Differentiate the resistance torque based on the direction of movement of the steering rack to improve the driver's feel when approaching a virtual stop near the end of its travel.

Abstract

The present invention relates to a method for managing an auxiliary motor (M) of a power-assisted steering system (1) of a vehicle, the steering system including an actuator (4) that performs movement along a functional length (LO), the method comprising: defining at least one reduced assist region (ZAR) along the functional length (LO) of the actuator (4). D ZAR G The step of reducing the auxiliary region is achieved through the virtual journey end threshold (S). G S D The steps include: separating the actuator (4) from the normal auxiliary region (ZAN); evaluating the instantaneous position and direction of motion (D) of the actuator (4) in the functional length (LO); and when the actuator (4) moves from the normal auxiliary region (ZAN) to the reduced auxiliary region (ZAR). D ZAR G The virtual journey endpoint threshold (S) is crossed in a way that allows the virtual journey endpoint to be reached. G S D When applying the input resistance setpoint value (C) to the auxiliary motor (M), resistant The step, characterized in that, at the applied input resistance setpoint value (C) resistant After the step of ), when the actuator (4) is in the reduction auxiliary region (ZAR) D ZAR G The direction of motion (D) of the actuator (4) is from the reduced auxiliary region (ZAR). D ZAR G When moving towards the normal auxiliary region (ZAN), apply the output resistance setpoint value (C). resistant ).

Description

Technical Field

[0001] This invention relates to the field of power steering systems for vehicles, and more specifically, to a method for managing an auxiliary motor of a vehicle's power steering system. Background Technology

[0002] The vehicle's steering system is used to enable the driver to control the vehicle's trajectory by applying force to the steering components (usually corresponding to the steering wheel).

[0003] Traditionally, a steering system includes several elements, including the steering member coupled to the steering column, an actuator member such as a rack, and at least one steered member (such as a wheel) coupled to a tie rod. The actuator member is the component that allows the steering member to be coupled via the steering column to the steered member via the tie rod; in other words, the rack converts the force applied by the driver to the steering member into steering of the steered member.

[0004] The vehicle's power steering system involves an auxiliary motor operated by an auxiliary setpoint issued by a steering calculator to reduce the force applied by the driver to the steering member in order to steer at least one of the steering members of the vehicle. Based on the force applied to the steering member (i.e., the steering force), the auxiliary motor applies an auxiliary force (i.e., the motor force) on the rack, thereby steering the steering member.

[0005] The actuator component can translate over a functional length corresponding to a maximum displacement defined between the maximum position on the right and the maximum position on the left. This functional length can be physically limited by a mechanical stop, or virtually limited by a virtual setpoint for the end of the stroke as described in the applicant's patent EP3003823.

[0006] The virtual threshold at the end of the stroke determines a deceleration threshold contained in the functional length. Exceeding this threshold, the auxiliary setpoint is modified to become a resistance setpoint value intended to prevent the actuator component from advancing in the overtaking direction. Therefore, a normal auxiliary region and at least one reduced auxiliary region are defined in the functional length, in which the resistance setpoint value is applied to the auxiliary motor.

[0007] It is known that the resistance setpoint value is obtained by applying an expression that includes an elastic component simulating the spring effect, and / or a viscous component simulating the damper effect, and / or an inertial component simulating the effect of movable mass. The elastic, viscous, and inertial components are proportional to the stiffness coefficient, viscosity coefficient, and inertia coefficient, respectively.

[0008] The stroke end virtual threshold allows the use of an auxiliary motor to slow down and stop the actuator component in the direction of the stroke end virtual threshold to prevent it from exceeding the limit stop threshold in the functional length.

[0009] The advantage provided by this virtual threshold at the end of the stroke is, in particular, the avoidance of mechanical contact between the actuator component and the mechanical stop, which allows the manufacturer to improve the driver's feel on the level of the steering component as the actuator component enters and leaves the reduction assist area. Summary of the Invention

[0010] The purpose of this invention is to improve the driver's feel in the reduction assist zone by distinguishing the resistance setpoint value between the input resistance setpoint value and the output resistance setpoint value in the reduction assist zone.

