US 5,406,496 AGranted

Adaptive digital controller with automatic plant tuning

AssigneeRecon/Optical, Inc.

InventorJames P. Quinn

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Abstract

The present invention is a method and an apparatus for automatically tuning a plant. The method includes the steps of applying a plurality of sinusoidal signals to the plant, and measuring the frequency response of the plant to the plurality of sinusoidal signals to detect frequencies at which the plant is resonant. The coefficients of at least one digital filter are calculated such that the at least one filter when combined with the plant suppresses the detected resonances. The method further includes applying at least one sinusoidal signal having a frequency substantially equal to a crossover frequency of the system to the at least one filter and plant, and measuring the frequency response to calculate the magnitude and phase response of the filters and plant at that frequency. The coefficients of the compensator are calculated such that when combined with the plant and the at least one filter the combination provides a response which yields said predetermined system response. An apparatus to substantially perform the method as described is also disclosed.

Claims21

Dependent claims

A method of automatically tuning a plant adapted to be controlled by one or more digital filters and a compensator, said plant within a system expected to operate according to a predetermined performance specification, said system having a crossover frequency, said method comprising, in combination, the steps of:

applying a plurality of plant text test signals to said plant;
measuring the frequency response of said plant to said plurality of plant test signals and detecting resonant frequencies of the plant;
adjusting said one or more digital filters by calculating and implementing coefficients of said one or more digital filters such that when said one or more digital filters are combined with said plant, said one or more digital filters suppress the detected resonant frequencies;
applying a compensator test signal to said one or more digital filters and said plant wherein said compensator test signal has a frequency substantially equal to said crossover frequency;
measuring the magnitude and phase response of said one or more digital filters and said plant at said frequency substantially equal to the crossover frequency;
and
adjusting the phase and gain of said compensator in response to said measured magnitude and phase response of said one or more digital filters and said plant at said frequency substantially equal to said crossover frequency, said step of adjusting comprising the step of calculating and implementing coefficients of said compensator such that, when said compensator is combined with said one or more digital filters and said plant, the combination has a frequency response consistent with said predetermined performance specification.

4 more elements

A digital control system for automatically tuning a plant, said plant within a system expected to operate according to a predetermined performance specification, said digital control system comprising:

one or more digital filters;
a compensator;
plant identification means for characterizing the frequency response of said plant within a predetermined bandwidth, said plant identification means comprising,
signal generation means for generating and applying a plurality of plant test signals to said plant,
plant spectrum characterization means for determining the frequency response of said plant to said plurality of plant test signals, and resonance detection means for detecting resonances of said plant;
filter design means for determining and implementing coefficients of said one or more digital filters enabling suppression of the detected resonances;
and
compensator design means for calculating and implementing the coefficients of said compensator including,
input signal generation means for generating and applying a compensator test signal to said one or more digital filters and said plant wherein said compensator test signal is characterized by having a frequency substantially equal to the crossover frequency of said system,
response measuring means for measuring the frequency response of said one or more digital filters and said plant at said crossover frequency, and
compensator calculating means for calculating and implementing coefficients of said compensator based on the frequency response of the response measuring means characterized in that when said compensator is combined with said one or more digital filters and said plant, the combination has said frequency response consistent with said predetermined performance specification.

8 more elements

Dependencies are inferred from the claim text.