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I am working on a factory automation project, and would like to see any feasibility of object tracking on a conveyor. Currently, a worker manually picks up a bolt and screw it on the hole of an object which is flowing on a conveyor. The speed of conveyor is approximately 100 mm/s. (speed can change during operation) To automate the task using robot arm (UR, Yaskawa.. etc), first it needs to detect the object is, find the hole, and then screw the bolt along the moving object.

For each task, I was thinking to use following methods:

  1. Template Matching for detection of object.
  2. Hough Circle for finding hole. Contour might be better if houghcircle is too slow for real time tracking
  3. For tracking, use kalman filter based on the hole location calculated from 2.

The problem is, I think time for doing each image process will be too slow on a real-time tracking, and I am not sure the finding the center of a hole will be accurate enough for screwing. Maybe I should just find the hole once and track the initial coordinate based on the speed of conveyor. The speed of conveyor will be tracked by two ways, vision and encoder. (not decided yet)

What would be a better option to deal with this problem? Any advice is appreciated.

Lunethan
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  • While screwing bolt, the conveyor will stop, right? If you can share sample images, it can be more easy to guide – Yunus Temurlenk Aug 06 '20 at 04:47
  • The conveyor will not stop. The robot arm should move along and screw at the same time. Unfortunately, I haven't got the images yet. – Lunethan Aug 06 '20 at 06:51
  • Then after detection holes, the hole coordinates will change until robot reach that holes. In this kind of applications, conveyor should stop. How the way the robot will screw the bolts while conveyor moving. This is not safe anyway – Yunus Temurlenk Aug 06 '20 at 07:04
  • If I know the coordinate of the hole as well as the speed of conveyor, I can predict the coordinate of the hole when the robot touches the hole and then it can move and screw simultaneously. It is just my theory. Do you think it won't work well? – Lunethan Aug 10 '20 at 04:50
  • I am saying its not a good approach and NOT SAFE. But you may experience by yourself. You dont have a sample image, I suggest you [this post](https://stackoverflow.com/questions/59679516/opencv-edge-based-object-detection-c/59688284#59688284) for detection. I didnt see the sample image but I dont suggest houghcircle or templatematching according to experiences – Yunus Temurlenk Aug 10 '20 at 04:54
  • I considered adding an additional support machine that lifts up the object and screw along the conveyor which would give the same effect as stopping conveyor, but it wouldn't work due to the limited working space. Anyway, I'm not sure if the method you suggest will be fast enough for real time tracking. Now I'm thinking of applying Kalman filter for prediction of the coordinates of a hole to minimize the impact of image processing time. Thank you for the suggestion of the detection method. – Lunethan Aug 11 '20 at 03:28

1 Answers1

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It is recommended to use a robot kit. yaskawa: "motopick" It has integrated vision and conveyor belt.

Ruben Helsloot
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charles
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