Flight envelope quantitative division of hypersonic vehicle based on gap metric

Considering that the existing flight envelope division methods of hypersonic vehicle were too subjective and complicated, a new division method was introduced based on the theory of gap metric. The theory of gap metric was introduced, and the computing method of gap between linear systems was given. Here the gap metric was taken as the quantitative index to analyze the extent of the model characteristics' variation to confirm the frontier of subrange. Based on the result obtained above, the way of choosing the nominal state point was proposed by analyzing the gap metric of all points within the subrange. With the living example of some hypersonic vehicles, the analysis of amplitude-frequency characteristics for nominal state point and the simulations of closed-loop control system prove that the result of envelope division is reasonable, which indicates the method proposed is effective and able to increase the level of automation of envelope division.