Solving this matrix with the correct response using MATLAB and simulink
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this is the given problem.
this is the Simulink and here is the call back for the function command:
here is my code
clc
clear
%---------------EQUATIONS_FROM_FBD------------------------------------------------------------------------------------------------------------------------------------------------
%......................................................................SUM_OF_EXTERNAL_FORCES=M*X"................................................................................
% MfXf"=-Ksf(Xf-[Xb-(L1*theta)})-Bsf(Xf'-{Xb'-(L1*theta')})+(Kf*Xf);
% Vf'=(1/Mf)[(-Ksf(Xf-(L1*theta))-(Bsf(Vf-(L1*theta'))+(Kf*Xf)] ;
% MrXr"=-Ksr(Xr+[Xb+(L2*theta)])-Bsr(Xr'+[Xb'+(L2*theta'))+(Kr*Xr) ;
% Vr'=(1/Mr)[-Ksr(Xr+(L2*theta))-Bsr(Vr+(L2*theta'))+(Kr*Xr)] ;
% MbXb"=Ksf(Xf-[Xb-(L1*theta)])+Bsf(Xf'-[Xb'-(L1*theta')])+Ksr(Xr+[Xb+(L2*theta)])+Bsr(Xr'+[Xb'+(L2*theta'))+fa(t);
% Vb'=(1/Mb)[Ksf(Xf-(L1*theta))+Bsf(Vf-(L1*omega))+Ksr(Xr+(L2*theta))+Bsr(Vr+(L2*omega))+fa(t)];
syms Ksf Xf L1 theta Bsf Vf omega Ksr Bsr Kf Kr Vr Mr Ar Xr L2 Af Ab Mf Mb fa(t) Alpha Ic L3 Xb Vb
z=Mr*Ar==-Ksr*(Xr+(Xb+(L2*theta)))-Bsr*(Vr+(Vb+(L2*omega)))+(Kr*Xr);
expand(solve(z,Ar))
ans =
y=Mf*Af==-Ksf*(Xf-(Xb-(L1*theta)))-Bsf*(Vf-(Vb-(L1*omega)))+(Kf*Xf);
expand(solve(y,Af))
ans =
x=Mb*Ab==Ksf*(Xf-(Xb-(L1*theta)))+Bsf*(Vf-(Vb-(L1*omega)))+Ksr*(Xr+(Xb+(L2*theta)))+Bsr*(Vr+(Vb+(L2*omega)))+fa(t);
expand(solve(x,Ab))
ans =
%.....................................................................SUM_OF_EXTERNAL_TORQUE=J*THETA"...............................................................................................
% Ic*theta"={-[Ksf(Xf-(L1*theta))*L1]-[Bsf(Xf'-(L1*theta'))*L1]+[Ksr(Xr+(L2*theta))*L2]+[Bsr(Xr'+(L2*theta'))*L2]+[fa(t)*L3]};
% omega'=(1/Ic){[-Ksf*Xf + Ksf((L1)^2)*theta)] + [-Bsf*Vf*L1 + Bsf*Vf*L1 + Bsf((L1)^2)*omega)] + [Ksr*Xr*L2 + Ksr((L2)^2)*theta)] + [Bsr*Vr*L2 + Bsr((L2)^2)*omega)*L2] + [fa(t)*L3]};
w=Ic*Alpha==-Ksf*(Xf-(Xb-(L1*theta)))*L1-Bsf*(Vf-(Vb-(L1*omega)))*L1+Ksr*(Xr+(Xb+(L2*theta)))*L2+Bsr*(Vr+(Vb+(L2*omega)))*L2+fa(t)*L3;
expand(solve(w,Alpha))
ans =
%.....................................................................OUTPUT_EQUATIONS..................................................................................................................
