Hi,
Pilots are taught to think in terms of pressure on stick not displacement.
That is part of the reason that the F-16 is built the way it is.
Thats OK, I agree, with one small change:
pilots are not *taught* to think in terms in terms of pressure on stick.
It is the natural way of sensing the
Curtis L. Olson wrote:
Erik Hofman wrote:
Personally, I would be in favor of using angles to describe the
positions of left/right aileron, elevator, rudder and nose/tail wheel.
Please, not for the wheels. Really.
It doesn't probably matter too much for 3d animation if your conversion
factor
Jim Wilson wrote:
This is just what was going through my mind when reading this discussion.
Jon's concern is quite valid, but there are problems. As I work through
these concepts in my mind, I can see that although the current method sounds
more complicated for the 3D animator, having to deal
Jon S Berndt wrote:
On Thu, 16 Dec 2004 20:47:03 -
Jim Wilson wrote:
It might be useful for someone to work through the values as that
would be
report for the various stages of deployment on a 747 flap system. As
Richard
message suggests here the detail required by the 3D modeler is
On Fri, 17 Dec 2004 09:22:17 +0100, Gordan wrote in message
[EMAIL PROTECTED]:
Hi,
Pilots are taught to think in terms of pressure on stick not
displacement. That is part of the reason that the F-16 is built the
way it is.
..this used to be the doctrine in at least the 1980'ies in the
Curtis L. Olson wrote:
Erik Hofman wrote:
Personally, I would be in favor of using angles to describe the
positions of left/right aileron, elevator, rudder and nose/tail wheel.
Please, not for the wheels. Really.
It doesn't probably matter too much for 3d animation if your
On Behalf Of Arnt Karlsen
On Fri, 17 Dec 2004 09:22:17 +0100, Gordan wrote in message
[EMAIL PROTECTED]:
Hi,
Pilots are taught to think in terms of pressure on stick not
displacement. That is part of the reason that the F-16 is built the
way it is.
..this used to be the doctrine
Jon Berndt wrote:
(And If you don't believe me, start to work on the gear animations of
the Fokker-50 in degrees (0 - 90 degrees). If you manage to get that
working we could start talking again).
I think this illustrates the futility of trying to use a one-size-fits-all
animation
strategy. It
Also, ask yourself the question, does the normalized value of, say, 0.5
really correspond to 30 degrees of flaps when the total range is 0 to 60?
It should be, if the FDM does it's thing right.
Erik
Not so fast. Aero tables might be indexed for flaps based on angle. If the
flaps are
Curtis L. Olson wrote:
It doesn't probably matter too much for 3d animation if your conversion
factor get's you close.
There is another thing, all doors, struts and support bars are animated
based on the gear extension. While the main gear extension might be
perfectly valid in degrees,
Jon Berndt wrote:
Also, ask yourself the question, does the normalized value of, say, 0.5
really correspond to 30 degrees of flaps when the total range is 0 to 60?
It should be, if the FDM does it's thing right.
Erik
Not so fast. Aero tables might be indexed for flaps based on angle. If the
Jon Berndt wrote:
good chance
that you're not going to get exactly 30 degrees flaps. The actuator
mechnism probably
won't linearly extend the flaps due to the compound nature of the flap
mechanisms.
If that is the case the FDM should know about it more than anything else
IMHO.
Boy, do I enjoy a vigorous debate, especially when I am right. Unfortunately,
in this
case, I appears that I did not consider all the needs of the animation system.
Neither one
should have to be designed to make up for something the other doesn't do. So I
think the
best thing to do, as we've
On Fri, 17 Dec 2004 07:32:04 -0600, Jon wrote in message
[EMAIL PROTECTED]:
On Behalf Of Arnt Karlsen
On Fri, 17 Dec 2004 09:22:17 +0100, Gordan wrote in message
[EMAIL PROTECTED]:
Hi,
Pilots are taught to think in terms of pressure on stick not
displacement. That is part
Jon Berndt writes:
Boy, do I enjoy a vigorous debate, especially when I am right. Unfortunately,
in this
case, I appears that I did not consider all the needs of the animation
system. Neither one
should have to be designed to make up for something the other doesn't do. So
I think the
Hi Jon,
output laterally, on the pedals, and front/back on the stick. I think that's
why the
control law diagrams I have seen use pilot stick force as the input unit. One
hundred
percent of the control law diagrams I have seen that include pilot inputs use
force.
