Trajectory optimization for reentry vehicle based on sequential gradient-restoration algorithm

To study the application of the sequential gradient-restoration algorithm in lifting reentry vehicle(LRV) trajectory optimization, transformation process of control constraints and trajectory constraints was presented. Considering strong nonlinearity of reentry dynamic, state integral was introduced, and update method of the sequential gradient-restoration algorithm was improved. The practicability of improved algorithm for quasi-smooth trajectory optimization of lifting reentry vehicle was comparatively analyzed. Simulation results show that transformation method of constraints is effective, and the convergence speed and optimization results of the improved algorithm are better than those of the original algorithm. A quasi-smooth trajectory of LRV satisfying trajectory constraints and boundary conditions can be obtained in the short period of time by the improved algorithm. Therefore, the improved algorithm has high potential for application and development in trajectory optimization of vehicle.