Atwood and Drill, or at least it's what we did last year. This year we are thinking...
~Mr. Ivey

Hey wetzel, alot of teams do this, they have a primary drive system, and then a secondary (powerful) one, Like CHAOS- 131, they have a tanks system and wheeled, they just engage at different times



look at 157, 237, and 131 for examples


Badjokeguy

BOSCH & FP!!
 

We found the Drill and FP to well compliment each other (important on a swerve drivetrain) on our 4 independent drive modules, especially with the more powerful FP motors this year. We also kept the modules identical left to right so all the motors spun the same direction so that the drill timing was no longer an issue. We used the Chips for the boom that needed alot of power since it wasn't counterbalanced, also they are heavy!! Definately the Drills on the drive they are a perfect fit for that.

Re: BOSCH & FP!!
 

The drill motor has timing. Your kidding. We've been running it in reverse on one side this whole time. Can you elaborate a little more on this.

Drill motors are usually timed for better performance in the forward direction (for drill bits and inserting screws) so it has a little better performance in the forward direction. You could (depending on your robot design) see a slight curve in the driving of your robot because of this. Search the forum for Drill Motor timing, I know we have had discussions on it in the past and ways to correct it.

Matt

Okay thanks. I know runing motors with "negative timing" can lead to excessive heat, arcing, current draw, and wear. So, I'll go look fo those threads.

true 4 wheel
 

For the past 2 years our team has created independantly powered 4 wheel drive systems. In 2001 we used 2 drills and 2 fisher price, but we found that the gearboxes (plastic) kept burning teeth (although they could still run in some instances). In 2002 we used the new chipuas with the same drill syatem we had the year before. It took a while to match the chips to our drills but we got it and it worked fairly well. We never had any overheating problems because we hardly ever moved (lol stradegy always wins). We did notice however that the draw from the drills and chipuas was rather taxing on our batery. Because of this we opted for no pneumatics.

To date we have never worked on our 2002 bots drive train, and only a few post competition events have we had to change our our 2001 bot's gearboxes and one fisher price we burned out (the sleeve on the motor came back and covered the eexaust holes in the back and well lets just say the magic smoke came out).

the drill motors have 15% more power and speed in the forward dirrection, than they do in the reverse dirrection, last year (2002) we put both in the same dirrection, so we were able to go 15% faster in forward (the dirrection our tranny was designed to go) than we did in reverse. we also used the atwood in there to give it plenty of power

Re: BOSCH & FP!!
 

Hey- I've heard about swerve drivetrains and last year I saw Chief Delphi's bot- man did it ever drive sweet.. I've never heard any logic explaining how it works- could someone explain it to me or link me to a page.. Thanks..

Re: Re: BOSCH & FP!!
 

In a 'swerve' drivetrain each of the 4 wheels has the ability to pivot in the vertical axis. So far, Chief delphi (6 I think) holds the record for the most complex setups including the fully independent 4 wheels steer setup in 2001 using traingle tank treads where each of the 4 could pivot independently of each other. For our first attempt at 'swerve' last year we linked all four drive modules to each other so they pivoted together. Then you place a pot on one of them to pick up position. We converted the rectangular coordinates from the joystick to polar to get a vector that we wanted the wheels to point to. When it is all said and done a 4 wheel steer robot is extremely manuverable and can get out of very tight spaces. We took it a step further and made the drive modules easily replaceable or 'modular' an approach everyone should look into doing after we noticed the modules on wildstang 2001 and how they had spares ready to go in just minutes. For more info, I posted our gearboxes in the whitepapers and the full code for the steering on the Codex and various places on this site under the name pegasus.zip

Happy swerving, many teams can help you on this but each of us has a few secrets up our sleves :D

Re: Re: Re: BOSCH & FP!!
 

Thanks for explaining- unforunately I don't have any CAD programs at home so I can't access that .dwg file you had on the white papers.. Anyone have a pic I could look at?

Don't worry- I'm not part of the pit crew here and I'm also not spying for anyone.. Just a curious firstaholic here..



P.S.- That's a nice H2 you're in... sighs...

A good program for any of you at home for free is VoloView from Autodesk it lets you open and zoom in DWG files without having to buy a CAD package. YOu can not make changes but you can view them.

4 Atwoods!!
 

For 2002, we successfully used 1 Boesch and 1 Atwood geared to a common output. We geared the motors so that each were operating at 75% output. We never had a problem over heating the drills or the Atwoods. Accelleration was over 10 ft/sec when in high gear, and in low, gave us plenty of grunt to push or pull a few of the big dawgs around the block without overloading the motors and tripping the circut breaker. Depending on what tasks we will need to do in 2003, we will be able to tweak the gearing for higher torque or accellaration over 18 ft/sec. Of course I think it would be cool to have the bot do a big wheelstand as it launches out of the hole and throw out the laundry on the big end...but this is not drag racing....?:D

Just a thought ---- Did the winners of last year's Nationals have complicated 2 or 3 motor drives, or did they have simpler, more robust 1 motor drives geared appropriately, and driven well?

The 255 robot (2000 national champ) had 4 motors on the entire robot. FP for the 2 wheel drive, a van door to raise the basket/lift the robot, and a seat motor to open and close the baske door. Strategy, driver skill, reliability usually beat complex drive systems.

So stop bad mouthing the FPs - they will work fine for the Rookies.

I liked the FP's especially last years, they had great power and better cooling. We used them in the drivetrain also.