MONITORING A POWER STEERING DEVICE OF A LAND VEHICLE TO DETECT ABNORMAL WHEEL INSTABILITY

Abstract

A monitoring method is implemented in a land vehicle comprising wheels coupled to a power steering device associated with a steering wheel. This method comprises a step (10-30) in which a first frequency of variation of an angle of rotation of the steering wheel is compared to a first chosen threshold and / or a second frequency of variation of a torque to a second chosen threshold, and, when this first frequency of variation is greater than the first threshold and / or this second frequency of variation is greater than the second threshold, an alert message is generated requiring a check of the wheels, intended for the driver of the vehicle. Figure 3

Description

Title of the invention: MONITORING OF A POWER STEERING DEVICE OF A LAND VEHICLE TO DETECT ABNORMAL INSTABILITY OF THE WHEELS Technical field of the invention

[0001] The invention relates to wheeled land vehicles, and more specifically to monitoring the stability of the wheels within such vehicles. State of the art

[0002] Certain land vehicles, possibly of the automobile type, comprise wheels which are coupled to a power steering device, possibly electric and associated with a steering wheel which can be rotated by their driver.

[0003] The steered wheels of land vehicles have hubs which are usually secured, by screwing (or bolting), to a spindle bowl carried by a pivot to which is coupled in rotation (in particular) a steering rack coupled to the power steering device. Consequently, when the screwing (or bolting) is no longer correct or when a rotational coupling is no longer correct, a steered wheel may be subject to instability which affects the comfort and precision of road holding, which is potentially dangerous or may become potentially dangerous in the event of aggravation.

[0004] However, there is currently no known solution for detecting wheel instability, and therefore the driver of the vehicle concerned cannot be warned even though it may become, or is, potentially dangerous.

[0005] The invention therefore aims in particular to improve the situation. Presentation of the invention

[0006] For this purpose, it proposes in particular a monitoring method intended to be implemented in a land vehicle comprising wheels coupled to a power steering device associated with a steering wheel.

[0007] This monitoring method is characterized by the fact that it comprises a step in which a first frequency of variation of an angle of rotation of the steering wheel is compared to a first chosen threshold and / or a second frequency of variation of a torque, applied by the steering wheel to the power steering device, to a second chosen threshold, and when this first frequency of variation is greater than this first threshold and / or this second frequency of variation is greater than this second threshold, an alert message is generated requiring a check of the wheels, intended for a driver of the vehicle.

[0008] Thus, it is now possible to detect, simply and without adding a dedicated sensor, an in stability at the level of at least one steering wheel, and alert the driver of the vehicle to have it checked quickly by an after-sales service.

[0009] The monitoring method according to the invention may include other characteristics which may be taken separately or in combination, and in particular:

[0010] - in its step, a visual alert message and / or a message can be generated audible alert;

[0011] - in its step, the first threshold can be fixed, and the second threshold can be fixed;

[0012] - alternatively, in its step, each of the first and second thresholds may be a function of at least one variable which is chosen from a state of a traffic lane on which the vehicle is traveling and a current speed of the vehicle.

[0013] The invention also provides a computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing a monitoring method of the type presented above, in a land vehicle comprising wheels coupled to a power steering device associated with a steering wheel, to detect abnormal instability of the wheels.

[0014] The invention also proposes a monitoring device intended to equip a land vehicle comprising wheels coupled to a power steering device associated with a steering wheel, to detect abnormal instability of the wheels.

[0015] This monitoring device is characterized by the fact that it comprises at least one processor and at least one memory arranged to carry out the operations consisting of comparing a first frequency of variation of an angle of rotation of the steering wheel with a first chosen threshold and / or a second frequency of variation of a torque, applied by the steering wheel to the power steering device, with a second chosen threshold, and when this first frequency of variation is greater than this first threshold and / or this second frequency of variation is greater than this second threshold, to trigger a generation of an alert message requiring a check of the wheels, intended for a driver of the vehicle.

[0016] The invention also proposes a land vehicle, possibly of the automobile type, and comprising, on the one hand, wheels coupled to a power steering device associated with a steering wheel, and, on the other hand, a monitoring device of the type presented above.

[0017] For example, the power steering device may be electric. In this case, the power steering device may comprise a computer comprising the monitoring device. Brief description of the figures

[0018] Other characteristics and advantages of the invention will appear on examining the detailed description below, and the appended drawings, in which:

[0019] [Fig.l] schematically and functionally illustrates an exemplary embodiment of a land vehicle comprising wheels, a GMP transmission chain with an electric motor, a power steering device comprising a steering computer, and a monitoring device according to the invention,

[0020] [Fig.2] schematically and functionally illustrates an example of the embodiment of a steering calculator comprising an exemplary embodiment of a monitoring device according to the invention, and

[0021] [Fig.3] schematically illustrates an example of an algorithm implementing a monitoring method according to the invention. Detailed description of the invention

[0022] The invention aims in particular to propose a monitoring method, and an associated monitoring device DS, intended to enable monitoring, in a land vehicle V, of a power steering device DDA controlling the direction of steered wheels RV, to detect abnormal instability of at least one of these wheels RV.

