Author Topic: Servo wheels  (Read 813 times)

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Offline ScorksTopic starter

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Servo wheels
« on: December 13, 2012, 09:35:31 PM »
Hey! So I'm new to building, and I was had a question. I have two 180 degree servos. I wanted to make functional wheels on a little robot. How would I do this without having to alter the servos by making them do full continuous rotations (since I don't want to mess around with their insides. They were expensive).

Offline jwatte

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Re: Servo wheels
« Reply #1 on: December 13, 2012, 11:12:03 PM »
You cannot.

Your best bet is to buy a small cheap gear motor and a suitable motor controller.

Offline Th232

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Re: Servo wheels
« Reply #2 on: December 14, 2012, 12:16:52 AM »
The only thing I can think of is a crankshaft that the servos push back and forth, but that would be a lot more complexity, time, effort and cost than I could ever recommend.

Just do what jwatte suggested and get a different motor.
« Last Edit: December 14, 2012, 12:19:02 AM by Th232 »

Offline Gertlex

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Re: Servo wheels
« Reply #3 on: December 14, 2012, 12:25:58 AM »
You cannot.

Your best bet is to buy a small cheap gear motor and a suitable motor controller.

Or buy two cheap HS-311 servos and modify them.
I

Offline Pogertt

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Re: Servo wheels
« Reply #4 on: December 14, 2012, 01:51:38 PM »
In this link  http://en.wikipedia.org/wiki/Steam_locomotive#Steam_circuit  Please scroll down to Steam Circuit.  The article explains how the pistons are connected to the drive wheels, with the piston connecting link arms being 90 degrees out of phase.
The out of phase scheme is used, because if the rods were connected at 180 from each other, and the wheel stopped at TDC or BDC, there would be no way to get them moving again without push from another engine.

The programming of the 2 servo control pulses might be challenging, but not an impossible task.

The easiest way may be to use a look-up table to find the two positions the servo arms need to be in to generate rotary motion.


 







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Offline greywanderer012345

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Re: Servo wheels
« Reply #5 on: December 16, 2012, 12:45:20 AM »
   Really, the best and cheapest, thing you can do is modify the servos just as admin's servo tutorial explains. It's really not hard to do, and you will spend more time and money trying to figure out away around it.

   There are even tutorials out there on how to save the Pot from your altered servos by switching it out with resistors. Don't bother with any of that, as it's just not worth the time or headache, and you'll get more out of spending that time programming, adding different components, and coming up with your own designs.

    I am all about saving a few dollars, so let me know if you want a few tips in that arena (My $50 robot actually contains less than $10 hardware), but take my advice and just modify the servos.

 


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