Feedforwardohjaus

Feedforwardohjaus, also known as predictive control or open-loop control, is a control system strategy that aims to compensate for known disturbances in a process. Unlike feedback control, which relies on measuring the output and correcting errors, feedforward control anticipates the effect of a disturbance based on a model of the system and adjusts the control input proactively.

The core principle of feedforward control is to measure an external variable that is known to affect the system's output and use this measurement to adjust the control signal before the disturbance has an impact. For example, in a heating system, if the outside temperature is a known disturbance, a feedforward controller would measure the outside temperature and adjust the heating output accordingly, even before the room temperature changes significantly.

Feedforward control is often used in conjunction with feedback control. Feedback control handles unmeasured disturbances and ensures the system reaches its setpoint, while feedforward control deals with the predictable, measured disturbances. This combination can lead to faster response times and improved stability compared to using feedback control alone, especially when disturbances are significant or the system is slow to respond.

The effectiveness of feedforward control depends heavily on the accuracy of the system model and the precision of the disturbance measurement. If the model is inaccurate or the disturbance is not measured correctly, the feedforward compensation may be incorrect, leading to deviations from the desired output. Despite these limitations, feedforward control is a valuable tool for improving the performance of many industrial and engineering systems.