Adaptive digital controller with automatic plant tuning

Claim 3

The method of claim 1 wherein said one or more digital filters comprises one or more notch filters.

Claim 4

The method of claim 1 wherein said coefficients of said at least one or more digital notch filters are calculated using a Tustin transform with prewarp of said detected resonant frequency.

Claim 5

The method of claim 2 wherein said plurality of plant test signals comprise sinusoidal signals having discrete frequencies that are multiples of said crossover frequency.

Claim 6

The method of claim 2 further including the step of calculating the magnitude and phase response of said plant to said plurality of plant test signals.

Claim 7

The method of claim 5 wherein the step of adjustment of said one or more digital filters comprises performing a fast Fourier transform of the response of said plant to said plurality of plant test signals.

Claim 8

The method of claim 2 wherein the step of adjusting the gain and phase of said compensator comprises the step of performing a fast Fourier transform of the response of said plant and said one or more digital notch filters to said compensator test signal.

Claim 9

The method of claim 2 wherein said compensator is a type Proportional-Integral-Differential or a type Proportional-Integral.

Claim 10

The method of claim 1 wherein the step of calculating said coefficients of said compensator includes the step of calculating the phase necessary to provide a desired phase margin of the system and the gain necessary to provide a unity gain at the crossover frequency of the system, and responsively adjusting said compensator according to said calculated necessary gain and phase margin.

Claim 12

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.

Claim 13

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.

Claim 14

The autotuning system of claim 11 wherein said plant spectrum characterization means calculates the magnitude and phase response of said plant by performing a fast Fourier transform of the response of said plant and said plurality of plant test signals.

Claim 15

The autotuning system of claim 11 wherein said one or more digital filters comprises one or more digital notch filters.

Claim 16

The autotuning system of claim 13 wherein said compensator calculating means calculates the magnitude and phase response of said plant and said one or more digital notch filters by performing a fast Fourier transform of the response of said plant and said one or more notch filters to said compensator signal.

Claim 17

The method of claim 13 wherein said compensator is a type Proportional-Integral-Differential or a Proportional-Integral.

Claim 18

The autotuning system of claim 13 wherein said plurality of plant test signals comprise sinusoidal signals having frequencies that are multiples of said crossover frequency.

Claim 19

The autotuning system of claim 16 wherein said calculation of the magnitude and phase response of said plant to said plurality of plant test signals includes performing a fast Fourier transform of the response of said plant to said plurality of plant test signals.

Claim 20

The autotuning system of any one of claims 11, 12, 14, 16 or 17 wherein said plant test signals are sinusoidal signals and wherein said compensator test signal is a sinusoidal signal.

Claim 21

The method of claim 1, wherein said system comprises an aerial reconnaissance camera system.

Claim 22

The method of claim 1, wherein said system comprises a stabilized platform for a sensor.

Claim 23

The method of claim 19 or claim 20, wherein said plant comprises an inertial rate sensor.