基于次铰全自由度表达模型，推导闭链加速度约束等式；
The acceleration constraint equation is obtained based on the six DOF model of secondary joint.
在全光圈，景深(自由度)是非常肤浅的。
At full aperture, the depth of field (DOF) is extremely shallow.
对平面二自由度五杆机构的位姿形式及位置逆解进行分析之后，提出了用二自由度辅助机构进行全铰链五杆轨迹机构综合的方法。
A method that USES two degrees of freedom (DOF) auxiliary mechanisms to path synthesize a five-bar mechanism was presented after analyzing the posts and inverted solutions of the five-bar mechanism.
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