Synthesis of robust PID controller for controlling a single input single output system using quantitativefeedback theory technique

In this paper, the modeling and control of a rotary missile that uses theproportional navigation law is proposed, applying the quantitative feedback theory (qft)technique. the dynamics of a missile are highly uncertain; thus, application of robustcontrol methods for high precise control of missiles is inevitable. in the modeling section,a new coordinate system has been introduced, which simplies analysis of rotary missiledynamics equations. in the controlling part, application of the qft method leads to thedesign of a robust pid controller for the highly uncertain dynamics of a missile. sincemissile dynamics have multivariable nonlinear transfer functions, in order to apply theqft technique, these functions are converted to a family of linear time invariant processeswith uncertainty. next, in the loop shaping phase, an optimal robust pid controller for thelinear process is designed. lastly, analysis of the design procedure shows that the robustpid controller is superior to the commonly used pid scheme and multiple sliding surfaceschemes, in terms of both tracking accuracy and robustness.