We are planning on using pneumatics for a Skyrise claw but we don’t have much experience using them. We have the programming down and the basic setup but we are wondering the best way to optimize it. For example, where’s the best placement for the open/close valve or the pressure valve? How do you know you have the optimized pressure and does decreasing pressure save air? What’s the easiest way to fill up the reservoir? Tips and tricks like these would help out a lot.
Also, can someone help explain the “L” fitting for the cylinder? We’ve turned the inside of it pretty much all the way open but less air is coming through it than the straight brass fitting.
Any thing you guys know about pneumatics would be very helpful! Thanks!
To save air it’s best to have the solenoid(the on off switch powered by the cortex) close to the pistons and farther away from the air tanks so you might want to mount them on the top of your lift.
Using the pressure regulator component definitely saves air for sure, just at the sacrifice of piston force. An analogy for the pressure regulator is like gear ratios. You can sacrifice speed for torque or vice versa, and with the pressure regulator you can sacrifice force for increased actuations. As you may know picking up skyrise sections does not need a lot of piston pressure, so what the regulator is doing is increasing efficiency by giving you enough pressure to pick up the section yet also give you the maximum amount actuations you can get out of your reservoirs. To use the regulator turning the knob clockwise increases pressure and counterclockwise reduces pressure. Additionally the air in port is the brass knob, and blue is out.
Filling reservoirs with a bike pump is the most common way of doing it and its really just manual labour nothing else really. You could bring an air compressor if you wanted and i’ve even seen some people with a special pump attached to a drill so that the electric drill does the compressing, but a bike pump will do fine for just 2 reservoirs.
The L fittings for the pistons are able to have the same airflow as the brass fittings. You are supposed to use a screwdriver and turn the “screw” inside counterclockwise to increase air flow so that it rotates and moves all the way to the top of the fitting.
There’s probably more stuff I forgot to mention so anyone else to add on?
I will add to Stanley’s great points to the OP that since your team is in FRC country, i.e. Michigan, try to reach out to a local veteran FRC if you do want to go the compressor route. Many FRC teams have older pneumatic components that they are not using that they will be more than happy to give to help out another local robotics team. Our team modified a compressor using a 550 Andymark Motor (the ones that make the little kide toys work) powered by a 12V FRC style battery. Our spare compressor is a personal one of mine from Harbor Freight that is pretty cost efficient but you might want to have a spare or two. http://www.harborfreight.com/12-volt-250-psi-compact-air-compressor-4077.html . What ever way you end up powering you system make sure you have an air gauge on your pump in order to see how much psi your system has, they fill up quick so be safe, and you are able to get you fitting off successfully without losing too much air. Also with only a two tank limit on robots for now and probably in the future, try to use the spring returned pistons as much as possible that way you are not using air on the return stroke.
I agree with the principal of using a sprung return where possible (such as the opening of a skyrise claw) however single acting pistons are not strictly necessary. A double acting piston can be sprung back with elastics and the option to go to a powered return is very useful for certain applications (and if I’m not mistaken double acting pistons are more compact). Double acting solenoids can have one outlet closed with a short (~2") length of tube folded over and zip-tied.
Also, I personally cannot see any real need for anything other than a decent bike pump to fill reservoirs, certainly with the current two tank limit for this season. Just my $0.02 worth.
One tip to add to those of Stanley, using the shut-off valve in-between your reservoirs and pump fitting is really useful for retaining full pressure when you take off your pump (you need the arrow on the fitting pointing towards the pump fitting I believe)