ADAPTIVE METHOD FOR PREVENTIVE MAINTENANCE OF A VEHICLE

Abstract

The invention relates to an adaptive method for the preventive maintenance of a vehicle comprising a part with a plurality of sensors, the method comprising the following steps: - a measurement step (E11) of a plurality of parameters during an observation period by the plurality of sensors; - a calculation step (E12) of a damage estimation value for the part from the plurality of parameters measured during the observation period; - a calculation step (E13) of a failure probability value for the part from the calculated damage estimation value; - a signaling step (E14) of the part when the calculated failure probability value exceeds a predetermined probability threshold value in order to perform preventive maintenance on the vehicle. Figure 1

Description

Title of the invention: ADAPTIVE METHOD FOR PREVENTIVE MAINTENANCE OF A VEHICLE

[0001] The present invention relates to vehicles in the automotive field, and more particularly to preventive maintenance methods for motor vehicles.

[0002] Patent application CN117976098 describes a method comprising a step of measuring a plurality of parameters of a vehicle part by a plurality of sensors, a step of calculating a first plurality of values ​​by simulation, a step of calculating a second plurality of values ​​from the plurality of measured parameters, a step of calculating mechanical fatigue damage from the first plurality of values ​​and the second plurality of values.

[0003] However, such a process is limited to calculating the damage to the part without anticipating possible failures, in particular by evaluating and re-evaluating the risk of failure of the part based on the calculated damage.

[0004] The invention proposes to remedy this drawback by proposing a simple method ensuring preventive vehicle maintenance.

[0005] To achieve this objective, the invention proposes an adaptive method for preventive maintenance of a vehicle comprising a part including a plurality of sensors, the method comprising the following steps: - a step of measuring a plurality of parameters during an observation period by the plurality of sensors; - a step of calculating an estimated damage value for the part from the plurality of parameters measured during the observation period; - a step of calculating a probability value of failure of the part from the calculated damage estimate value; - a step to report the part when the calculated probability of failure value is greater than a predetermined probability threshold value in order to carry out preventive maintenance on the vehicle.

[0006] The invention makes it possible, in particular, to compare the calculated damage of the part with the calculated damage of other parts, for example, in terms of the severity of mechanical stress. Furthermore, the method makes it possible to compare the condition of the part with a condition predetermined by testing, so that the probability of failure can be accurately estimated for the part. Moreover, the estimated failure value is integrated into subsequent calculations of the estimated failure value, so that the subsequent calculations of the estimated failure value... be more precise and reliable, facilitating the anticipation and planning of preventive maintenance actions.

[0007] Advantageously, the part is a power converter.

[0008] Advantageously, the part is a rotor or a stator.

[0009] Advantageously, the part is a reducer.

[0010] Advantageously, the plurality of sensors includes an angular velocity sensor configured to measure an angular velocity value, the plurality of parameters including the angular velocity value.

[0011] Advantageously, the plurality of sensors includes a torque sensor configured to measure a torque value, the plurality of parameters including the torque value.

[0012] Advantageously, the plurality of sensors includes a temperature probe configured to measure a temperature value, the plurality of parameters including the temperature value.

[0013] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig. 1] illustrates a flowchart representing the steps of an adaptive process preventive maintenance of a vehicle power converter according to a first embodiment of the invention; - [Fig.2] illustrates a flowchart representing the steps of the adaptive process preventive maintenance of a rotor or stator of a vehicle according to a second embodiment of the invention; - [Fig.3] illustrates a flowchart representing the steps of the adaptive process preventive maintenance of a vehicle reducer according to a third embodiment of the invention.

[0014] A flowchart of an adaptive preventive maintenance process for a vehicle is illustrated in [Fig.1], according to a first embodiment, with steps of the process being described below.

[0015] According to the first embodiment, the vehicle comprises a part, the part being a power converter. The part comprises a plurality of sensors.

[0016] In an Eli measurement step, a plurality of parameters is measured during an observation period by the plurality of sensors.

