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US6144181A
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Method and apparatus for reducing resonance in a dual inertia system
Assignee: Allen Bradley Co LLC
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Filing: 1998-09-21
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Granted: 2000-11-07
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Expires: 2018-09-21
Abstract
Abstract A method and apparatus for minimizing resonant oscillations in a dual inertia system characterized by minimally stable poles and both a resonant frequency and an anti-resonant frequency, the apparatus including a notch filter which is tuned so that notch filter zeros essentially cancel the minimally stable poles and so that at least one notch pole is located at the intersection of a real axis and an system anti-resonant zero radius on a root-loci plot, thereby rendering an exceptionally stable system, the method for tuning the notch filter as described.
Inventors
- 👤 Thomas J. Rehm
- 👤 Peter B. Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:02
CPC Classifications
G; G05; G05B; G05B5/00; G05B5/01
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
144 words
A method for use in a configuration including a controller and a dual energy system, the system including a drive component and a load component, the controller controlling the drive component and the drive component driving the load component, the system characterized generally by a second order transfer function including two system resonant poles and two system zeros and having a resonant frequency ω r and an anti-resonant frequency ω ar , the method for minimizing resonance, the method comprising the steps of: providing a notch filter characterized by a Laplace domain transfer function: ##EQU15## where A is a tuning variable, R is a damping term and ω n is a natural frequency; and tuning the transfer function such that natural frequency ω n is equal to resonant frequency ω r and a damping term R=(ω ar /ω r )+(ω r /ω ar ).
Claim 2
Independent Claim
144 words
A method for use in a configuration including a controller and a dual energy system, the system including a drive component and a load component, the controller controlling the drive component and the drive component driving the load component, the system characterized generally by a second order transfer function including two system resonant poles and two system zeros and having a resonant frequency ω r and an anti-resonant frequency ω ar , the method for minimizing resonance, the method comprising the steps of: providing a notch filter characterized by a Laplace domain transfer function: ##EQU15## where A is a tuning variable, R is a damping term and ω n is a natural frequency; and tuning the transfer function such that natural frequency ω n is equal to resonant frequency ω r and a damping term R=(ω ar /ω r )+(ω r /ω ar ).
Claim 3
Dependent Claim
29 words
The method of claim 1 further including the steps of, prior to providing, determining both the system resonant frequency ω r and the system anti-resonant frequency ω ar .
Claim 4
Dependent Claim
53 words
The method of claim 2 wherein the step of determining the system resonant frequency includes the steps of determining a motor velocity error signal indicating the difference between a commanded motor velocity and an actual motor velocity and performing a Fast Fourier Transfer on the error signal to determine the system resonant frequency.
Claim 5
Dependent Claim
91 words
The method of claim 3 wherein the motor and load components are linked together via a shaft and the shaft is characterized by a spring constant k, the motor is characterized by a motor inertia J m and the load is characterized by a load inertia J l , each of the load and motor inertias J l and J m are known and the step of determining the anti-resonant frequency ω ar includes solving the equation: ##EQU16## to determine the value of constant k and then solving the equation: ##EQU17##
Claim 6
Independent Claim
227 words
A method for use in a configuration including a controller, a dual energy system and a notch filter, the system including a drive component and a load component, the controller controlling the drive component and the drive component driving the load component, the system characterized generally by a second order transfer function including two system resonant poles and two system zeros and having a resonant frequency T r and an anti-resonant frequency T ar , the notch filter characterized by a second order transfer function also having two poles and two zeros, the method for minimizing resonance and comprising the steps of: selecting notch filter transfer function zeros to cancel the system resonant poles wherein the notch filter transfer function in the Laplace domain is ##EQU18## where A is a tuning variable, R is a damping term and ω n is a natural frequency; and selecting notch filter poles so that both notch filter poles are on the real axis of a root-loci s-plane and one of the poles is on the real axis at a radius which is equal to the magnitude of the system zeros, the step of selecting notch filter poles including the step of tuning the notch filter such that natural frequency ω n is equal to resonant frequency ω r and damping term R=(T ar /T r )+(T r /T ar ).
Claim 7
Independent Claim
227 words
A method for use in a configuration including a controller, a dual energy system and a notch filter, the system including a drive component and a load component, the controller controlling the drive component and the drive component driving the load component, the system characterized generally by a second order transfer function including two system resonant poles and two system zeros and having a resonant frequency T r and an anti-resonant frequency T ar , the notch filter characterized by a second order transfer function also having two poles and two zeros, the method for minimizing resonance and comprising the steps of: selecting notch filter transfer function zeros to cancel the system resonant poles wherein the notch filter transfer function in the Laplace domain is ##EQU18## where A is a tuning variable, R is a damping term and ω n is a natural frequency; and selecting notch filter poles so that both notch filter poles are on the real axis of a root-loci s-plane and one of the poles is on the real axis at a radius which is equal to the magnitude of the system zeros, the step of selecting notch filter poles including the step of tuning the notch filter such that natural frequency ω n is equal to resonant frequency ω r and damping term R=(T ar /T r )+(T r /T ar ).
Claim 8
Dependent Claim
33 words
The method of claim 5 further including the steps of, prior to selecting the notch filter zeros, determining both the system resonant frequency ω r and the system anti-resonant frequency ω ar .
Claim 9
Dependent Claim
55 words
The method of claim 6 wherein the drive component is a motor and the method further includes the steps of determining a motor velocity error signal indicating the difference between a commanded motor velocity and an actual motor velocity and performs a Fast Fourier Transfer on the error signal to determine the system resonant frequency.
Claim 10
Dependent Claim
91 words
The method of claim 7 wherein the motor and load components are linked together via a shaft and the shaft is characterized by a spring constant k, the motor is characterized by a motor inertia J m and the load is characterized by a load inertia J l , each of the load and motor inertias J l and J m are known and the step of determining the anti-resonant frequency ω ar includes solving the equation: ##EQU19## to determine the value of constant k and then solving the equation: ##EQU20##
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-11-07 | 2004-05-08 | 2004-11-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-11-07 | 2008-05-08 | 2008-11-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-11-07 | 2012-05-08 | 2012-11-07 | $7700.00 | Window Closed / Lapsed |