Jtekt Europe

Jtekt Corporation

Jtekt Europe S.a.s.

Pascal Moulaire

Christophe Ravier

Sébastien Bourdrez

André Michelis

Tahar Slama

Pierre Larminy

Serge Gaudin

Terutaka Tamaizumi

Nicolas Baudouin

Pierre Pilaz

Stephane Cassar

Dimitri Barthes

Kazusa Yamamoto

Arnaud Thiery

Julien Barthomeuf

Andre Michelis

Jean-Marc Kasbarian

Alain Guilemond

Romaric Pregniard

Pierre-Willem Pilaz

Pierre Dupraz

Ofaina Taofifenua

Julien Ponte

Hervé Peltier

Sebastien Herault

Quentin Fraison

Yoann Baudin

Stéphane Cassar

Sébastien Herault

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 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 method in which a continuous estimation of the intermediate friction rate is carried out, allowing the integration of the method into a general friction compensation method so as to continuously improve the feel on the steering wheel, particularly for speeds below a determined threshold. Also, a method for friction compensation in an electrical power steering system, characterised in that the compensation method takes into account a continuous estimation of the intermediate friction rate obtained by the estimation method.

Method for friction compensation in a power steering system and associated estimation method

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 power-steering system for a motor vehicle includes a steering wheel and an assistance motor controlled by a closed-loop regulation system, the regulation system determining a motor torque of the assistance motor as a function of a measured steering-wheel torque, using at least one 'setpoint monitoring' arm calculating a component of the motor torque, referred to as 'variant motor torque', by subtracting a set steering-wheel torque from the RFe corresponding to the sum of the measured steering-wheel torque and the motor torque, wherein the variant motor torque is multiplied by a gain determined by a three-dimensional map as a function of a vehicle speed and the measured steering-wheel torque.

Perception of a road profile by the varying a gain as a function of a vehicle speed and steering wheel torque

A steering controller includes processing circuitry configured to execute a first operation process that, when an angle command value is not input from outside of the processing circuitry, calculates a first torque command value corresponding to a steering-side operation amount and operating a drive circuit of an electric motor to adjust torque of the electric motor to the first torque command value. The processing circuitry is further configured to execute a second operation process that, when the angle command value is input from the outside of the processing circuitry, calculates a second torque command value corresponding to at least an angle-side operation amount of the steering-side operation amount and the angle-side operation amount and operating the drive circuit of the electric motor to adjust the torque of the electric motor to the second torque command value.

Steering controller and steering control method

A method for managing a power steering system assist motor, includes defining, over the functional length of the actuator member, at least one reduced assist area separate from a normal assist area by an end-of-travel virtual threshold, a step of assessing an instantaneous position and a direction of the movement of the actuator member on the functional length, a step of applying an input resistance set point value to the assist motor when the actuator member crosses the end-of-travel virtual threshold in such a way as to move from the normal assist area into the reduced assist area. After the step of applying an input resistance set point value, an output resistance set point value is applied when the actuator member is in the reduced assist area and the direction of the movement of the actuator member is directed from the reduced assist area towards the normal assist area.

Differentiation of a resisting torque according to direction of movement of a steering rack for improving feel of driver at the approach to an end-of-travel virtual stop

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 steering controller includes processing circuitry. The processing circuitry is configured to execute an operation process for calculating a torque command value corresponding to a sum of an amount by which the steering-side operation amount is converted into the torque required for the electric motor and an amount by which the steerable wheel-side operation amount is converted into the torque required for the electric motor and operate a drive circuit of the electric motor to adjust the torque of the electric motor to the torque command value.

A power steering system including a steering wheel, a return function to automatically return the steering wheel to a given reference position, and includes a function for calculating a return-speed setpoint which calculates a steering wheel speed setpoint from the steering wheel position error differentiating between the effective instantaneous position of the steering wheel and the reference position, then a function for calculating the return assistance, defining from the steering wheel speed error which is the difference between the effective speed of the steering wheel and the steering wheel speed setpoint, a return assistance setpoint, the system including a dynamic saturation function defining at least one saturation threshold, that the dynamic saturation function sets according to the value of the steering wheel speed setpoint, and the dynamic saturation function applies to clip the peaks of the return assistance setpoint calculation to confine the return assistance setpoint to an authorized domain.

Use of a dynamic saturation function when returning a steering wheel to its central position, so as to eliminate undesirable viscous effects

A steer-by-wire power steering system including a lower-level mechanism that includes a servo motor and a steered wheel, and an upper-level mechanism that includes a steering wheel and an auxiliary motor, the lower-level mechanism being closed-loop controlled, at zero force, by a lower local loop including a feedback branch that measures or estimates an actual downstream force downstream of the servo motor and upstream of the point of contact between the wheel and the ground, so as to make the servo motor transparent, while the upper-level mechanism is closed-loop controlled, at zero torque, by an upper local loop including a feedback branch which measures or estimates an actual driver torque between the auxiliary motor and the steering wheel so as to make the auxiliary motor transparent, the lower and upper local loops being controlled by a single overall controller.

Steer-by-wire power steering system using actuators made transparent through the use of local torque and/or force control loops

A steering controller includes processing circuitry configured to execute a torque control process that calculates a steering-side operation amount, an angle feedback control process that calculates an angle-side operation amount, and an operation process that operates a drive circuit of an electric motor to adjust torque of the electric motor to a torque command value. The processing circuitry is further configured to execute a switch process that switches, when determining that a controllability of the electric motor is less than or equal to a predetermined efficiency, the torque command value from a value based on the angle-side operation amount to a value based on the steering-side operation amount instead of the angle-side operation amount.

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

A method for controlling a power steering device including a steering assist motor and a steering wheel. In the method, a steering wheel torque setpoint is generated, the actual steering wheel torque actually exerted by the driver on the steering wheel is measured, the difference, the so-called 'steering wheel torque error', between the steering wheel torque setpoint and the actual steering wheel torque is determined, then a motor torque setpoint for the steering assist motor is generated from a first filtered proportional component on one hand, obtained by filtering via a phase-lead filter the steering wheel torque error weighted by a first assist gain, and from a second derivative return component on the other hand, obtained by calculating the time derivative of the actual steering wheel torque and weighting the derivative by means of a second derivative gain.

Use of a phase-lead filter to separate the manual steering setting from the power steering control stability setting

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.

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La Tour de Salvagny, France

Pascal Moulaire