Performance optimization study of a Common Aero Vehicle using a Legendre Pseudospectral Method

Abstract

The problem of performance optimization of a Common Aero Vehicle (CAV) is considered. In particular, the CAV is modeled as an unpowered high lift-to-drag ratio Earth penetrating re-entry vehicle. The CAV mission design problem is to determine a steering command that takes the CAV from a known initial state to a target on the surface of the Earth while optimizing a given performance index and satisfying all of the constraints imposed during flight. The CAV mission design problem is formulated as an optimal control problem. The optimal control problem is transformed to a nonlinear programming problem using a Legendre Pseudospectral Method. The nonlinear programming problem is then solved using a sparse nonlinear optimization algorithm. Once a solution to the CAV mission design problem is obtained, three main studies are conducted. First, the accuracy of the Legendre Pseudospectral Method is evaluated and the desirable characteristics of the solution to the CAV mission design problem are defined. Second, a study is conducted to demonstrate the effect of the parameters on the performance of the CAV. This parametric study demonstrates the use of the Legendre Pseudospectral method as a design tool and provides insight to the behavior of the CAV. Third, a preliminary investigation is performed on the real-time application of the Legendre Pseudospectral Method to the CAV mission design problem. This real-time analysis includes an assessment of the robustness of the solution to realistic environmental disturbances.