目的 为了提升金属拉伸工作的效率和安全性，适应人们对拉伸产品不断提升的高要求。方法 根据拉伸机的结构和工作流程设计具有四自由度的拉伸机专用上下料机械手，运用D-H法构建机械手的运动学关系式，并进行运动关系的计算。最后，采用Matlab软件中的Robotics Toolbox工具箱来建立机械手的结构模型，以及仿真机械手的工作运动状态。结果 模拟机械手的运动，得出各关节的姿态和末端执行器的行径轨迹，分析得出3个关节速度与角速度在初始与结尾处为0，且连续光滑。结论 根据仿真结果可知，所设计的机械手运动符合加工实际，可以顺利完成上下料的工作。

The work aims to improve the efficiency and safety of metal stretching work, and adapt to people's high requirements for the continuous improvement of tensile products. According to the structure and workflow of the stretcher, the loading and unloading manipulator special for the stretcher with four degrees of freedom was designed. The kinematic relation of the manipulator was constructed in D-H method and calculated. Finally, the structural model of manipulator was established with the Robotics Toolbox in Matlab, and the operating movement state of the manipulator was simulated. Through the simulation of manipulator movement, the posture of each joint and the trajectory of end actuator were obtained. The analysis showed that the three joint velocities and angular velocities were zero at the beginning and end and continuously smooth. According to the simulation results, the movement of the designed manipulator conforms to the actual processing and can smoothly complete the loading and unloading work.