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DARPA Grand Challenge race, Tahoe mechanical advice needed!

Discussion in '1992-Present Chevy & GMC models' started by Blazotron, Apr 18, 2003.

  1. Blazotron

    Blazotron Newbie

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    Hi all,

    Not sure where this post should go exactly, maybe the moderator can move if necessary.

    I represent the California Institute of Technology (Caltech) team planning to enter the DARPA grand challenge. Basically this is a 1 million dollar prize race put on by DARPA from Los Angeles to Las Vegas (about 250 miles) to be completed in 10 hours (if you were wondering, the prize would be donated to education, if won). Sounds pretty easy? The catch is that no person can be in control of the vehicle, and you only find out what the exact route is about 2 hours before the race. Every aspect of the race, from route finding, obstacle avoidance, steering, braking, accellerating, and tons of other stuff has to be done by a computer. This is not remote control; this means that when the green flag goes, the vehicle starts on its own and hopefully it shows up less than 10 hours later in Las Vegas. Take a look here for more information.
    http://www.darpa.mil/grandchallenge/

    The Caltech team
    http://www.cds.caltech.edu/~dvangogh/GrandChallenge/
    is currently made up of some 60 undergraduates (about 7% of the school's students!) and 15+ advisors from Caltech, JPL, and industry. We have good shot at this contest and we are working hard on it. That being said, I am working on the mechanical team and we are responsible for vehicle selection, modification, sensor mounting, actuator mounting (on the steering, brakes, etc) and integration, and other mechanical aspects. First things first, we are trying to decide on a vehicle before friday the 25th of April. We are settled on a GM product, and we have to have a modern vehicle (like 96+ unfortunately) because the sensors that are already mounted (like wheel speed, oil temp, stc) will be going directly into out computer system. So, we are pretty set on a Tahoe.

    As you can understand, the mechanical aspects of this vehicle have to be absolutely bulletproof. If they fail, the whole thing is over. So, we need tires that won't go flat, u-joints that won't break, good suspension, you name it.

    My question to everyone here is what do we need to do to this machine to make it indestructable. Note that we plan to lift it about 3 inches and put bigger meats on it (33's?). But we are not rock crawling, so it just has to be able to handle what you might find on a desert road. We don't need (or want) a super truck that can do amazing things, but is prone to breakdown. We want a truck with parts that we can guarentee as much as possible that will not fail for the 250+ miles of the race.

    So, what are your ideas? What should we buy? Anybody got parts(money?) they want to donate? (We will probably be able to put a logo on the vehicle.) Who makes the best lift kits, tires, alternators, whatever?

    Lets hear it.

    Thanks
    Will Heltsley
    Junior, Mechanical Engineering, Caltech
    92 Chevy 1500 Longbed
    76 GMC Jimmy
     
  2. AJMBLAZER

    AJMBLAZER Better to be lucky than good. Premium Member

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    Re: DARPA grand challenge race, were using a Tahoe and we need advice!

    DON'T LIFT IT. Put some 285/75R16 (33x11.25R16) tires on the stock rims and go. Maybe some 305/70R16 (slightly shorter 33x12R16) tires on the stock rims. Won't rub and no messing with GM IFS. I had a 2-3" Rancho lift on my 92 Chevy Blazer K1500. It sucked. Many steering issues and the ride was terrible. Virtually no travel up front. Would suck to find out your truck didn't finish and find it half way there with a broken steering component or something due to the crappy lift. All of the 2-3" GM IFS lifts are very similar, so I'd say give it a big NO. You can fit 33's stock, so screw it, leave good enough alone. At most, put some Bilstein HD shocks ($50 each at AutoZone) on it and call it good.

    BFGoodrich makes tires in both of those sizes, and with their 3 ply sidewall, that would be the tire I would choose for this. Maybe the Goodyear MT/R also. Definately a tire with the 3 ply sidewall. Don't want a cheap tire going out on you either.

    I could see maybe a higher amp output alternator since you'll have some computer stuff to power, but really, the stock 105amp or so alternator should be fine. At most, the biggest one you can find that bolts on from NAPA. If I recall, the Vortech alternators aren't as easy to change as the older ones.

    Wow...........first time I've posted here in a while. Hope this helps./forums/images/graemlins/tongue.gif
     
  3. willyswanter

    willyswanter 1/2 ton status GMOTM Winner

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    Re: DARPA grand challenge race, were using a Tahoe and we need advice!

    Cool, I've been following the Darpa challenge since it first came up! Can't wait to see the thing run... I've been messing with autonomous stuff for years but nothing on that large of a scale.

    Good luck with it /forums/images/graemlins/thumb.gif

    Anyway, don't go larger than a 33" tire as stated above. The factory independent suspension in front and the 10 bolt rear would really not like that...

    I'll dig out the paperwork but I have the info on the system used by GM Defense on the new cucv style trucks for the auto tire inflation system and run flats. You may want to look into this because it's electronicsally controlled which could easily be integrated into the cpu where you could automatically lower tire pressures when you get off the paved highway making for a smoother ride, less harsh on components, and will give better flotation.

    I'll come up with some more stuff here in a bit...
     
  4. Blazotron

    Blazotron Newbie

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    Thanks for the advice, guys. Keep it coming. What about reliability issues. Anything that tends to break on these vehicles and needs to be replaced?
     
  5. 89K1500Chevy

    89K1500Chevy 1/2 ton status

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    I would recomend going with a tire made for sand and rocks b/c youll be out in the desert. Id think something along the lines of Procomp like the Xterain or mabey a M/T Baja Claw. I think Procomp might go in on this they like to sponsor a lot of stuff. Prob want to put some kinda bumper like the Warn Classic or one from Offroad Designs that way you get a higher bumper to ground clearnce up front and the tires wont be rubbing on the bumper b/c belive me i know that some 33's on a stock ifs will rub on bumper and prob the back of the wheel well. For some 33/12.50s youll need wider wheels or your tire will rub on steering componet's. Also look into BushWhacker Cut out fender flares. I would say since this is a truck that is for offroading and on a 10 hour or less run Tighten up a little on the T bars to get some front end ground clearnce and mabey some 2in lift blocks in the rear. That way you wont have to worry about tires rubbing under flex or turning. what are you planing for body armor? like if the robot drivers have road rage and ram your truck? An Exo Cage? /forums/images/graemlins/truck.gif /forums/images/graemlins/usaflag.gif www.zombieoffroading.8m.net
     

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