Feedforward control
Acting on a measured disturbance directly, rather than waiting for the process to respond to it.
What it means
Feedforward control measures a disturbance and compensates for it directly, before the process has had a chance to react. Where feedback waits for the process variable to move, feedforward moves the output based on what is coming at the loop.
It earns its place wherever the disturbance is measurable and its effect on the process is predictable. The boiler drum is the classic example: when the steam demand jumps, feedforward opens the feedwater valve on the measurement of the disturbance itself, instead of waiting for the level to fall and asking feedback to catch up afterwards.
Feedforward is a belief about the process, which is both its strength and its weakness. A feedback loop asks nothing of the process except that it eventually respond; feedforward is wrong the moment the real disturbance differs from the one it was calibrated for. In practice the two are combined — feedforward carries the load, and feedback trims the residual error.
Related
Where this comes up
Last reviewed 2026-09-18.