A few setup questions related to Delta Robot v2
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2014-04-17 at 13:40 #5959AnonymousInactive
Hi, thanks for sharing the V2 delta robot as Open Hardware!
I just built one, and have a couple of setup questions..
(I have the thing moving about with the sine wave sketch, but I just attached the arms any-old-way, probably wrong..)
– the shoulder to wrist length that defaults to 18.5cm in the sketch: is that measured between the screw holes in the ‘ball joint’ piece? i.e. axle to axle? (or is it all of the arm, right to the end of the plastic?)
– not sure how servos work: is there a proper starting position that the motor should be in before attaching the biceps?
– and related to that, what orientation should the bicep be attached in? (i.e. once the motor set is in some ‘zeroed’ position, should the biceps be attached e.g. parallel to the table?)
A few random build notes that might help someone reading this:
– 20mm machine screws weren’t long enough for the shoulder/wrist axles – they sat completely flush in the hexagonal hole, nothing for the nut to grab onto. Ordered some 22m screws, which should be perfect (haven’t fitted them yet)
– 14mm machine screws are ok for the other joints (video specifies 15mm)
– the holes on some of my ‘ball joint’ parts came out just a tiny bit too big for a tight fit with the screw – will need to work out a way to fix that to stop the arms skewing (longer screws + nuts on the end, insert a thin strand of plastic to narrow the holes, or print them again a tiny bit smaller)
So in total you’ll need: apart from the printed parts of course..
– 15x 14mm (or 15mm) M3 ‘Posi Pan’ / ‘machine’ screws
– 6x 22m of the same
– 9x M3 nuts (I went for nylock ones)
– I used 3x TowerPro MG996R servos (cheap and cheerful, metal gears, digital, allegedly an ‘improved’ version for greater accuracy) – don’t know if these are any good yet..
I’ll post a photo later, it looks pretty badass in alternating white/black parts 🙂2014-04-17 at 14:46 #6454AnonymousInactive
1. elbow to wrist.
2. start the servos centered at 90 degrees, attach the arms parallel to the base.
3. Apparently many people are having that problem. I’ll have to upload a patch that makes the holes a bit smaller.2014-04-17 at 16:55 #6455AnonymousInactive
2. start the servos centered at 90 degrees
cool, and (sorry but..) how do you do that? Do hobby servos usually auto-centre on power up or do I need to send a command?
And once it’s up and running, what’s the easiest way to send the end effector to some arbitrary x,y,z position?2014-04-17 at 17:47 #6456AnonymousInactive
I’ve just updated this page with links to the software and some configuration tips. Please let me know if that doesn’t answer your questions and I’ll take care of it.2014-04-17 at 18:57 #6457AnonymousInactive
thanks, not seeing your changes tho – comparing from the Feb version of the page, all I can see is removal of the contents section and merge of parts/assembly sections? but the links/text is all the same..
is this the latest version? http://learn.marginallyclever.com/index.php?title=Delta_Robot_1_%26_2&oldid=4052014-04-17 at 19:49 #6458AnonymousInactive
When you run ik.ino the first thing it does is drive all servos to middle (90 degrees).
In the arduino serial window you can type “M114;” to get the current position of the head in XYZ coordinates.
You can type “G00 X[number] Y[number] Z[number] F[speed number];” to move the head in a straight line. G01, G1, and G0 should all work in place of G00. If you forget a number it won’t die – G0 X4 will move on a line along X, G1 Z-5 will move only up/down.
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