Once more, do not make general
On Fri, 17 Dec 2004 15:26:26 +0100
Gordan Sikic [EMAIL PROTECTED] wrote:
Hi Jon,
Once more, do not make general statements, based on a few examples.
Jon wrote:
One hundred percent of the control law diagrams ...
emphasisI have seen/emphasis
that include pilot inputs use force.
There are _many_
Jon Berndt wrote:
No, the FDM doesn't care about anything but commanded flap position - which will be taken
to actual position through the FCS, but with JSBSim actuator dynamics are not required to
be modeled. Commanded and actual positions are in degrees. As I said before, does 30
degrees flaps
Jon Berndt wrote:
Boy, do I enjoy a vigorous debate, especially when I am right. Unfortunately, in this
case, I appears that I did not consider all the needs of the animation system. Neither one
should have to be designed to make up for something the other doesn't do. So I think the
best thing to
On Fri, 17 Dec 2004 10:07:47 -0600
Curtis L. Olson [EMAIL PROTECTED] wrote:
Jon, the problem is: how does the interface know how to normalize
the control surface positions? Where does it read the maximum limits
from? The FDM is really the only piece that is going to know this
information.
On Fri, 17 Dec 2004 10:05:04 -0600
Curtis L. Olson [EMAIL PROTECTED] wrote:
The FDM may choose to carry along with that abstraction (which makes
sense) because you are concerned with getting the right performance
when the lever is in the 30 degree position. It all works out in the
end, but
: Re: [Flightgear-devel] control surface normalization
Hi,
Pilots are taught to think in terms of pressure on stick not displacement.
That is part of the reason that the F-16 is built the way it is.
Thats OK, I agree, with one small change:
pilots are not *taught* to think in terms
On Thursday 16 December 2004 21:17, Jon S Berndt wrote:
[snip...]
Also, ask yourself the question, does the normalized value of,
say, 0.5 really correspond to 30 degrees of flaps when the
total range is 0 to 60?
Are you not assuming a linear transition here? It doesn't have
to be.
LeeE
On Thursday 16 December 2004 22:08, Gordan Sikic wrote:
[snip...]
(about F16)
AFAIK, it has nonmoving joystick, and force transducers, and
it is normal for that plane to ise output from the
transduced as a input.
The original HOTAS non-moving sticks in the development a/c were
changed to
Lee Elliott wrote:
On Thursday 16 December 2004 21:17, Jon S Berndt wrote:
[snip...]
Also, ask yourself the question, does the normalized value of,
say, 0.5 really correspond to 30 degrees of flaps when the
total range is 0 to 60?
Are you not assuming a linear transition here?
On Fri, 17 Dec 2004 21:51:56 -
Vivian Meazza [EMAIL PROTECTED] wrote:
How do FDMs handle Fowler flaps? i.e. the first part of the action
extends the flap rearwards without any rotation, acting only to
increase wing area, then for the rest of the action rotate downwards?
Easy enough to 3d
On Friday 17 December 2004 21:51, Vivian Meazza wrote:
Lee Elliott wrote:
On Thursday 16 December 2004 21:17, Jon S Berndt wrote:
[snip...]
Also, ask yourself the question, does the normalized value
of, say, 0.5 really correspond to 30 degrees of flaps when
the total range is 0 to
Lee Elliott wrote
[snip...]
How do FDMs handle Fowler flaps? i.e. the first part of the
action extends the flap rearwards without any rotation, acting
only to increase wing area, then for the rest of the action
rotate downwards?
Easy enough to 3d model with a normalized input:
On Fri, 17 Dec 2004 22:59:35 -
Vivian Meazza [EMAIL PROTECTED] wrote:
Lee Elliott wrote
[snip...]
How do FDMs handle Fowler flaps? i.e. the first part of the
action extends the flap rearwards without any rotation, acting
only to increase wing area, then for the rest of the action
Would you mind repeating your original intention?
Ampere
___
Flightgear-devel mailing list
[EMAIL PROTECTED]
http://mail.flightgear.org/mailman/listinfo/flightgear-devel
2f585eeea02e2c79d7b1d8c4963bae2d
Would you mind repeating your original intention, Jon?
