Abstract: In view of the limited buffer capacity and adjustment capacity of friction buffer in the cable system for the reusable rocket landing, an inverse problem design method of hydraulic buffer device based on least square method and system dynamic characteristics is proposed. This method can achieve the specific kinematic characteristics of the landing rocket by adjusting the cam shape of the control valve and the initial pressure of the accumulator in the hydraulic buffer device, enabling the rocket to land safely and stably under the limited buffer displacement and the minimum buffer acceleration. The accurate and efficient multibody dynamics model of the proposed system is established. The simulation calculations are carried out under different working conditions. The simulation results show that the hydraulic buffer device designed according to the proposed method can decelerate and buffer the landing rocket according to specific kinematic characteristics, and has strong deceleration and buffer ability. For the landing rocket with different mass and landing position deviation, it has the ability to automatically adjust hydraulic resistance to keep the same kinematic characteristics of the rocket.

Key words: Reusable rocket, Landing system, Multibody dynamics, Hydraulic buffer, Inverse problems