Dynomotion Forum

In a large gantry machine measuring 10 meters in width, I conducted a pen trace and obtained the results depicted in the accompanying images. When I drew a circle in a clockwise direction, the resulting shape appeared as an oval, with the longer diameter rotated approximately 45 degrees clockwise, as shown in picture 1. Conversely, when I executed the same movement in a counterclockwise direction (picture 2), the longer diameter of the oval was rotated 45 degrees counterclockwise. I did not observe any backlash in either the X or Y axes. The Y axis is equipped with two motors configured in a master/slave arrangement. I attempted to misalign the two motors by a maximum of 30 millimeters; however, due to the rigidity of the gantry, further misalignment was not feasible, and there was no significant alteration in the circular or oval traces.
When i did the same pen trace with a bigger circle, (diameter 300mm) the error was about the same 305 mm in the long oval axis and 299 in the small.
Al the three motors are analog servos . What else should i check?
Regards.

Are the axes tuned well to have small following errors? Set the Max following error to the equivalent of 1mm and see if you get an error.

The following error was very big, when i decreased to 10mm (500, the cnts/mm is 50) i had an following error on ch0 the master/slave are ch0/ch1.

That would indicate the axes are not following well. Check the servo tuning using the KMotion Step Response Screen.