robot speed

[lukevanoort]

I don't think planning a speed now will get you a head start. Unless you are mounting your wheels directly on the transmission output shaft (West Coast Drive style), it is really easy to change speeds; all you need to do is swap sprockets.

[Ed Sparks]

OK, I'll say it .......

IMHO, a top speed of 10-12 fps is a good place to start if your kicking around ideas about generic robot designs. A robot that can do this will be somewhere in the high middle of the pac as far as it's ability to beat a competitor from point A to point B on the playing field. Chances are that if there's any serious pushing to be done, you'll need to add a two speed gearbox to your design to get the torque back.

[vivek16]

the kitbot sprocket setup last year came to about 15 feet per second. it was really fast and we mostly blocked with our sides since we had a caster drive (the front had casters and the back two wheels were the drive wheels)

[lukevanoort]

Originally Posted by vivek16

the kitbot sprocket setup last year came to about 15 feet per second.

I don't know where that number came from; the kit drive system last year was geared to a maximum speed of 7.24 ft/s. Of course, that is just a theoretical top speed that doesn't take into account drive system inefficiencies, and the actual top speed is probably somewhere in the fives.

[vivek16]

umm... well our way of measuring it consisted of this: having a team member(in cross country) run down a narrow hallway of 20 feet long at the speed at which we thought the robot went at. and then timing

rookie tip: whatever you do, be more prepared than we were..

[AdamHeard]

Originally Posted by vivek16

umm... well our way of measuring it consisted of this: having a team member(in cross country) run down a narrow hallway of 20 feet long at the speed at which we thought the robot went at. and then timing

rookie tip: whatever you do, be more prepared than we were..

Why not have the robot do it instead?

[vivek16]

well the pit crew was trying to make it work
I was with the programmer because he needed the speeds for autonomous mode: ours consisted of driving across the field and waiting to defend against other robots.

-vivek

[kramarczyk]

Originally Posted by cloud_254

good point but, i'm just trying to guess for this year's competition. i know kick off isn't til jan 5th but i'm just trying to get a head start.

The best head start you can have is to get to know the tools and develop the skills that will help you do it quickly and efficiently once you get all of the information at kickoff.

Rule of thumb in picking a ratio... let the kitbot be your guide. If you want to be fast, be faster than the kitbot. If you want to be a pusher push harder than the kitbot. So for now, just plan on one reduction that you can easily change to hit any of the speeds discussed.

[alex1699]

Originally Posted by Richard

Since alex1699's school in located in the middle of Connecticut, I doubt that his team is actually a bunch of rednecks. More likely it is a bunch of yankees.

I, on the other hand, attended a public high school in the middle of South Carolina. My school was quite literally full of rednecks. Some (most?) of my best friends were rednecks. (And the rest were transplanted yankees!) Rednecks are known for many quirks that non-rednecks might find strange, but a preference for slow gear ratios is emphatically NOT one of them.

Conclusion: Adam is right, the point is ambiguous at best.

ok im sorry but we are rednecks we all have 4 wheel drive suvs and go muddin and then also rid cheap plastic quads down snow bank hills and we made are robot is a two car grudge listen to country and are town is a small town with onle about 900 kids in ar school. and then some how we got a bike stuck 3 to 4 feet feet deep in mud...... i dont no what you think red necks are but for team in the middle of Connecticut i think we are pretty "red neck".

o yes i do stink a spelling so dont correct me please....

[alex1699]

Originally Posted by alex1699

ok im sorry but we are rednecks we all have 4 wheel drive suvs and go muddin and then also rid cheap plastic quads down snow bank hills and we made are robot is a two car grudge listen to country and are town is a small town with onle about 900 kids in ar school. and then some how we got a bike stuck 3 to 4 feet feet deep in mud...... i dont no what you think red necks are but for team in the middle of Connecticut i think we are pretty "red neck".

o yes i do stink a spelling so dont correct me please....

and im not talking down my team we all love it and are have amazing fun and redneck is not a bad thing

[Richard Wallace]

Well, I just learned something. Connecticut rednecks! Who knew? My apologies.

[JesseK]

To stay on topic --

The whole speed vs. control is greatly recognised in an FTC match. Many students, when left to themselves, design their drive trains separate from the rest of the robot. So maybe they design the bots to use the large wheels with a 1:1 ratio or tiny wheels with only 1 motor per side. Then they add all of the mass of the steel and nuts and bolts above their drive train and get very lackluster performance out of it.

This is why I think that if you must go single-speed, 10fps is a good speed to aim for in FRC. Smaller wheels give you slower speed but more torque by design, and combined with a medium gear ratio will allow for decent accleration with only 1 motor per side after you've added all of the weight above it. If you make it 2 motors per side, you might even win some pushing matches.

[alex1699]

sorry about that all with the redneck thing a friend did it i didnt sorry...

[Tom Line]

Perhaps either you or your "friend" should start using punctutaion and capitalization. Right now your typing is remarkably similar.

[popo308]

Winnovation had a 4 wheeled 3 speed shift-on-the-fly coaxial swerve drive and that was great for awesome defense and good scoring capability, very controllable as well when it wasn't freaking out.