Entry trajectory generation without reversal of bank angle

Abstract

A rapid entry trajectory planning algorithm for hypersonic glide vehicles is presented in this paper, and the avoidance of no-fly zones with large cross-range is achieved. The highly-constrained entry trajectory generation mission is accomplished using an adjustable angle of attack and bank, instead of a nominal angle of attack and reversal logic of bank angle. In this way, the maneuvering capability of the vehicle is greatly improved. Moreover, as no reversal of bank angle exists in the whole flight, the control command is easier to follow. Firstly, longitudinal entry corridor with an adjustable angle of attack is built up. The drag acceleration profile is represented as five piecewise affine functions of the energy, which are adjusted to meet the requirements of the trajectory length and lateral maneuvering capability. Secondly, based on the quasi-equilibrium glide condition (QEGC), the maximum and minimum boundary of the lateral lift-to-drag corridor corresponding to the current drag acceleration profile is approximated, and the lateral profile is represented as an interpolation result of the boundaries. Finally, the parameters of longitudinal and lateral profile are found by the Newton iteration scheme with the help of a reduced order system. A combined proportional integral derivative (PID) tracker is also designed to follow the drag and heading angle profile. The approach is tested using the Common Aero Vehicle model. Simulation results demonstrate that the generated entry trajectories can avoid no-fly zone with a large cross-range and achieve the terminal conditions while satisfying all the complex path constraints.