The Central Arizona Project (CAP) has been supplying Colorado River water to Central Arizona for roughly 25 years. The CAP canal is operated remotely with a supervisory control and data acquisition (SCADA) system. Gate-position changes are made either manually or through the use of automatic controls with a controlled-volume approach. In this paper, the writers examine the potential application to the CAP canal of water-level difference control, a new feedback canal-control method. The main objective of this method is to keep the downstream water-level errors in equal pools. The control model is a multiple input and multiple output (MIMO) system, and the controller is solved as a linear quadratic regulator (LQR). A feed-forward routine called volume compensation was also used to route the flow changes. Simulation results show that this method is stable and can deal with different kinds of changes relatively quickly. For small changes, the water-level difference controller can operate well even without rou...

A new Proportional-Integral (PI) tuning method based on Linear Matrix Inequalities (LMIs) is presented. In particular, an LMI-based optimal control problem is solved to obtain a sparse feedback that provides the PI tuning. The ASCE Test Canal 1 is used as a case study. Using a linearised model of the canal, different tunings for the design of the PI controller are developed and tested using the software Sobek. Furthermore, the proposed method is also compared with other tunings proposed for the same canal available in the literature. Our results show that the proposed method reduces by half the maximum errors with respect to other assessed alternatives and minimizes undesired mutual interactions between canal pools. Also, our method improves the optimality degree of the PI tuning by 30%. Therefore, it is concluded that the LMI based PI controllers lead to satisfactory performance in regulating water levels and canal flows/structure outflows, outperforming other tested alternatives, thus becoming a useful tool for irrigation canal control.

Proportional-integral (PI) control, as one of the most popular classic control methods, has been applied widely to the real-world practice of canal automatic control. The performance of a PI controller largely depends on two key parameters, namely the proportional constant $K_p$ and the integrational time constant $T_i$ . Rather than tuning these parameters empirically or in terms of the canal morphology, this study proposes a linear quadratic regulator (LQR) to determine their optimal values. The proposed LQR utilizes an integrator delay model to represent the hydrodynamics of open canals in order to minimize changes in water levels and flow rates. In addition, the weights for the optimization objective in the LQR are determined by an optimized quadratic performance indicators estimate (OQPIE), using the precalculated nondimensional integrated square of error and nondimensional integrated absolute discharge change as well as inherent designed parameters, which potentially impact the stability of system states. In this way, the LQR can fit various canal automation applications, especially for low-gradient canals. The optimal PI controller was tested on two different-scaled canals. Results showed that the objective was met satisfactorily, and stability can be reached in hours.

In order to automatically and safely control long distance water delivery projects in winter, there is a need for a reasonable and feasible transition mode to avoid the emergence of ice jam. Based on open canal hydraulics, a mathematical model of canal system operated by constant downstream depth method is developed. The principle of combining feed-forward control of discharges with feedback control of water level is adopted for operation of check gates and a simulation model of multiple serial canal sections is established. Also, reasonable parameters of proportional-integral (PI) controller and logical dead band are obtained by trial and optimizing. The model is applied to simulate the operation process of the canal sections part of the main canal of the middle route of the South-to-North Water Transfer Project in China. Flow velocities are reduced to less than 0.4 m/s by decreasing discharges of canal pools and turnouts in terms of 3 days' cold current forecast in advance. As a result, discharge in canal was reduced from 70% designed capacity to less than 30%, which is a big challenge for the controller. This paper tests the suggested transition mode from open-channel water transfer state to a low flow ice-forming state at the MATLAB platform, and the results show that this model can achieve the expected goals.