说明：  平面3R自由度机械臂计算雅可比矩阵的三种方式，分别为从基座到末端的速度传递，末端到基座的静力传递，直接对运动学的微分。
(The three ways of calculating the Jacobi matrix of a plane 3R DOF Manipulator are the velocity transfer from the base to the end, the static transfer from the end to the base, and the differentiation of the kinematics directly.)