the demanded, supplied and the effectives water volumes) and a time indicato...