Comparative Study of Controllers for a Variable Area MIMO Interacting NonLinear System

Most of the industrial processes are basically Multi Input Multi Output (MIMO) system. In this paper a new combination of Spherical Conical Interacting Tank System (SCITS) which is a variable area nonlinear MIMO system is considered for study and various control algorithms based on Ziegler Nichol’s tuning method, Hagglund Astrom Robust tuning method, Fractional Order (FO) control and Passivity Based Control (PBC) are used and compared for the level control of spherical tank system and conical tank system connected with interaction. Transfer function matrix of the system is obtained experimentally from the open loop response of the system. The designed controllers are tested for servo and regulatory operations. The controllers are compared in terms of time domain specification and performance index criterion. From the analysis of the simulation results, it is seen that FO controller gives improved performance when compared to conventional Integer Order (IO) controller and overall Passivity Based Controller (PBCr) gives improved performance comparatively for spherical conical interacting MIMO system. [email protected] Keyword-Spherical-Conical interacting system, MIMO system, Fractional Order Control, Passivity Based Control, PI controller