Data processing: generic control systems or specific application – Generic control system – apparatus or process – Optimization or adaptive control
Reexamination Certificate
1998-06-12
2001-07-03
Etienne, Ario (Department: 2155)
Data processing: generic control systems or specific application
Generic control system, apparatus or process
Optimization or adaptive control
C700S280000, C700S279000, C700S188000, C702S056000, C381S071400
Reexamination Certificate
active
06256545
ABSTRACT:
The contents of the Applications No. Heisei 9-156604, with a filing date of Jun. 13, 1997 in Japan are herein incorporated by reference.
BACKGROUND OF THE INVENTION
a) Field of the Invention
The present invention relates generally to actively vibration reducing control apparatus and method applicable to a vehicular engine mount on which a vehicular engine as a vibration source is mounted.
The present invention particularly relates to adaptive control apparatus and method for actively reducing the vibration transmitted from the vehicular engine in which a control vibration developed from a control vibration source is interfered against a vibration transmitted from the engine to a vehicle body to reduce the transmission of the vibration and a load of an identification operation for a transfer function between the control vibration source and a residual vibration detector included in a control algorithm to drive the control vibration source is reduced and an improvement in an accuracy of the identification on the transfer function is achieved.
b) Description of the Related Art
In a case of various previously proposed active vibration reducing control apparatuses, transfer functions, each transfer function being established between a control vibration source and a residual vibration detector, are mutually different from each other according to characteristic deviations for respective apparatuses to which the previously proposed active vibration reducing control apparatus are applied and for respective installations on which the previously proposed actively vibration reducing apparatuses are installed.
In addition, there is a possibility that each of the transfer functions is varied from its originally established state due to its characteristic variation along with a use of the apparatus to which each of the previously proposed active vibration reducing apparatus is applied.
Hence, in order to execute a highly accurate vibration reducing control, it is desirable to identify the transfer function after each one of the previously proposed actively vibration reducing control apparatuses is incorporated into the apparatus to which each one thereof is applied or it is desirable to identify the transfer function whenever a regular check for the apparatus to which each one thereof is applied.
A Japanese Patent Application First Publication No Heisei 6-332471 published on Dec. 2, 1994 exemplifies a technique for identifying the transfer function described above.
In the above-identified Japanese Patent Application First Publication, an identification sound or an identification vibration is caused to be developed according to an impulse signal from a control source or a control vibration source and its response is measured by means of a residual noise detector or a residual vibration detector.
Consequently, the identification of the transfer function required in the control algorithm of an active noise controller or an active vibration controller can be achieved.
A time at which the identification sound or the identification vibration is developed according to the impulse signal is limited to a time immediately before the time transferred from a state in which a noise or the vibration from a noise source or a vibration source is not developed to a state in which the noise or the vibration is developed. Hence, the identification of the transfer function can be made without introduction of a remarkable increase in a calculation load on the controller and without an unpleasant feeling given to a human kind.
Furthermore, a Japanese Patent Application First Publication No. Heisei 3-259722 published on Nov. 19, 1991 exemplifies another technique of the identification of the transfer function.
In the latter Japanese Patent Application First Publication, a noise reducing apparatus in which a noise developed by a compressor installed in a refrigerator and radiated externally through a mechanical room duct is cancelled before the noise is to be radiated externally through the duct, a loud speaker and a microphone are installed to perform a noise reduction control within the duct, the control noise is developed from the loud speaker according to the drive state of the compressor to reduce the noise, and the identification sound is developed from the loud speaker according to a white noise whenever the compressor is halted in order to prevent a noise control characteristic from being deteriorated, and the transfer function between the loud speaker and the microphone is measured to identify a transfer function filter.
SUMMARY OF THE INVENTION
Since the identification of the transfer function required in the control is possible for each apparatus to which any one of previously proposed active vibration or noise reducing control apparatuses is applied, a highly accurate vibration reducing control can be expected.
On the other hand, although it is necessary to develop the identification sound according to the impulse signal or the white noise signal in order to identify the transfer function, the impulse signal or the white noise signal is a signal having frequency components of all frequency bands.
Hence, even though the identification sound is developed, an output is dispersed over a wide frequency band.
Then, if the whole output of the identification sound is sufficiently high, the output for each frequency component is slight so that the identification of the transfer function becomes insufficient.
Hence, it is required to develop the identification sound at a high output in order to sufficiently obtain the output for each frequency component.
To meet such a requirement as described above, since it is easy to apply the development of the identification sound at the high output to the actively noise reducing control apparatus in which the loud speaker is a control noise source if the loud speaker which can provide a large output power is secured in a space of a sufficient margin, the above requirement can be achieved with a relatively easiness.
However, in the case where the above requirement is applied to the actively vibration reducing control apparatus in which the vibration transmitted, e.g., from a vehicular engine to a vehicular body is reduced by a development of an active supporting force interposed between the vehicular engine and the vehicle body through an active engine mount, there is a limit in the active supporting force which can be developed by the active engine mount.
Hence, even though a large amplitude impulse signal or a large amplitude white noise is supplied to the active engine mount as the control vibration source, a level of the identification sound (or vibration) actually developed is not so high and it takes a long time to identify the transfer function.
In addition, when the actual vibration reducing control apparatus for the engine as the vibration source, the vibration developed from the vibration source is not a vibration such as the white noise which covers all frequency bands but generally a vibration concentrated into a particular frequency.
Hence, the identification sound (or vibration) using the white noise signal often cannot carry out the identification of the transfer function suitable for an actual use condition.
Furthermore, suppose a situation under which an actual identification of the transfer function is carried out.
In the case of the actively vibration reducing control apparatus, it is necessary to identify the transfer function using a controller mounted in the vehicle to carry out the identification of the transfer function for each vehicle in which the actively vibration reducing apparatus is mounted in an assembly line of a factory.
In addition, a time required to complete the identification is needed to be finished in a short period of time so as not to give a large influence on an assembly speed in the factory.
In other words, the identification in the transfer function for each vehicle is needed to be carried out by the controller mounted in each vehicle and having a relatively low capability and to be completed within a limited time period as is di
Kimura Takeshi
Satoh Shigeki
Backer Firmin
Etienne Ario
Foley & Lardner
Nissan Motor Co,. Ltd.
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