Dynamics Modeling and Analysis of a Vertical Landing Mechanism for Reusable Launch Vehicle

In this work, a vertical landing mechanism of a reusable launch vehicle (RLV) is investigated using a flexible–rigid coupled dynamics model. The presented model takes into account the four-legged landing mechanism and the main body cabin. Flexibilities of the main components in the vertical landing mechanism are considered. The hydro-pneumatic spring force and thrust aftereffect caused by the sequential deactivation of the engine are introduced separately. Several simulation cases are selected to analyze the loads acting on the landing mechanism and the dynamics behavior of the whole RLV system. Simulation results show that considering flexibility in the landing mechanism is critical for dynamics analysis under various initial conditions. The adopted RLV design is capable of achieving stable landings under specified initial velocity and attitude conditions, demonstrating its feasibility for engineering applications. Moreover, the hydro-pneumatic spring plays a crucial role in absorbing the impact of the initial landing leg, ensuring a smoother landing experience and minimizing potential damage to the vehicle.