METHOD FOR AUTOMATIC CONTROL OF THE ELECTRIC STEERING OF A MOTOR VEHICLE

Abstract

METHOD FOR AUTOMATIC CONTROL OF ELECTRIC STEERING OF A MOTOR VEHICLE The present invention relates to a method for controlling an exclusively electric steering system of a motor vehicle based on the position of a steering wheel of said motor vehicle, said control system being capable of producing force feedback to the steering wheel, notable in that said method comprises an automatic detection (102) of the vehicle's driving mode from among at least two driving modes (108, 112, 118), and an automatic adjustment of the level of force feedback to the steering wheel according to the detected driving mode. (Figure to be published with the abbreviation: Figure 2)

Description

Title of the invention: METHOD FOR AUTOMATICALLY CONTROLLING ELECTRIC STEERING OF A MOTOR VEHICLE Technical field

[0001] The present invention relates to the field of motor vehicles, more particularly the field of electrically controlled steering systems for motor vehicles. Prior art

[0002] Automobile manufacturers are offering more motor vehicles including electric driving functions, also referred to as: “drive-by-wire” driving functions, which may in particular include directional control functions: “steer-by-wire” provided by electric power steering units without a steering column, i.e. having no mechanical link between the steering wheel and the wheels.

[0003] Conventionally, in a conventional steering system provided with a mechanical link between the steering wheel and the wheels, said steering wheel transmits authentic feedback which reacts to real driving conditions and the state of the road.

[0004] In contrast, in the context of a vehicle equipped with a power steering system, the driver generally has difficulty perceiving feedback that is sufficiently immersive and representative of the environment in which the motor vehicle is moving.

[0005] Published patent document US 2014 / 0222296 A1 discloses a control system for a motor vehicle configured to act on the steering of said vehicle as a function of a relationship between a steering angle and a resulting yaw rate, so as to conform to the driver's preferences, in particular according to his preferred type of driving, i.e., driving in sport mode or in comfort mode.

[0006] However, the solution has room for improvement in order to provide the driver with a more immersive driving experience, and a more authentic steering sensation that is more faithful to the reality of the driving conditions, particularly in the case of a motor vehicle equipped with an exclusively electrically controlled steering system. Statement of the invention

[0007] The present invention aims to overcome at least one of the drawbacks of the aforementioned state of the art. More particularly, the invention aims to offer a simple, efficient and economical solution to provide a more immersive driving experience to the driver of a motor vehicle with an exclusively electrically controlled steering system.

[0008] To this end, the invention relates to a method for controlling an exclusively electric control system for steering wheels of a motor vehicle as a function of the position of a steering wheel of said motor vehicle, said control system being capable of producing force feedback to the steering wheel, remarkable in that said method comprises automatic detection of the driving mode of the motor vehicle from among at least two driving modes, and automatic adjustment of a level of force feedback to the steering wheel as a function of the detected driving mode.

[0009] According to one embodiment, the at least two driving modes comprise a city mode and a road mode faster than the city mode.

[0010] According to one embodiment, the at least two driving modes further comprise a parking mode, and where the detection of said parking mode is followed by an interaction with the driver inviting said driver to confirm his intention to carry out a parking maneuver.

[0011] According to one embodiment, the automatic detection of the driving mode is based on at least one of the parameters comprising an angular position of the steering wheel, a lateral acceleration of the motor vehicle, a lateral jerk of the motor vehicle and an instantaneous speed of the motor vehicle.

[0012] According to one embodiment, the detection of the road mode is established when the speed of the motor vehicle exceeds a limit value for a minimum duration.

[0013] According to one embodiment, the automatic adjustment of the force feedback level comprises a selection of a predefined force feedback level for each of the driving modes.

[0014] According to one embodiment, the level of force feedback predefined for each of the driving modes is manually adjustable by the driver.

[0015] The invention also relates to a motor vehicle comprising: - a steering wheel coupled to an electric actuator of said steering wheel; - steering wheels; - an electric device for controlling the angular position of the steered wheels; - a vehicle steering control unit, electrically connected to the electric actuator and the electrical control device; remarkable in that the control unit is configured to execute the method according to the invention.

[0016] According to one embodiment, the motor vehicle comprising a display offering a range of adjustment of the force feedback level between two limit values, for the corresponding driving mode.

[0017] The measures of the invention are advantageous in that the automatic adaptation of the level of force feedback to the steering wheel as a function of driving and the environment outside the motor vehicle makes it possible to offer the driver a personalized driving mode considerably improving the precision and quality of the feedback from the steering wheel, which makes the driving experience more comfortable.

