Enhanced Flight Envelope Protection: A Novel Reinforcement Learning Approach
Akin Catak, Ege C. Altunkaya, Mustafa Demir, Emre Koyuncu, Ibrahim Ozkol
TL;DR
This work addresses safe flight envelope protection for the longitudinal axis under nonlinear aircraft dynamics by introducing a reinforcement-learning agent trained with a reward that penalizes envelope violations and tracking errors. The approach uses Deep Deterministic Policy Gradient (DDPG) within a nonlinear F-16 model integrated with an INDI control law, with the agent outputting restorative pitch-rate commands $q_{rest}$. Key contributions include a novel RL-based envelope protection method that reduces design burden and improves performance in coupled maneuvers, demonstrated across multiple scenarios and Monte Carlo tests. The results suggest RL-enabled envelope protection offers carefree flight capabilities with scalable applicability, paving the way for full-envelope protection including lateral dynamics.
Abstract
This paper introduces a flight envelope protection algorithm on a longitudinal axis that leverages reinforcement learning (RL). By considering limits on variables such as angle of attack, load factor, and pitch rate, the algorithm counteracts excessive pilot or control commands with restoring actions. Unlike traditional methods requiring manual tuning, RL facilitates the approximation of complex functions within the trained model, streamlining the design process. This study demonstrates the promising results of RL in enhancing flight envelope protection, offering a novel and easy-to-scale method for safety-ensured flight.
