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.
Here's a new FGSimTurbine module. Changes are:
1. Adds starting and stopping functionality
2. Calculate() now calls other functions, based on the engine's state, which gives more readable code.
Until now turbine engines were always running as long as fuel was available. With this new module the engine defaults to OFF. To start with the engine running, the variable FGEngine::Running must be set to true at sim startup. In FlightGear this is done with --prop:/engines/engine[n]/running=true.
To start the engine (on the ground), first set the starter to ON, i.e. FGEngine::Starter is set to true. In FlightGear this is done by toggling /controls/engines/engine[n]/starter to TRUE. Note that the current FlightGear key binding will not work, as it causes the starter to quit when the key is released. A new key binding is needed, without the mod-up.
When N2 reaches 15% or greater, place the fuel cutoff control to FALSE. This is FGEngine::Cutoff. In FlightGear this is done with /controls/engines/engine[n]/cutoff set to FALSE. The engine will then accelerate to idle. Upon reaching idle, the starter is automatically turned off, and the engine is running. There is presently no FlightGear key binding for the fuel cutoff switch.
To shut off the engine, place the fuel cutoff control to TRUE.
If you shut down the engine in flight it will windmill. To airstart you will need at least 15% N2, just as with a ground start. When you have enough N2, place the cutoff control to FALSE and the engine will restart. Note that if you can't get enough N2 by speeding up, you can get it by using the starter.
The reverser still works, and is controlled in FlightGear with /controls/engines/engine[n]/reverser. With the reverser control on (TRUE), the engine will produce negative thrust in proportion to throttle position, i.e. to get more reverse
thrust, increase throttle.
Here's a new FGSimTurbine module. Changes are:
1. Adds starting and stopping functionality
2. Calculate() now calls other functions, based on the engine's state, which gives more readable code.
Until now turbine engines were always running as long as fuel was available. With this new module the engine defaults to OFF. To start with the engine running, the variable FGEngine::Running must be set to true at sim startup. In FlightGear this is done with --prop:/engines/engine[n]/running=true.
To start the engine (on the ground), first set the starter to ON, i.e. FGEngine::Starter is set to true. In FlightGear this is done by toggling /controls/engines/engine[n]/starter to TRUE. Note that the current FlightGear key binding will not work, as it causes the starter to quit when the key is released. A new key binding is needed, without the mod-up.
When N2 reaches 15% or greater, place the fuel cutoff control to FALSE. This is FGEngine::Cutoff. In FlightGear this is done with /controls/engines/engine[n]/cutoff set to FALSE. The engine will then accelerate to idle. Upon reaching idle, the starter is automatically turned off, and the engine is running. There is presently no FlightGear key binding for the fuel cutoff switch.
To shut off the engine, place the fuel cutoff control to TRUE.
If you shut down the engine in flight it will windmill. To airstart you will need at least 15% N2, just as with a ground start. When you have enough N2, place the cutoff control to FALSE and the engine will restart. Note that if you can't get enough N2 by speeding up, you can get it by using the starter.
The reverser still works, and is controlled in FlightGear with /controls/engines/engine[n]/reverser. With the reverser control on (TRUE), the engine will produce negative thrust in proportion to throttle position, i.e. to get more reverse thrust, increase throttle.
Square the normalized direction acceleration for the y and z axes, so
that turbulence predominantly affects pitch.
Bind to the /environment/turbulence/magnitude-norm and
/environment/turbulence/rate-hz properties in FlightGear.
This version handles a zero fuel load better. I found that if you try to consume fuel from an empty tank, with zero fuel flow, the FGEngine::Starved flag alternates
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.
ttStandard is copied from ttBerndt, with the following modifications:
1. All turbulence is diminished within three wingspans of the ground.
2. The horizontal forces are used to calculate the moments, but then
zeroed out so that only the vertical force is actually applied to
the aircraft.
3. The yaw moment is not used.
In fact, the horizontal forces and the yaw moment should be allowed,
but they are extremely rare compared to the vertical force and the
pitch/roll moments. For now, simply zeroing them gives the most
accurate feel.
Some more cmall changes to the SimGear header files and removed the
SG_HAVE_NATIVE_SGI_COMPILERS dependancies from FlightGear.
