Voltage Controlled Valve - Help!
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Posts: 46,084
I am trying to make a miniture airvalve (for use with a 2 inch pneumatic
cylinder) that can be open and closed incrementally allowing for better
control of the air flow. How should I do this? I dont want to use a servo.
I would like to make the valve so it uses just a voltage. So the end goal
would be something where when you give the valve 1 volt it opens 1/4 of
the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
solution with electromagnets??? Anyway, any advise or guidance would be
much appreciated and I know someone out there has done something like
this already. Thanks
- Matt
cylinder) that can be open and closed incrementally allowing for better
control of the air flow. How should I do this? I dont want to use a servo.
I would like to make the valve so it uses just a voltage. So the end goal
would be something where when you give the valve 1 volt it opens 1/4 of
the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
solution with electromagnets??? Anyway, any advise or guidance would be
much appreciated and I know someone out there has done something like
this already. Thanks
- Matt
Comments
opens the valve a little more on each stroke. Or, use multiple valves with
different orifices, or a rotary valve.
Original Message
> I am trying to make a miniture airvalve (for use with a 2 inch pneumatic
> cylinder) that can be open and closed incrementally allowing for better
> control of the air flow. How should I do this? I dont want to use a servo.
> I would like to make the valve so it uses just a voltage. So the end goal
> would be something where when you give the valve 1 volt it opens 1/4 of
> the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
> solution with electromagnets??? Anyway, any advise or guidance would be
> much appreciated and I know someone out there has done something like
> this already. Thanks
fuel equipment that would net you three different flow rates from two
valves. Don't know how this would work for air.
Original Message
> Solenoid with a ratchet assembly attached to a ball valve. The solenoid
> opens the valve a little more on each stroke. Or, use multiple valves with
> different orifices, or a rotary valve.
>
>
Original Message
>
> > I am trying to make a miniture airvalve (for use with a 2 inch pneumatic
> > cylinder) that can be open and closed incrementally allowing for better
> > control of the air flow. How should I do this? I dont want to use a
servo.
> > I would like to make the valve so it uses just a voltage. So the end
goal
> > would be something where when you give the valve 1 volt it opens 1/4 of
> > the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
> > solution with electromagnets??? Anyway, any advise or guidance would be
> > much appreciated and I know someone out there has done something like
> > this already. Thanks
Check out a company called "proportional air" www.proportionair.com
will get back to you later with more companies.
David Fixemer
a servo or something). I have played with a solenoid but it is either on
or off, extended or not. What solenoid works on an voltage increment and
moves with enough accuracy?
- Matt
On Thu, 1 Mar 2001, Rodent wrote:
> Solenoid with a ratchet assembly attached to a ball valve. The solenoid
> opens the valve a little more on each stroke. Or, use multiple valves with
> different orifices, or a rotary valve.
>
>
Original Message
>
> > I am trying to make a miniture airvalve (for use with a 2 inch pneumatic
> > cylinder) that can be open and closed incrementally allowing for better
> > control of the air flow. How should I do this? I dont want to use a servo.
> > I would like to make the valve so it uses just a voltage. So the end goal
> > would be something where when you give the valve 1 volt it opens 1/4 of
> > the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
> > solution with electromagnets??? Anyway, any advise or guidance would be
> > much appreciated and I know someone out there has done something like
> > this already. Thanks
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
go under the "whats new"
read the third paragraph down "In addition . . . "
also look at the picture at the bottom of the page.
David Fixemer
click at a time. Same theory here.
The solenoid stroke and ratchet arm determines the movement. suppose you had
a ratchet with 20 teeth, and each stroke of the solenoid moved it one tooth.
using a ball valve that will turn 360 degrees, the first 5 strokes takes the
valve from closed to full open, the next 5 from full open to closed. All you
do is keep track of the strokes.
Original Message
> Wouldnt you still need to have something driving the rachet assembly (like
> a servo or something). I have played with a solenoid but it is either on
> or off, extended or not. What solenoid works on an voltage increment and
> moves with enough accuracy?
> > Solenoid with a ratchet assembly attached to a ball valve. The solenoid
> > opens the valve a little more on each stroke. Or, use multiple valves
with
> > different orifices, or a rotary valve.
> >
> >
Original Message
> >
> > > I am trying to make a miniture airvalve (for use with a 2 inch
pneumatic
> > > cylinder) that can be open and closed incrementally allowing for
better
> > > control of the air flow. How should I do this? I dont want to use a
servo.
> > > I would like to make the valve so it uses just a voltage. So the end
goal
> > > would be something where when you give the valve 1 volt it opens 1/4
of
> > > the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
> > > solution with electromagnets??? Anyway, any advise or guidance would
be
> > > much appreciated and I know someone out there has done something like
> > > this already. Thanks
cylinder) that can be open and closed incrementally allowing for better
control of the air flow. How should I do this? I dont want to use aservo.
I would like to make the valve so it uses just a voltage. So the endgoal
would be something where when you give the valve 1 volt it opens 1/4of
the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
solution with electromagnets??? Anyway, any advise or guidance wouldbe
much appreciated and I know someone out there has done something like
this already. Thanks
- Matt
·
Matt,
Finally something on the list I can say something about!
IF your final goal to control the speed at which the pneumatic cylinderextends and returns,· using a ball valve is going to be considerablymore difficult and less precise.
A very common way to "speed control" pneumatic cylinders is to use pulsesapplied to an electromagnetic valve.· 5VDC valves are very common,fast, and pretty affordable starting in the neighborhood of about $15.00if you buy surplus, $25.00 if you buy new.
You can achieve the effect you want. Rather than using proportionalvoltages, you use proportional pulses.· Both the width· and speedof the pulse can be varied to achieve various speeds.·· Anothergood thing is that these valves are pretty easily interfaced to the stamp.·To protect mine (stamp) I used solid state relays from digikey, then aseparate 5v power supply to drive the relays.· I have also seen plansusing transistors rather than relays, but, when I was building the initialproject, my skill level was somewhat low, so I opted for the easiest way(for me).
Even using the solid state relays, I've been told to be sure to usea clamping diode to protect my stamp.
I am QUITE sure that there are many people on the list that can providefurther information and various methods od "pulsing" the valves.
If you have any questions on the valves, I can probably help, the electronics....wellthe list can probably do better for you..
Hope this helps!
