From: curt <curt>
Date: Thu, 29 Mar 2001 13:14:42 +0000 (+0000)
Subject: Initial revision.
X-Git-Url: https://git.mxchange.org/?a=commitdiff_plain;h=bfb2a65128eaf7fbdad632cc29aeb9570f67d1a7;p=flightgear.git

Initial revision.
---

diff --git a/src/FDM/UIUCModel/uiuc_gear.cpp b/src/FDM/UIUCModel/uiuc_gear.cpp
new file mode 100644
index 000000000..0e72ed4bf
--- /dev/null
+++ b/src/FDM/UIUCModel/uiuc_gear.cpp
@@ -0,0 +1,368 @@
+/**********************************************************************
+
+ FILENAME:     uiuc_gear.cpp
+
+----------------------------------------------------------------------
+
+ DESCRIPTION:  determine the gear forces and moments
+               
+----------------------------------------------------------------------
+
+ STATUS:       alpha version
+
+----------------------------------------------------------------------
+
+ REFERENCES:   based on c172_gear by Tony Peden and others
+
+----------------------------------------------------------------------
+
+ HISTORY:      03/09/2001   initial release
+
+----------------------------------------------------------------------
+
+ AUTHOR(S):    David Megginson <david@megginson.com
+
+----------------------------------------------------------------------
+
+ VARIABLES:    [TODO]
+
+----------------------------------------------------------------------
+
+ INPUTS:       [TODO]
+
+----------------------------------------------------------------------
+
+ OUTPUTS:      [TODO]
+
+----------------------------------------------------------------------
+
+ CALLED BY:   uiuc_wrapper.cpp 
+
+----------------------------------------------------------------------
+
+ CALLS TO:     none
+
+----------------------------------------------------------------------
+
+ COPYRIGHT:    (c) 2001 by David Megginson
+
+ 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.
+
+ 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 or view http://www.gnu.org/copyleft/gpl.html.
+
+**********************************************************************/
+
+#include <simgear/compiler.h>
+
+#include "uiuc_gear.h"
+
+SG_USING_STD(cerr);
+
+
+#define HEIGHT_AGL_WHEEL d_wheel_rwy_local_v[2]
+
+
+static void sub3( DATA v1[],  DATA v2[], DATA result[] )
+{
+    result[0] = v1[0] - v2[0];
+    result[1] = v1[1] - v2[1];
+    result[2] = v1[2] - v2[2];
+}
+
+static void add3( DATA v1[],  DATA v2[], DATA result[] )
+{
+    result[0] = v1[0] + v2[0];
+    result[1] = v1[1] + v2[1];
+    result[2] = v1[2] + v2[2];
+}
+
+static void cross3( DATA v1[],  DATA v2[], DATA result[] )
+{
+    result[0] = v1[1]*v2[2] - v1[2]*v2[1];
+    result[1] = v1[2]*v2[0] - v1[0]*v2[2];
+    result[2] = v1[0]*v2[1] - v1[1]*v2[0];
+}
+
+static void multtrans3x3by3( DATA m[][3], DATA v[], DATA result[] )
+{
+    result[0] = m[0][0]*v[0] + m[1][0]*v[1] + m[2][0]*v[2];
+    result[1] = m[0][1]*v[0] + m[1][1]*v[1] + m[2][1]*v[2];
+    result[2] = m[0][2]*v[0] + m[1][2]*v[1] + m[2][2]*v[2];
+}
+
+static void mult3x3by3( DATA m[][3], DATA v[], DATA result[] )
+{
+    result[0] = m[0][0]*v[0] + m[0][1]*v[1] + m[0][2]*v[2];
+    result[1] = m[1][0]*v[0] + m[1][1]*v[1] + m[1][2]*v[2];
+    result[2] = m[2][0]*v[0] + m[2][1]*v[1] + m[2][2]*v[2];
+}
+
+static void clear3( DATA v[] )
+{
+    v[0] = 0.; v[1] = 0.; v[2] = 0.;
+}
+
+void uiuc_gear()
+{
+
+  /*
+   * Aircraft specific initializations and data goes here
+   */
+   
+    static DATA percent_brake[MAX_GEAR] =	    /* percent applied braking */
+	{ 0.,  0.,  0., 0.,
+          0.,  0.,  0., 0.,
+          0.,  0.,  0., 0.,
+          0.,  0.,  0., 0. };			    /* 0 = none, 1 = full */
+    static DATA caster_angle_rad[MAX_GEAR] =	    /* steerable tires - in */