Ampere
___
Flightgear-devel mailing list
[EMAIL PROTECTED]
http://mail.flightgear.org/mailman/listinfo/flightgear-devel
2f585eeea02e2c79d7b1d8c4963bae2d
Would you mind repeating your original intention, Jon?
Ampere
I started out with the question: Can anyone recommend a good digital
camcorder? and it
went downhill from there.
;-)
Here was my original question: I'd like to remove the code that normalizes
angular
measurement, but I am told
Hi,
I agree with Norman. As long as control system is of concern, it is much
better to use normalized units.
surface deflections in degrees, and for good reason: it's natural, it's
physical. From the point of view of JSBSim, normalized aerosurface
Degrees are not natural, nor physical. We may
Curtis L. Olson wrote:
I think we are limiting the discussion here to only flying control
surface positions, i.e.
- left aileron deflection
- right aileron deflection
- elevator deflection
- rudder deflection
- nose/tail wheel deflection.
I wouldn't like this one to end up in degrees. Not because
Erik Hofman wrote:
Personally, I would be in favor of using angles to describe the
positions of left/right aileron, elevator, rudder and nose/tail wheel.
Please, not for the wheels. Really.
It doesn't probably matter too much for 3d animation if your conversion
factor get's you close. However,
Hi,
Control law block diagrams I have seen take stick input in pounds force (pilot
inputs) and
output in degrees to actuators. I've never seen one that output control
commands to an
aerosurface actuator in a range from 0 to 1. Have you?
I have seen (and I've seen more than few) control law
On Thu, 16 Dec 2004 11:15:52 -0800
Richard Harke [EMAIL PROTECTED] wrote:
A rotation whether in degrees or radians only makes sense if the
axis of rotation is specified. This would have to be on a per aircraft
basis. Also I'm sure that many if not most control surfaces do not
simply rotate
On Thu, 16 Dec 2004 18:21:24 +0100
Gordan Sikic [EMAIL PROTECTED] wrote:
I have seen (and I've seen more than few) control law diagrams
taking some generalized input (0-1 range), taking target speed, or
attitude, or something,... but havent seen any, taking as a input
force that pilot has to
On Thu, 16 Dec 2004 20:47:03 -
Jim Wilson [EMAIL PROTECTED] wrote:
Jon's concern is quite valid, but there are problems. As I work
through
these concepts in my mind, I can see that although the current
method sounds
more complicated for the 3D animator, having to deal with the real
Jon S Berndt said:
Also, ask yourself the question, does the normalized value of, say,
0.5 really correspond to 30 degrees of flaps when the total range is 0
to 60?
No telling. How many angles can you discern at 50 meters on a 1600 pixel
screen (not to mention 800)? :-)
Also, to have
Hi Jon,
I see you are really mad :)
Look here at the X-15 data and FCS diagram:
http://jsbsim.sourceforge.net/X-15Aero.html
The USAF F-16 (Block 40) FCS diagram is the same way: stick force is the
input. Same with Space Shuttle control Law diagrams.
The JSBSim X-15 model simulates the X-15
Hi,
I agree with Norman. As long as control system is of concern, it is much
better to use normalized units.
Control law block diagrams I have seen take stick input in pounds force (pilot
inputs) and
output in degrees to actuators. I've never seen one that output control
commands to an
On Thursday 16 December 2004 04:06, Jon Berndt wrote:
True, I've seen both. JSBSim has used both, and we accept both, but
normalized units are anything but normal - you have to provide a range
for it to mean anything, and as far as I can tell, there is no standard
here. It's defined on a
Richard Harke said:
A rotation whether in degrees or radians only makes sense if the axis
of rotation is specified. This would have to be on a per aircraft basis. Also
I'm sure that many if not most control surfaces do not simply rotate about
a single axis but involve sliding motion and
Dec 2004 23:08:30 +0100
To: FlightGear developers discussions [EMAIL PROTECTED]
Subject: Re: [Flightgear-devel] control surface normalization
Hi Jon,
I see you are really mad :)
Look here at the X-15 data and FCS diagram:
http://jsbsim.sourceforge.net/X-15Aero.html
The USAF F-16 (Block
And the Simgear 3D animation code is all about taking those normalized values
and translating them to a representation of degrees movement. On the surface,
this doesn't make sense to me either.
Changing this on the FlightGear end and making the other FDMs compatible is
quite a task though.
