WO2023094452A1 - Method and system for estimating a total pitch angle of a motor vehicle. - Google Patents

Method and system for estimating a total pitch angle of a motor vehicle. Download PDF

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Publication number
WO2023094452A1
WO2023094452A1 PCT/EP2022/082985 EP2022082985W WO2023094452A1 WO 2023094452 A1 WO2023094452 A1 WO 2023094452A1 EP 2022082985 W EP2022082985 W EP 2022082985W WO 2023094452 A1 WO2023094452 A1 WO 2023094452A1
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Prior art keywords
motor vehicle
module
pitch angle
estimating
sub
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PCT/EP2022/082985
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French (fr)
Inventor
Hassan Koulouh
Frédéric DUPONT
Cyril Rivier
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Aml Systems
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B60W40/10—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to vehicle motion
    • B60W40/11—Pitch movement
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Q—ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL
    • B60Q2300/00—Indexing codes for automatically adjustable headlamps or automatically dimmable headlamps
    • B60Q2300/10—Indexing codes relating to particular vehicle conditions
    • B60Q2300/13—Attitude of the vehicle body
    • B60Q2300/132—Pitch
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2520/00—Input parameters relating to overall vehicle dynamics
    • B60W2520/10—Longitudinal speed
    • B60W2520/105—Longitudinal acceleration

Definitions

  • the present disclosure deals with a method and a system for estimating a total pitch angle of a motor vehicle.
  • the pitch angle may be defined as being an angle between a longitudinal reference axis of the motor vehicle chassis and a longitudinal reference axis of the road on which the motor vehicle is intended to run. Indeed, the pitch angle can vary as a function of the load distribution in the motor vehicle and of its suspension system.
  • the emission angle of the light-beam can then be changed.
  • the current regulations prohibit excessive raising of the light-beam under certain road conditions, in particular in low beam, to avoid dazzling a driver of an oncoming motor vehicle. Consequently, a change of the emission angle of a light-beam, for example due to a particular load distribution in the motor vehicle, may in some cases lead to unauthorized glare. Therefore, a correction is necessary in such a case.
  • pitch angle sensors are known. At least one, and generally at least two, pitch angle sensors are provided on a motor vehicle. Such pitch angle sensors generally comprise a measuring element linked to two arms which are articulated and which are linked, respectively, to an element integral with the chassis of the motor vehicle and to an element integral with an axle of the motor vehicle. Such pitch angle sensors are expensive.
  • a purpose of the present disclosure is to overcome this disadvantage by proposing a method and a system for estimating the total pitch angle of a motor vehicle while the motor vehicle is running on a road.
  • the method and the system make it possible to determine and provide a particularly precise total pitch angle value in a stand-alone manner without excessive cost.
  • the disclosure herein relates to a method for estimating a total pitch angle of a motor vehicle while the motor vehicle is running along a path on a road, said total pitch angle corresponding to an angle between a longitudinal reference axis of a chassis of the motor vehicle and a longitudinal reference axis of the road on which the motor vehicle is intended to run, the motor vehicle having a suspensions system.
  • the method comprises at least the following steps:
  • the total pitch angle can be precisely estimated without excessive cost.
  • the method comprises a third estimating step, implemented by a third estimating module, consisting in estimating the static pitch angle when the motor vehicle is stationary and when the motor vehicle is running.
  • the transfer function of the suspension system is predetermined.
  • the method further comprises a first determining step preceding the first estimating step, the first determining step, implemented by a first determining module, consisting in determining an estimation of the transfer function of the suspension system.
  • the characteristic parameter is equal to a first predetermined characteristic parameter when the motor vehicle is in an acceleration phase, the characteristic parameter is equal to a second predetermined characteristic parameter when the motor vehicle is in a braking phase.
  • the method further comprises a second determining step preceding the first estimating step, the second determining step consisting in determining an estimation of the characteristic parameter,
  • the second determining step implemented by a second determining module, comprising the following sub-steps:
  • the first determining step and/or the second determining step are implemented while the motor vehicle 2 is running along.
  • the signal representative of the estimated total pitch angle corresponds to a command related to the estimated total pitch angle intended to command at least one actuator of the user device in order to change the orientation of the headlamp according to the estimated total pitch angle.
  • the command compensates known defaults of the user device.
  • the disclosure herein further relates to a system for estimating a total pitch angle of a motor vehicle while the motor vehicle is running along a path on a road, said total pitch angle corresponding to an angle between a longitudinal reference axis of a chassis of the motor vehicle and a longitudinal reference axis of the road on which the motor vehicle is intended to run, the motor vehicle having a suspensions system,
  • the system comprises at least:
  • corresponds to the pitch angle of the motor vehicle corresponds to the longitudinal acceleration of the motor vehicle measured by the accelerometer, corresponds to a characteristic parameter of the suspension system of the motor vehicle, corresponds to a transfer function of the suspension system;
  • the system comprises a third estimating module configured to estimate the static pitch angle when the motor vehicle is stationary and when the motor vehicle is running.
  • the system further comprises a first determining module, configured to determine an estimation of the transfer function of the suspension system.
  • the characteristic parameter is equal to a first predetermined characteristic parameter when the motor vehicle is in an acceleration phase, the characteristic parameter is equal to a second predetermined characteristic parameter when the motor vehicle is in a braking phase.
  • system further comprises a second determining module configured to determine an estimation of the characteristic parameter
  • the second determining module comprising:
  • the first determining module and/or the second determining module are configured to be implemented while the motor vehicle is running along.