+        { 0., 0., 0., 0.,
+	  0., 0., 0., 0.,
+	  0., 0., 0., 0.,
+          0., 0., 0., 0. };                         /* radians, +CW */	
+  /*
+   * End of aircraft specific code
+   */
+    
+  /*
+   * Constants & coefficients for tyres on tarmac - ref [1]
+   */
+   
+    /* skid function looks like:
+     * 
+     *           mu  ^
+     *               |
+     *       max_mu  |       +		
+     *               |      /|		
+     *   sliding_mu  |     / +------	
+     *               |    /		
+     *               |   /		
+     *               +--+------------------------> 
+     *               |  |    |      sideward V
+     *               0 bkout skid
+     *	               V     V
+     */
+  
+  
+    static int it_rolls[MAX_GEAR] =
+    { 1, 1, 1, 0,
+      0, 0, 0, 0,
+      0, 0, 0, 0,
+      0, 0, 0, 0 };	
+    static DATA sliding_mu[MAX_GEAR] =
+    { 0.5, 0.5, 0.5, 0.3,
+      0.3, 0.3, 0.3, 0.3,
+      0.3, 0.3, 0.3, 0.3,
+      0.3, 0.3, 0.3, 0.3 };	
+    static DATA max_brake_mu[MAX_GEAR] =
+    { 0.0, 0.6, 0.6, 0.0,
+      0.0, 0.0, 0.0, 0.0,
+      0.0, 0.0, 0.0, 0.0,
+      0.0, 0.0, 0.0, 0.0 };	
+    static DATA max_mu	     = 0.8;	
+    static DATA bkout_v	     = 0.1;
+    static DATA skid_v       = 1.0;
+  /*
+   * Local data variables
+   */
+   
+    DATA d_wheel_cg_body_v[3];		/* wheel offset from cg,  X-Y-Z	*/
+    DATA d_wheel_cg_local_v[3];		/* wheel offset from cg,  N-E-D	*/
+    DATA d_wheel_rwy_local_v[3];	/* wheel offset from rwy, N-E-U */
+	DATA v_wheel_cg_local_v[3];    /*wheel velocity rel to cg N-E-D*/
+    DATA v_wheel_body_v[3];		/* wheel velocity,	  X-Y-Z	*/
+    DATA v_wheel_local_v[3];		/* wheel velocity,	  N-E-D	*/
+    DATA f_wheel_local_v[3];		/* wheel reaction force,  N-E-D	*/
+	DATA altitude_local_v[3];       /*altitude vector in local (N-E-D) i.e. (0,0,h)*/
+	DATA altitude_body_v[3];        /*altitude vector in body (X,Y,Z)*/
+    DATA temp3a[3], temp3b[3], tempF[3], tempM[3];	
+    DATA reaction_normal_force;		/* wheel normal (to rwy) force	*/
+    DATA cos_wheel_hdg_angle, sin_wheel_hdg_angle;	/* temp storage */
+    DATA v_wheel_forward, v_wheel_sideward,  abs_v_wheel_sideward;
+    DATA forward_mu, sideward_mu;	/* friction coefficients	*/
+    DATA beta_mu;			/* breakout friction slope	*/
+    DATA forward_wheel_force, sideward_wheel_force;
+
+    int i;				/* per wheel loop counter */
+
+  /*
+   * Execution starts here
+   */
+   
+    beta_mu = max_mu/(skid_v-bkout_v);
+    clear3( F_gear_v );		/* Initialize sum of forces...	*/
+    clear3( M_gear_v );		/* ...and moments		*/
+    
+  /*
+   * Put aircraft specific executable code here
+   */
+   
+    percent_brake[1] = Brake_pct[0];
+    percent_brake[2] = Brake_pct[1];
+    
+    caster_angle_rad[0] =
+	(0.01 + 0.04 * (1 - V_calibrated_kts / 130)) * Rudder_pedal;
+    
+    
+	for (i=0;i<MAX_GEAR;i++)	    /* Loop for each wheel */
+    {
+				// Execute only if the gear has been defined
+      if (!gear_model[i])
+	continue;
+
+		/* printf("%s:\n",gear_strings[i]); */
+
+
+
+		/*========================================*/
+		/* Calculate wheel position w.r.t. runway */
+		/*========================================*/
+
+		
+		/* printf("\thgcg: %g, theta: %g,phi: %g\n",D_cg_above_rwy,Theta*RAD_TO_DEG,Phi*RAD_TO_DEG); */
+
+		
+			/* First calculate wheel location w.r.t. cg in body (X-Y-Z) axes... */
+
+		sub3( D_gear_v[i], D_cg_rp_body_v, d_wheel_cg_body_v );
+
+	    	/* then converting to local (North-East-Down) axes... */
+
+		multtrans3x3by3( T_local_to_body_m,  d_wheel_cg_body_v, d_wheel_cg_local_v );
+		
+
+	    	/* Runway axes correction - third element is Altitude, not (-)Z... */
