A Structured Optimal Controller for Irrigation Networks

TL;DR

This paper develops a structured optimal LQ controller for irrigation networks, demonstrating its effectiveness in maintaining water levels and outperforming traditional P controllers through simulation comparisons.

Contribution

It introduces a structured LQ controller designed with a first-order canal model, enabling distributed implementation and improved performance over P controllers.

Findings

Structured LQ controller outperforms P controller in simulations.

Controller designed with first-order approximation performs close to third-order optimal.

Demonstrates the feasibility of distributed control in irrigation networks.

Abstract

In this paper, we apply an optimal LQ controller, which has an inherent structure that allows for a distributed implementation, to an irrigation network. The network consists of a water reservoir and connected water canals. The goal is to keep the levels close to the set-points when farmers take out water. The LQ controller is designed using a first-order approximation of the canal dynamics, while the simulation model used for evaluation uses third-order canal dynamics. The performance is compared to a P controller and an LQ controller designed using the third-order canal dynamics. The structured controller outperforms the P controller and is close to the theoretical optimum given by the third-order LQ controller for disturbance rejection.