Control system design for 3x3 processes based on effective transfer function and fractional order filter

Abstract

Designing of PI/PID controller with fractional order set point filter is proposed to achieve the improved performance of 3x3 processes. But the design of controller for such higher dimensional multivariable processes is too difficult task because of interaction involved between the process variables. So interaction must be taken into design consideration. In this method of design determines the interaction between the variables using RGA and RNGA methods and uses it in converting the multivariable processes into multiple single loops. The interaction problems between the loops are overcome by incorporating the decouplers in the control loops. Then, the Effective Transfer Function (ETF) has obtained to design PI/PID controller for each individual element as in single input processes. The fractional order filter is also added to improve the servo response of the processes. Hence, the proposed system improves the overall performance by minimizing the interaction effects due to set point variations. This method is also validate by using a case study.