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Apparatus for controlling lock-up clutch in vehicle automatic transmission according to fuzzy set theory

  • US 5,095,435 A
  • Filed: 08/17/1990
  • Issued: 03/10/1992
  • Est. Priority Date: 08/25/1989
  • Status: Expired due to Term
First Claim
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1. An apparatus for controlling a lock-up clutch of an automatic transmission for a motor vehicle wherein an engine is connected to a speed changing mechanism through a fluid coupling when said lock-up clutch is placed in a released position, and is directly connected to said speed changing mechanism when said lock-up clutch is placed in an engaged position, said released and engaged positions of the lock-up clutch being selected according to a predetermined clutch control pattern, said apparatus comprising:

  • determining means for determining degrees of satisfaction of each of at least one basic fuzzy set theory rule which corresponds to said released and engaged positions of said lock-up clutch, respectively, based on said predetermined clutch control pattern;

    detecting means for detecting a running condition of the vehicle;

    first calculating means for calculating degrees of satisfaction of fuzzy set control rules, which correspond to said released and engaged positions, respectively, depending upon the running condition of the vehicle detected by said detecting means;

    second calculating means for calculating overall degrees of adequacy for selecting said released and engaged positions, respectively, based on the degrees of satisfaction of said at least one basic fuzzy set theory rule determined by said determining means and the degrees of satisfaction of said fuzzy set control rules calculated by said first calculating means; and

    selecting means for selecting one of said released and engaged positions of the lock-up clutch, based on said overall degrees of adequacy calculated by said second calculating means, so that the lock-up clutch is placed in the selected one of the released and engaged positions.

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