2-DOF Observer Based Controller for Integral Process with Dead Time using PSO

This paper presents a design methodology for two degrees of freedom (2-DOF) observer based controller for the integral processes with dead time. The 2-DOF controller structure facilitates independent design for feedback properties and set point tracking. The feedback controller aims to achieve stability, robustness and disturbance attenuation whereas prefilter design produces satisfactory set point response. In the approach presented here, the feedback controller and prefilter designs are posed as optimization problems which are solved using particle swarm optimization (PSO). Feedback controller design is based on H∞ theory using objective function which is H∞ norm of the mixed sensitivity. Fixed structure polynomial controller is taken as feedforward controller. The parameters of the feedforward controller are designed by solving a model matching problem assuming a reference model. The objective function taken for that is Integral Square Error (ISE). Three design examples are worked out to show the efficiency of the design approach.