Re: Arm length calculation help on own-design delta needed January 06, 2016 06:49PM |
Registered: 10 years ago Posts: 14,684 |
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hercek
... but for a delta calibration to be really easy somebody needs to derive and publish a calibration procedure for tilted towers.
Re: Arm length calculation help on own-design delta needed January 07, 2016 01:00AM |
Registered: 13 years ago Posts: 300 |
Re: Arm length calculation help on own-design delta needed January 07, 2016 01:02AM |
Registered: 13 years ago Posts: 300 |
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fma
With tilted towers, it seems that arms remains more // to the towers in every point (didin't check with maths), so accuracy should not change as much as with vertical tower, from center to edge of bed.
Re: Arm length calculation help on own-design delta needed January 07, 2016 03:03PM |
Registered: 11 years ago Posts: 732 |
I know. I briefly looked at it. If somebody is interested in details it is posted somewhere in the google delta group. I stopped to follow it since its traffic is too big and the best ideas are posted here too.Quote
dc42
To handle tilted towers properly would require an extra 6 calibration parameters, as each tower can tilt in 2 directions. The delta maths would be more complicated. An absolute minimum of 12 probe points would be needed, and more in practice. If we compensate for tilted towers, then IMO we really ought to compensate for other common build errors such as non-parallel rods, rods not all being of the same length, and bearing lines not being at 120 degree intervals on both the carriages and the effector. That makes another 10 or more parameters to calibrate, and correspondingly more probe points would be needed.
Re: Arm length calculation help on own-design delta needed January 07, 2016 03:19PM |
Registered: 10 years ago Posts: 14,684 |
Re: Arm length calculation help on own-design delta needed January 08, 2016 12:49AM |
Registered: 13 years ago Posts: 300 |
Re: Arm length calculation help on own-design delta needed January 08, 2016 04:49AM |
Registered: 11 years ago Posts: 732 |
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dc42
Did you work out a solution for the forward kinetics too?
Re: Arm length calculation help on own-design delta needed January 08, 2016 04:59AM |
Registered: 11 years ago Posts: 732 |
No there is only z-error notebook showing charts for towers which are still perpendicular: [github.com]Quote
fma
Are there curves, somewhere, showing the resulting errors on the movements, depending on the different errors that can be encounters, as described above (for standard vertical towers, not titlted ones)? I've no idea of the order of magnitude of all this...
Re: Arm length calculation help on own-design delta needed January 08, 2016 05:10AM |
Registered: 13 years ago Posts: 300 |
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hercek
That seems to be what people seem to call forward for reasons I newer understood. Why it should be called forward when the direction we primarily need is the other one?