A dual-sidestay landing gear is prone to locking failure in the deployed state due to the restriction of movement between two sidestays. However, the principle of its locking movement still remains unclear. The present study is aimed at investigating the synchronous locking performance of the dual-sidestay landing gear based on the singularity and bifurcation theory. From the perspective of the kinematic mechanism, the reason for high sensitivity to structural dimensions in the locking process is explained, and the locked position is investigated by employing the numerical continuation method in the case of a single-sidestay landing gear. Afterwards, the reason for the locking failure of the dual-sidestay landing gear is analyzed, and a kinematic optimization method for the synchronous locking is proposed. The results reveal that the lock links must reach the lower overcenter singular point to fully lock the landing gear, and the singular point is sensitively affected by structural parameters. Owing to the different positions of singular points, the movements of fore and aft sidestays seriously restrict each other, causing locking failure of the dual-sidestay landing gear. The singular points of two sidestays can be optimized to be approximately identical, making their movements more coordinated.

中文翻译：

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侧撑起落架锁定机构的运动奇异性和分岔分析

双侧撑起落架由于两个侧撑之间的运动受限，在展开状态下容易发生锁定失效。然而，其锁定运动的原理仍不清楚。本研究旨在基于奇异分叉理论研究双侧撑起落架的同步锁定性能。从运动机构的角度解释了锁定过程中结构尺寸敏感性高的原因，并在单侧撑起落架的情况下采用数值延拓方法研究了锁定位置。随后，分析了双侧撑起落架锁定失败的原因，提出了一种同步锁定的运动学优化方法。结果表明，锁定连杆必须到达下偏心奇异点才能完全锁定起落架，并且奇异点受结构参数的影响很敏感。由于奇异点位置不同，前、后侧撑杆的运动相互严重制约，导致双侧撑起落架锁定失效。可以优化两个侧撑的奇异点近似相同，使它们的动作更加协调。