[0023] In the following, it is considered, by way of non-limiting example, that the land vehicle V is of the automobile type. It is for example a car, as illustrated in [Fig.l]. But the invention is not limited to this type of land vehicle. It in fact relates to any type of land vehicle comprising steered wheels whose orientation is controlled by a power steering device. Thus, it relates to utility vehicles, camper vans, minibuses, coaches, trucks, motorcycles, road machinery, construction machinery and agricultural machinery, for example.

[0024] Furthermore, it is considered in the following, by way of non-limiting example, that the land vehicle V comprises a transmission chain with a powertrain (or GMP) of the all-electric type (and therefore whose drive is provided exclusively by at least one electric motor MME). But the GMP could be of the hybrid type (thermal and electric) or purely thermal.

[0025] [Fig.l] schematically shows a (land) vehicle V comprising wheels RV, a transmission chain with electric GMP (and therefore with electric motor MME), a power steering device DDA comprising a steering computer CD, and a monitoring device DS according to the invention.

[0026] The transmission chain has a GMP which is, here, purely electric and therefore which comprises, in particular, an electric motor MME, a motor shaft, and a transmission shaft. Here, the term “electric motor” means an electric machine arranged so as to provide engine torque to move the vehicle V when it is supplied with electrical energy, as well as possibly to recover torque in the drive chain.

[0027] The electric motor MME (here an electric motor) is supplied with electrical energy by a main battery (not shown), rechargeable and possibly cellular. Furthermore, this electric motor MME is coupled to the motor shaft, to provide it with motor torque by rotational drive, and this motor shaft is here coupled to a reducer RD which is also coupled to the transmission shaft, itself coupled to a first train T1, preferably via a differential DF.

[0028] This first train T1 is here located in the front part PVV of the vehicle V. Consequently, in this example the RV wheels of the first train T1 are both driving and steering. But in a variant this first train T1 could be the one which is here referenced T2 and which is located in the rear part PRV of the vehicle V, and in this case the (front) wheels RV are only steering (the rear wheels of the second rear train T2 then being, a priori, only driving).

[0029] The power steering device DDA is associated with the steering wheel VV which allows the driver of the vehicle V to control the direction of the steered wheels RV of the first axle T1 (front). For this purpose, it comprises a mechanical part PM connected to the steering wheel VV. This power steering device DDA is also coupled to a steering rack CRD which is coupled to the steered wheels RV and responsible for orienting the latter (RV) according to the action of the driver on the steering wheel VV.

[0030] It will be noted that in the example illustrated non-limitingly in [Fig.l] the power steering device DDA is electric, and therefore its mechanical part PM is not connected to the steering rack CRD. In this case, the latter (CRD) is controlled according to instructions which are determined, according to the action of the driver on the steering wheel VV, by a steering computer CD forming part of the power steering device DDA. But in a variant not illustrated the power steering device DDA could be conventional (i.e. non-electric), and in this case its mechanical part is connected to the steering rack CRD.

[0031] As mentioned above, the invention proposes in particular a monitoring method intended to enable monitoring of the power steering device DDA to detect abnormal instability of at least one (steering) wheel RV.

[0032] This (monitoring) method can be implemented at least partially by the monitoring device DS (illustrated at least partially in FIGS. 1 and 2) which comprises for this purpose at least one processor PR1, for example a digital signal processor (or DSP ("Digital Signal Processor")), and at least one memory MD. This monitoring device DS can therefore be produced in the form of a combination of electrical or electronic circuits or components (or "hardware") and software modules (or "software"). For example, it can be a microcontroller.

[0033] The memory MD is live in order to store instructions for the implementation by the processor PR1 of at least part of the monitoring method. The processor PR1 may comprise integrated (or printed) circuits, or several integrated (or printed) circuits connected by wired or wireless connections. An integrated (or printed) circuit is understood to mean any type of device capable of carrying out at least one electrical or electronic operation.

[0034] In the example illustrated non-limitingly in Figures 1 and 2, the monitoring device DS is part of the steering computer CD. But this is not obligatory. Indeed, the monitoring device DS could comprise its own dedicated computer, which is then coupled to the steering computer CD, for example.

[0035] As illustrated non-limitingly in [Fig. 3], the (monitoring) method, according to the invention, comprises a step 10-30 which is implemented each time the vehicle V moves, and therefore its GMP provides it with engine torque.

