Pneumatics


With a thunderous clap the skies grow dark and the air grows thick at the sound of the word: PNEUMATICS! Scary stuff? You bet! PNEUMATICS ARE VERY VERY DANGEROUS. Don't screw around with this if you don't know what you're doing! When a gas is compressed energy is stored in it in a similar way to a spring. This energy is preferably released in a pneumatic cylinder (which is basically a bicycle pump in reverse) and then stuff gets moving. A hammer is flung or a lifter is sprung and people get running. The scariest pneumatic bots are Toro, T-minus, The Matador, and The Judge. The first three can throw their weight (340lbs, 120lbs, and 220lbs respectively) over 5 feet into the air and even higher. The Judge has a hammer that when fitted with a steel spike can pierce 1/2 inch aluminum. Very scary.

"But Dan! I wanna be able to throw a 220 pound chunk of steel over the fence!" Fear not, citizen of earth, Team STUPID to the rescue!
Stuff you Absolutely Need
What is it? What's it do? Why do I need it?
Tank Stores your gas at high pressure. It's where all your gas is.
Regulator Reduces the pressure from the high pressure (800psi for CO2, 1000-2500psi for nitrogen or air) to a lower pressure (usually 150-250psi) for your pneumatic components. The battlebots rules state that any pneumatic system running over 250psi needs a high-pressure pneumatic waiver. Plus anything over 200psi is very dangerous.
Valve Redirects your regulated gas to your cylinder. Generally come in 2 flavors: 5 port 2 position and 3 port 2 position. A 5 port valve will redirect gas to the "extend" port on the cylinder while at the same time venting the gas already in the cylinder and vice versa. This allows the cylinder to have power going in both directions. A 3 port valve will either let gas into the extend port or stop the flow and vent the gas already in the cylinder. You need a spring or bungee cord of some sort to pull the cylinder back but it saves on the amount of gas you need. Not reccomended for a hammerbot. Generally you want a Solenoid actuated valve. A solenoid is a kind of electromagnet that physically moves the mechanisms inside the valve so you can work the whole job by remote. Valve flow rates are generally marked in Cv, which to be honest involves some really weird math to figure out how fast your cylinder will actuate. Just know that higher is better. Strange Brew's valve has a Cv rating of 2.2 You can't sit on top of the bot during the fight redirecting flows of air. That's dangerous!
Cylinder A big tube with a stick in it that's powered by gas. When gas is put in the back, the stick shoots out, when gas is put in the front the stick pulls back. The force of the cylinder is equal to the area of the cylinder times the pressure so it goes like this: the area of a circle is pi*r^2. r is radius and the radius of a circle is half the diameter. If you have a cylinder 2 inches wide, the radius is 1 inch. 1 squared is still 1 and 1 times pi is pi. Pi is approximately 3.14, so the area is 3.14 square inches. Multiply this by a pressure of 100psi (pounds per square inch) and we get 314 pounds. Most cylinders (and valves) are rated for 150psi. For the most part you want 3/8th inch ports or above to get as much air into the cylinder as quickly as possible. This is what shoots out when the valve hits. Wind isn't gonna hurt the other bot very much...
Tubing Tubing is the veins and arteries of your pneumatic system. You want to use the largest diameter tubing as is feasable to get the highest flow rate, but remember that you can only get as much gas through your system as the lowest flow component. The low pressure stuff is usually PVC, nylon, or polyethelene, and the high pressure tubing is stainless steel. Telekinesis isn't terribly great at controlling airflow. You need this stuff to move your gas around. Think of it as pneumatic veins.
Shut off valve It turns your system on or off manually. Required by battlebots rules and regulations. MUST BE MANUAL. No electronic shut-off valves are allowed.
Purge Valve A normal pneumatic ball valve on a T junction to the normal flow. when this is turned, it vents all of the gas in the system. Rules state that pressure must be releived for the bot to count as deactivated and thus safe to remove from the battlebox.
Pressure Relief valve A thing you put in a T to your regulated gas so that if by some chance the gas pressure rises above a certain level it will be released. Some have a spring that simply can only hold so much pressure other are simply a disc that blows out and releases all pressure in the system. Required by battlebot technical rules and regulations.


What's that you say? You've seen MORE stuff on robots than just what you see here? Well above is just the bare essentials! Below are all the fancy dealies people put on to make it all work better.
Fancy Stuff
What is it? What's it do? Why is it good to have?
Buffer tank Stores the gas from the regulator (whose flow is very low) to release quickly when the valve is opened. Allows for faster, more powerful shots.
Quick exhaust valve Exhausts gas directly out of the cylinder instead of having it go back to the valve. If the valve is the lowest flow part of the system, it still allows for quick acuation.
Valve Pilot Uses some extra gas to help actuate the valve. Because more power can be used to move the valve mechanism, much larger volumes of gas can be actuated, thus the cylinder can actuate faster.

Now the whole shebang put together. This is roughly the setup and arrangement of parts we did in Strange Brew for Battlebots season 4.0. By the numbers now, children!


1. High pressure CO2 tank (20 ounce)
2. Shutoff valve
3. Paintball regulator
4. Purge valve
5. 1/8NPT to 3/8NPT converter
6. Pressure Relief valve.
7. Buffer tank (16 ounce paintball tank)
8. 5/2 valve with 3/8NPT ports
9. Exhaust ports
10. Cylinder (2.5 inch bore, 10 inch stroke)
11. Retract port
12. Extend port

Now like I said this is dangerous stuff, so don't go screwing around with it if you don't know what you're doing!

For season 5.0, Strange Brew's weaponry system looks a little bit different. I'll walk you through this one a little bit closer.

It all starts with 1, the high pressure tank where liquified CO2 is stored at about 800psi. This elbows into 2, a brass ball valve used to turn the system on and off. From there it passes through a length of hydraulic tubing and into 3, a T-connection that has a high-pressure gauge so safety inspectors can read what the in-tank pressure is. It is then angled into the most significant upgrade of this year, 4, the victor sr310 super high flow pressure regulator where the pressure is reduced from 800psi to 150psi. Then to 5, another T junction where the low-pressure can be read and also redirected to 6, a t-junction with another ball valve to vent all pressure in the system after a fight. 7 is the fancy new valve we got from SMC that directs the regulated gas to 8, our cylinder. Upon careful examination you may notice that there are less parts in this diagram than in the last one, and there's a good reason for that. The new regulator has a much MUCH higher flow rate allowing for us to get rid of the buffer tank and all of its hardware. There also appears to be no pressure releif valve. Well it just so happens that the regulator has a BUILT IN pressure releif that is ever so nice. The whole low-pressure system has been upgraded to 1/2 inch tubing from 3/8 and is much faster and more powerful. It freakin rules! Strange Brew is now in the chosen few robots that are capable of performing one full flip on a self-right.