For decades, although the inverse kinematics (IK) problem of six degrees of freedom (DOF) manipulator with general geometry has been solved, there is still needed an efficient and unified method to derive the IK formulas for the six-DOF manipulator with simple geometry. In this paper, we propose an improved method of disconnection and re-connection to achieve this purpose. Firstly, we determined the position selection of the two cutting points and the attitude setting at the first cutting point. Next, we gave the new conditions for the re-connection of the two sub-chains and the corresponding equations. Then, we summarized five methods of cutting the manipulator into two three-DOF sub-chains and corresponding equation deformations, as well as the selection principles of equation deformations. Finally, we used three examples to demonstrate the effectiveness of the method. The results show that the expressions of six joint variables can be derived from only six equations. The solutions of the wrist joint variables are not affected by the singularity.

几十年来，尽管已经解决了具有一般几何形状的六自由度（DOF）机械臂的逆运动学（IK）问题，但仍需要一种有效且统一的方法来推导具有简单几何形状的六自由度机械臂的IK公式。 。在本文中，我们提出了一种改进的断开和重新连接方法来实现此目的。首先，我们确定两个切割点的位置选择以及第一个切割点的姿态设置。接下来，我们给出了重新连接两个子链的新条件和相应的方程式。然后，我们总结了将机械臂切成两个三自由度子链和相应方程变形的五种方法，以及方程变形的选择原理。最后，我们用三个例子证明了该方法的有效性。结果表明，仅可以从六个方程式导出六个联合变量的表达式。腕关节变量的解不受奇异性的影响。