Problem with solve and syms array to have numerical results

Hello,

I would like to see numerical results, with solve and sims arrays, but it doesn't work. Here is my code. My problem concerns the last lines from "%Inconnues"

clear
clc
close all

% Valeur accélération mm/s², vitesse mm/s, temps total s, position initial rad, position final rad 

a=14.77/2;
v=14.77;
T=12;
X0=0;
XT=pi/2;


a=(a*90/147.7)*(pi/180);
v=(v*90/147.7)*(pi/180);

% vecteur t

t=0:(10^(-1)):T;

% Accélération angulaire A :

A=zeros(1,T*10^(1)+1);
for n=1 : ((v/a)*10^(1)+1)
    A(1,n) = a;
end
for n=(length(t)-round(v/a)*10^(1)) : (length(t))
    A(1,n)= -a;
end

%Vitesse angulaire V :

V=zeros(1,T*10^(1)+1);
for n=1 : (round((v/a)*10^(1))+1)
    V(1,n) = a*t(1,n);
end
for n=(round((v/a)*10^(1))+1+1) : (length(t)-round((v/a)*10^(1))-1)
    V(1,n) = v;
end
for n=(length(t)-round((v/a)*10^(1))) : (length(t))
    V(1,n)= (v+a*t(1,(length(t)-round((v/a)*10^(1))))) -a*t(1,n);
end

%Déplacement angulaire X :
X=zeros(1,T*10^(1)+1);

for n=1 : (round((v/a)*10^(1))+1)
    X(1,n) = a*t(1,n)^(2)/2;
end
for n=(round((v/a)*10^(1))+1+1) : (length(t)-round((v/a)*10^(1))-1)
    X(1,n) = v*t(1,n)-(v^(2)/(2*a));
end
for n=(length(t)-round((v/a)*10^(1))) : (length(t))
    X(1,n)= (v+a*t(1,(length(t)-round((v/a)*10^(1)))))*t(1,n) -(a*t(1,n)^(2)/2)+(XT+(a*T^(2)/2)-(v+a*t(1,(length(t)-round((v/a)*10^(1)))))*T);
end

% Vecteurs OA, OB et OG
Xoa=96*10^(-3);
Yoa=46*10^(-3);
Xob=350*10^(-3);
Yob=23*10^(-3);
Xog=257.69*10^(-3);
Yog=24.53*10^(-3);

% Masse et moment d'inertie
m=24.9;
Iz=2.36;
g=9.81;

%angle Phi

Z=-asin((Xoa*sin(X)+Yoa*cos(X)-Yob)/sqrt(-sin(X)*(2*Xoa*Yob-2*Xob*Yoa)-cos(X)*(2*Xoa*Xob+2*Yoa*Yob)+Xoa^(2)+Xob^(2)+Yoa^(2)+Yob^(2)));

%Inconnues:
X01=sym('X01',[1 121]);
Y01=sym('Y01',[1 121]);
F21=sym('F21',[1 121]);

%Sommes forces et moments
%x
Xf=X01+F21.*cos(Z);

%y
Yf=Y01+F21.*sin(Z)-m*g;

%z
Zf=F21.*sin(Z).*(Xoa.*cos(X)-Yoa.*sin(X))-F21.*cos(X).*(Yoa.*cos(X)+Xoa.*sin(X))-(Xog.*cos(X)-Yog.*sin(X)).*m.*g;

%Torseur dynamique
%x
Xd=-Xog.*(A.*sin(X)+V.^(2).*cos(X))+Yog.*(-A.*cos(X)+V.^(2).*sin(X));

%y
Yd=Xog.*(A.*cos(X)-V.^(2).*sin(X))-Yog.*(A.*sin(X)+V.^(2).*cos(X));

%z
Zd=Iz.*A;

%PFD
eqn1= Xf==Xd;
eqn2= Yf==Yd;
eqn3= Zf==Zd;

sol=solve([eqn1 eqn2 eqn3],[F21 X01 Y01]);

I would like to have the numerical values of F21 X01 and Y01.

I tried with

 double(subs(F21))
 vpa(F21)
 sol=vpasolve([eqn1 eqn2 eqn3],[F21 X01 Y01])

but it didn't work.

If I call F21 it gives me

F21 =
 [F211, F212, F213, F214, F215, F216, --- , F21117, F21118, F21119, F21120, F21121]

>> F21(1,1)
 
ans =
 
F211

If I call sol it gives me

sol = 

  struct with fields:

      F211: [1×1 sym]
      F212: [1×1 sym]
      F213: [1×1 sym]
      F214: [1×1 sym]
      F215: [1×1 sym]
      F216: [1×1 sym]
      F217: [1×1 sym]
     -------------
    Y01116: [1×1 sym]
    Y01117: [1×1 sym]
    Y01118: [1×1 sym]
    Y01119: [1×1 sym]
    Y01120: [1×1 sym]
    Y01121: [1×1 sym]

The only solution that I find to have value is

sol.F211
 
ans =
 
-967.60287385780605423753073081481

but I want all the values and when I do

sol.F21(1,1)

It doesn't work again.

I didn't use matlab for a long time, so it's probably a silly mistake.

Can someone help me please ?

Many thanks in advance for your help.

Answer 1

[Hugo RUNG]

I find the solution of my problem. If someone as the same problem you can try this :

To start, declare all the variables as syms

Then, use solve (equal to something)

After that, you can assign numerical values to the variables.

To finish, evaluate the solutions.

Here is an exemple :

syms X1 Y1 Z1 X2 Y2 Z2 a b c;
eqn1= X1.*Z1==a;
eqn2= Y1-Z2==b;
eqn3= X2./Y2==c;

sol=solve([eqn1 eqn2 eqn3],[a b c])

X1=3;
Y1=-8;
Z1=1:1:1000
.......

a=eval(sol.a)
b=eval(sol.b)
c=eval(sol.c)