Research On Bearing Assembly Workbench Based On Digital Twin

Bearing is one of the important parts in machinery manufacturing equipment,which is assembled by inner ring,outer ring,rolling body and cage.The digital twin is an important means of data interaction between the physical world and the digital world,and it is one of the effective methods for intelligent bearing assembly.In order to improve the bearing assembly efficiency and production safety,in view of the practical engineering problems such as low assembly accuracy and difficult on-site debugging during the rolling bearing assembly process,the research on the bearing assembly workbench based on digital twin is carried out.The main research contents are as follows.First,through the modular design method,the mechanical system and control system design of the rolling bearing automatic assembly table were completed.The assembly workbench mainly included a robot module,an assembly module,a pneumatic module and a human-computer interaction module.The structural design of the inner and outer ring fixing module,the bead filling module and the bead separation module were carried out,and the mechanical analysis of the bead separation process was completed,and the overall control of the assembly workbench was realized based on PLC.Secondly,a digital twin model of the assembly robot,end effector,automatic assembly fixture,etc.in the rolling bearing assembly workbench were established based on Visual One.The D-H parameters of each connecting rod of the assembly robot were determined,and the forward and inverse kinematics were analyzed to provided the basis for the change of the action pose of the robot digital twin model.The action development of the bearing assembly workbench was completed based on the Python script.The virtual debugging of the digital twin model of the bearing assembly workbench based on PLC verified the rationality of the PLC logic and reduced the difficulty of on-site debugging.Based on the OPC unified architecture,the mapping relationship between the physical entity of the bearing assembly workbench and the digital twin model was completed,and the information interaction between the physical model of the bearing assembly workbench and the digital twin model was realized.Experiments show that when the assembly robot moved,the motion trajectory of the virtual end digital twin model can been mapped in real time.Finally,during the bearing assembly process,the trajectory planned of the robot’s grasping and placing of the workpiece was carried out,and the robot parameters were constrained by the teach pendant to determined the key value points of the robot’s motion.Used the quintic B-spline curve,the trajectory planned of the robot joint space was carried out to ensure the efficient and stable movement of the robot.In this paper,the physical model and digital twin model of the bearing assembly workbench are constructed,and the data communication between the digital twin model of the bearing assembly workbench and the physical workbench is established.The virtual and real collaborative operation between the digital twin model and the physical entity is realized,and the motion trajectory of the assembly robot is planned,which provides reference for the application of the digital twin technology in the field of bearing assembly.