Fuzzy microcontroller for complex nonlinear signal recognition
First Claim
1. An apparatus for detecting a vehicle crash in response to an acceleration sensor signal, comprising:
- first means for outputting an average value signal corresponding to an average value of said acceleration sensor signal, said first means adjusting said average value signal on the basis of a first relationship between said acceleration sensor signal and a first group of membership functions, said first group of membership functions each having a center corresponding to said average value signal;
second means for determining a change in said acceleration sensor signal on the basis of a second relationship between said acceleration sensor signal and a second group of membership functions;
third means for determining a deviation in said acceleration sensor signal from said average value signal on the basis of a third relationship between said acceleration sensor signal and a third group of membership functions each having a center corresponding to said average value signal;
fourth means for outputting an accumulated energy signal generated on the basis of a winning rule from a set of rules, each of said rules having rule terms corresponding to at least one of said membership functions of said first, second and third membership functions, said fourth means comprising means for determining said winning rule on the basis of said second and third relationships; and
fifth means for outputting a crash detection signal on the basis of a comparison between said accumulated energy signal and said average value signal.
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Accused Products
Abstract
An arrangement (apparatus and method) using fuzzy logic for performing signal processing functions to determine the occurrence of an event, such as a vehicle crash. An acceleration sensor signal is fuzzified by comparison with dynamic membership functions having adjustable centers from feedback inputs. Each crisp input is fuzzified by determining the distance of the crisp input from the center of the membership function and linearly complementing the result with respect to the width of the membership function, thereby eliminating the necessity for determining the shape of the membership function. The dynamic membership functions are used to generate an average level signal, and an accummulated energy signal. A crash detection signal is generated after a comparison between the dynamically-adjusted average level and accummulated energy signals. The uses of the dynamic membership functions provide reliable detection and a low-cost implementation.
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Citations
22 Claims
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1. An apparatus for detecting a vehicle crash in response to an acceleration sensor signal, comprising:
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first means for outputting an average value signal corresponding to an average value of said acceleration sensor signal, said first means adjusting said average value signal on the basis of a first relationship between said acceleration sensor signal and a first group of membership functions, said first group of membership functions each having a center corresponding to said average value signal; second means for determining a change in said acceleration sensor signal on the basis of a second relationship between said acceleration sensor signal and a second group of membership functions; third means for determining a deviation in said acceleration sensor signal from said average value signal on the basis of a third relationship between said acceleration sensor signal and a third group of membership functions each having a center corresponding to said average value signal; fourth means for outputting an accumulated energy signal generated on the basis of a winning rule from a set of rules, each of said rules having rule terms corresponding to at least one of said membership functions of said first, second and third membership functions, said fourth means comprising means for determining said winning rule on the basis of said second and third relationships; and fifth means for outputting a crash detection signal on the basis of a comparison between said accumulated energy signal and said average value signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A fuzzy signal processor for measuring accumulated energy from an acceleration sensor signal, comprising:
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a fuzzy low-pass filter for outputting a filtered acceleration sensor signal, said fuzzy low-pass filter comprising a first group of membership functions having said filtered acceleration sensor signal as an assigned center; a fuzzy calculator for determining a change in said acceleration sensor signal with respect to time, said change being calculated on the basis of a second group of membership functions having a time-delayed value of said acceleration sensor signal as an assigned center; a fuzzy comparator for calculating a deviation in said acceleration sensor signal from said filtered acceleration sensor signal on the basis of a third group of membership functions having said filtered acceleration sensor signal as a center; means for calculating the accumulated energy in said acceleration sensor signal on the basis of said filtered acceleration sensor signal, said change in said acceleration sensor signal, and said deviation in said acceleration sensor signal over time. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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19. A method for detecting accumulated energy in response to an acceleration sensor signal, comprising the steps of:
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adjusting an average value signal corresponding to an average value of said acceleration sensor signal on the basis of a comparison between said acceleration sensor signal and a first group of membership functions each having a center corresponding to said average value signal; determining changes in said acceleration sensor signal based on a second group of membership functions having a time-delayed value of said acceleration sensor signal as an assigned center; determining deviations in said acceleration sensor signal from said average value signal on the basis of a third group of membership functions each having a center corresponding to said average value signal; determining a winning rule from a set of rules stored in a rule memory, each of said rules having rule terms corresponding to said second and third groups of membership functions, said winning rule being determined on the basis of a relational comparison between said set of rules and said changes and said deviations in said acceleration sensor signal; dynamically adjusting an accumulated energy signal on the basis of said winning rule within a predetermined interval. - View Dependent Claims (20, 21, 22)
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Specification