A Fractional and Integer Order PID Controller for Nonlinear System: Two Non-interacting Conical Tank Process Case Study

The mathematical model for two non-interacting conical tank level (TNICTL) process is proposed. The control of TNICTL process is difficult due to the nonlinearity. Hence, the nonlinear process is linearised around proper operating points. Then, the fractional-order and integer order PID controller are designed and the control parameters are tuned using Genetic Algorithm (GA) and Ziegler-Nichols (ZN) tuning methods. Also, system component (leak) and actuator faults are introduced into TNICTL and validate the proposed controller tolerance capacity. The closed-loop controller performances are simulated and compared in terms of settling time, rise time and integral error criteria. It is found that fractional order PID controller has better servo and regulatory response than the integer order PID controller. The liquid inflow rates are optimally manipulated by the fractional-order PID controller to track the set point variation and to reject the faults effectively than integer order PID controller.