Which term in a PID controller helps reduce overshoot and dampen oscillations?

• A. The proportional term helps reduce overshoot and dampen oscillations.
• B. The derivative term helps reduce overshoot and dampen oscillations.
• C. The integral term does that.
• D. The derivative term increases overshoot.

Answer: (B)

The derivative term acts on how fast the error is changing, serving as a damper for the system. By responding to the rate at which the error approaches the setpoint, it adds a corrective action that slows down rapid movements as the error grows, which reduces the tendency to overshoot. This damping effect also helps smooth out rapid fluctuations, lowering oscillations in the response.

In contrast, the proportional term mainly sets the immediate correction proportional to the current error and can contribute to overshoot if too aggressive. The integral term addresses persistent, steady-state error but can introduce overshoot and longer settling time if used aggressively. The derivative term, when tuned properly, provides the damping needed to keep the response stable and less oscillatory. Note that it can be sensitive to noise, so some filtering is often used.