  • the signal representative of the estimated total pitch angle corresponds to a command related to the estimated total pitch angle intended to command at least one actuator of the user device in order to change the orientation of the headlamp according to the estimated total pitch angle.
  • the command compensates known defaults of the user device.
  • FIG. 1 shows schematically a profile view of the motor vehicle running along on a road.
  • a motor vehicle 2 is schematically shown on figure 1 in a coordinate reference ( , , ).
  • the total pitch angle of a motor vehicle 2 has two components: the static pitch angle and the dynamic pitch angle .
  • the total pitch angle can be calculated by the following equation: .
  • the static pitch angle concerns the variation of the pitch angle due to the variation of the loading in the motor vehicle 2.
  • the dynamic pitch angle concerns the variation of the pitch angle due to acceleration or braking of the motor vehicle 2.
  • the method for estimating the total pitch angle is schematically shown on .
  • the method in intended to estimate a total pitch angle of a motor vehicle 2 while the motor vehicle 2 is running along a path on a road 3.
  • Said total pitch angle corresponds to an angle between a longitudinal reference axis A1 of a chassis 21 of the motor vehicle 2 and a longitudinal reference axis of the road 3 on which the motor vehicle 2 is intended to run.
  • the motor vehicle 2 has a suspensions system 4.
  • the method comprises at least the following steps:
  • the measuring step E1 is implemented by an accelerometer 5 on board the motor vehicle 2.
  • the measuring step E1 consists in measuring over time at least a longitudinal acceleration of the motor vehicle 2.
  • the accelerometer 5 can be a micro-electromechanical system (MEMS).
  • MEMS micro-electromechanical system
  • the estimating step E2 is implemented by an estimating module 6.
  • the estimating step E2 consists in estimating the dynamic pitch angle of the motor vehicle 2 thanks to the longitudinal acceleration measured in the measuring step E1 from the following equation: , wherein: corresponds to the dynamic pitch angle of the motor vehicle 2, corresponds to the longitudinal acceleration of the motor vehicle 2 measured by the accelerometer 5, corresponds to a characteristic parameter of the suspension system 4 of the motor vehicle 2, corresponds to a transfer function of the suspension system 4.
  • the longitudinal acceleration is in g unit in which 1 g is equal to the gravity acceleration.
  • the gravity acceleration is approximately equal to 9.8 m/s 2 .
  • the longitudinal acceleration corresponds to the sum of the actual acceleration of the motor vehicle 2 and the inclination (or slope) of the road on which the motor vehicle is running along.
  • the longitudinal acceleration can be calculated by the following equation: .
  • the estimating step E3 is implemented by an estimating module 6.
  • the estimating step E3 consists in estimating the total pitch angle .
  • the total pitch angle is equal to the sum of the dynamic pitch angle estimated in the estimating step E2 and a static pitch angle corresponding to a pitch angle when the motor vehicle 2 is stationary.
  • the transmitting step E4 is implemented by a transmitting module 63.
  • the transmitting step E4 consists in elaborating and transmitting a signal representative of the estimated total pitch angle estimated in the estimating step E3 to a user device HL.
  • the user device can be a headlamp control system of the motor vehicle 2.
  • the signal representative of the estimated total pitch angle can correspond to a signal representative of the value of the estimated total pitch angle .
  • the signal representative of the estimated total pitch angle can correspond to a command related to the estimated total pitch angle intended to command at least one actuator of the user device HL in order to change the orientation of the headlamp according to the estimated total pitch angle .
  • the command can compensate known defaults of the user device HL.
  • the command can take into account the delay between the determination of the command and the execution of the command.
  • the method can comprise an estimating step E21 implemented by an estimating module 61.
  • the estimating step consists in estimating the static pitch angle when the motor vehicle 2 is stationary and when the motor vehicle 2 is running along.
  • the static pitch angle varies as a function of the loading variations on the motor vehicle 2.
  • the variations of the static pitch angle can be estimated by the estimating module 61 during the loading of the motor vehicle 2 when the motor vehicle 2 is stationary.
  • the variations of the static pitch angle can also be estimated by the estimating module 61 when the motor vehicle 2 is running along.
  • the two ways can be combined: the variations of the static pitch angle can then be estimated when the motor vehicle 2 is stationary and when the motor vehicle 2 is running along. Estimating the variations of the static pitch angle during the loading of the motor vehicle 2 when the motor vehicle 2 is stationary and when the motor vehicle 2 is running along provides a reliable estimation of the variations of the static pitch angle .
  • the estimating module 61 can comprise the accelerometer which is configured to measure the longitudinal acceleration and the vertical acceleration and, optionally, the gyrometer which is configured to measure gyrometric values.
  • the gyrometric values can be used by the estimating module 61 at least for eliminating paths that are insufficiently rectilinear.
  • the static pitch angle can be estimated as follows. A plurality of measurement sets is measured by the accelerometer. Each measurement set comprises a measurement of the longitudinal acceleration and a measurement of the vertical acceleration. The longitudinal acceleration and the vertical acceleration are linked together by a proportionality coefficient that depends on the static pitch angle . A plurality of proportionality coefficients is determined by a linear regression on the plurality of measurement sets. The static pitch angle is then estimated from the proportionality coefficients.
  • the dynamic pitch angle ⁇ is determined from the following equation: .
  • the characteristic parameter depends on whether the motor vehicle is in an acceleration phase or a braking phase.
  • the acceleration phase the acceleration of the motor vehicle 2 is positive.
  • the braking phase the acceleration of the motor vehicle 2 is negative.
