Fixed time active disturbance rejection control for rotational speed of variable cycle engine

The variable cycle engine (VCE)’s strong internal coupling and high uncertainty present substantial control design challenges. To address these issues, this paper proposes a rotational speed control strategy based on fixed time active disturbance rejection control (FTADRC). This method is designed to ensure precise and rapid control under complex and dynamically varying operating conditions. A fixed time extended state observer is developed to accurately estimate lumped disturbances and unknown states. Additionally, a fixed time sliding mode controller is designed to effectively mitigate uncertainties and enhance the system's dynamic performance. The stability of the proposed system is rigorously analyzed, and an upper bound on the convergence time is established. Simulation results validate the effectiveness of the proposed approach, demonstrating its capability to estimate disturbances and states rapidly and accurately. The findings indicate that the method enables faster convergence of rotational speed to the reference value, highlighting its practical engineering significance.