Synthesisof Robust PID Controller for Controlling a Single Input Single Output System Using Quantitative Feedback Theory Technique

In this paper, modeling and control of a rotary missile which uses the proportional navigation law is purposed, applying Quantitative Feedback Theory (QFT) technique. Dynamics of missile are highly uncertain; thus application of robust control methods for high precise control of missiles is inevitable. In the modeling section, a new coordinate system has been introduced which simplifies the analysis of rotary missile’s dynamics equations. In the controlling part,applicationofQFTmethod leads to the design of robust PID controller for highly uncertain dynamics of missile. Since the missile’s dynamics have multivariable nonlinear transfer functions, in order to apply QFT technique, these functions are converted to a family of linear time invariant processes with uncertainty. Next, in the loop shaping phase, an optimal robust PID controller for thelinear process is designed. Lastly, analysis of design procedure shows that robust PID controller is superior to the commonly used PID scheme and multiple sliding surface schemes in terms of both tracking accuracy and robustness.