$Header$
$Log$
-Revision 1.10 1999/11/03 16:46:24 curt
-Patches from Tony to enable brakes.
-
-Revision 1.9 1999/11/01 18:17:16 curt
-c172 updates from Tony. Fix extra yaw when using ailerons. Flaps and elevator
-tweaks.
+Revision 1.11 1999/11/15 22:54:07 curt
+Updates from Tony, mostly to landing gear.
----------------------------------------------------------------------------
#include "ls_generic.h"
#include "ls_cockpit.h"
+#define HEIGHT_AGL_WHEEL d_wheel_rwy_local_v[2]
+
sub3( DATA v1[], DATA v2[], DATA result[] )
{
gear()
{
char rcsid[] = "$Id$";
-
+char gear_strings[3][12]={"nose","right main", "left main"};
/*
* Aircraft specific initializations and data goes here
*/
static int num_wheels = NUM_WHEELS; /* number of wheels */
static DATA d_wheel_rp_body_v[NUM_WHEELS][3] = /* X, Y, Z locations */
{
- { 10., 0., 4. }, /* in feet */
- { -1., 3., 4. },
- { -1., -3., 4. }
+ { 5, 0., 7.0 }, /*nose*/ /* in feet */
+ { -2.0, 3.6, 6.5 }, /*right main*/
+ { -2.0, -3.6, 6.5 } /*left main*/
};
static DATA spring_constant[NUM_WHEELS] = /* springiness, lbs/ft */
{ 1500., 5000., 5000. };
static DATA spring_damping[NUM_WHEELS] = /* damping, lbs/ft/sec */
- { 100., 150., 150. };
+ { 1000., 1500., 1500. };
static DATA percent_brake[NUM_WHEELS] = /* percent applied braking */
{ 0., 0., 0. }; /* 0 = none, 1 = full */
static DATA caster_angle_rad[NUM_WHEELS] = /* steerable tires - in */
percent_brake[1] = Brake_pct; /* replace with cockpit brake handle connection code */
percent_brake[2] = percent_brake[1];
- caster_angle_rad[0] = 0.03*Rudder_pedal;
+ caster_angle_rad[0] = 0.52*Rudder_pedal;
- for (i=0;i<num_wheels;i++) /* Loop for each wheel */
+
+ for (i=0;i<num_wheels;i++) /* Loop for each wheel */
{
- /*========================================*/
- /* Calculate wheel position w.r.t. runway */
- /*========================================*/
-
- /* First calculate wheel location w.r.t. cg in body (X-Y-Z) axes... */
-
- sub3( d_wheel_rp_body_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, temp3b );
+ /* printf("%s:\n",gear_strings[i]); */
- /* plus contribution due to cg velocities */
+ /*========================================*/
+ /* Calculate wheel position w.r.t. runway */
+ /*========================================*/
- add3( temp3b, V_local_rel_ground_v, v_wheel_local_v );
-
-
- /*===========================================*/
- /* 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;
+ /* First calculate wheel location w.r.t. cg in body (X-Y-Z) axes... */
+
+ sub3( d_wheel_rp_body_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, temp3b );
+
+ /* plus contribution due to cg velocities */
+
+ add3( temp3b, 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 = spring_constant[i]*HEIGHT_AGL_WHEEL
+ - v_wheel_local_v[2]*spring_damping[i];
+ if (reaction_normal_force > 0.) reaction_normal_force = 0.;
+ /* to prevent damping component from swamping spring component */
+
+
+ /* Calculate friction coefficients */
+
+ forward_mu = (max_brake_mu - rolling_mu)*percent_brake[i] + rolling_mu;
+ abs_v_wheel_sideward = sqrt(v_wheel_sideward*v_wheel_sideward);
+ sideward_mu = sliding_mu;
