How to declare Initial Conditions

[BadboyIntheLoop]

Hello All JSBsim members,

This Post I wanna discuss about Initial Conditions (IC), how to declare them in script file and tag effect happenings when running! If you know, please explain for me with filed tags about:

1. Environment: Atmosphere, Temperature, Winds (normal winds, turbulents, downburst, gust, ... ). What tag I need to declare with them.
2. FG function: FG_RAMP, FG_STEP ... How it run?
3. States like Position, orientation and velecity, angular velecity are OK! I think we all know!!!

I know it seem to be HUGE but we can make it sense!!!

[seanmcleod]

I'd suggest you first take a look at the JSBSim Reference Manual

[agodemar]

Or else have a look at this online reference manual.

[BadboyIntheLoop]

Yep, i've read manual as soon as I approach JSBsim but it's not enough to me to declare more conditions. For instance, I know JSBsim can simulate the winds like normal wind, guts and turbulent... but I dont know what the xml tag would be used. I wanna discuss that in here!!!

[BadboyIntheLoop]

jsbsim/examples/FlightGear.cxx

Lines 339 to 350 in 6461c86

	altitude = fgGetNode("/position/altitude-ft");
	temperature = fgGetNode("/environment/temperature-degc",true);
	pressure = fgGetNode("/environment/pressure-inhg",true);
	pressureSL = fgGetNode("/environment/pressure-sea-level-inhg",true);
	ground_wind = fgGetNode("/environment/config/boundary/entry[0]/wind-speed-kt",true);
	turbulence_gain = fgGetNode("/environment/turbulence/magnitude-norm",true);
	turbulence_rate = fgGetNode("/environment/turbulence/rate-hz",true);
	turbulence_model = fgGetNode("/environment/params/jsbsim-turbulence-model",true);
	wind_from_north= fgGetNode("/environment/wind-from-north-fps",true);
	wind_from_east = fgGetNode("/environment/wind-from-east-fps" ,true);
	wind_from_down = fgGetNode("/environment/wind-from-down-fps" ,true);

Dear all, please help me show the xml file that has the tags like that!!! Thank you so much

[seanmcleod]

Example of defining a gust in the source code documentation.

jsbsim/src/models/atmosphere/FGWinds.h

Lines 107 to 121 in 375f5be

	~~~{.xml}
	<event name="Introduce gust">
	<condition> simulation/sim-time-sec ge 10 </condition>
	<set name="atmosphere/cosine-gust/startup-duration-sec" value="5"/>
	<set name="atmosphere/cosine-gust/steady-duration-sec" value="1"/>
	<set name="atmosphere/cosine-gust/end-duration-sec" value="5"/>
	<set name="atmosphere/cosine-gust/magnitude-ft_sec" value="30"/>
	<set name="atmosphere/cosine-gust/frame" value="2"/>
	<set name="atmosphere/cosine-gust/X-velocity-ft_sec" value="-1"/>
	<set name="atmosphere/cosine-gust/Y-velocity-ft_sec" value="0"/>
	<set name="atmosphere/cosine-gust/Z-velocity-ft_sec" value="0"/>
	<set name="atmosphere/cosine-gust/start" value="1"/>
	<notify/>
	</event>
	~~~

And the complete set of properties available for wind.

