Import Symbolic Math Toolbox Equations

When designing a Simscape™ language component, you can use Symbolic Math Toolbox™ software to solve the physical equations and generate code in the format appropriate for the Simscape language equation section. Then, import the results by copying and pasting them into the equation section of a component file and declaring all the symbolic variables used in these equations.

Suppose, you want to generate a Simscape equation from the solution of the following ordinary differential equation. As a first step, use the dsolve function to solve the equation:

syms a y(t)
Dy = diff(y);
s = dsolve(diff(y, 2) == -a^2*y, y(0) == 1, Dy(pi/a) == 0);
s = simplify(s)

The solution is:

s =
cos(a*t)

Then, use the simscapeEquation function to rewrite the solution in the Simscape language equation format:

simscapeEquation(s)

simscapeEquation generates the following code:

ans =
s == cos(a*time);

Copy and paste the generated code into the equation section of a component file:

component MyComponent
  
  equations
        s == cos(a*time);  
  end
end

Make sure the declaration section of the component file contains all the symbolic variables used in these equations. You can declare these symbolic variables as Simscape language variables, parameters, inputs, or outputs, depending on their physical function and your intended block design.

component MyComponent
  inputs
    a = {1,'m/s'};  
  end
  outputs
    s = {0,'m'}; 
  end
  equations
        s == cos(a*time);  
  end
end

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