Three-dimensional enclosing control for stratospheric airship to circumnavigate a moving target

This paper addresses the problem of a stratospheric airship flying around a time-varying velocity moving target in a three-dimensional space under external disturbance. In order to achieve a spiral shape circumnavigation around the moving target, it is necessary to keep the same altitude as the moving target with time-varying height vertically while keeping a fixed circle radius around the moving target at the horizontal plane. First, based on the air current estimator, we design different guidance laws for different target tracking methods on the horizontal and vertical planes respectively, which can obtain the expected velocity and the expected angular velocity. Second, an adaptive backstepping attitude controller to track the desired yaw rate is introduced by estimating the boundaries of dynamic couplings and unknown disturbance. Finally, a velocity controller is added to track the desired velocity. Numerical simulations show the validity of this algorithm.