Research On Control Technology Based On Linear Aeroengine Model

Aeroengine is the most important machine in the modern aviation industry.For the control system,the engine is a complex object with multi variables,strong nonlinearity and uncertainty.The performance of the engine control system will not only directly affect the flight reliability and economy of the aircraft,but also endanger the life safety of the pilot.So it is of great practical and theoretical value to study advanced engine control technology..This paper takes a turbofan engine as the research object,takes the engine model at the steady-state working point as the controlled object,and establishes its mathematical model by the pumping method to design the control method.The first main work of this paper is to propose the optimal decoupling control for the internal variable coupling and external system coupling in the engine system.Because aeroengine is a multi input and multi output complex system,the change of a single input will affect multiple outputs,and the change of a single output will also affect the rest of the outputs.In this case,direct controller design can not achieve the desired effect.Therefore,it is necessary to decouple the internal system of the engine system.In this paper,an intermediate control quantity is invented to eliminate the coupling relationship between the system variables.At the same time,because the coupling between the systems will also have a coupling effect,the output of the engine system is designed to eliminate the coupling between the systems,and the optimal tracking control method is used to track the ideal output of the engine system.The second main work of this paper is to propose a neural network model reference adaptive control(MRAC)for engine system with unknown mathematical model parameters and unmodeled system dynamics.Due to the change of flight speed,altitude and other working conditions of the aircraft,the relevant parameters and system structure of the engine mathematical model will be changed accordingly,and the accurate mathematical model can not be obtained.At this time,the optimal control method or classical feedback control method can not be used to design the control law of the engine system.In order to solve the problem that the system model parameters are unknown when the aeroengine works near the steady state,the adaptive control law based on Lyapunov stability theory is used to design the control law,the Lyapunov function is designed,and the stability proof of the control system is given.At the same time,due to the unknown dynamic characteristics in the system,when some flight states change,the system model can not accurately reflect all the dynamic characteristics of the system,that is,there are unmodeled dynamics in the model.For the unmodeled dynamics,the neural network is used to train and get the estimated value,which is used as the compensation and the adaptive control law,so as to get the Neural network model reference adaptive control law.Finally,the simulation results show that the decoupling ability of the above optimal decoupling control method can reach the better performance index under the internal and external coupling.The neural network model reference adaptive control method can realize the adaptive tracking control of the engine system under the uncertainty factors.The simulation results show that the two control methods designed in this paper are effective for the aeroengine control under the above two conditions,which opens up a new idea for the research of engine control technology,which has certain engineering value.