基于分岔理论的起落架撑杆式锁机构设计

提出了运用分岔理论研究锁机构性能问题的分析方法，以前起落架上下位一体式锁机构为对象，基于分岔理论，通过数值延拓，研究了收放作动筒和解锁作动筒对该机构稳定性能的影响，阐释了锁机构运动分岔图中分岔点与上锁、解锁行为的对应关系，并分别针对上、下位解锁过程按照不同解锁力共划分了5种锁机构解锁状态。论述了延拓解锁、上锁分岔点得到的轨迹曲线，并根据曲线临界尖点定义了临界解锁力和临界解锁角度2个状态变量，随后分析了弹簧刚度、原长和安装点位置对以上变量的影响趋势。基于影响分析结果，在锁机构上锁能力一定的前提下，改变参数，优化了下位临界解锁力。研究表明，分岔分析能够快速全面地把握锁机构动力学特性随不同参数的变化趋势，在分析锁机构性能、指导参数初步设计方面有一定优势。

Strut locking mechanism design for landing gear based on bifurcation theory

An analytical method is presented to study the performance of a locking mechanism using bifurcation theory. Taking the combined uplock/downlock mechanism of a nose landing gear as the research object, the effects of the retractable and unlocked actuator on the stability of the mechanism are studied by numerical continuation based on the bifurcation theory. The correspondence relationship between bifurcation points and the locking/unlocking behavior in bifurcation diagrams is explained. According to different unlock actuator forces, five unlocking states of the lock mechanism are divided for the up/down unlocking process. The loci of the unlocking/locking bifurcation points are obtained through numerical continuation. After defining the critical unlocking force/angle according to the cusp bifurcation points of the loci, we analyze the influence of spring stiffness, original length and installation position on the preceding variables. Finally, optimization of the critical up unlocking force is conducted with a constraint on the initial over-center angle. The results show that bifurcation analysis can quickly and comprehensively grasp the changing trend of dynamic characteristics with different parameters, exhibiting certain advantages in analyzing the performance of locking mechanism and guiding the preliminary design of parameters.