Old calculation was
output = input * gain
and is now
output = (input-reference) * gain
Note: the PI(D) controller use (reference-input) which effectively reverses the sign. Our notation was picked for backwards compatibility to not break the myriads of <filter> elements currently existing.
All the rest is some code cleanup.
"logic filters" use well known conditions to drive output properties. Example for bax = baz & (foo | bar).
<logic>
<name>my first logic element</name>
<input>
<or>
<property>foo</property>
<property>bar</property>
</or>
<property>baz</property>
</input>
<output>bax</output>
</logic>
Supports various new editing features, including dragging to re-order, and
+/- keys to adjust the target altitude for a waypoint. Also displays some
additional information, and will display *even* more once I land airways/
SID/STAR support.
- default to an invalid altitude in routes, instead of cruise altitude (temporarily)
- only set an altitude on the autopilot, if valid
- only add departure airport/runway to the route, if not airborne
- allow multiple <autopilot> elements within an aircraft. All autopilot live in an individual FGXMLAutopilot subsystem which run within a subsystem group now.
* When the nav-radio is slaved, calculated radial/target-hdg-deg
(needed by some autopilot logic)
* Handle editing (including deletion) of route waypoints correctly,
including deleting the active waypoint
* Add a signal to the route manager when the last wpt is reached, and
use it in the GPS to revert to OBS mode.
* Change the altitude handling to use the specified cruise altitude
* Fix a bug where autopilot/locks/altitude was treated as a boolean
<abs>true</abs>
for input elements.
If set to true, the input value is filtered thru fabs() function.
Defaults to false if absent, so there is no impact for existing configurations
- a refactoring of the route manager to reduce indentation and duplication
- created a helper method to generate the ETA strings
- created a helper to update target_altitude and altitude_set when the active wp0 changes
- used early returns to make update() easier to follow
- removed spurious includes in both header and source file
Attached patch updates the route-manager to use FGPositioned to search
for waypoints, instead of a manual airport / fix / navaid search. This
is good because it's now using the 'strictly closest' match, rather
than arbitrarily picking a distant fix over a nearby navaid. In my
case, the TLA VOR is significant to several EGPH procedures, but also
happens to be the ident of a fix a long, long way away.
Also updates the FGPositioned class to stop using Point3D, partly
because it's deprecated and partly because I had misunderstood the
interface and was using it wrong. For now, all FGPositioned distance
checks use SGGeodesy::inverse, which is accurate but inefficient. Once
FGPositioned queries are used for something on a hot path, I'll
probably store the cartesian position as well as the geodetic, to make
these checks fast.
Here's part 2 - converting FGFix (the simplest one) to be both heap-based and inherit FGPositioned. One minor benefit from this is replacing some dangerous code in FGFixList which used to return the address of an iterator member ('&it->second'). To keep the diff a sensible size, I'm not updating the callers to use the richer FGPositioned types - i.e replacing separate lat/lon handling with SGGeod. I will make those cleanups, but in future patches.
- this exposed a bizarre issue on Mac where dragging in <AGL/agl.h> in
extensions.hxx was pulling in all of Carbon to the global namespace
- very scary. As a result, I now need to explicitly include CoreFoundation
in fg_init.cxx.
- change SG_USING_STD(x) to using std::x
SimGear change. It changes all the SG_xxxx to be the 'real' includes, and gets
rid of many #ifdef SG_HAVE_STD_INCLUDES. As an added bonus, rather than
replacing 'SG_USING_NAMESPACE(std)' with 'using namespace std', I just fixed
the small number of places to use std:: explicitly. So we're no longer polluting
the global namespace with the entire contents of std, in many cases.
There is one more 'mechanical' change to come - getting rid of SG_USING_STD(X),
but I want to keep that separate from everything else. (There's another
mechnical change, replacing <math.h> with <cmath> and so on *everywhere*, but
one step at a time)
Attached patch adds support for multiple FIXes with the same name.
Applies to both branches.
New functionality is in query_and_offset, which now returns the FIX
closest to the passed in location.
Updated route manager to take advantage of this.
Otherwise, query functions return an unspecified member from the set
of identically named FIXes. (This was previously the one occurring
last in the database file, but I don't think anybody counted on that.)
Thanks to Vivian Meazza for debugging this. The output deque for
FGDigitalFilter was not being kept long enough for the
doubleExponential filter. Reads from output[1] could cause a crash.