Rus
--
Rus Hardy
"Lucky Devil"
Atrophies - Ghoulishly Original Awards & Trophies
http://www.bluedestiny.com/Atrophies/
SpiderBucky & SpiderThrifty - Boney Superheroes
http://www.bluedestiny.com/SpiderBucky/
Keeper of the Bucky-n-Thrifty Flame
http://www.boneyardbargains.com/
"my mind wanders....I'm just along for the ride"
for the Electromagnetic valve you used?
Also, I would like to from others on the list if there is a way in fact to
create the pulses that are needed without using a Stamp to do it? I am
trying to accomplish this valve part of the project without using any
overhead from the stamp itself. But just in case I do need to, is
controlling this electronic valve done just like controlling a servo using
PULSEOUT?
- Matt
On Thu, 1 Mar 2001, Rus Hardy wrote:
> Matt Johnson wrote:
>
> > I am trying to make a miniture airvalve (for use with a 2 inch pneumatic
> > cylinder) that can be open and closed incrementally allowing for better
> > control of the air flow. How should I do this? I dont want to use a servo.
> > I would like to make the valve so it uses just a voltage. So the end goal
> > would be something where when you give the valve 1 volt it opens 1/4 of
> > the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
> > solution with electromagnets??? Anyway, any advise or guidance would be
> > much appreciated and I know someone out there has done something like
> > this already. Thanks
> >
> > - Matt
> >
>
> Matt,
>
> Finally something on the list I can say something about!
>
> IF your final goal to control the speed at which the pneumatic cylinder
> extends and returns, using a ball valve is going to be considerably more
> difficult and less precise.
>
> A very common way to "speed control" pneumatic cylinders is to use pulses
> applied to an electromagnetic valve. 5VDC valves are very common, fast, and
> pretty affordable starting in the neighborhood of about $15.00 if you buy
> surplus, $25.00 if you buy new.
>
> You can achieve the effect you want. Rather than using proportional voltages,
> you use proportional pulses. Both the width and speed of the pulse can be
> varied to achieve various speeds. Another good thing is that these valves
> are pretty easily interfaced to the stamp. To protect mine (stamp) I used
> solid state relays from digikey, then a separate 5v power supply to drive the
> relays. I have also seen plans using transistors rather than relays, but,
> when I was building the initial project, my skill level was somewhat low, so I
> opted for the easiest way (for me).
>
> Even using the solid state relays, I've been told to be sure to use a clamping
> diode to protect my stamp.
>
> I am QUITE sure that there are many people on the list that can provide
> further information and various methods od "pulsing" the valves.
>
> If you have any questions on the valves, I can probably help, the
> electronics....well the list can probably do better for you..
>
> Hope this helps!
>
> Rus
>
> --
> Rus Hardy
> "Lucky Devil"
> Atrophies - Ghoulishly Original Awards & Trophies
> http://www.bluedestiny.com/Atrophies/
> SpiderBucky & SpiderThrifty - Boney Superheroes
> http://www.bluedestiny.com/SpiderBucky/
> Keeper of the Bucky-n-Thrifty Flame
> http://www.boneyardbargains.com/
> "my mind wanders....I'm just along for the ride"
>
>
I'll try to dig it out tonight and post it to the list tomorrow.
Rus
Matt Johnson wrote:
for the Electromagnetic valve you used?
Also, I would like to from others on the list if there is a way in factto
create the pulses that are needed without using a Stamp to do it? Iam
trying to accomplish this valve part of the project without using any
overhead from the stamp itself. But just in case I do need to, is
controlling this electronic valve done just like controlling a servousing
PULSEOUT?
- Matt
On Thu, 1 Mar 2001, Rus Hardy wrote:
> Matt Johnson wrote:
>
> > I am trying to make a miniture airvalve (for use with a 2 inchpneumatic
> > cylinder) that can be open and closed incrementally allowing forbetter
> > control of the air flow. How should I do this? I dont want to usea servo.
> > I would like to make the valve so it uses just a voltage. So theend goal
> > would be something where when you give the valve 1 volt it opens1/4 of
> > the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
> > solution with electromagnets??? Anyway, any advise or guidancewould be
> > much appreciated and I know someone out there has done somethinglike
> > this already. Thanks
> >
> > - Matt
> >
>
> Matt,
>
> Finally something on the list I can say something about!
>
> IF your final goal to control the speed at which the pneumatic cylinder
> extends and returns,· using a ball valve is going to be considerablymore
> difficult and less precise.
>
> A very common way to "speed control" pneumatic cylinders is to usepulses
> applied to an electromagnetic valve.· 5VDC valves are very common,fast, and
> pretty affordable starting in the neighborhood of about $15.00 ifyou buy
> surplus, $25.00 if you buy new.
>
> You can achieve the effect you want. Rather than using proportionalvoltages,
> you use proportional pulses.· Both the width· and speedof the pulse can be
> varied to achieve various speeds.·· Another good thingis that these valves
> are pretty easily interfaced to the stamp.· To protect mine(stamp) I used
> solid state relays from digikey, then a separate 5v power supplyto drive the
> relays.· I have also seen plans using transistors rather thanrelays, but,
> when I was building the initial project, my skill level was somewhatlow, so I
> opted for the easiest way (for me).
>
> Even using the solid state relays, I've been told to be sure to usea clamping
> diode to protect my stamp.
>
> I am QUITE sure that there are many people on the list that can provide
> further information and various methods od "pulsing" the valves.
>
> If you have any questions on the valves, I can probably help, the
> electronics....well the list can probably do better for you..
>
> Hope this helps!
>
> Rus
·
--
Rus Hardy
"Lucky Devil"
Atrophies - Ghoulishly Original Awards & Trophies
http://www.bluedestiny.com/Atrophies/
SpiderBucky & SpiderThrifty - Boney Superheroes
http://www.bluedestiny.com/SpiderBucky/
Keeper of the Bucky-n-Thrifty Flame
http://www.boneyardbargains.com/
"my mind wanders....I'm just along for the ride"
I'm still working on the project. To date have done nothing besides receive
literature and collect information. However, should you volunteer to be the
guniee pig, let me know how they work. I also agree with the person that
this is not a good way to regulate the "speed" of a cylinder. However, it
is a great way to regulate the pressure on a cylinder for example in the
welding of different sized parts. (I've seen other companies do this. This
will be my first time.)
David Fixemer
cylinder pressure, but what i was doing was making a closed loop feedback servo
kind of thing. instead of speed regulation, however, it was for position
feedback. it had a linear slide pot
attached to the cylinder, a pair of comparators, a voltage divider for input
position, a 555 to make the pulses, and an and gate to mix the pulses with the
comparator output. kind of complicated, and it can all be done with one pic
12c671 and a pair of pots.
what i learned was two things: use the fastest valve you can find, and the
fastest relays. the valves i had were slow, and didn't give much control. the
relays i was using were mechanical; optical would have doubled the speed of the
apparatus. as it was, it did a lot of
seeking (back and forth around the target position) and jerking from place to
place.
if you're interested in the analog approach, i can scan the schematic and send
it over, but it is of little use for more than hobby applications.
