A Robust Thrust Control Schedule with Self-Adaptive Compensation for Gas Turbine Engine Performance Degradation

Accurate thrust control is vital for efficient gas turbine engine operation, yet direct in-flight thrust measurement is unavailable. Most engines rely on speed control schedules, which suffer from unplanned dead zones and poor throttle-to-thrust linearity—compromising pilot handling and fuel economy. We propose a robust thrust control schedule to improve the thrust-to-throttle relationship. It integrates two intermediate/idle thrust estimators, a degradation estimator, and a reference thrust estimator. The first intermediate/idle thrust estimator provides baseline estimates of intermediate and idle thrust. The degradation estimator compensates thrust deviations caused by engine degradation. The second intermediate/idle thrust estimator updates its estimates online using compensated estimates to track degradation. The reference thrust estimator then uses outputs from the second estimator and linearly interpolates the current power lever angle to determine reference thrust. The proposed schedule is evaluated under the considered degradation conditions. CLM-based simulations evaluate its effectiveness during the early-stage degradation period, while the micro-turbojet ground experiment demonstrates the proof-of-concept implementation of the outer thrust-loop structure.