[simpits-tech] Force Feedback
Craig Rochester
simpits-tech@simpits.org
Fri, 24 Jan 2003 22:40:32 -0500
This is a multi-part message in MIME format.
------=_NextPart_000_0003_01C2C3F9.9A2934E0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: 7bit
Hi Keenan,
Yes... a "V/P"(aka E/P), voltage to pressure transducer, takes a variable voltage signal and outputs a
proportional pressure. A typical unit will take 0-10 VDC and output 3-15 psi. Some units can be re-spanned
to output close to 0 psi at 0 V. Here's a rig I use for my G-suit:
http://pages.zdnet.com/johncraigrochester/sitebuildercontent/sitebuilderpictures/servo_regulator.jpg
As the servo rotates 0-180 deg, the rod is driven 2 x "d". Where "d" is the offset of the bearing from the
servo axis. The output speed is limited by the servo rotational speed. Also the pressure out is not linear
as a function of servo angle( sine(angle)), but I can scale the software.
A real V/P is faster and more precise, although the servo rig has a precision of better than 0.1 psi with
surprisingly little hysteresis (up/down lag). The metal on metal action of the bearing on the rod yields
essentially no play. The bearing allows the servo to rotate with minimal friction.
Craig R.
-----Original Message-----
From: simpits-tech-admin@simpits.org [mailto:simpits-tech-admin@simpits.org]On Behalf Of Keenan Akin
Sent: Friday, January 24, 2003 9:31 PM
To: simpits-tech@simpits.org
Subject: Re: [simpits-tech] Force Feedback
Craig,
Tell me more about these transducers. If you vary the input voltage, the outlet pressure varies
proportionately?
Keenan
------=_NextPart_000_0003_01C2C3F9.9A2934E0
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE></TITLE>
<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Dwindows-1252">
<META content=3D"MSHTML 6.00.2800.1126" name=3DGENERATOR></HEAD>
<BODY>
<DIV><SPAN class=3D15222303-25012003><FONT face=3DArial size=3D2>Hi=20
Keenan,</FONT></SPAN></DIV>
<DIV><SPAN class=3D15222303-25012003><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D15222303-25012003><FONT face=3DArial size=3D2>Yes... =
a "V/P"(aka=20
E/P), voltage to pressure transducer, takes a variable voltage =
signal and=20
outputs a proportional pressure. A typical unit will take 0-10 VDC =
and=20
output 3-15 psi. Some units can be re-spanned to output close to 0 =
psi=20
at 0 V. Here's a rig I use for my =
G-suit:</FONT></SPAN></DIV>
<DIV><SPAN class=3D15222303-25012003><FONT face=3DArial color=3D#0000ff =
size=3D2><A=20
href=3D"http://pages.zdnet.com/johncraigrochester/sitebuildercontent/site=
builderpictures/servo_regulator.jpg">http://pages.zdnet.com/johncraigroch=
ester/sitebuildercontent/sitebuilderpictures/servo_regulator.jpg</A></FON=
T></SPAN></DIV>
<DIV><SPAN class=3D15222303-25012003><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D15222303-25012003><FONT face=3DArial size=3D2>As the =
servo rotates=20
0-180 deg, the rod is driven 2 x "d". Where "d" is the offset of =
the=20
bearing from the servo axis. The output speed is limited by the =
servo=20
rotational speed. Also the pressure out is not linear as a =
function of=20
servo angle( sine(angle)), but I can scale the =
software.</FONT></SPAN></DIV>
<DIV><SPAN class=3D15222303-25012003><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D15222303-25012003><FONT face=3DArial size=3D2>A real =
V/P is faster=20
and more precise, although the servo rig has a precision of better than =
0.1 psi=20
with surprisingly little hysteresis (up/down lag). The metal on =
metal=20
action of the bearing on the rod yields essentially no play. =
The=20
bearing allows the servo to rotate with minimal =
friction.</FONT></SPAN></DIV>
<DIV><SPAN class=3D15222303-25012003><FONT face=3DArial=20
size=3D2></FONT></SPAN> </DIV>
<DIV><SPAN class=3D15222303-25012003><FONT face=3DArial size=3D2>Craig=20
R.</FONT></SPAN></DIV>
<BLOCKQUOTE>
<DIV class=3DOutlookMessageHeader><FONT face=3D"Times New Roman"=20
size=3D2>-----Original Message-----<BR><B>From:</B>=20
simpits-tech-admin@simpits.org =
[mailto:simpits-tech-admin@simpits.org]<B>On=20
Behalf Of</B> Keenan Akin<BR><B>Sent:</B> Friday, January 24, 2003 =
9:31=20
PM<BR><B>To:</B> simpits-tech@simpits.org<BR><B>Subject:</B> Re:=20
[simpits-tech] Force Feedback<BR><BR></FONT></DIV>Craig,<BR><BR>Tell =
me more=20
about these transducers. If you vary the input voltage, the =
outlet=20
pressure varies proportionately?=20
<BR><BR>Keenan<BR><BR></BLOCKQUOTE></BODY></HTML>
------=_NextPart_000_0003_01C2C3F9.9A2934E0--