-raphael abrams
nyc
Does anyone use small pneumatics in robotics? like using pnematically
controlled joints instead of servos? how do they do it?
I have found nothing in the way of resources on the web about
pneumatically controlled robotic arms (accept for some lego contraption
that is too symplistic) I have found a good air valve that is controlled
by a servo (which is exactly what I dont want to do) for use on radio
controlled airplanes with pneumatic landing gear.
I would like the schematic though of the analog approach.
- Matt
On Thu, 1 Mar 2001, raphael wrote:
> for you pnuematic valve folks: i have also used the pulsing method of
regulating cylinder pressure, but what i was doing was making a closed loop
feedback servo kind of thing. instead of speed regulation, however, it was for
position feedback. it had a linear slide pot
> attached to the cylinder, a pair of comparators, a voltage divider for input
position, a 555 to make the pulses, and an and gate to mix the pulses with the
comparator output. kind of complicated, and it can all be done with one pic
12c671 and a pair of pots.
>
> what i learned was two things: use the fastest valve you can find, and the
fastest relays. the valves i had were slow, and didn't give much control. the
relays i was using were mechanical; optical would have doubled the speed of the
apparatus. as it was, it did a lot of
> seeking (back and forth around the target position) and jerking from place to
place.
>
> if you're interested in the analog approach, i can scan the schematic and send
it over, but it is of little use for more than hobby applications.
>
> -raphael abrams
> nyc
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
surgical tubing for proportional control of robotics equipment. Basically,
there was a tee fitting that fed two pieces of tubing. Both pieces of
tubing were folded back over themselves and the angle was controlled by a
standard R/C servo, one end of each horn controlled its own tubing valve.
The tee fed each piece and the other end of each was the output of the
valve. Amazingly simple. When you closed one valve you opened the other by
an opposite amount, so you could control the position of a pneumatic
cylinder by linearly driving opposing pressures on each side of the piston.
I used to have the web site bookmarked some time ago, but I don't have
it anymore. Ingenious design. To quote Jimmy Buffet: "It was so simple
like the jitterbug, it plum evaded me!"
Original Message
From: Matt Johnson <matt@p...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, March 01, 2001 8:18 AM
Subject: [noparse][[/noparse]basicstamps] Voltage Controlled Valve - Help!
>
> I am trying to make a miniture airvalve (for use with a 2 inch pneumatic
> cylinder) that can be open and closed incrementally allowing for better
> control of the air flow. How should I do this? I dont want to use a servo.
> I would like to make the valve so it uses just a voltage. So the end goal
> would be something where when you give the valve 1 volt it opens 1/4 of
> the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
> solution with electromagnets??? Anyway, any advise or guidance would be
> much appreciated and I know someone out there has done something like
> this already. Thanks
>
>
> - Matt
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
> cylinder extends and returns, using a ball valve is going to be
considerably
> more difficult and less precise.
> A very common way to "speed control" pneumatic cylinders is to use
> pulses applied to an electromagnetic valve. 5VDC valves are very
common,
> fast, and pretty affordable starting in the neighborhood of about
$15.00 if
> you buy surplus, $25.00 if you buy new.
What manufacturer of valves have you used? Mac, Parker, Numatics, Festo,
????
What kind of porting? 4 way, 3 way, NC, NO, ???
> You can achieve the effect you want. Rather than using proportional
> voltages, you use proportional pulses. Both the width and speed of
the pulse
> can be varied to achieve various speeds. Another good thing is that
these
> valves are pretty easily interfaced to the stamp. To protect mine
(stamp)
> I used solid state relays from digikey, then a separate 5v power supply
to
> drive the relays. I have also seen plans using transistors rather than
> relays, but, when I was building the initial project, my skill level
was somewhat
> low, so I opted for the easiest way (for me).
Can you explain some more? Doesn't pulsing the valve just shift the
spool each time, causing the cylinder to extend or retract. I thought
speed control was don't by adjusting the flow. I'm not sure I understand
how your method changes the flow... Am I way off in left field?
> >Matt,
> >
> >I'll try to dig it out tonight and post it to the list tomorrow.
> >
> >Rus
> >
> >Matt Johnson wrote:
> >
> >> Rus, that helps quite a bit, thank you. Do you have a Digikey part number
> >> for the Electromagnetic valve you used?
> >>
> >> Also, I would like to from others on the list if there is a way in fact to
> >> create the pulses that are needed without using a Stamp to do it? I am
> >> trying to accomplish this valve part of the project without using any
> >> overhead from the stamp itself. But just in case I do need to, is
> >> controlling this electronic valve done just like controlling a servo using
> >> PULSEOUT?
> >>
> >> - Matt
> >>
> >> On Thu, 1 Mar 2001, Rus Hardy wrote:
> >>
> >> > Matt Johnson wrote:
> >> >
> >> > > I am trying to make a miniture airvalve (for use with a 2 inch
pneumatic
> >> > > cylinder) that can be open and closed incrementally allowing for better
> >> > > control of the air flow. How should I do this? I dont want to use a
servo.
>
> >> > > I would like to make the valve so it uses just a voltage. So the end
goal
>
> >> > > would be something where when you give the valve 1 volt it opens 1/4 of
> >> > > the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
> >> > > solution with electromagnets??? Anyway, any advise or guidance would be
> >> > > much appreciated and I know someone out there has done something like
> >> > > this already. Thanks
> >> > >
> >> > > - Matt
> >> > >
> >> >
> >> > Matt,
> >> >
> >> > Finally something on the list I can say something about!
> >> >
> >> > IF your final goal to control the speed at which the pneumatic cylinder
> >> > extends and returns, using a ball valve is going to be considerably more
> >> > difficult and less precise.
> >> >
> >> > A very common way to "speed control" pneumatic cylinders is to use pulses
> >> > applied to an electromagnetic valve. 5VDC valves are very common, fast,
and
>
> >> > pretty affordable starting in the neighborhood of about $15.00 if you buy
> >> > surplus, $25.00 if you buy new.
