Designing Fuzzy Polynomial Gain Scheduled Three-Loop Autopilot For The Pitch Channel Of A Flying Vehicle

This paper presents a gain scheduled autopilot for pitch channel of a flying vehicle. The selected method is based on polynomial fuzzy systems. The method does not involve linearization about operating point. First the polynomial fuzzy model of pitch channel of the flight body is derived. Next, using polynomial fuzzy system methodology the controller is design such that the outputs of the nonlinear plant drive to follow those of a stable reference model. Because of avoiding actuator saturation, some constraints derived that guarantees the amplitude of control signals be less than a specific threshold. It is considered that the controller has a known structure like three-loop autopilot. In other words the three-loop fuzzy polynomial autopilot is design to satisfy stability and performance of the closed loop system over a wide range of parameter variation. Stability and performance conditions derived in terms of sum of square will solve numerically via SOSTOOLS.