Shock Response Control Using MEIDs ^|^mdash;Consideration of a Single-Axis Falling-Type Problem^|^mdash;

When a spacecraft lands, the large shock load can lead to undesirable responses, such as rebound and trip. The authors have previously discussed the problem of controlling these shock responses using momentum exchange impact dampers (MEIDs). However, the optimal design parameters of MEIDs for spacecraft landing have not yet been addressed. These parameters are crucial for MEID applications. This paper discusses the parameters of Passive-MEID (PMEID) for a single-axis falling-type problem, which is the most fundamental problem. It is found that the rebound height is proportional to the mechanical energy of the spacecraft. Thus, the optimal design parameters of the PMEID correspond to the parameters that minimize the mechanical energy. A PMEID with the optimal design parameters is called optimal PMEID in this paper. In order to improve the performance of the optimal PMEID, this paper proposes a novel MEID — HMEID (active/passive-hybrid-MEID). The HMEID combines actuators with passive elements such as contact springs. Based on the optimal design results for the MEIDs, this paper applies a stiffness control to the HMEID in order to suppress the mechanical energy further. Simulation studies reveal that the HMEID can effectively reduce the influence of shock responses. The robustness of the HMEID against the landing ground is shown. The feasibility of the HMEID is also discussed. The HMEID is superior to a PMEID, even if the actuator has a dynamics with a large electric time constant.