We’re planning to have maybe three kicking distances using pnuematic pistons and a level kicker. We would like to vary the kick power using a adjustable pressure regulator.
The plan would be to set the master regulator to 60psi and the downstream regulator would be for adjustment for the kicker. Has anyone done this before? I was thinking to get another regulator and attach it to one of those window motors with an encoder to monitor the position of the knob. However this seems way to complicated. I would like to find a simpler way.
windell,
That is exactly how teams have adjusted downstream pressure in the past. It is not a great way to do it but it does work. You might want to investigate using multiple actuators that have different actions instead.
one option is to use a quick exhasut valve for fast release
calibrate the system to exhasut through the solenoid valve for a short kick, then have a second loop which can exhaust through a quck exhaust valve releasing air faster for a longer shot.
similar function could be achieved with flow controls on the exhaust side of the valves, have 2 loops set at different rates.
I was also thinking you could do this with 2 valves with differn’t sized orifices. If you did it right you would be able to get 3 differn’t air flows resulting in 3 kicking forces.
doing it this way would result in 2 differn’t air flows. If you open both valves at the same time you could get a third air flow. The differn’t air flows will result in differn’t kicking speeds.
What about having 3 solenoids all tee’d into the cylinder? Open one for short, 2 for medium, and 3 for fast. Or, have one or more be on a regulator set lower than 60 PSI and open that one (or more) for the short-range shots.
Where is the link to the “free” pneumatic cyliders? I followed the link " Where to get more " on related documents
2 Bimba Manufacturing Bimba Cylinders - custom order
clicked www.bimba.com
and it took me to
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Check out the IP610-60. I believe it should be relatively simple to integrate and very precise (especially compared to physically turning a pressure regulator!) if you have someone comfortable with programming and the control system.
I’ve not seen one of these in use before, but as far as I can tell in a quick rules check, they ARE legal pneumatic components AND legal electrical components for the 2010 FRC competition.
Note tha while a quick exhaust valve is a very useful pneumatic part, it’s use is not specifically permitted by <R72> and therefore PROHIBITED by <R71>
We are using a 2 in cyinder, it has a larger fittng hole so we installed a “T” and connected two valves. Two will allow for faster release and using just one will slow it down. You could add a thrid in line with the second with the pressure further reduced for close shots.
You’re thinking of the rules from some years ago. There hasn’t been a separate electronics limit for quite some time. $400 is the only limit other than the grand total.
Control system rules are not my area and I have not studied any changes for this year, but connecting outputs to a device such as an electronic regulator has always been prohibited in the past. We considered this exact same idea last year when looking for ways to vary our pneumatic catapult. The ruling was that the electronic regulator is an electromagnetic actuator just like a solenoid or prohibited servo or motor is, and therefore could not be used. Only kit motors, servos, and solenoid valves may recieve output signals, unless they have made a major change this year. I would study this carefully before proceeding.
Use one input solenoid and one exhaust solenoid, and adjust the kick by varying the on/off timing of the two in software. no pressure regulator necessary.
Al, it was a response ot the Q&A but with the way they worded the question they got a different rule outlawing it.
Quote from 2009 Q&A
Modified PWM Signal
Posted by FRC1986 at 01/19/2009 02:26:38 pm
Is it allowed to use a modified PWM signal to control an electronic pressure regulator to control
pneumatics?
A low pass filter would be used to convert the 5v digital PWM signal into a 0-5v analog signal.
Re: Modified PWM Signal
Posted by GDC at 01/22/2009 06:41:00 pm
No. That would be a violation of Rule <R67>.
Quote from 2009 Manual
<R67> All outputs from sensors, custom circuits and additional electronics shall connect to only the
following:
A. Other custom circuits, or
B. PWM Out, I2C, Relay or Digital I/O ports on the Digital Sidecar, or
C. Analog In ports on the Analog Breakout.
D. Ethernet Port 2 on the cRIO Mobile Device Controller (to which the Kit Of Parts-provided
camera, and only that camera, may be connected).