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Unread 23-01-2005, 01:01
Jeff K.'s Avatar
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Re: Motor Placement Pros and Cons

Well, for this year's design, our robot has 4 WD with the gearbox placed as far back as we can. We are doing this because our arm is going to be in the front, and since the battery and gearboxes are the heaviest things on the robot, it'll keep the robot from becoming unstable and tipping over. Pros of this is stability. There are no cons. A con with having the gearbox placed closer to the front and having the arm hanging over the front is that the robot will tip over. But the placement of the gearbox depends on your team and where you plan on mounting the arm.
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Unread 23-01-2005, 01:18
Pattie Pattie is offline
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Re: Motor Placement Pros and Cons

I think I'm concerned that it may be easy to turn one way, but not the other and also will it be more difficult to move straight. And, as you mention, the weight won't be countered by mounting the weight in the back. Also seems like a pretty long chain to worry about. But I'm sure there has to be some really great reason to choose this design given the risks involved.

Pattie

Last edited by Pattie : 23-01-2005 at 01:23.
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Unread 23-01-2005, 01:23
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Re: Motor Placement Pros and Cons

Hi Pattie,

Let me offer my POV on this..

are you guys going to use this as a direct drive to one wheel on each side??

If so, it might be worth your while, bit the instant you try and turn, you will be doing donuts easily. my advice is mirror your robot, make each side symmetrical, it makes for much better weight distribution as well as power effeiciency.

One mroe thing, in that current setup, you will also have some frame warp, this will happen when your robot goes to pick up something and your left wheel is trying to get traction and the other is going to be slipping (kinda the same as a posi-trac rear end)

all in all a forum is merely a tool for suggestion, and we utterly cannot swing a teams vote...

good luck!
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Unread 23-01-2005, 12:55
Pattie Pattie is offline
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Re: Motor Placement Pros and Cons

Hi Greg,

Thank you for the comments. This helps. I had never heard of a setup like this before and wondered if any other team had tried it or considered it. No direct drive was in this latest plan. I have visions of the the chassis moving diagonal. But I know I am biased from a programmer perspective - hoping this approach doesn't make the chassis veer off to one side or making one turn difficult that we have to get creative modifying code to make up difference for - so asking for other input. I really appreciate everyone's responses on this. I'm looking for the pro that makes this approach worth taking the risks. My concerns may be total nonissues. But warp on the frame is a big concern. This helps a lot.

Pattie

Last edited by Pattie : 23-01-2005 at 14:57.
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Unread 23-01-2005, 16:28
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Re: Motor Placement Pros and Cons

My team had a design like this at one point. The main advantage that this design has is that you open up the middle of the robots chassis so that wiring and placement of other components is much simpler because you do not have to run wire and hose around the motors in the middle of the chassis. However, the electrical team captain and I (Programming, and pneumatics captain) designed this.
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Unread 23-01-2005, 16:38
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Re: Motor Placement Pros and Cons

Hi Cyberwolf. Thanks for the response. You say you had this design at one point - what were the reasons you did or did not use this design? Were there any fatal concerns with this design?

Pattie
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Unread 23-01-2005, 16:42
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Re: Motor Placement Pros and Cons

The reason we eventually decided against it was that we were going to go with a 6-wheel drive train if the chains connecting the wheels broke we wanted out center wheel to stay powered so in the end we decided to put the motor in the center of the robot. In addition, it put the weight above our center wheels.
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Unread 23-01-2005, 20:00
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Re: Motor Placement Pros and Cons

well just an imput from a lego stance, i have used this in many lego models with much success. but lego is slightly different as most of you know. why i used it in lego, because haveing them in that config allowed me to leave the minimum width to 5 blocks rather than 10
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Unread 24-01-2005, 01:22
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Re: Motor Placement Pros and Cons

I didn't take a look at the word document, but because our gearboxes are so large we are placing one at the front right wheel and one at the back left wheel. Not optimal but functionally the same.
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Unread 24-01-2005, 11:21
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Re: Motor Placement Pros and Cons

Have you had any issues with driving crooked at all?
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