  • the transfer function of the suspension system 4 takes into account the response time and damping in the changes of the dynamic pitch angle when the motor vehicle 2 is braking hard and briefly or when the motor vehicle 2 is accelerating strongly and briefly.
  • the transfer function depends on the type of the motor vehicle.
  • the transfer function can be a second-order transfer function.
  • the transfer function of the suspension system 4 can be provided by the motor vehicle manufacturer.
  • the transfer function can vary over time according to the aging of the suspension system 4.
  • the characteristic parameter and/or the transfer function of the suspension system 4 can be predetermined.
  • the characteristic parameter and/or the transfer function can be provided by the vehicle manufacturer.
  • the characteristic parameter can also be predetermined “off-line” from a plurality of measuring points of the total pitch angle made from external measurement sensors S1, S2 during experimental tests.
  • the plurality of measuring points made from external measurement sensors S1, S2 are then compared to a plurality of measuring points determined from the accelerometer. Determining “off-line” means that the characteristic parameter is predetermined for each type of motor vehicle 2.
  • the external measurement sensors S1, S2 may comprise four laser sensors S1, S2, each sensor S1, S2 is dedicated respectively to a wheel W1, W2 of the motor vehicle 2.
  • the total pitch angle corresponds to a pitch angle of the motor vehicle 2 in relation to the road 3.
  • the total pitch angle does not take the slope of the road 3 into account.
  • Each laser sensor S1, S2 determines the distance d1, d2 between the chassis 21 and the axle E1, E2 extremity on which the wheel W1, W2 is fixed (the laser sensors S1, S2 point at the axles E1, E2).
  • the distance W between the axles E1 and E2 is known.
  • the following equation can be obtained: .
  • For small angles, can be approximated as follows: .
  • the following equation can be used: .
  • the laser sensors S1, S2 can determines the distance d1 and d2 between the chassis 21 and the road 3 in case the road is smooth and reflective (the laser sensors S1, S2 point at the road 3). The same equation can be used.
  • the crushing of the tyres of the wheels W1, W2 can be compensated.
  • the compensation can be between 5% to 10%.
  • the variation of the actual total pitch angle allows the determination of the predetermined characteristic parameter thanks to the following equation , wherein corresponds to the static pitch angle.
  • the longitudinal acceleration is measured by the accelerometer 5.
  • the characteristic parameter is predetermined from a plurality of measuring points of dynamic pitch angle made from external measurement sensors S1, S2 during experimental tests when the motor vehicle 2 is in the acceleration phase and when the motor vehicle is in the braking phase.
  • the static pitch angle can be determined when the motor vehicle 2 is stationary and when the motor vehicle 2 is running along.
  • the characteristic parameter is equal to a first predetermined characteristic parameter when the motor vehicle 2 is in the acceleration phase.
  • the characteristic parameter is equal to a second predetermined characteristic parameter when the motor vehicle 2 is in the braking phase.
  • the transfer function of the suspension system 4 is predetermined from a plurality of measuring points of dynamic pitch angle made from external measurement sensors S1, S2 during experimental tests. The times of response and the damping are determined when the motor vehicle 2 is braking hard and briefly or when the motor vehicle 2 is accelerating strongly and briefly, so as to obtain the transfer function of the suspension system 4.
  • the plurality of measuring points of dynamic pitch angle made from external measurement sensors S1, S2 are compared to the plurality of measuring points of dynamic pitch angle determined from the accelerometer.
  • a post-processing allows to identified the first predetermined characteristic parameter , the second predetermined characteristic parameter and the transfer function that fit the best between the total pitch angle measured by the external measurements and the total pitch angle calculated from the longitudinal acceleration measured by the accelerometer.
  • a graph shows the total pitch angle as a function of time T (in s) for the third non-limited example.
  • Curve C1 full line
  • Curve C2 (dotted line) is obtained from the plurality of measuring points determined from the accelerometer.
  • the characteristic parameter and/or the transfer function of the suspension system 4 are determined “on-line”. Determining “on-line” means that the characteristic parameter is continuously determined on the motor vehicle 2 while the motor vehicle 2 is used. Determining “off-line” of the second variant of the first embodiment and determining “on-line” can be combined.
  • the second embodiment corresponds to a statistical estimation based on an analysis of a set of acceleration and brake phases over time.
  • the method further comprises a determining step E11 preceding the estimating step E2.
  • the determining step E11 is implemented by a determining module 51.
  • Said determining step E11 consists in determining an estimation of the transfer function of the suspension system 4.
  • the method further comprises a determining step E12 preceding the estimating step E2.
  • the determining step E12 consists in determining an estimation of the characteristic parameter .
  • the determining step E12 is implemented by a determining module 52. It comprises the following sub-steps:
  • the measuring sub-step E121 is implemented by a gyrometer 7 on board the motor vehicle 2.
  • the measuring sub-step E121 consists in measuring over time angle variations of the motor vehicle 2.
  • the angle variations measured by the gyrometer 7 correspond to pitch variations.
  • the filtering sub-step E122 is implemented by a filtering sub-module 8. consisting in filtering the angle variations measured in the measuring sub-step E121.
  • the aggregating sub-step E123 is implemented by an aggregating sub-module 9.
  • the aggregating sub-step E123 consists in aggregating the angle variations filtered in the filtering sub-step E122 when the motor vehicle 2 is in an acceleration phase as a function of an estimation of a relevance of the filtered angle variations.
  • the relevance can be a predetermined relevance.
  • the aggregating sub-step E124 is implemented by an aggregating sub-module 10.
  • the aggregating sub-step E124 consists in aggregating the angle of variations filtered in the filtered sub-step E122 when the motor vehicle 2 is in a brake phase as a function of an estimation of the relevance of the filtered angle variation.
