Why Closed-Loop Control Oscillates
When a control system first becomes closed loop, the first problem is often not “it does not move.” It is “it keeps moving back and forth.”
Temperature overshoots and undershoots. Motor speed swings around the target. Liquid level control keeps opening and closing a valve. Pressure rises too high, then falls too low. Smaller parameters make the response too slow. Larger parameters make it oscillate.
It is easy to summarize this as: the PID is not tuned well.
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