The control of multivariable interacting process is difficult because of the interaction effect between input output variables. In the proposed work, an attempt is made to design a Multivariable Centralized Fractional Order PID (MCFOPID) controller with the use of evolutionary optimization techniques. The Bat Optimization Algorithm (BOA) and Harmony Search algorithm (HS), the evolutionary optimization techniques are used for the tuning of the controller parameters. As the process is a Two-Input-Two-Output process, four FOPID controllers are required for the control of the two interacting conical tank process. Altogether 20 controller parameters need to be tuned. In a single run, all the 20 parameters are founding considering the interaction effect minimizing Integral Time Absolute Error (ITAE). The BOA, HS based MCFOPID controller is validated under tracking and disturbance rejection for minimum ITAE.
Lakshmanaprabu, S. K., & Sabura Banu, U. (2016). Optimal tuning of multivariable centralized fractional order PID controller using bat optimization and harmony search algorithms for two interacting conical tank process. Studies in Computational Intelligence, 650, 215–235. https://doi.org/10.1007/978-3-319-33386-1_11