[Jsbsim-cvslogs] CVS: JSBSim/src/models FGLGear.cpp, 1.50, 1.51 FGLGear.h, 1.26, 1.27

[Jon S. B. <jb...@us...>]

Update of /cvsroot/jsbsim/JSBSim/src/models
In directory fdv4jf1.ch3.sourceforge.com:/tmp/cvs-serv21764/src/models

Modified Files:
	FGLGear.cpp FGLGear.h 
Log Message:
Implementation of Pacejka's Magic Formula for landing gear

Index: FGLGear.cpp
===================================================================
RCS file: /cvsroot/jsbsim/JSBSim/src/models/FGLGear.cpp,v
retrieving revision 1.50
retrieving revision 1.51
diff -C2 -r1.50 -r1.51
*** FGLGear.cpp	5 Feb 2009 04:59:54 -0000	1.50
--- FGLGear.cpp	17 Feb 2009 08:04:15 -0000	1.51
***************
*** 247,326 ****
    CosWheel = 0.0;
  
!   Debug(0);
! }
  
! //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  
! FGLGear::FGLGear(const FGLGear& lgear)
! {
!   GearNumber = lgear.GearNumber;
!   State    = lgear.State;
!   Aircraft = lgear.Aircraft;
!   Propagate = lgear.Propagate;
!   Auxiliary = lgear.Auxiliary;
!   Exec     = lgear.Exec;
!   FCS      = lgear.FCS;
!   MassBalance = lgear.MassBalance;
! 
!   vXYZ = lgear.vXYZ;
!   vMoment = lgear.vMoment;
!   vWhlBodyVec = lgear.vWhlBodyVec;
!   vLocalGear = lgear.vLocalGear;
! 
!   WOW                = lgear.WOW;
!   lastWOW            = lgear.lastWOW;
!   ReportEnable       = lgear.ReportEnable;
!   FirstContact       = lgear.FirstContact;
!   StartedGroundRun   = lgear.StartedGroundRun;
!   LandingDistanceTraveled   = lgear.LandingDistanceTraveled;
!   TakeoffDistanceTraveled   = lgear.TakeoffDistanceTraveled;
!   TakeoffDistanceTraveled50ft   = lgear.TakeoffDistanceTraveled50ft;
!   MaximumStrutForce  = lgear.MaximumStrutForce;
!   MaximumStrutTravel = lgear.MaximumStrutTravel;
!   SideForce          = lgear.SideForce;
!   RollingForce       = lgear.RollingForce;
! 
!   kSpring         = lgear.kSpring;
!   bDamp           = lgear.bDamp;
!   bDampRebound    = lgear.bDampRebound;
!   compressLength  = lgear.compressLength;
!   compressSpeed   = lgear.compressSpeed;
!   staticFCoeff    = lgear.staticFCoeff;
!   dynamicFCoeff   = lgear.dynamicFCoeff;
!   rollingFCoeff   = lgear.rollingFCoeff;
!   brakePct        = lgear.brakePct;
!   maxCompLen      = lgear.maxCompLen;
!   SinkRate        = lgear.SinkRate;
!   GroundSpeed     = lgear.GroundSpeed;
!   LandingReported = lgear.LandingReported;
!   TakeoffReported = lgear.TakeoffReported;
!   name            = lgear.name;
!   sSteerType      = lgear.sSteerType;
!   sRetractable    = lgear.sRetractable;
!   sContactType    = lgear.sContactType;
!   eContactType    = lgear.eContactType;
!   sBrakeGroup     = lgear.sBrakeGroup;
!   eSteerType      = lgear.eSteerType;
!   eBrakeGrp       = lgear.eBrakeGrp;
!   maxSteerAngle   = lgear.maxSteerAngle;
!   isRetractable   = lgear.isRetractable;
!   GearUp          = lgear.GearUp;
!   GearDown        = lgear.GearDown;
!   GearPos         = lgear.GearPos;
!   useFCSGearPos   = lgear.useFCSGearPos;
!   WheelSlip       = lgear.WheelSlip;
!   TirePressureNorm = lgear.TirePressureNorm;
!   Servicable      = lgear.Servicable;
!   ForceY_Table    = lgear.ForceY_Table;
!   CosWheel        = lgear.CosWheel;
!   SinWheel        = lgear.SinWheel;
!   RFRV            = lgear.RFRV;
!   SFRV            = lgear.SFRV;
!   LongForceLagFilterCoeff = lgear.LongForceLagFilterCoeff;
!   LatForceLagFilterCoeff = lgear.LatForceLagFilterCoeff;
!   WheelSlipLagFilterCoeff = lgear.WheelSlipLagFilterCoeff;
!   WheelSlipFilter = lgear.WheelSlipFilter;
!   LongForceFilter = lgear.LongForceFilter;
!   LatForceFilter = lgear.LatForceFilter;
  }
  
