System for controlling the stability of a vehicle using an algorithm comparing average slopes of variation of a parameter
First Claim
1. A vehicle stability control system in which a characteristic parameter Q of a functioning of a tire of the vehicle intended to roll on the ground varies as a function of a parameter P according to a certain law, an optimum value of the parameter P being imposed by a controller directly or indirectly, so as to act on at least one of elements chosen from a group comprising a rotation torque applied to the tire, a steering angle of the tire, a camber angle of the tire, and a vertical force applied to the tire, in which the controller comprises means for:
- determining coefficients A[avg/p], by direct calculation or by a regression, from a sufficient number of pairs (Pi, Qi), so as to model a first variation curve Qi=f(Pi, A[avg/p]) including the origin, and the pair or pairs (Qi, Pi), in which Qi is different from zero, determining an indicator of the average slope α
1 of the first variation curve, determining coefficients B[avg/p], by direct calculation or by a regression, from a sufficient number of pairs (Qi, Pi), so as to model a second variation curve Qi=f(Pi, B[avg/p]) including the pair or pairs (Qi, Pi), in which Qi is different from zero, determining an indicator of the average slope α
2 of the second variation curve, as long as the difference between α
1 and α
2 is less than a predetermined slope threshold, repeating the previous operations for each new acquisition of a pair of values (Pi, Qi), if the difference between α
1 and α
2 exceeds the predetermined slope threshold, determining a target slip PCavg using at least the last pair of values (Pi, Qi).
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Accused Products
Abstract
System for controlling the stability of a vehicle, the system comprising means for imparting a longitudinal force on the tire and means for calculating the slip parameter GOpt at each activation of the means for imparting a longitudinal force on the tire in the following manner: determining coefficients A[avg/p] by direct calculation or by an appropriate regression, from a sufficient number of pairs (μi, Gi), so as to model a first curve of variation μi=f(Gi, A[avg/p]) including the origin, and the pair or pairs (μi, Gi), in which μi is different from zero, determining an indicator of the average slope α1 of the first variation curve, determining coefficients B[avg/p] by direct calculation or by an appropriate regression, from a sufficient number of pairs (μi, Gi), so as to model a second variation curve, free not to pass through the origin, μi=f(Gi, B[avg/p]) including the pair or pairs (μi, Gi), in which μi is different from zero, determining an indicator of the average slope α2 of the second variation curve, as long as the difference between α1 and α2 is below a predetermined slope threshold, repeating the previous operations for each new acquisition of the pair of values (Gi, μi), as soon as the difference between α1 and α2 exceeds the predetermined slope threshold and determining a target slip GCavg using at least the last pair of values (Gi, μi).
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Citations
32 Claims
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1. A vehicle stability control system in which a characteristic parameter Q of a functioning of a tire of the vehicle intended to roll on the ground varies as a function of a parameter P according to a certain law, an optimum value of the parameter P being imposed by a controller directly or indirectly, so as to act on at least one of elements chosen from a group comprising a rotation torque applied to the tire, a steering angle of the tire, a camber angle of the tire, and a vertical force applied to the tire, in which the controller comprises means for:
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determining coefficients A[avg/p], by direct calculation or by a regression, from a sufficient number of pairs (Pi, Qi), so as to model a first variation curve Qi=f(Pi, A[avg/p]) including the origin, and the pair or pairs (Qi, Pi), in which Qi is different from zero, determining an indicator of the average slope α
1 of the first variation curve,determining coefficients B[avg/p], by direct calculation or by a regression, from a sufficient number of pairs (Qi, Pi), so as to model a second variation curve Qi=f(Pi, B[avg/p]) including the pair or pairs (Qi, Pi), in which Qi is different from zero, determining an indicator of the average slope α
2 of the second variation curve,as long as the difference between α
1 and α
2 is less than a predetermined slope threshold, repeating the previous operations for each new acquisition of a pair of values (Pi, Qi),if the difference between α
1 and α
2 exceeds the predetermined slope threshold, determining a target slip PCavg using at least the last pair of values (Pi, Qi). - View Dependent Claims (16)
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2. A vehicle stability control system, in which a parameter G is a slip of a tire and a characteristic parameter μ
