RLV´s re-entry trajectory optimization based on B-spline theory

A new computational optimization approach is proposed to generate Reusable Launch Vehicle (RLV)´s re-entry trajectory. With the application of the new method, all state variables are approximated by B-spline curves. After the trajectory optimization problem is transformed into a general nonlinear programming (NLP) problem, which parameters to be optimized are coefficients of the B-spline curves and control variables at every node and interpolation point, a nonlinear programming solver is selected to determine the parameters. Simulation results show that the optimized re-entry trajectories satisfy the path constraints, and can accomplish the desired terminal conditions. Compared with the Direct Collocation with Nonlinear Programming (DCNLP) method, the new approach is better in continuity and has fewer coefficients to be determined; moreover, the new approach can achieve better performance index.