  • the relevance can be a predetermined relevance.
  • the comparison sub-step E125 is implemented by a comparison sub-module 11.
  • the comparison sub-step E125 consists in comparing the aggregated angle variations when the motor vehicle 2 is in an acceleration phase to the longitudinal acceleration ⁇ of the motor vehicle 2 measured in the measuring step E1 when the motor vehicle 2 is in the acceleration phase.
  • the comparison sub-step E125 consists in comparing the aggregated angle variations when the motor vehicle 2 is in an acceleration phase to the variations of the total pitch angle calculated from the longitudinal acceleration ⁇ of the motor vehicle 2 measured in the measuring step E1 when the motor vehicle 2 is in the acceleration phase.
  • the comparison sub-step E126 is implemented by a comparison sub-module 12.
  • the comparison sub-step E126 consists in comparing the aggregated angle variations when the motor vehicle 2 is in the brake phase to the longitudinal acceleration ⁇ of the motor vehicle 2 measured in the measuring step E1 when the motor vehicle 2 is in the brake phase.
  • the comparison sub-step E126 consists in comparing the aggregated angle variations when the motor vehicle 2 is in a brake phase to the variations of the total pitch angle calculated from the longitudinal acceleration ⁇ of the motor vehicle 2 measured in the measuring step E1 when the motor vehicle 2 is in the brake phase.
  • the estimating sub-step E127 is implemented by an estimating sub-module 13.
  • the estimating sub-step E127 consists in estimating, from the comparison implemented in the comparison sub-step E126 a first characteristic parameter corresponding to the characteristic parameter when the motor vehicle 2 is in an acceleration phase.
  • a quality of the estimation of the first characteristic parameter can be also provided in the estimating sub-step E127.
  • the estimating sub-step E128 is implemented by an estimating sub-module 14.
  • the estimating sub-step E128 consists in estimating from the comparison implemented in the comparison sub-step E126 a second characteristic parameter corresponding to the characteristic parameter when the motor vehicle 2 is in a braking phase.
  • a quality of the estimation of the second characteristic parameter can be also provided in the estimating sub-step E128.
  • a graph shows the variation angle as a function of time T (in s).
  • Curve C3 (in full line) is obtained by the angle variations measured by the gyrometer 7 in an acceleration phase.
  • Curve C4 (in dotted line) is obtained by the variations of the total pitch angle calculated from the longitudinal acceleration ⁇ .
  • the first characteristic parameter is 3.71.
  • a graph shows the variation angle as a function of time T (in s).
  • Curve C5 full line
  • Curve C6 (dotted line) is obtained by the variations of the total pitch angle calculated from the longitudinal acceleration ⁇ .
  • the second characteristic parameter is 2.31.
  • the “on-line determination” allows wear of the suspension system 4 to be taken into account.
  • the first predetermined characteristic parameter and the second predetermined characteristic parameter vary as a function of the loading since the motor vehicle 2 is heavier and closer to the road 3. The variation is taken into account.
  • the disclosure further deals with a system 1 for estimating a total pitch angle of a motor vehicle 2 while the motor vehicle 2 is running along a path on a road 3.
  • the system comprises at least:
  • the system 1 may further comprise comprises a determining module 51, configured to determine an estimation of the transfer function of the suspension system.
  • the system 1 may further comprise a determining module 52 configured to determine an estimation of the characteristic parameter .
  • the determining module 52 may comprise:
  • the quality of the estimation of the first characteristic parameter can be also provided by the estimating sub-module 13.
  • the quality of the estimation of the second characteristic parameter can be also provided by the estimating sub-module 14.
  • the estimating method and system can be specific in that:

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Abstract

- Method and system for estimating a total pitch angle of a motor vehicle. - The method comprises a measuring step (E1) for measuring over time a longitudinal acceleration (E) of the motor vehicle (2), an estimating step (E2) for estimating a dynamic pitch angle (a) of the motor vehicle (2) from the longitudinal acceleration (E) of the motor vehicle (2) and an estimating step (E3) for estimating the total pitch angle.

Description

Method and system for estimating a total pitch angle of a motor vehicle.
The present disclosure deals with a method and a system for estimating a total pitch angle of a motor vehicle.
 BACKGROUND
In order to perform a correction of a headlamp light-beam of a motor vehicle, it may be necessary to know the exact variations of the pitch angle of the motor vehicle. The pitch angle may be defined as being an angle between a longitudinal reference axis of the motor vehicle chassis and a longitudinal reference axis of the road on which the motor vehicle is intended to run. Indeed, the pitch angle can vary as a function of the load distribution in the motor vehicle and of its suspension system. The emission angle of the light-beam can then be changed. The current regulations prohibit excessive raising of the light-beam under certain road conditions, in particular in low beam, to avoid dazzling a driver of an oncoming motor vehicle. Consequently, a change of the emission angle of a light-beam, for example due to a particular load distribution in the motor vehicle, may in some cases lead to unauthorized glare. Therefore, a correction is necessary in such a case.
To determine the pitch angle of the motor vehicle, pitch angle sensors are known. At least one, and generally at least two, pitch angle sensors are provided on a motor vehicle. Such pitch angle sensors generally comprise a measuring element linked to two arms which are articulated and which are linked, respectively, to an element integral with the chassis of the motor vehicle and to an element integral with an axle of the motor vehicle. Such pitch angle sensors are expensive.
Also, to reduce the cost, it is advantageous to be able to determine the pitch angle of the motor vehicle from other means.