+ 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.;
+
+ /* 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\n",reaction_normal_force,HEIGHT_AGL_WHEEL);
+ 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); */
- /* Calculate normal load force (simple spring constant) */
-
- reaction_normal_force = 0.;
- if( d_wheel_rwy_local_v[2] < 0. )
- {
- reaction_normal_force = spring_constant[i]*d_wheel_rwy_local_v[2]
- - v_wheel_local_v[2]*spring_damping[i];
- if (reaction_normal_force > 0.) reaction_normal_force = 0.;
- /* to prevent damping component from swamping spring component */
- }
-
- /* Calculate friction coefficients */
-
- forward_mu = (max_brake_mu - rolling_mu)*percent_brake[i] + rolling_mu;
- abs_v_wheel_sideward = sqrt(v_wheel_sideward*v_wheel_sideward);
- sideward_mu = sliding_mu;
- 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.;
-
- /* 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;
-
- /* 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 );
-
}
}
void do_trims(int kmax,FILE *out,InitialConditions IC)
{
- int k=0,i,j;
+ int bad_trim=0,i,j;
double speed,elevator,cmcl,maxspeed;
out=fopen("trims.out","w");
speed=55;
- for(j=0;j<=30;j+=10)
+ for(j=0;j<=0;j+=10)
{
IC.flap_handle=j;
- for(i=1;i<=5;i++)
+ for(i=4;i<=4;i++)
{
switch(i)
{
case 1: IC.weight=1500;IC.cg=0.155;break;
case 2: IC.weight=1500;IC.cg=0.364;break;
case 3: IC.weight=1950;IC.cg=0.155;break;
- case 4: IC.weight=2550;IC.cg=0.257;break;
+ case 4: IC.weight=2400;IC.cg=0.257;break;
case 5: IC.weight=2550;IC.cg=0.364;break;
}
IC.vc=speed;
Long_control=0;Theta=0;Throttle_pct=0.0;
- k=trim_long(kmax,IC);
+ bad_trim=trim_long(kmax,IC);
if(Long_control <= 0)
elevator=Long_control*28;
else
{
cmcl=cm / CL;
}
- if(k < kmax)
+ if(!bad_trim)
{
- fprintf(out,"%g,%g,%g,%g,%g,%d",V_calibrated_kts,Alpha*RAD_TO_DEG,Long_control,Throttle_pct,Flap_Position,k);
+ fprintf(out,"%g,%g,%g,%g,%g",V_calibrated_kts,Alpha*RAD_TO_DEG,Long_control,Throttle_pct,Flap_Position);
fprintf(out,",%g,%g,%g,%g,%g\n",CL,cm,cmcl,Weight,Cg);
/* printf("%g,%g,%g,%g,%g,%g,%g,%g,%g,%g\n",V_calibrated_kts,Alpha*RAD_TO_DEG,elevator,CL,cm,Cmo,Cma,Cmde,Mass*32.174,Dx_cg);
*/ }
else
{
- printf("kmax exceeded at: %g knots, %g lbs, %g %%MAC, Flaps: %g\n",V_calibrated_kts,Weight,Cg,Flap_Position);
+ printf("kmax exceeded at: %g knots, %g lbs, %g %%MAC, Flaps: %g\n",V_true_kts,Weight,Cg,Flap_Position);
printf("wdot: %g, udot: %g, qdot: %g\n",W_dot_body,U_dot_body,Q_dot_body);
printf("Alpha: %g, Throttle_pct: %g, Long_control: %g\n\n",Alpha*RAD_TO_DEG,Throttle_pct,Long_control);
}
}
}
fclose(out);
-}
+}
+
+find_max_alt(int kmax,InitialConditions IC)
+{
+ int bad_trim=0,i=0;
+ float min=0,max=30000;
+ IC.use_gamma_tmg=1;
+ IC.gamma=0;
+ IC.vc=73;
+ IC.altitude==1000;
+ while(!bad_trim)
+ {
+ bad_trim=trim_long(200,IC);
+ IC.altitude+=1000;
+ }
+ while((fabs(max-min) > 100) && (i < 50))
+ {
+
+ IC.altitude=(max-min)/2 + min;
+ printf("\nIC.altitude: %g, max: %g, min: %g, bad_trim: %d\n",IC.altitude,max,min,bad_trim);
+ printf("Alpha: %g, Throttle_pct: %g, Long_control: %g\n\n",Alpha*RAD_TO_DEG,Throttle_pct,Long_control);
+
+ bad_trim=trim_long(200,IC);
