Robust Adaptive Control Of Hypersonic Vehicles Based On Guardian Maps Theory

Hypersonic vehicles feature distinguished military and economic value, as a result that hypersonic flight technology becomes the research hotspot in the field of aerospace. Compared with traditional vehicles, the dynamic model of HSV features higher nonlinearity, tighter coupling and larger uncertainty. Moremore, the designed controllers need to have more stringent performance demands as well as stability requirements. Therefore, the development of models and control systems for HSVs can be very challenging.In order to master the dynamic characteristics of HSVs, the control-oriented longitudinal dynamic model is firstly established based on flight mechanics, aerodynamics and classical mechanics, as well as other fundamentals of physics. Following that, a Linear Parameter-Varying(LPV) model of the HSV has been built according to gap metric theory where the normalized altitudes and Mach numbers are chosen as scheduling variables. And then, controllers are designed based on this LPV model. In addition, with the combination of the H_?and LMI theories, robust controllers of angle of attack are designed on the nominal points selected by gap metric theory one by one. Accordingly, the control parameters over the whole flight envelop are obtained.Because there exist high nonlinearity and variable dynamic properties existing in the HSV model, a robust adaptive control method using guardian maps theory is proposed. During this design process, as long as a fixed controller architecture and initial controller gains are given, the stability region within the flight envelop corresponding to the controller parameters identified based on guardian maps. New controller parameters are yielded at the right boundary points of the stability regions. A set of allowable control parameters are automatically constructed along with the corresponding stability regions in relation to scheduling variables by executing the iterative operations. Therefore, the analytical expressions of controllers are deduced by the curve-fitting method. The simulation results indicate that the LPV model is of pinpoint accuracy. Beyond this, the robust adaptive control law guarantees global stability throughout the wide flight envelop for the HSV, and at the same time making that the system fulfills the prospective robustness demands. Furthermore, combined with the H_? robust controller, the rubustness and adaptive control performance of this designed controller are more excellent for the hypersonic vehicle.