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OpenScan-org / OpenScan2

an improved firmware for the OpenScan devices, featuring many more cameras and a greatly improved overall usability
GNU General Public License v3.0
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Issue: Turntable, turning in random directions #23

Closed OpenScanFan closed 2 years ago

OpenScanFan commented 2 years ago

Hey, hope someone can help with this one When scanning, the turntable does not turn in equal distances, it just jumps all over the show Any reason for this?

Sample alignment results showing camera positions Turntable_Issue

OpenScanFan commented 2 years ago

Can someone please address this issue? its pretty serious for me @OpenScanEu or Tomasz? Anyone?

These are the default settings that I am using, anything wrong? Motor_Settings

sokol07 commented 2 years ago

I briefly looked through the positions generator in code and I don't see an issue there. Are you sure that the software you're using are drawing this schematic precisely? Maybe it's just a matter of the software ability to detect the position? Maybe I'll have some more time in the evening, I'll try to investigate the code generator further.

OpenScanFan commented 2 years ago

Yes, I am sure the software I am using for reconstruction is calculating camera positions precisely. I can physically see the motor rotating in random positions on the scanner.

Do you think it could be the voltage setting on the stepper motor driver on the board may be set incorrectly?

Yes please, if you can check it that would be great. thanks

sokol07 commented 2 years ago

I don't think so - even if the voltage (or rather - current) is set incorrectly a step is a step, I doubt that the stepper is missing steps unless you're scanning extremely heavy and it doesn't have enough power to move. That's a stupid idea but I made that mistake and realised it after definitely too long time (please, don't laugh at me) - do you have a correct version of the OpenScan set in the setting? OpenScan Classic with Mini in setting is doing really strange things, I guess in the opposite way it is the same. image

Further thing to check are the stepper parameters - at the default ones my steppers weren't working correctly. Check if the 90 degree rotation (manually by step) is really 90 degree - maybe there is something wrong with the steps/rev settting.

In my case I had the steps/rev for the turntable set to 3600 while the correct value is 3200: the stepper has got 200 steps/rev so using the microsteps the next values are (depending on microstepping): 400, 800, 1600, 3200. The rotor stepper in my case (again, that's for the OS Classic, it may be different for mini) was set for 17067 and that's correct, because the gear ration is 64:12 so 3200*5,(3)=17066,56...

yoyo42 commented 2 years ago

I had noticed this but I assumed it was an algorithm that covered more angles in fewer images. Seems to work OK anyway.

OpenScanEu commented 2 years ago

@sokol07 @OpenScanFan @yoyo42 In fact, there was an error with the steps per revolution of the turntable (I set the value to 3600 instead of 3200) resulting in that weird pattern. And yes, the 'random' movement is totally intentional. I have used a golden spiral to equally space the images around the globe. See this reddit post for some more details.

OpenScanEu commented 2 years ago

@OpenScanFan image Here you can see a comparison of the two approaches (turntable vs optimized).

OpenScanFan commented 2 years ago

yeah, I changed the value from 3600 to 3200 and seems to have fixed the problem