// LaRCsim.cxx -- interface to the LaRCsim flight model // // Written by Curtis Olson, started October 1998. // // Copyright (C) 1998 Curtis L. Olson - curt@me.umn.edu // // 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., 675 Mass Ave, Cambridge, MA 02139, USA. // // $Id$ #include #include #include #include #include /* #include */ #include #include #include #include #include #include void do_trims(int kmax,FILE *out,InitialConditions IC) { int bad_trim=0,i,j; double speed,elevator,cmcl,maxspeed; out=fopen("trims.out","w"); speed=55; for(j=0;j<=0;j+=10) { IC.flap_handle=j; 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=2400;IC.cg=0.257;break; case 5: IC.weight=2550;IC.cg=0.364;break; } speed=40; if(j > 0) { maxspeed = 90; } else { maxspeed = 170; } while(speed <= maxspeed) { IC.vc=speed; Long_control=0;Theta=0;Throttle_pct=0.0; bad_trim=trim_long(kmax,IC); if(Long_control <= 0) elevator=Long_control*28; else elevator=Long_control*23; if(fabs(CL) > 1E-3) { cmcl=cm / CL; } if(!bad_trim) { 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_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); } speed+=10; } } } 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) { int k=0,i,j; int failf; char axis[10]; double speed,elevator,cmcl,speed_inc,lastgood; out=fopen("trim_stall.summary","w"); speed=90; speed_inc=10; //failf=malloc(sizeof(int)); for(j=0;j<=30;j+=10) { IC.flap_handle=j; for(i=1;i<=6;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=2400;IC.cg=0.155;break; case 4: IC.weight=2400;IC.cg=0.364;break; case 5: IC.weight=2550;IC.cg=0.257;break; case 6: IC.weight=2550;IC.cg=0.364;break; } speed=90; speed_inc=10; while(speed_inc >= 0.5) { IC.vc=speed; Long_control=0;Theta=0;Throttle_pct=0.0; failf=trim_longfr(kmax,IC); if(Long_control <= 0) elevator=Long_control*28; else elevator=Long_control*23; if(fabs(CL) > 1E-3) { cmcl=cm / CL; } if(failf == 0) { lastgood=speed; axis[0]='\0'; //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\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("trim failed at: %g knots, %g lbs, %g %%MAC, Flaps: %g\n",V_calibrated_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); printf("Speed increment: %g\n",speed_inc); speed+=speed_inc; speed_inc/=2; } speed-=speed_inc; } printf("failf %d\n",failf); if(failf == 1) strcpy(axis,"lift"); else if(failf == 2) strcpy(axis,"thrust"); else if(failf == 3) strcpy(axis,"pitch"); fprintf(out,"Last good speed: %g, Flaps: %g, Weight: %g, CG: %g, failed axis: %s\n",lastgood,Flap_handle,Weight,Cg,axis); } } fclose(out); //free(failf); } // Initialize the LaRCsim flight model, dt is the time increment for // each subsequent iteration through the EOM int fgLaRCsimInit(double dt) { ls_toplevel_init(dt); return(1); } int wave_stats(float *var,float *var_rate,int N,FILE *out) { int Nc,i,Nmaxima; float varmax,slope,intercept,time,ld,zeta,omegad,omegan; float varmaxima[100],vm_times[100]; /*adjust N so that any constant slope region at the end is cut off */ i=N; while((fabs(var_rate[N]-var_rate[i]) < 0.1) && (i >= 0)) { i--; } Nc=N-i; slope=(var[N]-var[Nc])/(N*0.01 - Nc*0.01); intercept=var[N]-slope*N*0.01; printf("\tRotating constant decay out of data using:\n"); printf("\tslope: %g, intercept: %g\n",slope,intercept); printf("\tUsing