Though simple, this “open loop” form of fan control has disadvantages. Since there is no feedback mechanism, speed accuracy depends entirely on mechanical tolerances of the fan. Although it may not ...

Closed-loop systems do not have this shortcoming. Disturbances in the closed-loop setups are compensated for by measuring the output response and comparing it to the input (feedback).

Over 150 years ago, one of the first attempts to thoroughly describe control loops using feedback took place in James Clark Maxwell’s article, On Governors. 1 In control strategies, an open-loop ...

For most closed-loop feedback control systems, phase margin is greater than 45° (less than 315°) when the loop gain is greater than 0 dB. Gain margin is -20 dB or lower when the loop phase delay ...

And though real-world experimentation on this area has been ongoing for years, a major breakthrough has recently occurred—and at its core is the control feedback loop. “In the body, the autonomic ...