 SUMMARY
A purpose of the present disclosure is to overcome this disadvantage by proposing a method and a system for estimating the total pitch angle of a motor vehicle while the motor vehicle is running on a road. The method and the system make it possible to determine and provide a particularly precise total pitch angle value in a stand-alone manner without excessive cost.
For this purpose, the disclosure herein relates to a method for estimating a total pitch angle of a motor vehicle while the motor vehicle is running along a path on a road, said total pitch angle corresponding to an angle between a longitudinal reference axis of a chassis of the motor vehicle and a longitudinal reference axis of the road on which the motor vehicle is intended to run, the motor vehicle having a suspensions system.
According to the disclosure herein, the method comprises at least the following steps:
  • a first measuring step, implemented by an accelerometer on board the motor vehicle, consisting in measuring over time at least a longitudinal acceleration of the motor vehicle;
  • a first estimating step, implemented by a first estimating module, consisting in estimating a dynamic pitch angle of the motor vehicle thanks to the longitudinal acceleration measured in the measuring step from the following equation:
Figure pctxmlib-appb-M000001
, wherein:
Figure pctxmlib-appb-M000002
 corresponds to the dynamic pitch angle of the motor vehicle,
Figure pctxmlib-appb-M000003
 corresponds to the longitudinal acceleration of the motor vehicle measured by the accelerometer,
Figure pctxmlib-appb-M000004
 corresponds to a characteristic parameter of the suspension system of the motor vehicle,
Figure pctxmlib-appb-M000005
 corresponds to a transfer function of the suspension system;
  • a second estimating step, implemented by a second estimating module, consisting in estimating the total pitch angle, the total pitch angle being equal to the sum of the dynamic pitch angle estimated in the first estimating step and a static pitch angle corresponding to a pitch angle when the motor vehicle is stationary;
  • a transmitting step, implemented by a transmitting module, consisting in transmitting a signal representative of the estimated total pitch angle to a user device.
Thus, thanks to the method, the total pitch angle can be precisely estimated without excessive cost.
For example, the method comprises a third estimating step, implemented by a third estimating module, consisting in estimating the static pitch angle when the motor vehicle is stationary and when the motor vehicle is running.
In a non-limitative example, the transfer function of the suspension system is predetermined.
According to an embodiment, the method further comprises a first determining step preceding the first estimating step, the first determining step, implemented by a first determining module, consisting in determining an estimation of the transfer function of the suspension system.
According to an embodiment, the characteristic parameter is equal to a first predetermined characteristic parameter when the motor vehicle is in an acceleration phase, the characteristic parameter is equal to a second predetermined characteristic parameter when the motor vehicle is in a braking phase.
According to another embodiment, the method further comprises a second determining step preceding the first estimating step, the second determining step consisting in determining an estimation of the characteristic parameter,
the second determining step, implemented by a second determining module, comprising the following sub-steps:
  • a measuring sub-step, implemented by a gyrometer on board the motor vehicle, consisting in measuring over time angle variations of the motor vehicle;
  • a filtering sub-step, implemented by a filtering sub-module, consisting in filtering the angle variations measured in the measuring sub-step;
  • a first aggregating sub-step, implemented by a first aggregating sub-module, consisting in aggregating the angle variations filtered in the filtering sub-step when the motor vehicle is in an acceleration phase as a function of an estimation of a relevance of the filtered angle variations;
  • a second aggregating sub-step, implemented by a second aggregating sub-module, consisting in aggregating the angle of variations filtered in the filtered sub-step when the motor vehicle is in a brake phase as a function of an estimation of the relevance of the filtered angle variation;
  • a first comparison sub-step, implemented by a first comparison sub-module, consisting in comparing the aggregated angle variations when the motor vehicle is in an acceleration phase to the longitudinal acceleration of the motor vehicle measured in the first measuring step when the motor vehicle is in the acceleration phase;
  • a second comparison sub-step, implemented by a second comparison sub-module, consisting in comparing the aggregated angle variations when the motor vehicle is in the brake phase to the longitudinal acceleration (
    Figure pctxmlib-appb-M000006
    ) of the motor vehicle measured in the first measuring step when the motor vehicle is in the brake phase;
  • a first estimating sub-step, implemented by a first estimating sub-module, consisting in estimating, from the comparison implemented in the comparison sub-step, a first characteristic parameter corresponding to the characteristic parameter when the motor vehicle is in an acceleration phase;
  • a second estimating sub-step, implemented by a second estimating sub-module, consisting in estimating from the comparison implemented in the second comparison sub-step, a second characteristic parameter corresponding to the characteristic parameter when the motor vehicle is in a braking phase.
In a variant, the first determining step and/or the second determining step are implemented while the motor vehicle 2 is running along.
Moreover, the signal representative of the estimated total pitch angle corresponds to a command related to the estimated total pitch angle intended to command at least one actuator of the user device in order to change the orientation of the headlamp according to the estimated total pitch angle.
For example, the command compensates known defaults of the user device.
