dc motor selection?

dimitrizmech

hi,
i want to construct a robot arm with 6 dof, and i want to suggest me a kind of dc motor with gearhead(flange) , with very big torque about 4 to 5 Nm (i know this is big). of course 3 of them must be very strong and these is, the 1st at the base, 2nd at the shoulder and the 3rd at the elbow.
some friends suggested me a wiper motor, but it is very voluminous; and please imagine that i want 6 motors, so this maybe will increase the weight of the robot arm.

{i have taken the hb-25 to controll the dc motor with the BS2.}


please tell your opinion it is important for me!

thanks
dimitriz

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kwinn

That's a fairly large force so the motors will be bulky. You could use smaller motors as you move out from the first joint. Can you provide a rough sketch of the arm and how the joints will move?

SRLM

One arm that I've seen mounts most of the motors on the base, and uses a chain loop and sprockets to transfer motion. It saves weight that way, at the cost of mechanical complexity.

dimitrizmech

thanks for yours opinions. i have submit you the first robot arm that i make with some servo motors.

http://rapidshare.com/files/194179426/P2110061.JPG
( in this case i have the problem which introduce above to my topic (servo motor)

i know that the torque is big but this is the problem.
i think that it is better to use dc motor to be much more powerfull, but it is difficult for me to found dc motor with gearhead in ''small'' dimentions. ( this project that i make i want to be a step above from a simple "toy robot" with modeling servo motors.

sorry i forgot it, the robot it is about 50cm the arms, and with the base about 65cm...the maximum weigth that i want to lift it is 150 to 200gr.

please i wait your answer and your opinion of course!!

thanks
dimitrz

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kwinn

dimitrz, you are probably better off searching for local suppliers of motors. If that does not work then try the internet.

DJSandberg

dimitriz,

Jeep blend door motors have a lot of torque and are about the size of a deck of cards.· I expect that the blend door motors from other makes of cars are similar, but I know first hand about the Jeep ones.· They are smooth, quiet and again, very high torque.· They are used to change modes on the automatic HVAC systems.

Daryl

dimitrizmech

thanks a lot all of you for yours opinions, especially for the electric window, really thanks.
It is reality that i want, if you can, to suggested me any
supplier, where can i buy economic
dc motors, all this because of, i want something more industrial.

add that, the fact that i am from greece, it is realy problem, because it is difficult to find here dc motors in small dimentions, like this which i want.


please if you know anything tell me.
and i hope not to bore you with all these questions.

thanks a lot
dimitriz

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P!-Ro

Below is a good site for motors. Most of them are built for battlebots, so they should be extremely powerful, perfect for your project.

http://www.robotmarketplace.com/products/motors_main.html

You can also get a titanium geared servo here:

http://www.rctoys.com/rc-toys-and-parts/HIT-HS7955TG/RC-PARTS-HITEC-SERVOS.html

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PG

dimitrizmech

thanks a lot all of you, i started to look at the above sites. I hope it all go well !

thanks
dimitriz

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Prettybird

·· I am just learning this but found servo motoer have many torque specs. They also have higher prices. Check the internet or hobby stores that handle RC models. Ebay is also usefull.