09-10-2003 00:54

sanddrag

Are those FP motors? What kind of reduction system do you have?

09-10-2003 01:01

Cory

Those are drills. We only had two FP's in 2002, and three drills.

Cory

09-10-2003 01:01

Ken Leung

They should be the Drill motors. Back at 02', there were 3 drill motors in the kit of parts.

09-10-2003 01:08

Wetzel

Mmm....preeetty....
I bet the code is really ugly though, and with the languge shift to C I wonder how much rewritting will have to be done.


Wetzel

09-10-2003 01:13

FotoPlasma

Well, logically, with the language change, it'd be 100% rewritten. Concepts may stay the same, but that's probably all.

I would very much like to see the code to control this kind of drivetrain, for either the BS2SX based control system, or, when we get it, the PIC based control system.

09-10-2003 01:14

James114

wheel design

i want to know what the design of each individual wheel is, i have tried designing wheels like those and it can be difficult.

09-10-2003 01:25

Wetzel

I was wondering how much the mathwork in particular would have to change.

Lots of designwork over the summer, and its back to the drawing board.

Hurray for the real world.


Wetzel

09-10-2003 02:01

sanddrag

My bad. I knew we only got 2 FP's. I don't know what I was thinking. Of course they are drills. But someone please tell me or give a photo of the reduction between the motor and the wheel...

09-10-2003 11:36

Kris Verdeyen

Complex digital control system

Instead of complicated math, they got cute with some mechanical hardware - they could be up and running in C in ten minutes:

09-10-2003 20:32

Matt Krass

Quaint...

Cheesy, but Quaint.

J/k that's actually pretty cool (and amusing). But, was it hard to drive?

09-10-2003 20:34

EStokely

<<Instead of complicated math, they got cute with some mechanical hardware - they could be up and running in C in ten minutes>>

Hey thats not bad!!!

At first I thought it was just a joke but it makes sense to me.

I may just file that away for future explotation. :-)

thanks for the pic

11-10-2003 14:15

ajlapp

stuff i explained in other threads

i explained some of these controls and stuff in another thread, but i'll throw it up here for you guys also.

those are drills for the record, and i could show you how to make those omni-wheels, with the right tools they're very simple to build.

check out this video for a look at it in action.

http://stuweb.ee.mtu.edu/~alkrajew/FIRST/kiwi.mpg

CONTROL STUFF

we used three normal joysticks, connected together with a "y"-shaped yoke, and ball joints. the x-axis of each stick was unwired, and the threey-axis of each stick were wired into one coupler.......just to save space on a cramped IO.

so each y-axis of the joystick represents the velocity vector of one wheel. the joystick does the complex task of converting cartesian coordinates to polar coordinats inherently.

the robot goes in the direction the stick is pushed, or spins if the stick is rotated in the center.

the attached pictures show how the joystick is a vector based model of the real robot......instead of a motor and gear set, you have a potentiometer. you manually input the velocity of each motor and the robot responds. (both pictures were prototypes)


problems!
our drivers created what they called slip. this was their method for driving. it was based on a general direction rather than a finite point in space. they kind of glided the robot to its position. the joystick doesn't make it super easy to go in straight lines, but straight is irrelevant when you can go anywhere instantly.

we worked around this by making multiple faces for our robot to operate on......front didn't really matter.

11-10-2003 14:56

Madison

Re: Complex digital control system

Unfortunately, there's now a precedent that makes it illegal to modify the joysticks in any way. So, fun with math, anyone?

11-10-2003 15:45

JVN

Re: Re: Complex digital control system

As a Mech-E, I'd like to think we could find some way of coupling 3 joystick together in a similar way to the one shown above.

Duct tape anyone?

Programming math is for ninnies!

11-10-2003 22:42

Jmoo

Really simple to drive, soooo easy to program, I just got on this team last year. This summer, I took our 2002 robot to my house. Added a brain, programmed it up in like 1 minute, and just went nutz. Only problem is that it's only good on flat carpet....

12-10-2003 18:21

ajlapp

joysticks no big deal

making a new stick without modifying the originals is no problem.........in fact some of this testing has been done. but who knows if we'll ever use the drivetrain again.

i really love it, but i'm not convinced that its a game winner, and since we haven't had three matched motors again, its made me more skeptical.

12-10-2003 18:54

Rickertsen2

Is the thing hard to stop?

12-10-2003 19:03

ajlapp

not sure what you mean

is this a traction question? or something else?

13-10-2003 08:12

Gadget470

Team 857's old website had a great 8mb video of this thing in action.

(Link from another thread: http://stuweb.ee.mtu.edu/~alkrajew/FIRST/ Video includes Dope's cover of Right Round = woo!)