Fuzzy gain scheduling of PID controller implemented on real time level control

In this paper a fuzzy approach for controlling the level of liquid in a tank is demonstrated. The proposed method is implemented to level control of a real laboratories plant using real time toolbox in Simulink software and data acquisition card, considering saturation issue, and responded properly in the existence of exogenous noises and disturbances. Main idea is PID gain scheduling through fuzzy algorithm, which provides us with an adaptive control system. This plant is a single input-single output system with constant liquid in-flow, so an operating point is defined here by the in-flow rate. Any constant PID controller gains, calculated through Ziegler-Nichols, Internal Mode Control and other methods for using in a conventional PID controller with this plant, would be a function of liquid in-flow, as a parameter of plant. In fuzzy approach, however, these gains can adaptively change to not only provide the de-sired steady state response but also to reach that state very fast. Experimental results for proposed controller are reported to show the effectiveness of proposed method.