# Reasonable Speed

What would be a reasonable speed for a 120 pound robot to pass 54 feet?

Four seconds

If you agree there is acceleration and deceleration, then around 18 fps might be a good number. Consider controllability - 100 fps is possible, but would it be good? OTOH, 5 fps would be very powerful in a pushing match…if you could get there before the match ends.

You need to find out from your strategy folks what you need to accomplish, and set a speed based on that, not SWAG.

Don

At IRI concerning drive trains to be used in a FIRST match Bill Beaty he said that a good speed that is just below where your driver may have problems controlling the robot would be around 10-12 fps. I agree with him on this because once you have your robot going above this speed your driver may have problems controlling the bot especially if your drive system is not fine tuned. It also could cause problems when your bot has a high COG and you would like to turn pretty quickly. Well as physics dictate, that maybe hard to do without having your robot fall over on its side. Just some things to think about.

a good, solid, general fps to go by is around 11-12…you should have reasonable power w/ quick speed

One other important point to remember if you are using very high friction tire material or if you are planning to “skid steer”, ratios that result in ~8 ft/sec or higher can cause your motors to stall or run at a very high current before the wheels spin. This can be very bad because it can cause your circuit breakers to trip or, if the motors get too hot, they can stop working as well.

Are we talking shifting or not shifting? If your robot moves at 12fps, as others have indicated, your driver will have a field day attempting to make those minute direction changes. It’s really hard. 5 fps is definitely way to slow, as you’ll probably get within scoring range when your offensive period ends! :eek: I’d say somewheres in the 7-9 fps range. Which makes it about 6 or 7 or so seconds.

I think our robot will end up being around 11-1 to somewhere as low as 7-1 using the cims

The kitbot gearboxes generally give the robot a good balance of speed and power, if a little on the fast side. But you can always fix that in the code

Last year, we could achieve 14 fps going full throttle, and if pushing something, well, we managed to push a robot running skyway wheels sideways across the arena at maybe 4-5 fps. So, it’s not always a complete tradeoff between power and speed. 2 motors in each of those kit gearboxes can be mighty powerful if they power 7 inch wide drive wheels with conveyor belt material treads.

Power is relative (in the pushing sense. Obviously mechanical power is absolute).

While you may be able to push a great deal using the kitbot with 4 motors, relative to another robot using the same setup, your robot is not powerful at all.

So as long as you’re facing a robot that’s 1)using fewer motors than you or 2) is using the same amount of motors but geared to go faster, your robot will be relatively powerful.