styrutslag

Styrutslag, a term used in Swedish and Norwegian control engineering, refers to the excursion or swing in a controlled variable or in the actuator signal caused by a disturbance or by the controller’s action. It describes how far the manipulated variable deviates from its desired reference during transient responses.

Measuring styrutslag typically involves the peak deviation or the peak-to-peak amplitude of the control signal or the controlled process variable as it moves from its setpoint. It is influenced by factors such as disturbances, actuator saturation, time delays, and the tuning of the control loop, including the gains and the presence of integral action.

In practice, styrutslag is a key aspect of system performance. A small styrutslag can indicate a smooth response, but overly aggressive tuning that minimizes deviation can lead to instability, excessive wear, or actuator saturation. Conversely, a large styrutslag may reflect underdamped or aggressive control, resulting in higher stress on actuators and potential safety concerns. Anti-windup mechanisms are often employed to limit excursions when actuators saturate.

Styrutslag is closely related to concepts such as overshoot, undershoot, settling time, and robustness. Engineers aim to balance a quick, accurate response with limits imposed by actuators and safety requirements, thereby minimizing unwanted excursions while preserving stable operation.