Altitude Control of Stratospheric Aerostat Based on $\boldsymbol{H}_{\infty}$ Mixed Sensitivity

A high-altitude balloon is a stratospheric aerostat that utilizes wind field characteristics at different altitudes for horizontal movement. Its hovering altitude dictates the direction of its horizontal motion, and precise, reliable altitude control is crucial to ensure it operates within the designated hover range. Traditional Proportional-Integral-Differential (PID) algorithms suffer from slow dynamic response and weak disturbance rejection. This paper first constructs a vertical dynamic model of the stratospheric aerostat using a mechanistic approach. Based on this dynamic model, an <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{H}_{\infty}$</tex> mixed sensitivity controller is designed, and its tracking and disturbance rejection capabilities are simulated. Simulation results demonstrate that, when considering external disturbances, the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{H}_{\infty}$</tex> mixed sensitivity controller exhibits superior dynamic response and disturbance rejection compared to the PID controller.