[0011] The present invention provides a method for managing an auxiliary motor in a vehicle's power steering system, the power steering system including an actuator component that performs movement along a functional length, the method comprising:

[0012] - A step of defining at least one reduced auxiliary region over the functional length of the actuator component, said reduced auxiliary region being separated from the normal auxiliary region by a virtual threshold at the end of the stroke.

[0013] - Steps for evaluating the instantaneous position and direction of motion of the actuator components along the functional length.

[0014] - The step of applying an input resistance setpoint value to the auxiliary motor when the actuator component crosses the virtual threshold of the stroke end in such a manner as it moves from the normal auxiliary region to the reduced auxiliary region.

[0015] The characteristic feature is that, after the step of applying the input resistance setpoint value, when the actuator member is in the reduced auxiliary region and the direction of movement of the actuator member is from the reduced auxiliary region to the normal auxiliary region, the output resistance setpoint value is applied.

[0016] The power steering system includes a steering member coupled to a steering column, an actuator member, and at least one steering member coupled to a tie rod. The actuator member is a component that allows the steering member to be coupled via the steering column to the steering member via the tie rod.

[0017] The power steering system of a vehicle involves an auxiliary motor to reduce the force exerted by the driver on the steering member to steer the vehicle's steered component. Based on the force applied to the steering member (that is, the steering force), the auxiliary motor applies an auxiliary force on the actuator component to steer the steered component.

[0018] In this power steering system, the actuator component performs translational motion along a functional length. Typically, the actuator component is a rack, and the functional length is the steering housing.

[0019] The step of defining at least one reduced auxiliary region (which is separated from the normal auxiliary region by a virtual threshold at the end of the stroke) allows defining at least one first range and one second range of the functional length, in which the set point of the auxiliary force provided by the auxiliary motor is distinguished.

[0020] In the normal assistance range, the set point of the assistance force is determined by an assistance law in a manner known to those skilled in the art, the assistance law being particularly dependent on vehicle data and power steering system data.

[0021] In reducing the auxiliary region, the set point of the auxiliary force is determined in order to slow down and stop the actuator component from moving forward in the direction of passing the virtual threshold of the end of the stroke.

[0022] Preferably, the normal auxiliary region is located substantially in the middle of the functional length.

[0023] Preferably, the reduced auxiliary region is located substantially at one end of the functional length.

[0024] According to one embodiment, the functional length includes two decreasing auxiliary regions symmetrically located on either side of a central position corresponding to a position where the steering component is aligned with the extended axis of the vehicle.

[0025] The steps of evaluating the instantaneous position and direction of motion of the actuator component along the functional length determine the characteristics of the translational motion of the actuator component.

[0026] More specifically, the instantaneous position can be indiscriminately defined by any representative parameter of the position of the actuator component relative to the functional length, such as by any measurement or evaluation of the absolute angular position of the steering component, the absolute angular position of the steering column, or the absolute angular position of the shaft of the auxiliary motor.

[0027] Furthermore, the movement of the actuator component is carried out along the extended axis of the functional length, and the direction of movement is either in a first direction along the extended axis of the functional length or in the opposite direction.

[0028] When the actuator component is in the reduced auxiliary region, the movement of the actuator component from the normal auxiliary region to the reduced auxiliary region will be referred to as the entry movement.

[0029] When the actuator component is in the reduced auxiliary region, the movement of the actuator component from the reduced auxiliary region to the normal auxiliary region will be referred to as the exit movement.

[0030] The step of applying the input resistance setpoint value includes applying the input resistance setpoint value to the auxiliary motor when the actuator component performs an entry motion.

[0031] An input resistance setpoint value is determined such that the force provided by an auxiliary motor resists the movement of the actuator component. This auxiliary motor applies an auxiliary force directly to the actuator component, or indirectly, i.e., the motor force is applied to the steering column, for example, via a worm gear reducer. Specifically, the input resistance setpoint value allows for slowing down the movement of the actuator component. The value of the input resistance setpoint is determined such that the actuator component never reaches a stop threshold located at a predetermined distance from the virtual threshold at the end of the stroke within the reduced assistance zone.

[0032] The stop threshold can be a virtual threshold or, for example, a real mechanical stop located at one end of the functional length. Therefore, the input resistance setpoint value maintains mechanical contact between the actuator component and the mechanical stop.

