IMC based Fractional order PID controller

This article presents the design of Internal Model Controller (IMC) based Fractional Order Two-Degrees-of-Freedom controller with the desired bandwidth specification and the robustness of the designed controller is briefly analyzed. For the conventional IMC based PID controller, One-Degree of Freedom is sufficient to meet the desired bandwidth specification for both Servo and regulatory performances. These features of the IMC based PID controller is combined with fractional order controller, as the fractional calculus has made a major impact in the control research community. It has been analytically and mathematically proved that One-Degree of Freedom IMC based fractional order controller tuned for the disturbance rejection will not meet the nominal specification for the set point tracking. To overcome this drawback, IMC based fractional order Two-Degree-of-Freedom controller is reported in this article.