Gain-scheduled control of PVTOL aircraft dynamics with parameter-dependent disturbance

This paper presents a gain-scheduled control approach for the vertical takeoff and landing aircraft. The non-linear aircraft dynamics are formulated as a linear parameter varying (LPV) system with external parameter-dependent disturbance, which arisen from the equilibrating between gravity force and nozzles thrust. The disturbance is dependent on the system varying parameter, roll angle, and a constant parameter denoting the normalized gravity force. The controllers are designed in terms of mixed optimization of H∞ performance for disturbance attenuation and relative stability for tracking position command in pitch-yaw plane. The characteristics of the parameter-dependent disturbance are described by an equality condition with a defined annihilation matrix. By exploring the parameter-dependence condition on disturbance into the controller design algorithms based on linear matrix inequalities (LMIs), it is showed that a better performance can be achieved than simply considering it as an external disturbance. The design results are demonstrated by time response simulations.