Design And Research On Control System Of Placing And Removing Manipulator Of Stretcher

Stretcher is used to drawing sheet metal, it has been widely used in industry ofhardware fitting, home Appliances, aluminum products of cars and stainless steelproducts. Along with stretcher’s wide application at home, the machining process ofstretcher is hoped to have a higher degree of automation. On account of automaticproduction of numerical control double-acting hydraulic stretcher, a placing andremoving manipulator of stretcher has been designed in this paper, the manipulatorcould take the place of manual work, improve the degree of accuracy of placing andremoving and enhance the production efficiency of stretcher.In this paper, first the working status of stretcher was analyzed, then completed theoverall structure design and spatial layout of the manipulator, after that the workflowaction of manipulator is analyzed. Considering that the size of workpiece is unstable,automatic centering cross connecting rod translation grippers is designed. The hydraulicsystem of manipulator is designed, which provide the action sequence table of thehydraulic system’s electromagnet and the action cycle figure of hydraulic actuator, thenanalyze the working principle of the hydraulic system. After that the type selection ofhydraulic cylinder, hydraulic motor, electro-hydraulic servo valve and hydraulic pumpis done. Finally, the performance of the hydraulic system is checked to ensure thesystem’s stable operation.In this paper, the kinematics model of manipulator is finished by using the D-Hmethod,and inverse kinematics equations is solved, finally the simulation of thekinematics and inverse kinematics is done by using the Robotics Toolbox of Matlab,then the space trajectory of the manipulator end effector and the curves of each joint’sdisplacement, velocity and acceleration is achieved. The mathematical model of theelectro-hydraulic servo position control system of the manipulator forearm isestablished, and a simulation model is established by Simulink in Matlab, for the system damping is relatively small, which leads to an unstable system, the pressure feedbackcontrol is added to the electro-hydraulic servo position control system, which greatlyimproves the system damping ratio and system stability, thereby increase the accuracyof manipulator placing.The analysis and simulation of kinematics of manipulator helps to verify therationality of the structural parameters design of the manipulator, also provide a reliablebasis for theoretical analysis on manipulator’s control system design, dynamics researchand trajectory planning. The research on forearm position control system of manipulatorshows that pressure feedback control can increase the stability of the forearm positioncontrol system and improve the accuracy of manipulator placing.