Author Topic: servo fitted in a cylinder  (Read 2987 times)

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Offline TomasTopic starter

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servo fitted in a cylinder
« on: July 28, 2009, 04:47:29 AM »
I need one for a UAV project, I would prefer it being a standard RC PWM servo, but who am I to make demands when I cant even find a single one.

Anyone know of any cylindrical servos?

Offline Soeren

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Re: servo fitted in a cylinder
« Reply #1 on: July 28, 2009, 05:39:44 AM »
Just put one in a cylinder and fill the empty space with garlic (to keep vampire pirates at bay  ;D)

Perhaps a more precise question would help???
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline wil.hamilton

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Re: servo fitted in a cylinder
« Reply #2 on: July 28, 2009, 06:31:11 AM »
I think he (or she) is possibly asking for a servo that is shaped cylindrically (like a regular electric motor is).  I honestly can't say that I've ever seen one.  Mainly due to the fact that the way servos work is with gearing, electronics and mechanical stops.  The most economical package for all of this is the rectangular box you always see. 

I'm wondering if you couldn't take the electronics from a servo and add them to a regular cylindrical gear motor.  This would be hard because it would be somewhat difficult to add the feedback that a servo has built in. 
What you might be able to do is use a regular gear motor with an encoder and use the encoder for position control.
use the google.  it's your friend.

Offline Soeren

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Re: servo fitted in a cylinder
« Reply #3 on: July 28, 2009, 07:13:23 AM »
Hi,

I think he (or she) is possibly asking for a servo that is shaped cylindrically (like a regular electric motor is).
I agree... But without specs like size and torque, my solution is just as valid as anything ('cept for the smell perhaps) - I often wonder why people asking questions finds it so hard to spec out their needs, helping others help them and ever so often I just refrain from helping those subjects, as I can help 5 others in the time it takes me to draaaag everything out of them, that they should have provided in the first post.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline TomasTopic starter

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Re: servo fitted in a cylinder
« Reply #4 on: July 28, 2009, 07:24:14 AM »
wil.hamilton, you are absolutely right. A cylindrically shaped servo. Or as I said, a servo fitted in a cylinder (And I'm a he ;))

Soeren, right now I don't have the specs for the servo. The specs will have to come later on, as I dont know the weight of my robot and therefor I dont know what kind of demands I have to the servo(s). I just needed to know if there is anyone manifacturing these. So far it doesnt look to good.

I need the servo to make a special wing to an early UAV prototype, which is going to use a different way of turning, twisting and so on (compared to the regular UAVs). I just need this last bit, a cylindrical servo, to reduce the potential turbulence from the propellors. I think I can create a prototype which uses the regular servos as well, but then Im going to have to change my design radically. May just as well start all over again (got it drawn in solidworks already).

Offline wil.hamilton

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Re: servo fitted in a cylinder
« Reply #5 on: July 28, 2009, 11:42:04 AM »
instead of totally reworking your idea, see if what i proposed would work (using a gear motor w/ encoder)
micro-drives.com has powerful gear motors w/ encoders (some that run really slow w/ lots of torque) that would work well for something like that.

the only thing about micro-drives is that they're kind of expensive ($75-100) depending on what you want, they mainly sell motors in large lots (1000+) so you'd be hard pressed to get a deal
use the google.  it's your friend.

Offline Razor Concepts

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Re: servo fitted in a cylinder
« Reply #6 on: July 28, 2009, 12:24:51 PM »
Maybe figure out a linkage setup so the servo doesnt have to be in a location where its aerodynamically affected?

Offline wil.hamilton

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Re: servo fitted in a cylinder
« Reply #7 on: July 28, 2009, 12:59:22 PM »
Maybe figure out a linkage setup so the servo doesnt have to be in a location where its aerodynamically affected?

If you could maybe post one of your solidworks renderings of it and we could see where the servo was to be mounted, we could help come up with a workable alternative?  This may not be a plausible option though, depending on the nature of the work.
use the google.  it's your friend.

Offline TomasTopic starter

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Re: servo fitted in a cylinder
« Reply #8 on: July 28, 2009, 11:48:41 PM »
Razor concepts, I've thought about that. I can do this by moving the servos to the center of the robot, but that will also make the UAV more unstable (with a very concentrated center of gravity, it should preferrably be a low and wide center of gravity for optimal stability).

Wil, It's just a hobby project for myself as of now, so I'll probably post some sketches later on (im at work now :)). You'll understand alot better then.

I'll check out the geared motors with encoders. I guess I don't need 1000 of them, but if they are produced then its a start.

Thanks for the help guys.

Offline wil.hamilton

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Re: servo fitted in a cylinder
« Reply #9 on: July 29, 2009, 08:36:33 AM »
Micro-drives isn't the only place to get motors with encoders, you could also check out lynxmotion.  They sell gear motors with available encoders there too.  (the motors run about 22 a piece and the encoders are about 26, in USD)
use the google.  it's your friend.

Offline Soeren

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Re: servo fitted in a cylinder
« Reply #10 on: July 30, 2009, 04:59:12 AM »
Hi,

If you get a motor with a planetary gear the shape is catered for. Some of them can be had with encoders too. They won't work as servos directly, but the encoders could probably be modified to give absolute position out.

Here are some quality stuff (probably a bit too expensive though):
http://www.transmotec.com/dc-motors/Planetary-Gear.aspx
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline TomasTopic starter

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Re: servo fitted in a cylinder
« Reply #11 on: July 31, 2009, 03:24:08 AM »
Thanks for the tip.

I think I will try changing the design of the UAV for now, and if it fails I'll try the encoded motors.

 


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