Online Trajectory Planning for Parafoil First-Stage Booster System in Complex Wind Field

Abstract

The parafoil has excellent gliding ability and operability for recovery of the first-stage booster, which makes the landing point of the first-stage booster controllable. However, during the recovery process, the wind field changes in real time due to changes in altitude and turbulent wind, which has a great influence on the trajectory and landing point of the parafoil recovery system. In order to realize accurate homing of the parafoil first-stage booster combination (PFC) in a complex wind field, an online trajectory planning algorithm based on the quartic Bézier curve is proposed in this paper. This algorithm combines the Bézier curve with the multiphase homing method and proposes a method to calculate the control points of the Bézier curve according to the time-varying wind field. First, a six-degrees-of-freedom model of the PFC is established, and the motion characteristics of the PFC are analyzed. Then, the drift of the PFC caused by the wind field is calculated, and it is superimposed on the target landing point to obtain the virtual landing point. On this basis, the quartic Bézier curve is used to plan the homing trajectory. The simulation results show that the algorithm has high computational efficiency for online trajectory planning. It can realize accurate homing of the PFC in complex wind fields with continuous unilateral brake deflections, which makes it conducive to practical application.