Response of ASCE Task Committee Test Cases to Open-Loop Control Measures

Abstract

Automated open- and closed-loop control systems can enhance the performance of irrigation delivery systems. This paper examines the response of the canal test cases developed by the ASCE task committee on canal automation algorithms to a particular anticipatory open-loop control technique, gate stroking. The performance of the ideal gate-stroking solution is compared with the performance of an approximate gate-stroking schedule that was generated by imposing practical constraints on the frequency and magnitude of the gate adjustments. Also analyzed were the performance of a nonanticipatory open-loop control scheme and the effect of model parameter uncertainties on the effectiveness of the control. For the test cases, the approximate gate-stroking schedules performed similarly to the ideal schedules. For two of the test cases, delivery performance was similar with and without anticipation, but was substantially different for the other two tests. The quality of the control degraded as a result of errors in model parameters, particularly in cases with incorrect check gate calibrations and submerged gate flows. Results point out the importance of combining open- and closed-loop control measures to improve the overall effectiveness of the control.