What is Feedforward Control?
Feedforward control is a system design strategy where disturbances are measured and compensated for *before* they can impact the system's output. Unlike feedback control, which reacts to errors after they occur, feedforward control aims to prevent errors by taking preemptive action based on anticipated changes.
How it Works: Key Principles
The core principle involves a disturbance sensor that measures an incoming disturbance and a controller that calculates the necessary corrective action. This action is then applied to the system's input, ideally canceling out the effect of the disturbance. It requires accurate models of the system and the disturbance's effect to be effective.
Practical Example: Cruise Control in a Car
Imagine a car with cruise control encountering an uphill slope. A purely feedback-based system would wait for the car's speed to drop before increasing throttle. A feedforward component, however, could detect the incline (e.g., using a tilt sensor or GPS elevation data) and preemptively increase the throttle *before* the speed noticeably decreases, maintaining a more consistent speed.
Importance and Applications
Feedforward control is crucial in applications where precise regulation is needed, and disturbances are predictable or measurable. It significantly improves transient response, stability, and disturbance rejection, leading to higher performance and efficiency in fields like chemical processing, robotics, aerospace, and even biological regulation.