Abstract: The ascent trajectory design problem of air-breathing combined-cycle hypersonic vehicle is studied in this paper. By considering the different characteristics of the combined-cycle engine and aerodynamics within the flight envelope, the flight strategy for turbo mode, ejecting mode, scram mode and scram-rocket mode is proposed respectively. Then, by constructing the proper attack angle profile and rocket flow profile, the infinity dimension optimization problem is simplified as the finite dimension parameters optimization problem, which can be solved effectively via the sequence quadratic program algorithm. Moreover, by using the trajectory linearization control approach, the tracking guidance law for the combined-cycle ascent phase is designed, and the principle for choosing the controller parameters to guarantee the stability and performance is also provided. In the end, the simulation is carried out and the results demonstrate the efficacy of the proposed design approach.

Key words: Hypersonic vehicle, Trajectory optimization, Ascent guidance, Trajectory linearization control