Robust Landing Gear System Based on a Hybrid Momentum Exchange Impact Damper

When a spacecraft lands, a large shock load can lead to undesirable responses such as rebound and tripping. The authors previously discussed the problem of controlling these shock responses using momentum exchange impact dampers. An active/passive hybrid momentum exchange impact damper, which included an active actuator, was proposed. Themomentum exchange impact dampers’ performances are evaluated by themaximum rebound height, which is proportional to themechanical energy of the spacecraft. However, the time responses of the energies have not been explained. In addition, the effectiveness of momentum exchange impact dampers was evaluated only in a onedimensional motion simulation. This paper includes theoretical analyses, simulation studies, and experiments. The time responses of the energies of momentum exchange impact dampers are discussed. This paper proposes a robust landing gear system for spacecraft using a hybrid momentum exchange impact damper and evaluates its robustness against ground stiffness variation. First, momentum exchange impact dampers are applied to a mass-damper-spring model, which takes the ground viscosity into account. Next, the proposed model’s effectiveness is verified by simulation studies and some experimental results. Finally, this paper studies two-dimensional motion analyses to address rotational motion.