[0017] The plurality of sensors includes a temperature probe configured to measure a temperature value.

[0018] The plurality of parameters includes a temperature value measured during the observation period by the temperature probe.

[0019] The observation period is preferably less than or equal to 7 years, or even 15 years, or to a duration of use corresponding to a distance travelled by the vehicle, for example equal to 150,000 km.

[0020] The process advantageously includes a calculation step E' 11 of an acceleration coefficient, denoted AF, calculated by the following formula - similar to an Arrhenius law: Ap = exp^ - T" ) j where £« is a predetermined activation energy value, for example, equal to 0.7 eV, Kb is a value of the Boltzmann constant, for example, equal to g. i(p8eV / K, T j is a temperature value predetermined by tests of the high temperature operation endurance type, also called HTOE for "high temperature operation endurance", or of the power thermal cycle endurance type, also called PTCE for "power thermal cycle endurance", or more broadly tests exposing the part to high temperature, for example above 50°C, T2 is a temperature value measured by the temperature probe.

[0021] The calculated acceleration coefficient is preferably less than or equal to 10.

[0022] In a calculation step El2, an estimated damage value for the part, denoted E, is calculated using the following formula: / 7 _ 2Lwhere AF is the calculated acceleration coefficient, E' is a predetermined damage estimate value obtained through thermomechanical tests, for example, thermal fatigue tests.

[0023] The method advantageously includes a first case of calculating a distribution function or a second case of calculating the distribution function.

[0024] In the first calculation case, the process advantageously includes a step of calculating a distribution function, denoted F, calculated by the following formula: , where E is the estimated damage value FK(E) predetermined by testing, x is a damage value, / „ is a function predetermined by trials, for example validation trials, / ■ / 1 being a probability value that the part will fail before reaching the damage value x.

[0025] Alternatively, in the second calculation case, the method advantageously includes a step of calculating a distribution function, denoted FR, calculated by the following formula: " ", where E is the estimated damage value predetermined by trials, x' is a damage value, fR is a function determined by a maximum likelihood method based on the calculated damage estimate value, or, more broadly, on several calculated damage estimate values.

[0026] In a calculation step E13, a probability value of failure of the part is calculated from the calculated damage estimate value.

[0027] The method includes a first case of calculating the probability of failure value or a second case of calculating the probability of failure value.

[0028] In the first calculation case, the method advantageously includes a step of calculating the probability value of failure of the part, denoted Pf, calculated by the following formula:

[0029]

[0030]

[0031] n / ^ .^°ù E is a damage value, " / -Jq J fc is a function of the use of the determined part, p being a value the probability that the part will suffer damage E during the observation period, FR is the calculated part resistance distribution function. In practice, the first calculation case applies when a first estimated value of damage to the part is calculated. Alternatively, in the second calculation case, the process advantageously includes a step of calculating the probability value of failure of the part, the probability value of failure of the part, denoted P f, being calculated by the following formula: n, y-, xr^where E is a damage value, fc is a function of the use of the determined part, f being a value the probability that the part will suffer damage E during the observation period, Fr is the part strength distribution function calculated by the maximum likelihood type method on the basis of the calculated damage estimate value, or, more broadly, several calculated damage estimate values. In an El4 reporting step, the part is reported when the calculated probability of failure value is greater than a predetermined probability threshold value in order to perform preventive maintenance on the vehicle.

[0032] For example, the calculated probability of failure value is compared to a predetermined probability threshold value, denoted by the following formula: pj. > p* For example, the predetermined probability threshold value is equal to 1000 parts per million.

[0033] This makes it possible to determine whether a part should be replaced when the calculated probability of failure value is greater than the predetermined probability threshold value.

[0034] A flowchart of an adaptive preventive maintenance process for a vehicle is illustrated in [Fig.2], according to a second embodiment, steps of the process being described below.

[0035] According to the second embodiment, the vehicle comprises a part, the part being a rotor or a stator. The part comprises a plurality of sensors.