- is a coefficient of friction of the tire, the system comprising means for imparting a longitudinal force to the tire, means of modulating the longitudinal force, and means for calculating an optimal slip parameter GOpt at each activation of the means for imparting a longitudinal force to the tire in the following manner;
determining coefficients A[avg/p] by direct calculation or by a regression, from a sufficient number of pairs (μ
i, Gi), so as to model a first variation curve μ
i=f(Gi, A[avg/p]) including the origin, and the pair or pairs (μ
i, Gi), in which μ
i is different from zero,determining an indicator of an average slope α
1 of the first variation curve,determining coefficients B[avg/p] by direct calculation or by a regression, from a sufficient number of pairs (μ
i, Gi), so as to model a second variation curve μ
i=f(Gi, B[avg/p]) including the pair or pairs (μ
i, Gi), in which μ
i is different from zero,determining an indicator of an average slope α
2 of the second variation curve,as long as a difference between α
1 and α
2 is less than a predetermined slope threshold, repeating the previous operations for each new acquisition of a pair of values (Gi, μ
i),if the difference between α
1 and α
2 exceeds the predetermined slope threshold, determining a target slip GCavg using at least the last pair of values (Gi, μ
i). - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- is a coefficient of friction of the tire, the system comprising means for imparting a longitudinal force to the tire, means of modulating the longitudinal force, and means for calculating an optimal slip parameter GOpt at each activation of the means for imparting a longitudinal force to the tire in the following manner;
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17. A tire testing system in which a characteristic parameter Q of a functioning of a tire under test varies as a function of a parameter P according to a certain law, an optimum value of the parameter P being imposed by a controller directly or indirectly, so as to act on at least one of elements chosen from a group comprising a rotation torque applied to the tire, a steering angle of the tire, a camber angle of the tire, and a vertical force applied to the tire, in which the controller comprises means for:
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determining coefficients A[avg/p] by direct calculation or by a regression, from a sufficient number of pairs (Pi, Qi), so as to model a first variation curve Qi=f(Pi, A[avg/p]) including the origin, and the pair or pairs (Qi, Pi), in which μ
i is different from zero,determining an indicator of an average slope α
1 of the first variation curve,determining coefficients B[avg/p] by direct calculation or by a regression, from a sufficient number of pairs (Qi, Pi), so as to model a second variation curve Qi=f(Pi, B[avg/p]) including the pair or pairs (Qi, Pi), in which Qi is different from zero, determining an indicator of an average slope α
2 of the second variation curve,as long as a difference between α
1 and α
2 is less than a predetermined slope threshold, repeating the previous operations for each new acquisition of a pair of values (Pi, Qi),if the difference between α
1 and α
2 exceeds the predetermined slope threshold, determining a target slip PCavg using at least the last pair of values (Pi, Qi). - View Dependent Claims (32)
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18. A tire testing system, in which a parameter G is a slip of the tire and a characteristic parameter μ
- is a coefficient of friction of the tire, the system comprising means for imparting a longitudinal force to the tire, means for modulating the longitudinal force and means for calculating a slip parameter GOpt at each activation of the means for imparting a longitudinal force to the tire in the following manner;
determining coefficients A[avg/p] by direct calculation or by a regression, from a sufficient number of pairs (μ
i, Gi), so as to model a first variation curve μ
i=f(Gi, A[avg/p]) including the origin, and the pair or pairs (μ
i, Gi), in which μ
i is different from zero,determining an indicator of an average slope α
1 of the first variation curve,determining coefficients B[avg/p] by direct calculation or by a regression, from a sufficient number of pairs (μ
i, Gi), so as to model a second variation curve μ
i=f(Gi, B[avg/p]) including the pair or pairs (μ
i, Gi), in which μ
i is different from zero,determining an indicator of an average slope α
2 of the second variation curve,as long as a difference between α
1 and α
2 is less than a predetermined slope threshold, repeating the previous operations for each new acquisition of a pair of values (Gi, μ
i),if the difference between α
1 and α
2 exceeds the predetermined slope threshold, determining a target slip GCavg using at least the last pair of values (Gi, μ
i). - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
- is a coefficient of friction of the tire, the system comprising means for imparting a longitudinal force to the tire, means for modulating the longitudinal force and means for calculating a slip parameter GOpt at each activation of the means for imparting a longitudinal force to the tire in the following manner;
Specification