Assessment and Comparison oF Fuzzy Automatic Control System using Two Rule Base Applied oN Pivot Weirs

Using effective methods to provide optimal performance of irrigation networks is inevitable because
of limited water resources and poor performance of irrigation networks. Different algorithms are used
for automatic control of water level in irrigation canals with their own limitations. Fuzzy logic is
capable of resolving some of these limitations. Although fuzzy logic is successfully used in many
engineering applications, it has not been used for water level control in irrigation canals. In this study
fuzzy algorithm with two rule base is used for automatic water level control on pivot weir. Automatic
control system was constructed on laboratory scale, and its performance for the situation of high flow
variation was evaluated. One of the main components of the fuzzy controller is rule-base decision
making. In the experiments conducted in this study two types of rule-base decision making are applied
and the results are compared. The results show that in high flow variations (400%), maximum absolute
error (MAE) and cumulative absolute error (IAE) indices values are in the range of 6.9 to 9.2 and 0.79
to 1.17percentages respectively and variations are stabilized within less than 2 minutes. Using the
second type of rule-base, system, stability is improved and water level variations and number of
structure adjustment is decreased. The fuzzy automatic control system is suitable in controlling water
levels and its application for irrigation canal control is recommended.