Ostyrbar

Ostyrbar is a term used in Swedish-language engineering and control literature to describe systems, processes, or agents that cannot be steered toward a desired state with the available inputs. In English-language writing, ostyrbar is typically translated as uncontrollable or unsteerable. The word is sometimes encountered in discussions of mechanical systems, robotics, and dynamic models to denote a fundamental limitation rather than a temporary failure.

In control theory, a system is controllable if its state can be driven to any other state in finite time with an appropriate control input. If some state directions cannot be reached from a given initial condition using admissible inputs, the system is considered uncontrollable; such a system may be described as ostyrbar. Causes include insufficient actuation, structural constraints, or fixed external disturbances. For linear time-invariant systems, the Kalman controllability criteria provide a practical test: the controllability matrix must have full rank.

Beyond engineering, ostyrbar can be used in science fiction and media to describe devices, vehicles, or autonomous agents that cannot be piloted or redirected once set in motion, whether due to design, external control loss, or emergent behavior.

See also: controllability, open-loop vs closed-loop control, Kalman criterion, dynamic systems.