Robot chassis dilemma
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Posts: 46,084
After year or so of scavenging/buying, I am finally in the home strech for
my new robot. I have a huge package of aluminum due to show up on my
doorstep momentarily, and my electronics are almost all gathered [noparse]:)[/noparse] Now I
have the problem of deciding which of my chassis possibilities is the one to
build. I spent $20 on 4 7" diameter lawnmower wheel (with very nice
tread...), so I want to use them. My original plan was to stick all four
wheels on the bot and have four-wheel-drive and a differential-steering
setup. I figured I needed to power all the wheels so they wouldn't drag as
much when turning. I was wondering what you people thought about this... it
is more expensive to do it this way, but I would like it more, but I am
afraid that it may not work well. The other possibility is only use two
wheels and a caster, so the setup would be like a giant BOE-bot. I know
that would work because my last robot did that on a smaller scale, but I
love the idea of 4WD. One thing that you may wish to know if you are going
to offer a suggestion: either way, the robot will be more than twice as tall
as it is wide (10" wide, 20+" tall). Thanks for suggestions ahead of time
[noparse]:)[/noparse]
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my new robot. I have a huge package of aluminum due to show up on my
doorstep momentarily, and my electronics are almost all gathered [noparse]:)[/noparse] Now I
have the problem of deciding which of my chassis possibilities is the one to
build. I spent $20 on 4 7" diameter lawnmower wheel (with very nice
tread...), so I want to use them. My original plan was to stick all four
wheels on the bot and have four-wheel-drive and a differential-steering
setup. I figured I needed to power all the wheels so they wouldn't drag as
much when turning. I was wondering what you people thought about this... it
is more expensive to do it this way, but I would like it more, but I am
afraid that it may not work well. The other possibility is only use two
wheels and a caster, so the setup would be like a giant BOE-bot. I know
that would work because my last robot did that on a smaller scale, but I
love the idea of 4WD. One thing that you may wish to know if you are going
to offer a suggestion: either way, the robot will be more than twice as tall
as it is wide (10" wide, 20+" tall). Thanks for suggestions ahead of time
[noparse]:)[/noparse]
______________________________________________
FREE Personalized Email at Mail.com
Sign up at http://www.mail.com/?sr=signup
Comments
would be unstable at that height, especially over rough ground. Do you have
any hills it will go up?
What about a 4 wheel setup, 2 drive wheels in back, and a floating axel up
front. Such as tractors use. I refer to the wide front axle tractors, not
the 2 close together tricycle gear tractors.
A floating axel has a central Pin/Bolt that it will rotate around, This
keeps the front wheels on the ground, pretty much all the time.
4 wheel drive I should think would eat up more battery power. If you drive
both rear wheels which is a true positraction (as opposed to a car having a
differantial) you gain full time traction from the 2 rear driven wheels.
I also have to come up with a design soon for outdoors. I have been
considering tracks, but they really draw the juice when turning. I have many
hills, and rough terrain so had thought of tracks. I like the mars rover 6
wheel design also, if I could get a drawing of exactly how Nasa did it.
Somehow they turn the rover without wasting a lot of battery power. My toy 6
wheel rover simply turns like a bulldozer, eating juice in the process.
Good luck to you.
At 02:30 PM 3/8/2001 -0500, you wrote:
>After year or so of scavenging/buying, I am finally in the home strech for
>my new robot. I have a huge package of aluminum due to show up on my
>doorstep momentarily, and my electronics are almost all gathered [noparse]:)[/noparse] Now I
>have the problem of deciding which of my chassis possibilities is the one to
>build. I spent $20 on 4 7" diameter lawnmower wheel (with very nice
>tread...), so I want to use them. My original plan was to stick all four
>wheels on the bot and have four-wheel-drive and a differential-steering
>setup. I figured I needed to power all the wheels so they wouldn't drag as
>much when turning. I was wondering what you people thought about this... it
>is more expensive to do it this way, but I would like it more, but I am
>afraid that it may not work well. The other possibility is only use two
>wheels and a caster, so the setup would be like a giant BOE-bot. I know
>that would work because my last robot did that on a smaller scale, but I
>love the idea of 4WD. One thing that you may wish to know if you are going
>to offer a suggestion: either way, the robot will be more than twice as tall
>as it is wide (10" wide, 20+" tall). Thanks for suggestions ahead of time
>[noparse]:)[/noparse]
>
>
>______________________________________________
>FREE Personalized Email at Mail.com
>Sign up at http://www.mail.com/?sr=signup
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Sincerely
Kerry
Admin@M...
WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
Kerry Barlow
p.o. box 21
kirkwood ny
13795
http://home.swbell.net/daweasel/robot-1.jpg
http://home.swbell.net/daweasel/robot-2.jpg
http://home.swbell.net/daweasel/robot-7.jpg
The whole thing is 12 inches in diameter and the motors / wheels are
positioned for a little more than an inch of ground clearance. Most of the
mechanical platform will be bare except for batteries and some clamp-on
sensors. The electronics platform will be about 3 inches higher and sit
right on top of the gel-cell.
I used kids scooter wheels for the coolness factor. They even make them in
offroad varieties. Here is a link if you are interested.
http://www.jdrazorscooter.com/diecalrubwhe.html
Search for "ball transfer casters" to find info on the casters.
Original Message
> After year or so of scavenging/buying, I am finally in the home strech for
> my new robot. I have a huge package of aluminum due to show up on my
> doorstep momentarily, and my electronics are almost all gathered [noparse]:)[/noparse] Now I
> have the problem of deciding which of my chassis possibilities is the one
to
> build. I spent $20 on 4 7" diameter lawnmower wheel (with very nice
> tread...), so I want to use them. My original plan was to stick all four
> wheels on the bot and have four-wheel-drive and a differential-steering
> setup. I figured I needed to power all the wheels so they wouldn't drag
as
> much when turning. I was wondering what you people thought about this...
it
> is more expensive to do it this way, but I would like it more, but I am
> afraid that it may not work well. The other possibility is only use two
> wheels and a caster, so the setup would be like a giant BOE-bot. I know
> that would work because my last robot did that on a smaller scale, but I
> love the idea of 4WD. One thing that you may wish to know if you are
going
> to offer a suggestion: either way, the robot will be more than twice as
tall
> as it is wide (10" wide, 20+" tall). Thanks for suggestions ahead of time