Research On The Distributed Control System Of Variable Cycle Engine

The variable cycle engine has the mutual advantages of the turbofan engine and the turbojet engine,which makes it the ideal power device for the next generation multipurpose fighter.In comparison of the general engine,the complexity of variable cycle engine's control system increases because of the increase in the number of control variables and actuator,leading to the fact that the traditional centralized control system can hardly meet the needs of the variable cycle engine.The distributed control system,which has various advantages when compared to the centralized control system in terms of weight,reliability and maintainability,is feasible in the design of variable cycle engine control system.In this paper,research in variable cycle engine modeling and multivariable control are proposed,based on which,a distributed fault tolerant control system of variable cycle engine is built.Besides,hardware in the loop simulation test is carried out to verify the effectiveness of the proposed method.The remainder of this paper is organized as follows:Firstly,a component level nonlinear model of variable cycle engine with double external culvert is established when the state is above idle state.In the process of modeling,the data of design point and the characteristic curve of each component provided by GasTurb are taken into consideration.In addition,the influence on the characteristics of the compressor and turbine components resulted by the variation of guide blade angle and area of guider has been emphasized.In conclusion,the model illustrated above has the ability to reflect two typical working modes of variable cycle engine and transition state during the switching process.Secondly,the study of multivariable robust control for a variable cycle engine is carried out.Additionally,a suitable dimension state space model is established by least square fitting method and the controller of mode switching in Double external bypass mode and Single external bypass mode is designed based on ALQR control algorithm.Furthermore,a fault tolerant control is achieved by the method of control law reconstruction.In view of the mode switching control,the method of thrust control in variable cycle engine is put forward and a controller containing three variables(The thrust,The speed of low-pressure rotor,The surge margin of fan),is designed based on ALQR control algorithm,achieving the closed loop control of mode switching in variable cycle engine.Thirdly,a distributed fault tolerant control system based on TTP/C bus for a variable cycle engine is built,which contains 7 intelligent nodes.The software and hardware of each intelligent node and host computer monitoring software are designed.Combined with the self-designed variable loop engine analog interface system,the hardware in the loop simulation test platform for the distributed fault tolerant control system of the variable cycle engine is constructed,and the real-time performance of the platform is optimized.Finally,the variable cycle engine distributed control system hardware in the loop simulation test is carried out,which can be divided into two parts:(1)The simulation test of both typical mode control and mode switching process control.(2)The simulation test of distributed fault tolerant control for variable cycle engine under failure of different nodes.The simulation results indicated that the multivariable controller designed in this paper has good performance in the typical mode control and mode switching process control of variable cycle engine,meeting the strict control requirement,verifying the effectiveness and feasibility of the distributed fault tolerant control system for the variable cycle engine illustrated in this paper.