Making Inmoov autonomous

Hi, I don't know if you ever addresed this problem but as long as Gael is now working on the legs (yes Gael, I do agree with the rest of the community, Inmoov must have legs, no wheels please) it will soon appear the "need of power" problem.
Self balancing on the legs will introduce power drainage problems and unless you want to have your Inmoov running on lead batteries for only 3 minutes before they get drained by the many servos or to keep it hooked on a power cable, an alternative solution must be found.
The clever guys at Boston Dynamics came out with a brilliant idea: at least for the outdoor situations, provide a gasoline powered generator built whithin the robot body.

In this view, have you ever thought to implement a self built power generator, using one of those micro engines from the hobby market (typically for RC toys), attached to a dynamo, then to a power converter, then to the battery packs so to keep them constantly charged?

I guess a small engine with half a litre of gasoline, might keep Inmoov up and running for at least one hour. The weight could be estimated being well within the 3 Kgs and such small components could be inserted either directly in Inmoov's body or better, on a small Backpack which he could vest when needed.

An engine like this for example weights only 627 grams. It has 1,2 hp which is more than enough to generate all the needed power.

Add to it 500 grams of gasoline, another 200 grams for the dynamo, 200 grams for and eventual gearbox, 1 kg for an aluminum backpack (cannot be printed, the engine is hot) and here you have the whole setup weighting well below 3 kg and being capable to generate at least 500 Watts/hour.
This is because direct conversion says that 1.2 hp = 895 watts/hour. Take into consideration the loss introduced by the gearbox and the dynamo and you get down probably to 500 watts/hour, which would be anyway more than enough to keep Inmoov alive and kicking.

If you think carefully, this solution is very simple, cheap and easy to build.


GroG's picture

Sure it makes sense. My

Sure it makes sense. My mantra is always WE NEED MORE POWER !   In the past I've looked around for "mini gasoline generators" - a sort of all in one combination, which has your gasoline motor, generator and electronics all in one package 

This one is supposed to be "ultra quite" which might be a nice feature

Buying an all in one solution sometimes will save you money and time buying the parts individually - If the output is AC with no DC options the electronics can be hacked or if your preference is to buy parts you can get a AC -to-> DC converter.


RobertoPreatoni's picture

Yep, I thought about that

Yep, I thought about a similar portable unit at first as well, but those things a way heavier and also pricey than a diy solution. That unit itself weights 8kg, plus the gasoline. I guess that if we are thinking about a sort of backpack, having almost 10kg instead of 3 at that height, might seriously effect the overall baricenter, raising it by a lot, thus ending in having the robot continuosly over-reacting to maintain it's balance.

The lower the baricenter, the less work will have to do the servos, the less energy will be consumed, the less wear and tear will effect all the mechanics/servos. In fact, the best would be to have that unit close to the floor level, but that will make the aesthetic a living nightmare.

But it is anyway a solution worth to explore.

GroG's picture

Fanny Pack Generator !

Just need it a bit bigger - keep it low for lower center of gravity :)

RobertoPreatoni's picture

Uh nice, he could fit also a

Uh nice, he could fit also a sandwich in it...

JCInMoov's picture

why not have a small built-in

why not have a small built-in gas tank inside his torso to hold the gasoline (or the generator) since there aren't a lot of components there? it would greatly help with stability since it is directly above his COG instead of a backpack which would throw him off. 

Just my two cents though, I'm still a noob :/ 

cyberhedz's picture

I like, but

this is a great idea, but I would like to make some improvements/suggestions.


using something like these hard backpacks (, and then dynamatting the interior could reduce the sound.  I'm not sure if you've had one of those engines, but they can be LOUD.  Also, instead of a chest tank, how about several bladders running down the legs, something like these fuel cans for camping (, would be gasoline safe, and you can either use a small pump, or gravity feed.  If you go with a small pump, you cold just put these bottles in the water bottle holder included in most backpacks. The backpack would only need 3 mods, a QD fuel line port, an exhaust port, and an electrical connector for the inmoov.