The disclosure herein further relates to a system for estimating a total pitch angle of a motor vehicle while the motor vehicle is running along a path on a road, said total pitch angle corresponding to an angle between a longitudinal reference axis of a chassis of the motor vehicle and a longitudinal reference axis of the road on which the motor vehicle is intended to run, the motor vehicle having a suspensions system,
According to the disclosure herein, the system comprises at least:
  • an accelerometer on board the motor vehicle configured to measure over time at least a longitudinal acceleration of the motor vehicle;
  • a first estimating module configured to estimate a dynamic pitch angle of the motor vehicle thanks to the longitudinal acceleration measured by the accelerometer from the following equation:
Figure pctxmlib-appb-M000007
, wherein:
Figure pctxmlib-appb-M000008
 corresponds to the pitch angle of the motor vehicle,
Figure pctxmlib-appb-M000009
 corresponds to the longitudinal acceleration of the motor vehicle measured by the accelerometer,
Figure pctxmlib-appb-M000010
 corresponds to a characteristic parameter of the suspension system of the motor vehicle,
Figure pctxmlib-appb-M000011
 corresponds to a transfer function of the suspension system;
  • a second estimating module configured to estimate the total pitch angle, the total pitch angle being equal to the sum of the dynamic pitch angle estimated by the first estimating module and a static pitch angle corresponding to a pitch angle when the motor vehicle is stationary;
  • a transmitting module configured to transmit a signal representative of the estimated total pitch angle to a user device.
For example, the system comprises a third estimating module configured to estimate the static pitch angle when the motor vehicle is stationary and when the motor vehicle is running.
According to an embodiment, the system further comprises a first determining module, configured to determine an estimation of the transfer function of the suspension system.
According to an embodiment, the characteristic parameter is equal to a first predetermined characteristic parameter when the motor vehicle is in an acceleration phase, the characteristic parameter is equal to a second predetermined characteristic parameter when the motor vehicle is in a braking phase.
According to another embodiment, the system further comprises a second determining module configured to determine an estimation of the characteristic parameter,
the second determining module comprising:
  • a gyrometer on board the motor vehicle configured to measure over time angle variations of the motor vehicle;
  • a filtering sub-module configured to filter the angle variations measured in by the gyrometer;
  • a first aggregating sub-module configured to aggregate the angle variations filtered by the filtering sub-module when the motor vehicle is in an acceleration phase as a function of an estimation of a relevance of the filtered angle variations;
  • a second aggregating sub-module configured to aggregate the angle of variations filtered by the filtered sub-module when the motor vehicle is in a brake phase as a function of an estimation of the relevance of the filtered angle variation;
  • a first comparison sub-module configured to compare the aggregated angle variations when the motor vehicle is in an acceleration phase to the longitudinal acceleration of the motor vehicle measured by the accelerometer when the motor vehicle is in the acceleration phase;
  • a second comparison sub-module configured to compare the aggregated angle variations when the motor vehicle is in the brake phase to the longitudinal acceleration of the motor vehicle measured by the accelerometer when the motor vehicle is in the brake phase;
  • a first estimating sub-module configured to estimate, from the comparison implemented by the first comparison sub-module, a first characteristic parameter corresponding to the characteristic parameter when the motor vehicle is in an acceleration phase;
  • a second estimating sub-module configured to estimate from the comparison implemented by the second comparison sub-module, a second characteristic parameter when the motor vehicle is in a braking phase.
In a variant, the first determining module and/or the second determining module are configured to be implemented while the motor vehicle is running along.
Moreover, the signal representative of the estimated total pitch angle corresponds to a command related to the estimated total pitch angle intended to command at least one actuator of the user device in order to change the orientation of the headlamp according to the estimated total pitch angle.
For example, the command compensates known defaults of the user device.
 BRIEF DESCRIPTION OF THE DRAWINGS
The disclosure herein, with its features and advantages, will emerge more clearly on reading the description given with reference to the appended drawings in which:
shows schematically a profile view of the motor vehicle running along on a road.
shows schematically the method for estimating the pitch angle of the motor vehicle.
shows schematically the system for estimating the pitch angle of the motor vehicle.
is a graph showing the total pitch angle as a function of time s.
is a graph showing the variation angle as a function of time s in an acceleration phase.
is a graph showing the variation angle as a function of time s in a brake phase.
 DETAILED DESCRIPTION
A motor vehicle 2 is schematically shown on figure 1 in a coordinate reference (
Figure pctxmlib-appb-M000012
,
Figure pctxmlib-appb-M000013
,
Figure pctxmlib-appb-M000014
).
The total pitch angle
Figure pctxmlib-appb-M000015
 of a motor vehicle 2 has two components: the static pitch angle
Figure pctxmlib-appb-M000016
 and the dynamic pitch angle
Figure pctxmlib-appb-M000017
. The total pitch angle
Figure pctxmlib-appb-M000018
 can be calculated by the following equation:
Figure pctxmlib-appb-M000019
.
The static pitch angle
Figure pctxmlib-appb-M000020
 concerns the variation of the pitch angle due to the variation of the loading in the motor vehicle 2. The dynamic pitch angle
Figure pctxmlib-appb-M000021
 concerns the variation of the pitch angle due to acceleration or braking of the motor vehicle 2.
The method for estimating the total pitch angle
Figure pctxmlib-appb-M000022
 is schematically shown on .
The method in intended to estimate a total pitch angle
Figure pctxmlib-appb-M000023
 of a motor vehicle 2 while the motor vehicle 2 is running along a path on a road 3.
Said total pitch angle
Figure pctxmlib-appb-M000024
 corresponds to an angle between a longitudinal reference axis A1 of a chassis 21 of the motor vehicle 2 and a longitudinal reference axis of the road 3 on which the motor vehicle 2 is intended to run. The motor vehicle 2 has a suspensions system 4.
The method comprises at least the following steps:
  • a measuring step E1;
  • an estimating step E2;
  • an estimating step E3;
  • a transmitting step E4.
The measuring step E1 is implemented by an accelerometer 5 on board the motor vehicle 2. The measuring step E1 consists in measuring over time at least a longitudinal acceleration
Figure pctxmlib-appb-M000025
 of the motor vehicle 2.