+
+		d_wheel_cg_local_v[2] = -d_wheel_cg_local_v[2]; /* since altitude = -Z */
+
+	    	/* Add wheel offset to cg location in local axes */
+
+		add3( d_wheel_cg_local_v, D_cg_rwy_local_v, d_wheel_rwy_local_v );
+
+	    	/* remove Runway axes correction so right hand rule applies */
+
+		d_wheel_cg_local_v[2] = -d_wheel_cg_local_v[2]; /* now Z positive down */
+
+		/*============================*/
+		/* Calculate wheel velocities */
+		/*============================*/
+
+	    	/* contribution due to angular rates */
+
+		cross3( Omega_body_v, d_wheel_cg_body_v, temp3a );
+
+	    	/* transform into local axes */
+
+		multtrans3x3by3( T_local_to_body_m, temp3a,v_wheel_cg_local_v );
+
+	    	/* plus contribution due to cg velocities */
+
+		add3( v_wheel_cg_local_v, V_local_rel_ground_v, v_wheel_local_v );
+
+		clear3(f_wheel_local_v);
+		reaction_normal_force=0;
+		if( HEIGHT_AGL_WHEEL < 0. ) 
+			/*the wheel is underground -- which implies ground contact 
+			  so calculate reaction forces */ 
+			{
+			/*===========================================*/
+			/* Calculate forces & moments for this wheel */
+			/*===========================================*/
+
+	    		/* Add any anticipation, or frame lead/prediction, here... */
+
+		    		/* no lead used at present */
+
+	    		/* Calculate sideward and forward velocities of the wheel 
+		    		in the runway plane					*/
+
+			cos_wheel_hdg_angle = cos(caster_angle_rad[i] + Psi);
+			sin_wheel_hdg_angle = sin(caster_angle_rad[i] + Psi);
+
+			v_wheel_forward  = v_wheel_local_v[0]*cos_wheel_hdg_angle
+					 + v_wheel_local_v[1]*sin_wheel_hdg_angle;
+			v_wheel_sideward = v_wheel_local_v[1]*cos_wheel_hdg_angle
+					 - v_wheel_local_v[0]*sin_wheel_hdg_angle;
+			
+	            
+	    	/* Calculate normal load force (simple spring constant) */
+
+	    	reaction_normal_force = 0.;
+        
+	    	reaction_normal_force = kgear[i]*d_wheel_rwy_local_v[2]
+					  - v_wheel_local_v[2]*cgear[i];
+			/* printf("\treaction_normal_force: %g\n",reaction_normal_force); */
+
+	    	if (reaction_normal_force > 0.) reaction_normal_force = 0.;
+			/* to prevent damping component from swamping spring component */
+
+
+	    	/* Calculate friction coefficients */
+
+			if(it_rolls[i])
+			{
+			   forward_mu = (max_brake_mu[i] - muGear[i])*percent_brake[i] + muGear[i];
+			   abs_v_wheel_sideward = sqrt(v_wheel_sideward*v_wheel_sideward);
+			   sideward_mu = sliding_mu[i];
+			   if (abs_v_wheel_sideward < skid_v) 
+	    		   sideward_mu = (abs_v_wheel_sideward - bkout_v)*beta_mu;
+			   if (abs_v_wheel_sideward < bkout_v) sideward_mu = 0.;
+			}
+			else
+			{
+				forward_mu=sliding_mu[i];
+				sideward_mu=sliding_mu[i];
+			}	   
+
+	    		/* Calculate foreward and sideward reaction forces */
+
+			forward_wheel_force  =   forward_mu*reaction_normal_force;
+			sideward_wheel_force =  sideward_mu*reaction_normal_force;
+			if(v_wheel_forward < 0.) forward_wheel_force = -forward_wheel_force;
+			if(v_wheel_sideward < 0.) sideward_wheel_force = -sideward_wheel_force;
+/* 			printf("\tFfwdgear: %g Fsidegear: %g\n",forward_wheel_force,sideward_wheel_force);
+ */
+	    		/* Rotate into local (N-E-D) axes */
+
+			f_wheel_local_v[0] = forward_wheel_force*cos_wheel_hdg_angle
+					  - sideward_wheel_force*sin_wheel_hdg_angle;
+			f_wheel_local_v[1] = forward_wheel_force*sin_wheel_hdg_angle
+					  + sideward_wheel_force*cos_wheel_hdg_angle;
+			f_wheel_local_v[2] = reaction_normal_force;	  
+
+			 /* Convert reaction force from local (N-E-D) axes to body (X-Y-Z) */
+			mult3x3by3( T_local_to_body_m, f_wheel_local_v, tempF );
+
