Team 840 hurdles-VIDEO
 

This is a video of our robot hurdling (on Saturday!) over our wonderful, plastic practice overpass.... thanks to our computer lab teacher (who is not normally involved with the team!) for putting this up!

http://www.youtube.com/watch?v=tBt0MZJKbJs

Re: Team 840 hurdles-VIDEO
 

That looks really neat! It sure feels good when it all comes together, doesn't it?

I do have a couple of questions, though... it looks like you seem to have a bit of trouble turning. Would it help to put omni-wheels on one end? Maybe this was more new drivers being cautious than a mechanical difficulty, but in our experience we have found that the carpet offers even more traction... and presents more challenge for turning... than pavement, so if you sensed there was a problem, it is probably something you will want to deal with.

I'm also curious about whether you checked to make sure the robot is in compliance with the 80 inch rule that all parts of the robot have to be within 80" of each other at all times. I apologize for even mentioning it as the rule has pretty much been discussed to death here on C.D., the rule book and team updates and I'm SURE that you have checked, but it looks like... and again I emphasize looks... like this may be an issue.

In any case, congratulations and good luck at your regional!

Jason

Re: Team 840 hurdles-VIDEO
 

I agree that it would seem that Omni's would be in order. If you can't get omni wheels by your first competition casters would work too. Another slight concern I had was with the loud pooping sound when the arm rose up. Was that the chain slipping? If so tensioning those chain linkages would definitely be recommended, especially if you're using pots on the arm joints. Nevertheless the bot looks awesome, great job guys!

Mike C.

Re: Team 840 hurdles-VIDEO
 

We originally tried casters, but they had massive problems with grip. One of our mentors repeatedly suggested omniwheels, but sadly he was ignored... something for debriefing, I guess :(
We've used a similar drivetrain many times before, and it's never had any problems on the carpet.

As the "rules guy" that was my pet peeve... but I came at the robot with the tape measure from every angle, and I couldn't find anything (after we cut a little bit off... >_>)

Thanks! :D

Rex114: Yes that was the chain, yes we are using pots, and yes, we are definitely planning on tensioning it >_> See you at SVR!

Re: Team 840 hurdles-VIDEO
 

You can try wrapping zap ties around the wheels at one end to reduce the lateral co-efficient of friction. (Just realized that isn't the best description... there are two ways to wrap zap ties around the wheel. I mean the "short way" through the hole between the spokes, not about the circumference.) It isn't quite the same as omni wheels, but it might help, especially if you can move your CG (move the battery) a bit to put more of your mass over the non-zap tied wheels.

It doesn't do a lot... but maybe you only need a little.

Also don't be afraid to consider changing to omnis now. Order them up from AndyMark and throw them on Thursday morning at your competition. If you aren't in the first week of competitions you can even build an "upgrade part" for mounting them (since you are the rules guy, I won't repeat all the fix-it window stuff here)... or just buy something from AM. You'll find that omnis make an indescribably HUGE difference, and that your competition will be much more fun if you can turn easily.

And it is more than okay to say to your mentor, "Hey... you were right. But thanks for letting us find out for ourselves. Now can you help us solve the mess we got into?"

And sorry for asking about the size, but I am glad to know it has been checked.

Jason