Control system for sheetmaking
AssigneeMeasurex Corporation
InventorsRamesh Balakrishnan, George M. Butler
Life of this patent
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Abstract
A time delay compensation control system for use in controlling a sheetmaking process includes a controller operated according to the Smith Predictor control scheme and means to automatically adjust the closed-loop time constant of the controller in inverse relationship to the system error or to the signal-to-noise ratio of the system output signals.
Claims24
In a system for controlling a sheetmaking process using a time delay compensation control system such as a Smith Predictor control scheme, the improvement comprising:
- adjustment means for automatically varying the closed-loop time constant of the system as a function of the system error.
In a system for controlling a sheetmaking process using a time delay compensation control system such as a Smith Predictor control scheme, the improvement comprising:
- adjustment means to automatically adjust the closed-loop time constant of the system as a function of the signal-to-noise ratio of signals related to the output signals of the control system.
A control system for controlling a sheetmaking process comprising:
- a time delay compensation control system employing a Smith Predictor control scheme;
- system error measurement means for measuring the magnitude, E.sub.i, of the difference between output signals from the control system and preselected reference input signals;
- adjustment means to automatically vary the closed-loop time constant of the system as a function of the system error such that the closed-loop time constant .alpha..sub.i is determined substantially according to the following functional relationship:
- ##EQU4## where E.sub.nom is the nominal error of the system and T.sub.c is the open-loop time constant for the system and where E.sub.nom is determined by the standard deviation of the system error signals.
A control system for controlling a sheetmaking process comprising:
- a time delay compensation control system according to the Dahlin design having the following transfer function, k, for discrete signals, z:
- ##EQU5## where T designates time and .lambda. designates the inverse of the closed-loop time constant .alpha.;
- and
- adjustment means for automatically varying the closed-loop time constant of the system as a function of the system error.
In a system for controlling a sheetmaking process using a time delay compensation control system such as a Smith Predictor control scheme, the improvement comprising adjustment means to automatically adjust the closed-loop time constant of the system such that the closed-loop time constant is related inversely to the signal-to-noise ratio of signals related to the output signals.
In a system for controlling a sheetmaking process using a time delay compression control system according to the Dahlin design, the improvement comprising adjustment means to automatically adjust the closed-loop time constant of the system as a function of the signal-to-noise ratio of signals related to the output signals of the control system, with the time delay compensation control system having the following transfer function in the case of discrete signals:
- ##EQU7## where T designates time and .lambda. designates the inverse of the closed-loop time constant .alpha.;
- and
- adjustment means for automatically varying the closed-loop time constant of the system as a function of the system error.
In a system for controlling a sheetmaking process using a time delay compensation control system such as a Smith Predictor control scheme, the improvement comprising:
- adjustment means to automatically adjust the closed-loop time constant of the system as a function of the signal-to-noise ratio of signals related to the output signals of the control system, and the time delay compensation control system having a transfer function substantially as follows:
- ##EQU8## where G.sub.m represents a preselected model of the plant dynamics, T.sub.m represents a model of the plant time delay, and C represents the controller in the control system.
A system for controlling a continuous sheetmaking machine comprising:
- a time delay compensation control system;
- adjustment means to automatically adjust the closed-loop time constant of the time delay compensation control system such that the closed-loop time constant is related inversely to the signal-to-noise ratio of the output signals.
A system for controlling a continuous sheetmaking machine comprising:
- a time delay compensation control system;
- and
- adjustment means to automatically adjust the closed-loop time constant of the time delay compensation control system as a function of the ratio of low-frequency to high-frequency components in the actuator signals.
A system for controlling a continuous sheetmaking machine comprising:
- a time delay compensation control system;
- and
- adjustment means to automatically adjust the closed-loop time constant of the time delay compensation control system as a function related inversely to the system error.
A system for controlling a continuous sheetmaking machine comprising:
- a time delay compensation control system;
- and
- adjustment means to automatically adjust the closed-loop time constant, .alpha., of the time delay compensation control system as a function of system error, the adjustment means including summing means that provide input error signals E.sub.i to the adjustment means equal to the difference between the output signals from the control system and preselected reference input signals.
In a system for controlling a sheetmaking process using a time delay compensation control system such as a Smith Predictor control scheme, the improvement comprising:
- adjustment means to automatically vary the closed-loop time constant .alpha. of the system according to the following functional relationship:
- ##EQU10## where E.sub.nom is the nominal error of the system, T.sub.c is the open-loop time constant for the system, and E.sub.i is the system error as measured by the magnitude of the difference between the control system output signals and preselected reference input signals.
A system for controlling a continuous sheetmaking machine comprising:
- a time delay compensation control system;
- and
- adjustment means to automatically adjust the closed-loop time constant, .alpha., of the time delay compensation control system as a function of system error, the adjustment means including summing means that provide input error signals E.sub.i to the adjustment means equal to the difference between the output signals from the control system and preselected reference input signals, with the adjustment means operating such that the closed-loop time constant .alpha..sub.i is determined according to the following functional relationship:
- ##EQU11## where E.sub.nom is the nominal error of the system and T.sub.c is the open-loop time constant for the system.
Dependencies are inferred from the claim text.