I've added a seperate JSBSim patch for the JSBSim source tree.
Changed steering to use the rudder command rather than the rudder
position. During taxi, the rudder trim shouldn't affect the steering
in any serious way.
This should be configurable in the aircraft file, since not all
aircraft use the rudder pedals for ground steering.
[In FlightGear, this may make it easier to taxi straight.]
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 new improved patch for the previous tile manager fixes.
Rather than building dependencies between FGlocation or the viewer or fdm with
tilemgr what I ended up doing was linking the pieces together in the Mainloop
in main.cxx. You'll see what I mean...it's been commented fairly well. More
than likely we should move that chunk somewhere...just not sure where yet.
The changes seem clean now. As I get more ideas there could be some further
improvement in organizing the update in tilemgr. You'll note that I left an
override in there for the tilemgr::update() function to preserve earlier
functionality if someone needs it (e.g. usage independent of an fdm or
viewer), not to mention there are a few places in flightgear that call it
directly that have not been changed to the new interface (and may not need to be).
The code has been optimized to avoid duplicate traversals and seems to run
generally quite well. Note that there can be a short delay reloading tiles
that have been dropped from static views. We could call the tile scheduler on
a view switch, but it's not a big deal and at the moment I'd like to get this
in so people can try it and comment on it as it is.
Everything has been resycned with CVS tonight and I've included the
description submitted earlier (below).
Best,
Jim
Changes synced with CVS approx 20:30EDT 2002-05-09 (after this evenings updates).
Files:
http://www.spiderbark.com/fgfs/viewer-update-20020516.tar.gz
or
http://www.spiderbark.com/fgfs/viewer-update-20020516.diffs.gz
Description:
In a nutshell, these patches begin to take what was one value for ground
elevation and calculate ground elevation values seperately for the FDM and the
viewer (eye position). Several outstanding view related bugs have been fixed.
With the introduction of the new viewer code a lot of that Flight Gear code
broke related to use of a global variable called "scenery.cur_elev".
Therefore the ground_elevation and other associated items (like the current
tile bucket) is maintained per FDM instance and per View. Each of these has a
"point" or location that can be identified. See changes to FGLocation class
and main.cxx.
Most of the problems related to the new viewer in terms of sky, ground and
runway lights, and tower views are fixed.
There are four minor problems remaining. 1) The sun/moon spins when you pan
the "lookat" tower view only (view #3). 2) Under stress (esp. magic carpet
full speed with max visibility), there is a memory leak in the tile caching
that was not introduced with these changes. 3) I have not tested these
changes or made corrections to the ADA or External FDM interfaces. 4) The
change view function doesn't call the time/light update (not a problem unless
a tower is very far away).
Details:
FDM/flight.cxx, flight.hxx - FGInterface ties to FGAircraftModel so that it's
location data can be accessed for runway (ground elevation under aircraft)
elevation.
FDM/larsim.cxx, larcsim.hxx - gets runway elevation from FGInterface now.
Commented out function that is causing a namespace conflict, hasn't been
called with recent code anyway.
FDM/JSBSim/JSBSim.cxx, YASim/YASim.cxx - gets runway elevation from
FGInterface now.
Scenery/newcache.cxx, newcache.hxx - changed caching scheme to time based
(oldest tiles discard).
Scenery/tileentry.cxx, tileentry.hxx - added place to record time, changed
rendering to reference viewer altitude in order to fix a problem with ground
and runway lights.
Scenery/tilemgr.cxx, tilemgr.hxx - Modified update() to accept values for
multiple locations. Refresh function added in order to periodically make
the tiles current for a non-moving view (like a tower).
Main/fg_init.cxx - register event for making tiles current in a non-moving
view (like a tower).
Main/location.hxx - added support for current ground elevation data.
Main/main.cxx - added second tilemgr call for fdm, fixed places where viewer
position data was required for correct sky rendering.
Main/options.cxx - fixed segfault reported by Curtis when using --view-offset
command line parameter.
Main/viewer.cxx, viewer.hxx - removed fudging of view position. Fixed numerous
bugs that were causing eye and target values to get mixed up.
set_Density; since JSBSim doesn't override the get_* methods from
FGInterface as well, the wrong values are always set anyway.
