SYSTEM FOR GENERATING AN ESTIMATION OF THE GROUND SPEED OF A VEHICLE FROM MEASURES OF THE ROTATION SPEED OF AT LEAST ONE WHEEL
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Accused Products
Abstract
A system for producing an estimation of the overall speed of a vehicle relative to the ground is described which comprises the generation of a measurement of the instantaneous road grip coefficient (μr) of at least one wheel (1) of a vehicle with electric traction wherein a rotary electric machine (2) is coupled to said wheel to drive it individually in traction and in braking. This system comprises an indicator of the torque applied at each instant to that wheel based on the measurement of the current (Ic) in the electric machine, an indicator of the instantaneous dynamic load on said wheel and a stage for calculating the instantaneous road grip coefficient of said wheel (1) relative to the ground based on the torque indicator and the dynamic load indicator in order to determine the ratio of the tangential force applied to the ground by the wheel under the action of said torque to the normal force applied to the ground by the wheel under the action of the dynamic load. One or more tests of the value of the duly calculated road grip coefficient are used to validate the ability of a measurement of the corresponding circumferential wheel speed to supply an adequate approximation of the speed of advance of the vehicle in the position of that wheel.
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Citations
21 Claims
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1-10. -10. (canceled)
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11. System for determining an estimation of an instantaneous speed of a vehicle relative to a ground surface based on measurements obtained from a movement sensor for a wheel of the vehicle, the system comprising:
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an indicator of a circumferential wheel speed of a wheel of a vehicle based on measurements from a movement sensor for the wheel; a test stage for validating an indication of the circumferential wheel speed at an output of the indicator in order to deduce therefrom a reliable representation of a speed of advance of the vehicle according to at least one predetermined criterion; a speed estimation module suitable for combining circumferential wheel speed indications validated by the test stage to supply an estimation of the speed of advance of the vehicle relative to the ground surface; a device for calculating an instantaneous road grip coefficient of the wheel based on data available on board the vehicle, wherein the test stage is suitable for testing a value of the road grip coefficient obtained for the wheel, according to a relationship that enables determination of whether a corresponding difference, or slip, between the circumferential wheel speed of the wheel and the speed of advance of the vehicle relative to the ground surface at a given instant is sufficiently small for the circumferential wheel speed to be able to be retained by the speed estimation module as a datum for determining the estimation of the speed of advance of the vehicle relative to the ground surface. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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Specification