Energy-based control of a nonlinear hybrid-propulsion aircraft system

This paper presents the integration of an energy-based control system, a hybrid-electric nonlinear aircraft model, and differentiable flight-envelope protection functions for simulation-based design workflows. A fully nonlinear 3-DoF aero-propulsive model for a propeller-driven, hybrid-electric, regional transport aircraft is presented and coupled with the Total Energy Control System (TECS). The proposed formulation explicitly addresses features that are critical in realistic hybrid-electric flight simulation, including variable-mass, power lapse, flight-envelope protection implemented through smooth blending functions, and Control Authority Allocation (CAA) in saturated operating conditions. The resulting framework supports controlled mission simulation over a wide range of operating scenarios while preserving a continuous implementation suitable for Functional Mock-up Interface (FMI) compliant workflows. Results show effective airspeed and flight-path tracking, energy-consistent climb and descent behavior, and safe operation under different mission phases. The study demonstrates that TECS can be extended from conventional and linearized models to fully nonlinear hybrid-propulsion configurations, providing a generalizable basis for advanced nonlinear aircraft control and verification-oriented simulation.