[0018] In addition, the control method of the present invention makes it possible to improve road safety by offering the driver the possibility of adjusting the force feedback of the steering wheel according to the driving conditions, since this helps to reduce the risk of fatigue while driving, particularly during long journeys. Brief description of the drawings

[0019] [Fig.l] schematically represents an electrically controlled steering system of a motor vehicle according to the invention;

[0020] [Fig.2] illustrates a control flowchart of the steering system of the motor vehicle of [Fig.l], following a control method according to the invention. Detailed description

[0021] [Fig.l] schematically represents an exclusively electrically controlled steering system 4 of a motor vehicle 2 according to the invention.

[0022] This is an electric power steering system without mechanical connection between the steering wheel 6 and the right 8 and left 9 front steering wheels of the motor vehicle 2.

[0023] The steering 4 comprises an electric actuator for steering the steered wheels FWA of the motor vehicle 2, and an electric actuator for the steered steering wheel HWA, capable of being driven in rotation in a nominal angular range having two limit angular positions of the steering wheel 6.

[0024] The wheel actuator is commonly referred to as FWA, an acronym taken from the name English: "Front Wheel Actuator", and the steering wheel actuator is commonly referred to as HWA for: "Hand Wheel Actuator".

[0025] In this configuration, each of the wheel and steering wheel actuators may comprise a receiver (angular position sensor) and a transmitter (actuator), so as to actuate the front wheels 8, 9 by means of a rack 10 following receipt of an angular position of the steering wheel, and vice versa.

[0026] Preferably, the electric steering system 4 is controlled by a control unit 12 of the motor vehicle 2, directly connected to each of the actuators FWA and HWA, respectively by means of an input 12.1 for a signal representative of the angular position of the steering wheel 6, and an output 12.2 for a signal controlling the steered wheels 8, 9.

[0027] The control unit 12 further comprises a control signal output to the steering wheel 6 and a signal input representative of the angular position of the steering wheels 8, 9.

[0028] The steering wheel 6 may comprise physical or virtual stops. Preferably, the HWA actuator of the steering wheel 6 is configured to generate maximum force feedback at the two limit angular positions of the steering wheel 6, so as to form two virtual end-of-travel stops of the steering wheel.

[0029] Advantageously, the steering wheel 6 is capable, thanks to the HWA actuator, of providing force feedback which can vary between the two limit angular positions. The present invention proposes a method for controlling the electric steering system 4 by means of the control unit 12. The different steps of said method will be detailed below.

[0030] [Fig.2] illustrates a logic diagram 100 for controlling the steering system 4 of the motor vehicle 2 of [Fig.1], using the control method according to the invention.

[0031] Advantageously, the method of the invention makes it possible to ensure a correlation between the real driving conditions and the force feedback to the steering wheel felt by the driver, in order to automatically adjust a level of said force feedback as a function of the driving mode detected, so as to obtain a more immersive driving style that is more connected to the environment external to the motor vehicle.

[0032] In this regard, the method of the invention comprises a first step of automatic detection of driving mode 102 of the motor vehicle from among at least two driving modes, and preferably from among three driving modes, comprising: a parking mode 118, a city mode 112 and a road mode 108 faster than the city mode 112.

[0033] At step 104 of the flowchart, the control unit evaluates whether the driving speed of the motor vehicle is less than 50 km / h, if this is not the case, then the road mode 108 is selected, and the actuator of the steering wheel HWA of [Fig.l] adapts the force feedback level to the road mode at step 110.

[0034] Preferably, the adjustment of the force feedback level in step 110 comprises the selection of a predefined force feedback level recorded by the control unit, said level preferably being higher than that applied in city mode, so as to limit unwanted or intentional movements of the steering wheel when driving at high speed, on a motorway for example, thus improving road safety.

[0035] Adjusting the force feedback level may comprise adapting a torque value setpoint in Nm dictated to the HWA actuator. Alternatively, the force feedback level depends on a linear or non-linear law between the directional torque exerted by the wheels on the mechanical steering control system and the torque exerted on the steering wheel by the HWA actuator.

[0036] In step 106, a verification of the driving conditions is carried out, this is an automatic detection of the driving mode based on at least one of the parameters comprising the angular position of the steering wheel, the instantaneous or average speed of the motor vehicle, a lateral acceleration of the motor vehicle and / or a lateral jerk of the motor vehicle, also referred to as “lateral jerk”, the latter being measured in meters per cubic second.

