已知一个二自由度机器臂的关节长度，给出一个圆形轨迹，让机器臂随轨迹移动。前提是轨迹在机器臂的工作空间内。-Known length of a two degree of freedom robotic arm joints to give a circular path, so that the robotic arm to move with the trajectory. The premise is the trajectory in the workspace of the robotic arm.