Reentry Vehicle Constrained Trajectory Optimization

Abstract

Generation of optimal trajectories for hypersonic reentry vehicles satisfying both boundary conditions and path constraints is a challenging job. In this research, Gauss pseudospectral method is used to solve trajectory optimization problems. An optimization implementation named Easy Gauss pseudospectral method (EGPM) is developed. During the optimization process, most common constraints are considered, such as heating rate constraint, dynamic pressure constraint, aerodynamic load constraint and geographic constraints, including waypoint and no-fly zone constraints. Two examples demonstrate the optimality of the optimization implementation EGPM. In the first example, the maximum downrange trajectory without path constraints is solved using EGPM and Gauss pseudospectral optimization software (GPOPS) respectively. Then the two results are compared and analyzed. After that, the maximum downrange trajectory imposed heating rate, dynamic pressure, and aerodynamic load constraints was optimized using EGPM. The second example generates a multi-phase trajectory satisfying waypoint and no-fly zone constraints. To keep the trajectory smooth, an improved quasi-equilibrium glide condition (IQEGC) is enforced in the example. The modified Common Aero Vehicle (CAV) data are used to support the two examples.