It is not really a perfect circle and it would never be one. One reason is the construction used so far. Right now I use screw rods, which are first unsupported and secondly not straight. To improve the resolution of the circle, I have to buy expensive hardware, like ball-screws, bearings and encoders.
I wrote the program with the sine & cosine description of a circle, and with a proportional speed controller between both axes.
Another problem is that the motors do not start simultaneously, this cause an edge in the circle.
The proportional controller isn't accurate at all; the issue is that the motor accelerates at the beginning much faster as at the end of his power-reach. It is very difficult to find a good power-speed curve.
Next picture shows the circle drawing program:
Next are both cases for the proportional controller :
Next are both cases for the motor controller:
And of course the movie:Next step is to engrave my name into wood...;)
Movie coming soon!
This is just a cool design. Wow!!
ReplyDeleteClaude Baumann