CONSTRUCTION AND EVALUATION OF THE BIVAL AUTOMATIC CONTROL SYSTEM FOR IRRIGATION CANALS IN A LABORATORY FLUME

摘要

Automation of structures is one of the main options for improving operations to increase the flexibility of irrigation canals. For local development of automatic system technology and its application, the facilities have to be constructed, and after testing in the laboratory, the system can be introduced for practical application in irrigation canals. One of the important automatic downstream control systems is the Bival control system. In this research, the Bival downstream control system is constructed and tested. Experiments of the automatic control system were performed in a rectangular laboratory flume with dimensions of 0.3 x 0.45 x 10 m. The hardware of the system includes depth and gate opening sensors, motors, slide gates, electronic boards and a computer. The system's software is the Bival automatic control system, which was developed and connected with equipment using LABVIEW software. To study the performance of the developed system, different scenarios of gradual and sudden downstream flow variations were tested. Maximum absolute error (MAE), integral of absolute magnitude of error (IAE), system response time (SRT) and percentage of volume variation (PVV) indicators, in addition to depth variations in time, were used to assess system performance. For a case of sudden flow decrease, the indicators value are obtained as 0.22, 0.06, 1.51 min, and 0.62, respectively, which are acceptable and indicate a smooth action of the control system. The results showed that the performance of the developed Bival automatic control system is appropriate, and it could be introduced to be applied in irrigation canals. Copyright (C) 2011 John Wiley & Sons, Ltd.