Which control strategy is used to anticipate disturbances before the process output changes?

Which control strategy is used to anticipate disturbances before the process output changes?

• A. Feedback control
• B. Proportional control
• C. Predictive control
• D. Feedforward control

Answer: (D)

Anticipating disturbances before the output changes relies on acting on information about the disturbance itself to offset its effect preemptively. Feedforward control does exactly this: it measures or estimates a disturbance and adjusts the manipulated variable before the process output deviates, keeping the setpoint on track. This proactive approach is what distinguishes it from reactive methods. For example, if a feed concentration is known to change, the feedforward controller can adjust valves or flow rates to counter that change before the process responds. In contrast, feedback control waits for an error to appear and then corrects it, and a simple proportional law is just a basic form of this reactive strategy. Predictive control uses a model to forecast future behavior and optimize actions, but the core idea of anticipating a disturbance through measurement or estimation aligns most directly with feedforward control.

Anticipating disturbances before the output changes relies on acting on information about the disturbance itself to offset its effect preemptively. Feedforward control does exactly this: it measures or estimates a disturbance and adjusts the manipulated variable before the process output deviates, keeping the setpoint on track. This proactive approach is what distinguishes it from reactive methods. For example, if a feed concentration is known to change, the feedforward controller can adjust valves or flow rates to counter that change before the process responds. In contrast, feedback control waits for an error to appear and then corrects it, and a simple proportional law is just a basic form of this reactive strategy. Predictive control uses a model to forecast future behavior and optimize actions, but the core idea of anticipating a disturbance through measurement or estimation aligns most directly with feedforward control.