초록 ▼

A method and device, using fuzzy logic, to control the value of a braking torque of a wheel of a vehicle applied to a track, the input variables being the coefficient of slippage of the wheel on the track, the first derivative of this coefficient with respect to time, the derivative of the braking t

A method and device, using fuzzy logic, to control the value of a braking torque of a wheel of a vehicle applied to a track, the input variables being the coefficient of slippage of the wheel on the track, the first derivative of this coefficient with respect to time, the derivative of the braking torque with respect to the slippage and the value of the braking torque, the output variable being an algebraic increase of the braking torque. Application to wheeled vehicles.

대표청구항 ▼

A method to control the value of a braking torque of a wheel that is rotationally linked to a vehicle applying the wheel to the road on a track, the forces of adherence between the wheel and the track being capable of prompting a rotation torque of the wheel that counters the braking torque, the max

A method to control the value of a braking torque of a wheel that is rotationally linked to a vehicle applying the wheel to the road on a track, the forces of adherence between the wheel and the track being capable of prompting a rotation torque of the wheel that counters the braking torque, the maximum value of which is, at each instant, a function of a coefficient of slippage (g) of the wheel on the track, it being possible to represent the value of this maximum as a function of the coefficient of slippage by a curve of adherence itself having, at a point (c), a maximum (M) for a value (g0) of the slippage coefficient, the method comprising: iterative computation, according to the principles of fuzzy logic, of an output magnitude representing an algebraic increase of a preceding value of the braking torque, this increase being added to the preceding value of the braking torque to determine a corrected value of the braking torque, a first value of the torque being constituted by a control value, the computation being done on the basis of three input magnitudes comprising the value of the coefficient of slippage of the wheel on the track, a slope magnitude (s) representing the derivative of the braking torque with respect to the slippage, a magnitude (dgliss) being the first derivative of the slippage with respect to time; comparison of the corrected value of the braking torque with the control value of this torque; limiting, if necessary, of the last increase computed so that a computed value of the torque resulting from the addition of the computed increase, possibly limited, is at most equal to the control value; application of the computed value to a braking device, said operations of computation, comparison, limiting if necessary and application taking place at the end of a phase preliminary to the use of the method, comprising: fixing, for each input magnitude, of a number of continuous qualitative ranges and of a number of continuous qualitative zones for the output magnitude, each of the ranges or zones comprising all the values extending from a minimum value to a maximum value, these two values constituting the limits of the range or zone; assigning of a coefficient of membership ranging from 1 to 0 to each value of each range or zone; assigning, to each combination of three ranges that can be constituted with a range of each of the input values, of a number identifying one of the qualitative zones of the output value assigning, to each zone, of the output value of a weight which is a magnitude proportional to a surface demarcated by a segment whose length is equal to the length of the zone, by a curve representing, in a direction perpendicular to the segment, the value of the coefficient of membership in the zone of each value of the segment and, possibly, by perpendiculars to the segment that are taken to its ends; and defining of a rule to determine a quantified output value from qualitative zones designated by each of the combinations that can be constituted with a range to which there belongs each of the three input values, measured during the subsequent performance of the method, the rule stipulating that the quantified value is a function of the weight of each of the designated zones and, for each of them, a function of a coefficient of weight which is itself a function of the coefficients of membership of each real measured value in the range participating in the combination that designates the output qualitative zone.