[0033] Preferably, the input resistance setpoint value is determined so that the driver has an accurate and intuitive feel for the predictable behavior of the actuator components in contact with the mechanical stop.

[0034] In short, during driver steering, the actuator component, initially located in the normal assist zone, crosses the virtual end-of-stroke threshold and then approaches the stop threshold in a decelerating manner until its movement in the direction of the stop threshold comes to a complete stop. That is, when the actuator component performs movement in the direction of the reduced assist zone, it crosses the virtual end-of-stroke threshold and then stops its movement, so that it never comes into contact with the stop threshold.

[0035] The step of applying the output resistance setpoint value includes applying the output resistance setpoint value to the auxiliary motor when the actuator component performs an exit motion.

[0036] After the entry motion has been performed, the actuator component continues its motion in the opposite direction to the previous direction, that is, it performs the exit motion.

[0037] The output resistance setpoint value has a different value than the input resistance setpoint value. Determining the output resistance setpoint value allows the force provided by the auxiliary motor to give the driver an accurate and intuitive feel for the predictable behavior of the actuator components after contact with the mechanical stop.

[0038] Preferably, the input resistance setpoint and output resistance setpoint are parameterized so that the driver has an accurate and intuitive feel for the predictable behavior of the actuator components during contact with a mechanical damper with variable compression / expansion damping.

[0039] The embodiments of the present invention are implemented by programming a calculator that operates the auxiliary motor. Therefore, the present invention can be applied, for example, as an accessory to most power steering systems in vehicles already in circulation.

[0040] According to the features of the present invention, the output resistance setpoint value includes:

[0041] - The exit elastic component, which is proportional to the exit stiffness coefficient and the amplitude of motion of the actuator components, and

[0042] - The exit viscous component is proportional to the exit viscosity coefficient and the velocity of the actuator components.

[0043] The exit elastic component allows for the simulation of a spring effect. The exit elastic component is proportional to a predetermined exit stiffness coefficient corresponding to the spring stiffness and also proportional to the amplitude of motion of the actuator component in the reduction auxiliary region. The motion of the actuator component is a translation along an axis represented by the functional length.

[0044] The exit elastic component allows for a continuous feel for the driver between entering and exiting a motion. However, it can cause a strong rebound effect by returning energy to the actuator components.

[0045] The exit viscous component allows for the simulation of damper effects. The exit viscous component is proportional to a predetermined exit viscosity coefficient and also proportional to the velocity of the actuator component within the reduced auxiliary region. The velocity of the actuator component is a linear velocity, corresponding to the first derivative of the instantaneous position with respect to time, or, equivalently, the first derivative of the motion amplitude with respect to time. For example, the velocity of the actuator component can be evaluated by measuring the angular velocity of the steering component or the shaft of the auxiliary motor.

[0046] Withdrawing the viscous component allows for a reduction in energy return to the actuator components by withdrawing the elastic component. In other words, the viscous component limits the rebound effect caused by withdrawing the elastic component.

[0047] As those skilled in the art will know, the output resistance setpoint value is therefore obtained, after the spring-damper type abutment, by simulating a first-order expression of the effect on the actuator components. This first-order expression corresponds to the response of the actuator components after contact with a stop dummy mechanism, which includes a spring mounted parallel to the viscous linear damper.

[0048] According to the features of the present invention, the output resistance setpoint value includes:

[0049] - The exit elastic component is proportional to the exit stiffness coefficient and the amplitude of motion of the actuator components.

[0050] - The exit viscous component, which is proportional to the exit viscosity coefficient and the velocity of the actuator components, and

[0051] - The exit inertial component is proportional to the exit inertial coefficient and the motion acceleration of the actuator components.

[0052] The exit inertial component allows for the simulation of movable mass effects. The exit inertial component is proportional to a predetermined exit inertia coefficient and to the acceleration of the actuator component's motion in the reduced auxiliary region. The acceleration of the actuator component is a linear acceleration, corresponding to the second derivative of the instantaneous position with respect to time, or, equivalently, the second derivative of the motion amplitude with respect to time. For example, the acceleration of the actuator component can be evaluated by calculating the velocity derivative or the continuous derivative of the actuator component's position, or by evaluating the angular acceleration of the shaft of the steering component or auxiliary motor.

