A Low-Cost Azimuthal Control Method for Stratospheric Balloon Gondolas

Abstract

This study addresses the control method of the azimuth direction of a stratospheric balloon gondola with simple and low-cost system. Many azimuthal control methods of the gondola have been developed mainly to achieve accurate pointing of astronomical observation instruments. As progress of technology, such systems have become complicated and expensive. On the other hand, as variety of balloon mission increasing, demands for azimuthal control system with rough accuracy, simple and small system, and low cost are also rising recently. This study proposes an azimuth control method with only a motored decoupler. The motored decoupler is an attitude control device to twist and untwist the suspension not to transfer torsion torque of the suspension and the rotation of the balloon envelope. However, the mechanism can also be used to generate torsion torque for azimuthal control of the gondola. This study aims to achieve the azimuthal control capability with the motored decoupler. The control law with observable parameters was derived by linear quadrant regulator (LQR) method. The control law was evaluated by some numerical simulations. As the result, the proposed method is concluded useful for actual balloon missions.