Pneumatic Axis of Control

[HaiThar]

I posted it on another thread as a theory, but now I am actually starting the project. Over the next few weeks, I will be building a pneumatic axis of control. I will eventually find a way to mount it on my spudgun, but for now, it's just a little project I have going on... As it is, I'm only 13, and therefore still living on allowance... -_- , so the stuff make take a bit to get... Anyway, I will update this post with pictures, information, and item's I have received...

Anyway, I've got the winning bid atm on two cylinders with 8" stroke...
I've decided to MODIFY my plans , so that instead of using the complicated horizontal that I had, I plan to make it fully rotational 360 degrees. If anyone has experience, in the motors though, I need to figure out how I can extend it...

I will update as I go along. I originally planned to have it controlled by a microcontroller, but that got confusing and complicated due to my limited technical knowledge, I will do that once I get it all set up...

Ebay, MCMaster, and All Electronics are going to be my primary sources of getting my goods... .

Also, if you would like to sell me any of this stuff, at a competitive price(heh), pm me and we'll see if we can work something out....

Thanks again to all the people who helped me work on and design this project....


Now, to how it's all going to work....

The vertical movement is probably the most simple. I fill the cylinders up with air simultaneously, and they both rise. Open the sprinkler valve that both are connected to, and they come down.

The tricky part was figuring out how to make a horizontal axis. You can get a pneumatic slide at MCMaster for $190, so I decided that I would make a homemade magnetic piston. Basically, there is a piston with a magnet in the middle of it, in the middle of a closed chamber. You fill the left side with air, the magnetic piston moves to the right, and the magnetic slide on the top follows it. I release air from the left and add air to the right side and the piston moves to the left side of the chamber, taking the slide with it. I can probably make a diagram if people are still having trouble... :-\

Anyway, the slide system will be mounted to the top of the pneumatic cylinders.

Anyway, I wanted this all to be controlled by a single system. I am using the two three way valves to direct which way I want the air to go. The first three way valve is connected directly to the tank. When it is opened, it leads to the left or the right. If it goes to the left, it will fill up the pneumatic cylinders and the structure will rise. If it goes to the right, it leads to another three way valve. It will then either be directed to the left or right side of the magnetic piston.

Anyway, I want to thank everyone who posted on my original thread, especially markfh11q and Gepard...

Pics of my things that I'm ordering will be posted as well as the status.

[ShowNoMercy]

Just another site to add to your list, try surpluscenter.com. They have a lot of good stuff and really cheap prices. And for your rotational movement why not use an arm and an air ram?

[HaiThar]

Rotational? I didn't think of that...what is an arm? Air rams are the same as pneumatic cylinders and a bit more expensive...

[ShowNoMercy]

Well rotational = horizontal movement I thought but if not disregard. And I just ordered an air ram for 9 bucks at surplus center with a solenoid to control it for another 9 bucks. A momentary switch for a buck and some relays for real cheap. But like have your vertical shaft able to spin and have an arm attached to it so an arm ram can in turn push or pull the arm which will consequently spin your whole pedestal.

[HaiThar]

Hmm....So maybe a pneumatic engine? : - \

Also, what do you mean it was controlled by a solenoid?

[MaxuS]

I dont understand why you're not going with DC Motors, they will be far less hassle, and if you can find a good seller, they will be cheaper too, and not to mention the fact that they can be readily plugged into a micro-controller..

By the way, just out of interest, what kind of cannon are fixing onto this?
It should be a semi-auto pneumatic if anything, walking to and fro after every shot can get tedious.

[HaiThar]

I dont understand why you're not going with DC Motors, they will be far less hassle, and if you can find a good seller, they will be cheaper too, and not to mention the fact that they can be readily plugged into a micro-controller..

By the way, just out of interest, what kind of cannon are fixing onto this?
It should be a semi-auto pneumatic if anything, walking to and fro after every shot can get tedious.

Looking at it now, A DC motor may be the way to go... If I do that, what I'll plan on doing is having 2 pneumatic cylinders + the motor. One cylinder will control tilt, the other will control height...

I haven't really worked with motors...How would I extend the shaft of the motor to be longer?

Won the auction...

As for the cannon, I hope to make it so there is a tank shared by the cannon AND the pneumatic lift. The cannon will be mounted in a sawed-off coupler of whatever the barrel size is. The coupler will be screwed onto the DC motor shaft, so when the motor turns, the barrel turns. The motor will be mounted on top of a plate that is mounted on top of the cylinder's shaft. I've got an extra cylinder, so maybe instead of the coupling I can do a clevis and control the tilt/slope?

[HaiThar]

$20 including shipping for my 8" stroke cylinders. Compared to like $25 + shipping on MC-Master. Anyway, I'm still looking for a motor, and I need to set up my air AND my electronics system. =(

Also, does anyone know of a good kidn of motor to get for what I'm going to be using?

I'd prefer $10 - $15 if possible..

[ShowNoMercy]

Something like this http://surpluscenter.com/item.asp?UID=2 ... e=electric or do you want a shaft like a linear actuator?

Like this http://surpluscenter.com/item.asp?UID=2 ... e=electric

[HaiThar]

Actually, I was changing it to like a pivot...Basically, just a motor with a longer shaft. It goes straight up into the base of the coupling and turns it directly.

[ShowNoMercy]

Like this? http://surpluscenter.com/item.asp?UID=2 ... e=electric

[HaiThar]

Yeah, that looks fine, but how does it directly connect up to the barrel? And it says 15 RPM. Is that strong enough to pull around a 1/2 - 1 pound?

[ShowNoMercy]

15 RPM would entail a lot of torque.

[mark.f]

If you integrate a DC motor for the horizontal movement, I believe I have an idea on how you can connect it to the cannon.

A turntable bearing, (which you've seen before on things like those huge lazy suzan tables or some rotating display cases), can be used to rotate the platform upon which the cannon and it's vertical control hardware is mounted. If you have a reasonably powerful motor at a high RPM, a small gearbox could be used to reduce the RPM to a much slower rate and increase the torque. You could then use either one or more rubber wheels to turn the bearing and the platform, (you might have to install a circular ledge on the bottom of the platform. I haven't taken a look at specific bearings yet). You may also have to install either a small pneumatic cylinder, (which I actually will admit would be a little overkill), or small DC solenoid for "braking" once you cut current from the motor. Since the platform will have a lot of rotational inertia, (depending on how much your cannon weighs), you may have to resort to more than one "brake".

Just some food for thought. I'm not a great electrician, but a simple circuit like a DC motor that's reversible is not beyond my rudimentary knowledge. Keep us posted on how you're coming along.

[Marco321]

When i was young, i built a robotic arm. It had up down and rotation, so it moved and aimed any where i wanted. It simply used a gear box and attached to DC motor for each set of directions. It was very simple yet effective. I could easily of attached a cannon to it instead of a claw, but unfortunately i pulled it apart..... but i still have the pieces.


EDIT: Except thats not using pneumatics..... Its a slightly easier method in my opinion because i don't have access to a constant source of air or the money and equipment to make it.