Jtekt Europe

André Michelis

Pascal Moulaire

Pierre Larminy

Christophe Ravier

Luc Leydier

Serge Gaudin

Julien Barthomeuf

Pierre Pilaz

Dimitri Barthes

Fabrice Nobili

Guillaume Lengrais

Stéphane Bourbon

Jocelyn Delarche

Quentin Fraison

François Gassmann

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 fine-tuning a variable-gear steering column according to a speed of the vehicle, the method includes: a step of characterizing a desired handling of the vehicle for a speed Vand of characterizing a desired stability for a speed V; a step of determining a value Gof the gear ratio allowing obtaining the desired handling at the speed V, and a value Gof the gear ratio allowing obtaining the desired stability at the speed V, a step of calculating a parameter pand a parameter paccording to the speed V, the speed V, the value Gand the value Gso that the relationship between the gear ratio and the speed of the vehicle is defined by the equation G=p+p/V, when the speed is included between a first threshold and a second threshold.

Method for fine-tuning a variable-gear steering column, and vehicle comprising a variable-gear power steering system

A method for piloting a motor of a power steering system of a vehicle, the power steering system having at least one steering wheel and one rack, the motor being piloted by a closed-loop proportional-derivative regulator (R) receiving as input an angular position (θ) of the motor and a setpoint angle (θ), the regulator (R) determining a setpoint motor torque (C). The method

Method for piloting a motor by a proportional-derivative regulator taking into account the stiffness of a power steering system

A method for estimating the absolute angular position of a steering wheel equipping a power-steering device, referred to as 'relative steering wheel position', of the shaft of a power-steering motor is assessed, a first estimation (Angle) of the absolute angular position of the steering wheel is assessed from at least one first model using the speed difference between the left and right rear wheels, a first dynamic offset equal to the difference between the first estimation (Angle) of the absolute angular position of the steering wheel and the relative steering wheel position is estimated, and the absolute angular position of the steering wheel is calculated by adding to the relative steering wheel position a total compensation offset determined from the first dynamic offset, also when restarting the vehicle, a switching-off offset corresponds to the value of the total compensation offset at the time when the vehicle was previously switched off.

Assessment of the absolute angular position of a steering wheel by considering its situation when switching off the vehicle

A method for modulating an assistance function application of an assisted steering system in a vehicle, the vehicle including at least two wheels, a steering wheel and an assistance motor applying an assistance torque on a rack, the method implementing a step of evaluating an application gain of the assistance function, a step of estimating the assistance torque associated with the assistance function and a step of multiplying the assistance torque associated with the assistance function and the application gain, characterised in that the step of evaluating the application gain includes a first phase of determining a first gain depending on a yaw speed and an angle of the steering wheel.

Weighting of an assistance function application in an assisted steering system of a vehicle

A method for the gradual activation and deactivation of a steering return function in a vehicle, the vehicle including at least two wheels, a steering wheel, an assist motor applying an assist torque to a steering rack, and a drive motor applying a wheel torque to the wheels, the method including a step of calculating an application gain including a first phase of determining a first gain dependent on the wheel torque of at least one of the two wheels, a step of estimating the assist torque associated with the return function, and a step of multiplying the assist torque associated with the return function and the application gain, wherein during the application gain calculation step the method also includes a second phase of determining a second gain dependent on the angle of the steering wheel and the difference in the rotation speeds of the at least two wheels.

Gradual detection of the appearance of torque steer

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 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 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 power steering device for an axle assembly provided with a limited-slip differential designed to transmit a drive torque to a first and second wheel and to automatically activate, in the event of a loss of synchronism and/or of grip of one of the first and second wheels, an operating mode referred to as 'lockup mode' in which differential transfers most of the driving torque to the slower of the first and second wheels, the power steering also including a steering mechanism and a power steering motor controlled by a control module, steering control module containing compensation laws which allow the power steering motor to compensate for certain effects, such as alternating load backup or freezing, induced in the steering mechanism by activation of the differential lockup mode, so as to give the driver a feel close to that of an axle assembly that does not have a lockup mode.

Use of the power steering to compensate for the negative effects introduced by a limited slip differential

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

A method for determining the absolute angular position of a steering wheel of an electric power-assisted steering column of a motor vehicle, including a means for measuring a dynamic parameter while the vehicle is running and including among others, the steps of periodically determining a multi-turn relative angular position, determining at least one dynamic parameter relating to the running conditions of the vehicle using the means for measuring said parameter, determining an absolute steering-wheel angle calculated according to at least one dynamic parameter, and weighting the calculated value of the absolute steering-wheel angle according to a test of the validity of the calculated value of the absolute steering-wheel angle and the origin of said value, in other words, the measurement means used to determine said at least one dynamic parameter.

Device for determining the absolute angular position of the steering wheel of an electric power-assisted steering column of a motor vehicle using weighted dynamic parameters of the vehicle

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Chonas l'Amballan, France

André Michelis