Which pneumatic cylinder model will be best for robot fight and push 30KG easily??

I wanna a poweful pneumatic cylinder which can push fastly 30-50KG easily. I want this cylinder for robot fight (But not big pneumatic cylinder max. weight of pneumatic cylinder should be 1.5KG. cause robot has weight limit. i wanna buy this cylinder form online shop ( Like ebay,amazon,hobby king etc. good online shop). But i haven't good knowledge about pneumatic cylinder. So if anyone have good knowledge about pneumatic cylinder then please recommend me a good one for robot fight with all equipment ( solinoid bulb, fitings). Give me the proper goof online shop link where i can buy this pneumatic cylinder.


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Downunder35m3 months ago

I had a look at different setups, cylinder sizes and air pressures....
With the restrictions you have in mind I see little to no chance to make it work.
Even with a CO2 tank and the pressure set to the operating max of a standard cylinder you will be over your weight limit.
Tank, high speed valves and fitting alone already go over 1.5kg if you need more than a few seconds of operating time.
I think a better approach would be a spring and a geared motor with a clutch.
Motor pulls your spring loaded lever down and when you need to punch it the clutch and locking pin is released.
With the right sized motor and gear box you will stay well below the 1.5kg mark but you might have to compromise on the retracting speed depending on motor and gearbox.

Takrim (author)  Downunder35m3 months ago


Is this model good enough to push 20KG easily. Can i make my whole robot with co2 cylinder ,piston, vulb within 10KG?

Jack A Lopez3 months ago

You will make the math easier for yourself if you can consider your force in newtons, the distance through which the arm must push in meters, and the time in which this action must take place (i.e. how "fastly" the push must happen) in seconds.

If you do that, then you can calculate how much work, and power, is needed for to make your robot push things around.

Also it seems like there should be a simple relation between the area of the piston in your cylinder, the air pressure behind it, and the force this air places on the cylinder, namely

F= P*A

a pascal is 1 N/m^2, and 1 megapascal = 1 MPa = 10^6 N/m^2 = (10^6 N)/(10^4 cm^2) = 100 N/ cm^2

From what I've uncovered so far, typical allowed air pressure for these robot tournaments is around 0.5 MPa, or around 75 PSI (pounds force per square inch). So you know, that works out to like 50 N of force per square centimeter of piston cross-section.

I dunno. The amount of force you're asking for, 300 to 500 N? It seems kind of heavy compared to what I have encountered in my search results so far, for "pneumatic cylinders for robots"


but maybe not impossible.

Takrim (author)  Jack A Lopez3 months ago


is this model good enough to push 20KG easily? HOW Co2 cylinder gas should i need for running pneumatic piston for 30min.

I am guessing you are planning on using some kind of portable CO2 tank plus gas pressure regulator, like this one:


This kind of thing is light enough you can wear it on your hip, yet ostensibly powerful enough for the usual compressed air tools and tasks, like air powered nailgun, filling car tires, etc.

It uses the same CO2 bottles as those used for CO2 powered paintball guns.

I am not sure what is required for the valves. This link (to "1/4 NPT 3 Way 2 Position Pneumatic Electric Solenoid Valve DC 12 V") is just a guess.


Note that the pressure on the high side of this regulator is really, rather high, like 60 atm, or 800 PSI, (using the approximation 1 atm = 15 PSI) whatever the vapor pressure of CO2 is a room temperature, so this thing would be really interesting without the regulator, if you could find valves and cylinders that would work at 800 PSI !

However, the usual, typical air tool is only rated for 100 PSI, or 150 PSI? Something like this. Also your robot fight might have its own rules regarding gas pressure in its contestant's pneumatic actuators. Some numbers I read for this were, 60 PSI, 75 PSI, ( or 4 or 5 atm, again using the approximation 1 atm = 15 PSI) I came across those numbers, I think, in pages from that first search that I did, for "pneumatic cylinders for robots", linked again here,


The calculations for force exerted by the piston, amount of gas used per stroke, etc, all depend on a number for gas pressure, and like I did last time, I am going to just guess that P = 75 PSI.

In other units, this is approximately:

75 PSI = 5 atm = 500 KPa = 0.5 Ma

Recall that F = P*A, and that with a pressure difference of 75 PSI, that was about 50 N per square centimeter of piston cross section.

The cylinder-piston thing that you linked to today,


claims to have a bore of 2.0 inches and a stroke of 6.0 inches. So the pistion cross section has an area of (3.1416*)(2.54^2) = 20.268 = 20.0 cm^2

Multiply that by 50 N/cm^2, to get:

F= (50 N/cm^2)*(20 cm^2) = 1000 N

Which is roughly enough force to lift 100 kg. That is using the approximation 10 N/ kg, which comes from the value for "little g", on Earth, around 9.8 m/s^2 ~= 10.0 m/s^2

That seems like a lot. This might be one of those, "have to see it to believe it", situations. I mean I think the math is right, but seeing it happen would give me more confidence.

Regarding the question of how much gas is used per stroke, just multiply the volume of one full stroke, i.e. (20 cm^2)*(15 cm) = 300 cm^3, times the density of the gas in this volume. To estimate the density of the gas, I just used the ideal gas law ( P*V = n*R*T) and a value of 44 g/mol for the molecular mass of carbon dioxide. Recall P and T in that formula are absolute. I used P= 6 atm, and T = 300 K,

and R= 8314 cm^3*KPa/K/mol


and the answer I got was about 0.072 mol, or 3.2 g, of CO2 gas per stroke.

And how many grams of CO2 does the bottle hold? The quotes I see for bottle sizes are in ounces (oz) of CO2, like {10 oz, 16 oz, 20 oz} which at 28.4 grams per ounce, works out to {284 g, 454 g, 568 g} in grams.

Dividing each of those by 3.2 g, gives, {89, 142, 177}

So, what, like 100 strokes per bottle, approximately?

Although, that number, for the gas economy, will not be as good if the gas coming out of the bottle is cold, because cold gas is more dense, so you would use more of it per stroke of fixed volume. You might want to recalculate using lower absolute temp, T. Still, this seems like a large number of strokes per bottle of CO2.

I'm honestly not sure how many punches are required for a typical robot fight. ;-P

Takrim (author) 3 months ago


Is this model good enough to push 20KG easily. Can i make whole robot with co2 gas and pneumatic cylinder within 10KG?