Device for evaluating the transverse acceleration of an automobile vehicle and corresponding method
First Claim
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1. A device for evaluating transverse acceleration of an automobile vehicle, comprising:
- means for measuring rotational speeds of two wheels of the vehicle;
a module that estimates the transverse acceleration of the vehicle from the measured speeds; and
a validation module that calculates, as a function of operating parameters of the vehicle, a Boolean skidding variable which is negative if slipping of one of the two wheels is not detected, and which is positive if slipping of at least one of the two wheels is detected,in which the validation module comprises a first Boolean module that delivers a first Boolean wheel over-acceleration variable, which first Boolean module comprises first means for calculating the accelerations of the two wheels, second means for calculating a plausible acceleration threshold for the wheels as a function of the transmission ratio engaged, first means for comparison of the accelerations of each of the two wheels with respect to the plausible acceleration threshold, second means for comparison of the difference in speed between the two wheels with respect to a difference threshold, and means for storing the Boolean wheel over-acceleration variable,wherein the first Boolean module assigns a positive value to the wheel over-acceleration variable if the first means for comparison determines that the acceleration of either of the two wheels is greater than the plausible acceleration threshold, andin which, when the acceleration of either of the two wheels is not greater than the plausible acceleration threshold, the first Boolean module assigns a negative value to the wheel over-acceleration variable if the second means for comparison determines that the difference between speeds of the two wheels is less than the difference threshold, and the first Boolean module assigns a value that the wheel over-acceleration variable had at a preceding calculation time, extracted from the means for storing, to the wheel over-acceleration variable if the second means for comparison determines that the difference between speeds of the two wheels is less than the difference threshold.
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Abstract
A device for evaluating the transverse acceleration of a motor vehicle measures the rotational speeds of two wheels of the vehicle, estimates the transverse acceleration of the vehicle from these speeds, and calculates, as a function of vehicle operating parameters, particularly of the rotational speeds of the wheels and of the transmission ratio engaged, a Boolean slip variable which is negative if the transverse estimated acceleration is relevant for detecting a bend, and which is positive if the reverse is true.
25 Citations
11 Claims
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1. A device for evaluating transverse acceleration of an automobile vehicle, comprising:
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means for measuring rotational speeds of two wheels of the vehicle; a module that estimates the transverse acceleration of the vehicle from the measured speeds; and a validation module that calculates, as a function of operating parameters of the vehicle, a Boolean skidding variable which is negative if slipping of one of the two wheels is not detected, and which is positive if slipping of at least one of the two wheels is detected, in which the validation module comprises a first Boolean module that delivers a first Boolean wheel over-acceleration variable, which first Boolean module comprises first means for calculating the accelerations of the two wheels, second means for calculating a plausible acceleration threshold for the wheels as a function of the transmission ratio engaged, first means for comparison of the accelerations of each of the two wheels with respect to the plausible acceleration threshold, second means for comparison of the difference in speed between the two wheels with respect to a difference threshold, and means for storing the Boolean wheel over-acceleration variable, wherein the first Boolean module assigns a positive value to the wheel over-acceleration variable if the first means for comparison determines that the acceleration of either of the two wheels is greater than the plausible acceleration threshold, and in which, when the acceleration of either of the two wheels is not greater than the plausible acceleration threshold, the first Boolean module assigns a negative value to the wheel over-acceleration variable if the second means for comparison determines that the difference between speeds of the two wheels is less than the difference threshold, and the first Boolean module assigns a value that the wheel over-acceleration variable had at a preceding calculation time, extracted from the means for storing, to the wheel over-acceleration variable if the second means for comparison determines that the difference between speeds of the two wheels is less than the difference threshold. - View Dependent Claims (2, 3, 4, 5, 6, 10)
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7. A method for evaluating the transverse acceleration of an automobile vehicle, comprising:
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measuring, via sensors of the vehicle, rotational speeds of two drive wheels of the vehicle; estimating transverse acceleration of the vehicle from the measured wheel speeds; and calculating, via a processor of the vehicle, a Boolean skidding variable as a function of operating parameters of the vehicle, which variable is negative if slipping of the two wheels is not detected, and which is positive if slipping of at least one of the two wheels is detected, wherein the calculating of the Boolean skidding variable further includes determining a first Boolean wheel over-acceleration variable, and in which the first Boolean wheel over-acceleration variable is determined by determining, using a stored data map, a plausible wheel acceleration threshold as a function of the transmission ratio engaged;
if the derivative with respect to time of one of the measured wheel rotational speeds is greater than the plausible wheel acceleration threshold, the wheel over-acceleration variable is positive;
if the two derivatives with respect to time of the measured wheel rotational speeds are less than this plausible wheel acceleration threshold and if, simultaneously, the difference in rotational speeds of the two wheels is less than a difference threshold, the wheel over-acceleration variable is negative; and
in other cases, the wheel over-acceleration variable maintains a previous value. - View Dependent Claims (8, 9, 11)
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Specification