syms f_Ksf f_Kf f_Bsf f_Ksr f_Kr f_Bsr
% f_Ksf=Ksf(Xf-(-L1*theta));
% f_Kf=Kf*Xf;
% f_Bsf=Bsf(Vf-(-L1*omega));
% f_Ksr=Ksr(Xr-(L2*theta));
% f_Kr=Kr*Xr;
% f_Bsr=Bsr(Vr-(L2*omega));
f_Ksf=Ksf*(Xf-(Xb-(-L1*theta)));
A=simplify(f_Ksf);
expand(A)
ans =
f_Bsf=Bsf*(Vf-(Vb-(-L1*omega)));
B=simplify(f_Bsf);
expand(B)
ans =
f_Ksr=Ksr*(Xr-(Xb+(L2*theta)));
C=simplify(f_Ksr);
expand(C)
ans =
f_Bsr=Bsr*(Vr-(Vb+(L2*omega)));
D=simplify(f_Bsr);
expand(D)
ans =
% Mb*Vb'-Ksf(Xf-(L1*theta))-Bsf(Xf'-(L1*theta'))-Ksr(Xr+(L2*theta))-Bsr(Xr'+(L2*theta'))=fa(t);
% Ic*omega'+[Ksf(Xf-(L1*theta))*L1]+[Bsf(Vf-(L1*omega))*L1]-[Ksr(Xr+(L2*theta))*L2]-[Bsr(Vr+(L2*omega))*L2]=[fa(t)*L3]
clc
clear
%-------------------------------------------------SYSTEM_PARAMETERS----------------------------------------------------------------------------------------------------------------------------------------------------------
Ic=1356; %kg-m^2
Mb=730; %kg
Mf=59; %kg
Mr=45; %kg
Kf=23000; %N/m
Ksf=18750; %N/m
Kr=16182; %N/m
Ksr=12574; %N/m
Bsf=100; %N*s/m
Bsr=100; %N*s/m
L1=1.45; %m
L2=1.39; %m
L3=0.67; %m
%-------------------------------------------------------------------------------------Matrix's-----------------------------------------------------------------------------------------------------------------------------------
%__________________________________________________INPUT__MATRIX_________________________________________________________________________________________________________________________________________________________________
%________________________________________________________________________________________________________________________________________________________________________________________________________________________________
%......Xf...................Vf......................Xr...................Vr..................Xb...........................Vb................................theta.............................omega..............................
%________________________________________________________________________________________________________________________________________________________________________________________________________________________________
a=[ 0 1 0 0 0 0 0 0; %Xf'
((-Ksf+Kf)/Mf) (Bsf/Mf) 0 0 (Ksf/Mf) (Bsf/Mf) ((Ksf*L1)/Mf) ((Bsf*L1)/Mf); %Vf'
0 0 0 1 0 0 0 0; %Xr'
0 0 ((-Ksr+Kr)/Mr) (-Bsr/Mr) (-Ksr/Mr) (-Bsr/Mr) ((-Ksr*L2)/Mr) ((-Bsr*L2)/Mr); %Vr'
0 0 0 0 0 1 0 0; %Xb'
(Ksf/Mb) (Bsf/Mb) (Ksr/Mb) (Bsr/Mb) ((Ksr-Ksf)/Mb) ((Bsr-Bsf)/Mb) (((-Ksf*L1)+(Ksr*L2))/Mb) (((-Bsf*L1)+(Bsr*L2))/Mb); %Vb'
0 0 0 0 0 0 0 1; %theta'
((-Ksf*L1)/Ic) ((-Bsf*L1)/Ic) ((Ksr*L2)/Ic) ((Bsr*L2)/Ic) (((Ksf*L1)+(Ksr*L2))/Ic) (((Bsf*L1)+(Bsr*L2))/Ic) (((Ksr*(L2^2))+(Ksf*(L1^2)))/Ic) (((Bsr*(L2^2))+(Bsf*(L1^2)))/Ic)]; %omega'
b=[0;
0;
0;
0;
0;
(1/Mb);
0;
((L3)/Ic);];
%________________________________________________OUTPUT__MATRIX_____________________________________________________________________________________________________________________________________________________________________
c=[ (Ksf) 0 0 0 (-Ksf) 0 (-Ksf*L1) 0; %f_Ksf
Kf 0 0 0 0 0 0 0; %f_Kf
0 (Bsf) 0 0 0 (-Bsf) 0 (Bsf*L1); %f_Bsf
0 0 (Ksr) 0 (-Ksr) 0 (-Ksr*L2) 0; %f_Ksr
0 0 Kr 0 0 0 0 0; %f_Kr
0 0 0 (Bsr) 0 (-Bsr) 0 (-Bsr*L2); %f_Bsr
(Ksf/Mb) (Bsf/Mb) (Ksr/Mb) (Bsr/Mb) 0 0 (((-Ksf*L1)+(Ksr*L2))/Mb) (((-Bsf*L1)+(Bsr*L2))/Mb); %Ab
0 0 0 0 (((Ksr*L2)-(Ksf*L1))/Ic) (((Bsr*L2)-(Bsf*L1))/Ic) (((Ksr*(L2^2))-(Ksf*(L1^2)))/Ic) (((Bsr*(L2^2))-(Bsf*(L1^2)))/Ic)]; %ALPHAm
d=[0;
0;
0;
0;
0;
0;
1/Mb;
(L3/Ic)];
CSTR=ss(a,b,c,d)
CSTR =
A =
x1 x2 x3 x4 x5 x6 x7 x8
x1 0 1 0 0 0 0 0 0
x2 72.03 1.695 0 0 317.8 1.695 460.8 2.458
x3 0 0 0 1 0 0 0 0
x4 0 0 80.18 -2.222 -279.4 -2.222 -388.4 -3.089
x5 0 0 0 0 0 1 0 0
x6 25.68 0.137 17.22 0.137 -8.46 0 -13.3 -0.008219
x7 0 0 0 0 0 0 0 1
x8 -20.05 -0.1069 12.89 0.1025 32.94 0.2094 46.99 0.2975
B =
u1
x1 0
x2 0
x3 0
x4 0
x5 0
x6 0.00137
x7 0
x8 0.0004941
C =
x1 x2 x3 x4 x5 x6 x7 x8
y1 1.875e+04 0 0 0 -1.875e+04 0 -2.719e+04 0
y2 2.3e+04 0 0 0 0 0 0 0
y3 0 100 0 0 0 -100 0 145
y4 0 0 1.257e+04 0 -1.257e+04 0 -1.748e+04 0
y5 0 0 1.618e+04 0 0 0 0 0
y6 0 0 0 100 0 -100 0 -139
y7 25.68 0.137 17.22 0.137 0 0 -13.3 -0.008219
y8 0 0 0 0 -7.161 -0.004425 -11.16 -0.01257
D =
u1
y1 0
y2 0
y3 0
y4 0
y5 0
y6 0
y7 0.00137
y8 0.0004941
Continuous-time state-space model.