Take the static temperature, static pressure, and density values from
an external source if requested by the
/environment/params/control-fdm-atmosphere property. This isn't
working properly yet for JSBSim because of interactions with the
trimming routine.
- 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.
Changed the steering gain from +/-0.1 to +/-1.0, so that the steering
angle for the nosewheel (when present) is the same as the rudder
deflection angle. That's probably not exactly right, but it's much
better than we had before -- you can now steer the plane on the ground
reasonably during taxiing.
Attached is a fix to add a short period of cranking time required
before the engine fires. I've also added a little hack to limit the
torque applied by the starter motor when the rpm is less than 10 in
order to avoid the rpm overshooting idle in the first time step when
the prop is producing very little resistance due to the low rpm.
I've attached 3 diffs against files in FlightGear to fix some printf
format strings. The changes are pretty straight forward. Let me know
if you have any questions. (BTW, I'm using gcc 2.95.4)
otherwise, the logic in FGEngine::ConsumeFuel breaks down and the
engine is starved when *any* feed tank is empty, rather than when all
feed tanks are empty.
- 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.
(i.e. multiloop). Most subsystems currently ignore the parameter, but
eventually, it will allow all subsystems to update by time rather than
by framerate.
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.
LaRCsim c172 on-ground and in-air starts, reset: all work
UIUC Cessna172 on-ground and in-air starts work as expected, reset
results in an aircraft that is upside down but does not crash FG. I
don't know what it was like before, so it may well be no change.
JSBSim c172 and X15 in-air starts work fine, resets now work (and are
trimmed), on-ground starts do not -- the c172 ends up on its back. I
suspect this is no worse than before.
I did not test:
Balloon (the weather code returns nan's for the atmosphere data --this
is in the weather module and apparently is a linux only bug)
ADA (don't know how)
MagicCarpet (needs work yet)
External (don't know how)
known to be broken:
LaRCsim c172 on-ground starts with a negative terrain altitude (this
happens at KPAO when the scenery is not present). The FDM inits to
about 50 feet AGL and the model falls to the ground. It does stay
upright, however, and seems to be fine once it settles out, FWIW.
To do:
--implement set_Model on the bus
--bring Christian's weather data into JSBSim
-- add default method to bus for updating things like the sin and cos of
latitude (for Balloon, MagicCarpet)
-- lots of cleanup
The files:
src/FDM/flight.cxx
src/FDM/flight.hxx
-- all data members now declared protected instead of private.
-- eliminated all but a small set of 'setters', no change to getters.
-- that small set is declared virtual, the default implementation
provided preserves the old behavior
-- all of the vector data members are now initialized.
-- added busdump() method -- FG_LOG's all the bus data when called,
useful for diagnostics.
src/FDM/ADA.cxx
-- bus data members now directly assigned to
src/FDM/Balloon.cxx
-- bus data members now directly assigned to
-- changed V_equiv_kts to V_calibrated_kts
src/FDM/JSBSim.cxx
src/FDM/JSBSim.hxx
-- bus data members now directly assigned to
-- implemented the FGInterface virtual setters with JSBSim specific
logic
-- changed the static FDMExec to a dynamic fdmex (needed so that the
JSBSim object can be deleted when a model change is called for)
-- implemented constructor and destructor, moved some of the logic
formerly in init() to constructor
-- added logic to bring up FGEngInterface objects and set the RPM and
throttle values.
src/FDM/LaRCsim.cxx
src/FDM/LaRCsim.hxx
-- bus data members now directly assigned to
-- implemented the FGInterface virtual setters with LaRCsim specific
logic, uses LaRCsimIC
-- implemented constructor and destructor, moved some of the logic
formerly in init() to constructor
-- moved default inertias to here from fg_init.cxx
-- eliminated the climb rate calculation. The equivalent, climb_rate =
-1*vdown, is now in copy_from_LaRCsim().
src/FDM/LaRCsimIC.cxx
src/FDM/LaRCsimIC.hxx
-- similar to FGInitialCondition, this class has all the logic needed to
turn data like Vc and Mach into the more fundamental quantities LaRCsim
needs to initialize.
