Real Time Implementation of Enhanced Nonlinear PID Controller for a Conical Tank Process

Abstract

Level is one of the most important parameter that has to be monitored and controlled in any process industry.  Conical tanks are widely used in many industries due to its shape which provides easy discharge of water when compared to other tanks. Moreover, liquid level control of a conical tank is still challenging for typical process control because of nonlinearities.  Since PID control is the workhorse of almost 90% of the industries, an Enhanced Nonlinear PID (EN-PID) controller is proposed which exhibits the improved performance than the conventional linear fixed-gain PID controller, by incorporating a sector-bounded nonlinear gain in cascade with a conventional PID control architecture. To achieve the high robustness against noise, two nonlinear tracking differentiators are proposed to select high-quality differential signal in the presence of measurement noise. The main advantages of the proposed EN-PID controller lie in its high robustness against noise and ease of implementation.   And in the proposed technique a EN-PID is designed and tuned using the Bee colony optimization (BCO) technique. The BCO algorithm is based on the model that is obtained from the communicative behavior of the honey bees. Simulation results performed on a conical tank level process are presented to demonstrate the performance of the developed EN-PID controller.