Robust Gain-Scheduling Control Of Hypersonic Vehicle In Near Space

For cost efficient and time reduced ?ights in both commercial and military areas,air-breathing engine powered hypersonic vehicle with its significant dual-use value, be-comes the main research direction of current near space ?ight technology. As the aero-nautics and space technology's integrated product, hypersonic vehicle features complex?ight environment, wide range of ?ight envelop, variable dynamic characteristics, strin-gent control requirements and so on, all of which propose many new research challengesto ?ight control system design. For the core control problems of our country's futurelong-distance maneuver hypersonic vehicle in near space, the studies are extended pro-gressively and in-depth in turn from model building, object analysis, control method andcontrol system design. The research issues include large-span maneuver ?ight control,trajectory/attitude coordinated control, servoelastic stability, and input constrained con-trol problems. A practical and feasible multi-loop gain-scheduling control system designand synthesis method is presented, which achieves coordinated control of stability andmaneuverability over wide range of dynamic pressure and Mach number.To characterize the major hypersonic vehicle dynamics and reveal its potential con-trol problems, an integrated and analytical modeling method is used to build control-oriented ?exible air-breathing hypersonic vehicle model. The obtained model can de-scribe the multidisciplinary crosscoupling effects unique to hypersonic vehicle, and pro-vide a research platform for this dissertation.To better understand the dynamic behaviors of hypersonic vehicle and the potentialeffects of various couplings, and assess their effects on ?ight control system, the uniquedynamic characteristics of hypersonic vehicle are analyzed from the control point of view.Based on the analysis results, several core control problems to be researched are extractedand analyzed. The obtained analysis results help to understand the physical nature of itscomplex dynamics, make its control problem concrete, and guide the follow-up controlmethod research and control system design.Concerning the nonlinear control problem, input constraint problem and model un-certainty problem of hypersonic vehicle model, these problems are transformed into therobustness framework of linear parameter-varying (LPV) system with structural perturba- tion of dynamic uncertainty, time-varying parameters and memoryless nonlinearity. As aresult, two new robust gain-scheduling control methods are presented with bounded in-duced ?2 norm performance. The obtained control methods are used to deal with thelarge-span maneuver ?ight control problem, saturation problem of control surface, mod-eling uncertainty and time-varying characteristics of hypersonic vehicle.Based on the multi-time-scale property of hypersonic vehicle motion, a multi-loopcontrol structure is proposed. The control structure combines pitch rate loop, attitudeloop, and trajectory loop as sequential feedback structure. As a result, the full controlproblem is decomposed into three lower-order subproblems, which are solved at differentfrequency band. A ?ight control system that is gain-scheduled over dynamic pressureand Mach number is designed. For comparison, a nonlinear control system is designedwith feedback linearization method. Nonlinear simulation evaluation demonstrates thatthe developed multi-loop gain-scheduling control is suitable for solving the core controlproblems of hypersonic vehicle, and is a practical and effective ?ight control system de-sign and synthesis method.