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JSBSim Flight Dynamics Model 1.2.2 (22 Mar 2025)
An Open Source Flight Dynamics and Control Software Library in C++
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Manages the external and/or arbitrary forces and moments.
The external reactions capability in JSBSim really should be named "arbitrary forces and moments", because this feature can be used to model a wide variety of forces and moments that act on a vehicle. Some examples include: parachutes, catapult, arresting hook, and tow line.
This class acts similarly to the other "manager classes" (FGPropulsion, FGFCS, FGGroundReactions, FGAerodynamics) because it manages collections of constituent elements. The individual forces and moments are implemented with the FGExternalForce class.
The format of the optional external reactions section in the config file is as follows:
See the FGExternalForce class for more information on the format of the force and moment specifications.
When force or moment elements are encountered in the configuration file, a new instance of the FGExternalForce class is created and a pointer to the class is pushed onto the Forces vector.
This class is one of a few of the manager classes that allows properties to be "declared". In code, these are represented by the interface_properties vector. Properties that have not yet been created in an already parsed section of the configuration file and that are used in the definition of an external force or moment should be declared in the external_reactions section because they will not be created automatically, and so would cause an error, since the property cannot be found to exist.
See the FGExternalForce documentation for details on how forces and moments are actually calculated.
Definition at line 121 of file FGExternalReactions.h.
#include <FGExternalReactions.h>
Public Member Functions | |
FGExternalReactions (FGFDMExec *fdmex) | |
Constructor. | |
~FGExternalReactions (void) override | |
Destructor. | |
double | GetForces (int idx) const |
const FGColumnVector3 & | GetForces (void) const |
Retrieves the total forces defined in the external reactions. | |
double | GetMoments (int idx) const |
const FGColumnVector3 & | GetMoments (void) const |
Retrieves the total moment resulting from the forces defined in the external reactions. | |
bool | InitModel (void) override |
bool | Load (Element *el) override |
Loads the external forces from the XML configuration file. | |
bool | Run (bool Holding) override |
Sum all the constituent forces for this cycle. | |
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FGModel (FGFDMExec *) | |
Constructor. | |
~FGModel () override | |
Destructor. | |
virtual SGPath | FindFullPathName (const SGPath &path) const |
FGFDMExec * | GetExec (void) |
const std::string & | GetName (void) |
unsigned int | GetRate (void) |
Get the output rate for the model in frames. | |
bool | InitModel (void) override |
void | SetPropertyManager (std::shared_ptr< FGPropertyManager > fgpm) |
void | SetRate (unsigned int tt) |
Set the ouput rate for the model in frames. | |
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std::string | GetFunctionStrings (const std::string &delimeter) const |
Gets the strings for the current set of functions. | |
std::string | GetFunctionValues (const std::string &delimeter) const |
Gets the function values. | |
std::shared_ptr< FGFunction > | GetPreFunction (const std::string &name) |
Get one of the "pre" function. | |
bool | Load (Element *el, FGFDMExec *fdmex, std::string prefix="") |
void | PostLoad (Element *el, FGFDMExec *fdmex, std::string prefix="") |
void | PreLoad (Element *el, FGFDMExec *fdmex, std::string prefix="") |
void | RunPostFunctions (void) |
void | RunPreFunctions (void) |
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FGJSBBase () | |
Constructor for FGJSBBase. | |
virtual | ~FGJSBBase () |
Destructor for FGJSBBase. | |
void | disableHighLighting (void) |
Disables highlighting in the console output. | |
Additional Inherited Members | |
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enum | { eL = 1 , eM , eN } |
Moments L, M, N. More... | |
enum | { eP = 1 , eQ , eR } |
Rates P, Q, R. More... | |
enum | { eU = 1 , eV , eW } |
Velocities U, V, W. More... | |
enum | { eX = 1 , eY , eZ } |
Positions X, Y, Z. More... | |
enum | { ePhi = 1 , eTht , ePsi } |
Euler angles Phi, Theta, Psi. More... | |
enum | { eDrag = 1 , eSide , eLift } |
Stability axis forces, Drag, Side force, Lift. More... | |
enum | { eRoll = 1 , ePitch , eYaw } |
Local frame orientation Roll, Pitch, Yaw. More... | |
enum | { eNorth = 1 , eEast , eDown } |
Local frame position North, East, Down. More... | |
enum | { eLat = 1 , eLong , eRad } |
Locations Radius, Latitude, Longitude. More... | |
enum | { inNone = 0 , inDegrees , inRadians , inMeters , inFeet } |
Conversion specifiers. More... | |
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static const std::string & | GetVersion (void) |
Returns the version number of JSBSim. | |
static constexpr double | KelvinToFahrenheit (double kelvin) |
Converts from degrees Kelvin to degrees Fahrenheit. | |
static constexpr double | CelsiusToRankine (double celsius) |
Converts from degrees Celsius to degrees Rankine. | |
static constexpr double | RankineToCelsius (double rankine) |
Converts from degrees Rankine to degrees Celsius. | |
static constexpr double | KelvinToRankine (double kelvin) |
Converts from degrees Kelvin to degrees Rankine. | |
static constexpr double | RankineToKelvin (double rankine) |
Converts from degrees Rankine to degrees Kelvin. | |
static constexpr double | FahrenheitToCelsius (double fahrenheit) |
Converts from degrees Fahrenheit to degrees Celsius. | |
static constexpr double | CelsiusToFahrenheit (double celsius) |
Converts from degrees Celsius to degrees Fahrenheit. | |