jsbsim/src/models/atmosphere/FGWinds.cpp

Lines 488 to 564 in 375f5be

	void FGWinds::bind(void)
	{
	typedef double (FGWinds::*PMF)(int) const;
	typedef int (FGWinds::*PMFt)(void) const;
	typedef void (FGWinds::*PMFd)(int,double);
	typedef void (FGWinds::*PMFi)(int);
	typedef double (FGWinds::*Ptr)(void) const;
	// User-specified steady, constant, wind properties (local navigational/geographic frame: N-E-D)
	PropertyManager->Tie("atmosphere/psiw-rad", this, &FGWinds::GetWindPsi, &FGWinds::SetWindPsi);
	PropertyManager->Tie("atmosphere/wind-north-fps", this, eNorth, (PMF)&FGWinds::GetWindNED,
	(PMFd)&FGWinds::SetWindNED);
	PropertyManager->Tie("atmosphere/wind-east-fps", this, eEast, (PMF)&FGWinds::GetWindNED,
	(PMFd)&FGWinds::SetWindNED);
	PropertyManager->Tie("atmosphere/wind-down-fps", this, eDown, (PMF)&FGWinds::GetWindNED,
	(PMFd)&FGWinds::SetWindNED);
	PropertyManager->Tie("atmosphere/wind-mag-fps", this, &FGWinds::GetWindspeed,
	&FGWinds::SetWindspeed);
	// User-specifieded gust (local navigational/geographic frame: N-E-D)
	PropertyManager->Tie("atmosphere/gust-north-fps", this, eNorth, (PMF)&FGWinds::GetGustNED,
	(PMFd)&FGWinds::SetGustNED);
	PropertyManager->Tie("atmosphere/gust-east-fps", this, eEast, (PMF)&FGWinds::GetGustNED,
	(PMFd)&FGWinds::SetGustNED);
	PropertyManager->Tie("atmosphere/gust-down-fps", this, eDown, (PMF)&FGWinds::GetGustNED,
	(PMFd)&FGWinds::SetGustNED);
	// User-specified 1 - cosine gust parameters (in specified frame)
	PropertyManager->Tie("atmosphere/cosine-gust/startup-duration-sec", this, (Ptr)0L, &FGWinds::StartupGustDuration);
	PropertyManager->Tie("atmosphere/cosine-gust/steady-duration-sec", this, (Ptr)0L, &FGWinds::SteadyGustDuration);
	PropertyManager->Tie("atmosphere/cosine-gust/end-duration-sec", this, (Ptr)0L, &FGWinds::EndGustDuration);
	PropertyManager->Tie("atmosphere/cosine-gust/magnitude-ft_sec", this, (Ptr)0L, &FGWinds::GustMagnitude);
	PropertyManager->Tie("atmosphere/cosine-gust/frame", this, (PMFt)0L, (PMFi)&FGWinds::GustFrame);
	PropertyManager->Tie("atmosphere/cosine-gust/X-velocity-ft_sec", this, (Ptr)0L, &FGWinds::GustXComponent);
	PropertyManager->Tie("atmosphere/cosine-gust/Y-velocity-ft_sec", this, (Ptr)0L, &FGWinds::GustYComponent);
	PropertyManager->Tie("atmosphere/cosine-gust/Z-velocity-ft_sec", this, (Ptr)0L, &FGWinds::GustZComponent);
	PropertyManager->Tie("atmosphere/cosine-gust/start", this, static_cast<bool (FGWinds::*)(void) const>(nullptr), &FGWinds::StartGust);
	// User-specified Up- Down-burst parameters
	PropertyManager->Tie("atmosphere/updownburst/number-of-cells", this, (PMFt)0L, &FGWinds::NumberOfUpDownburstCells);
	// PropertyManager->Tie("atmosphere/updownburst/", this, (Ptr)0L, &FGWinds::);
	// PropertyManager->Tie("atmosphere/updownburst/", this, (Ptr)0L, &FGWinds::);
	// PropertyManager->Tie("atmosphere/updownburst/", this, (Ptr)0L, &FGWinds::);
	// PropertyManager->Tie("atmosphere/updownburst/", this, (Ptr)0L, &FGWinds::);
	// PropertyManager->Tie("atmosphere/updownburst/", this, (Ptr)0L, &FGWinds::);
	// PropertyManager->Tie("atmosphere/updownburst/", this, (Ptr)0L, &FGWinds::);
	// PropertyManager->Tie("atmosphere/updownburst/", this, (Ptr)0L, &FGWinds::);
	// User-specified turbulence (local navigational/geographic frame: N-E-D)
	PropertyManager->Tie("atmosphere/turb-north-fps", this, eNorth, (PMF)&FGWinds::GetTurbNED,
	(PMFd)&FGWinds::SetTurbNED);
	PropertyManager->Tie("atmosphere/turb-east-fps", this, eEast, (PMF)&FGWinds::GetTurbNED,
	(PMFd)&FGWinds::SetTurbNED);
	PropertyManager->Tie("atmosphere/turb-down-fps", this, eDown, (PMF)&FGWinds::GetTurbNED,
	(PMFd)&FGWinds::SetTurbNED);
	// Experimental turbulence parameters
	PropertyManager->Tie("atmosphere/p-turb-rad_sec", this,1, (PMF)&FGWinds::GetTurbPQR);
	PropertyManager->Tie("atmosphere/q-turb-rad_sec", this,2, (PMF)&FGWinds::GetTurbPQR);
	PropertyManager->Tie("atmosphere/r-turb-rad_sec", this,3, (PMF)&FGWinds::GetTurbPQR);
	PropertyManager->Tie("atmosphere/turb-type", this, (PMFt)&FGWinds::GetTurbType, (PMFi)&FGWinds::SetTurbType);
	PropertyManager->Tie("atmosphere/turb-rate", this, &FGWinds::GetTurbRate, &FGWinds::SetTurbRate);
	PropertyManager->Tie("atmosphere/turb-gain", this, &FGWinds::GetTurbGain, &FGWinds::SetTurbGain);
	PropertyManager->Tie("atmosphere/turb-rhythmicity", this, &FGWinds::GetRhythmicity,
	&FGWinds::SetRhythmicity);
	// Parameters for milspec turbulence
	PropertyManager->Tie("atmosphere/turbulence/milspec/windspeed_at_20ft_AGL-fps",
	this, &FGWinds::GetWindspeed20ft,
	&FGWinds::SetWindspeed20ft);
	PropertyManager->Tie("atmosphere/turbulence/milspec/severity",
	this, &FGWinds::GetProbabilityOfExceedence,
	&FGWinds::SetProbabilityOfExceedence);
	// Total, calculated winds (local navigational/geographic frame: N-E-D). Read only.
	PropertyManager->Tie("atmosphere/total-wind-north-fps", this, eNorth, (PMF)&FGWinds::GetTotalWindNED);
	PropertyManager->Tie("atmosphere/total-wind-east-fps", this, eEast, (PMF)&FGWinds::GetTotalWindNED);
	PropertyManager->Tie("atmosphere/total-wind-down-fps", this, eDown, (PMF)&FGWinds::GetTotalWindNED);