Research On Gas Path Fault Tolerant Control Of Aircraft Engine

Due to aerodynamic load,thermal load,gas erosion,casing deformation and inlet distortion,aero-engine may suffer from gas path failure in its work.Gas path failure will reduce the thrust and dynamic performance of the engine and affect the maneuverability of the aircraft.In order to restore thrust and dynamic performance of aero-engine,fault-tolerant control of aero-engine gas path fault was studied in this paper.Firstly,in view of the characteristics of complex control structure,the poor adaptability to the faulty engine and the conservativeness of Min/Max switch logic in traditional control system,model predictive control,which can explicitly handle engine constraints,was used to realized engine speed control and constraint managenment.In model predictive control,the equilibrium manifold expansion model was used as the predictive model to ensure that the predictive model can reflect the dynamic characteristics of the engine in a wide range.The interior point method and the alternating direction multiplier method were used for model predictive control.Simulation verified the feasibility of the model predictive control and the real-time performance of the two algorithms was compared.Secondly,in order to restore the thrust of the fault engine,it was necessary to use the thrust command model to obtain the target value of thrust recovery.When using the closed-loop control method to restore thrust,the thrust estimator was needed for feedback.In the design of thrust command model,gradient boosting regression tree with less computation and large storage space,and deep neural network model with large computation and less storage space were used.In the design of thrust estimator,a deep neural network with strong generalization capability and large amount of data processing ability was used.The component-level model was used to collect steady-state data.The thrust command model was established and verified.Dynamic data were collected by component level model and a thrust estimator was built.Its accuracy was verified at high altitude cruise points and degradation conditions.Finally,the fault tolerant control of gas path fault was carried out.By analyzing the characteristics of three stages in the process of engine acceleration,the dynamic performance recovery was realized by using model predictive control and surge margin constraint management.Using the thrust command model and the thrust estimator,the thrust recovery control of the fault engine was realized by using the dual-loop control structure which combines model-free adaptive control and model prediction control.Simulation verified the effectiveness of dynamic performance recovery and thrust performance recovery.