static constexpr double | CelsiusToKelvin (double celsius) |
Converts from degrees Celsius to degrees Kelvin. | |
static constexpr double | KelvinToCelsius (double kelvin) |
Converts from degrees Kelvin to degrees Celsius. | |
static constexpr double | FeetToMeters (double measure) |
Converts from feet to meters. | |
static bool | EqualToRoundoff (double a, double b) |
Finite precision comparison. | |
static bool | EqualToRoundoff (float a, float b) |
Finite precision comparison. | |
static bool | EqualToRoundoff (float a, double b) |
Finite precision comparison. | |
static bool | EqualToRoundoff (double a, float b) |
Finite precision comparison. | |
static constexpr double | Constrain (double min, double value, double max) |
Constrain a value between a minimum and a maximum value. | |
static constexpr double | sign (double num) |
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static char | highint [5] = {27, '[', '1', 'm', '\0' } |
highlights text | |
static char | halfint [5] = {27, '[', '2', 'm', '\0' } |
low intensity text | |
static char | normint [6] = {27, '[', '2', '2', 'm', '\0' } |
normal intensity text | |
static char | reset [5] = {27, '[', '0', 'm', '\0' } |
resets text properties | |
static char | underon [5] = {27, '[', '4', 'm', '\0' } |
underlines text | |
static char | underoff [6] = {27, '[', '2', '4', 'm', '\0' } |
underline off | |
static char | fgblue [6] = {27, '[', '3', '4', 'm', '\0' } |
blue text | |
static char | fgcyan [6] = {27, '[', '3', '6', 'm', '\0' } |
cyan text | |
static char | fgred [6] = {27, '[', '3', '1', 'm', '\0' } |
red text | |
static char | fggreen [6] = {27, '[', '3', '2', 'm', '\0' } |
green text | |
static char | fgdef [6] = {27, '[', '3', '9', 'm', '\0' } |
default text | |
static short | debug_lvl = 1 |
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bool | Upload (Element *el, bool preLoad) |
Uploads this model in memory. | |
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static std::string | CreateIndexedPropertyName (const std::string &Property, int index) |
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unsigned int | exe_ctr |
FGFDMExec * | FDMExec |
std::string | Name |
std::shared_ptr< FGPropertyManager > | PropertyManager |
unsigned int | rate |
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FGPropertyReader | LocalProperties |
std::vector< std::shared_ptr< FGFunction > > | PostFunctions |
std::vector< std::shared_ptr< FGFunction > > | PreFunctions |
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static constexpr double | radtodeg = 180. / M_PI |
static constexpr double | degtorad = M_PI / 180. |
static constexpr double | hptoftlbssec = 550.0 |
static constexpr double | psftoinhg = 0.014138 |
static constexpr double | psftopa = 47.88 |
static constexpr double | fttom = 0.3048 |
static constexpr double | ktstofps = 1852./(3600*fttom) |
static constexpr double | fpstokts = 1.0 / ktstofps |
static constexpr double | inchtoft = 1.0/12.0 |
static constexpr double | m3toft3 = 1.0/(fttom*fttom*fttom) |
static constexpr double | in3tom3 = inchtoft*inchtoft*inchtoft/m3toft3 |
static constexpr double | inhgtopa = 3386.38 |
static constexpr double | slugtolb = 32.174049 |
Note that definition of lbtoslug by the inverse of slugtolb and not to a different constant you can also get from some tables will make lbtoslug*slugtolb == 1 up to the magnitude of roundoff. | |
static constexpr double | lbtoslug = 1.0/slugtolb |
static constexpr double | kgtolb = 2.20462 |
static constexpr double | kgtoslug = 0.06852168 |
static const std::string | needed_cfg_version = "2.0" |
static const std::string | JSBSim_version = JSBSIM_VERSION " " __DATE__ " " __TIME__ |
FGExternalReactions | ( | FGFDMExec * | fdmex | ) |
Constructor.
fdmex | pointer to the main executive class. |
Definition at line 51 of file FGExternalReactions.cpp.
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override |
Destructor.
Within the destructor the Forces and interface_properties vectors are cleared out and the items pointed to are deleted.
Definition at line 93 of file FGExternalReactions.cpp.
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inline |
Definition at line 158 of file FGExternalReactions.h.
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inline |
Retrieves the total forces defined in the external reactions.
Definition at line 157 of file FGExternalReactions.h.
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inline |
Definition at line 164 of file FGExternalReactions.h.
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inline |
Retrieves the total moment resulting from the forces defined in the external reactions.
Definition at line 163 of file FGExternalReactions.h.
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overridevirtual |
Reimplemented from FGModelFunctions.
Definition at line 102 of file FGExternalReactions.cpp.
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overridevirtual |
Loads the external forces from the XML configuration file.
If the external_reactions section is encountered in the vehicle configuration file, this Load() method is called. All external forces will be parsed, and a FGExternalForce object will be instantiated for each force definition.
el | a pointer to the XML element holding the external reactions definition. |
Reimplemented from FGModel.
Definition at line 58 of file FGExternalReactions.cpp.
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overridevirtual |
Sum all the constituent forces for this cycle.
Can pass in a value indicating if the executive is directing the simulation to Hold.
Holding | if true, the executive has been directed to hold the sim from advancing time. Some models may ignore this flag, such as the Input model, which may need to be active to listen on a socket for the "Resume" command to be given. |
Reimplemented from FGModel.
Definition at line 114 of file FGExternalReactions.cpp.