Path-Following Control of Underactuated Stratospheric Airship With Constraints and Disturbances Using Time-Delay Observer

This paper investigates the path-following control problem for an underactuated stratospheric airship with unknown dynamics, external disturbances, and constraints. A novel error-constrained Serret-Frenet frame has been utilized to drive the underactuated airship to track the predefined path. A novel control approach that combines backstepping and time-delay observer (TDO) has been employed for tracking the desired forward velocity and estimating unknown dynamics and disturbances without the details of the airship's dynamics. The position error and velocity constraints of the airship are handled by nonlinear mapping. The proposed control scheme can drive an underactuated airship to track the predefined path and the constraints requirements are never violated. Simulations demonstrate the effectiveness and advantages of the proposed control scheme.