Lee has added two new filter types, "gain" and "reciprocal". These filters can
read their gain factor from a property. In the process we also added minimum
and maximum output clamps that are applicable to all filters.
I added the ability to configure adaptive controllers i.e. the controller gain
can be tied to a property, so that it can be changed at runtime. This
requires a change in the xml structure of the autopilot configuration file:
<Kp>
<prop>/autopilot/KAP140/settings/ROL/Kp</prop>
<value>0.10</value>
</Kp> <!-- proportional gain -->
The old method <Kp>0.10</Kp> still works so as to not break all existing
autopilots, but it will output a warning to use the new method.
Please find attatched a new version of xmlauto.cxx.
Remove the call to build() in reinit(). This prevents build() from being
called twice when Reload Autopilot is selected from the Debug menu.
I've also added the ability to define an enabled property for the filters.
It's used like the PID controllers. If there is no enabled tag then the
filter defaults to enabled so that nothing should get broken by this change.
This ability can be used to create a filter between the output of a PID
controller and the property that it controls (a control surface). By putting
a noise spike filter between the output of a controller and the control
surface that it controls, we can simulate the limited movement rate that is
inherent in autopilot servos.
autopilot with the servos off. In otherwords, the computer goes through the
motions of computing the desired behavior (pitch or roll) but doesn't actually
drive the outputs. This is potentially useful when implimenting a flight
director.
SGPropertyNode to guarded ones. This is also done for JSBSim/JSBSim.hxx,
for which JSB had given explicit permission a while ago. I postponed that
back then, but now is the time.
The ufo sets this to a very low value, "serious" aircraft (which don't want this
unrealistic automatism at all) set it to a very high value, and those that don't
care ... don't need to care.
there was the situation where four directories contained jst two files,
of which three directories were aircraft related, and one directory contained
test code from Curt that might be better of in SimGear anyhow.
This is just a patch to move a bunch of files to new locations. In case of
local changes to any of them you can do the following:
move replay.[ch]xx from src/Replay to src/Aircraft
move control.[ch]xx from src/Control to src/Aircraft
move ssgEntityArray.[ch]xx from src/Objects to simgear/screen
In addition it has been decided only to use .[ch]xx files in all directories
unless it's contained within an FDM specific directory, in which case the
author is free to do whatever (s)he wants.
In this repspect the following files have been renamed in src/Multiplayer:
tiny_xdr.[ch]pp has become tiny_xdr.[ch]xx
multiplaymgr.[ch]pp has become multiplaymgr.[ch]xx
* Use "const string&" rather than "string" in function calls when appropriate.
* Use "const Point3D&" instead of "Pint3D" in function calls when appropriate.
* Improved course calculation in calc_gc_course_dist()
* Safer thread handling code.
Vassilii Khachaturov:
Dont use "const Point3D&" for return types unless you're absolutely sure.
Erik Hofman:
* Use SGD_(2)PI(_[24]) as defined in simgear/constants.h rather than
calculating it by hand every time.
I found that all the current users of the companion
function, findByFreq() actually did assume radians despite the misleading
comment in the .hxx and .cxx saying it's degrees. I've fixed the
comment now, and no longer change the Navaids code. The new Navaids user
in NewWaypoint() is now passing radians to the findByIdent().
Note that along with fixing the comments in the navlist.hxx, I removed
an obsolete method findByLoc() declaration (there is no definition
anywhere).
I've prepared a patch as suggested by Hans-Georg Wunder and Jeff McBride.
In addition I've removed the ability to completely leave out the integral
action by setting Ti to zero. The velocity form of the PID algorithm _needs_
the integral action.
>> Hello List,
>>
>> I think there's a small bug in the moving-average filter in
>> xmlauto.cxx
>>
>> I noticed that the output from it was always out a bit and
>> checking with a calculator showed that it seemed to be dividing
>> by the number of samples + 1 instead of just the number of
>> samples.
>>
>> subtracting 1 from 'samples' in line 702 seems to fix the problem
>> and as 'samples' doesn't seem to be used elsewhere I think it's
>> safe. Possibly implies that the number of samples may be one
>> less than specified but I'm not familiar enough with c++ to spot
>> it.
Roy Ovesen:
You are right. I would suggest resizing input[] to (samples + 1) instead.
