QFT/μ Robust Dynamic Inversion Control Of Hypersonic Vehicle

Hypersonic vehicle has important strategic significance and a high application value. Thecontrol problem of a cruising flight hypersonic vehicle is reasearched, based on the needs ofthe development of hypersonic technology. The research issues include nonlinear, instability,non-minimum phase characteristics, coupled of multi-input multi-output control problems. Arobust dynamic inversion control design method with high value of engineering applicationsis presented, which achieves coordinated control of stability and maneuverability over widerange of dynamic pressure and Mach number.The kinematics and dynamic models of a generic hypersonic and its flight aerodynamicparameters are established, the characteristics are analyzed based on the models. Relative tothe normal aircraft, hypersonic vehicle has its own typical characteristics, which are mainlyreflected in the uncertainty, nonlinear, coupled, and unstable/non-minimun phasecharacterstics. With the conclusions of the analyzing, the control ideas and control methodsare made.Concerning the nonlinear problem, uncertainty problem of hypersonic vehicle pitchchannel, a μ synthesis robust dynamic inversion control method is presented: the dynamicinversion controller is used in the inner-loop and a robust controller is used in the outer-loop.The control method is completed in two parts, first, the vehicle model is simplified, the affinenonlinear model is divided into the speed loop and slow loop, accordance with the principle ofseparation of time scales. The controllers both of fast loop and slow loop are designed. Secend,the uncertainty modes are made, a robust controller is desing via D-K interation. Simulationresults show that the designed controller has a good robustness to the uncertainty of the thesystem.Concerning the unstable/non-minimum phase characteristics of the hypersonic vehicle, aQFT robust nonlinear control method is introduction. Based on the traditional design method,the QFT design theory is extended to the nonlinear and unstable/non-minimum phase system.Schauder fixed point therem proves the feasibility of the feedback system equivalent lineartime invariant, Golubev algorithm using MATLAB simulation gets the nonlinear systemslinear time invariant equivalent transfer model. A new stable/minimum phase model is gotform reconstructing of the unstable/non-minmum phase model. A robust controller is designedin the IED shaping environment, the control is more accurate bacuse of accounting of theunstable/non-minimum phase characteristics.On the basis of the study in Chapter3and Chapter4, for the limitations of μ synthesis and QFT in the hypersonic vehicle control, a QFT/μ robust dynamic inversion control methodis presented. Dynamic inversin fast loop controller reduces the degree of nonlinearity of thesystem to improve the dynamic characteristics; the μ controller is as the QFT initial controller,the order of th controller is reduced by using of QFT controller redesign. Simulation resultsshow that the controller meets the control requirements of accuracy and robustness, at thesame time easy to grasp and engineering applications.The hypersonic vehicle lateral channel is a multi-input multi-output system with strongcoupling, an improve QFT MIMO design method is presented. First the classis MIMO designmethod are introduced and described, and then the limitations of the method in themultivariate unstable/non-minimum phase system deign is analyzed. A lateral channelcontroller is designed using a drill progressive design method. Simulation results show thatthis control method can effectively inhibit the coupling between lateral channel, and it is apractical control method.