Model Properties
sys_tf=tf(CSTR);%System transfer function
impulse(sys_tf)
sys_zpg=zpk(CSTR);%system zero pole gain
impulse(sys_zpg)
syms s real;
i=eye(8);
h=simplify(c*inv((s*i)-a)*b+d)
h =
h(1)
ans =
simplify(h(1))
ans =
%-------------------------SIMULATION-----------------------------------------------
sim('Pagels_Jon_Project_Matrix_simulation')
fat=10*(exp(-5*t));
Xf=q(:,1);
Vf=q(:,2);
Xr=q(:,3);
Vr=q(:,4);
Xb=q(:,5);
Vb=q(:,6);
theta=q(:,7);
omega=q(:,8);
%----------------------------FORCES------------------------------------------------
KSF=y(:,1);
KF=y(:,2);
BSF=y(:,3);
KSR=y(:,4);
KR=y(:,5);
BSR=y(:,6);
Ab=y(:,7);
Alpha_m=y(:,8);
%----------------------------FIGURES-------------------------------------------------
figure(1)
set(gcf,'color','white')
subplot(3,1,1);
plot(t,Xb,'-b','linewidth',0.5);grid
title('Displacement of Body Linear vs. Time')
xlabel ('Time (s)') ;
ylabel ('Displacement (m)');
subplot(3,1,2);
plot(t,theta,'-k','linewidth',0.5);grid
title('Displacement of Body Angular vs. Time ')
xlabel ('Time (s)') ;
ylabel ('Displacement (rad)');
subplot(3,1,3);
plot(t,fat,'-m','linewidth',0.5);grid
title('Impulse Force from Road vs. Time')
xlabel ('Time (s)') ;
ylabel ('Force (N/s)');
figure(2)
set(gcf,'color','white')
subplot(3,1,1);
plot(t,Xf,'-c','linewidth',0.5);grid
title('Displacement of Front Axel vs. Time')
xlabel ('Time (s)') ;
ylabel ('Displacement (m)');
subplot(3,1,2);
plot(t,KSF,'-m','linewidth',0.5);grid
hold on
subplot(3,1,2);
plot(t,KF,'-y','linewidth',0.5);grid
title('Front Spring Force vs. Time ')
xlabel ('Time (s)') ;
ylabel ('Spring Force-Front (N)');
hold off
subplot(3,1,3);
plot(t,BSF,'-g','linewidth',0.5);grid
title('Front Damper Force vs. Time')
xlabel ('Time (s)') ;
ylabel ('Damper Force-Front (N/s)');
figure(3)
set(gcf,'color','white')
subplot(3,1,1);
plot(t,Xr,'-c','linewidth',0.5);grid
title('Displacement of Rear Axel vs. Time')
xlabel ('Time (s)') ;
ylabel ('Displacement (m)');
subplot(3,1,2);
plot(t,KSR,'-m','linewidth',0.5);grid
hold on
subplot(3,1,2);
plot(t,KR,'-y','linewidth',0.5);grid
title('Rear Spring Force vs. Time ')
xlabel ('Time (s)') ;
ylabel ('Spring Force-Rear (N)');
hold off
subplot(3,1,3);
plot(t,BSR,'-g','linewidth',0.5);grid
title('Rear Damper Force vs. Time')
xlabel ('Time (s)') ;
ylabel ('Damper Force-Rear (N/s)');
I am not seeing the response in the springs and dampers everything plots as an exponential curve, I'd expect to see some oscilation. I'm not sure if I'm entering something incorrectly.
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