> >> >
> >> > You can achieve the effect you want. Rather than using proportional
voltages,
>
> >> > you use proportional pulses. Both the width and speed of the pulse can
be
>
> >> > varied to achieve various speeds. Another good thing is that these
valves
>
> >> > are pretty easily interfaced to the stamp. To protect mine (stamp) I
used
> >> > solid state relays from digikey, then a separate 5v power supply to drive
the
>
> >> > relays. I have also seen plans using transistors rather than relays,
but,
> >> > when I was building the initial project, my skill level was somewhat low,
so
> I
> >> > opted for the easiest way (for me).
> >> >
> >> > Even using the solid state relays, I've been told to be sure to use a
clamping
>
> >> > diode to protect my stamp.
> >> >
> >> > I am QUITE sure that there are many people on the list that can provide
> >> > further information and various methods od "pulsing" the valves.
> >> >
> >> > If you have any questions on the valves, I can probably help, the
> >> > electronics....well the list can probably do better for you..
> >> >
> >> > Hope this helps!
> >> >
> >> > Rus
> >>
> >
> >rus
> I dont belive a air cycl. can be controlled to stop at a given point
with
> out elaborate air circits thats why hyd. is usually used to posistion a cyl.
and
> they usually use a hyd. proportional valve
> max
> >
Max,
I was unaware that this was a "positioning" issue. That is primarily
why I qualified
my comments by beginning with with "IF your final goal to control the
speed at which
the pneumatic cylinder extends and returns".
You are correct...If critical positioning is the desired final result
then the project
becomes a bit more difficult using air.
However, I was working from a speed rather than positioning issue.
That being said.....using a 5/3 (five port/three position) or 4/3 valve
with a double
acting cylinder would allow relatively precise positioning using pulse
modulation. You
will have a bit of "compression cushioning" due to air's ability to be
compressed.
This is the reason hydraulic fluid is used in a closed system when
positioning is
critical, as this fluid does not appreciably compress (near zero
compression) thus
eliminating the "cushion"effect.
This is done quite frequently.
Rus
--
Rus Hardy
"Lucky Devil"
Atrophies - Ghoulishly Original Awards & Trophies
http://www.bluedestiny.com/Atrophies/
SpiderBucky & SpiderThrifty - Boney Superheroes
http://www.bluedestiny.com/SpiderBucky/
Keeper of the Bucky-n-Thrifty Flame
http://www.boneyardbargains.com/
"my mind wanders....I'm just along for the ride"
common but if you are saying you cant do positioning accurately then maybe
not...
- Matt
On Fri, 2 Mar 2001, Rus Hardy wrote:
> Max Powell wrote:
>
> > >Matt,
> > >
> > >I'll try to dig it out tonight and post it to the list tomorrow.
> > >
> > >Rus
> > >
> > >Matt Johnson wrote:
> > >
> > >> Rus, that helps quite a bit, thank you. Do you have a Digikey part number
> > >> for the Electromagnetic valve you used?
> > >>
> > >> Also, I would like to from others on the list if there is a way in fact
to
> > >> create the pulses that are needed without using a Stamp to do it? I am
> > >> trying to accomplish this valve part of the project without using any
> > >> overhead from the stamp itself. But just in case I do need to, is
> > >> controlling this electronic valve done just like controlling a servo
using
> > >> PULSEOUT?
> > >>
> > >> - Matt
> > >>
> > >> On Thu, 1 Mar 2001, Rus Hardy wrote:
> > >>
> > >> > Matt Johnson wrote:
> > >> >
> > >> > > I am trying to make a miniture airvalve (for use with a 2 inch
pneumatic
> > >> > > cylinder) that can be open and closed incrementally allowing for
better
> > >> > > control of the air flow. How should I do this? I dont want to use a
servo.
> >
> > >> > > I would like to make the valve so it uses just a voltage. So the end
goal
> >
> > >> > > would be something where when you give the valve 1 volt it opens 1/4
of
> > >> > > the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
> > >> > > solution with electromagnets??? Anyway, any advise or guidance would
be
> > >> > > much appreciated and I know someone out there has done something like
> > >> > > this already. Thanks
> > >> > >
> > >> > > - Matt
> > >> > >
> > >> >
> > >> > Matt,
> > >> >
> > >> > Finally something on the list I can say something about!
> > >> >
> > >> > IF your final goal to control the speed at which the pneumatic cylinder
> > >> > extends and returns, using a ball valve is going to be considerably
more
> > >> > difficult and less precise.
> > >> >
> > >> > A very common way to "speed control" pneumatic cylinders is to use
pulses
> > >> > applied to an electromagnetic valve. 5VDC valves are very common,
fast, and
> >
> > >> > pretty affordable starting in the neighborhood of about $15.00 if you
buy
> > >> > surplus, $25.00 if you buy new.
> > >> >
> > >> > You can achieve the effect you want. Rather than using proportional
voltages,
> >
> > >> > you use proportional pulses. Both the width and speed of the pulse
can be
> >
> > >> > varied to achieve various speeds. Another good thing is that these
valves
> >
> > >> > are pretty easily interfaced to the stamp. To protect mine (stamp) I
used
> > >> > solid state relays from digikey, then a separate 5v power supply to
drive the
> >
> > >> > relays. I have also seen plans using transistors rather than relays,
but,
> > >> > when I was building the initial project, my skill level was somewhat
low, so
> > I
> > >> > opted for the easiest way (for me).
> > >> >
> > >> > Even using the solid state relays, I've been told to be sure to use a
clamping
> >
> > >> > diode to protect my stamp.
> > >> >
> > >> > I am QUITE sure that there are many people on the list that can provide
> > >> > further information and various methods od "pulsing" the valves.
> > >> >
> > >> > If you have any questions on the valves, I can probably help, the
> > >> > electronics....well the list can probably do better for you..
> > >> >
> > >> > Hope this helps!
> > >> >
> > >> > Rus
> > >>
> > >
> > >rus
> > I dont belive a air cycl. can be controlled to stop at a given point
with
> > out elaborate air circits thats why hyd. is usually used to posistion a cyl.
and
> > they usually use a hyd. proportional valve
> > max
> > >
>
> Max,
>
> I was unaware that this was a "positioning" issue. That is primarily
> why I qualified
> my comments by beginning with with "IF your final goal to control the
> speed at which
> the pneumatic cylinder extends and returns".
>
> You are correct...If critical positioning is the desired final result
> then the project
> becomes a bit more difficult using air.
>
> However, I was working from a speed rather than positioning issue.
>
> That being said.....using a 5/3 (five port/three position) or 4/3 valve
> with a double
> acting cylinder would allow relatively precise positioning using pulse
> modulation. You
> will have a bit of "compression cushioning" due to air's ability to be
> compressed.