The accelerometer 5 can be a micro-electromechanical system (MEMS).
The estimating step E2 is implemented by an estimating module 6. The estimating step E2 consists in estimating the dynamic pitch angle
Figure pctxmlib-appb-M000026
 of the motor vehicle 2 thanks to the longitudinal acceleration
Figure pctxmlib-appb-M000027
 measured in the measuring step E1 from the following equation:
Figure pctxmlib-appb-M000028
, wherein:
Figure pctxmlib-appb-M000029
 corresponds to the dynamic pitch angle of the motor vehicle 2,
Figure pctxmlib-appb-M000030
 corresponds to the longitudinal acceleration of the motor vehicle 2 measured by the accelerometer 5,
Figure pctxmlib-appb-M000031
 corresponds to a characteristic parameter of the suspension system 4 of the motor vehicle 2,
Figure pctxmlib-appb-M000032
 corresponds to a transfer function of the suspension system 4.
The longitudinal acceleration
Figure pctxmlib-appb-M000033
 is in g unit in which 1 g is equal to the gravity acceleration. The gravity acceleration is approximately equal to 9.8 m/s2.
The longitudinal acceleration
Figure pctxmlib-appb-M000034
 corresponds to the sum of the actual acceleration
Figure pctxmlib-appb-M000035
 of the motor vehicle 2 and the inclination (or slope)
Figure pctxmlib-appb-M000036
 of the road on which the motor vehicle is running along. The longitudinal acceleration
Figure pctxmlib-appb-M000037
 can be calculated by the following equation:
Figure pctxmlib-appb-M000038
.
The estimating step E3 is implemented by an estimating module 6. The estimating step E3 consists in estimating the total pitch angle
Figure pctxmlib-appb-M000039
. The total pitch angle
Figure pctxmlib-appb-M000040
 is equal to the sum of the dynamic pitch angle
Figure pctxmlib-appb-M000041
 estimated in the estimating step E2 and a static pitch angle
Figure pctxmlib-appb-M000042
 corresponding to a pitch angle when the motor vehicle 2 is stationary.
The transmitting step E4 is implemented by a transmitting module 63. The transmitting step E4 consists in elaborating and transmitting a signal representative of the estimated total pitch angle
Figure pctxmlib-appb-M000043
 estimated in the estimating step E3 to a user device HL. The user device can be a headlamp control system of the motor vehicle 2.
According to a variant, the signal representative of the estimated total pitch angle
Figure pctxmlib-appb-M000044
 can correspond to a signal representative of the value of the estimated total pitch angle
Figure pctxmlib-appb-M000045
.
According to another variant, the signal representative of the estimated total pitch angle
Figure pctxmlib-appb-M000046
 can correspond to a command related to the estimated total pitch angle
Figure pctxmlib-appb-M000047
 intended to command at least one actuator of the user device HL in order to change the orientation of the headlamp according to the estimated total pitch angle
Figure pctxmlib-appb-M000048
. The command can compensate known defaults of the user device HL. For example, the command can take into account the delay between the determination of the command and the execution of the command.
The method can comprise an estimating step E21 implemented by an estimating module 61. The estimating step consists in estimating the static pitch angle
Figure pctxmlib-appb-M000049
 when the motor vehicle 2 is stationary and when the motor vehicle 2 is running along. The static pitch angle
Figure pctxmlib-appb-M000050
 varies as a function of the loading variations on the motor vehicle 2. According to a first way, the variations of the static pitch angle
Figure pctxmlib-appb-M000051
 can be estimated by the estimating module 61 during the loading of the motor vehicle 2 when the motor vehicle 2 is stationary. According to a second way, the variations of the static pitch angle
Figure pctxmlib-appb-M000052
 can also be estimated by the estimating module 61 when the motor vehicle 2 is running along. The two ways can be combined: the variations of the static pitch angle
Figure pctxmlib-appb-M000053
 can then be estimated when the motor vehicle 2 is stationary and when the motor vehicle 2 is running along. Estimating the variations of the static pitch angle
Figure pctxmlib-appb-M000054
 during the loading of the motor vehicle 2 when the motor vehicle 2 is stationary and when the motor vehicle 2 is running along provides a reliable estimation of the variations of the static pitch angle
Figure pctxmlib-appb-M000055
.
The estimating module 61 can comprise the accelerometer which is configured to measure the longitudinal acceleration and the vertical acceleration and, optionally, the gyrometer which is configured to measure gyrometric values. The gyrometric values can be used by the estimating module 61 at least for eliminating paths that are insufficiently rectilinear. The static pitch angle
Figure pctxmlib-appb-M000056
 can be estimated as follows. A plurality of measurement sets is measured by the accelerometer. Each measurement set comprises a measurement of the longitudinal acceleration and a measurement of the vertical acceleration. The longitudinal acceleration and the vertical acceleration are linked together by a proportionality coefficient that depends on the static pitch angle
Figure pctxmlib-appb-M000057
. A plurality of proportionality coefficients is determined by a linear regression on the plurality of measurement sets. The static pitch angle
Figure pctxmlib-appb-M000058
 is then estimated from the proportionality coefficients.
The dynamic pitch angle α is determined from the following equation:
Figure pctxmlib-appb-M000059
.
The characteristic parameter
Figure pctxmlib-appb-M000060
 depends on whether the motor vehicle is in an acceleration phase or a braking phase. In the acceleration phase, the acceleration of the motor vehicle 2 is positive. In the braking phase, the acceleration of the motor vehicle 2 is negative.
