MATLAB: How do i transfer big symbolic equations into Simulink

simulinksymbolic varialbles

Hello everyone,
I am trying to solve the dynamics of a serial manipulator with 6DOF, and I want to transfer the result of an m file (vector of symbolic Torques) into a Simulink block and replace the symbolic variables with a vector of input to have the final numeric result as an output of the block.
I tried a Matlab function block but it does not support symbolic variables.
I tried to call the function as an extrinsic function but Simulink crashes every time I run it.
"from workspace" and "from m file" blocks are not what I need since I have an input to the block.
Any suggestions?
Thanks in advance.

Best Answer

What do you mean by "matlab function does not support symbols"? Maybe I misunderstood your problem, but there is a function called matlabFunction, and it is specifically made to take symbolic expressions and turn them into "numerical functions".
Here is a small example for a 3DOF robot arm:
% Given: symbolic EoM dx = f(....)
syms q1 q2 q3 dq1 dq2 dq3 T1 T2 T3 real
q = [q1 q2 q3]';      % generalized coordinates
dq = [dq1 dq2 dq3]';  % derivative of generalized coordinates
T = [T1 T2 T3]';      % torque vector
% ... HERE: computation of EoM, returning symbolic dx = f(q,dq,T)
% now generate function
matlabFunction(dx,'file','f_dyn','vars',{[q;dq],T});
This will generate a file f_dyn.m with function
function dx = f_dyn(in1,in2)
where in1 = [ q ; dq ] and in2 = T
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