US 5,726,879 AGranted

Control apparatus, a stage apparatus and a hard disk servo writer apparatus including a robust stabilizing compensator

AssigneeCanon Kabushiki Kaisha

InventorMikio Sato

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Abstract

Provided is high-performance H.sub..infin. control technology suitable for position control or speed control of semiconductor exposure apparatus, servo writer of hard disk, etc. A series compensator in the classical control technology represented by the PID compensator is employed as a frequency weight of loop shaping, whereby the design technology in the conventional classical control can be succeeded to and a high-performance control system can be realized even for cases where there is an oscillation mode of a controlled object to become a problem on control performance in the servo band, which was difficult to realize by the classical control technology. Also, using a robust stabilizing compensator obtained from a generalized plant having constant matrix weights, a high-performance control system can be realized even for cases where there is an oscillation mode of the controlled object to become a problem on control performance in the servo band, which was difficult to realize by the conventional classical control technology.

Claims17

Dependent claims

A control apparatus comprising:

drive means for driving a body to be controlled;
state observing means for observing a moving state of the body to be controlled and producing a state observation signal;
desired value producing means for producing a state desired value for the body to be controlled;
robust stabilizing compensation means for producing a control signal for said drive means from the state observation signal produced by said state observing means and the state desired value produced by said desired value producing means;
test signal generating means for generating and adding a test signal to a control system of said body to be controlled by said robust stabilizing compensation means;
test output signal detecting means for detecting the test signal;
arithmetic means for calculating a parameter of said robust stabilizing compensation means using the test signal;
and
parameter changing means for changing the parameter of said robust stabilizing compensation means, based on the calculation by said arithmetic means, wherein said robust stabilizing compensation means comprises a frequency shaping compensator and a robust compensator, wherein said arithmetic means calculates a model representing a dynamic behavior of a controlled object consisting of the body to be controlled, said driving means, and said state observing means, the controlled object comprising said frequency shaping compensator whereby the controlled object is a frequency-shaped controlled object;
wherein said arithmetic means calculates a normalized coprime factorization for the frequency-shaped, controlled object;
wherein said arithmetic means calculates an upper limit of an H.sub..infin. norm of variations of a numerator rational function and a denominator rational function in the normalized coprime factorization;
wherein said arithmetic means designates a variation value smaller than the upper limit of the H.sub..infin. norm of said variations, based on the upper limit of the H.sub..infin. norm of said variations;
and wherein said arithmetic means calculates a robust compensator based on the calculated normalized coprime factorization.

10 more elements

A control apparatus comprising:

drive means for driving a body to be controlled;
state observing means for observing a moving state of the body to be controlled and producing a state observation signal;
desired value producing means for producing a state desired value for the body to be controlled;
robust stabilizing compensation means for producing a control signal for said drive means from the state observation signal produced by said state observing means and the state desired value produced by said desired value producing means;
test signal generating means for generating and adding a test signal to a control system of said body to be controlled by said robust stabilizing compensation means;
test output signal detecting means for detecting the test signal;
arithmetic means for calculating a parameter of said robust stabilizing compensation means using the test signal;
and
parameter changing means for changing the parameter of said robust stabilizing compensation means, based on the calculation by said arithmetic means, wherein said arithmetic means has a model for a controlled object consisting of said body to be controlled, said drive means, and said state observing means;
wherein an integrator and a proportional gain are connected in parallel to an observation output terminal of a state-space model of said controlled object;
wherein a sum of an output from said integrator and an output from said proportional gain is set as a state observation output of an expanded, generalized plant in a standard H.sub..infin. problem;
wherein products of the output from said integrator, an internal state amount of the state-space model of said controlled object, and a control input of said state-space model by respectively proper constant weight matrices are set as control outputs of said expanded, generalized plant;
wherein a set of products of a first derivative of the internal state amount of the state-space model and an observation output from the state-space model of said controlled object by respectively proper weight functions is set as an exogenous input of said expanded, generalized plant;
wherein a robust stabilizing compensator is calculated so as to minimize a H.sub..infin. norm of from the exogenous input of said expanded, generalized plant to the control outputs of said expanded, generalized plant and to stabilize said expanded, generalized plant;
and wherein the parameter of said robust stabilizing compensation means for said controlled object is calculated by a robust compensator, said integrator, and the proportional gain.

12 more elements

A stage apparatus comprising:

a stage;
and
a control apparatus controlling said stage, comprising:
drive means for driving said stage;
state observing means for observing a moving state of said stage and producing a state observation signal;
desired value producing means for producing a state desired value for said stage;
robust stabilizing compensation means for producing a control signal for said drive means from the state observation signal produced by said state observing means and the state desired value produced by said desired value producing means;
test signal generating means for generating and adding a test signal to a control system of said stage by said robust stabilizing compensation means;
test output signal detecting means for detecting the test signal;
arithmetic means for calculating a parameter of said robust stabilizing compensation means using the test signal;
and
parameter changing means for changing the parameter of said robust stabilizing compensation means, based on the calculation by said arithmetic means, wherein said robust stabilizing compensation means comprises a frequency shaping compensator and a robust compensator, wherein said arithmetic means calculates a model representing a dynamic behavior of a controlled object consisting of said stage, said driving means, and said state observing means, the controlled object comprising said frequency shaping compensator whereby the controlled object is a frequency-shaped controlled object;
wherein said arithmetic means calculates a normalized coprime factorization for the frequency-shaped, controlled object;
wherein said arithmetic means calculates an upper limit of an H.sub..infin. norm of variations of a numerator rational function and a denominator rational function in the normalized coprime factorization;
wherein said arithmetic means designates a variation value smaller than the upper limit of the H.sub..infin. norm of said variations, based on the upper limit of the H.sub..infin. norm of said variations;
and wherein said arithmetic means calculates a robust compensator based on the calculated normalized coprime factorization.

