I didn't realize that to model a set of governing differential equations of a dynamical system in Simulink will require some modifications on the original equations of motion. Here is what I am confused about:
I'm following a tutorial to build a simulink model on inverted pendulum:
At first, the GDE of the system is described as follows:
Then, when the GDE is embedded into the Simulink model, some modifications are made:
When I rearrange and isolate x_dot_dot and theta_dot_dot in the original GDE, I get something different from the new GDE used in the screenshot above. Why is this the case??