[0037] Depending on the results of the measurements in step 106, the control unit determines the selection choice between the road mode 108 and the city mode 112. For example, if the speed of the motor vehicle exceeds a (predetermined) limit value for a minimum duration, then the detection of the road mode 108 can be established. Otherwise, the city mode 112 is directly selected, and the HWA actuator adjusts the force feedback level in step 116, so as to allow easy maneuverability of the motor vehicle, in particular for making turns with little effort.

[0038] Then, the control unit checks in step 114 whether a parking maneuver takes place while driving in city mode. In this respect, measurements substantially similar to those carried out in step 106 are carried out. For example, when the speed of the vehicle is below a threshold, preferably equal to 15 km / h, and more preferably, when a possible on-board camera system of the vehicle distinguishes a parking maneuver, then the parking mode 118 is selected.

[0039] Preferably, the detection of said parking mode 118 is followed by an interaction with the driver inviting him to confirm his intention to carry out a parking maneuver, this in particular makes it possible to avoid confusion with slow driving in town (at a speed lower than 15 km / h). This invitation can, for example, be presented in the form of a question to the driver, such as: “Are you looking for a parking space?”, by means of a display in the passenger compartment which may correspond to the “cockpit” of the dashboard and / or an infotainment screen. If the driver accepts or answers “yes” to the question, then the HWA actuator will adapt the force feedback level of the steering wheel in step 122 to further minimize it and thus make it possible to facilitate the steering operations during the parking maneuver.

[0040] Preferably, the display in the passenger compartment also offers, for each of the three driving modes 108, 112 and 118, the possibility of adjusting the predefined force feedback level. In such a configuration, the display can have a range of values, such as a scale from 1 to 10, and making it possible to adjust and save the new force feedback intensity associated with the corresponding driving mode, said new intensity will be automatically applied subsequently in the event of detection.

[0041] The present invention is not limited solely to the three driving modes. mentioned above. Indeed, the automatic adaptation of the force feedback level can also depend on the traffic density and / or the condition of the road, and / or the type of road, i.e., winding, fast lane, etc.

Claims

Claims

1. Method for controlling an exclusively electric steering control system (4) for the wheels of a motor vehicle (2) as a function of the position of a steering wheel (6) of said motor vehicle (2), said control system (4) being capable of producing force feedback to the steering wheel (6), characterized in that said method comprises automatic detection of the driving mode (102) of the motor vehicle (2) among at least two driving modes (108, 112, 118), and automatic adjustment of a level of force feedback to the steering wheel (6) as a function of the driving mode (108, 112, 118) detected.

2. The method of claim 1, wherein the at least two driving modes (108, 112, 118) comprise a city mode (112) and a highway mode (108) faster than the city mode (112).

3. Method according to claim 2, wherein the at least two driving modes (108, 112, 118) further comprise a parking mode (118), and wherein the detection of said parking mode (118) is followed by an interaction with the driver inviting said driver to confirm his intention to carry out a parking maneuver.

4. Method according to one of claims 1 to 3, in which the automatic detection of the driving mode (108, 112, 118) is based on at least one of the parameters comprising an angular position of the steering wheel (6), a lateral acceleration of the motor vehicle (2), a lateral jerk of the motor vehicle (2) and an instantaneous speed of the motor vehicle (2).

5. Method according to one of claims 2 and 3, and according to claim 4, in which the detection of the road mode (108) is established when the speed of the motor vehicle (2) exceeds a limit value for a minimum duration.

6. A method according to one of claims 1 to 5, wherein the automatic adjustment of the force feedback level comprises a selection of a predefined force feedback level for each of the driving modes (108, 112, 118).

7. The method of claim 6, wherein the predefined force feedback level for each of the driving modes (108, 112, 118) is manually adjustable by the driver.

8. Motor vehicle (2) comprising: - a steering wheel (6) coupled to an electric actuator (HWA) of said steering wheel (6); - steered wheels (8, 9); - an electrical device (FWA) for controlling the angular position of the steered wheels (8, 9); - a control unit (12) for steering the vehicle (2), electrically connected to the electric actuator (HWA) and to the electrical control device (FWA); characterized in that the control unit (12) is configured to execute the method according to one of claims 1 to 7.

9. Motor vehicle (2) according to claim 8, comprising a display offering a range of adjustment of the force feedback level between two limit values, for the corresponding driving mode (108, 112, 118).

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