Change lines 654 and 661 to:
input.resize(samples + 1, 0.0);
That way we average over the number of samples as configured.
I just heard from John Wojnaroski that you and he are going to work on getting
a flightgear demo machine up for the linux expo thursday and Friday. John
indicated that he would very much like to get a CVS version with the new
traffic code up and running before the expo.
I've added some features to the PID controller:
Ability to set desired sampling interval in seconds. Use <Ts> under <config>
to set the desired sampling interval of the PID controller.
Example:
<config>
<Ts>0.1</Ts> <!-- desired sampling interval -->
<Kp>-0.05</Kp> <!-- proportional gain -->
<beta>1.0</beta> <!-- input value weighing factor -->
...
...
</config>
Ts defaults to 0.0, so if you don't set it it samples at the highest possible
frequency.
Add an offset to the input variables (input and reference).
Example:
<reference>
<prop>/controls/flight/elevator</prop>
<scale>-1.5</scale>
<offset>1.0</offset>
</reference>
Note that <scale> has higher precedence than <offset>, regardless of the order
that they appear in the config file.
a single apt.dat.gz file which is in the native X-Plane format.
To do this I wrote a front end loader than builds the airport and runway
list. Some of the changes I needed to make had a cascading effect, so there
are minor naming changes scattered throughout the code.
I've added some digital filters to the autopilot. They are all low-pass
filters that filter away high frequency signals/noise. There are 4 different
filters:
1. Exponential - The algorithm is essentially the same as the one used in the
fgGetLowPass() function.
2. Double exponential - Two exponential filters in series. This filter has a
"steeper" frequency response curve. It filters "better" than the single
exponential.
3. Moving average - Averages a number of inputs.
4. Noise spike - limits the amount that the output value can change from one
sample to the next.
Filters 1 and 2 are characterised by it's filter-time in seconds. For filter 3
you have to set the number of input samples to average over. For filter 4 you
set the maximum allowed rate of change as [1/s]. Since the sampling interval
(dt) isn't constant we have to calculate the maximum allowed change for every
update.
Example of a double exponential filter with filter time 0.1 seconds, that is
1/0.1 = 10 Hz.
<filter>
<name>pressure-rate-filter</name>
<debug>true</debug>
<type>double-exponential</type>
<input>/autopilot/internal/pressure-rate</input>
<output>/autopilot/internal/filtered-pressure-rate</output>
<filter-time>0.1</filter-time>
</filter>
This would go in the autopilot configuration file.
I've also removed the filtering of the "pressure-rate" helper value, use the
new filters if you want to filter it! ;-)
This patch adds the ability to do a simple scaling of input without having to
add hardcoded helpers. Example:
<reference>
<prop>/autopilot/settings/vertical-speed-fpm</prop>
<scale>0.01667</scale>
</reference>
Add FGPredictor class to xmlauto. Add support for horizontal navigation based
on flight track as opposed to heading. Add crosstrack-error support to nav.
Simplify error adjust calculation for horizontal nav (better interception).
Fixed potential divide by zero that was producing nan issues in the xmlauto
code.
I've done some changes to xmlauto.cxx.
Only calculate the derivate filtering if derivate time Td is greater than
zero. This means that one can set Td=0.0 in the xml file to completely remove
the derivate action. (Setting Td to zero in the current version would lead to
a division by zero and crash.)
Setting the integrator time Ti to zero doesn't make sense, right! I've
modified so that setting Ti to zero results in the integral action being
completely removed.
seem to be fully deterministic in P-only mode. This old simple controller
does what I expect, so it's good for calulating stage #1's of multi-stage
controllers.
controls in the cockpit vs. which wheels they apply to. FlightGear now
sets /controls/gear/brake-left, /controls/gear/brake-right, and
/controls/gear/brake-parking. It should be up to the FDM to sort out
which wheels under which circumstances are affected by these controls
and ultimately what happens to the physical motion of the aircraft.
This has been on my local copy for a while (well tested :-))
It fixes a problem with the auto throttle jumping around needlessly. Adjustments are calculated based on the last calculated autothrottle setting rather than reading the throttle setting from the property tree.
These changes should preserve previous functionality (with the exception of a
couple bug fixes).
