Research On The Key Technology Of SCARA Robot Grasping Based On EtherCAT Communication

In recent years,the fusion of robots and vision technology has become a research hotspot in the industrial field.Visual-guided industrial robot in automatic production line to achieve the target workpiece is one of the most common applications and calibration is the key step in the visual-guided robot.Its accuracy directly affects the robot's grip accuracy.In addition,the trajectory planning of the robot and the real-time performance of the servo system cannot be ignored for the robot to complete the task.In this paper,the key technologies of visual guided SCARA robot based on EtherCAT communication is studied.The mathematical modeling of the coordinated operation of the visual guided SCARA robot grab system is carried out,including the kinematics modeling of the SCARA robot,the calibration of the tool coordinate system,the calibration of the visual camera model and the calibration between the robot and the camera.A new method based on sixth-order polynomial is proposed to solve the problem of optimal grasping trajectory of robot.The method inserts the constant velocity into the velocity curve.From the perspective of continuous smooth running of the curve,compared with the S-shaped curve through Matlab simulation software.The results show that the method studied in this paper is simple,and the velocity and acceleration curves are smoother.Aiming at the impact of the turning point of the gate trajectory on the robot,the arc transition is put forward,and the line of transition is corrected to make the transition reasonable.In view of the high real-time requirements of the servo system,through the analysis of real-time performance of EtherCAT and the experimental verification of its high real-time performance,it is determined that the communication mode between servo driver and controller in this paper is EtherCAT.In order to improve the accuracy of hand-eye calibration,a new calibration tool is proposed to used as the fifth link to calibrate the hand-eye relationship.Based on the above research,the feasibility of the trajectory planning algorithm and the hand-eye calibration algorithm is verified by experiments,and the grabbing precision can be controlled within the range of positive and negative 0.5mm.