-- put it in src/FDM since it is a class
src/FDM/MagicCarpet.cxx
-- bus data members now directly assigned to
src/FDM/Makefile.am
-- adds LaRCsimIC.hxx and cxx
src/FDM/JSBSim/FGAtmosphere.h
src/FDM/JSBSim/FGDefs.h
src/FDM/JSBSim/FGInitialCondition.cpp
src/FDM/JSBSim/FGInitialCondition.h
src/FDM/JSBSim/JSBSim.cpp
-- changes to accomodate the new bus
src/FDM/LaRCsim/atmos_62.h
src/FDM/LaRCsim/ls_geodesy.h
-- surrounded prototypes with #ifdef __cplusplus ... #endif , functions
here are needed in LaRCsimIC
src/FDM/LaRCsim/c172_main.c
src/FDM/LaRCsim/cherokee_aero.c
src/FDM/LaRCsim/ls_aux.c
src/FDM/LaRCsim/ls_constants.h
src/FDM/LaRCsim/ls_geodesy.c
src/FDM/LaRCsim/ls_geodesy.h
src/FDM/LaRCsim/ls_step.c
src/FDM/UIUCModel/uiuc_betaprobe.cpp
-- changed PI to LS_PI, eliminates preprocessor naming conflict with
weather module
src/FDM/LaRCsim/ls_interface.c
src/FDM/LaRCsim/ls_interface.h
-- added function ls_set_model_dt()
src/Main/bfi.cxx
-- eliminated calls that set the NED speeds to body components. They
are no longer needed and confuse the new bus.
src/Main/fg_init.cxx
-- eliminated calls that just brought the bus data up-to-date (e.g.
set_sin_cos_latitude). or set default values. The bus now handles the
defaults and updates itself when the setters are called (for LaRCsim and
JSBSim). A default method for doing this needs to be added to the bus.
-- added fgVelocityInit() to set the speed the user asked for. Both
JSBSim and LaRCsim can now be initialized using any of:
vc,mach, NED components, UVW components.
src/Main/main.cxx
--eliminated call to fgFDMSetGroundElevation, this data is now 'pulled'
onto the bus every update()
src/Main/options.cxx
src/Main/options.hxx
-- added enum to keep track of the speed requested by the user
-- eliminated calls to set NED velocity properties to body speeds, they
are no longer needed.
-- added options for the NED components.
src/Network/garmin.cxx
src/Network/nmea.cxx
--eliminated calls that just brought the bus data up-to-date (e.g.
set_sin_cos_latitude). The bus now updates itself when the setters are
called (for LaRCsim and JSBSim). A default method for doing this needs
to be added to the bus.
-- changed set_V_equiv_kts to set_V_calibrated_kts. set_V_equiv_kts no
longer exists ( get_V_equiv_kts still does, though)
src/WeatherCM/FGLocalWeatherDatabase.cpp
-- commented out the code to put the weather data on the bus, a
different scheme for this is needed.
Tony submitted:
JSBsim:
Added trimming routine, it is longitudinal & in-air only at this point
Added support for taking wind & weather data from external source
Added support for flaps.
Added independently settable pitch trim
Added alphamin and max to config file, stall modeling and warning to
follow
c172.cfg:
Flaps!
Adjusted Cmo, model should be speed stable now
FG:
Hooked up Christian's weather code, should be using it soon.
Hooked up the trimming routine. Note that the X-15 will not trim.
This is not a model or trimming routine deficiency, just the
nature of the X-15
The trimming routine sets the pitch trim and and throttle at startup.
The throttle is set using Norman's code for the autothrottle so the
autothrottle is on by default. --notrim will turn it off.
Added --vc, --mach, and --notrim switches
(vc is airspeed in knots)
uBody, vBody, and wBody are still supported, last one entered
on the command line counts, i.e. you can set vc or mach or u,v,
and w but any combination will be ignored.
much less so due to returning the aero reference point stuff to the config
files. Don't know what happened there ...
Additionally, I have added a new field to the config file: CFG_VERSION. A
version number, currently 1.1, is assigned to the config file and a matching
definition is found in FGDefs.h. The two need to match. Tony has also added
code into FGAircraft.cpp to handle if aero reference point is not specified.