Jim Wilson writes:
Jon Berndt said:
Do 3D models use a normalized range to model aerosurface rotation, or
actual degree
magnitude? I've been looking at the JSBSim flight control code and the
addition of the
code that normalizes aerosurface (elevator, aileron, etc.) rotation
positions
On Wed, 15 Dec 2004 12:01:23 -0500
Norman Vine [EMAIL PROTECTED] wrote:
It is realy quite simple
you either have
1) an abstract class with 'Normalized units'
class Control
or
2) a bunch of specalized classes
class Angle_Controller
class Toggle_Controller
class Percentage_Controller
etc
On Wed, 15 Dec 2004 12:30:25 -0500
Norman Vine [EMAIL PROTECTED] wrote:
Curtis L. Olson writes:
I think we are limiting the discussion here to only flying control
surface positions, i.e.
As you point out those are only a small subset of the
Control class abstaction.
So specialize these if
Jon S Berndt wrote:
-Original Message-
From: [EMAIL PROTECTED] [mailto:flightgear-devel-
[EMAIL PROTECTED] On Behalf Of
Sent: 15 December 2004 17:34
To: FlightGear developers discussions
Subject: Re: [Flightgear-devel] control surface normalization
On Wed, 15 Dec 2004 17:21:13
But when it comes to flaps, slats, and speed brakes it's not nearly so
simple. There, normalized values make a lot of sense. But then to
follow along with the logic, do we want to output our control surface
positions in one consistent way, or do we want to mix and match units,
and if we
On Wednesday 15 December 2004 18:22, Vivian Meazza wrote:
Jon S Berndt wrote:
-Original Message-
From: [EMAIL PROTECTED]
[mailto:flightgear-devel- [EMAIL PROTECTED] On Behalf
Of
Sent: 15 December 2004 17:34
To: FlightGear developers discussions
Subject: Re: [Flightgear-devel
On Wed, 15 Dec 2004 11:16:32 -0800
John Wojnaroski [EMAIL PROTECTED] wrote:
And then there are slats that deploy as a function of airspeed/AOA;
e.g; Sabreliners
This is irrelevant, also - at least for JSBSim. In this case, the
slats would be automatically deployed as directed by the flight
- Original Message -
From: Jon S Berndt [EMAIL PROTECTED]
To: FlightGear developers discussions [EMAIL PROTECTED]
Sent: Wednesday, December 15, 2004 11:30 AM
Subject: Re: [Flightgear-devel] control surface normalization
On Wed, 15 Dec 2004 11:16:32 -0800
John Wojnaroski [EMAIL
Jon S Berndt writes:
Absolutely. And JSBSim is used by more than FlightGear - which leads
to part of the concern I have. FlightGear should not require the FDM
to massage values that it should be massaging itself.
Just need a translation layer
IIRC 'Normalized Control Units' have been in
John Wojnaroski wrote:
Not quite, these slats are air-loaded; i.e, there is no mechanical,
hydraulic, or electrical actuation of the slats. There is no command or
logic in the FCS, air data computer, or crew activation to extend the slats.
Part of the walk-around is to physically push the slats up
Curt wrote:
But Jon, this statement seems to run counter to your overall
argument. Slats at least on many of the aircraft I've seen deploy
linearly. In other words they are on some sort of rail mechanism
and slide out away from the leading edge of the wing in a linear
motion. They aren't
Vivian Meazza writes:
Perhaps some of our longer standing developers can shed some light on the
background to this important decision.
This was the easiest way to implement the system at the time insuring that
only 'sane' values were ever passed. ie 'clamped'
An alternative method would be
Hi,
Since flightgears animation engine can now use interpolation tables where you
can map any range linearly to any other range I think that normalization is
not that important anymore.
Anyway, my F-18 uses degrees for every *internally* used surface deflection.
The values used for
Jon Berndt said:
Do 3D models use a normalized range to model aerosurface rotation, or
actual degree
magnitude? I've been looking at the JSBSim flight control code and the
addition of the
code that normalizes aerosurface (elevator, aileron, etc.) rotation
positions confuses
the code, and
On Wed, 15 Dec 2004 10:41:27 -0500
Norman Vine [EMAIL PROTECTED] wrote:
Jim Wilson writes:
And the Simgear 3D animation code is all about taking those
normalized values
and translating them to a representation of degrees movement. On
the surface,
this doesn't make sense to me either.