> This is the reason hydraulic fluid is used in a closed system when
> positioning is
> critical, as this fluid does not appreciably compress (near zero
> compression) thus
> eliminating the "cushion"effect.
>
> This is done quite frequently.
>
> Rus
>
> --
> Rus Hardy
> "Lucky Devil"
> Atrophies - Ghoulishly Original Awards & Trophies
> http://www.bluedestiny.com/Atrophies/
> SpiderBucky & SpiderThrifty - Boney Superheroes
> http://www.bluedestiny.com/SpiderBucky/
> Keeper of the Bucky-n-Thrifty Flame
> http://www.boneyardbargains.com/
> "my mind wanders....I'm just along for the ride"
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
Air bladder, you can input any small increment of air, and it will increase
in size. You could place the bladder under your device, and have it push
against a control arm. With a cylinder, you have the problems of the piston
sticking in its bore, and overcoming friction of the O-ring around the
piston, friction of shaft seals around the piston rod, etc. This is not a
problem with hydraulic cylinders, only air cylinders.
You could use a minature air regulator, connected to some method of
adjusting the regulator. Maybe a Potentiometer that is controlled by an
electric motor, such as the remote control Stereo volume controls use. In
these the actual volume control dial will turn from remote control.
Good luck
At 09:07 AM 3/2/2001 -0800, you wrote:
>
>So do people not use Pneumatics for robotic applications? I thought it was
>common but if you are saying you cant do positioning accurately then maybe
>not...
>
>- Matt
>
>
>On Fri, 2 Mar 2001, Rus Hardy wrote:
>
>> Max Powell wrote:
>>
>> > >Matt,
>> > >
>> > >I'll try to dig it out tonight and post it to the list tomorrow.
>> > >
>> > >Rus
>> > >
>> > >Matt Johnson wrote:
>> > >
>> > >> Rus, that helps quite a bit, thank you. Do you have a Digikey part
number
>> > >> for the Electromagnetic valve you used?
>> > >>
>> > >> Also, I would like to from others on the list if there is a way in
fact to
>> > >> create the pulses that are needed without using a Stamp to do it? I am
>> > >> trying to accomplish this valve part of the project without using any
>> > >> overhead from the stamp itself. But just in case I do need to, is
>> > >> controlling this electronic valve done just like controlling a servo
using
>> > >> PULSEOUT?
>> > >>
>> > >> - Matt
>> > >>
>> > >> On Thu, 1 Mar 2001, Rus Hardy wrote:
>> > >>
>> > >> > Matt Johnson wrote:
>> > >> >
>> > >> > > I am trying to make a miniture airvalve (for use with a 2 inch
pneumatic
>> > >> > > cylinder) that can be open and closed incrementally allowing for
better
>> > >> > > control of the air flow. How should I do this? I dont want to
use a servo.
>> >
>> > >> > > I would like to make the valve so it uses just a voltage. So the
end goal
>> >
>> > >> > > would be something where when you give the valve 1 volt it opens
1/4 of
>> > >> > > the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
>> > >> > > solution with electromagnets??? Anyway, any advise or guidance
would be
>> > >> > > much appreciated and I know someone out there has done something
like
>> > >> > > this already. Thanks
>> > >> > >
>> > >> > > - Matt
>> > >> > >
>> > >> >
>> > >> > Matt,
>> > >> >
>> > >> > Finally something on the list I can say something about!
>> > >> >
>> > >> > IF your final goal to control the speed at which the pneumatic
cylinder
>> > >> > extends and returns, using a ball valve is going to be
considerably more
>> > >> > difficult and less precise.
>> > >> >
>> > >> > A very common way to "speed control" pneumatic cylinders is to use
pulses
>> > >> > applied to an electromagnetic valve. 5VDC valves are very common,
fast, and
>> >
>> > >> > pretty affordable starting in the neighborhood of about $15.00 if
you buy
>> > >> > surplus, $25.00 if you buy new.
>> > >> >
>> > >> > You can achieve the effect you want. Rather than using
proportional voltages,
>> >
>> > >> > you use proportional pulses. Both the width and speed of the
pulse can be
>> >
>> > >> > varied to achieve various speeds. Another good thing is that
these valves
>> >
>> > >> > are pretty easily interfaced to the stamp. To protect mine
(stamp) I used
>> > >> > solid state relays from digikey, then a separate 5v power supply
to drive the
>> >
>> > >> > relays. I have also seen plans using transistors rather than
relays, but,
>> > >> > when I was building the initial project, my skill level was
somewhat low, so
>> > I
>> > >> > opted for the easiest way (for me).
>> > >> >
>> > >> > Even using the solid state relays, I've been told to be sure to
use a clamping
>> >
>> > >> > diode to protect my stamp.
>> > >> >
>> > >> > I am QUITE sure that there are many people on the list that can
provide
>> > >> > further information and various methods od "pulsing" the valves.
>> > >> >
>> > >> > If you have any questions on the valves, I can probably help, the
>> > >> > electronics....well the list can probably do better for you..
>> > >> >
>> > >> > Hope this helps!
>> > >> >
>> > >> > Rus
>> > >>
>> > >
>> > >rus
>> > I dont belive a air cycl. can be controlled to stop at a given
point with
>> > out elaborate air circits thats why hyd. is usually used to posistion a
cyl. and
>> > they usually use a hyd. proportional valve
>> > max
>> > >
>>
>> Max,
>>
>> I was unaware that this was a "positioning" issue. That is primarily
>> why I qualified
>> my comments by beginning with with "IF your final goal to control the
>> speed at which
>> the pneumatic cylinder extends and returns".
>>
>> You are correct...If critical positioning is the desired final result
>> then the project
>> becomes a bit more difficult using air.
>>
>> However, I was working from a speed rather than positioning issue.
>>
>> That being said.....using a 5/3 (five port/three position) or 4/3 valve
>> with a double
>> acting cylinder would allow relatively precise positioning using pulse
>> modulation. You
>> will have a bit of "compression cushioning" due to air's ability to be
>> compressed.
>> This is the reason hydraulic fluid is used in a closed system when
>> positioning is
>> critical, as this fluid does not appreciably compress (near zero
>> compression) thus
>> eliminating the "cushion"effect.
>>
>> This is done quite frequently.
