System for controlling the stability of a vehicle using several predictive algorithms and a selection process
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 estimations or measurements (Pi, Qi) for “
i”
successive levels of values;
using “
n”
calculation algorithms, each determining a target value for the parameter P, to obtain a target value PCn for each algorithm,selecting as the optimum value of the parameter P one of the target values PCn based at least in part on a comparison of each of the “
n”
target values PCn to at least one other one of the “
n”
target values PCn.
1 Assignment
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Accused Products
Abstract
System for controlling the stability of a vehicle, the system comprising means for imparting a longitudinal force to the tire and means for calculating a slip GOpt by determining the values of the coefficient of friction μi, for each slip Gi corresponding to successive levels “i”, using in parallel “n” calculation algorithms each determining a target value of the slip making it possible thus to obtain as many target values GCn as there are algorithms used, the system selecting the best of the target values GCn as the optimum slip value GOpt by subjecting the “n” target values GCn to comparisons aimed at eliminating the least likely target values, the comparisons being made on the basis of a function f(λ) of a descriptor of the physical functioning of the rotation of the tire on the ground making it possible to calculate characteristic values. For example, one interesting characteristic value is the variation in G with respect to time.
31 Citations
39 Claims
-
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 estimations or measurements (Pi, Qi) for “
i”
successive levels of values;using “
n”
calculation algorithms, each determining a target value for the parameter P, to obtain a target value PCn for each algorithm,selecting as the optimum value of the parameter P one of the target values PCn based at least in part on a comparison of each of the “
n”
target values PCn to at least one other one of the “
n”
target values PCn.
-
-
2. A vehicle stability control 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 an optimal slip parameter GOpt at each activation of the means for imparting a longitudinal force to the tire, in the following manner;
determining the values of the coefficient of friction μ
i, for each slip Gi corresponding to “
i”
successive levels of the longitudinal force,using “
n”
calculation algorithms, each determining a target value for the slip G, to obtain a target value GCn for each algorithm,selecting as the optimum slip value GOpt one of the target values GCn by subjecting the “
n”
target values GCn to comparisons aimed at eliminating the least likely target values. - View Dependent Claims (3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
- 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 an optimal slip parameter GOpt at each activation of the means for imparting a longitudinal force to the tire, in the following manner;
-
35. A vehicle stability control system wherein a first of the calculation algorithms determines an “
- Invariant”
based on analysis of the coefficient of friction as a function of the slip, resulting in a target slip GCinvt, a second of the calculation algorithms is an “
average”
algorithm that detects changes in curvature of a curve μ
(G), resulting in a target slip GCavg, and a third of the calculation algorithms is particularly designed for calculating a target slip on wet ground, resulting in a target slip GCwet, and the selection of the optimum slip is made in the following manner;preselecting a value GCl in the following manner; if a variation in G with respect to time lies within a predetermined range, then the value GCl is equal to GCavg, if the variation in G with respect to time does not lie within the predetermined range and if a difference GE2 in absolute value between GCinvt and GCavg lies within a predetermined optimized range, then the value GCl is equal to GCinvt, if the variation in G with respect to time does not lie within the predetermined range and if the difference GE2 in absolute value between GCinvt and GCl does not lie within the predetermined optimized range, then the value GCl is equal to GCavg, calculating a relative difference in absolute value GE between GCl and GCwet, selecting the value of GOpt in the following manner; as long as the variation in G with respect to time lies within a predetermined zone, adopting, as the value GOpt, the value of GCl, when the variation in G with respect to time does not lie within the predetermined zone, a critical range is determined whose amplitude depends on the variation in G with respect to time, and; if GE lies within the predetermined critical range, adopting, as the value GOpt, the value of GCl, if GE does not lie within the predetermined critical range, adopting, as the value GOpt, the value of GCwet. - View Dependent Claims (36, 37, 38)
- Invariant”
-
39. A vehicle stability control system, in which a parameter P is the drift angle δ
- of the tire and a characteristic parameter Q is the drift thrust Fy of the tire, the system comprising means for controlling a parameter “
ξ
”
according to instructions entered by a driver of the vehicle on a control means and according to instructions delivered by a path controller, means of modulating the parameter “
ξ
” and
means for calculating the drift angle parameter δ
Opt at each activation of the means for entering the parameter “
ξ
”
in the following manner;each time the system for controlling a variation in ξ
is activated, for at least two different levels “
i”
of the drift angle, reading a plurality of values of FYi, and the associated drift angle δ
i obtained by estimation or direct measurement,using “
n”
calculation algorithms, each determining a target value of the drift angle δ
, to obtain a target value δ
Cn for each algorithms,selecting, as the optimum value of the drift angle, one of the target values δ
Cn by subjecting the “
n”
target values δ
Cn to comparisons aimed at eliminating the least likely target values.
- of the tire and a characteristic parameter Q is the drift thrust Fy of the tire, the system comprising means for controlling a parameter “
Specification