uArm Swift Pro / Z-level consistency

Hi, I’m trying to use a Swift Pro as a drawing arm, with a pen held in the universal adapter.

I’ve written a script that interpolates between three points along a curve, at random positions within boundaries of the arm’s coordinate system. I’m using this library: GitHub - uArm-Developer/uArm-Python-SDK: New python library for Swift, Swift Pro

The biggest problem I’ve having right now is the inconsistent height (z-level) of the arm. I am only addressing the x and y properties like so:

swift.set_position(x = y_new[i], y = x_new[i], relative = False, wait = True);

I attached a time-of-flight sensor (1mm precision, ~3mm standard deviation) to the universal adapter, and I have it reading actual z values every 10ms, tracking the difference over time. I usually get around 23mm in difference, which is significant when trying to use it to draw (with a pen attached).

Here’s a video of it in action:

Any ideas on how I can further narrow this problem down / troubleshoot / fix this?

Hi Nick,
Please try to refer to the guide to calibrate the uArm

Thanks, but where can I get the calibration sheet to print out?

Hi Nick, there is a calibration paper come with the unit in the box. Could you please check the original box of the product. Or you can download it from here :

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Perfect, I found it in the box. Thanks for the supplying the download link, that’s useful if it gets lost.

I ran through all the steps and now it’s running much better!

Wow, that’s great.:grinning: