Effect of Design Parameters of an Irrigation Canal on Tuning of Coefficients and Performance of a PI Controller

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.