Method and apparatus for diagnosis of sensors faults using adaptive fuzzy logic
First Claim
1. A method for detecting faults in a vehicle control system, said method comprising:
- identifying a plurality of potential faults;
identifying a plurality of measured values in the control system;
identifying a plurality of estimated values based on models in the control system;
identifying a plurality of residual error values as the difference between the estimated values and the measured values;
identifying a plurality of vehicle operation regions and/or vehicle operating conditions;
defining a plurality of membership functions for each residual error value where the membership functions are adapted based on a current vehicle operating region and/or vehicle operating conditions from the plurality of vehicle operation regions and/or vehicle operating conditions;
determining a degree of membership value for each residual error value based on the membership functions; and
determining whether a fault exists by analyzing the degree of membership values.
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Abstract
A method for monitoring the sensors in a vehicle control system. The method includes identifying a plurality of potential faults, identifying a plurality of measured values, and identifying a plurality of estimated values based on models in the control system. The method further includes identifying a plurality of residual error values as the difference between the estimated values and the measured values. The method also defines a plurality of fuzzy logic membership functions for each residual error value. The fuzzy logic membership functions are adaptive in that they change depending on the vehicle operating region, i.e., the non-linearity level of the vehicle, and the vehicle operating conditions, i.e., steady state verses transients. A degree of membership value is determined for each residual error value based on the membership functions. The degree of membership values are then analyzed in a fuzzy logic reasoning system to determine whether a potential fault exists.
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Citations
25 Claims
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1. A method for detecting faults in a vehicle control system, said method comprising:
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identifying a plurality of potential faults; identifying a plurality of measured values in the control system; identifying a plurality of estimated values based on models in the control system; identifying a plurality of residual error values as the difference between the estimated values and the measured values; identifying a plurality of vehicle operation regions and/or vehicle operating conditions; defining a plurality of membership functions for each residual error value where the membership functions are adapted based on a current vehicle operating region and/or vehicle operating conditions from the plurality of vehicle operation regions and/or vehicle operating conditions; determining a degree of membership value for each residual error value based on the membership functions; and determining whether a fault exists by analyzing the degree of membership values. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for detecting a fault in a vehicle control system, said method comprising:
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identifying a plurality of potential faults; identifying a plurality of measured values in the control system; identifying a plurality of estimated values based on models in the control system; identifying a plurality of residual error values as the difference between the estimated values and the measured values; identifying a plurality of vehicle operation regions and/or vehicle operating conditions; defining at least three membership functions for each residual error value where the membership functions are changed in response to changes of a current vehicle operating region and/or vehicle operating conditions from the plurality of vehicle operation regions and/or vehicle operating conditions; determining a degree of membership value for each residual error value including assigning one of the degree of membership values to each residual for each potential fault; and determining whether a fault exists by analyzing the degree of membership values, wherein determining whether a fault exists includes determining whether a particular set of degree of membership values exceeds a predetermined threshold in a certain pattern. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A system for detecting a fault in a vehicle control system, said system comprising:
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means for identifying a plurality of potential faults; means for identifying a plurality of measured values in the control system; means for identifying a plurality of estimated values based on models in the control system; means for identifying a plurality of residual error values as the difference between the estimated values and the measured values; means for identifying a plurality of vehicle operation regions and/or vehicle operating conditions; means for defining a plurality of degree of membership functions for each residual error value where the membership functions are adapted based on current vehicle operating region and/or vehicle operating conditions from the plurality of vehicle operating regions and/or vehicle operating conditions; means for determining a degree of membership value for each residual error value based on the membership functions; and means for determining whether a fault exists by analyzing the degree of membership values. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25)
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Specification