Jtekt Europe

Christophe Ravier

Pascal Moulaire

Sébastien Bourdrez

André Michelis

Romaric Pregniard

Pierre Larminy

Andre Michelis

Pierre Pilaz

Xavier Palandre

Jocelyn Delarche

Loïc Bastien

Stéphane Cassar

A method for determining a setpoint torque for a steering wheel of an electric power steering system of a vehicle, the setpoint torque helping determine an engine torque applied directly or indirectly to the steering wheel, the setpoint torque being a function of at least one equivalent lateral acceleration having a dimension of an acceleration, wherein the equivalent lateral acceleration is weighted by a gain dependent on at least a steering wheel torque.

Method for determining a setpoint torque for a steering wheel as a function of a gain dependent on a steering wheel torque

A method for determining a setpoint torque for a steering wheel of a power-assisted steering system of a vehicle, the setpoint torque making it possible to determine a motor torque applied directly or indirectly by a control motor to the steering wheel, and the setpoint torque being at least determined by a reversibility function designed to bring a steering wheel angle of the steering wheel toward the steering wheel angle at which the vehicle will follow a trajectory in a straight line, the reversibility function comprising a first step in which a target speed of the steering wheel is determined depending on the steering wheel angle, wherein the target speed is also a function of a yaw rate of the vehicle.

Method for determining a setpoint torque on the basis of a reversibility function calculating a target speed of a steering wheel depending on a steering wheel angle and a yaw rate

A method for estimating the ageing of a steering mechanism during which the ageing of the steering mechanism is assessed by calculating a value called &#xab;ageing value&#xbb; according to an ageing function (old, old2, ene) which corresponds to the integral, over time, of an expression which is weighted by a stress indicator (T(u), T(u)) the value of which at each considered instant (u) is representative of the intensity of a stress force (T, T), such as the operating force exerted by the assist motor, which is undergone by the steering mechanism at the considered instant.

Estimation of the ageing of a power steering

A method for detecting a situation of loss of grip of a vehicle provided with a steering system operated by a steering wheel, the method including a step (a) of evaluating a first indicator of loss of grip (P) by calculating, as the first indicator of loss of grip (P), the partial derivative relative to a variable (&#x3b1;) representative of the angular position of the steering wheel, of a driving parameter which is representative of the yaw rate ({dot over (&#x3c8;)}) of the vehicle.

Understeer and oversteer detector for a motor vehicle

The invention concerns a method for detecting a transition (') in a noisy signal, which involves submitting a noisy signal (&#x3b4;Signal) carrying an item of information used for managing the power steering, said method comprising a derivation sub-step (a), which involves evaluating the time derivative of the noisy signal (&#x3b4;Signal/&#x3b4;t), following by a selective filtering sub-step (a) which involves comparing said time derivative of the noisy signal (&#x3b4;Signal/&#x3b4;t) with a predefined variation threshold (S) in order to detect the appearance of a derivative peak (), greater than said variation threshold (Spic), evaluating the holding time (dpic) of said derivative peak, during which the time derivative of the noisy signal (&#x3b4;Signal/&#x3b4;t) is held above said variation threshold (Spic), and checking if said peak holding time (Spic) reaches or exceeds a predefined minimum time threshold (d).

Filtering method for the detection of the transitions of a power steering signal

A method for managing a power steering system, including a step (a) of detecting a reversal in the steering direction which involves acquiring a signal, referred to as a 'motor torque signal' (C), representative of the assistance force (C) delivered by the power steering motor, then evaluating the time derivative (&#x3b4;C/&#x3b4;t) of the motor torque signal, then comparing the time derivative of the motor torque signal to a predefined variation threshold (S) in order to detect a derivative peak, greater than the variation threshold (S), that indicates a reversal in the steering direction. The method next includes a friction evaluation step (b) which involves evaluating the friction from the drop, during the reversal in the steering direction, in a so-called 'actuation force signal' (C), which is representative of the total actuation force exerted together on the power steering by the driver and by the power steering motor.

Detection method of a steering reversal by monitoring of the torque provided by a steering assist motor and application of said method for evaluating the friction

The present invention concerns a method for determining the position of a movable steering member () belonging to a steering mechanism () of a vehicle that comprises at least a first movable member (), such as a shaft () of an assistance motor (M), and a second movable member (), such as a rack (), which cooperate with each other by means of at least one first link (L), said method comprising a step (a) that involves measuring the position (&#x3b8;) of the first member (), then a step (b) that involves calculating the instantaneous position (&#x3b8;) of the second member () from said position of the first member (&#x3b8;), and a correction step (d) during which the calculation of the position (&#x3b8;) of the second member () is adapted, taking into consideration the offset (&#x3b4;&#x3b8;&#x3c5;) in the position of the second member () that results from the elastic deformation of the first link (L) under the force (C) transmitted by the latter.

Method for calculating, in real time, the absolute position of a power steering member with improved accuracy

A method for evaluating the frictions in a power steering mechanism, the method including a step of acquiring a series of characterization points, during which are measured, for several different values taken successively by the assistance force during the operation of the steering mechanism, the corresponding friction values, so as to empirically obtain a series of distinct characterization points each associating a measured friction value to a measured value representative of the assistance force, then a step of constructing an empirical friction model, during which a correlation law is established between the characterization points constitutive of the series of characterization points, from the scatter chart formed by the series of the characterization points.

Modelling of frictions in a power steering system using a scatter of points

A method determines a link force within a power-steering mechanism of a vehicle, the method including a step (a) of determining an actuation force, which involves determining the actuation force that results from the assistance force exerted by the assistance motor and the driver force exerted by the driver of the vehicle on the steering mechanism; a step (b) of assessing dry friction; and a step (c) of calculating the link force, which has a summation sub-step which involves calculating an expression representing the link force, which uses the algebraic sum of the actuation force and the dry friction force, and a filtering sub-step which involves applying a low-pass filter in order to smooth the result of the expression when the expression is calculated upon a steering reversal of the steering mechanism.

Method for estimating in real time the force on the tie-rods within a power steering mechanism

A reference position in a power steering system is defined by acquiring a first edge position corresponding to a first edge of a first index pulse generated when a movable steering member passes an indexed position in a first movement direction; acquiring a second edge position corresponding to a second edge of a second index pulse generated when the movable steering member passes the same indexed position in a second movement position opposite the first movement direction; and calculating the reference position from the first edge position and the second edge position.

Determination of an angular reference position of a power steering system from rising and falling edges of an index signal

A method for securing the assistance torque () supplied by an electric assistance motor () in a motor vehicle power steering system includes the steps of: estimating the force on the steering system rack from the torque exerted by the driver on the steering wheel (), from the assistance torque (), and optionally from other parameters such as the speed of the electric assistance motor; comparing a target assistance torque with an authorized assistance range, defined with respect to the estimated rack force () at any moment, and in the event the target assistance torque is maintained above predefined limits for a predefined duration, correcting and optionally interrupting the power steering.

Growing community of inventors

Saint Pierre de Chandieu, France

Christophe Ravier