Does anyone else want to make a robot out of an ATV? How hard can it be? GPS, Laser Range Finder, sonar, compass, etc- they're all off-the-shelf-parts nowadays.
Getting the components would be the easy part. Using them to tell the machine where to go and what choices to make is what made the first DARPA grand challenge a challenge.
what will the robot be used for? RC or aurtonomous? Will it have a rider or any heavy cargo?
I would not do gas/electric set up, i would go strait electric. depending on what your doing with it, you prob wont need super high speeds or to be able to haul heavy loads fast. Jusdging byt the size of your atv and some quick internet research you probaly have a 100cc motor in it. That roughly converts to 5.8hp which is approx 4.3 kw. This mean a 5000 watt electric motor is roughly equivilant.
Now, Optima makes a deep cycle truck battery (anything it he d31 serries). That batt has a nominal voltage of 12 and 75amp hour reserve. That comes out to about 900 watt hours of storage per batt. (.9kwh) Multiply by .8 since you cant realy drain them all the way down..and that gives you 720 watt hours per batt.(.72kwh) depending on voltage of electric motor, you will likley need 36 or 48 volts. I'd go with 48 if you can find it. That requiers 4 batts and gives you 2.88 kwh in reserves. a motor that is 5k will run out of juice in about 34 min. But, you wont runt he motor flat out the whole time. Most of the time you will use 20-40% of that power. only durring acceleration and hill do you use the full power. even if you average 2500 (50%) watts you have over an hour of power. 4 of those batts will run you about 800 bucks and weigh in at 240 pounds. A half way decent 5k gen (from a decent brans name, honda, dewalt, miwalki etc.) is around 2 grand and wihes about the same. The batts are smaller and could be mounted easier. a 5k gen is pretty bulky. Electric motors and batts need very little maintance. Gas gens need a lot. If this was my project, I'd go with a 3-5k electric motor and 4 optima yellow top batts. If you go with 3k motor you might be able to find a 24volt motor and go with 2 batts. (obviosly reduced run time compared to 4 batts and you could still use 4 in a 24 volt system if wired serries paralell.)
just my 2 cents. i think we would have better recomendations for you if you told us the purpous of the robot and how long it needs to run,what it will be hauling/how fast it needs to go.
good luck, keep us posted with how it comes out.
FYI, being new tot he forum, i read a responce and thought it was the origginal poster.....sorry.....
but same question to you, what do you want to do with it?