Research On Simplified Method Of Control-oriented Model For Hypersonic Vehicle

Hypersonic air-breathing vehicle is a promising and cost-efficient technology which can providerapid global-response capabilities for launching low-earth-orbit satellites. Although numerouschallenges remain, recent successes with NASA’s X-43a and renewed research activities through outthe aerospace community suggest that this technology may be on its way to assuming a role in thenext generation of aviation.Design of such vehicles is a very challenging task. Dynamic models of these vehicles tend to behighly complex and multi-disciplinary due to strong interaction between aerodynamics, propulsion,structure, and control. As a result, developing low-order models with sufficient fidelity becomes vitalin early stages of vehicle design. In this paper, several kinds of optimization methods are used to fitthree different models. The truth-model with the method of trust-region turn out to be the best.Despite the simplifications of the curve-fitted model, the model mimics the dynamics of the truthmodel with a reasonable degree of accuracy. Simulation results show that the curve-fitting modelspossess high fidelity. Nevertheless, significant mismatch between the truth model and the curve-fittedmodel does exist, any control law designed on the basis of analytical models derived from the curvefitted model will have to be robust to these modeling inaccuracies.The non-minimum phase behavior of the model stems from the coupling of the elevator to the liftand drag forces. In this paper, a method of simplification is used to obtain control-oriented model. Thecontrol law designed based on the control-oriented model with the method of feedback linearizationand LQR control demonstrate good tracking performance.