Modeling And Control For Air-breathing Hypersonic Vehicle With Variable Geometry Inlet

In recent years,air-breathing hypersonic vehicle(AHV)have attracted a great deal of attention,due to the advantages of high speed,stable performance,etc.However,the structure of the traditional air-breathing hypersonic vehicle with fixed geometry inlet(AHV-FGI)cannot ensure the performance of cruise,especially the hypersonic vehicle has a low Mach number status.The variable geometry inlet of scramjet with translating cowl means there is a lip in the front of the inlet,which could be adjusted forward or backward with the requirements of flight control.This paper has done the following research about the air-breathing hypersonic vehicle with variable geometry inlet(AHV-VGI).We analyzed the forces situation of AHV-VGI using the shock expansion wave theory,and obtained analytical expressions for aerodynamic forces of AHV-VGI through the least squares fitting method.Next,we illustrated the influenced on dynamic characteristics of AHV caused by translating cowl,which also provided a relevant basis for the design of AHV-VGI control system.On the parts of control system design,considering the complexity,strong coupling and uncertainties existed in AHV-VGI longitudinal model,we designed a nonlinear controller based on adaptive type-2 fuzzy system which has a strong ability to deal with nonlinearity and uncertainty.The simulation results show the robustness of the designed controller,and we illustrated the advantages of translating cowl from the perspective of control field.Furthermore,we also taken into account the disturbances introduced by parameters perturbation and external environment in AHV-VGI control system,and proposed a fuzzy adaptive type-2 control method based on nonlinear disturbance observer.The disturbance observer is used to observe the disturbance online and compensate the adaptive type-2 fuzzy controller.Numerical simulations show that the compensation control design based on disturbance observer has good tracking performance for given instruction and stronger robustness.It also shows the advantages of AHV-VGI control system in the presence of disturbances.