[0036] In a measurement step E21, a plurality of parameters is measured during an observation period by the plurality of sensors.

[0037] The plurality of sensors includes a temperature probe configured to measure a temperature value.

[0038] The plurality of parameters includes a first temperature value measured during the observation period and a second temperature value measured during the observation period.

[0039] The process advantageously includes a calculation step E'21 of an acceleration coefficient, denoted AF, calculated by the following formula - similar to a Coffin-Manson law: / T,-Tt V^where M is a coefficient depending on the material of the part, af = \ÂT7 / Tj is the first measured temperature value, T2 is the second measured temperature value, ATV is a temperature differential value predetermined by testing.

[0040] In a calculation step E22, a damage estimate value for the part, denoted E, is calculated using the following formula: j? _ 22. where Af is the calculated acceleration coefficient, Af E' is a predetermined damage estimate value obtained through thermomechanical tests, for example, thermal fatigue tests.

[0041] In a calculation step E23, a probability value of failure of the part is calculated from the calculated damage estimate value.

[0042] In an E24 reporting step, the part is reported when the calculated probability of failure value is greater than a predetermined probability threshold value so as to carry out preventive maintenance of the vehicle.

[0043] A flowchart of an adaptive preventive maintenance process for a vehicle is illustrated in [Fig.3], according to a third embodiment, steps of the process being described below.

[0044] According to the third embodiment, the vehicle comprises a part, the part being a reducer. The part comprises a plurality of sensors.

[0045] In a measurement step E31, a plurality of parameters is measured during an observation period by the plurality of sensors.

[0046] The plurality of sensors includes an angular velocity sensor configured to measure an angular velocity value, for example an inductive sensor, a Hall effect sensor, or an optical angular velocity sensor.

[0047] The plurality of sensors also includes a torque sensor configured to measure a torque value, for example a strain gauge torque meter, a dynamic torque sensor, or a magnetic effect torque meter.

[0048] The plurality of parameters includes an angular velocity value measured by the angular velocity sensor and a torque value measured by the torque sensor.

[0049] In a calculation step E32, an estimated damage value for the part, denoted E, is calculated using the following formula: E-{ NC)*°where N is a number of rotations calculated from the measured rotational speed value, C is the measured torque value, k is a parameter dependent on the failure mode of the reducer, the parameter being for example equal to 3, 5, or even 7, E is a predetermined damage estimate value determined by tests.

[0050] In a calculation step E33, a probability value of failure of the part is calculated from the calculated damage estimate value.

[0051] In an E34 reporting step, the part is reported when the calculated probability of failure value is greater than a vehicle probability threshold value.

Claims

Demands

1. An adaptive method for preventive maintenance of a vehicle comprising a part including a plurality of sensors, the method comprising the following steps: - a measurement step (E1, E21, E31, E41) of a plurality of parameters during an observation period by the plurality of sensors; - a calculation step (E12, E22, E32, E42) of a damage estimation value of the part from the plurality of parameters measured during the observation period; - a calculation step (E13, E23, E33, E43) of a failure probability value of the part from the calculated damage estimation value; - a signaling step (E14, E24, E34, E44) of the part when the calculated failure probability value is greater than a predetermined probability threshold value so as to perform preventive maintenance on the vehicle.

2. Method according to claim 1, characterized in that the part is a power converter.

3. Method according to claim 1, characterized in that the part is a rotor or a stator.

4. Method according to claim 1, characterized in that the part is a reducer.

5. A method according to claim 3 or 4, characterized in that the plurality of sensors comprises an angular velocity sensor configured to measure an angular velocity value, the plurality of parameters comprising the angular velocity value.

6. A method according to claim 3 or 4, characterized in that the plurality of sensors comprises a torque sensor configured to measure a torque value, the plurality of parameters comprising the torque value.

7. A method according to any one of claims 1 to 6, characterized in that the plurality of sensors comprises a temperature probe configured to measure a temperature value, the plurality of parameters comprising the temperature value.

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