+
+ if(bad_trim == 1 )
+ max=IC.altitude;
+ else
+ min=IC.altitude;
+ i++;
+ }
+}
+
void find_trim_stall(int kmax,FILE *out,InitialConditions IC)
{
IC.latitude=47.5299892; //BFI
IC.longitude=122.3019561;
Runway_altitude = 18.0;
+
IC.altitude=strtod(argv[2],NULL);
+ printf("h: %g, argv[2]: %s\n",IC.altitude,argv[2]);
IC.vc=strtod(argv[1],NULL);
IC.alpha=0;
IC.beta=0;
- IC.gamma=strtod(argv[3],NULL);
- IC.use_gamma_tmg=1;
- IC.phi=0;
- IC.psi=10;
- IC.weight=2300;
+ IC.theta=strtod(argv[3],NULL);
+ IC.use_gamma_tmg=0;
+ IC.phi=strtod(argv[4],NULL);
+ IC.psi=0;
+ IC.weight=2400;
IC.cg=0.25;
IC.flap_handle=0;
- IC.long_control=strtod(argv[4],NULL);
+ IC.long_control=0;
IC.rudder_pedal=0;
printf("IC.vc: %g\n",IC.vc);
ls_ForceAltitude(IC.altitude);
fgLaRCsimInit(0.01);
- printf("\nLong_control: %g\n\n",Long_control);
-
-
- IC.cg=0.155;
- IC.alpha=-5;
- setIC(IC);ls_loop(0.0,-1);
- newcm=CLwbh*(IC.cg - 0.557);
- lastcm=newcm;
- out=fopen("cmcl.out","w");
- while(IC.alpha < 22)
- {
- IC.alpha+=1;
- setIC(IC);ls_loop(0.0,-1);
- newcm=CLwbh*(IC.cg - 0.557);
- cmalpha=newcm-lastcm;
- printf("alpha: %4.0f, CL: %5.2f, Cm: %5.2f, Cma: %7.4f\n",Alpha*RAD_TO_DEG,CLwbh,newcm,cmalpha);
- fprintf(out,"%g %g\n",newcm,CLwbh);
- lastcm=newcm;
- }
- fclose(out);
- /* find_trim_stall(200,out,IC);
-
- IC.vc=120;
- IC.altitude=8000;
- IC.weight=2300;
- IC.cg=0.25;
- IC.flap_handle=0;
-
-
- setIC(IC);
- printIC(IC);
- k=trim_long(100,IC);
-
- printf("Flap_handle: %g, Flap_Position: %g\n",Flap_handle,Flap_Position);
- printf("k: %d, %g knots, %g lbs, %g %%MAC\n",k,V_calibrated_kts,Weight,Cg);
- printf("wdot: %g, udot: %g, qdot: %g\n",W_dot_body,U_dot_body,Q_dot_body);
- printf("Alpha: %g, Throttle_pct: %g, Long_control: %g\n\n",Alpha,Throttle_pct,Long_control);
-
- printf("Cme: %g, elevator: %g, Cmde: %g\n",elevator*Cmde,elevator,Cmde);
-
- IC.cg=0.155;
- setIC(IC);
- k=trim_long(100,IC);
-
- printf("Flap_handle: %g, Flap_Position: %g\n",Flap_handle,Flap_Position);
- printf("k: %d, %g knots, %g lbs, %g %%MAC\n",k,V_calibrated_kts,Weight,Cg);
- printf("wdot: %g, udot: %g, qdot: %g\n",W_dot_body,U_dot_body,Q_dot_body);
- printf("Alpha: %g, Throttle_pct: %g, Long_control: %g\n\n",Alpha,Throttle_pct,Long_control);
-
- printf("Cme: %g, elevator: %g, Cmde: %g\n",elevator*Cmde,elevator,Cmde);
-
- IC.cg=0.364;
setIC(IC);
- k=trim_long(100,IC);
+ ls_loop(0,-1);
+ printf("\nAltitude: %g\n\n",Altitude);
+ i=0;
+ while(i <= 1)
+ {
+ if(i > 0)
+ Brake_pct=1;
+ ls_update(1);
+ printf("\tAltitude: %g, Theta: %g, Phi: %g\n\n",Altitude,Theta*RAD_TO_DEG,Phi*RAD_TO_DEG);
+ i++;
+ }
+ printf("w: %g, u: %g, q: %g\n",W_body,U_body,Q_body);
+
- printf("Flap_handle: %g, Flap_Position: %g\n",Flap_handle,Flap_Position);
+ /*printf("Flap_handle: %g, Flap_Position: %g\n",Flap_handle,Flap_Position);
printf("k: %d, %g knots, %g lbs, %g %%MAC\n",k,V_calibrated_kts,Weight,Cg);
printf("wdot: %g, udot: %g, qdot: %g\n",W_dot_body,U_dot_body,Q_dot_body);
printf("Alpha: %g, Throttle_pct: %g, Long_control: %g\n\n",Alpha,Throttle_pct,Long_control);
- /* do_trims(400,out,IC); */
+
/* ls_loop(0.0,-1);
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