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Post by Trip Rodriguez on Sept 11, 2014 11:44:50 GMT
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Post by tronicgr on Sept 11, 2014 18:15:26 GMT
It looks good, except for the Pololu motor driver. I think it won't be strong enough for 3DOF in combination with the motors you choose. I'd suggest Sabertooth instead. Also you will need position sensors. For the DIY linear actuators you will need a multi-turn sensor. This magnetic contact-less are very low noise and reliable: AMM20B5A1CLASL380-NDThanos
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Post by Trip Rodriguez on Sept 12, 2014 5:57:38 GMT
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tino
Junior Member
Posts: 71
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Post by tino on Sept 12, 2014 22:03:17 GMT
It looks good, except for the Pololu motor driver. I think it won't be strong enough for 3DOF in combination with the motors you choose. I'd suggest Sabertooth instead. Hi Thanos, That's for 3dof? These motors are rated for 21-22A under load, and pololu driver can continuously deliver 25A, 35A with a heatsink, and 200A peak. Do you think Pololu drivers should work OK with these Chinese motors for 6dof? I plan to have cpu cooler on each of the drivers (much better cooling than on sabertooth) www.dimensionengineering.com/products/sabertooth2x60It's not much of a price difference ($45 per DOF) but I'm not sure why it's needed?
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Post by tronicgr on Sept 16, 2014 22:31:02 GMT
For 6DOF, the motors support all the weight, but the load is shared between the motors. Also you are going to use some kind of chain gear reduction if I'm not wrong that will handle the needed torque. So no problem for 6DOF.
But for 3DOF, that Trip is planning to make, the load will be higher as it will be making larger rotation angles, so even if he is using fixtures to help the motors convert the torque to linear thrust, there will be demand for large load when the platform is tilting too much as the load will disposition its COG.
Thanos
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tino
Junior Member
Posts: 71
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Post by tino on Sept 17, 2014 10:59:34 GMT
Thanks Thanos!
Yes, I'll be using 3:1 sprocket system to lower the workload so effectively the weight of the platform will be reduced by 2/3 as far as motors are concerned. 6 of these motors should be able to move 30-40kg of weight after the reduction (100-110Kg / 3) Best regards, Tino.
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edk
New Member
Posts: 2
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Post by edk on Apr 17, 2016 12:46:09 GMT
Hi Tino Is there a thread showing your sim? I'd love to see. And why did you go Polulu? The $10 43A HBridge from China on Ebay has built in logic isolation, and though I take 43 amps with a grain of salt, they can certainly handle sustained 35 amps at 24 volts. I've used them on (BIG) doors, conveyors, the power feed on my milling machine and other automation tasks, and I have never had a failure, or even a hiccup. Rock solid. I don't know why people shy away from them and go JRK or Sabertooth. You can use a 10 buck arduino or a 30 buck Pi for logic for a measly $20 or $45. I'm using Thanos' board with those H bridges on my 6dof, but on my 2 and 3 dofs I used Aduino(s) and those 43a HB's. Never skipped a beat. BTW, loved your thread re levers on that other site (that should not be named now). BSFT really is a fudge sickle head..... Cheers Ed
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Post by tronicgr on Apr 17, 2016 22:32:05 GMT
Hi Tino BTW, loved your thread re levers on that other site (that should not be named now). BSFT really is a fudge sickle head..... Cheers Ed I have no issues with the name of the site, or its members... You can name it here. And thanks, I'm not the only ones that thinks some of their members are literally trolls! Thanks Thanos
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tino
Junior Member
Posts: 71
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Post by tino on Apr 18, 2016 10:09:44 GMT
Hi Tino Is there a thread showing your sim? I'd love to see. And why did you go Polulu? The $10 43A HBridge from China on Ebay has built in logic isolation, and though I take 43 amps with a grain of salt, they can certainly handle sustained 35 amps at 24 volts. I've used them on (BIG) doors, conveyors, the power feed on my milling machine and other automation tasks, and I have never had a failure, or even a hiccup. Rock solid. I don't know why people shy away from them and go JRK or Sabertooth. You can use a 10 buck arduino or a 30 buck Pi for logic for a measly $20 or $45. I'm using Thanos' board with those H bridges on my 6dof, but on my 2 and 3 dofs I used Aduino(s) and those 43a HB's. Never skipped a beat. BTW, loved your thread re levers on that other site (that should not be named now). BSFT really is a fudge sickle head..... Cheers Ed Hi Ed, I've got a thread here, (it's been a bit quiet lately): motionsim.freeforums.net/thread/148/6dof-dc-motors-aliexpressUnfortunately I don't have a lot of free time so the progress has been slow, but steady. I'll post a small update on the thread shortly. These H bridges from ebay seem very interesting, but I'm not sure you can have the same level of quality control on 10$ vs 50$ product (with warranty). Pololu was within my budget and the whole platform will probably cost 1000-2000 euro so no point skimping on one of the most important components. There are also lots of nice people on Xsim forum, I got the motivation for my build and recommendation for motors from merchan-e, and I'd really like to have more sim software options (so I wish them all the best), but it seems that they 6dof support is still under development...
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