--- 247,258 ----
    CosWheel = 0.0;
  
!   // Set Pacejka terms
  
!   Stiffness = 0.06;
!   Shape = 2.8;
!   Peak = staticFCoeff;
!   Curvature = 1.03;
  
!   Debug(0);
  }
  
***************
*** 625,649 ****
  
  //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
! // Compute the sideforce coefficients using similar assumptions to LaRCSim for now.
! // Allow a maximum of 10 degrees tire slip angle before wheel slides.  At that point,
! // transition from static to dynamic friction.  There are more complicated formulations
! // of this that avoid the discrete jump (similar to Pacejka).  Will fix this later.
  
  void FGLGear::ComputeSideForceCoefficient(void)
  {
    if (ForceY_Table) {
- 
      FCoeff = ForceY_Table->GetValue(WheelSlip);
- 
    } else {
! 
!     if (fabs(WheelSlip) <= 10.0) {
!       FCoeff = staticFCoeff*WheelSlip/10.0;
!     } else if (fabs(WheelSlip) <= 40.0) {
!       FCoeff = (dynamicFCoeff*(fabs(WheelSlip) - 10.0)/10.0
!                 + staticFCoeff*(40.0 - fabs(WheelSlip))/10.0)*(WheelSlip>=0?1.0:-1.0);
!     } else {
!       FCoeff = dynamicFCoeff*(WheelSlip>=0?1.0:-1.0);
!     }
    }
  }
--- 557,576 ----
  
  //%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
! // Compute the sideforce coefficients using Pacejka's Magic Formula.
! //
! //   y(x) = D sin {C arctan [Bx - E(Bx - arctan Bx)]}
! //
! // Where: B = Stiffness Factor (0.06, here)
! //        C = Shape Factor (2.8, here)
! //        D = Peak Factor (0.8, here)
! //        E = Curvature Factor (1.03, here)
  
  void FGLGear::ComputeSideForceCoefficient(void)
  {
    if (ForceY_Table) {
      FCoeff = ForceY_Table->GetValue(WheelSlip);
    } else {
!     double StiffSlip = Stiffness*WheelSlip;
!     FCoeff = Peak * sin(Shape*atan(StiffSlip - Curvature*(StiffSlip - atan(StiffSlip))));
    }
  }
***************
*** 714,717 ****
--- 641,646 ----
      property_name = base_property_name + "/compression-ft";
      Exec->GetPropertyManager()->Tie( property_name.c_str(), &compressLength );
+     property_name = base_property_name + "/side_friction_coeff";
+     Exec->GetPropertyManager()->Tie( property_name.c_str(), &FCoeff );
    }
  

Index: FGLGear.h
===================================================================
RCS file: /cvsroot/jsbsim/JSBSim/src/models/FGLGear.h,v
retrieving revision 1.26
retrieving revision 1.27
diff -C2 -r1.26 -r1.27
*** FGLGear.h	5 Feb 2009 04:59:54 -0000	1.26
--- FGLGear.h	17 Feb 2009 08:04:15 -0000	1.27
***************
*** 219,225 ****
    */
    FGLGear(Element* el, FGFDMExec* Executive, int number);
-   /** Constructor
-       @param lgear a reference to an existing FGLGear object     */
-   FGLGear(const FGLGear& lgear);
    /// Destructor
    ~FGLGear();
--- 219,222 ----
***************
*** 314,317 ****
--- 311,315 ----
    double compressSpeed;
    double staticFCoeff, dynamicFCoeff, rollingFCoeff;
+   double Stiffness, Shape, Peak, Curvature; // Pacejka factors
    double brakePct;
    double BrakeFCoeff;