Copyright © IFAC System. Structure and Control Oaxaca. Mexico. USA. 8-10 December 2004 ElSEVIER IFAC PUBLICATIONS www.elsevier.comllocatelifac FIRST EXPERIMENTAL RESULTS OF NONLINEAR CONTROL IN IRRIGATION CANALS * Gildas • Didier Georges • Victor Ruiz-Carmona •• Ofelia Begovich ••• Carlos I van Aldana Lopez ••• • Laboratoire d'Alltomatiqlle de Grenoble ENSIEG BP 46 - 38402 Saint-Martin d'Heres, France {Gildas.Besancon,Didier.Georges}@inpg.fr •• Riego y Drenaje, IMTA. Paseo Cuauhllahllac 8532, Jiutepec, Mor. 62550, Mexico vrnruiz@tlaloc.imta.mx ••• Cillvestav, Glladalajara, Mexico. {obegovi,ialdana}@gdl . cinvestav.mx Abstract: 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. Copyright ©2004IFAC. Keywords: Open channel systems, water level regulation, feedback linearization, high gain observer, experimental results. I. INTRODUCTION Most of irrigation canals are currently operated man- ually. but improving the achieved performances re- quires closed-loop control. The water flow dynamics in open channel systems are classically described by a couple of nonlinear partial differential equations which are not easily usable for control purposes. Var- ious modelling approaches have been inspected for canal oriented control design. from black-box linear models to infinite dimensional non linear ones, includ- ing infinite dimensional linearized models. and finite dimensional nonlinear ones (see for instance (Balogun et al., 1988; Sawadogo et al .• 1995; Baume et al.. 1998; Ouarit et al .• 2(03) for linear approaches,(Coron et al .. 1999) for a nonlinear infinite dimensional result. ., This work has been supponed by the French-Mexican depan· men! of applied controllAFMAA. 469 (Malaterre et al .. 1998; Ruiz-carmona et at.. 1998) for surveys on control algorithms for canals, or (Georges et al., 2(02) and references therein for a more general overview). Among those works, it has been shown via simulations and analysis that a reduced order nonlinear model which can still fairly represent the system can be obtained by a so-called collocation method (Georges et al., 2000), and a nonlinear con- troller has already been proposed for such a model and tested in simulation (Dulhoste et al., 200 I; Dulhoste et al., 2004). The main purpose here is to comfort this previous study by experimental results obtained on the same basis. and using some refinements in the design. To our knowledge. these experimental results represent the first validation of a non linear control on a real canal reach .