Closed-loop control device with adaptive fault compensation

A closed-loop control method for a system to be controlled, wherein the system to be controlled comprises a front node, a back node, an external tapping point arranged between the front and the back node, a controller, a compensating circuit, a measuring device and a setting device, and the compensating circuit comprises an inner node, a frequency filter, a front buffer and a back buffer, said closed-loop control method comprising:

• the front node receiving an actual value detected at an output of the system to be controlled by means of the measuring device, and a corresponding desired value,
• the front node determining a control difference from the difference between the actual value and the corresponding desired value,
• the back node receiving the control difference and a compensation signal,
• the back node supplying the controller with an external sum signal formed by adding the control difference and the compensation signal,
• using the external sum signal, the controller determining a control signal for the system to be controlled
• the controller outputting the control signal to the system to be controlled,
• the inner node determining an internal sum signal by adding the control difference tapped at the external tapping point and weighted with a first weighting factor, and a feedback signal weighted with a second weighting factor,
• the inner node supplying the internal sum signal to the frequency filter,
• the frequency filter carrying out a frequency filtering,
• the frequency filter supplying an output filtered signal to the front buffer,
• the front buffer delaying the output filtered signal by a first propagation delay,
• the front buffer outputting a correspondingly first delayed signal as an output signal,
• the back buffer delaying the compensation signal by a second propagation delay,
• the back buffer outputting a correspondingly second delayed signal as a feedback signal,
• during normal operation of the closed-loop control method, using the output signal of the front buffer as the compensation signal,
• while in a setting mode of the closed-loop control method, the setting device automatically
• suppressing use of the output signal of the front buffer as the compensation signal,
• supplying the back buffer and the back node with a first excitation signal as the compensation signal instead,
• detecting a first result signal produced by the first excitation signal,
• selecting the first result signal from the group consisting of the control difference, the internal sum signal, the output filtered signal of the frequency filter and the output signal of the front buffer, and
• based on an evaluation of the first excitation signal and the first result signal, setting a parameter of the frequency filter and the second propagation delay.