Optimization of periodic optimal cruise for a hypersionic vehicle

Raising the fuel efficiency per mile is a crucial criterion of trajectory design for a hypersonic vehicle. This paper presents several numerical methods to such problem based on HL-20 model. This is a typical Optimal Periodic Control (OPC) problem. By simplifying the HL-20 model, the new high-fidelity guess is given to obtain a more reliable optimal solution. Furthermore, the optimal solutions are obtained by applying the software-SNOPT and IMSL to solve the nonlinear optimization problems with enough constraints and then the contrast between the obtained results is shown by using different auxiliary calculation tools. Actually, the cruising mode with periodic altitude and velocity is more fuel-efficient than the previous results also by the methods of OPC, thus, better than the traditional one with constant altitude and velocity. Therefore, an improved trajectory can be realized based on the constant optimal mode. The simulation results verify the effectiveness of the method.