Hi James,
The error message that you are facing is caused by the below line:
M = [m1*lc1^2+m2(l1^2+lc2^2+2*l1+lc2*cos(q2))+I1+I2, m2(lc2^2+l1*lc2*cos(q2));m2lc2^2+l1*lc2*cos(q2)+I2, m2lc2^2+I2];
As m2 is defined as a scalar in the script, using indexing in the following way "m2(l1^2+lc2^2+2*l1+lc2*cos(q2))" is not supported.
There are a few more syntax errors that I obsereved in the code provided. Below is the code after correcting the syntax errors with the comments explaining the changes.
function[sys,x0,str,ts] = Dynamique2DOF(t,x,u,flag)
m1=9.5; m2=5;
l1=0.25; l2=0.16;
lc1=0.20;lc2=0.14;
I1=4.3*10^(-3); I2=6.1*10^(-3);
g=9.8;
q2=1;
%providing a temporary definition for M, C and G
M = [1, 2; 3, 4]
C = [1, 2; 3, 4]
G = [1, 2; 3, 4]
%M = [m1*lc1^2+m2(l1^2+lc2^2+2*l1+lc2*cos(q2))+I1+I2, m2(lc2^2+l1*lc2*cos(q2));m2lc2^2+l1*lc2*cos(q2)+I2, m2lc2^2+I2];
%to avoid the error "Subscript indices must either be real positive integers or logicals."
%C = [-m2*l1*lc2*sin(q2)*dq2, -m2*l1*lc2*sin(q2)*(dq1+dq2); m2*l1*lc2*sin(q2)*dq2, 0];
%dq2 is undefined
%G = [(m1*lc1+m2*l1)*g*cos(q1)+m2*lc2*g*cos(q1+q2); m2*lc2*g*cos(q1+q2)];
%q1 is undefined
sys = 0, x0 = 0, str = 0, ts = 0; %these variables must be initialized irrespective of the "flag", as these are returned by the function "Dynamique2DOF"
switch flag %comma is not allowed here
case 0
[sys,x0,str,ts]=mdlInitializeSizes;
case 1
sys = mdlDerivatives(t,x,u);
case 3
sys = mdlOutputs(t,x,u);
case { 2, 4, 9 }
sys = [];
otherwise
error(['Unhandled flag = ',num2str(flag)]);
end
end %ending a function is necessary
function [sys,x0,str,ts]=mdlInitializeSizes
sizes = simsizes;
sizes.NumContStates = 2;
sizes.NumDiscStates = 0;
sizes.NumOutputs = 4;
sizes.NumInputs = 2;
sizes.DirFeedthrough = 0;
sizes.NumSampleTimes = 1;
sys=simsizes(sizes);
x0=[1 0.8 0 0];
str=[];
ts=[1 0];
end %ending a function is necessary
function sys=mdlDerivatives(t,x,u) %semicolon is not allowed here
dq1 = q2;
dq2 = (tau - C*dq2 + G)/M;
sys(1)=dq1;
sys(2)=dq2;
sys(3)=ddq1;
sys(4)=ddq2;
end %ending a function is necessary
function sys=mdlOutputs(t,x,u)
sys(1)=q1;
sys(2)=q2;
sys(3)=q3;
sys(4)=q4;
end %ending a function is necessary
Hope this helps!