[0053] The removal of the inertial component allows for the simulation of the inertia of the actuator component after it comes into contact with the mechanical stop.

[0054] As those skilled in the art will know, the output resistance setpoint value is thus obtained by simulating a second-order expression of the effect on the actuator components after the mass-spring-damper type is adjacent. This second-order expression allows for a more accurate perception of the effect on the actuator components after contact with the mechanical stop, ensuring a better, more natural, and more intuitive driving experience for the driver.

[0055] According to the features of the present invention, the exit stiffness coefficient and / or exit viscosity coefficient and / or exit inertia coefficient depend on at least one of the following parameters: the displacement velocity of the vehicle equipped with the auxiliary motor, the torque applied by the driver to the steering member, the instantaneous position of the actuator member, the motion amplitude of the actuator member, the motion speed of the actuator member, and the motion acceleration of the actuator member.

[0056] Therefore, the exit stiffness coefficient and / or exit viscosity coefficient and / or exit inertia coefficient are adjusted according to the vehicle's service life. The exit stiffness coefficient and / or exit viscosity coefficient and / or exit inertia coefficient are determined from predetermined charts or curves based on different parameters.

[0057] According to the features of the present invention, the input resistance setpoint value includes:

[0058] - The elastic component enters, which is proportional to the entry stiffness coefficient and the amplitude of motion of the actuator components, and

[0059] - The viscous component enters, which is proportional to the viscosity coefficient and the velocity of the actuator components.

[0060] The entry elastic component allows for the simulation of a spring effect. The entry elastic component is proportional to a predetermined entry stiffness coefficient, corresponding to the stiffness of a spring, and is also proportional to the amplitude of motion of the actuator component in the reduced auxiliary region.

[0061] The entry of the elastic component generates an elastic bias load that counteracts the increased resistance to the push of the actuator component, which is proportional to the motion of the actuator component beyond the virtual threshold of the considered stroke end.

[0062] The entry viscous component allows for the simulation of the damper effect. The entry viscous component is proportional to a predetermined entry viscosity coefficient and also proportional to the velocity of the actuator component in the reduced auxiliary region.

[0063] Entering the viscous component allows for adjustment of the displacement speed of the actuator components, thus preventing the stop threshold from being reached at excessively high speeds. Excessively high speeds would cause the steering force felt by the driver to increase rapidly, which would be abnormal.

[0064] As those skilled in the art will know, the input resistance setpoint value is therefore obtained by simulating a first-order expression for the stopping of a spring-damper.

[0065] According to the features of the present invention, the input resistance setpoint value includes:

[0066] - The elastic component is proportional to the stiffness coefficient and the amplitude of motion of the actuator components.

[0067] - The viscous component enters, which is proportional to the coefficient of viscosity and the velocity of the actuator components, and

[0068] - The inertial component is proportional to the inertial coefficient and the acceleration of the actuator components.

[0069] The inertial component allows for the simulation of movable mass effects. The inertial component is proportional to a predetermined inertial coefficient and also proportional to the acceleration of the actuator component in the reduced-amplitude region.

[0070] Entering the inertial component allows for the simulation of the inertia of actuator components in contact with the mechanical stop.

[0071] As those skilled in the art will know, the input resistance setpoint value is therefore obtained by simulating a second-order expression for mass-spring-damper stop. This second-order expression allows for a more accurate perception of the mechanical stop, ensuring a better, more natural, and more intuitive driving experience for the driver.

[0072] According to the features of the present invention, the entry stiffness coefficient and / or entry viscosity coefficient and / or entry inertia coefficient depend on at least one of the following parameters: the displacement velocity of the vehicle equipped with the auxiliary motor, the torque applied by the driver to the steering member, the instantaneous position of the actuator member, the motion amplitude of the actuator member, the motion velocity of the actuator member, and the motion acceleration of the actuator member.

[0073] Therefore, the entry stiffness coefficient and / or entry viscosity coefficient and / or entry inertia coefficient are adjusted according to the vehicle's service life. The entry stiffness coefficient and / or entry viscosity coefficient and / or entry inertia coefficient are determined from predetermined charts or curves based on different parameters.

