A rule-based online energy management strategy for long-endurance stratospheric airships

Abstract

Stratospheric airships are typically equipped with photovoltaic energy systems to ensure consistent and controlled long-duration flights. To maximize the utilization of energy generated by the airship's solar array for mission requirements while maintaining energy balance in a computation-efficient manner, we analyzed the characteristics of global optimal energy profiles obtained through the pseudospectral method and distilled them into a rule-based energy management strategy. The rule-based strategy simplifies solving large-scale nonlinear optimization problems posed by pseudospectral method into solving problems for optimal rule logic thresholds, which greatly enhances the speed of strategy generation. Leveraging rapid strategy generation, we developed an online energy management scheme that can achieve closed-loop control by repeatedly updating the rule logic thresholds based on the feedback states. Simulation results demonstrate that the proposed energy management strategy is more effective in utilizing energy to meet mission requirements compared to the two-phase energy management strategy from a previous study. Notably, the online energy management scheme can adapt to uncertainties such as modeling errors, rather than merely providing an open-loop plan.