2008 and drivetrains

[Travis Hoffman]

Originally Posted by MikeDubreuil

I can't wait to see the first Ackermann steering robot in competition

http://www.delphielite.com/modules/g...twg_album=2000

Unfortunately, none of the pictures show the steering mechanism. I could go to our old robot retirement home and take some current photos if anyone cares. I don't think it was 100% truly an Ackermann design, but it did have fixed powered wheels in the back and two steered powered wheels chained together up front.

Ah, 2000 - the beginning of the Extruded Aluminum Era for Team 48, which ended abruptly when we faced off against Team 60 in Florida in 2002....

[pakratt1991]

Ackerman Steering would be really interesting to see, although I know we have tried it, and it has some large kinks that need thought out before hand.

And yes, outback has decided it would much rather sponsor teams then sell the tracks, it would be a pain to be considered a FIRST supplier.

[Chuck Glick]

Originally Posted by MikeDubreuil

I can't wait to see the first Ackermann steering robot in competition

Team 284 did it last year, I'll see if I can find a photo of it.

<EDIT>

[AdamHeard]

ackerman was pretty common in 2003 (or a crab that would drive ackerman during autonomous). A few teams did it in 2007 and I'm it was sprinkled throughout the years since FIRST has started.

[EricH]

Originally Posted by AdamHeard

ackerman was pretty common in 2003 (or a crab that would drive ackerman during autonomous). A few teams did it in 2007 and I'm it was sprinkled throughout the years since FIRST has started.

The one I remember in 2003 was 812.

[tdlrali]

Front 2-wheel drive with casters in the back won't allow you to turn fast, since the rear will break out.

[abeD]

Yea my team in 2003 had 2 steered casters in the front with a 4 wheel drive in the back, it worked pretty well but there were a couple of things i would have changed, and yes you could really fly while turning which was pretty cool.

I can also remember several teams that have employed some kind of steering, obviously all the crab drives, but 16 baxter bomb squad a couple years ago had a tricycle setup with all 3 wheels driven and 1 steered, worked very well from what I remember.

[burkey_turkey]

Originally Posted by lukevanoort

What good is a omnidirectional design if your drivers don't know how to use it?

Heh, this is EXACTLY what happened to us last year - we couldn't drive our own robot! Loks like we're gonna be doing two powered wheels in front, two powered omnis in the back, tank drive, so we can 'drift' around the corners.

[tdlrali]

Before you lock on that drive, think hard about the 'drift'... it wont be pleasant.

[Ed Sparks]

I really think a well designed Ackerman system is the way to go.

I'm lobbying my teammates for:
- Ackermann
- Rack & Pinion Steering
- 2 Speed Single Power Plant
- Limited slip differential

I already have a differential design that is fairly easy to make (I'm currently working on reducing the weight a little) and I like the AM SuperShifter. We're looking at various RC car designs for some practical solutions.

[Neil B]

I don't know. If you're going to go Ackerman you'd better have a good turning radius and some good programming for your controllers. It seems to me that there is a lot of space open on the field (each lane is 13 feet wide) but I also think that there's going to be a lot of robot crowding, especially when robots are extended. It seems to me that Ackerman would be difficult to steer precisely when it's on the opposite side of the field; especially with trackballs that are so big they could potentially completely block the view of your robot. The other issue I forsee is a difficulty in turning around unless you intend to be using reverse (another adventure in steering with Ackerman). I'm not saying it can't be done but it will take a lot of practice for the drivers to get good and precise with their steering considering they have a fixed point of reference instead of one on the object (like in a car).

In either case, it will be very interesting to see what drive trains everyone is using. We're thinking of a 6-wheel drive for this year; power when you need it, maneuverability when you need it.

[rkrynn]

My team is thinking of doing 4wd with car drive as the control does this have any intrisic advantages over tank drive or should we just go with tank drive?

[Ed Sparks]

Originally Posted by Neil B

I don't know. If you're going to go Ackerman you'd better have a good turning radius and some good programming for your controllers.......

Programming should be fairly simple, a pid loop to control steering angle and the Y-Axis direct to the powerplant (ok maybe a rate limiter). I don't see the complexity. Am I missing something?

[Ed Sparks]

Originally Posted by rkrynn

My team is thinking of doing 4wd with car drive as the control does this have any intrisic advantages over tank drive or should we just go with tank drive?

Both basic systems are not very efficient at making left hand turns......

[Karthik]

Originally Posted by pakratt1991

And yes, outback has decided it would much rather sponsor teams then sell the tracks, it would be a pain to be considered a FIRST supplier.

That's great to hear. How many teams has Outback agreed to sponsor? Is there an application process? I can think of a few local teams who'd love have this type of sponsorship.