[0074] According to the features of the present invention, the at least one virtual threshold for the end of the journey depends on at least one of the following parameters: the displacement speed of the vehicle equipped with the auxiliary motor, the torque applied by the driver to the steering member, the instantaneous position of the actuator member, the amplitude of motion of the actuator member, the speed of motion of the actuator member, and the acceleration of motion of the actuator member.

[0075] Therefore, the implementation strategy (i.e., location) of the virtual threshold for the end of the trip can be adjusted according to the vehicle's lifespan, particularly the activation conditions of the virtual threshold for the end of the trip.

[0076] According to the features of the present invention, the entry viscosity coefficient has a higher value than the exit viscosity coefficient.

[0077] Therefore, the viscosity coefficient is high, which allows for a reduction in the speed of the actuator components.

[0078] According to the features of the present invention, the entry viscosity coefficient was used earlier than the entry stiffness coefficient.

[0079] The exit viscosity coefficient has a low value, more specifically, lower than the entry viscosity coefficient, so as not to excessively resist exit motion.

[0080] According to a feature of the present invention, when the stiffness coefficient is removed, the viscosity coefficient is also removed.

[0081] According to the features of the present invention, the viscosity coefficient is not zero. Attached Figure Description

[0082] The invention will be better understood from the following description, which relates to embodiments of the invention provided as non-limiting examples and explained with reference to the accompanying schematic diagrams, wherein:

[0083] Figure 1 The block diagram illustrates an embodiment for calculating the drag torque according to the present invention;

[0084] Figure 2 The schematic diagram illustrates the positions of the virtual threshold for the end of the journey and the stop threshold along the functional length according to the present invention.

[0085] Figure 3 The diagram illustrates the vehicle's power steering system. Detailed Implementation

[0086] like Figure 3As shown, the power steering system 1 according to the present invention includes a steering member 2 (i.e., a steering wheel 2) connected to a steering column 3, an actuator member 4 (i.e., a rack 4), and two steering members 5 (i.e., two wheels 5) each connected to a tie rod 6. The rack 4 is a component that allows the steering wheel 2 to be connected via the steering column 3 to the wheels 5 via the tie rod 6.

[0087] The vehicle's power steering system 1 involves an auxiliary motor M, which receives a setpoint C. setpoint This set point determines the auxiliary force E to be applied to the rack. A This is to reduce the force applied by the driver to the steering wheel 2 in order to steer the vehicle's wheels 5, that is, the steering force E. D Based on the applied steering force E D The auxiliary motor M applies an auxiliary force E to the rack 4. A This is to turn wheel 5.

[0088] The object of this invention is a method for managing an auxiliary motor M in a power steering system 1, the power steering system including a rack 4 that translates along a functional length L0 (i.e., the steering housing L0), such as... Figure 2 As shown.

[0089] The method includes defining at least one reduced auxiliary region ZAR on the functional length L0 of the actuator component 4. D ZAR G The step of reducing the auxiliary region is through the virtual threshold S at the end of the journey. G S D Separate from the normal auxiliary region ZAN.

[0090] Therefore, including the right end P D and left end P G The functional length L0 is actually divided into a normal auxiliary region ZAN and two reduced auxiliary regions ZAR. D ZAR G .

[0091] Right side P D (correspondingly, the left end P) G This corresponds to a position of rack 4 where rack 4 no longer functions to turn further to the right (and correspondingly to the left) solely through mechanical means.

[0092] In the normal auxiliary region ZAN, which is basically located in the middle of the functional length L0, the setpoint C of the auxiliary motor M is... setpoint Equal to the auxiliary torque C determined by the auxiliary law assist The auxiliary law depends in particular on the vehicle data and the power steering system 1 data.

[0093] At each end P of the functional length L0 D P G Furthermore, the reduced auxiliary region ZAR is symmetrically located on both sides of the center position P0 of the functional length L0. D ZAR G Above, the setpoint C of the auxiliary motor M setpoint Equal to auxiliary torque C assist Subtract the determined resistance torque C resistant To slow down and stop rack 4 as it crosses the virtual threshold S at the end of its travel. G S D Moving forward in that direction.

[0094] The center position P0 is the position of rack 4. At this position, the steering angle of wheel 5 is zero, that is, the wheel is straight, or the wheel is aligned on the front and rear longitudinal axes of the vehicle.

