pic: Whats going on HERE?

[gorrilla]

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I'm curious... What sort of numbers have you done on the plastic worm gears, and the amount of weight they're going to take? If I recall from my own off season tests, they aren't the strongest things out there...

Also, how are you going to deal with wire twisting? Are we allowed 4 window motors, and have you bought 2 more of the current years? We're not allowed any of the previous years, as far as my understanding goes.

[gorrilla]

swerve drive perhaps


really dident take that long to build 4 of them, we found these wonderful boxes that were just the right size.....



we put them under our 2008 robot and the worked great,
only about 40 pounds of pressure on them i believe, there just prototypes(our first directly driven wheel) we have other more powerful motors that we could switch them out for quickly if they dont hold up, only six motors used total(4 for driving wheels and two for turning them)

as for the wires,thats something we'll have to figure out later


ps.. it may or may not be, based off your cad you posted awhile back.....

[Sam2197]

ya have to wonder... what are the cims being used for????

[gorrilla]

Originally Posted by Sam2197

ya have to wonder... what are the cims being used for????

thats a suprise.......but i can tell you that thier needed(badly) in other places.... which is why we went for the window motors

Originally Posted by gorrilla

we put them under our 2008 robot and the worked great,
only about 40 pounds of pressure on them i believe, there just prototypes(our first directly driven wheel) we have other more powerful motors that we could switch them out for quickly if they dont hold up, only six motors used total(4 for driving wheels and two for turning them)

as for the wires,thats something we'll have to figure out later


ps.. it may or may not be, based off your cad you posted awhile back.....

I'm confused as to how this could be based off my CAD. I've never done a direct drive, nor would I ever consider it. If something breaks in this module, the entire thing needs to come apart to change it.

The use of thin plate for a module will allow it to flex a hefty amount, and deflection isn't good. A tiny amount as small as .125" of deflection will take your wheel's contact patch down by somewhere around 60%, depending on the size. If it's not rigid, you lose HUGE amounts of efficiency when turning.

As far as strength of the Window motors, keep us posted on how they do.

[gorrilla]

Originally Posted by CraigHickman

I'm confused as to how this could be based off my CAD. I've never done a direct drive, nor would I ever consider it. If something breaks in this module, the entire thing needs to come apart to change it.

The use of thin plate for a module will allow it to flex a hefty amount, and deflection isn't good. A tiny amount as small as .125" of deflection will take your wheel's contact patch down by somewhere around 60%, depending on the size. If it's not rigid, you lose HUGE amounts of efficiency when turning.

As far as strength of the Window motors, keep us posted on how they do.

well the box(mostly inspiriationaly)

actually it dosent all have to come apart....the way we built it, the motor is bolted to the outside of the box, the hub is attached to the output gear, the hub is attached to the wheel, and a 1.5inch 3/8th bolt is put through a bearing which is then bolted to the other side

to remove the entire motor and wheel and replace it, takes about 3 minutes


yeah, the plate is pretty thin, we are waiting for comformation if a local machine shop can make us some thinker ones(say 1/8inch alluminum?)

pretty much, it was built to be as cheap and simple as possible(as i said its our first time Not using tank drive) we're feeling pretty ambisious this year

ps.. we have 4 window motors for driving the wheels, and we have 2 other motors that came in the kit(not sure what they are, like a bigger more metalic version of the window motor?)

[Akash Rastogi]

Originally Posted by gorrilla

well the box(mostly inspiriationaly)

Can you link to the exact one please? I don't see the point of this design btw, what exactly is the point?

Hey, just keep an eye on this:

<R51> Motors specifically permitted on 2009 FRC ROBOTS include:
A. All motors, actuators, and servos provided in the 2009 Kit Of Parts,
B. An unlimited number of COTS servos with a maximum output torque of 55 oz-in and
maximum rotational speed of 100 rpm at 6 Vdc (e.g. HITEC model HS-322HD or HS-325HB
servos, as provided in the Kit Of Parts),
C. An unlimited number of FIRST Tech Challenge (FTC) servos (HITEC HS-475HB servos),
D. One or two additional 2-1/2” CIM motors (part #FR801-001 and/or M4-R0062-12) in addition
to those provided in the Kit Of Parts. This means that up to four, and no more, 2-1/2” CIM
motors can be used on the ROBOT.

I'm not sure how you plan to drive your robot with 4 of a motor that we're only allowed to use 2 of...

[Mike8519]

Sorry to bear some bad news...

<R52> Items specifically PROHIBITED from use on the ROBOT include:
A. Electric motors and/or servos different from, or in addition to, those in the Kit Of Parts, with
the exception of those specifically permitted by Rule <R51>.

You only get two window motors (1 of each orientation) in the KoP so this setup is not legal.

[eugenebrooks]

Originally Posted by gorrilla

ps.. we have 4 window motors for driving the wheels, and we have 2 other motors that came in the kit(not sure what they are, like a bigger more metalic version of the window motor?)

You need to check that you are not violating the window motor count.
One left and one right denso motor was in the KOP, providing two
motors, not four.

Eugene

[gorrilla]

Originally Posted by CraigHickman

Hey, just keep an eye on this:



I'm not sure how you plan to drive your robot with 4 of a motor that we're only allowed to use 2 of...

yeah we saw that, we'll have to work something out(not to hard to get around)



oh, this one http://www.chiefdelphi.com/media/photos/28443
they were going to be v-shaped originally, but then we found those boxes...... and its the same tring setup to(with the sprocket up top)



and we know, we can only use two window motors, theres these other ones that are bigger that we are trying to make work

Originally Posted by gorrilla

]

and we know, we can only use two window motors, theres these other ones that are bigger that we are trying to make work

So there aren't 4 of them. There's two separate kinds. How are you planning to keep the robot speed constant with two different wheel speeds?

[Vikesrock]

I'm confused as to how this would work. If they are indeed crab modules you have 2 Denso Window Motors (1 left, 1 right) and 1 Keyang motor to work with with similar form factors.

What motors are you planning on using?

[gorrilla]

Originally Posted by CraigHickman

So there aren't 4 of them. There's two separate kinds. How are you planning to keep the robot speed constant with two different wheel speeds?

on the prototype there are(sorry if i dident make that clear)

the window motors are 90pm and the other ones are like 85 so it shouldent make that much of a difference(i hope) any suggestions?

we could also use the globe motors if we have to.....

just what we had lying around is what we used...the final version will absolutely be legal...


another reason for the swerve drive is that a tank drive wont turn the robot(so we thought why turn the robot, when we could turn the wheels?)