SYSTEM AND METHOD FOR AUTOMATIC VEHICLE BODY SANDING

Abstract

An automatic vehicle body sanding system operated in a painting factory includes a painting inspection device configured to detect a defective position (NG Point) by analyzing a 2D image of a vehicle body for which an intermediate process has been completed taken with a camera, and display the defective position on a 3D vehicle body drawing. The automatic vehicle body sanding system includes a robot having a multi-joint structure on which at least one of a 3D scanner, a sanding tool, and a dust absorber required for sanding work is mounted. Further, the automatic vehicle body sanding system includes a server configured to match the defective position of the vehicle body detected by the painting inspection device and 3D scan data of the vehicle body scanned by the 3D scanner with a 3D vehicle body drawing shape on a simulator.

Description

Claims

1. An automatic vehicle body sanding system operated in a painting factory, the automatic vehicle body sanding system comprising: a painting inspection device configured to detect a defective position (NG Point) by analyzing a two-dimensional (2D) image of a vehicle body for which an intermediate process has been completed taken with a camera, and display the defective position on a three-dimensional (3D) vehicle body drawing;a robot having a multi-joint structure on which at least one of a 3D scanner, a sanding tool, or a dust absorber for sanding work is mounted; anda server configured to match the defective position of the vehicle body detected by the painting inspection device and 3D scan data of the vehicle body scanned by the 3D scanner with a 3D vehicle body drawing shape on a simulator, and control the sanding work of the robot by creating a 3D robot path so that a sandpaper of the sanding tool contacts with a surface of the defective position horizontally.

2. The automatic vehicle body sanding system of claim 1, wherein: the painting inspection device is configured to process the 2D image according to a painting inspection algorithm to identify the defective position and a defect type in a predetermined area.

3. The automatic vehicle body sanding system of claim 1, wherein: the robot is configured to scan a plurality of feature points designated on the vehicle body while moving the 3D scanner according to an applied control signal.

4. The automatic vehicle body sanding system of claim 1, wherein: the 3D scan data includes a plurality of 3D scan reference coordinates obtained by scanning according to a number of designated feature points.

5. The automatic vehicle body sanding system of claim 1, wherein: the robot is configured to perform the sanding work for moving the sanding tool to the defective position of the vehicle body according to an applied control signal and pressing and polishing a surface of the vehicle body by the sandpaper of the sanding tool electrically rotating.

6. The automatic vehicle body sanding system of claim 1, wherein: the robot is operable to control force pressing a surface of the vehicle body during the sanding work, and configured to measure multi-axial force and torque through a Force Torque (F/T) sensor and transmit them to the server for the force control.

7. The automatic vehicle body sanding system of claim 1, wherein: the sanding tool is configured to mount the sandpaper rotatably on a spindle and adjust sanding revolutions per minute (RPM) of the sandpaper during operation.

8. The automatic vehicle body sanding system of claim 1, wherein: the dust absorber is configured to suck dust generated during the sanding work through a suction tube and deliver the dust to an external dust collector.

9. The automatic vehicle body sanding system of claim 1, wherein: the dust absorber is formed in a dome structure surrounding the sanding tool to suppress dust scattered inside the dome structure from leaking to the outside during the sanding work.

10. The automatic vehicle body sanding system of claim 1, further comprising: a sandpaper replacement device comprising a sandpaper recovery machine and a sandpaper supply machine,wherein the robot is configured to replace an aged sandpaper with a new sandpaper by positioning the sanding tool at a home position of the sandpaper recovery machine and the sandpaper supply machine at a time for replacement of the sandpaper.

11. The automatic vehicle body sanding system of claim 10, wherein: the sandpaper recovery machine comprises: a cylinder on which the aged sandpaper is seated;a limit switch configured to check the seating of the sandpaper;a vision sensor configured to check a home position state of the sanding tool;a gripper configured to grip the seated sandpaper from both sides; anda recovery box configured to collect the sandpaper released from the grip by the gripper and freely falling after the sandpaper gripped by the gripper is removed from the sanding tool by retraction of the cylinder.