[0095] More specifically, the reduced auxiliary area ZAR on the left. G Located at the left end P of functional length L0 G The reduction auxiliary region on the left is determined by the virtual stop threshold S at the end of the left travel. G Separate from the normal auxiliary region ZAN.

[0096] The right side reduces the auxiliary area ZAR D Located at the right end P of functional length L0 D The reduction auxiliary region on the right is determined by the virtual stop threshold S at the end of the right-hand travel. D Separate from the normal auxiliary region ZAN.

[0097] Virtual threshold S of the journey end D S G Depends on the vehicle's displacement speed and steering force E D The movement amplitude X of rack 4 rack The speed of rack 4 The acceleration of the rack 4

[0098] The method also includes the step of evaluating the instantaneous position and direction of motion D of the actuator component 4 along the functional length L0.

[0099] The movement of rack 4 is along the extension axis of the functional length L0, and the direction of movement D is either in a first direction along the extension axis of the functional length L0 or in the opposite direction. Next, the right-hand direction will be referenced, which corresponds to the reduction of the auxiliary region ZAR allowed from the left. G The reduced auxiliary region ZAR is either moving towards the normal auxiliary region ZAN or moving from the normal auxiliary region ZAN to the right.D The direction of movement. Also referencing the left direction, which corresponds to the reduced auxiliary area ZAR allowed from the right. D The auxiliary region ZAN moves towards the normal auxiliary region or from the normal auxiliary region ZAN moves to the left, reducing the auxiliary region ZAR. G The direction of movement.

[0100] Therefore, when rack 4 is located in the reduced auxiliary area ZAR on the left side G The rack moves to the left during the middle phase, and the auxiliary area ZAR decreases when the rack is on the right side. D The movement of the rack to the right during the middle phase will be referred to as the entry motion later.

[0101] Finally, when rack 4 is located in the reduced auxiliary area ZAR on the left. G The rack moves to the right during the middle phase, and the auxiliary area ZAR decreases when the rack is on the right side. D The leftward movement of the rack during the middle phase will be referred to as the exit movement later.

[0102] The right side reduces the auxiliary area ZAR D And the reduced auxiliary area ZAR on the left G It exhibits symmetrical behavior, and in the following description we will only refer to the right-hand reducing auxiliary region ZAR. D .

[0103] The method according to the invention includes the following steps: when the actuator component 4 moves from the normal auxiliary region ZAN to the reduced auxiliary region ZAR D ZAR G The method to cross the virtual threshold S of the trip end G S D At that time, the input resistance setpoint value C is applied to the auxiliary motor M. resistant .

[0104] Determine the input resistance setpoint value C resistant This makes the auxiliary force E provided by the auxiliary motor M... A The movement of rack 4 is resisted. Specifically, the input resistance setpoint value C is... resistant Allow the movement of rack 4 to be slowed down so that rack 4 never reaches the position corresponding to the right end P at any time. D The right-side stop threshold or the threshold corresponding to the left-side P G The left-side stop threshold.

[0105] When the rack is in the reduction auxiliary area ZAR D During the process, the setpoint C of the auxiliary motor M setpoint Equal to auxiliary torque C assist Subtract the resistance setpoint value C resistant ,like Figure 3 As shown.

[0106] like Figure 1 As shown, the input resistance setpoint value C resistant It is the sum of the following items:

[0107] -Entering the elastic component C E Its relationship with the stiffness coefficient k1 and the motion amplitude X of rack 4 rack Proportional

[0108] - Entering the viscous component C V Its velocity relative to the viscosity coefficient b1 and the speed of movement of rack 4 proportional, and

[0109] -Entering the inertial component C I Its motion acceleration is related to the inertia coefficient m1 and the rack 4. Proportional.

[0110] As those skilled in the art will know, the input resistance setpoint value C resistant Therefore, a second-order expression for simulating mass-spring-damper stopping is obtained. This second-order expression allows for a more accurate perception of the mechanical stop, ensuring a better, more natural, and more intuitive driving experience for the driver.

[0111] The entry stiffness coefficient k1, entry viscosity coefficient b1, and entry inertia coefficient m1 depend on the vehicle's displacement velocity and steering force E. D The movement amplitude X of rack 4 rack The speed of rack 4 The acceleration of the rack 4 The stiffness coefficient k1, viscosity coefficient b1, and inertia coefficient m1 are determined from predetermined charts based on different parameters.

