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#46
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Whats up with slamming the VW engine? If you do the cooling right and keep all the engine tin on there all is fine!
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#47
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I agree with you - Ive owned 10 aircooled VW vehicles over the years - put an external oil cooler , and a good blower on it, and you got the perfect engine for a desert machine
only thing, I would want an autotranny bolted to it. Automating a 4 speed mannytranny and clutch would be wasted time from the real problem that NEEDS to be solved navigation! |
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#48
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no help huh?
I see two options. A) High tech solar powered battery-toting low-riding aerodynamic SOB. Advantages: very cool, very slick. Disadvantages: expensive. Very very much so. And slower than internal combustion engines. B) Heres what I would do (if it fit in the rules). I would buy a pickup or van, a really crappy old one. In the back I would put gas tanks so it could make the trip on one tank. In the drivers seat I would set it up so that it could be autonomous. Think that simpsons episode where Homer and Bart drive the 18 wheeler with the autopilot. You would probably want GPS in there, and you would want pretty sophisticated obsticle detection and road atlas software. Advantages: cheap. ghetto. if you were reckless you could set it up to go 100 mph +. It would be able to survive minor collisions with no work needed. would be really cool to see a truck driving itself. You would have lots of spare cargo space for fun systems like radio PA systems or a video recorder with thousands of hours of tape. Imagine pulling up with an 80's pickup on your trailer, unloading it around all those slick solar cars. You could have fun with the paint job, more so than with those solar ones cause its bigger, and you don't need solar cells on top. Disadvantages: prone to breaking down (get it serviced before you convert it) ugly, loud, 'dirty.' possibility of running out of gas. Bad stuff if you hit someone/something at high speeds. still. I say go with the 'convert-a-beater' method. It would be more fun. You could even make it look like a humanoid, or an alien or something is driving. heh. |
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#49
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In about a month or so, I'd like to picka design and begin working on the technical paper required by DARPA for the competition. Is that ok with everybody?
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#50
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Quote:
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It's far easier to just eliminate the safety mechanisms and focus on the collision detection and avoidance aspect of the vehicle. At 40MPH the vehicle isn't going to survive. Period. Build it lightweight with a carbon fiber body to maximize fuel efficiency. I'd probabaly use a lightweight aluminum piston or rotary engine. The fuel density is just so much greater (by a few hundred percent!) and cheaper with a liquid fuel versus batteries. |
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#51
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DARPA has already stated this course could be driven by a human in a jeep or 4WD pickup (although your kidneys might get bruised at the speed requied through the desert)
so why are people trying to design new vehicles - frames, engines - solar powered?!?! this is not a contest to see who can make a vehicle that can go from LA to Vegas - we already have hundreds of vehicles right now that can easily do it. The 'trick' is to make the vehicle drive there all by itself! this contest is about auto-navigation - piece of cake in an aircraft or sailboat - pretty challenging in the desert or on a two lane dirt road. THAT is where the contest will be won or lost: 1. Naviagtion 2. Navigation 3. Navigation there is no reason to 're-invent the jeep' |
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#52
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I agree that you will get something out of this project even if the car or whatever goes 10 feet but...
I can't help but laugh at all the people who say this is an easy task. Why do you think the military wants someone to build one? (because this is no easy task....) One question how well did your team's auto code work??? Why build a truck that can roll over when you can build a supersize of this? |
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#53
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I might not be a crackerjack programmer, but I'm willing to contribute any coding I can. IIRC you can purchase GPS units that can feedback through a serial port to a computer. An idea perhaps, use a modified version of the StangPS plotting software and a GPS program written to take in the info and map it onto the virtual path, then you can plot the course via computer when preparing for the race. If we can get it to work like 111's auto code, I'd say we are in good shape. I'd like to work with someone on the GPS input side of things, but I'll need specifications, mainly what unit are you using and how does it interface? How does it form the packets of information. Once I have that I'm confident I can (with 111's programming hlep) build a program to plot a GPS course. It won't help with local stuff, but at least it can keep itself in the general right direction :-). So one you decide on a GPS unit, lemme know and I'll try to come up with something.
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#54
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While I agree that this will be no easy undertaking, it is definitely possible, and any contributions at all are welcome. Soon we will have a team website so i'll keep you all posted on team developments.
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#55
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how bout we modify a gas/electric hybrid, then stick solar panels on it. A tank of gas should be enough to do the whole thing, when augmented with an unlimited source of power. then just mount a bunch of sensors on the front so it doesn't run anyone over, tie a GPS system to the controls, and drive the car with servos and pistons (for the petals and steering)
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#56
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I think some of you are missing the point. While you could technically convert a 4x4 to an autonomous device, why would you? anything meant to be driven by humans will be big, will have safety devices which aren't needed, and will have wasted space. Look at nasa. when they want to design a moon rover, they don't convert a commercial vehicale! Nor do firsters take an RC car, swap out some parts and call it a robot.
If you truely plan on doing this (which I think is great, but i'm on the wrong coast), then use a bottom up aproach. maybe not from scratch, but dont just modify someone else's creation. Be creative, dare to use your imagination and think outside the box. small example: lots of ppl suggest putting a large gas tank on the 'bot so it has all the fuel it needs, with no stopping. problem with that is it adds weight, which lowers efficaincy, which in turn requires more gas. if you are allowed to refuel, take advantage of it. it isn't hard to build a homing beacon and put it at the checkpoint (legal, according to the rules). have the bot dock, swap fuel cells/batteries/fill up/whatever and go on its merry way! Also, combustable materials in purely autonomous vechiles is not such a hot idea. pretend the purpose of the bot is to scout out potentialy hostile territory and take that into consideration. anything that can explode is bad! just my .02 |
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#57
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Exactly my point. Although, comparing the weight with the amount of energy you will get out of gasoline, it is by far the best fuel source available. I do see where you are coming from, but until other fuel sources have comparable energy densities, there really isn't much other choice. Gas weighs 6.1lbs per gallon. A heavily optimized 2-3 cylinder piston or rotary engine will average 50mpg easily. You'll only need 8 gallons of gas, which is 40lbs. The weight is good anyways, because if the vehicle is too light you won't maintain traction in turns. The reason why it's better to build something from the ground-up, other than the above, is because then there is less that you have to worry about in the programming. Most SUV's/Trucks have an extremely high center of gravity, and they will tip when taking a sharp turn at 40 MPH, removing you from the competition. Sure, you could use tilt sensors to detect how much centripetal force is being exerted on the vehicle, but then all the more you have to worry about in slowing the vehicle down and such. Remember, that this is a race. Only the fastest vehicle gets the prize. A vehicle with a lower center of gravity will navigate much easier. |
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#58
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I agree with all of you who say that building from the ground up is mo betta'. Also they say the money rolls over if nobody qualifies for it this year, so we can see what type of vehicle does best.
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#59
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Exactly
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#60
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designing this machine from the ground up is a violation of one of the Golden Rules of Engineering:
6. Dont re-invent the wheel! The team that wins this contest will spend 99.999% of their time, energy and resources solving the navigation problem and 0.001% of their time integrating their navigation system onto an existing vehicle. |
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