I can
Jon S Berndt wrote:
Your example is irrelevant. Fluid pressure cannot be seen. Amps cannot
be seen. Neither Amps nor fluid pressure are reported on a zero to one
scale. Aerosurfaces can be drawn and seen, and that's not done on a
zero to one basis either. Like I said, there are some things that
Curtis L. Olson writes:
Jon S Berndt wrote:
Your example is irrelevant. Fluid pressure cannot be seen. Amps cannot
be seen. Neither Amps nor fluid pressure are reported on a zero to one
scale. Aerosurfaces can be drawn and seen, and that's not done on a
zero to one basis either.
Norman Vine wrote:
Curtis L. Olson writes:
Jon S Berndt wrote:
Your example is irrelevant. Fluid pressure cannot be seen. Amps cannot
be seen. Neither Amps nor fluid pressure are reported on a zero to one
scale. Aerosurfaces can be drawn and seen, and that's not done on a
zero to one
Jon Berndt
Do 3D models use a normalized range to model aerosurface rotation, or
actual degree
magnitude? I've been looking at the JSBSim flight control code and the
addition of the
code that normalizes aerosurface (elevator, aileron, etc.) rotation
positions confuses
the code, and appears
Curtis L. Olson writes:
I think we are limiting the discussion here to only flying control
surface positions, i.e.
As you point out those are only a small subset of the
Control class abstaction.
So specialize these if esired but
IMO the 'slippery slope principal' is in play here
BTW
On Wed, 15 Dec 2004 17:21:13 -
Vivian Meazza [EMAIL PROTECTED] wrote:
A quick search revealed that most, if not all, the 3d models in the
current inventory use normalized values for animating the control
surfaces.
See, this further raises a red flag for me. How does the 3D model know
how
On Wed, 15 Dec 2004 18:22:30 -
Vivian Meazza [EMAIL PROTECTED] wrote:
There are several points here.
1. The fact is that most 3d (I think all, but I haven't checked)
rightly or wrongly already use normalized values. It would be a
significant task to change.
Agreed. This is a consideration.
Jon S Berndt writes:
This is irrelevant, also - at least for JSBSim.
That is an excellent observation
FGFS is more then JSBSim though :-)
Cheers
Norman
___
Flightgear-devel mailing list
[EMAIL PROTECTED]
Jon S Berndt wrote:
On Wed, 15 Dec 2004 11:16:32 -0800
John Wojnaroski [EMAIL PROTECTED] wrote:
And then there are slats that deploy as a function of airspeed/AOA;
e.g; Sabreliners
This is irrelevant, also - at least for JSBSim. In this case, the
slats would be automatically deployed as
On Wed, 15 Dec 2004 14:51:07 -0500
Norman Vine [EMAIL PROTECTED] wrote:
Jon S Berndt writes:
This is irrelevant, also - at least for JSBSim.
That is an excellent observation
FGFS is more then JSBSim though :-)
Norman
Absolutely. And JSBSim is used by more than FlightGear - which leads
to part
On Wed, 15 Dec 2004 14:51:07 -0500
Norman Vine [EMAIL PROTECTED] wrote:
Jon S Berndt writes:
This is irrelevant, also - at least for JSBSim.
That is an excellent observation
FGFS is more then JSBSim though :-)
Norman
Absolutely. And JSBSim is used by more than FlightGear - which leads
to part
On Wed, 15 Dec 2004 14:51:07 -0500
Norman Vine [EMAIL PROTECTED] wrote:
Jon S Berndt writes:
This is irrelevant, also - at least for JSBSim.
That is an excellent observation
FGFS is more then JSBSim though :-)
Norman
Absolutely. And JSBSim is used by more than FlightGear - which leads
to part
Jon S Berndt wrote:
On Wed, 15 Dec 2004 18:22:30 -
Vivian Meazza [EMAIL PROTECTED] wrote:
There are several points here.
1. The fact is that most 3d (I think all, but I haven't checked)
rightly or wrongly already use normalized values. It would be a
significant task to change.
Vivian Meazza
3. For consistency, and remember that some 3d models are used with
both YASim and other FDMs, we need normalized values.
This is just plain wrong. If an aircraft can deflect the elevator +/-
30 degrees that's the way it is. Regardless of FDM. We are talking
about
75 matches
Mail list logo