>>
>> Rus
>>
>> --
>> Rus Hardy
>> "Lucky Devil"
>> Atrophies - Ghoulishly Original Awards & Trophies
>> http://www.bluedestiny.com/Atrophies/
>> SpiderBucky & SpiderThrifty - Boney Superheroes
>> http://www.bluedestiny.com/SpiderBucky/
>> Keeper of the Bucky-n-Thrifty Flame
>> http://www.boneyardbargains.com/
>> "my mind wanders....I'm just along for the ride"
>>
>>
>>
>> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>>
>>
>>
>
>
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
Sincerely
Kerry
Admin@M...
WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
Kerry Barlow
p.o. box 21
kirkwood ny
13795
- Matt
On Fri, 2 Mar 2001, Kerry Barlow wrote:
> Have you tried using a bladder instead of a cylinder as your valve? Using an
> Air bladder, you can input any small increment of air, and it will increase
> in size. You could place the bladder under your device, and have it push
> against a control arm. With a cylinder, you have the problems of the piston
> sticking in its bore, and overcoming friction of the O-ring around the
> piston, friction of shaft seals around the piston rod, etc. This is not a
> problem with hydraulic cylinders, only air cylinders.
> You could use a minature air regulator, connected to some method of
> adjusting the regulator. Maybe a Potentiometer that is controlled by an
> electric motor, such as the remote control Stereo volume controls use. In
> these the actual volume control dial will turn from remote control.
> Good luck
>
>
>
>
>
> At 09:07 AM 3/2/2001 -0800, you wrote:
> >
> >So do people not use Pneumatics for robotic applications? I thought it was
> >common but if you are saying you cant do positioning accurately then maybe
> >not...
> >
> >- Matt
> >
> >
> >On Fri, 2 Mar 2001, Rus Hardy wrote:
> >
> >> Max Powell wrote:
> >>
> >> > >Matt,
> >> > >
> >> > >I'll try to dig it out tonight and post it to the list tomorrow.
> >> > >
> >> > >Rus
> >> > >
> >> > >Matt Johnson wrote:
> >> > >
> >> > >> Rus, that helps quite a bit, thank you. Do you have a Digikey part
> number
> >> > >> for the Electromagnetic valve you used?
> >> > >>
> >> > >> Also, I would like to from others on the list if there is a way in
> fact to
> >> > >> create the pulses that are needed without using a Stamp to do it? I am
> >> > >> trying to accomplish this valve part of the project without using any
> >> > >> overhead from the stamp itself. But just in case I do need to, is
> >> > >> controlling this electronic valve done just like controlling a servo
> using
> >> > >> PULSEOUT?
> >> > >>
> >> > >> - Matt
> >> > >>
> >> > >> On Thu, 1 Mar 2001, Rus Hardy wrote:
> >> > >>
> >> > >> > Matt Johnson wrote:
> >> > >> >
> >> > >> > > I am trying to make a miniture airvalve (for use with a 2 inch
> pneumatic
> >> > >> > > cylinder) that can be open and closed incrementally allowing for
> better
> >> > >> > > control of the air flow. How should I do this? I dont want to
> use a servo.
> >> >
> >> > >> > > I would like to make the valve so it uses just a voltage. So the
> end goal
> >> >
> >> > >> > > would be something where when you give the valve 1 volt it opens
> 1/4 of
> >> > >> > > the way, 3 volts 1/2 way, 4 volts 3/4, etc... I thought maybe some
> >> > >> > > solution with electromagnets??? Anyway, any advise or guidance
> would be
> >> > >> > > much appreciated and I know someone out there has done something
> like
> >> > >> > > this already. Thanks
> >> > >> > >
> >> > >> > > - Matt
> >> > >> > >
> >> > >> >
> >> > >> > Matt,
> >> > >> >
> >> > >> > Finally something on the list I can say something about!
> >> > >> >
> >> > >> > IF your final goal to control the speed at which the pneumatic
> cylinder
> >> > >> > extends and returns, using a ball valve is going to be
> considerably more
> >> > >> > difficult and less precise.
> >> > >> >
> >> > >> > A very common way to "speed control" pneumatic cylinders is to use
> pulses
> >> > >> > applied to an electromagnetic valve. 5VDC valves are very common,
> fast, and
> >> >
> >> > >> > pretty affordable starting in the neighborhood of about $15.00 if
> you buy
> >> > >> > surplus, $25.00 if you buy new.
> >> > >> >
> >> > >> > You can achieve the effect you want. Rather than using
> proportional voltages,
> >> >
> >> > >> > you use proportional pulses. Both the width and speed of the
> pulse can be
> >> >
> >> > >> > varied to achieve various speeds. Another good thing is that
> these valves
> >> >
> >> > >> > are pretty easily interfaced to the stamp. To protect mine
> (stamp) I used
> >> > >> > solid state relays from digikey, then a separate 5v power supply
> to drive the
> >> >
> >> > >> > relays. I have also seen plans using transistors rather than
> relays, but,
> >> > >> > when I was building the initial project, my skill level was
> somewhat low, so
> >> > I
> >> > >> > opted for the easiest way (for me).
> >> > >> >
> >> > >> > Even using the solid state relays, I've been told to be sure to
> use a clamping
> >> >
> >> > >> > diode to protect my stamp.
> >> > >> >
> >> > >> > I am QUITE sure that there are many people on the list that can
> provide
> >> > >> > further information and various methods od "pulsing" the valves.
> >> > >> >
> >> > >> > If you have any questions on the valves, I can probably help, the
> >> > >> > electronics....well the list can probably do better for you..
> >> > >> >
> >> > >> > Hope this helps!
> >> > >> >
> >> > >> > Rus
> >> > >>
> >> > >
> >> > >rus
> >> > I dont belive a air cycl. can be controlled to stop at a given
> point with
> >> > out elaborate air circits thats why hyd. is usually used to posistion a
> cyl. and
> >> > they usually use a hyd. proportional valve
> >> > max
> >> > >
> >>
> >> Max,
> >>
> >> I was unaware that this was a "positioning" issue. That is primarily
> >> why I qualified
> >> my comments by beginning with with "IF your final goal to control the
> >> speed at which
> >> the pneumatic cylinder extends and returns".
> >>
> >> You are correct...If critical positioning is the desired final result
> >> then the project
> >> becomes a bit more difficult using air.
> >>
> >> However, I was working from a speed rather than positioning issue.
> >>
> >> That being said.....using a 5/3 (five port/three position) or 4/3 valve
> >> with a double
> >> acting cylinder would allow relatively precise positioning using pulse
> >> modulation. You
> >> will have a bit of "compression cushioning" due to air's ability to be
> >> compressed.