+	    		/* Calculate moments from force and offsets in body axes */
+
+			cross3( d_wheel_cg_body_v, tempF, tempM );
+
+			/* Sum forces and moments across all wheels */
+
+			add3( tempF, F_gear_v, F_gear_v );
+			add3( tempM, M_gear_v, M_gear_v );   
+
+
+			}
+
+
+
+		/* printf("\tN: %g,dZrwy: %g dZdotrwy: %g\n",reaction_normal_force,HEIGHT_AGL_WHEEL,v_wheel_cg_local_v[2]); */
+
+		/*printf("\tFxgear: %g Fygear: %g, Fzgear: %g\n",F_X_gear,F_Y_gear,F_Z_gear);
+		printf("\tMgear: %g, Lgear: %g, Ngear: %g\n\n",M_m_gear,M_l_gear,M_n_gear); */
+
+
+    }
+}
+
+// end uiuc_engine.cpp
diff --git a/src/FDM/UIUCModel/uiuc_gear.h b/src/FDM/UIUCModel/uiuc_gear.h
new file mode 100644
index 000000000..3dc2f9ffc
--- /dev/null
+++ b/src/FDM/UIUCModel/uiuc_gear.h
@@ -0,0 +1,9 @@
+#ifndef _GEAR_H_
+#define _GEAR_H_
+
+#include "uiuc_aircraft.h"
+#include <FDM/LaRCsim/ls_generic.h>
+#include <FDM/LaRCsim/ls_cockpit.h>
+
+void uiuc_gear();
+#endif // _GEAR_H_
diff --git a/src/FDM/UIUCModel/uiuc_map_gear.cpp b/src/FDM/UIUCModel/uiuc_map_gear.cpp
new file mode 100644
index 000000000..a56e455b4
--- /dev/null
+++ b/src/FDM/UIUCModel/uiuc_map_gear.cpp
@@ -0,0 +1,80 @@
+/********************************************************************** 
+ 
+ FILENAME:     uiuc_map_gear.cpp 
+
+---------------------------------------------------------------------- 
+
+ DESCRIPTION:  initializes the gear map
+
+----------------------------------------------------------------------
+ 
+ STATUS:       alpha version
+
+----------------------------------------------------------------------
+ 
+ REFERENCES:   
+ 
+----------------------------------------------------------------------
+ 
+ HISTORY:      04/08/2000   initial release
+
+----------------------------------------------------------------------
+ 
+ AUTHOR(S):    Bipin Sehgal       <bsehgal@uiuc.edu>
+               Jeff Scott         <jscott@mail.com>
+ 
+----------------------------------------------------------------------
+ 
+ VARIABLES:
+ 
+----------------------------------------------------------------------
+ 
+ INPUTS:       none
+ 
+----------------------------------------------------------------------
+ 
+ OUTPUTS:      none
+ 
+----------------------------------------------------------------------
+ 
+ CALLED BY:    uiuc_initializemaps.cpp
+ 
+----------------------------------------------------------------------
+ 
+ CALLS TO:     none
+ 
+----------------------------------------------------------------------
+ 
+ COPYRIGHT:    (C) 2000 by Michael Selig
+ 
+ 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.
+ 
+ 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 or view http://www.gnu.org/copyleft/gpl.html.
+ 
+**********************************************************************/
+
+#include "uiuc_map_gear.h"
+
+
+void uiuc_map_gear()
+{
+  gear_map["Dx_gear"]             =      Dx_gear_flag               ;
+  gear_map["Dy_gear"]             =      Dy_gear_flag               ;
+  gear_map["Dz_gear"]             =      Dz_gear_flag               ;
+  gear_map["cgear"]               =      cgear_flag                 ;
+  gear_map["kgear"]               =      kgear_flag                 ;
+  gear_map["muGear"]              =      muGear_flag                ;
+  gear_map["strutLength"]         =      strutLength_flag           ;
+}
+
+// end uiuc_map_gear.cpp
diff --git a/src/FDM/UIUCModel/uiuc_map_gear.h b/src/FDM/UIUCModel/uiuc_map_gear.h
new file mode 100644
index 000000000..86d75ea90
--- /dev/null
+++ b/src/FDM/UIUCModel/uiuc_map_gear.h
@@ -0,0 +1,8 @@
+#ifndef _MAP_GEAR_H_
+#define _MAP_GEAR_H_
+
+#include "uiuc_aircraft.h"
+
+void uiuc_map_gear();
+
+#endif  // _MAP_GEAR_H_