Robust Control Of Aero-Engines Based On H_?/Leitmann Method

The aero-engine distributed control system is a complex system.The development of the aero-engine distributed control system brings a lot of advantages.However,because of the time-delay of network control system,uncertainties caused by parameter perturbations,modeling errors and individual differences,noises and coupling,there are also many new problems and difficulties for the aero-engine distributed control system.In this paper,we made a research on the robust control method for distributed control based on a turbofan engine.According to the nonlinear model designed by thermodynamic characteristics of a turbofan engine,we established a linear state variable model with small perturbation and fitting method.It benefits to the design and simulation of controllers.Firstly,we established a model of uncertainties and noises.In order to reduce the influence of uncertainties and noises,H_?/Leitmann state regulator was established.In this state regulator,The H_? control can make the nominal system asymptotic stable and reduce the influence of noises.The Leitmann method works with the H_? control to realize the ‘Uniform boundedness' and ‘Uniform ultimate boundedness' of the uncertain system.Then we did a further research.We designed two tracking controllers with a reference model system and a new high-dimensional augmented system obtained by the state feedback with integral errors.We also proposed two new definitions,‘Uniform tracking boundedness' and ‘Uniform ultimate tracking boundedness'.In these ways,we could make the tracking problem switching to a robust controller design problem.Consider the time-delay of the system,a linear model including noises,uncertainties and time-delay is established.In this paper,we made some assumptions to determine the research direction of the time-delay and established the linear model of uncertainties,noises and time-delay.We propose a Time-Delay-H_?/Leitmann controller and then we selected the Lyapunov-Krasovskii Functional with double integral.The time-delay-dependent stability theorem is derived with the help of inequality scaling,the introduction of free weighting matrices and so on.Combined the control algorithm designed before,we designed a time-delay robust controller.Consider the Correspondence between the distributed control system and the decentralized control system.We selected a large scale system with some coupled models as the research object.There are noises,uncertainties,time-delay and coupling of other subsystems in every subsystem.Used the H_?/Leitmann control algorithm to reduce the influence of coupling and designed a corresponding H_?/Leitmann controller.