[0112] The method includes the following steps: when the actuator component 4 is in the reduction auxiliary region ZAR D ZAR G Furthermore, the direction of movement D of actuator component 4 decreases from the auxiliary region ZAR. D ZAR G When pointing to the normal auxiliary region ZAN, apply the output resistance setpoint value C. resistant .

[0113] Apply output resistance setpoint value C resistant The steps include applying the output resistance setpoint value C to the auxiliary motor M when the rack 4 performs the exit motion. resistant .

[0114] Output resistance setpoint value C resistant It has the same input resistance setpoint value C resistant Different values.

[0115] like Figure 1 As shown, the output resistance setpoint value is the sum of the following items:

[0116] -Exit elastic component C E Its relationship with the exit stiffness coefficient k2 and the motion amplitude X of rack 4 rack Proportional

[0117] -Exit viscous component C V Its relationship with the exit viscosity coefficient b2 and the speed of movement of rack 4 proportional, and

[0118] - Exit inertial component C I Its relative inertia coefficient m2 and the acceleration of rack 4 Proportional.

[0119] As those skilled in the art will know, the output resistance setpoint value C resistant Therefore, a second-order expression for the effect on the rack is obtained by simulating the effect after the mass-spring-damper type is adjacent. This second-order expression allows for a more accurate perception of the effect on the actuator components after contact with the mechanical stop, ensuring a better, more natural, and more intuitive driving experience for the driver.

[0120] The exit stiffness coefficient k2, exit viscosity coefficient b2, and exit inertia coefficient m2 depend on the vehicle's displacement velocity and steering force E. D The movement amplitude X of rack 4 rack The speed of rack 4 and the acceleration of the rack 4

[0121] The exit stiffness coefficient k2, exit viscosity coefficient b2, and exit inertia coefficient m2 are determined from a predetermined chart based on different parameters.

[0122] When rack 4 is in the normal auxiliary region ZAN, the auxiliary motor M receives an auxiliary torque equal to C. assist Set point C setpoint Then, during the driver's right turn, that is, when the driver applies a steering force E to the right... D At that time, rack 4 moves to the right and then crosses the virtual threshold S at the end of its right stroke. D Therefore, rack 4 is located in the reduced auxiliary region ZAR on the right side. D It performs the entry motion. Then, the auxiliary motor M receives an equal amount of auxiliary motor C. assist Subtract the input resistance setpoint value C resistant Set point C setpoint In this way, rack 4 approaches the right-hand stop threshold P in a decelerated manner.D until it completely stops at the right-hand stop threshold P. D The movement in the direction of [the direction of travel]. That is, when the rack moves to the right, it crosses the virtual threshold S at the end of its right stroke. D Then stop its movement so that it never touches the right-hand stop threshold P. D touch.

[0123] Determine the input resistance setpoint value C resistant Such that when the stopping threshold P is located on the right side D When the mechanical stop engages, it gives the driver an accurate and intuitive feel for predictable behavior.

[0124] Rack 4 continues its leftward movement, thus completing its exit motion. Then, auxiliary motor M receives an auxiliary torque equal to C. assist Subtract the output resistance setpoint value C resistant Set point C setpoint .

[0125] Determine the output resistance setpoint value C resistant This allows the driver to have an accurate and intuitive feel for the predictable behavior of the rack after contacting the mechanical stop.

[0126] The entry viscosity coefficient b1 is strictly higher than the exit viscosity coefficient b2.

[0127] In this way, a high entry viscosity coefficient b1 allows for a reduction in the rack speed to prevent rack 4 from reaching the stop threshold at an excessive speed, and a low exit viscosity coefficient b2 allows for the avoidance of over-braking of the rack during exit motion.

[0128] Furthermore, the viscosity coefficient b1 was applied earlier than the stiffness coefficient k1.

[0129] Furthermore, when the stiffness coefficient k2 is removed from the application, the viscosity coefficient b2 is also removed.

[0130] By artificially hardening the movement of rack 4 and / or equivalently hardening the rotation of steering wheel 2, only from the virtual threshold S at the end of the stroke. G S D This can effectively protect the steering from impacts without hindering driving.

