[dtengineering]

Although this robot has large cylinders, there are several steps that you can take to reduce air consumption.

First of all, a 2" diameter cylinder at 33psi consumes the same amount of air and produces the same amount of force as a 1.5" cylinder at 33psi... about 100lbs of force. If it turns out that you don't need that much force you can drop the pressure down to about 20-25 psi, so long as you use the correct valves. (I believe the SMC valves operate at a minimum pressure of 20psi, while the Festos require 30psi, but don't have the specs in front of me to confirm that.)

Secondly you can likely set at least the vertical piston up to be single-acting*, as the weight of your arm is likely more than enough to return it to the retracted position. In other words, rather than running a tube from the valve to the top side of the vertical cylinder, just plug the valve where the tubing comes out, and leave the top side of the cylinder open to atmosphere.... or just put one of the needle-valve flow restrictors on it and leave that open to atmosphere if you want to control how quickly it extends and retracts. This way you only use air to lift, and let gravity do the work when the cylinder retracts... a 50% savings in air consumption.

If you use bungee cords/surgical tubing on the arm cylinder, you can achieve a similar effect... use the tubing to retract the cylinder and you only need to use air to push it open.

So if you do find you are using too much air, just these simple steps could cut air consumption to about 1/6 of that when running the cylinders as double acting at 60psi.

Good luck,

Jason

* note that this is different from using a single-acting cylinder, which has a spring inside to power the return stroke. Single-acting cylinders are not an allowed component. Legal double-acting cylinders, however (such as you have) may be left open to atmosphere at one (or both, although that would be silly...) ends.

**EDIT: Just looked at the photos again and noticed that the weight of the arm will cause the vertical cylinder to extend... not retract. The concept works the same, but I had it upside down... connect pressure to the top of the cylinder, and leave the bottom port open to atmosphere. The weight of the arm will pull the cylinder open, then pressurize the top half of the cylinder to raise the arm.

P.S. Love the "jack stands" that the robot is sitting on, but hopefully all team members will remember to wear shoes that cover their toes to the competition.