You can only control a inverted pendulum using a PID if it's near one of its equilibrium points. You need a linearized model of the dynamics and this is usually

You can only control a inverted pendulum using a PID if it's near one of its equilibrium points. You need a linearized model of the dynamics and this is usually done using the small angle aproximation for the sine. I don't think they are using a PID controller for the pendulum in that video.