Bugs fixed:
- AP no longer resets the error accumulator when switching altitude modes or
just closing the autopilot GUI. It will not be necessary to collect the barf
bags after selecting a new altitude anymore. Makes things much smoother.
- climb_rate calculation in the altitude hold mode included a factor that made
sense for the c172. It is now scaled according to the configuration's target
climb rate.
Additions:
Autothrottle (supports speed control only) is more configurable and accurate.
VerticalSpeed mode added (automatically arms to altitude if flown toward
altitude setting).
Exposed various properties, added new lock properties.
clarity:
nav_radial => nav_target_radial (same as selected, except for a LOC)
nav_heading => nav_reciprocal_radial
nav_magvar => nav_twist (it's not always the same as magvar)
nav_heading_needle_deflection => nav_cdi_deflection
nav_gs_needle_deflection => nav_gs_deflection
Added nav_radial back in, but now it shows the current radial from the
VOR, as one would expect. This value also appears in the
/radios/nav[*]/radials/actual-deg property.
scene management code and organizing it within simgear. My strategy is
to identify the code I want to move, and break it's direct flightgear
dependencies. Then it will be free to move over into the simgear package.
- Moved some property specific code into simgear/props/
- Split out the condition code from fgfs/src/Main/fg_props and put it
in it's own source file in simgear/props/
- Created a scene subdirectory for scenery, model, and material property
related code.
- Moved location.[ch]xx into simgear/scene/model/
- The location and condition code had dependencies on flightgear's global
state (all the globals-> stuff, the flightgear property tree, etc.) SimGear
code can't depend on it so that data has to be passed as parameters to the
functions/methods/constructors.
- This need to pass data as function parameters had a dramatic cascading
effect throughout the FlightGear code.
I modified the files in src/Autopilot to add waypoint capabilities to the telnet port.
'set waypoint <WPT>' will set the next waypoint.
'get waypoint' returns one string which is the list of waypoints.
'set waypoint 0' will delete the next waypoint.
The general idea is to help clean up some aspects of the FDM init and be
able to provide startup conditions in a less ambiguous manner.
Previously, things like positions, orientations, and velocites were set on
"the bus". These had to be read by the FDMs which then were supposed to
initialized themselves to those values and turn write around and start
modifying those values. It was messy and cumbersome.
Now, all the initial fdm conditions are written to a sub-[property-]tree
under /sim/presets/
The values in /sim/presets/ always stay set to what the user has specified.
The user can change these at his/her liesure, and then request a "reset"
which will reset to the new conditions. I don't even want to say how this
worked before. :-)
Now, an script, or gui interface can stage a set of initial conditions while
the sim is running (without disrupting it), and then call "reset" to commit
the change.
People who should worry about all this are FDM writters, and a small few
others who care about over all program structure and flow.
- Removed some old cruft.
- Removed some support for older versions of automake which technically was
correct, but caused the newer automakes to squawk warnings during an
initial sanity check (which isn't done very intelligently.)
NOTE: this fix is technically not correct for older version of automake.
These older version use the variable "INCLUDES" internally and could have
them already set to an important value. That is why we were appending
our values to them. However, newer versions of automake don't set this
value themselves so it is an error to append to a non-existant variable.
We seem to "get away" with overwriting the value on older versions of
automake, but if you have problems, consider upgrading to at least
automake-1.5.
This is a small patch that makes the autopilot work much better with big heavy
airliners as well as the small Cessnas. Of course this doesn't address the
way autopilots should be modeled.
But by making a couple changes the "George" is now capable of landing either a
C172 or a 747 very close to the center line of the runway with a moderate
cross breeze (15-20kt).
The changes:
- Added turn configurability so that things like Max Aileron and Roll can be
configured per aircraft.
- Enhanced localizer routine (NAV mode) to begin lining up the aircraft as soon
as the cone is entered. The former model is adopted for the last 5km of the
approach in order to ensure greater precision (makes a very slight difference).
[float cast added by David Megginson to keep G++ 3.0 happy]
This is a small patch that makes the autopilot work much better with big heavy
airliners as well as the small Cessnas. Of course this doesn't address the
way autopilots should be modeled.
But by making a couple changes the "George" is now capable of landing either a
C172 or a 747 very close to the center line of the runway with a moderate
cross breeze (15-20kt).
The changes:
- Added turn configurability so that things like Max Aileron and Roll can be
configured per aircraft.
