Analysis and Design of Missile Two Loop Autopilot

In this paper, a flight path rate demand two loop autopilot in pitch plane called lateral autopilot is considered where the steady state gain of the autopilot system is non-unity .The present work is an attempt to achieve a unity steady state gain of the autopilot system which generates a flight path rate output for a flight path rate command. For this, a PI controller is introduced in the reduced order model of autopilot system obtained through Routh Approximation method in order to eliminate the static error and to obtain a unity steady state gain of the two loop autopilot system . A model based PI design method based on plants parameter is used for the calculation of PI gain values. A numerical example has been considered and the simulation results are obtained through MATLAB software.