-/*******************************************************************************
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Header: FGTrim.h
Author: Tony Peden
conditions only. It is implemented using an iterative, one-axis-at-a-time
scheme.
-
-
-********************************************************************************
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
SENTRY
-*******************************************************************************/
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#ifndef FGTRIM_H
#define FGTRIM_H
-/*******************************************************************************
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
INCLUDES
-*******************************************************************************/
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
#include "FGFDMExec.h"
#include "FGRotation.h"
#include "FGTrim.h"
#include "FGTrimAxis.h"
-#include <vector.h>
+#include <vector>
-#define ID_TRIM "$Header"
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+DEFINITIONS
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-/*******************************************************************************
-CLASS DECLARATION
-*******************************************************************************/
+#define ID_TRIM "$Id$"
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+FORWARD DECLARATIONS
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
-typedef enum { tLongitudinal, tFull, tGround } TrimMode;
+typedef enum { tLongitudinal, tFull, tGround, tCustom, tNone } TrimMode;
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+COMMENTS, REFERENCES, and NOTES [use "class documentation" below for API docs]
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+CLASS DOCUMENTATION
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
+
+/** FGTrim -- the trimming routine for JSBSim.
+ FGTrim finds the aircraft attitude and control settings needed to maintain
+ 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
+ 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),
+ 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
+ are provided as well. They are:
+ <ul>
+ <li> tLongitudinal: Trim wdot with alpha, udot with thrust, qdot with elevator</li>
+ <li> tFull: tLongitudinal + vdot with phi, pdot with aileron, rdot with rudder
+ and heading minus ground track (hmgt) with beta</li>
+ <li> tGround: wdot with altitude, qdot with theta, and pdot with phi</li>
+ The remaining modes include <b>tCustom</b>, which is completely user defined and
+ <b>tNone</b>.
+ </ul>
+ Currently, this class cannot trim a non-1g condition and is limited to
+ trimming for constant true airspeed in climbs and descents.
+
+ 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
+ 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:
+ FGFDMExec* FDMExec = new FGFDMExec();
+ .
+ .
+ .
+ FGInitialCondition* fgic = new FGInitialCondition(FDMExec);
+ FGTrim *fgt(FDMExec,fgic,tFull);
+ fgic->SetVcaibratedKtsIC(100);
+ fgic->SetAltitudeFtIC(1000);
+ fgic->SetClimbRate(500);
+ if( !fgt->DoTrim() ) {
+ cout << "Trim Failed" << endl;
+ }
+ fgt->ReportState();
+ @author Tony Peden
+ @version $Id$
+*/
+
+/*%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+CLASS DECLARATION
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%*/
class FGTrim {
private:
vector<FGTrimAxis*> TrimAxes;
int current_axis;
int N, Nsub;
- int NumAxes;
TrimMode mode;
int Debug;
float Tolerance, A_Tolerance;
int solutionDomain;
float xlo,xhi,alo,ahi;
-
FGFDMExec* fdmex;
FGInitialCondition* fgic;
-
- // returns 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:
- // 0 for no sign change,
- // -1 if sign change between accel(control_min) and accel(0)
- // 1 if sign between accel(0) and accel(control_max)
+
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:
+ 0 for no sign change,
+ -1 if sign change between accel(control_min) and accel(0)
+ 1 if sign between accel(0) and accel(control_max)
+ */
bool findInterval(void);
+
bool checkLimits(void);
public:
+ /** Initializes the trimming class
+ @param FDMExec pointer to a JSBSim executive object.
+ @param FGIC pointer to a FGInitialCondition object
+ @param TrimMode the set of axes to trim. Can be:
+ tLongitudinal, tFull, tGround, tCustom, or tNone
+ */
FGTrim(FGFDMExec *FDMExec, FGInitialCondition *FGIC, TrimMode tt);
- ~FGTrim(void);
+ ~FGTrim(void);
+
+ /** Execute the trim
+ */
bool DoTrim(void);
+ /** 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);
+
+ /** Prints a summary of simulator state (speed, altitude,
+ configuration, etc.)
+ */
void ReportState(void);
+
+ /** Iteration statistics
+ */
void TrimStats();
- inline void SetUdotTrim(bool bb) { trimudot=bb; }
- inline bool GetUdotTrim(void) { return trimudot; }
+ /** 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 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 control the control used to zero the state
+ */
+ bool EditState( State state, Control new_control );
+ /** automatically switch to trimming longitudinal acceleration with
+ flight path angle (gamma) once it becomes apparent that there
+ is not enough/too much thrust.
+ @param gamma_fallback true to enable fallback
+ */
inline void SetGammaFallback(bool bb) { gamma_fallback=true; }
+
+ /** query the fallback state
+ @return true if fallback is enabled.
+ */
inline bool GetGammaFallback(void) { return gamma_fallback; }
+ /** 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
+ */
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
+ */
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
+ 0.001 for the recti-linear accelerations and 0.0001 for the angular.
+ */
inline void SetTolerance(float 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) { Debug = level; }
projects / flightgear.git / blobdiff