Jtekt Europe

Serge Gaudin

Pascal Moulaire

Kazusa Yamamoto

André Michelis

Sébastien Bourdrez

Nicolas Baudouin

Andre Michelis

Pierre Pilaz

Pierre Dupraz

Yoann Baudin

Ofaina Taofifenua

A method for estimating a value of a friction force exerted on a part of a power steering system of a vehicle, the part of the power steering system including at least one motor exerting a motor torque, the value of the friction force making it possible to modify the motor torque, by means of a mathematical model.

Method for estimating a value of a friction force exerted on a part of a power steering system by means of a mathematical model

A power-steering device includes a steering wheel and an assistance motor controlled by a controller which uses at least one closed-loop control law ensuring an adjustment of the steering wheel torque, the controller including at least one feedback arm which calculates a drift component by measuring or assessing an actual force parameter corresponding to the actual steering wheel torque, by next calculating a time drift value of the actual force parameter, and then multiplying the time drift value by a drift gain, wherein the controller uses three-dimensional cartography to adjust the drift gain according to a portion of the actual force parameter and the longitudinal velocity of the vehicle, according to a first domain, referred to as 'parking domain', which extends from a longitudinal vehicle velocity of zero to a predetermined longitudinal velocity threshold, and a second domain, referred to as 'driving domain', which extends beyond the longitudinal velocity threshold.

Adaptation of a drift gain according to steering wheel torque in order to improve the feel of a power-steering system

A method estimates a track rod force which is exerted, in a power steering system with which a vehicle is equipped, on a track rod belonging to a steering mechanism which connects an actuator to a steered wheel which is orientable in the yaw direction and which bears a tyre of which the tread is in contact with the ground, the value of the estimated track rod force being corrected as a function of the longitudinal speed of the vehicle by a force component that models the release of the elastic torsion of the tyre so as to reduce, the estimated track rod force according to the longitudinal speed of the vehicle, when the vehicle transitions from a park situation in which the longitudinal speed of the vehicle is zero to a drive situation in which the longitudinal speed of the vehicle is non-zero.

Method for determining the track rod force modeling the torsional elastic release of the tyre in order to manage transitions between park and drive

The invention relates to a method for managing an assisted steering device () for a vehicle () comprising a steering wheel () on which the driver exerts a manoeuvring effort, termed the 'steering wheel torque' (T), as well as an assistance motor () intended to provide an assistance effort (T), said method comprising a steering wheel torque reconstruction step (a) in the course of which the steering wheel torque (T) is evaluated, such as is actually exerted by the driver on the steering wheel (), without calling upon a steering wheel torque sensor () specifically dedicated to the measurement of said steering wheel torque, but by reconstructing an information item representative of said steering wheel torque (T), termed the 'estimated steering wheel torque' (T_estim), on the basis of data termed &#x201c;external data&#x201d; () that is gathered outside a specific steering wheel torque sensor () such as this and which include the angular position of the steering wheel (), the angular position () of the shaft of the assistance motor (), and the time derivatives () of these angular positions.

Method of managing assisted steering with indirect reconstruction of the steering wheel torque information

The invention relates to a power steering system in which the set value for torque or force at the steering wheel is predetermined on the basis of various parameters and information so as to provide the most driving comfort in all conditions of driving the vehicle. The torque or force set value is predetermined on the basis of the sideways acceleration of the vehicle, the acceleration in turn being predetermined mainly from an estimate of the force exerted on the rack, and preferably also predetermined by other methods, with the estimate being weighted among all of the obtained values. Said method is particularly useful for vehicles provided with electrical power steering.

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Saint Jean de Touslas, France

Serge Gaudin