tilstandsvariable
Tilstandsvariable (state variable) is a variable that encodes the internal state of a dynamical system at a given time and, together with the inputs, determines the system’s future behavior. The collection of all such variables forms the state vector x. In modeling, the tilstandsvariable distinguishes what must be known to predict evolution from what is external input or observed output.
In continuous-time models the evolution is described by dx/dt = f(x, u, t) and outputs by y =
Examples include: a pendulum described by angle and angular velocity as state; a vehicle described by position
Importance and applications: the concept underpins controllability and observability, which determine whether a system can be