Index exceeds the number of array elements (1)
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Hello,
I'm implementing NMPC for the control of quadcopter. minimal_example is the script which calls nmpc. u is the control vector of 4 variables, x is a state vector of 12 variables. Dynamic equations (second order system) are described in mathmodel function. During the simulation it shows the error:
Index exceeds the number of array elements (1).
Error in minimal_example>mathmodel (line 82)
xdot = [x(2);
Can anyone suggest how can I fix it? Thank you in advance!
function xdot = mathmodel(t, p, x, u, T)
xdot = [x(2);
(x(4)*x(6)*(p.Iyy-p.Izz)-(u(1)+u(2)+u(3)+u(4))*p.IR*x(4)...
+(p.b*p.l*(u(2)^2-u(4)^2)))/p.Ixx; %phi_dot
x(4); %theta
(x(2)*x(6)*(p.Izz-p.Ixx)+(u(1)+u(2)+u(3)+u(4))*p.IR*x(2)...
+(p.b*p.l*(u(3)^2-u(1)^2)))/p.Iyy; %theta_dot
x(6); %ksi
(x(4)*x(2)*(p.Ixx-p.Iyy)+(p.d*(u(1)^2+u(3)^2-u(2)^2-u(4)^2)))/p.Izz; %ksi_dot
x(8); %X
((p.b*(u(1)^2+u(2)^2+u(3)^2+u(4)^2))*(sin(x(1))*sin(x(5))...
+cos(x(1))*sin(x(3))*cos(x(5))))/p.mass; %X_dot
x(10); %Y
((p.b*(u(1)^2+u(2)^2+u(3)^2+u(4)^2))*(cos(x(1))*sin(x(3))*sin(x(5))...
-sin(x(1))*cos(x(5))))/p.mass; %Y_dot
x(12); %Z
((p.b*(u(1)^2+u(2)^2+u(3)^2+u(4)^2))*(cos(x(1))*cos(x(3)))-p.mass*p.g)/p.mass]'; %Z_dot
end
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Accepted Answer
Jim Riggs
on 25 Jun 2019
Edited: Jim Riggs
on 25 Jun 2019
In the calculation of xdot I see subscripted references for x (up to 12) and u (up to 4).
You should check the size of x and u in the function that is calling "mathmodel" and make sure that x and u have the propper dimensions -> x(12) and u(4)
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