Accurate Recovery Trajectory Planning and Control of the First Sub-stage of Launch Vehicle

With the launch vehicle recovery becoming the hotspot in the field of spaceflight, the parachute recovery technology gets more attentions. In this paper, the first sub-stage of launch vehicle parafoil (FSSP) recovery technology is studied. In order to realize accurate and safe homing of FSSP, a 6-DOF mathematical model of the FSSP is established, and a multiphase homing trajectory planning scheme is designed according to the flight process. The homing trajectory of the FSSP is divided into radial flight phase, hovering phase, upwind phase and flare phase, and each phase is elaborated and planned. On this basis, the longitudinal controller and the lateral controller are designed separately. And then the trajectory tracking controller (TTC) is planned base on them to track the predetermined trajectories. The simulation results show that the homing scheme of the FSSP planned in this paper is effective and feasible. The designed TTC can efficiently overcome the external interference and track the predetermined trajectories quickly and stably, which lays a foundation for the subsequent research on the launch vehicle accurate recovery.