Crazy Drive Train Ideas

[JamesCH95]

Originally Posted by Bjenks548

So I have another drive train running through my head. I was wondering what gear ratio would be used to power an individual wheel using a ban bot moter and what it would be for a fisher price moter. Also I thought i remebered that we only get 2 bb and 2 fp moters, is that right?

ban bot motor? err...

Yes, teams typically get 2 FP motors.

What sized wheel?
How fast do you want to go?

Divide the circumference of the wheel by 85% of the motors free speed (a rough approximation for full speed under load) then multiply by the gear ratio (1:15 reduction would mean multiplying by 1/15th) and there's your top speed.

Generally 5ft/s is a good pusher robot, 8ft/s is quick with good acceleration, and 11ft/s is FAST with moderate acceleration.

[Chris is me]

Originally Posted by JamesCH95

ban bot motor? err...

For example, this year's RS-555's that no one used.

Generally 5ft/s is a good pusher robot, 8ft/s is quick with good acceleration, and 11ft/s is FAST with moderate acceleration.

With 4 CIM motors. Your acceleration will take a hit as will your pushing ability *using other motors*

[Hawiian Cadder]

if anyone knows how a auger driven drive would be affected by the rules, my team is seriously considering it, it would be holonomic, with incredible traction, it could handle soft terrain as well as bumps. we are looking at ice fishing augers right now for cheapness and availability.

[Chris is me]

Originally Posted by Hawiian Cadder

if anyone knows how a auger driven drive would be affected by the rules, my team is seriously considering it, it would be holonomic, with incredible traction, it could handle soft terrain as well as bumps. we are looking at ice fishing augers right now for cheapness and availability.

Unfortunately, the metal or plastic digging into the carpet would have been an illegal traction device this year, if I understand correctly.

[Alan Anderson]

Originally Posted by Hawiian Cadder

if anyone knows how a auger driven drive would be affected by the rules, my team is seriously considering it, it would be holonomic, with incredible traction, it could handle soft terrain as well as bumps. we are looking at ice fishing augers right now for cheapness and availability.

Use mecanum wheels. They work based on almost exactly the same effect, and they have two major advantages. First, they are carpet-friendly. Second, they will actually work.

[M.Wong]

Originally Posted by ,4lex S.

BALL DRIVE!!!

One large ball with a traction wheeled motor rolling said ball in the y direction, and another in the x. I can't see this ever being practical, but it would be fun to build and program.

We did this for a community outreach robot. Instead of treaded wheels we used omni wheels. At first, he was designed to balance on it, but we decided to put some casters on him. The large basketball we used got worn down to the fabric.

[548swimmer]

Originally Posted by M.Wong

We did this for a community outreach robot. Instead of treaded wheels we used omni wheels. At first, he was designed to balance on it, but we decided to put some casters on him. The large basketball we used got worn down to the fabric.

How did you secure the ball? That's the only issue I have with ball drives.

[Lil' Lavery]

Originally Posted by JesseK

I don't understand why all teams want the drive train to do everything for mobility. If the rules allow for it, why has no one even prototyped something like a tethered Quad Rotor that lifts off and gets the game object? Sure, the thing would probably get beat up during a finals match but the sheer success in prototype will spur a LOT of creative thought come build season. Of course just implementing a quad rotor with limited amounts of motors is a feat and requires its own innovations worthy of patents and PHD's, heh. Then there's the control component, which many programmers would salivate at the chance to do, and the sensor feedback component which boggles the mind of even the smartest professionals.

If only a tether wouldn't prevent them from doing this...

[Hawiian Cadder]

augers would work, two augers with oposite direction helixes, the spin the opposite direction of each other to go forward or backward, altering the speed that each one drives would achieve holonomicacy. to go sideways, both spin in the same direction, due to the way the screws are set up it will not be vulnerable to pushing from one side while traveling at 90 degrees like mechanum is to some degree, i think ill ask on Q&A next year if that would be legal.

[Collin Fultz]

Originally Posted by Hawiian Cadder

drives would achieve holonomicacy.

/tangent/

I'm not 100% sure this is a word, but if not, it should be. Or would it just be holonomicy? Either way, it's finding it's way into my vocab.

/tangent/

[Jared Russell]

Originally Posted by Hawiian Cadder

augers would work, two augers with oposite direction helixes, the spin the opposite direction of each other to go forward or backward, altering the speed that each one drives would achieve holonomicacy. to go sideways, both spin in the same direction, due to the way the screws are set up it will not be vulnerable to pushing from one side while traveling at 90 degrees like mechanum is to some degree, i think ill ask on Q&A next year if that would be legal.

Think of the interactions between the "ribs" of the auger and the ground. In order to move, there will necessarily be slip. Slip means that you have (sometimes significantly) less available tractive force - remember the differences between static and dynamic friction. So you will accelerate more slowly - and push with less force - than with a mecanum wheel.

Additionally, it is hard to find a material that can slip against the carpet, yet still have traction, yet won't destroy either the carpet or itself very quickly. The analogy would be if you made a "kiwi" drive (wheels at 45 degree angles to the body) with regular wheels - everything would scrub the ground all the time. It kills your wheels, it kills the carpet, and it kills your efficiency.

All of this goes out the window (somewhat) if you are driving in sand, but otherwise I would think long and hard before implementing this.

[gblake]

Originally Posted by Collin Fultz

/tangent/
it's finding it's way into my vocab.
/tangent/

/tangent//tangent/

Argh!!!!!! Please say it isn't so!

Good words already exist. Take the time to discover and use them. Vocabulary and writing skills are important. Practice using existing words precisely instead of cluttering your vocabulary with ambiguous jargon that only creates the illusion of technical information.

FYI - Most good employers care greatly about this....

/tangent//tangent/

Blake

[JesseK]

Originally Posted by Lil' Lavery

If only a tether wouldn't prevent them from doing this...

Make an offseason t-shirt bomber and it can do that . Make it a gimbaled tilt-quadrotor and then it can do spins while flying on it's side to wow the crowd in a match. Heh, make it a gimbaled quad-tiltrotor powered from a single motor and you can write your meal ticket for life almost. (It's theorectically mechanically feasible, but quite complex to do.)

Then there's the element of autonomous maneuvers that the driver could command the quadrotor to do during the match. It brings about a systems range of questions, ranging from how the user inputs the command at the driver's station to how the quadrotor interprets an executes the maneuver regardless of its current orientation or flight path.

[lim shi hao]

how about combining all the omni-directional drive together??

[Tom Ore]

Originally Posted by Hawiian Cadder

augers would work, two augers with oposite direction helixes, the spin the opposite direction of each other to go forward or backward, altering the speed that each one drives would achieve holonomicacy. to go sideways, both spin in the same direction, due to the way the screws are set up it will not be vulnerable to pushing from one side while traveling at 90 degrees like mechanum is to some degree, i think ill ask on Q&A next year if that would be legal.

Not sure if this link has been posted earlier in the thread but here it is:

http://www.youtube.com/watch?v=L3NGCL-efRM