Fundamental Study of Momentum-Exchange-Impact- Damper-Based Robust Landing Gear

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 (MEIDs). An active/passiveHybrid-MEID (HMEID), which included an active actuator, was proposed, and stiffness control was applied. The stiffness control method controls spring coefficient between the damper mass and the body mass. The MEIDs’ performances are evaluated by the maximum rebound height, which is proportional to mechanical energy of the spacecraft. However, the time responses of the energies have not been explained. In addition, the effectiveness of MEIDs was evaluated only in a one-dimensional motion simulation. This paper includes theoretical analyses, simulation studies, and experiments. The time responses of the energies of MEIDs are discussed. This paper proposes a robust landing gear system for spacecrafts using HMEID and evaluates its robustness against ground stiffness variation. In this paper, MEIDs are applied to a mass-damper-spring-model, which takes ground viscosity into account. Effectiveness of the proposed model is verified by simulations and some experimental results. Nomenclature c c = contact damping coefficient of the damper mass, N ⋅ s/m d c = damping coefficient of the MEID spring, N ⋅ s/m f c = damping coefficient of the soil, N ⋅ s/m fg c = damping coefficient of the linear guide, N ⋅ s/m ) (t Fa = thrust force of the actuator, N rg