Dynamic system using ode45

Hi,

I need to solve the following function:

function X2d = dynamics(h,theta,beta,hd,thetad,betad,Mt,Ct,Kt,hdd,thetadd,betadd)

X = [h;theta;beta;hd;thetad;betad;hdd;thetadd;betadd];

h = X(1);

theta = X(2);

beta = X(3);

hd = X(4);

thetad = X(5);

betad = X(6);

hdd = X(7);

thetadd = X(8);

betadd = X(9);

X1 = [X(1);X(2);X(3)];

X2 = [X(4);X(5);X(6)];

X2d = [X(7);X(8);X(9)];

X2d = inv(Mt)*(-Ct*X2-Kt*X1);

end

Where d are dot, so it is a system of differential equations.

How can I solve this? May I use ode45?

Thanks

Answer 1

[Muthu]

You first need to convert this function into a form, which can be passed in ode45

To solve using ode45, you need to have three important inputs -> @equation, timerange, initial condition, options

https://nl.mathworks.com/help/matlab/ref/ode45.html

hence your equation should begin like:

function X2d = dynamics(t, Y, options):

Y contains all the initial conditions of the variables.

options contain the arguements that you might need to pass in.

define the constants inside the function.

Then proceed with your code.

Good luck.

[Michelle Westin]

Muthu, thank you for yoour answer. Actually I sumarize the problem to post here. There are other functions to generate the matrices I am using.

I will try to implement like you suggested and if I have another problem, I will post here. Also, I will study a bit more about ode45.

Thank you again and regards