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Post by hexpod on Oct 8, 2016 12:50:15 GMT
What kind of mini servo motor type would be the most suitable for analog closed - loop mode?? (with position sensors)
@ Tronic, I saw you had already used such configuration.
I am searching for a motor reference.
Thanx
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Post by tronicgr on Oct 8, 2016 15:30:33 GMT
The RC servos are similar to the big AC servo motors, just use pulse width for the positioning signal.
The Analog servos (AC servos) use an analog voltage reference for the position which is in the range -11v to +11v (with 0v being center). These AC servos have their own position closed loop control with encoders so you don't need position reference back to the AMC1280USB, so they work exactly like the tiny RC servos.
I have added this analog servo control mode as request from several people using these servomotors lately.
Thanks Thanos
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Post by hexpod on Oct 8, 2016 21:59:06 GMT
The RC servos are similar to the big AC servo motors, just use pulse width for the positioning signal. The Analog servos (AC servos) use an analog voltage reference for the position which is in the range -11v to +11v (with 0v being center). These AC servos have their own position closed loop control with encoders so you don't need position reference back to the AMC1280USB, so they work exactly like the tiny RC servos. I have added this analog servo control mode as request from several people using these servomotors lately. Thanks Thanos Thanks for the reply!
Sorry, I didn't formulate precisely enough my question.
In order to be able to simulate precisely the geometrical movements with a small scale model, I would need to build a small scale test platform as close as possible to my real scale setup. (TEKNIC DC motors plugged into AMC without extension board with 5V analog sensors)
The solution with pololu controller and HS - 311 mini motors plugged into AMC is not accurate enough for that purpose.
Question
Using the following solution.....
www.youtube.com/watch?v=Y_P1tg8yXgA
......may I use those mini motors directly plugged into AMC, or do I need necessarily the additional "extension shields" board??
and how about this stuff?:
www.pololu.com/product/2372
can it be adapted with the AMC?
I have the impression that alimented from usb3 it should be ok with a payload up to 2 kg.
I would need a confirmation.
Cheers - I.
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Post by tronicgr on Oct 9, 2016 14:17:08 GMT
I used before those micrometal DC motors directly powered from the amc1280usb (usb power)... youtu.be/TO670X46seEI don't know if the USB can handle six of them, the power has to go through the regulator of the amc1280usb that has maximum of around 800mA before the voltage drops. You can connect an external 5v 2A power supply to power the motors, the small 1A 6dof DC motor shield I created can be powered from external power supply, and can deliver combined up to 6A. motionsim.freeforums.net/thread/143/new-extension-shields-amc1280usbYou will need the 6dof DC motor shield as it converts the PWM signals to current for the DC motors. You cannot drive DC motors directly from the microcontroller pins, you will burn them. Also the micrometal gear motors have only one axle output, it might be hard to interface both position sensor and arm on them at the same time, thus the reason I got six of the little bigger white DC motors with double output gearbox. Thanks Thanos
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Post by hexpod on Oct 9, 2016 21:45:14 GMT
"You can connect an external 5v 2A power supply to power the motors, the small 1A 6dof DC motor shield I created can be powered from external power supply, and can deliver combined up to 6A." Thanks, its more clear now.
In case of using external power, one has to consider 1A per motor "rated current" or max current "stall"??
cheers - I.
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Post by tronicgr on Oct 9, 2016 22:48:06 GMT
"You can connect an external 5v 2A power supply to power the motors, the small 1A 6dof DC motor shield I created can be powered from external power supply, and can deliver combined up to 6A." Thanks, its more clear now.
In case of using external power, one has to consider 1A per motor "rated current" or max current "stall"??
cheers - I.
1A per motor is the "stall" current. The motor driver shield can handle max 2A (peak current) per motor. Usually these micro motors draw between 60mA to 100mA unloaded, but as you load them the draw more current. If you fast reverse the motor for example, even without load on it the inertial friction from the gearbox can stall the motor creating a peak current. In short for well calculated loads you can run all 6 motors from a small 2A or 3A power supply given that you don't want to stress them or the gearboxes with too much load. For a scale model this is not a problem as the load on top of the platform can be a light cockpit outline or even a fully 3D printed cockpit that still will weigh no more than 100 grams perhaps. I 3D printed a cockpit for my scale model that weighs only 30 grams for 100x100x50mm size detailed cockpit of a Bell Helicopter cockpit with two seats. I' plan to get a blog entry for it as soon as I short out the STL files. Thanks Thanos
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Post by hexpod on Oct 10, 2016 13:16:49 GMT
What is the max possible voltage coming from the "shield board" when extra powered? Would it be possible to deliver 12V?
cheers I
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Post by tronicgr on Oct 10, 2016 16:59:54 GMT
What is the max possible voltage coming from the "shield board" when extra powered? Would it be possible to deliver 12V?
cheers I The h-bridge chips can work up to 12v, so you can feed 12v to them, if you have 12v 1A rated motors. Thanks Thanos
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Post by hexpod on Oct 10, 2016 20:54:15 GMT
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Post by tronicgr on Oct 11, 2016 2:23:33 GMT
These gearmotors are great. Just make sure you don't load them over their rating to keep them in the 200mA range. I would prefer to get a 10A like this, as they are more reliable: www.amazon.com/gp/aw/d/B016895YF2?psc=1I think I'll have to add extra thicker wires to each driver for your board if you plan to use the above motors. The main connector for the external power supply is rated for less than 3A.
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Post by lzmarlop on Nov 22, 2016 22:32:22 GMT
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Post by tronicgr on Nov 24, 2016 4:22:54 GMT
Yes, these motors would work fine. But you would need to couple position sensor to them also.
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Post by lzmarlop on Dec 12, 2016 21:19:23 GMT
tronicgr Wanting to do my small model with motors smaller than 37mm, can I use those pololu micro metal motor? www.pololu.com/product/3046 ----> 12V, 0.8A @stall, 32rpm, 125 oz-in (0.88 n-m) OR www.pololu.com/product/2372 ----> 6V, 0.7A @stall, 22rpm, 80 oz-in (0.56 n-m) I wonder if I can use these motors for a 6dof model, and if it'll be better 12v or 6v.. the size would be perfect for a almost 1:10 model Thanks, Gabriel.
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Post by tronicgr on Dec 22, 2016 18:52:08 GMT
tronicgr Wanting to do my small model with motors smaller than 37mm, can I use those pololu micro metal motor? www.pololu.com/product/3046 ----> 12V, 0.8A @stall, 32rpm, 125 oz-in (0.88 n-m) OR www.pololu.com/product/2372 ----> 6V, 0.7A @stall, 22rpm, 80 oz-in (0.56 n-m) I wonder if I can use these motors for a 6dof model, and if it'll be better 12v or 6v.. the size would be perfect for a almost 1:10 model Thanks, Gabriel. Sorry forgot about this thrend. I already have tried the 6v version micrometal and they are awesome. I used 5v on them. If you can use the 12v version one as it has less current under stall and has better brushes. Thanks Thanos
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