[0131] Of course, the present invention is not limited to the embodiments described and shown in the accompanying drawings. Modifications can still be made without departing from the scope of the invention, particularly regarding the construction of various elements or by substitution with technical equivalents.

Claims

1. A method for managing an auxiliary motor (M) of a power steering system (1) of a vehicle, the power steering system including an actuator member (4) that performs motion along a functional length (L0), the method comprising: - At least one reduction auxiliary region (ZAR) is defined on the functional length (L0) of the actuator component (4). D ZAR G The step of reducing the auxiliary region is achieved through a virtual threshold (S) at the end of the journey. G S D Separated from the normal auxiliary region (ZAN), - The step of evaluating the instantaneous position and direction of motion (D) of the actuator component (4) along the functional length (L0), - When the actuator component (4) moves from the normal auxiliary region (ZAN) to the reduced auxiliary region (ZAR) D ZAR G The method of crossing the virtual threshold of the trip end (S) G S D The step of applying the input resistance setpoint value to the auxiliary motor (M) at that time. The feature is that, after the step of applying the input resistance setpoint value, when the actuator component (4) is in the reduction assist region (ZAR) D ZAR G The actuator component (4) moves in a direction (D) from the reduced auxiliary region (ZAR). D ZAR G When pointing to the normal auxiliary region (ZAN), an output resistance setpoint value is applied, wherein the output resistance setpoint value includes: - The exit elastic component, which is related to the exit stiffness coefficient (k2) and the motion amplitude (X) of the actuator component (4). rack Proportional, and - Exit viscous component, which is related to the exit viscosity coefficient (b2) and the velocity of the actuator component (4). Proportional.

2. The method according to claim 1, wherein, The output resistance setpoint value also includes: - The exit inertial component, which is related to the exit inertial coefficient (m2) and the motion acceleration of the actuator component (4). Proportional.

3. The method according to any one of claims 1 and 2, wherein, The exit stiffness coefficient (k2) and / or exit viscosity coefficient (b2) and / or exit inertia coefficient (m2) depend on at least one of the following parameters: the displacement velocity of the vehicle equipped with the auxiliary motor (M), the torque (E) applied by the driver to the steering member (2). D The instantaneous position of the actuator component (4) and the amplitude of motion (X) of the actuator component (4) rack The speed of motion of the actuator component (4) The motion acceleration of the actuator component (4) ).

4. The method according to claim 1, wherein, The input resistance setpoint value includes: - The elastic component enters, which is related to the stiffness coefficient (k1) and the motion amplitude (X) of the actuator component (4). rack Proportional, and - Entering the viscous component, which is related to the entry viscosity coefficient (b1) and the velocity of the actuator component (4). Proportional.

5. The method according to claim 1, wherein, The input resistance setpoint value includes: - The elastic component enters, which is related to the stiffness coefficient (k1) and the motion amplitude (X) of the actuator component (4). rack Proportional, - Entering the viscous component, which is related to the entry viscosity coefficient (b1) and the velocity of the actuator component (4). Proportional, and - The inertial component, which is related to the inertial coefficient (m1) and the acceleration of motion of the actuator component (4). Proportional.

6. The method according to any one of claims 4 and 5, wherein, The entry stiffness coefficient (k1) and / or entry viscosity coefficient (b1) and / or entry inertia coefficient (m1) depend on at least one of the following parameters: the displacement velocity of the vehicle equipped with the auxiliary motor, the torque applied by the driver to the steering member, the instantaneous position of the actuator member, the motion amplitude of the actuator member, the motion velocity of the actuator member, and the motion acceleration of the actuator member.

7. The method according to claim 1, wherein, The at least one virtual threshold for the end of the journey depends on at least one of the following parameters: the displacement speed of the vehicle equipped with the auxiliary motor (M), the torque (E) applied by the driver to the steering member (2). D The instantaneous position of the actuator component and the amplitude of motion of the actuator component (4) (X) rack The speed of motion of the actuator component (4) The motion acceleration of the actuator component (4) ).

8. The method according to any one of claims 4 and 5, wherein, The entry viscosity coefficient (b1) has a higher value than the exit viscosity coefficient (b2).

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