The paper reviews several methods to convert discharge into gate opening. A control algorithm for one or several reaches of an irrigation canal sometimes uses a discharge as the control action variable even though the device to be manipulated is a gate or a weir. In this case a slave controller has to convert the discharge into a gate opening or a sill elevation in case of a weir. This is usually done by inverting the static relation between discharge and gate opening. An improved method can be based on the characteristics theory to estimate the water levels deviations. However, both these methods underestimate the gate opening deviations required to deliver a desired discharge deviation, because water levels vary continuously along time when the gate is operated. The paper proposes a method to take account of this dynamic behavior of the pool-gate interaction by using a simple linear model for the pools dynamics, the IDZ model. The proposed method enables to better estimate the gate opening necessary to get a desired average discharge. The method is evaluated in simulation and on a gate of the Gignac Canal, located in the South of France. A dimensionless analysis of the problem is finally performed to evaluate the methods' applicability.
展开▼
