The human moving system is defined as a rigid frame, which contains 19 articulate entities. Entity rotates around the father node and its son node is the father of another entity at the next level.

将人体运动系统视为一由19个实体构成的刚性框架系统，每一实体上的父结点绕与上级实体连接的关节点旋转，该实体另一端的子结点则作为下一级实体的父结点。

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