Trying to solve linear system of equations into matrix form error

Here is my line of code and looking to put into matrix form Ax=B.

I keep getting the error "Unable to convert to matrix form because the system does not seem to be linear"

Any ideas on how to fix this? I am new to matlab and do not know if it is just syntax.

syms m1 ac1 g rot1x R2 f2 f1 m2 ac2 rot2x R3 f3 f2 a1 l1 w_dot1 l1 w1 a2 l2 w_dot2 w2 a0 l0 w_dot0 w0
eqn1 = (m1 * ac1) - (m1 * g * rot1x) - (R2*f2) == f1;
eqn2 = (m2 * ac2) - (m2 * g * rot2x) + (R3 * f3) == f2;
eqn3 = a1 + (0.5 * l1 * w_dot1) + (0.5 * l1 * w1) == ac1;
eqn4 = a2 + (0.5 * l2 * w_dot2 + 0.5 * l2 * w2) == ac2;
eqn5 = R2 * (a0 + l0 * w_dot0) + (l0 * w0) - a1 == 0; 
eqn6 = R3 * (a1 + l1 * w_dot1) + (l1 * w1) - a2 ==0;


[A,B] = equationsToMatrix([eqn1, eqn2, eqn3, eqn4, eqn5, eqn6]);

Answer 1

[Marco Riani]

% eqns must be linear in vars.

% Specify vars as follows (for example).

vars=[m1, m2, w1, w2, w_dot0,  w_dot1];
[A,B] = equationsToMatrix([eqn1, eqn2, eqn3, eqn4, eqn5, eqn6],vars);

% Of course I do not what are your vars so I tried to guess

[Jack]

hi, I did what you suggested and that seems to have worked to get rid of the error, it is now just not printing the A and B matrices.

[Marco Riani]

Hi, this is what I get when I print A or B

A =

[ac1 - g*rot1x, 0, 0, 0, 0, 0]

[ 0, ac2 - g*rot2x, 0, 0, 0, 0]

[ 0, 0, l1/2, 0, 0, l1/2]

[ 0, 0, 0, l2/2, 0, 0]

[ 0, 0, 0, 0, R2*l0, 0]

[ 0, 0, l1, 0, 0, R3*l1]

B

B =

f1 + R2*f2

f2 - R3*f3

ac1 - a1

ac2 - a2 - (l2*w_dot2)/2

a1 - R2*a0 - l0*w0

a2 - R3*a1

[Jack]

thansks! what system are you working with/ matlab version? maybe that is why mine is not loading.

[Marco Riani]

2020b on windows

[Jack]

thanks for all the help!