/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
-
+
Header: FGTrim.h
Author: Tony Peden
Date started: 7/1/99
-
+
------------- Copyright (C) 1999 Anthony K. Peden (apeden@earthlink.net) -------------
-
+
This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.
-
+
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details.
-
+
You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA.
-
+
Further information about the GNU General Public License can also be found on
the world wide web at http://www.gnu.org.
-
-
+
+
HISTORY
--------------------------------------------------------------------------------
9/8/99 TP Created
-
-
+
+
FUNCTIONAL DESCRIPTION
--------------------------------------------------------------------------------
-
+
This class takes the given set of IC's and finds the aircraft state required to
-maintain a specified flight condition. This flight condition can be
+maintain a specified flight condition. This flight condition can be
steady-level with non-zero sideslip, a steady turn, a pull-up or pushover.
On-ground conditions can be trimmed as well, but this is currently limited to
adjusting altitude and pitch angle only. It is implemented using an iterative,
-one-axis-at-a-time scheme.
-
+one-axis-at-a-time scheme.
+
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
SENTRY
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
namespace JSBSim {
-typedef enum { tLongitudinal, tFull, tGround, tPullup,
- tCustom, tNone, tTurn
+typedef enum { tLongitudinal, tFull, tGround, tPullup,
+ tCustom, tNone, tTurn
} TrimMode;
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
the steady state described by the FGInitialCondition object . It does this
iteratively by assigning a control to each state and adjusting that control
until the state is within a specified tolerance of zero. States include the
- recti-linear accelerations udot, vdot, and wdot, the angular accelerations
+ recti-linear accelerations udot, vdot, and wdot, the angular accelerations
qdot, pdot, and rdot, and the difference between heading and ground track.
Controls include the usual flight deck controls available to the pilot plus
- angle of attack (alpha), sideslip angle(beta), flight path angle (gamma),
+ angle of attack (alpha), sideslip angle(beta), flight path angle (gamma),
pitch attitude(theta), roll attitude(phi), and altitude above ground. The
last three are used for on-ground trimming. The state-control pairs used in
a given trim are completely user configurable and several pre-defined modes
- tPullup: tLongitudinal but adjust alpha to achieve load factor input
with SetTargetNlf()
- tGround: wdot with altitude, qdot with theta, and pdot with phi
-
+
The remaining modes include <b>tCustom</b>, which is completely user defined and
<b>tNone</b>.
Note that trims can (and do) fail for reasons that are completely outside
- the control of the trimming routine itself. The most common problem is the
+ the control of the trimming routine itself. The most common problem is the
initial conditions: is the model capable of steady state flight
at those conditions? Check the speed, altitude, configuration (flaps,
gear, etc.), weight, cg, and anything else that may be relevant.
-
+
Example usage:<pre>
FGFDMExec* FDMExec = new FGFDMExec();
FGInitialCondition* fgic = new FGInitialCondition(FDMExec);
- FGTrim *fgt(FDMExec,fgic,tFull);
+ FGTrim fgt(FDMExec, fgic, tFull);
fgic->SetVcaibratedKtsIC(100);
fgic->SetAltitudeFtIC(1000);
fgic->SetClimbRate(500);
- if( !fgt->DoTrim() ) {
+ if( !fgt.DoTrim() ) {
cout << "Trim Failed" << endl;
}
- fgt->ReportState(); </pre>
+ fgt.Report(); </pre>
@author Tony Peden
@version "$Id$"
-*/
-
+*/
+
/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
CLASS DECLARATION
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
double xlo,xhi,alo,ahi;
double targetNlf;
int debug_axis;
-
+
double psidot,thetadot;
FGFDMExec* fdmex;
FGInitialCondition* fgic;
-
+
bool solve(void);
-
+
/** @return false if there is no change in the current axis accel
between accel(control_min) and accel(control_max). If there is a
change, sets solutionDomain to:
bool findInterval(void);
bool checkLimits(void);
-
+
void setupPullup(void);
void setupTurn(void);
-
+
void updateRates(void);
void setDebug(void);
*/
bool DoTrim(void);
- /** Print the results of the trim. For each axis trimmed, this
+ /** Print the results of the trim. For each axis trimmed, this
includes the final state value, control value, and tolerance
used.
@return true if trim succeeds
- */
+ */
void Report(void);
-
+
/** Iteration statistics
*/
void TrimStats();
-
+
/** Clear all state-control pairs and set a predefined trim mode
@param tm the set of axes to trim. Can be:
tLongitudinal, tFull, tGround, tCustom, or tNone
/** Clear all state-control pairs from the current configuration.
The trimming routine must have at least one state-control pair
configured to be useful
- */
+ */
void ClearStates(void);
/** Add a state-control pair to the current configuration. See the enums
State and Control in FGTrimAxis.h for the available options.
Will fail if the given state is already configured.
- @param state the accel or other condition to zero
+ @param state the accel or other condition to zero
@param control the control used to zero the state
@return true if add is successful
- */
+ */
bool AddState( State state, Control control );
-
+
/** Remove a specific state-control pair from the current configuration
@param state the state to remove
@return true if removal is successful
- */
+ */
bool RemoveState( State state );
-
+
/** Change the control used to zero a state previously configured
- @param state the accel or other condition to zero
+ @param state the accel or other condition to zero
@param new_control the control used to zero the state
*/
bool EditState( State state, Control new_control );
flight path angle (gamma) once it becomes apparent that there
is not enough/too much thrust.
@param bb true to enable fallback
- */
+ */
inline void SetGammaFallback(bool bb) { gamma_fallback=bb; }
-
+
/** query the fallback state
@return true if fallback is enabled.
*/
/** Set the iteration limit. DoTrim() will return false if limit
iterations are reached before trim is achieved. The default
is 60. This does not ordinarily need to be changed.
- @param ii integer iteration limit
+ @param ii integer iteration limit
*/
inline void SetMaxCycles(int ii) { max_iterations = ii; }
-
+
/** Set the per-axis iteration limit. Attempt to zero each state
by iterating limit times before moving on to the next. The
default limit is 100 and also does not ordinarily need to
be changed.
- @param ii integer iteration limit
- */
+ @param ii integer iteration limit
+ */
inline void SetMaxCyclesPerAxis(int ii) { max_sub_iterations = ii; }
-
+
/** Set the tolerance for declaring a state trimmed. Angular accels are
- held to a tolerance of 1/10th of the given. The default is
+ held to a tolerance of 1/10th of the given. The default is
0.001 for the recti-linear accelerations and 0.0001 for the angular.
- */
+ */
inline void SetTolerance(double tt) {
Tolerance = tt;
A_Tolerance = tt / 10;
}
-
- /**
+
+ /**
Debug level 1 shows results of each top-level iteration
Debug level 2 shows level 1 & results of each per-axis iteration
- */
+ */
inline void SetDebug(int level) { DebugLevel = level; }
inline void ClearDebug(void) { DebugLevel = 0; }
-
+
/**
Output debug data for one of the axes
The State enum is defined in FGTrimAxis.h
- */
+ */
inline void DebugState(State state) { debug_axis=state; }
-
+
inline void SetTargetNlf(float nlf) { targetNlf=nlf; }
inline double GetTargetNlf(void) { return targetNlf; }