hmm… i wonder what i can do with that 4 hp engine i have…
suggestions? maybe it’ll be the next cool hack
its a 4 hp briggs and stratton upright 4 cycle lawnmower engine

Posted at 4:05 pm on Sep 21st, 2007 by Frogz

I saw this in the fall issue of robot magazine. Neat little idea for powering a robot.

Posted at 4:08 pm on Sep 21st, 2007 by tom61

Pretty cool robot does solve the battery life problem even though it’s a little noisy.
I been thinking on doing a very similar setup using an 8 hp briggs and stratton .

Posted at 4:09 pm on Sep 21st, 2007 by Membrane

I’ve often thought about using a gas>electric scheme like this project to power a robot. Unfortunately, they always tend to be less powerful than a direct mechanical drive and usually just as hard to to implement.

Posted at 6:26 pm on Sep 21st, 2007 by Greg

On Robot Wars they had a robot called 4×4 which used a 2-stroke petrol engine and full hydraulic drive, which makes very efficient use of engine power. Too bad it broke down in the middle of a fight, though.

Posted at 7:11 pm on Sep 21st, 2007 by js

Oh, and btw a Ryobi/Troy-Bilt four-stroke should work just as well, especially the new Robin-designed 29cc version.

Posted at 7:16 pm on Sep 21st, 2007 by js

@ greg. i would figure this is a lot easier to implement then a mechanical. You don’t need to worry about a clutch or the like. With electrical motors on the wheels you can direct drive, eliminating extra axles and gears and whatnot. Also with electrical motors you can implement electrical breaking and avoid another mechanical component. Speed control would be simpler and more pierce. With motors on either side of the vehicle you don’t need a steer wheel when you control their speeds independently. As far a power, electrical motors have more torque at lower speeds than a conventional combustion engine.

Im not trying to be a jerk just giving my opinion. Also im an electrical guy so all this stuff sounds easy to me, and you may be a mechanical guy so maybe a pure mechanical system would be simpler for you.

Posted at 12:42 am on Sep 22nd, 2007 by chupa

why isn’t a speed doubler used to get more RPMs into the alternator? Since its charging batteries and not directly responsible for the motor load, it shouldn’t suddenly increase or decrease load on the engine; it would be a pretty smooth curve that the engine could probably handle easily.

Alternators don’t really become useful until they reach a certain RPM, and they only gain efficiency until you reach the threshold of the voltage regulator.

Posted at 1:20 am on Sep 22nd, 2007 by jeremiah

it’s closer to ‘diesel electric’ than ‘hybrid’ – the ic engine isn’t connected to the transmission, just an alternator

‘campsite battery charger on wheels’ might be a little closer to it

Posted at 10:39 am on Sep 22nd, 2007 by jim

I’d bet that if a very effecient gas motor, coupled with a very effecient electric generator, could be used very keenly to replace even the largest of batteries in robots… If that gas motor was made to run at peak effeciency, and there was something like a large capaicitor in the mix… The possibilities could be endless!

I wonder what kind of output that provides, compared to a Li-Ion or SLA cell of equal weight :-D

Posted at 11:12 am on Sep 22nd, 2007 by Wizzard

Very Efficient and Gas Motor don’t belong in the same sentence

Posted at 12:47 pm on Sep 22nd, 2007 by adaminc

It would require yet more heavy hardware, but would make the most sense to implement a starter. i mean, the whole idea is prolonging operational time. no sense running that engine while the robot is sitting around waiting on data. the average robot is not constantly moving. So, when the battery runs low, start up the motor, charge it pretty fast, then shut it off again.
15 minutes of battery life or 15 minutes of gasoline, is still only 15 minutes of run time! with an automatic starter and shut down, 15 minutes of gas and 15 minutes of battery is more like 25 minutes run time.

Posted at 3:39 pm on Sep 22nd, 2007 by MRE

It would be really cool if he ran that off propane or some other alternative fuel.

Posted at 9:06 pm on Sep 22nd, 2007 by Computer_kid

Very nifty, though I shudder to think of the pollution your average small mower / weed eater / etc. gas engine produces…

Posted at 9:35 pm on Sep 22nd, 2007 by smilr

This can allow people to make bots like in the game Bioshock! Gas-powered machine-gun turrets and helicoptors (also with machine guns of course).

Posted at 10:48 am on Sep 23rd, 2007 by factor grimm

how hard would it be to make this feasibly powered by propane using this info?
http://home.earthlink.net/~lenyr/pplmwr.htm

Posted at 5:02 pm on Sep 23rd, 2007 by terminalblue

This is a very interesting project!

I built a battery-powered wheeled rov that lasted over ten hours in the field with a 25ah battery.

the addition of a system like this could make for some very very long running times, but I agree the motor should have a starter on it so the engine can be stopped and started as needed.

The machining on that base is beautiful.

The guy works for parallax too, which is a great company for microcontrollers and some nice folks too.

very very cool

Posted at 6:40 pm on Sep 23rd, 2007 by strider_mt2k

Propane, a fossil fuel, why? The days of it being a lower cost alternative to gasoline for motor vehicles are over. The concept of an ICE directly driving an auto alternator is nothing new, but this implementation of is is close to art.

Posted at 2:08 pm on Sep 24th, 2007 by static

Yes..this is just the way that everybody want

Posted at 6:38 am on Sep 27th, 2007 by Allison

i doubt he wanted to use propane to try and save some money on running his robot, probably because of the emissions compared to gasoline. if it ran on propane you might be able to use the thing indoors. just like warehouses usually have a propane forklift to use inside.

Posted at 8:56 pm on Sep 29th, 2007 by luke