Algodoo

Have you figured out what causes the runout? Is it a fault of the not-so-perfect placement of the axel on the circle/polygon? Can a person get less runout by either manually placing the axel, or by using the grid system to place the axel? Just curious what you found out.

Q: Have you figured out what causes the runout?
A: Not exactly. It looks like the circle is limited by the accuracy of the calculations. The peak-to-peak variation is smaller at sim.frequency = 120 Hz than at 60 Hz. The resolution of the circle plot is 0.06 microns.

Q: Is it a fault of the not-so-perfect placement of the axel on the circle/polygon?
A: No, I edited the file for perfect hinge position and it did not change anything.

Q: Can a person get less runout by either manually placing the axel, or by using the grid system to place the axel?
A: No, I don't think so.

The runout on the polygon is because it is made of 128 line segments. If you make the circle and polygon reflective, then you can see that the laser beam reflected from the circle is steady while the beam reflected from the polygon dances around slightly. You can count the 128 cycles per revolution on the polygon runout chart.

P.S. I calculated the difference in distance to a flat vs. distance to a vertex on the 0.5 meter diameter polygon of 128 sides and the result is 75 microns, which is close to what is showing on the chart.

That's very interesting. I believe there's a variable (I think it's called maxLineSegments or something like that) which you can adjust in the console for the maximum number of line segments (vertices) that make up polygons. I wonder if increasing that number will reduce the runout.

Thanks for the info!