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Unread 24-06-2002, 02:30
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#0047 (ChiefDelphi)
 
Join Date: May 2001
Location: Pontiac, MI
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Re: EVERYONE, ANSWER THIS PLEASE!!!

Posted by Andrew wyatt at 03/19/2001 6:35 PM EST


Other on team #524, Alpha Omega Robotics, from South High School.


In Reply to: EVERYONE, ANSWER THIS PLEASE!!!
Posted by Rob DeCotiis on 03/18/2001 1:50 PM EST:



The drive system is THE single most important thing on the robot, which basically means you should take devote the most care, time, money and facilities to it.
I've come up with a few helpful tips/pointers for designing a good, workable drive assembly.

1. castors suck. Have you ever tried pushing a heavy cart around that has four castors? ever notice how hard it is to steer and reverse in close quarters?
better yet, try to push one up an incline. the front doesn't track straight and tries to lean over to one side or another, which puts you right off the incline or worse.

2. power all your wheels, all the time. having four wheels does you no good if two of them aren't powered,
because the unpowered wheels add to the amount of drag and add no traction.

3. don't use stock wheelchair wheels. the stock wheel chair wheels provided aren't the main drive wheels, and aren't really designed for maximum traction. We turned our wheels down to 5.75 inches diameter (to get rid of the "hump" and leave a nice, flat surface.)
we then milled 48 slots in the outer surface of the wheel , .05 inches deep and .125 inches wide at 200 RPM. Rubber doesn't machine well, so we were left with wheels covered in a soft rubber fuzz that gripped carpet like the hand of GOD.

4. Keep it heavy. the weight limit is 130 pounds, and there is very little reason to build a light, spindly robot that weighs 30, especially given the chance of incidental contact. We built ours up near the hairy edge of the weight limit (126.5 pounds) and we had to replace the rivets in our roll cage mounts because we were impacted several times.

5. keep your CG low. as low as possible. lower than floor level if you can. Having a low CG insures that you won't lose traction when you go over the bridge or flip coming down it, and it is essential if you have to do any kind of manipulation of said bridge. (if you'll notice, our robot lifted its front wheels of the ground. if we had a high CG, we'd have regularly fipped ourselves over.

6. Do your drive system FIRST. while manipulators are nifty, the drive system allows your drivers to gain valuable experience driving it around. Good drivers can overcome bad equipment, which gives everyone more points.

7. make sure you have a machinist on staff. machinists are handy people, and ours was quite invaluable, as he knew exactly what needed building, because he was there every meeting.

8. Don't switch drivers every round if you can help it.
have one driver drive EVERY round. having multiple drivers leads to inconsistent performance and makes it difficult to scout, in addition to the training problems inherent in training multiple people on one robot to high levels of proficiency.

I hope these help.
If you have ANY questions, requests, anything, please email me.


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