Question

A feedforward controller can be used only if:

• A. the disturbance variable can be measured
• B. the disturbance variable can be manipulated
• C. the disturbance variable can be ignored
• D. regulatory control is not required

Hint:

Feedforward control = disturbance must be measurable.

Answer 1

The Correct Option is A

Feedforward control works by measuring disturbances before they affect the process and adjusting the control action proactively.

Step 1: Understand feedforward control.
It is a proactive control strategy that requires real-time measurement of the disturbance variable. Without knowing the disturbance value, the controller cannot compute the compensatory action.

Step 2: Evaluate options.
- (A) Correct — feedforward requires measurable disturbances.
- (B) Manipulating the disturbance is not part of feedforward strategy.
- (C) Ignoring disturbances defeats the purpose of feedforward control.
- (D) Regulatory control is often still required; feedforward is used in combination with feedback.
Conclusion: Only option (A) captures the requirement for feedforward control.