Investigation on design and reliability analysis of a new deployable and lockable mechanism

The traditional structure of the deployable and lockable mechanism on soft-landing gear system is complicated and unreliable. To overcome the defects, a new deployable and lockable mechanism for planetary probes is developed. The compression assembly shares a set of new mechanism with the deployment assembly and locking assembly. The new mechanism shows some advantages: more steady deployment, simpler mechanism and higher reliability. This paper presents an introduction of the deployment and locking theory of the new mechanism, and constitutes the fault tree, which would contribute to qualitative and quantitative analyses. In addition, probability importance and criticality importance of the new mechanism are derived and calculated. The reliability modeling and analysis of the mechanism are accomplished from static torque margin, torque and the work by torque. In investigation results, reliability rate that the new mechanism could deploy successfully is 0.999334. The crucial problems concentrate on the insufficiency of storage force torque of high strength spring, the lubrication failure between the inner cylinder and the outer cylinder of the strut and the stuck soft-landing gear system. And then, the paper presents some improvement approaches and suggestions according to the problems discussed above.