Team 871 - Homebrew Segway

[DanLevin247]

With the platform below the wheels....when you start moving, the front of your'e platform will dip down upon acceleration...correct? If you correct this initial lean by compensating in the opposite direction wouldn't, a pendlious action occur...rocking back and forth as the rider tries to maintain ther own balance? This act of acceleration would cause you to lean even further foward before you had a chance to compensate...and if you had true segway like function...go even faster?
If you had your'e platform on top of the wheels, I think it would be harder on the gyro, but easier to maintain balance upon acceleration.

[D.Fahringer]

The deck dips down in front in advance of going forward not because of it. A gyro or manual Segway has to tilt accordingly to the amount of acceleration required. This would happen by the way even if your Segway has it's platform over the axles.

Yes, the Segway has its platform well under the axle line and although it is harder to make them like this it is for good reason.

The heaviest things on it are at the lowest possible position...that is the batteries, then the motors and the aluminum casing etc.

If they were trying for a high CG they would have put the batteries in the steering stalk like the batteries in a flashlight.

I finally made a dv .mpg clip of the KnightKrawler at it's VCU debut. (I apologise for the poor quality animated gifs) I wish it were lighter but you can adjust that I hope. I'll make a link to it soon.

The pendulous action yuo describe certainly can happen on our machine as a result of over correcting and in the case of the Segway as a result of a new rider not trusting the stablility of the machine. I will say that in both cases it is experience and anticipation that will fix that problem for the most part.

Looking at the Video from March 2003 of me on that knightKrawler I can say I am smoother than that now!


And a Segway with the base over the axles will probably be fine provided there is power to make it work for a more novice rider.

[sanddrag]

Originally posted by D.Fahringer
The pendulous action yuo describe certainly can happen on our machine as a result of over correcting and in the case of the Segway as a result of a new rider not trusting the stablility of the machine.

Oh, yeah. I remember that from the first time I got on the Segway. As long as you relax you can pick up the feel for it in only a couple minutes. Then the machine moves precisely as how you would want it. Ah, what memories...

[MrB]

yep, i was wrong.. for some reason i thought the deck was higher...

[D.Fahringer]

Here is the only DV Mpeg of our KnightKrawler debut at the 2003 VCU event, the video software doesn't have a working provision for lightening the picture....it came with the capture card.

If anyone has a video of our KnightKrawler it might be worth a Team 122 Omniwheel Pendant! If you have the video of Dean Kamen riding our KnightKrawler at VCU, it is worth THREE pendants!!!


Check out the video....KnightKrawler Debut at VCU

http:/wihs.zapto.org/~knightkrawler/

[MrB]

that is a nice clip... and out of curiosity, what are these pendants that you speak of? They sound like a prestigious prize :-)

[D.Fahringer]

Thanks! And yes the Omni Badges are cool...any color bead you want too! The omni rollers actually spin also!

[Willum]

I put up a little insight to what i'm thinking about the center of gravity on the website. Pardon the connection problems you may have the server isn't 24/7 (it's my personal pc).

I'm trying to post as fast as possible, but i've spent the last 4 days running between prom and graduation parties. It's been nuts!

Will

[MrB]

WOW, that pendant is pretty nice...


Makes me wish I had the video clip your looking for :-)

ok, Willum back to CG

[D.Fahringer]

Here are team 471's segways, two different prototypes, one is controlled with a central joystick and the other uses two drill housings for speed control. They move around pretty quick
with those FP motors, and you can hear them comming because the motor gears make some noise. They have casters on the back now, but I think they were originally trying a tilt switch balance system where the motors would be compensating for the tilt of the base due to a smooth teflon slipper switch mounted under the platform that would ride on the floor.

[Matt Krass]

Oh hey this thread is still here good. I had an idea for my solution to the sloppy drill problem. I'm gonna try this whether or not you guys like it but I'd like an opinion. Also, much thanks to Andy Baker for this idea (in other words, if it blows up and hurts someone blame him! ) Anyway, since the drills have the power I need to move this thing and the FP are tight enough for the balance I was thinking about joining them. Basically both motors with a sprocket on an output shaft leading to a loose shaft for lack of better words. Chains link them and I think I can play around with the ratios to get the RPM close enough. If it works then I will have a sprocket take the output and chain it to the wheels. The idea is basically the FP will keep you steady with the Bosch throwing in horsepower so you wont be crawling. Any comments? and keep in mind even if this is a doomed failure I'm still trying, I'm stubbornly optimistic plus I need an excuse to get myself to learn ratios and the like.

[sanddrag]

You would definitely have a quite powerful machine. However, chaining the output to the wheels would give you a lot of unwanted play (or little play and excessive chain tension). The best way I've found so far is to just make a custom drivetrain for the Chias. Or just settle for less power an use the window motors (but not the new ones, they get to have 45 degrees of play after a bit of use).

[D.Fahringer]

Not a bad idea...and you could mount a dual chain tensioner.
This is why these forums work so well...ideas can just flow out
and help everyone who participates. Get going Matt, build it, it'll be fun and you won't regret it. And you ask for comments...one I could give is that when you settle on a matching gear ratio between the two motors, consider that the top speed matchup is not that important unless you are making a four wheeled "segway" because you seldom will reach top speed. This is because you need to hold some speed in reserve to make tilt corrections as you ride.

Can't fix the slop in the drill motor? I take it that the drill motor you are using is the new one then? Is the clutch different in it?

[Willum]

I'm begining to think that i'm the only graduated high school senior crazy enough to try and build a mostly functional self balancing robotic scooter.

Is there any knowledge of any other teams trying to do this, or is everyone just building segway look-alike's???

[WernerNYK]

The J-Way as seen (and built only the night before) at Nationals. Sorry, it's the best picture I have. J-Way v.2.0 is expected to have balancing and speed controlling capabilities

Now, WHEN J-Way v.2.0 actually is developed, well that's another story...not very easy to find time when FIRST is a full-year program.