- Enhanced localizer routine (NAV mode) to begin lining up the aircraft as soon
as the cone is entered. The former model is adopted for the last 5km of the
approach in order to ensure greater precision (makes a very slight difference).
[float cast added by David Megginson to keep G++ 3.0 happy]
- changed FGSubsystem::update(int) to
FGSubsystem::update(delta_time_sec); the argument is now delta time
in seconds rather than milliseconds
- added FGSubsystem::suspend(), FGSubsystem::suspend(bool),
FGSubsystem::resume(), and FGSubsystem::is_suspended(), all with
default implementations; is_suspended takes account of the master
freeze as well as the subsystem's individual suspended state
- the FDMs now use the delta time argument the same as the rest of
FlightGear; formerly, main.cxx made a special case and passed a
multiloop argument
- FDMs now calculate multiloop internally instead of relying on
main.cxx
There are probably some problems -- I've done basic testing with the
major FDMs and subsystems, but we'll probably need a few weeks to
sniff out bugs.
interface instead of string. This will result in a lot more
efficiency later, once I add in a simple hash table for caching
lookups, since it will avoid creating a lot of temporary string
objects. The major considerations for users will be that they cannot
use
node->getName() == "foo";
any more, and will have to use c_str() when setting a string value
from a C++ string.
separate header file. This change will help integrate properties into
JSBSim.
Also, I (David Megginson) removed most of the SimGear include
statements from globals.hxx, reducing the amount of recompilation
every time SimGear changes. This required making minor changes to a
lot of files that were depending on the side-effects of the inclusions
in globals.hxx.
- implement the standard FGSubsystem interface, for consistency
- eliminate current_autopilot and add get/set_autopilot to FGGlobals,
for consistency
- use private methods rather than static functions for tying
properties
There should be no change in functionality.
These changes add to the "Add Waypoint" dialog so that you can see the entire
list in the pui dialog that you are adding to. Also made some minor changes
so that the autopilot is now activated (toward first waypoint target heading)
when a waypoint is added.
newauto.cxx. Basically everything is the same functionally except for a
changed in the initial altitude setting to 3000ft instead of meters (the panel
is in feet).
the panel controls for the autopilot. The heading dialog would only show the
last setting you did through it, even if it was later tweaked with the bug on
the hsi. The altitude dialog did a similar thing. Now the values default to
the same that show on the panel displays.
- automake-1.4 sets default values for INCLUDES which we can't
overwrite.
- automake-1.5 renames this to DEFAULT_INCLUDES and leaves INCLUDES
open for the developer to use.
Thus for automake-1.4 we are forced to 'append' to INCLUDES and in
automake-1.5 we can just set the value to whatever we like.
Unfortunately, the behaviors of the two versions are mutually
incompatible.
The solution I am committing now works for both versions but
automake-1.5 generates a lot of spurious warning messages that are
annoying, but not fatal.
Here's an unusual patch for FlightGear -- I've created .cvsignore
files for every source directory, to make CVS output more informative.
This is especially nice when using cvs-examine from (X)Emacs to look
for changes.
fix startup sequence problems where we initialize the FDM before we know
the desired starting altitude.
These changes delay fdm initialization until the local tile has been loaded
and we can do a real intersection and find the true ground elevation.
In order to do this, I depend more on the property manager as glue, rather
than the FGInterface.
There are some glitches still when switching to a new airport or reseting
the sim. I will work on addressing these, but I need to commit the changes
so far to keep in sync with other developers.
Fixed a few glitches in the autopilot keys
Added a #define to be able to make a compile time decision to revert to
older GPS like autopiolt behavior this define SHOULD become a property
so that it is run time switchable.
DG heading bug initializes to a random setting.
Activating heading hold doesn't touch the DG heading bug any more.
Max autopilot decent rate is now -1000.
good as we can get" until we find a data source with actual VOR magnetic
offsets. We can use VOR offsets from some fixed date, but not all VOR's
were installed on the same day so no matter what date we pick we will be off on most of them.
FGOptions is history, and the modules are (starting) to use the property
manager directly. Let me know if I left any files out.
Inevitably, there will be some problems with broken options, etc.,
that I haven't found in my tests, but I'll try to fix them quickly.
We also need to stress that the property names currently in use are
not stable -- we need to reorganize them a bit for clarity.
