Multidisciplinary Design Optimization Of Suborbital Vehicle Based On Approximation Model

Suborbital vehicle as a new type of aircraft are widely studied in the world, because it does not need to have the capacity to go into earth orbit. It has the advantages of small size, low energy consumption, small maintenance cost, flexible mode of launch, reusable, etc. relative to the orbiter vehicles. Multidisciplinary design optimization(MDO) method can obviously shorten the design period of product, and improve the quality of design in aerospace and other complex design domains. Approximate model can solve problems of complex and nonlinear model, as one of the key technologies of MDO. Establishing the subject approximation model to replace the original complex model, which can keep the accuracy of the model, and can accelerate the optimization efficiency, reduce the design cost. In this paper, approximation model theory and aerodynamics approximation modeling of reusable suborbital vehicle was studied, and the applications of MDO on return trajectory of suborbital vehicle were analyzed.Firstly, the approximation modeling method and design of experiment theory was studied. The advantages and disadvantages of fitting type and interpolation type approximation model were analyzed.Secondly, CAD parameter processing and numerical simulation was developed on the reference shape of suborbital vehicle. Then, the automation integration method on aerodynamics model was built and the approximate modeling analysis of aerodynamic disciplines was analyzed.Thirdly, the amelioration of Radial Basis Function(RBF) model was put forward by using the expected improvement function, and significantly improved the convergence speed and prediction accuracy of the approximation of the aerodynamic on suborbital vehicle.Finally, the MDO task on return trajectory of suborbital vehicle was analyzed. The subject of geometric shape, aerodynamic, structure, ballistic was integrated by using the amelioration of RBF model. Collaborative optimization method was used in the optimization of the reference shape on suborbital vehicle. The optimization results show that on the premise of meeting all constraints, the aerodynamic performance of suborbital vehicle was improved, and the quality was even been reduced.In the paper, the approximation model of suborbital vehicle, the method of aerodynamic modeling and simulation automation integration, and the optimization process and integration method of MDO was reasonedly studied. The RBF model of based on expected improvement function was put forward, and the overall scheme and processes of MDO on suborbital vehicle was established, which has some reference for the overall design of suborbital vehicle.