> >> This is the reason hydraulic fluid is used in a closed system when
> >> positioning is
> >> critical, as this fluid does not appreciably compress (near zero
> >> compression) thus
> >> eliminating the "cushion"effect.
> >>
> >> This is done quite frequently.
> >>
> >> Rus
> >>
> >> --
> >> Rus Hardy
> >> "Lucky Devil"
> >> Atrophies - Ghoulishly Original Awards & Trophies
> >> http://www.bluedestiny.com/Atrophies/
> >> SpiderBucky & SpiderThrifty - Boney Superheroes
> >> http://www.bluedestiny.com/SpiderBucky/
> >> Keeper of the Bucky-n-Thrifty Flame
> >> http://www.boneyardbargains.com/
> >> "my mind wanders....I'm just along for the ride"
> >>
> >>
> >>
> >> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> >>
> >>
> >>
> >
> >
> >
> >
> >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> >
> >
> >
> Sincerely
> Kerry
> Admin@M...
> WWW server hosting [url=Http://mntnweb.com]Http://mntnweb.com[/url]
> Kerry Barlow
> p.o. box 21
> kirkwood ny
> 13795
>
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
www.walrus.com/~raphael
good luck,
raphael
Actually, you can control position on pneumatic cylinders pretty accurately
and at much higher speeds than most people think. Unfortunately, the
controls for this are quite expensive. An example of this is an edge guide
for paper printing or slitting where large rolls of material with a non
uniform edge must be moved through the machine at high speed. Often, these
machines have to shift the roll (weighing hundreds of pounds) back and
forth within hundreds of milliseconds as the material web unwinds.
Pneumatic tracking is just one way that this is accomplished, but it
demonstrates how powerful and accurate pneumatic control can be. I have
worked with a system that uses a pneumatic "servo" and have often wondered
how this could be modified if I were using a Stamp to control the cylinder.
I'll see if I can find the site for the company.
Mike
At 09:07 AM 3/2/2001 -0800, you wrote:
>So do people not use Pneumatics for robotic applications? I thought it was
>common but if you are saying you cant do positioning accurately then maybe
>not...
>
>- Matt
have the stamp knowledge, just not the pneumatics. By the way, what are
good robotics resources on the web?
- Matt
On Fri, 2 Mar 2001, MIKE WALSH wrote:
> Matt,
> Actually, you can control position on pneumatic cylinders pretty accurately
> and at much higher speeds than most people think. Unfortunately, the
> controls for this are quite expensive. An example of this is an edge guide
> for paper printing or slitting where large rolls of material with a non
> uniform edge must be moved through the machine at high speed. Often, these
> machines have to shift the roll (weighing hundreds of pounds) back and
> forth within hundreds of milliseconds as the material web unwinds.
> Pneumatic tracking is just one way that this is accomplished, but it
> demonstrates how powerful and accurate pneumatic control can be. I have
> worked with a system that uses a pneumatic "servo" and have often wondered
> how this could be modified if I were using a Stamp to control the cylinder.
> I'll see if I can find the site for the company.
> Mike
>
>
> At 09:07 AM 3/2/2001 -0800, you wrote:
>
> >So do people not use Pneumatics for robotic applications? I thought it was
> >common but if you are saying you cant do positioning accurately then maybe
> >not...
> >
> >- Matt
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
Thanks in advance.
Daniel McGlothin
<snip>
if you're interested in the analog approach, i can scan the schematic and
send it over, but it is of little use for more than hobby applications.
</snip>
I'll defer to the robot experts on this one. It's an interesting subject to
follow, but I don't have the time or the resources to add robotics to my
list of "to-do's". Looks like there is a lot of interest in robotics with
this group, though, and I'd guess that you will get plenty of help if you ask.
Mike
> > At 09:07 AM 3/2/2001 -0800, you wrote:
> >
> > >So do people not use Pneumatics for robotic applications? I thought it was
> > >common but if you are saying you cant do positioning accurately then maybe
> > >not...
> > >
> > >- Matt
> >
enough 'power' in a 20 pound tank for more than a little work.
For stationry equipment, the cost/power ratio is all in favor the
pneumatics. A 20 psi air cylendar, no feedback, capable of liftng
200 pounds cost about $70.00. Lift time less than one second per
foot. Try that with a servo or stepper.
But don't try to postion an arm within 0.001" with a pnuematic
actuator. The feedback and valving will be much more than the
electronics, and the actuator will allow compression of the gas
therby making the holding power useless for precision work.
Pnuematic industrial actutors, 72" long, for postiioning, not
holding, will move 72" in a second, to within 0.001", but cost
upwards of $1,000.00 before you buy valves.
You CAN get pnuematics to do precision, but at costs more than
electroncs. Milling machines and lathes use steppers and ball
screws. Much better control. The Heating/ventaling world uses
pnuematics, much better bang for the buck when precison in not
important.
Hope this helps.
Dave
--- In basicstamps@y..., MIKE WALSH <walsh@c...> wrote:
> Matt,
> I'll defer to the robot experts on this one. It's an interesting
subject to
> follow, but I don't have the time or the resources to add robotics
to my
> list of "to-do's". Looks like there is a lot of interest in
robotics with
> this group, though, and I'd guess that you will get plenty of help
if you ask.
> Mike
>
> > > At 09:07 AM 3/2/2001 -0800, you wrote:
> > >
> > > >So do people not use Pneumatics for robotic applications? I
thought it was
> > > >common but if you are saying you cant do positioning
accurately then maybe
> > > >not...
> > > >
> > > >- Matt
> > >
pneumatics used in small time robotics (bore less then 3/4" stroke of 3")
And is the feedback basically just a POT? $70 seems cheap for a prototype.
Where do you get the stuff?
- Matt
On Mon, 5 Mar 2001 davemucha@j... wrote:
> For automonus robots, it's the air supply. there is just not
> enough 'power' in a 20 pound tank for more than a little work.
>
> For stationry equipment, the cost/power ratio is all in favor the
> pneumatics. A 20 psi air cylendar, no feedback, capable of liftng
> 200 pounds cost about $70.00. Lift time less than one second per
> foot. Try that with a servo or stepper.
>
> But don't try to postion an arm within 0.001" with a pnuematic
> actuator. The feedback and valving will be much more than the
> electronics, and the actuator will allow compression of the gas
> therby making the holding power useless for precision work.
>
> Pnuematic industrial actutors, 72" long, for postiioning, not
> holding, will move 72" in a second, to within 0.001", but cost
> upwards of $1,000.00 before you buy valves.
