Digital Feedback Control System for Canals

摘要

A digital feedback control system for canals is developed based on a numerical solution to the characteristic form of the Saint Venant equations for unsteady open channel flow. The canal systems composed of reaches separated by moveable radial check gate structures carry water that may be diverted for municipal, industrial and irrigation uses. The turnout diversions occur at the downstream ends of canal system reaches where the depth of flow is maximum. The primary task of the control system is to match flow of water in the canal system to the changes in turnout diversion demand for water. Depth responses at the downstream ends of canal system reaches are used as boundary conditions to determine the magnitude of the turnout diversion. The time-varying downstream depth is used in the C+ characteristic and gate discharge equations to predict the magnitude of the turnout diversion almost as soon as these occur. The new upstream gate opening is computed and implemented in order to return the canal system to a new steady state. A laboratory study is conducted to evaluate the performance of the control system.