pic: Team 857 Prototype Killough 2002

[ajlapp]

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.