12. The automatic vehicle body sanding system of claim 10, wherein: the sandpaper supply machine comprises: a cylindrical housing including a suspension rod vertically fixed therein;a suspension plate configured to load the new sandpaper on its upper surface while being penetrated by the suspension rod;a proximity sensor installed at a predetermined supply position and configured to detect a sandpaper positioned on the uppermost layer of the suspension plate; anda linear actuator installed to be able to move the suspension plate up and down to raise the suspension plate to a position detected by the proximity sensor when supplying the sandpaper.

13. The automatic vehicle body sanding system of claim 1, wherein: the server comprises: an external interface unit comprising wire/wireless communication means for communication with a surrounding equipment;a scan processing unit configured to create a first matched image obtained by correcting a position error of the vehicle body by matching the 3D scan data with the 3D vehicle body drawing shape on the simulator;a robot teaching unit configured to match the 3D vehicle body drawing to the first matched image and process the first matched image into a second matched image on which a defective position of the vehicle body is displayed;a database configured to store various programs and data for automatic vehicle body sanding control; anda controller configured to control the sanding work of the robot in a normal direction in consideration of a surface angle of the defective position through the 3D robot path.

14. The automatic vehicle body sanding system of claim 13, wherein: the scan processing unit is configured to transform 3D scan reference coordinates corresponding to a feature point of the 3D scan data into reference coordinates based on the sanding system applied to the 3D vehicle body drawing shape.

15. The automatic vehicle body sanding system of claim 13, wherein: the robot teaching unit is configured to transform 3D coordinates corresponding to the defective position into reference coordinates of the sanding system to identify the defective position on the second matched image.

16. The automatic vehicle body sanding system of claim 13, wherein: the controller is configured to adjust pressure applied by the sanding tool and sanding RPM of the sanding tool using the robot according to a defect type or defect level of the defective position during the sanding work, and replace the sandpaper with a sandpaper of a predetermined roughness.

17. A method of automatically sanding a vehicle body by an automatic vehicle body sanding system, wherein the vehicle body is transferred through a painting inspection of an intermediate process, the method comprising: a) acquiring three-dimensional (3D) scan data by scanning a plurality of feature points designated on the vehicle body through a 3D scanner mounted on a robot;b) creating a first matched image in which a position error of the vehicle body is corrected by matching a 3D vehicle body drawing shape on a simulator to the 3D scan data;c) matching a 3D vehicle body drawing received as a result of painting inspection of a preceding process to the first matched image to process the first matched image into a second matched image on which a defective position of the vehicle is displayed; andd) controlling sanding work by creating a 3D robot path so that a lower surface of a sandpaper of a sanding tool mounted on the robot enters horizontally and proceeds in a normal direction with respect to a surface of the defective position.

18. The method of automatic vehicle body sanding of claim 17, wherein: operation b) comprises transforming 3D scan reference coordinates of the 3D scan data into reference coordinates based on the sanding system applied to the 3D vehicle body drawing shape when creating the first matched image, andoperation c) comprises transforming 3D coordinates corresponding to the defective position into reference coordinates of the sanding system when processing the second matched image to identify the defective position on the second matched image.

19. The method of automatic vehicle body sanding of claim 17, wherein: operation d) comprises performing control to adjust at least one of roughness of the sandpaper for each defect type, sanding RPM, and pressure applied by the sanding tool through force control during the sanding work.

20. The method of automatic vehicle body sanding of claim 17, further comprising: after operation d), counting operation time of the sanding tool during the sanding work to determine whether accumulated time of actually performing the sanding work from a time of replacement with a current sandpaper exceeds a threshold value; andwhen the accumulated time exceeds the threshold value, determining replacement time and sequentially positioning the sanding tool at predetermined positions of a sandpaper recovery machine and a sandpaper supply machine through the robot to remove an aged sandpaper and automatically replace with a new sandpaper.