Robust gain-scheduled control for vertical/short take-off and landing aircraft in hovering with time-varying mass and moment of inertia

This paper presents a robust gain-scheduled control approach for planar vertical take-off aircraft dynamics. The uncertain properties of the aircraft mass, moment of inertia, and the non-minimum phase parasitic coupling are all addressed by considering a reasonable range in the progress of controller design. The realized control law is not implemented as a function of the unmeasurable coupling parameter as has been done in previous works. After a system-variable scaling process for the dynamic normalization and a control input transformation to ensure the controllability of the dynamics in a linear parameter-varying representation, the composite control law is used to address all the inherent uncertainties of the mass, moment of inertia, and parasitic coupling parameter. The composite control law consists of a linear state-feedback gain-scheduled matrix, constructed from parameter-dependent linear matrix inequalities algorithms, and a non-linear control law for thrust manipulation to eliminate the effect of gravitational disturbance. The design is then demonstrated by a time response simulation.