Theory 45/Precision & Information/Control systems
Control Stability Is Precision
The claim
The stability of a feedback controller is set by the ratio of sensor precision to loop gain, so a higher-gain controller can be less stable with a noisier sensor.
01Mechanism
Noise passes through the loop and is amplified by gain; beyond a ratio, the controller chases noise instead of the set point.
02Prediction
Stability should fall as precision falls at fixed gain.
03Refutation
Stability tracking gain alone would remove the precision term.