RugBot 1000

Hypot is a HAL Realtime component. I use it to get the velocity of the combined movement of the X and Y axis and use it to control the velocity of the needle motor. The result is that I am able to get perfectly consistent stitch length regardless of the speed or direction. When the velocity drops for turns, the velocity of the needle matches the speed and perfect spacing.

I have attached my files which may or may not help. The needle is listed as axis "U" and is run by stepgen.6 in a velocity mode using step and direction to a DMM servo . There are some other things happening like rotating the mechanism with axis A and some other specialized stuff which I can describe if needed.

great teacher.
yes I understand.
I was thinking about using one of the following options.
1) use a dc motor for the needle and using hypot to send a pwm signal to vary the speed proportional to the hypot speed. but would you do to get this pwm signal from hypot ??
2) Use an ac motor and a vfd frequency variator. and use the 0-10 signal to control rpm proportional to hypot ... I think it's the same as the previous one because it would be equivalent to using pwm ..

a question:
How do you control the table xy . only move the table when the needle is up. to avoid breaking needle.
I do not have a servomotor for now. they are very expensive.
but I find it interesting.

You are a genius .. I would like to achieve it and share it with you.

maybe recommend me a manual or book to learn to program linuxcnc. Im new in this.

I use a sub-routine at the end of the move. I will try to get some files off my controller to show you the code. Basically at the end of the move the gcode calls a subroutine that moves the needle motor until it lines up with a sensor which corresponds to the up position, and then pauses. Currently I then manually move the head back along what would be the Z axis, cut the yarn, press "S" on the keyboard which starts the program and moves to the start of the next move, and pauses. I then move the head back into contact where it is held by an air cylinder which acts as a constant force spring. I then hit "S" again to restart the program and it continues on its way. For my needs I cruise at 240 stitches/ 1080mm per minute which is slow enough for me to react to jams and whatnot.

I feel confident that you can use the velocity output of Hypot run PMW or +/- voltage but I don't know the details. Linuxcnc is very rich in features and there is documentation on this website but not any "manuals" that I am aware of. This forum and its users are the best resource but you have to figure out what to ask.

Also if you give a description of what you are trying to do it helps out a lot. The vast majority of CNC users are controlling wood and metal working machinery so you have to be creative in figuring out the useful similarities.

Badger wrote: Linuxcnc is very rich in features and there is documentation on this website but not any "manuals" that I am aware of. This forum and its users are the best resource but you have to figure out what to ask..

The documentation (manuals) for Linuxcnc can be found here.
linuxcnc.org/docs/

Just went to point some one at this and saw the video on youtube has died ..... would be good if we could see the rugbot in action

Badger wrote: I have been working on my rugbot for a few years now and it is finally up and running. Like many projects there is room for improvements. Many thanks to the kind folks here for their help. When I started I knew nothing about CNC and figured that open source was the only way to go. The key things I found were using Inkscape and gcodetools tangent knife to create the paths, then using "hypot" of only the X & Y axis to input a velocity command to drive the needle keeps even spacing at any speed. Thanks and I hope you find the video entertaining