Design of entry trajectory tracking law for a hypersonic vehicle via inversion control

A nominal altitude-velocity longitudinal entry trajectory is planned and tracked for a Generic Hypersonic Vehicle (GHV) in this paper. The entry corridor is presented which is defined by the dynamic pressure, normal acceleration, heating constraints, and the so-called Quasi-Equilibrium Glide Condition (QEGC). The flyability of the vehicle along the nominal trajectory is carefully analyzed for further validation of the selected nominal trajectory. The control scheme mainly consists of two loops: a guidance loop and an attitude loop, of which the latter is separated into the slow and fast loops with the time-scale separation theory. Inversion control is employed in these three loops, and an integration feedback approach is especially added into the inversion controller to eliminate the tracking error. Simulations demonstrate that the nominal trajectory is designed appropriately and tracked well.