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Topic: Motor for 200Nm torque (Read 289 times) previous topic - next topic

Amb34

Good morning,

I am new in this forum. I am working on a project where i have to let go a rope connected to a RC car that is pushing with a force of 15Kg. I would need a NEMA motor with a gear maybe(?), a driver and an arduino, but I didnt find any motor with this torque.

Any ideas?

Thanks :)

jremington

#1
Sep 09, 2019, 04:50 pm Last Edit: Sep 09, 2019, 04:51 pm by jremington
What do you mean by "let go a rope"? Please post a diagram with explanation showing how you think the mechanical parts should work.

You may find this tutorial on force and torque useful: https://www.pololu.com/blog/10/force-and-torque

MarkT

Good morning,

I am new in this forum. I am working on a project where i have to let go a rope connected to a RC car that is pushing with a force of 15Kg. I would need a NEMA motor with a gear maybe(?), a driver and an arduino, but I didnt find any motor with this torque.

Any ideas?

Thanks :)
Much more information please, I cannot even visualize roughly what your set-up is from this description.

Diagram perhaps?
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Slumpert

Sounds like the RC car is going to "tug" a skateboarder or something.

jremington


Amb34

Thank you all for your answers. I need to control the movement of the car by controlling the speed that the rope is being released, I am going to use different speeds and also I need that the motor is capable of keeping the car in the same place while it is pushing and no rope is being released.

Please, find attached a diagram.

Thank you for all the help.



shardaghuge

I have to control the development of the vehicle by controlling the speed that the rope is being discharged, I am going to utilize various rates and furthermore I need that the engine is fit for keeping the vehicle in a similar spot while it is pushing and no rope is being discharged.


jremington

#7
Sep 10, 2019, 04:49 pm Last Edit: Sep 10, 2019, 04:56 pm by jremington
Brushed DC motors burn out when used like that, and stepper motor torque cannot be easily controlled.

Quote
furthermore I need that the engine is fit for keeping the vehicle in a similar spot
That is a very difficult challenge. There exist DC motors designed for just that application (always stalled) but I think they are very expensive and hard to find.

If you just want to measure the force on the rope while the vehicle is struggling to move, use a luggage scale.

hammy

Why not use some form of brake instead - like a disc brake off a push bike  to control the rope ?
BTW - restraining the car like this is likely to damage the motor fairly quickly as it will be over loaded .

Seems an odd project

jremington

#9
Sep 10, 2019, 08:02 pm Last Edit: Sep 10, 2019, 08:02 pm by jremington
Agreed, as it is, the design simply won't work. The project needs to be re-thought.

MarkT

Please say _pull_ when you mean _pull_, all this talk of _push_ing is really confusing.  Nothing is pushing anything.

You have an RC car that is pulling a rope (at upto 150N), you wish to resist the motion of the RC car by
controlling the pull back on that same rope from some device.

If the car is always moving away (or stationary), no motor is needed.  However _controlling_
a varying torque accurately is not easy - using a servomotor in torque mode is actually one
of the most straightforward approachs to doing this.

However I wonder if the real problem is not to control pull, but really to control position?
Or speed?
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Amb34

#11
Sep 11, 2019, 08:32 am Last Edit: Sep 11, 2019, 08:34 am by Amb34
Please say _pull_ when you mean _pull_, all this talk of _push_ing is really confusing.  Nothing is pushing anything.

You have an RC car that is pulling a rope (at upto 150N), you wish to resist the motion of the RC car by
controlling the pull back on that same rope from some device.

If the car is always moving away (or stationary), no motor is needed.  However _controlling_
a varying torque accurately is not easy - using a servomotor in torque mode is actually one
of the most straightforward approachs to doing this.

However I wonder if the real problem is not to control pull, but really to control position?
Or speed?
Thanks to everyone for all the answers. Sorry for not using the correct terms. The car is pulling, and the variable that i want to control is the position of the car (it moves at a fixed speed). I also thought about using a servomotor, but dont know how the actual configuration would be. By the way, the situation where the engine is fit for keeping the vehicle in a similar spot it isnt essential.

Again, thank you very much :)

Slumpert

Is the car moving in a circle "around" the motor and the rope controls the diameter of the circle?

I don't understand any other way the car can be moving the the rope not moving.

MarkT

There is also a hybrid approach of using a motor and a brake - the brake ideally does all the work, the motor ensures constant speed despite the brake not being exact.  Reduces the size/power of the motor.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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