Fractional order PI controller for a conical tank process using different tuning methods

In industries nonlinear processes elements like conical tank or spherical tank is used for storage or processing of liquids. In this paper conical tank is used for analysis. Mathematically conical tank is a nonlinear due to its shape. The volume changes at every instant due to change in radius. In this paper fractional PI controller is used to maintain the liquid level of the tank at desired level. The performance of fractional order controller is compared with conventional controller for various tuning methods like Zeigler Nichols, Cohen-coon, CHR and Kappa-Tau.