Performance comparison between IOPID and FOPID controllers in an industrial flow pilot plant

Abstract This paper presents a performance comparison between Integer Order PID IOPID and Fractional Order PID FOPID controllers in an industrial pilot plant. Most processes use the IOPID to control process variables (PV) and due to its robustness and ease of implementation, it has been applied in the industry for many years. This controller has three parameters to tune: Proportional Gain KC, Integral Gain (KI) or Integral Time (TI) and Derivative Gain (KD) or Derivative Time (TD). But for FOPID, two more parameters are used to tune, called fractional factors λ and µ, belonging to the terms of the Integrative KI and Derivative KD gains, respectively. An interesting fact is that for over twenty years of exploitation of fractional drivers, they brought improvements in relation to IOPID, both in the regulatory and in the servo mode, steady state error (ess) practically null and robustness to the changes of process conditions. For tuning the Fractional PI controller (FOPI) the Bhaskaran method was used and for the FOPID the Fractional-order Modeling and Control (FOMCON) toolbox of MATLAB was applied. These results were verified in the tests carried out at the Flow Pilot Plant of the Industrial Control Processes Laboratory (ICPL). The FOPID presented in this paper, applied to a real industrial plant is pioneering and innovative.