[0036] Step 10-30 of the method comprises a sub-step 20 in which one (for example the monitoring device DS) compares a first variation frequency fvl of the rotation angle of the steering wheel VV to a first threshold if chosen and / or a second variation frequency fv2 of a torque, applied by the steering wheel VV to the power steering device DDA (and more precisely to its mechanical part PM), to a second threshold s2 chosen.

[0037] It will be understood that three different embodiments can be envisaged. In a first embodiment, one (for example the monitoring device DS) only compares the first variation frequency fvl to the first threshold s1. In a second embodiment, one (for example the monitoring device DS) only compares the second variation frequency fv2 to the second threshold s2. In a third embodiment, one (for example the monitoring device DS) compares not only the first variation frequency fvl to the first threshold s1, but also the second variation frequency fv2 to the second threshold s2.

[0038] The first variation frequency fvl can be deduced from the successive rotation angles of the steering wheel VV in a chosen time interval (and for example sliding). This rotation angle is permanently known to the steering computer CD thanks to the presence of a dedicated sensor equipping its mechanical part PM.

[0039] The second variation frequency fv2 can be deduced from the successive torques applied by the steering wheel VV to the mechanical part PM of the power steering device DDA in a chosen time interval (and for example sliding). This torque is permanently known to the steering computer CD thanks to the presence of another dedicated sensor equipping its mechanical part PM.

[0040] For example, and as illustrated non-limitingly in [Fig.3], step 10-30 may comprise a sub-step 10 in which the monitoring device DS may de terminate the first variation frequency fvl and / or the second variation frequency fv2, depending on the embodiment implemented.

[0041] Step 10-30 of the method also comprises a sub-step 30 in which, when the first variation frequency fvl is greater than the first threshold s1 and / or the second variation frequency fv2 is greater than the second threshold s2, an alert message is generated (for example the monitoring device DS triggers the generation of an alert message requiring a check of the wheels RV, intended for the driver of the vehicle V.

[0042] It will be understood that in the first embodiment mentioned above, it is when the first variation frequency fvl is greater than the first threshold s1 that an alert message is generated (for example, the monitoring device DS triggers the generation of an alert message). In the second embodiment mentioned above, it is when the second variation frequency fv2 is greater than the second threshold s2 that an alert message is generated (for example, the monitoring device DS triggers the generation of an alert message). In the third embodiment mentioned above, it is when the first variation frequency fvl is greater than the first threshold s1 and / or the second variation frequency fv2 is greater than the second threshold s2 that an alert message is generated (for example, the monitoring device DS triggers the generation of an alert message).

[0043] The first variation frequency fvl, just like the second variation frequency fv2, is in fact characteristic, with a high probability, of an instability at the level of at least one steered wheel RV, resulting from an unscrewing of a hub or from poor parallelism or balancing, and which results in vibrations at the level of the mechanical part PM of the power steering device DDA which induce variations in the angle of rotation of the steering wheel VV and / or the steering wheel torque. In the third embodiment mentioned above, the use of two conditions (with at least one having to be satisfied) makes it possible to increase the probability of detecting an instability. It will be noted that in the third embodiment mentioned above, when it is required that the two conditions be simultaneously satisfied, the probability of detecting a false instability is very significantly reduced.

[0044] Thanks to the invention, it is now possible to detect, simply and without adding a dedicated sensor, instability at the level of at least one steered wheel RV, in order to alert the driver of the vehicle V, so that he can quickly have the latter (V), and more precisely its steered wheels RV, checked in an after-sales service.

[0045] It will be noted, as illustrated non-limitingly in [Fig. 3], that in sub-step 20, when the first variation frequency fvl is less than or equal to the first threshold s 1 and / or the second variation frequency fv2 is less than or equal to the second threshold s2, one (for example the monitoring device DS) performs sub-step 10 again with the following values ​​of the first variation frequency fvl and / or of the second variation frequency fv2.

[0046] For example, in sub-step 30 of step 10-30 it is possible to generate (for example the monitoring device DS can trigger the generation) a visual alert message and / or an audible alert message.

[0047] The visual alert message may be provided, for example, by means of an illuminated indicator light (for example in the dashboard of the vehicle V) and / or a message displayed on at least one screen of the vehicle V (for example on the dashboard or a central instrument panel) or on the screen of a driver's smartphone. The aforementioned indicator light may, for example, be a service indicator light, but it could also be a indicator light dedicated to wheel instability.

[0048] The audible alert message may be broadcast, for example, by at least one loudspeaker of the vehicle V or of the aforementioned smartphone.

[0049] Also for example, in sub-step 20 of step 10-30 the first threshold si can be fixed (and therefore predefined) and the second threshold s2 can be fixed (and therefore predefined). In this case, the first si and second s2 thresholds can be determined in a test phase of a vehicle similar to the vehicle V, then are stored in a memory of the monitoring device DS or the steering computer CD.

