[simpits-tech] May the Force Feedback be with you...
Ken Schlote
simpits-tech@simpits.org
Thu, 6 Feb 2003 05:53:46 -0800 (PST)
--0-1102630421-1044539626=:36782
Content-Type: text/plain; charset=us-ascii
OK, I have a cylinder in front of me and by restricting the air on one port makes it harder to move in or out.That is all you need. But the need to vent the air to the other side I don't follow. Just restricting the air from going in or out of one port will do the same thing. Then have the FF solenoid pluse the air into the other side.
But if you are going for the most realistic then you need to make the cylinder feedback push back on the cylinder (stick) to the trimmed point of the aircraft until you retrim the aircraft at which time the forces are neutral. The forces want to center the stick to the trim point. Any movement will require force in that direction proportional to the air speed and by trimming you relieve the force pushing back.
Ken
Keenan Akin <kakin@yhti.net> wrote:Ken,
The servo operated valve modulates the air venting from one side of the
cylinder to the other. When the servo is sensing low airspeeds the
valve permits relatively free flow (the stick can be moved with light
force). As the airspeed increases, the valves starts restricting the
flow proportionally, requiring a higher force to move the stick
(representing aero forces on the control surfaces). Remember, I am
building a WWII fighter, not a fly-by-wire jet. The solenoid valve is
just there to provide pressure "pulses" in response to force feedback
signals.
Hope I made sense.
Keenan
Ken Schlote wrote:
> Keenan,
>
> I'm not quite sure why you are using air pressure to increase the
> force of a stick. If you are going to use a cylinder then just adjust
> the flow entering or leaving the cylinder. Example: By closing the
> rear port you either have to pull a vacuum or pressurize the cylinder
> which stops you from moving the shaft because the air can not escape
> or enter. Adjusting the flow leaving or entering allows the shaft to
> move but with more force.
>
> A "V notch port" will do the job. (see attachment). As the V notch
> plug is pulled out of the port more air can escape or enter letting
> the shaft move with less force. As it moves in, the force increases
> because the size of the port decreases. This can all be done with one
> servo and cylinder per axis.
>
> Hope this helps. Questions?
>
> Ken
>
> "Akin, Keenan L" wrote:
>
> Okay folks,
>
> Here is my current concept of a pneumatic force feedback actuator
> for my pit. There would be two of these actuators attached to the
> stick (one pitch axis, one roll axis).
>
> <>
> The servo driven valve uses airspeed data to modulate the airflow
> from one side of the cylinder to the other (caused by moving the
> stick). For example, at higher airspeeds, the flow will be
> restricted, causing the stick to be harder to move.
>
> The solenoid valve ports pressurized air to one side of the
> cylinder or to the other only when a force feedback signal directs
> it. Otherwise, it is closed.
>
> Thoughts? Questions?
>
> Keenan
> > ATTACHMENT part 2 image/gif name=ffactuator.gif
>
>
> ------------------------------------------------------------------------
> Do you Yahoo!?
> Yahoo! Mail Plus
> -
> Powerful. Affordable. Sign up now
>
> ------------------------------------------------------------------------
>
>
>
---------------------------------
Do you Yahoo!?
Yahoo! Mail Plus - Powerful. Affordable. Sign up now
--0-1102630421-1044539626=:36782
Content-Type: text/html; charset=us-ascii
<P>OK, I have a cylinder in front of me and by restricting the air on one port makes it harder to move in or out.That is all you need. But the need to vent the air to the other side I don't follow. Just restricting the air from going in or out of one port will do the same thing. Then have the FF solenoid pluse the air into the other side.
<P>But if you are going for the most realistic then you need to make the cylinder feedback push back on the cylinder (stick) to the trimmed point of the aircraft until you retrim the aircraft at which time the forces are neutral. The forces want to center the stick to the trim point. Any movement will require force in that direction proportional to the air speed and by trimming you relieve the force pushing back.
<P>Ken
<P> <B><I>Keenan Akin <kakin@yhti.net></I></B> wrote:
<BLOCKQUOTE style="BORDER-LEFT: #1010ff 2px solid; MARGIN-LEFT: 5px; PADDING-LEFT: 5px">Ken,<BR><BR>The servo operated valve modulates the air venting from one side of the <BR>cylinder to the other. When the servo is sensing low airspeeds the <BR>valve permits relatively free flow (the stick can be moved with light <BR>force). As the airspeed increases, the valves starts restricting the <BR>flow proportionally, requiring a higher force to move the stick <BR>(representing aero forces on the control surfaces). Remember, I am <BR>building a WWII fighter, not a fly-by-wire jet. The solenoid valve is <BR>just there to provide pressure "pulses" in response to force feedback <BR>signals.<BR><BR>Hope I made sense.<BR><BR>Keenan<BR><BR><BR>Ken Schlote wrote:<BR><BR>> Keenan,<BR>><BR>> I'm not quite sure why you are using air pressure to increase the <BR>> force of a stick. If you are going to use a cylinder then just adjust <BR>> the flow entering or leaving the cylinder. Example: By closing the <BR>> rear port you either have to pull a vacuum or pressurize the cylinder <BR>> which stops you from moving the shaft because the air can not escape <BR>> or enter. Adjusting the flow leaving or entering allows the shaft to <BR>> move but with more force.<BR>><BR>> A "V notch port" will do the job. (see attachment). As the V notch <BR>> plug is pulled out of the port more air can escape or enter letting <BR>> the shaft move with less force. As it moves in, the force increases <BR>> because the size of the port decreases. This can all be done with one <BR>> servo and cylinder per axis.<BR>><BR>> Hope this helps. Questions?<BR>><BR>> Ken<BR>><BR>> "Akin, Keenan L" <KEENAN.L.AKIN@BOEING.COM>wrote:<BR>><BR>> Okay folks,<BR>><BR>> Here is my current concept of a pneumatic force feedback actuator<BR>> for my pit. There would be two of these actuators attached to the<BR>> stick (one pitch axis, one roll axis).<BR>><BR>> <><BR>> The servo driven valve uses airspeed data to modulate the airflow<BR>> from one side of the cylinder to the other (caused by moving the<BR>> stick). For example, at higher airspeeds, the flow will be<BR>> restricted, causing the stick to be harder to move.<BR>><BR>> The solenoid valve ports pressurized air to one side of the<BR>> cylinder or to the other only when a force feedback signal directs<BR>> it. Otherwise, it is closed.<BR>><BR>> Thoughts? Questions?<BR>><BR>> Keenan<BR>> > ATTACHMENT part 2 image/gif name=ffactuator.gif <BR>><BR>><BR>> ------------------------------------------------------------------------<BR>> Do you Yahoo!?<BR>> Yahoo! Mail Plus <BR>> - <BR>> Powerful. Affordable. Sign up now <BR>> <BR>> ------------------------------------------------------------------------<BR>><BR>> <?xml:namespace prefix = cid /><cid:part1.00070607.06050406@netscape.com><BR>><BR><BR></BLOCKQUOTE></cid:part1.00070607.06050406@netscape.com><p><br><hr size=1>Do you Yahoo!?<br>
<a href="http://rd.yahoo.com/mail/mailsig/*http://mailplus.yahoo.com">Yahoo! Mail Plus</a> - Powerful. Affordable. <a href="http://rd.yahoo.com/mail/mailsig/*http://mailplus.yahoo.com">Sign up now</a>
--0-1102630421-1044539626=:36782--