first %d points for dynamic response analysis\n",Nc); varmax=0; Nmaxima=0;i=0; while((i <= Nc) && (i <= 801)) { fprintf(out,"%g\t%g",i*0.01,var[i]); var[i]-=slope*i*0.01+intercept; /* printf("%g\n",var[i]); */ fprintf(out,"\t%g\n",var[i]); if(var[i] > varmax) { varmax=var[i]; time=i*0.01; } if((var[i-1]*var[i] < 0) && (var[i] > 0)) { varmaxima[Nmaxima]=varmax; vm_times[Nmaxima]=time; printf("\t%6.2f: %8.4f\n",vm_times[Nmaxima],varmaxima[Nmaxima]); varmax=0;Nmaxima++; } i++; } varmaxima[Nmaxima]=varmax; vm_times[Nmaxima]=time; Nmaxima++; if(Nmaxima > 2) { ld=log(varmaxima[1]/varmaxima[2]); //logarithmic decrement zeta=ld/sqrt(4*PI*PI +ld*ld); //damping ratio omegad=1/(vm_times[2]-vm_times[1]); //damped natural frequency Hz if(zeta < 1) { omegan=omegad/sqrt(1-zeta*zeta); //natural frequency Hz } printf("\tDamping Ratio: %g\n",zeta); printf("\tDamped Freqency: %g Hz\n\tNatural Freqency: %g Hz\n",omegad,omegan); } else printf("\tNot enough points to take log decrement\n"); /* printf("w: %g, u: %g, q: %g\n",W_body,U_body,Q_body); */ return 1; } // Run an iteration of the EOM (equations of motion) int main(int argc, char *argv[]) { double save_alt = 0.0; int multiloop=1,k=0,i,j,touchdown,N; double time=0,elev_trim,elev_trim_save,elevator,speed,cmcl; FILE *out; double hgain,hdiffgain,herr,herrprev,herr_diff,htarget; double lastVt,vtdots,vtdott; InitialConditions IC; SCALAR *control[7]; SCALAR *state[7]; float old_state,effectiveness,tol,delta_state,lctrim; float newcm,lastcm,cmalpha,td_vspeed,td_time,stop_time; float h[801],hdot[801],altmin,lastAlt,theta[800],theta_dot[800]; if(argc < 6) { printf("Need args: $c172 speed alt alpha elev throttle\n"); exit(1); } initIC(&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.theta=strtod(argv[3],NULL); IC.use_gamma_tmg=0; IC.phi=0; IC.psi=0; IC.weight=2400; IC.cg=0.25; IC.flap_handle=30; IC.long_control=0; IC.rudder_pedal=0; ls_ForceAltitude(IC.altitude); fgLaRCsimInit(0.01); setIC(IC); printf("Dx_cg: %g\n",Dx_cg); V_down=strtod(argv[4],NULL);; ls_loop(0,-1); i=0;time=0; IC.long_control=0; altmin=Altitude; printf("\tAltitude: %g, Theta: %g, V_down: %g\n\n",Altitude,Theta*RAD_TO_DEG,V_down); printf("%12s %10s %10s\n","Alpha (deg)","Alpha","Drag"); for(i=-5;i<=22;i++) { IC.alpha=i; setIC(IC); ls_loop(0,-1); printf("%12f %10f %10f\n",Alpha*RAD_TO_DEG,Alpha,cd); } /*out=fopen("drop.out","w"); N=800;touchdown=0; while(i <= N) { ls_update(1); printf("\tAltitude: %g, Theta: %g, V_down: %g\n\n",D_cg_above_rwy,Theta*RAD_TO_DEG,V_down); fprintf(out,"%g\t%g\t%g\t%g\t%g\t%g\n",time,D_cg_above_rwy,Theta*RAD_TO_DEG,V_down,F_Z_gear/1000.0,V_rel_ground); h[i]=D_cg_above_rwy;hdot[i]=V_down; theta[i]=Theta; theta_dot[i]=Theta_dot; if(D_cg_above_rwy < altmin) altmin=D_cg_above_rwy; if((F_Z_gear < -10) && (! touchdown)) { touchdown=1; td_vspeed=V_down; td_time=time; } time+=0.01; i++; } while(V_rel_ground > 1) { if(Brake_pct < 1) { Brake_pct+=0.02; } ls_update(1); time=i*0.01; fprintf(out,"%g\t%g\t%g\t%g\t%g\t%g\n",time,D_cg_above_rwy,Theta*RAD_TO_DEG,V_down,F_Z_gear/1000.0,V_rel_ground); i++; } stop_time=time; while((time-stop_time) < 5.0) { ls_update(1); time=i*0.01; fprintf(out,"%g\t%g\t%g\t%g\t%g\t%g\n",time,D_cg_above_rwy,Theta*RAD_TO_DEG,V_down,F_Z_gear/1000.0,V_rel_ground); i++; } fclose(out); printf("Min