Planning and optimal control of a Venus variable altitude aerobot

Abstract

Venus has long been of interest in humankind’s understanding of how Earth, and Earth-like rocky bodies, form and evolve in our solar system. A key missing capability for our exploration of Venus are technologies which can navigate through the atmosphere recurrently and over extended periods of time, with minimal power. Recently, the Jet Propulsion Laboratory (JPL) has developed a variable altitude aerobot for operation in the Venus atmosphere. By exchanging helium gas within a dual chamber architecture, the aerobot is capable of smoothly navigating through a $10$ km tall altitude range. Although the aerobot is open-loop stable, its atmospherically dependent non-linear oscillatory behavior introduces the need for finer trajectory tracking in order to meet the mission scientific objectives. This work aims at developing a simulation and first convex optimization optimal control framework for such an aerobot architecture, targeted towards accurate mission driven altitude changes and reference tracking. A prior test conducted by JPL on a scale-size aerobot prototype in the Black Rock desert is used for the control plant model matching. Finally, we consider multiple mission driven altitude change maneuvers and show smooth trajectory tracking with minimal overshoot satisfying the operational requirements and constraints.