Modeling and regulation of irrigation canals: existing applications and ongoing researches (original) (raw)
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Irrigation canal models for automatic control purposes
2011
volumes during normal canal operation. In order to develop control algorithms for irrigation canals there is a need for simple linear models to be used in the algorithms. The following simple linear models are approximating the canal in order to give a base to develop control algorithms. The PAC-UPC laboratory canal (Prueba de Algoritmos de Control - Universitat Politecnica de Catalunya) is modelled (input and output discharge) using the following three models: Muskingum, Hayami and Integrator Delay Zero (IDZ) and the results are compared to measurements. All three models are able to describe the irrigation canal in an acceptable way. However, only the IDZ model can capture all the important characteristics. These tested models can be applied to represent real canals for control purposes where it is especially important to obtain good models without extensive measurements. Test campaigns are developped now in cooperation with the CHE (Confederacion Hidrografica del Ebro) in order to...
A New Nonlinear Control Methodology for Irrigation Canals Based on a Delayed Input Model
2008
This paper is devoted to nonlinear feedback design for irrigation canals. Such systems are classically described by Saint-Venant nonlinear partial differential equations. Here instead, an ordinary differential equation model (still nonlinear) with a state-dependent input delay is used, on the basis of a model previously proposed in Litrico et al [2003]. The control design approach is based on a state prediction computation and the state predictor is constructed from a dynamic inversion in the same spirit as in Georges et al [2007]. The proposed methodology is analyzed and tested in simulation, first on the basis of the control model, and then using some "more accurate" model.
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 of irrigation channel dynamics for controller design
SMC'98 Conference Proceedings. 1998 IEEE International Conference on Systems, Man, and Cybernetics (Cat. No.98CH36218), 1998
Irrigation canals are complex hydraulic systems difficult to control. Design methods have been developed using linear control theory. To use this tool, a linear model of the dynamic IS needed.This paper presents a simple model for canal reach dynamics. A reach transfer matrix is obtained by linearisation of Samt Venant equations near a steady flow regime.The accuracy of this transfer matrix is evaluated, in frequency and time domam.
Simplified Modeling of a Laboratory Irrigation Canal
— Modeling an irrigation canal is a crucial task in order to apply different kinds of control algorithms. In this paper three different models applied to a laboratory irrigation canal are compared. All of these models are calculated from the hydraulic characteristics of the canal and tested afterwards. In order to compare the performance of the models for control purposes, the implementation of simple controllers (PI controllers) for each model is carried out on the experimental platform " Canal PAC-UPC " .
Environmental Modelling & Software, 2014
Irrigation canals are open-flow water hydraulic systems, whose objective is mainly to convey water from its source down to its final users. They are large distributed systems characterized by non-linearity and dynamic behavior that depends on the operating point. Moreover, in canals with multiple reaches dynamic behavior is highly affected by the coupling among them. The physical model for those systems leads to a distributed-parameter model whose description usually requires partial differential equations (PDEs). However, the solution and parameter estimation of those PDE equations can only be obtained numerically and imply quite time-consuming computations that make them not suitable for real-time control purposes. Alternatively, in this paper, it will be shown that open-flow canal systems can be suitably represented for control purposes by using linear parameter-varying (LPV) models. The advantage of this approach compared to the use of PDE equation is that allows simpler models which are suitable for control design and whose parameters can be easily identified from input-output data by means of classical identification techniques. In this paper, the well known control-oriented, model named integral delay zero (IDZ), that is able to represent the canal dynamics around a given operating point by means of a linear time-invariant (LTI) model is extended to multiple operating points by means of an LPV model. The derivation of this LPV model for single-reach open-flow canal systems as well as its extension to multiple-reach open-flow canals is proposed. In particular, the proposed methodology allows deriving the model structure and estimating model parameters using data by means of identification techniques. Thus, a gray-box control model is obtained whose validation is carried out using single-pool and two-pool test canals obtaining satisfactory results.
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.
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.
Multivariable predictive control of irrigation canals. Design and evaluation on a 2-pool model
Proceedings of the International Workshop …, 1997
This paper presents the formulation of a multivariable controller for centralized control of canals based on the methodology of predictive control. The formulation relies on a linear state space model derived from Saint-Venant's equations discretized through the Preissmann implicit scheme. Predictive control uses this model to compute the control action that verifies a performance criterion defined over a finite prediction interval. The controller is combined with a Kalman filter to reconstruct the state variables and the unknown perturbations from a reduced number of measured variables, which are water levels at the upstream and downstream end of each pool. The control system is numerically tested on a 2-pool canal using a full non-linear simulation package (SIC).