The Research And Development Of Automatic Loading And Unloading Robot For Sheet Metal Stamping

In consideration of the domestic labor environment, policy transformation and enterprise’s pressure of competition, there demands a great urgent need for automated production equipment instead of workers. At present, in some large auto companies, the robots punch line has been used widely, but many small companies are still using manual loading. This paper designs a low-cost automatic robot for small sheet metal stamping, which can achieve automatic loading and unloading functions.According to the project’s requirements and design specifications mission, the author identifies the basic technical parameters of the mechanical arm to provide the basis for the entire robot system. Propose a four-DOF manipulator by the method of analysis and comparison, Use DH method to establish the mathematical model of the manipulator and finished forward and inverse kinematics solution of the robot, as well as the manipulator Jacobian matrix. Then design the robot’s workspace based on MATLAB software and the overall structure of the robot based on Solidworks, select the robot movements joint’s motors and reducers by analyzing working conditions. The detail structure design of the movement joints are given, showing a typical joint structure detailed assembly diagram in the paper and finish virtual prototype design and assembly of the body structure of the robot. Simulate the actual working conditions based on ADAMS after writing the logic timing diagram of the robot combining with the actual work. Draw out the process in motion, the torque of each joint torque curve diagram, and the speed of the end of the mechanical arm, acceleration motion curve.Use ANSYS finite element analysis module to do structural static and dynamic analysis for the whole machine, determine the modal of the machine when the tool is at different places, determine the rotational speed of the spindle to avoid resonance, consider only gravity in this case, the tool’s static deformation in each direction of the machine in different feeding positions changes very small, which has verified the accuracy of the structural model has meet the design requirements.An error model of robot with strong versatility is proposed based on the generalized pose error vector definition of coordinate system. As the DH law can’t reflect the pose error of coordinate fully, the generalized geometric error of link coordinate system is proposed by introducing modified DH method. Then build error model of the robot designed in the project based on MATLAB. Plot the pose error curves of the end of mechanical arm by changing the size of length error and angle error to compare which influences the pose error more.