Roll Position Demand Autopilot Design using State Feedback and Reduced Order Observer (DGO)

– A Roll Position demand (as well as Roll Position Control) missile autopilot design methodology for a class of guided missile, based on state feedback, Ackermann pole-placement and reduced order Das & Ghosal observer (DGO), is proposed. The open loop unstable model of the roll control (or roll position demand) autopilot has been stabilized by using pole placement and state feedback. The non-minimum phase feature of rear controlled missile airframes is analyzed. Actuator dynamics has also been included in this design to make the overall system practically suitable for use. The overall responses of the Roll Control autopilot has been significantly improved over the frequency domain design approach where phase lag & phase lead compensator were used. Closed loop system poles are selected on the basis of desired time domain performance specifications. This set of roots not only to ensure the system damping, but also to make sure that the system can be fast. Reduced order Das & Ghosal (DGO) observer is implemented successfully in this design to estimate the Aileron angle and its rate. Finally a numerical example is considered and the simulated results are discussed in details. The date set has been chosen here for which largest rolling moment would occur (at Mach No = 4) due to unequal incidence in pitch and yaw. Keywords–– Roll Position & Roll Rate Control Autopilot, Ailerons-Rollerons, Roll Gyro, Fin Servo Actuator, Aerodynamic control, Luenberger Observer, Das & Ghosal Observer, Generalized Matrix Inverse and Ackermann.