19. Linear Parameter-Varying Control for the X-53 Active Aeroelastic Wing

Fuel efficiency, endurance, and noise requirements are pushing modern aircraft to lighter, more flexible designs. This causes the structural modes to occur at lower frequencies increasing the coupling with the rigid body dynamics. The traditional approach to handle aeroservoelastic interaction is to design gain-scheduled flight control laws based on the rigid body dynamics and then use filters to avoid exciting the structural modes. This decoupled approach may not be possible in future, more flexible aircraft without reducing the flight control law bandwidth. Linear parameter-varying (LPV) techniques provide a framework for modeling, analysis, and design of the control laws across the flight envelope. This chapter applies LPV techniques to the roll control of NASA Dryden’s X-53 Active Aeroelastic Wing testbed. LPV techniques are first used to analyze a gain-scheduled classical controller. Gain-scheduling is still the dominant design method in industrial flight control laws and LPV analysis tools can play an important role in certifying the performance of these systems. Next, an LPV controller is designed and its performance is compared against the gain-scheduled classical controller. All results are obtained with a set of LPV tools which makes use of object-oriented programming to enable easy construction and manipulation of LPV models.