Altitude: %g, Final Alitutde: %g, Delta: %g\n",altmin, h[N], D_cg_above_rwy-altmin); printf("Vertical Speed at touchdown: %g, Time at touchdown: %g\n",td_vspeed,td_time); printf("\nAltitude response:\n"); out=fopen("alt.out","w"); wave_stats(h,hdot,N,out); fclose(out); out=fopen("theta.out","w"); printf("\nPitch Attitude response:\n"); wave_stats(theta,theta_dot,N,out); fclose(out);*/ /*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); */ /* ls_loop(0.0,-1); control[1]=&IC.long_control; control[2]=&IC.throttle; control[3]=&IC.alpha; control[4]=&IC.beta; control[5]=&IC.phi; control[6]=&IC.lat_control; state[1]=&Q_dot_body;state[2]=&U_dot_body;state[3]=&W_dot_body; state[4]=&R_dot_body;state[5]=&V_dot_body;state[6]=&P_dot_body; for(i=1;i<=6;i++) { old_state=*state[i]; tol=1E-4; for(j=1;j<=6;j++) { *control[j]+=0.1; setIC(IC); ls_loop(0.0,-1); delta_state=*state[i]-old_state; effectiveness=(delta_state)/ 0.1; if(delta_state < tol) effectiveness = 0; printf("%8.4f,",delta_state); *control[j]-=0.1; } printf("\n"); setIC(IC); ls_loop(0.0,-1); } */ return 1; } /* void do_stick_pull(int kmax, SCALAR tmax,FILE *out,InitialConditions IC) { SCALAR htarget,hgain,hdiffgain,herr,herr_diff,herrprev; SCALAR theta_trim,elev_trim,time; int k; k=trim_long(kmax,IC); printf("Trim:\n\tAlpha: %10.6f, elev: %10.6f, Throttle: %10.6f\n\twdot: %10.6f, qdot: %10.6f, udot: %10.6f\n",Alpha*RAD_TO_DEG,Long_control,Throttle_pct,W_dot_body,U_dot_body,Q_dot_body); htarget=0; hgain=1; hdiffgain=1; elev_trim=Long_control; out=fopen("stick_pull.out","w"); herr=Q_body-htarget; //fly steady-level for 2 seconds, well, zero pitch rate anyway while(time < 2.0) { herrprev=herr; ls_update(1); herr=Q_body-htarget; herr_diff=herr-herrprev; Long_control=elev_trim+(hgain*herr + hdiffgain*herr_diff); time+=0.01; //printf("Time: %7.4f, Alt: %7.4f, Alpha: %7.4f, pelev: %7.4f, qdot: %7.4f, udot: %7.4f, Phi: %7.4f, Psi: %7.4f\n",time,Altitude,Alpha*RAD_TO_DEG,Long_control*100,Q_body*RAD_TO_DEG,U_dot_body,Phi,Psi); //printf("Mcg: %7.4f, Mrp: %7.4f, Maero: %7.4f, Meng: %7.4f, Mgear: %7.4f, Dx_cg: %7.4f, Dz_cg: %7.4f\n\n",M_m_cg,M_m_rp,M_m_aero,M_m_engine,M_m_gear,Dx_cg,Dz_cg); fprintf(out,"%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,",time,V_true_kts,Theta*RAD_TO_DEG,Alpha*RAD_TO_DEG,Q_body*RAD_TO_DEG,Alpha_dot*RAD_TO_DEG,Q_dot_body*RAD_TO_DEG,Throttle_pct,elevator*RAD_TO_DEG); fprintf(out,"%20.8f,%20.8f,%20.8f,%20.8f,%20.8f\n",CL,CLwbh,cm,cd,Altitude); } //begin untrimmed climb at theta_trim + 2 degrees hgain=4; hdiffgain=2; theta_trim=Theta; htarget=theta_trim; herr=Theta-htarget; while(time < tmax) { //ramp in the target theta if(htarget < (theta_trim + 2*DEG_TO_RAD)) { htarget+= 0.01*DEG_TO_RAD; } herrprev=herr; ls_update(1); herr=Theta-htarget; herr_diff=herr-herrprev; Long_control=elev_trim+(hgain*herr + hdiffgain*herr_diff); time+=0.01; //printf("Time: %7.4f, Alt: %7.4f, Alpha: %7.4f, pelev: %7.4f, qdot: %7.4f, udot: %7.4f, Phi: %7.4f, Psi: %7.4f\n",time,Altitude,Alpha*RAD_TO_DEG,Long_control*100,Q_body*RAD_TO_DEG,U_dot_body,Phi,Psi); //printf("Mcg: %7.4f, Mrp: %7.4f, Maero: %7.4f, Meng: %7.4f, Mgear: %7.4f, Dx_cg: %7.4f, Dz_cg: %7.4f\n\n",M_m_cg,M_m_rp,M_m_aero,M_m_engine,M_m_gear,Dx_cg,Dz_cg); fprintf(out,"%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,",time,V_true_kts,Theta*RAD_TO_DEG,Alpha*RAD_TO_DEG,Q_body*RAD_TO_DEG,Alpha_dot*RAD_TO_DEG,Q_dot_body*RAD_TO_DEG,Throttle_pct,elevator*RAD_TO_DEG); fprintf(out,"%20.8f,%20.8f,%20.8f,%20.8f,%20.8f\n",CL,CLwbh,cm,cd,Altitude); } printf("%g,%g\n",theta_trim*RAD_TO_DEG,htarget*RAD_TO_DEG); fclose(out); } void do_takeoff(FILE *out) { SCALAR htarget,hgain,hdiffgain,elev_trim,elev_trim_save,herr; SCALAR time,herrprev,herr_diff; htarget=0; hgain=1; hdiffgain=1; elev_trim=Long_control; elev_trim_save=elev_trim; out=fopen("takeoff.out","w"); herr=Q_body-htarget; // attempt to maintain zero pitch rate during the roll while((V_calibrated_kts < 61) && (time < 30.0)) { // herrprev=herr ls_update(1); // herr=Q_body-htarget; // herr_diff=herr-herrprev; // Long_control=elev_trim+(hgain*herr + hdiffgain*herr_diff); time+=0.01; printf("Time: %7.4f, Vc: %7.4f, Alpha: %7.4f, pelev: %7.4f, qdot: %7.4f, udot: %7.4f, U: %7.4f, W: %7.4f\n",time,V_calibrated_kts,Alpha*RAD_TO_DEG,Long_control*100,Q_body*RAD_TO_DEG,U_dot_body,U_body,W_body); // printf("Mcg: %7.4f, Mrp: %7.4f, Maero: %7.4f, Meng: %7.4f, Mgear: %7.4f, Dx_cg: %7.4f, Dz_cg: %7.4f\n\n",M_m_cg,M_m_rp,M_m_aero,M_m_engine,M_m_gear,Dx_cg,Dz_cg); // fprintf(out,"%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,",time,V_calibrated_kts,Theta*RAD_TO_DEG,Alpha*RAD_TO_DEG,Q_body*RAD_TO_DEG,Alpha_dot*RAD_TO_DEG,Q_dot_body*RAD_TO_DEG,Throttle_pct,elevator*RAD_TO_DEG); fprintf(out,"%20.8f,%20.8f,%20.8f,%20.8f,%20.8f\n",CL,CLwbh,cm,cd,Altitude); } //At Vr, ramp in 10% nose up elevator in 0.5 seconds elev_trim_save=0; printf("At Vr, rotate...\n"); while((Q_body < 3.0*RAD_TO_DEG) && (time < 30.0)) { Long_control-=0.01; ls_update(1); printf("Time: %7.4f, Vc: %7.4f, Alpha: %7.4f, pelev: %7.4f, q: %7.4f, cm: %7.4f, U: %7.4f, W: %7.4f\n",time,V_calibrated_kts,Alpha*RAD_TO_DEG,Long_control*100,Q_body*RAD_TO_DEG,cm,U_body,W_body); fprintf(out,"%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,",time,V_calibrated_kts,Theta*RAD_TO_DEG,Alpha*RAD_TO_DEG,Q_body*RAD_TO_DEG,Alpha_dot*RAD_TO_DEG,Q_dot_body*RAD_TO_DEG,Throttle_pct,elevator*RAD_TO_DEG); fprintf(out,"%20.8f,%20.8f,%20.8f,%20.8f,%20.8f\n",CL,CLwbh,cm,cd,Altitude); time +=0.01; } //Maintain 15 degrees theta for the climbout htarget=15*DEG_TO_RAD; herr=Theta-htarget; hgain=10; hdiffgain=1; elev_trim=Long_control; while(time < 30.0) { herrprev=herr; ls_update(1); herr=Theta-htarget; herr_diff=herr-herrprev; Long_control=elev_trim+(hgain*herr + hdiffgain*herr_diff); time+=0.01; printf("Time: %7.4f, Alt: %7.4f, Speed: %7.4f, Theta: %7.4f\n",time,Altitude,V_calibrated_kts,Theta*RAD_TO_DEG); fprintf(out,"%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,%20.8f,",time,V_calibrated_kts,Theta*RAD_TO_DEG,Alpha*RAD_TO_DEG,Q_body*RAD_TO_DEG,Alpha_dot*RAD_TO_DEG,Q_dot_body*RAD_TO_DEG,Throttle_pct,elevator*RAD_TO_DEG); fprintf(out,"%20.8f,%20.8f,%20.8f,%20.8f,%20.8f\n",CL,CLwbh,cm,cd,Altitude); } fclose(out); printf("Speed: %7.4f, Alt: %7.4f, Alpha: %7.4f, pelev: %7.4f, q: %7.4f, udot: %7.4f\n",V_true_kts,Altitude,Alpha*RAD_TO_DEG,Long_control,Q_body*RAD_TO_DEG,U_dot_body); printf("F_down_total: %7.4f, F_Z_aero: %7.4f, F_X: %7.4f, M_m_cg: %7.4f\n\n",F_down+Mass*Gravity,F_Z_aero,F_X,M_m_cg); } */