Editing Feed-forward

Feed-forward is a term describing an element or pathway within a control system which passes a controlling signal from a source in its external environment, often a [[setpoint signal]] from an external operator, to a load elsewhere in its external environment. A control system which has only feed-forward behavior responds to its control signal in a pre-defined way without responding to how the load reacts; it is in contrast with a system that also has feedback, which adjusts the output to take account of how it affects the load, and how the load itself may vary unpredictably; the load is considered to belong to the external environment of the system.

In a feed-forward system, the control variable adjustment is not error-based. Instead it is based on knowledge about the process in the form of a mathematical model of the process and knowledge about or measurements of the process disturbances". For instance such knowledge may be the known inertia (mass) and friction of the system.

Source Wikipedia: [http://en.wikipedia.org/wiki/Feed_forward_(control) Feed forward (control)]