>
> You CAN get pnuematics to do precision, but at costs more than
> electroncs. Milling machines and lathes use steppers and ball
> screws. Much better control. The Heating/ventaling world uses
> pnuematics, much better bang for the buck when precison in not
> important.
>
> Hope this helps.
>
> Dave
>
>
>
>
>
>
>
> --- In basicstamps@y..., MIKE WALSH <walsh@c...> wrote:
> > Matt,
> > I'll defer to the robot experts on this one. It's an interesting
> subject to
> > follow, but I don't have the time or the resources to add robotics
> to my
> > list of "to-do's". Looks like there is a lot of interest in
> robotics with
> > this group, though, and I'd guess that you will get plenty of help
> if you ask.
> > Mike
> >
> > > > At 09:07 AM 3/2/2001 -0800, you wrote:
> > > >
> > > > >So do people not use Pneumatics for robotic applications? I
> thought it was
> > > > >common but if you are saying you cant do positioning
> accurately then maybe
> > > > >not...
> > > > >
> > > > >- Matt
> > > >
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
pnuetronics. It's a small part of the PARKER http://www.parker.com/
company and you may have to search the vendors in your area. I have
found only a few vendors.
They make the small valves that you can use with the Stamp.
Clippard and Bimba and a host of others make the tiny actuators you
are looking for. Check E-bay for some cheaper prices. McMaster
Carr will probably carry small actuators.
Dave
--- In basicstamps@y..., Matt Johnson <matt@p...> wrote:
>
> Thanks Dave, that really helps. What is a good manufacturer for the
> pneumatics used in small time robotics (bore less then 3/4" stroke
of 3")
> And is the feedback basically just a POT? $70 seems cheap for a
prototype.
> Where do you get the stuff?
>
> - Matt
>
> On Mon, 5 Mar 2001 davemucha@j... wrote:
>
> > For automonus robots, it's the air supply. there is just not
> > enough 'power' in a 20 pound tank for more than a little work.
> >
> > For stationry equipment, the cost/power ratio is all in favor the
> > pneumatics. A 20 psi air cylendar, no feedback, capable of
liftng
> > 200 pounds cost about $70.00. Lift time less than one second per
> > foot. Try that with a servo or stepper.
> >
> > But don't try to postion an arm within 0.001" with a pnuematic
> > actuator. The feedback and valving will be much more than the
> > electronics, and the actuator will allow compression of the gas
> > therby making the holding power useless for precision work.
> >
> > Pnuematic industrial actutors, 72" long, for postiioning, not
> > holding, will move 72" in a second, to within 0.001", but cost
> > upwards of $1,000.00 before you buy valves.
> >
> > You CAN get pnuematics to do precision, but at costs more than
> > electroncs. Milling machines and lathes use steppers and ball
> > screws. Much better control. The Heating/ventaling world uses
> > pnuematics, much better bang for the buck when precison in not
> > important.
> >
> > Hope this helps.
> >
> > Dave
> >
> >
> >
> >
> >
> >
> >
> > --- In basicstamps@y..., MIKE WALSH <walsh@c...> wrote:
> > > Matt,
> > > I'll defer to the robot experts on this one. It's an
interesting
> > subject to
> > > follow, but I don't have the time or the resources to add
robotics
> > to my
> > > list of "to-do's". Looks like there is a lot of interest in
> > robotics with
> > > this group, though, and I'd guess that you will get plenty of
help
> > if you ask.
> > > Mike
> > >
> > > > > At 09:07 AM 3/2/2001 -0800, you wrote:
> > > > >
> > > > > >So do people not use Pneumatics for robotic applications?
I
> > thought it was
> > > > > >common but if you are saying you cant do positioning
> > accurately then maybe
> > > > > >not...
> > > > > >
> > > > > >- Matt
> > > > >
> >
> >
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
> >
found this link showing an air valve with this claim...
"This is a fully functional electric valve made with Nitinol. It permits
proportional control of the air or fluid flow. When voltage is applied the
Nitinol inside contracts, opening the valve."
Here's the link
http://www.imagesco.com/catalog/nitinol/nitinol.html#valve
Original Message
From: davemucha@j... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=pQ_egrCqmUDHrfo0RBW_E09h2ffn-BnReR0jWjNz2TaNbPYsTra37VttPiqGRz89k4Bavyj5J_Lo]davemucha@j...[/url
Sent: Monday, March 05, 2001 11:24 AM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] Re: Voltage Controlled Valve - Help!
For automonus robots, it's the air supply. there is just not
enough 'power' in a 20 pound tank for more than a little work.
For stationry equipment, the cost/power ratio is all in favor the
pneumatics. A 20 psi air cylendar, no feedback, capable of liftng
200 pounds cost about $70.00. Lift time less than one second per
foot. Try that with a servo or stepper.
But don't try to postion an arm within 0.001" with a pnuematic
actuator. The feedback and valving will be much more than the
electronics, and the actuator will allow compression of the gas
therby making the holding power useless for precision work.
Pnuematic industrial actutors, 72" long, for postiioning, not
holding, will move 72" in a second, to within 0.001", but cost
upwards of $1,000.00 before you buy valves.
You CAN get pnuematics to do precision, but at costs more than
electroncs. Milling machines and lathes use steppers and ball
screws. Much better control. The Heating/ventaling world uses
pnuematics, much better bang for the buck when precison in not
important.
Hope this helps.
Dave
--- In basicstamps@y..., MIKE WALSH <walsh@c...> wrote:
> Matt,
> I'll defer to the robot experts on this one. It's an interesting
subject to
> follow, but I don't have the time or the resources to add robotics
to my
> list of "to-do's". Looks like there is a lot of interest in
robotics with
> this group, though, and I'd guess that you will get plenty of help
if you ask.
> Mike
>
> > > At 09:07 AM 3/2/2001 -0800, you wrote:
> > >
> > > >So do people not use Pneumatics for robotic applications? I
thought it was
> > > >common but if you are saying you cant do positioning
accurately then maybe
> > > >not...
> > > >
> > > >- Matt
> > >
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
http://www.imagesco.com/articles/airmuscle/AirMuscleDescription01.html
Couldn't you robotics guys find an application here?
Mike
At 01:55 PM 3/5/2001 -0800, you wrote:
>While browsing around the site for a source given for compass modules I
>found this link showing an air valve with this claim...
>
>"This is a fully functional electric valve made with Nitinol. It permits
>proportional control of the air or fluid flow. When voltage is applied the
>Nitinol inside contracts, opening the valve."
>
>Here's the link
>http://www.imagesco.com/catalog/nitinol/nitinol.html#valve