ODE45 How to use atmosisa function with Height function as Input?

Hello,

I need help to configure how to use atmosisa function if we need to use height function h(t) as input? In this ODE45, I set variable z to be z(1), z(2), z(3) and z(4). z(2) is the height variable. When I put height to be 1000m, the code does work but when I put in as z(2) as input, it gives error.

Density.m

function rho=density()
[~, ~, ~, rho]=atmosisa(z(2));
end

rhs_trajectory

function dz = rhs_trajectory(z,g,F,F_d,m,gamma)

   x     = z(1);
   y     = z(2);
   v_x   = z(3);
   v_y   = z(4); 

   dx     = v_x;
   dy     = v_y;
   dv_x   = ((F-F_d)/m)*cos(gamma)-m*sin(gamma);
   dv_y   = ((F-F_d)/m)*sin(gamma)-g;

   dz     = [dx; dy; dv_x; dv_y];

end

I attached other necessery function for reference. Please help me.

[darova]

The question is unclear

• You are passing some argument into atmosisa, but not passing into density

function rho=density()  % z(2) should an argument
[~, ~, ~, rho]=atmosisa(z(2));
end

• i don't see you use density function. Where do you want to use it?

Answer 1

[Star Strider]

‘but when I put in as z(2) as input, it gives error’

That is most likely because you do not pass it as an argument to your ‘density’ function.

Try this:

function rho=density(x)
[~, ~, ~, rho]=atmosisa(x);
end

(I also do not see where you called it in your ‘rhs_trajectory’ function.)

I do not have the Aerospace Toolbox, so I cannot test this directly. However the problem appears to be obvious.