Three-dimensional ascent trajectory optimization for stratospheric airship platforms in the jet stream

Abstract

Full three-dimensional optimal-ascent trajectory design is addressed for a stratospheric airship platform, considering real jet stream and flight constraints. The target airship's equations of motion are first constructed by including wind effects and its inherent features such as added mass and buoyancy effects. For realistic trajectory optimization, additional necessary modeling of the jet stream, aerodynamic force, and thrust are established based on a flight test, wind-tunnel test, and meteorological observation data. In addition, detailed path constraints such as the target airship's performance and local airspace are also accounted for. The sequential quadratic programming approach is employed as a numerical solver for both minimum flight time and minimum-energy performance indices. The solutions obtained satisfy all of the constraints and are largely affected by the jet stream of high wind speed. From the optimization results, the minimum flight time trajectory is recommended due to the low flight performance of the airship in contrast to its huge size and heavy weight.