pic: Vex Teaser: What's Art been up to lately?

[jgraber]

Originally Posted by artdutra04

...
At the moment I am working on a much more complicated design that mechanically will calculate the difference between two input shafts. For example if both shafts were rotating CCW at the same RPM, the difference between the two would be zero. But if the two input shafts were moving at different speeds the output shaft would rotate in one direction (CW if shaft A is faster, and CCW is shaft B is faster) at a speed proportional to the difference of the two shafts.

Nice work on the worm gear. Now that it is a few months later, how did it go?
Were you able to make a "South Pointing Chariot"?
Was it to make your holonomic drive "driver centric"?
Links from here might give you some ideas on differentials.
http://en.wikipedia.org/wiki/South_Pointing_Chariot
I thought the screwdrive one has some promise due to no requirement for bevel or planetary gears. You might also consider just doing the integration computationally, based on optical wheel encoders on the drive wheels or drag wheels.

[artdutra04]

Originally Posted by jgraber

Nice work on the worm gear. Now that it is a few months later, how did it go?
Were you able to make a "South Pointing Chariot"?

Somewhat. I got about 70% done with it, but at that point the number of gears required to mechanically keep it "pointing South" was taking a toll on the motors and causing the robot to drift badly. This was just meant as a kind of interesting experiment in gearing, and nothing more really.

Was it to make your holonomic drive "driver centric"?

That's still a work in progress; I have the a KoP gyro at my house, and I'm waiting on an order from Futaba for keyed connectors to make a jumper cable to go from FRC-style female leads on their sensors to the Vex-style male leads. Even once I get them, it probably wouldn't be until a vacation break, like Thanksgiving, when I would actually have enough time to start programming an absolute holonomic drive.

You might also consider just doing the integration computationally, based on optical wheel encoders on the drive wheels or drag wheels.

I could of did that, but I just wanted to play around with differential gearing to create a complex mechanical-computer type of thing, just for fun. If I was serious about finding the exact location of the robot, I would have picked something much simpler.

[Sislith]

I'm guessing torque.

[Jared W]

hey

hows it coming?

I'd really like to see a movie of the bot in action.

To see how much faster a bigger motor will be.

I hope next season Vex will release beefier motors for torque or speed.