13 more elements

A hard disk servo writer apparatus comprising:

a writing head;
and
a control apparatus controlling the writing head, comprising:
drive means for driving said writing head;
state observing means for observing a moving state of said writing head and producing a state observation signal;
desired value producing means for producing a state desired value for said writing head;
robust stabilizing compensation means for producing a control signal for said drive means from the state observation signal produced by said state observing means and the state desired value produced by said desired value producing means;
test signal generating means for generating and adding a test signal to a control system of said writing head by said robust stabilizing compensation means;
test output signal detecting means for detecting the test signal;
arithmetic means for calculating a parameter of said robust stabilizing compensation means using the test signal;
and
parameter changing means for changing the parameter of said robust stabilizing compensation means, based on the calculation by said arithmetic means, wherein said robust stabilizing compensation means comprises a frequency shaping compensator and a robust compensator, wherein said arithmetic means calculates a model representing a dynamic behavior of a controlled object consisting of said writing head, said driving means, and said state observing means, the controlled object comprising said frequency shaping compensator whereby the controlled object is a frequency-shaped controlled object;
wherein said arithmetic means calculates a normalized coprime factorization for the frequency-shaped, controlled object;
wherein said arithmetic means calculates an upper limit of an H.sub..infin. norm of variations of a numerator rational function and a denominator rational function in the normalized coprime factorization;
wherein said arithmetic means designates a variation value smaller than the upper limit of the H.sub..infin. norm of said variations, based on the upper limit of the H.sub..infin. norm of said variations;
and wherein said arithmetic means calculates a robust compensator based on the calculated normalized coprime factorization.

13 more elements

A stage apparatus comprising:

a stage;
and
a control apparatus controlling said stage, comprising:
drive means for driving said stage;
state observing means for observing a moving state of the body to be controlled and producing a state observation signal;
desired value producing means for producing a state desired value for said stage;
robust stabilizing compensation means for producing a control signal for said drive means from the state observation signal produced by said state observing means and the state desired value produced by said desired value producing means;
test signal generating means for generating and adding a test signal to a control system of said stage by said robust stabilizing compensation means;
test output signal detecting means for detecting the test signal;
arithmetic means for calculating a parameter of said robust stabilizing compensation means using the test signal;
and
parameter changing means for changing the parameter of said robust stabilizing compensation means, based on the calculation by said arithmetic means, wherein said arithmetic means has a model for a controlled object consisting of said Stage, said drive means, and said state observing means;
wherein an integrator and a proportional gain are connected in parallel to an observation output terminal of a state-space model of said controlled object;
wherein a sum of an output from said integrator and an output from said proportional gain is set as a state observation output of an expanded, generalized plant in a standard H.sub..infin. problem;
wherein products of the output from said integrator, an internal state amount of the state-space model of said controlled object, and a control input of said state-space model by respectively proper constant weight matrices are set as control outputs of said expanded, generalized plant;
wherein a set of products of a first derivative of the internal state amount of the state-space model and an observation output from the state-space model of said controlled object by respectively proper weight functions is set as an exogenous input of said expanded, generalized plant;
wherein a robust stabilizing compensator is calculated so as to minimize a H.sub..infin. norm of from the exogenous input of said expanded, generalized plant to the control outputs of said expanded, generalized plant and to stabilize said expanded, generalized plant;
and wherein the parameter of said robust stabilizing compensation means for said controlled object is calculated by a robust compensator, said integrator, and the proportional gain.

15 more elements

A hard disk servowriter apparatus, comprising:

a writing head;
and
a control apparatus controlling said writing head, comprising:
drive means for driving said writing head;
state observing means for observing a moving state of said writing head and producing a state observation signal;
desired value producing means for producing a state desired value for said writing head;
robust stabilizing compensation means for producing a control signal for said drive means from the state observation signal produced by said state observing means and the state desired value produced by said desired value producing means;
test signal generating means for generating and adding a test signal to a control system of said writing head by said robust stabilizing compensation means;
test output signal detecting means for detecting the test signal;
arithmetic means for calculating a parameter of said robust stabilizing compensation means using the test signal;
and
parameter changing means for changing the parameter of said robust stabilizing compensation means, based on the calculation by said arithmetic means, wherein said arithmetic means has a model for a controlled object consisting of said writing head, said drive means, and said state observing means;
wherein an integrator and a proportional gain are connected in parallel to an observation output terminal of a state-space model of said controlled object;
wherein a sum of an output from said integrator and an output from said proportional gain is set as a state observation output of an expanded, generalized plant in a standard H.sub..infin. problem;
wherein products of the output from said integrator, an internal state amount of the state-space model of said controlled object, and a control input of said state-space model by respectively proper constant weight matrices are set as control outputs of said expanded, generalized plant;
wherein a set of products of a first derivative of the internal state amount of the state-space model and an observation output from the state-space model of said controlled object by respectively proper weight functions is set as an exogenous input of said expanded, generalized plant;
wherein a robust stabilizing compensator is calculated so as to minimize a H.sub..infin. norm of from the exogenous input of said expanded, generalized plant to the control outputs of said expanded, generalized plant and to stabilize said expanded, generalized plant;
and wherein the parameter of said robust stabilizing compensation means for said controlled object is calculated by a robust compensator, said integrator, and the proportional gain.

15 more elements

Dependencies are inferred from the claim text.