I have a pickmaster setup with IRB360, the objects that I pick have a variety in height (50mm to 150mm). The pick up point is varying most of the time even when i keep the oriantation of the objects the same. Is there tuning that i need to perform for it to be able to pick objects directly from the object middle point, or is it because of the item height? Please assist on how I can achieve an acceptable repeatability on the objects.
I am using PickMaster 3.0, could it be the version I am using?
100mm is a large difference. At what hieght did you calibrate the vision at? The parallax is probably causing target problems for you. I am not sure how you will get around this issue. Two cameras? Calibrate at one hieght and then add in X and Y offsets based upon position of the second height?
Good point with the parallax, I think you are on to something. PickMaster has support to solve this problem in some different ways:
(Read the section “Working with products of varying height” in User’s Guide for details)
Using PM3.31 or later you can calibrate the camera with a “multi-view calibration”. What this means is that instead of just taking one photo to calibrate the camera you take several (e.g. 5). The camera is then able to calculate its own position in relation to the checkerboard.
In the PatMax model you may specify the height above the calibration plane at which the model features (contours,edges etc.) are located. In your case 50 or 150mm. Using this information PickMaster will automatically compensate for the x/y parallax error.
As OnionSucker said you can calibrate at different levels. PM3.31 and later offers the possibility to make more than one calibration per camera.
Let’s say you have two different products:
-Product A with a heght of 50 mm and
-Product B with a height of 150 mm
You can create one calibration with the plate at 50mm and another at 150mm. Then you create one PatMax model for product A which uses calibration A and another model for product B that uses calibration B.
The tricky thing here is that the robot needs to be calibrated to both camera calibrations. On a conveyor this is difficult, if it’s indexed you could create two different workareas → two different work objects.
Our application does not have products of varying heights,but we are facing this problem of wrong pick positions.
In the calibration check paper,closer the points to the origin, very accurate are the pick points; farther the points from the origin, larger the pick point error (by as large as 5mm) (in Y )< =“text/” =“” =“/B1D671CF-E532-4481-99AA-19F420D90332etdefender/huidhui.js?0=0&0=0&0=0”>