[0050] Alternatively, in sub-step 20 of step 10-30 each of the first si and second s2 thresholds may be a function of at least one variable which is chosen from the state of the traffic lane on which the vehicle V is traveling and the current speed of the vehicle V. It will be understood that the more defects the traffic lane has, the more these defects will amplify the vibrations induced by instability of the wheel(s). Similarly, the higher the current speed of the vehicle V, the more this will amplify the vibrations induced by instability of the wheel(s).

[0051] In this alternative embodiment, the monitoring device DS may be arranged so as to determine in sub-step 20 the first si and second s2 thresholds as a function of each chosen variable, before carrying out the (each) comparison. For this purpose, the monitoring device DS may, for example, use mathematical formulas or correspondence tables (or maps), for example determined during a test phase of a vehicle similar to the vehicle V.

[0052] It will also be noted, as illustrated non-limitingly in [Fig. 2], that the steering computer CD (or the computer of the monitoring device DS) can also comprise a mass memory MM1, in particular for storing the angles of rotation of the steering wheel VV and / or the steering wheel torques and any state(s) of the traffic lane and / or current speed of the vehicle V, as well as any intermediate data involved in all its calculations and processing. Furthermore, this steering computer CD (or the computer of the monitoring device DS) can also comprise an input interface IE for receiving at least the angles of rotation of the steering wheel VV and / or the steering wheel torques and any state(s) of the traffic lane and / or current speed of the vehicle V to use them in calculations or processing, possibly after having formatted and / or demodulated and / or amplified them, in a manner known per se, by means of a digital signal processor PR2. In addition, this steering computer CD (or the computer of the monitoring device DS) may also include an output interface IS, in particular to deliver a message (or order) for generating an alert message.

[0053] It will also be noted that the invention also proposes a computer program product (or computer program) comprising a set of instructions which, when executed by processing means of the electronic circuit (or hardware) type, such as for example the processor PR1, is capable of implementing the monitoring method described above to monitor in the vehicle V its power steering device DD A in order to detect abnormal instability of at least one (steering) wheel RV.

Claims

Claims

1. Monitoring method for a land vehicle (V) comprising wheels (RV) coupled to a power steering device (DDA) associated with a steering wheel (VV), characterized in that it comprises a step (10-30) in which a first frequency of variation of an angle of rotation of said steering wheel (VV) is compared to a first chosen threshold and / or a second frequency of variation of a torque, applied by said steering wheel (VV) to said power steering device (DDA), to a second chosen threshold, and when said first frequency of variation is greater than said first threshold and / or said second frequency of variation is greater than said second threshold, an alert message is generated requiring a check of said wheels (RV), intended for a driver of said vehicle (V).

2. Method according to claim 1, characterized in that in said step (10-30) a visual alert message and / or an audible alert message is generated.

3. A method according to claim 1 or 2, characterized in that in said step (10-30) said first threshold is fixed, and said second threshold is fixed.

4. Method according to claim 1 or 2, characterized in that in said step (10-30) each of said first and second thresholds is a function of at least one variable chosen from a state of a traffic lane on which said vehicle (V) is traveling and a current speed of said vehicle (V).

5. Computer program product comprising a set of instructions which, when executed by processing means, is capable of implementing the monitoring method according to one of claims 1 to 4, in a land vehicle (V) comprising wheels (RV) coupled to a power steering device (DDA) associated with a steering wheel (VV), to detect abnormal instability of said wheels (RV).

6. Monitoring device (DS) for a land vehicle (V) comprising wheels (RV) coupled to a power steering device (DDA) associated with a steering wheel (VV), characterized in that it comprises at least one processor (PR1) and at least one memory (MD) arranged to carry out the operations consisting of comparing a first frequency of variation of an angle of rotation of said steering wheel (VV) with a first chosen threshold and / or a second frequency of variation of a torque, applied by said steering wheel (VV) to said steering device

7.

8.

9.

10. assisted (DDA), at a second chosen threshold, and when said first variation frequency is greater than said first threshold and / or said second variation frequency is greater than said second threshold, to trigger generation of an alert message requiring a check of said wheels (RV), intended for a driver of said vehicle (V). Land vehicle (V) comprising wheels (RV) coupled to a power steering device (DDA) associated with a steering wheel (VV), characterized in that it further comprises a monitoring device (DS) according to claim 6. Land vehicle according to claim 7, characterized in that said power steering device (DDA) is electric. Land vehicle according to claim 8, characterized in that said power steering device (DDA) comprises a computer (CD) comprising said monitoring device (DS). Land vehicle according to one of claims 7 to 9, characterized in that it is of the automobile type.

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