The characteristic parameter can vary according to:
  • an estimated loading of the motor vehicle 2,
  • information of the motor vehicle 2 indicating the suspension mode (especially for all-terrain motor vehicle 2 that can have normal road mode, mode for road with snow, mode for road with sand, etc.),
  • the aging of the suspension system 4 over time.
The transfer function
Figure pctxmlib-appb-M000061
 of the suspension system 4 takes into account the response time and damping in the changes of the dynamic pitch angle
Figure pctxmlib-appb-M000062
 when the motor vehicle 2 is braking hard and briefly or when the motor vehicle 2 is accelerating strongly and briefly.
The transfer function
Figure pctxmlib-appb-M000063
 depends on the type of the motor vehicle. For example, the transfer function
Figure pctxmlib-appb-M000064
 can be a second-order transfer function. The transfer function
Figure pctxmlib-appb-M000065
 of the suspension system 4 can be provided by the motor vehicle manufacturer.
The transfer function
Figure pctxmlib-appb-M000066
 can vary over time according to the aging of the suspension system 4.
According to a first variant of a first embodiment, the characteristic parameter
Figure pctxmlib-appb-M000067
 and/or the transfer function
Figure pctxmlib-appb-M000068
 of the suspension system 4 can be predetermined. The characteristic parameter
Figure pctxmlib-appb-M000069
 and/or the transfer function
Figure pctxmlib-appb-M000070
 can be provided by the vehicle manufacturer.
According to a second variant, the characteristic parameter
Figure pctxmlib-appb-M000071
 can also be predetermined “off-line” from a plurality of measuring points of the total pitch angle
Figure pctxmlib-appb-M000072
 made from external measurement sensors S1, S2 during experimental tests. The plurality of measuring points made from external measurement sensors S1, S2 are then compared to a plurality of measuring points determined from the accelerometer. Determining “off-line” means that the characteristic parameter
Figure pctxmlib-appb-M000073
 is predetermined for each type of motor vehicle 2. The external measurement sensors S1, S2 may comprise four laser sensors S1, S2, each sensor S1, S2 is dedicated respectively to a wheel W1, W2 of the motor vehicle 2.
The total pitch angle
Figure pctxmlib-appb-M000074
 corresponds to a pitch angle of the motor vehicle 2 in relation to the road 3. The total pitch angle
Figure pctxmlib-appb-M000075
 does not take the slope of the road 3 into account.
On , two wheels W1 and W2 and two sensors S1, S2 are shown on the right side of the motor vehicle 2. Each laser sensor S1, S2 determines the distance d1, d2 between the chassis 21 and the axle E1, E2 extremity on which the wheel W1, W2 is fixed (the laser sensors S1, S2 point at the axles E1, E2).
The distance W between the axles E1 and E2 is known. The following equation can be obtained:
Figure pctxmlib-appb-M000076
. For small angles,
Figure pctxmlib-appb-M000077
 can be approximated as follows:
Figure pctxmlib-appb-M000078
. Thus, the following equation can be used:
Figure pctxmlib-appb-M000079
.
Then the variation of the four distances d1, d2 directly gives the variation of the actual total pitch angle
Figure pctxmlib-appb-M000080
.
In a variant, the laser sensors S1, S2 can determines the distance d1 and d2 between the chassis 21 and the road 3 in case the road is smooth and reflective (the laser sensors S1, S2 point at the road 3). The same equation can be used.
When the laser sensors S1, S2 point at the axle E1, E2 and do not point at the road, the crushing of the tyres of the wheels W1, W2 can be compensated. The compensation can be between 5% to 10%.
The variation of the actual total pitch angle
Figure pctxmlib-appb-M000081
 allows the determination of the predetermined characteristic parameter
Figure pctxmlib-appb-M000082
 thanks to the following equation
Figure pctxmlib-appb-M000083
, wherein
Figure pctxmlib-appb-M000084
 corresponds to the static pitch angle. The longitudinal acceleration
Figure pctxmlib-appb-M000085
 is measured by the accelerometer 5.
The characteristic parameter
Figure pctxmlib-appb-M000086
 is predetermined from a plurality of measuring points of dynamic pitch angle
Figure pctxmlib-appb-M000087
 made from external measurement sensors S1, S2 during experimental tests when the motor vehicle 2 is in the acceleration phase and when the motor vehicle is in the braking phase. The static pitch angle
Figure pctxmlib-appb-M000088
 can be determined when the motor vehicle 2 is stationary and when the motor vehicle 2 is running along.
The characteristic parameter
Figure pctxmlib-appb-M000089
 is equal to a first predetermined characteristic parameter
Figure pctxmlib-appb-M000090
 when the motor vehicle 2 is in the acceleration phase. The characteristic parameter
Figure pctxmlib-appb-M000091
 is equal to a second predetermined characteristic parameter
Figure pctxmlib-appb-M000092
 when the motor vehicle 2 is in the braking phase.
As a non-limited example,
Figure pctxmlib-appb-M000093
 and
Figure pctxmlib-appb-M000094
.
According to the first embodiment, the transfer function
Figure pctxmlib-appb-M000095
 of the suspension system 4 is predetermined from a plurality of measuring points of dynamic pitch angle
Figure pctxmlib-appb-M000096
 made from external measurement sensors S1, S2 during experimental tests. The times of response and the damping are determined when the motor vehicle 2 is braking hard and briefly or when the motor vehicle 2 is accelerating strongly and briefly, so as to obtain the transfer function
Figure pctxmlib-appb-M000097
 of the suspension system 4.
The plurality of measuring points of dynamic pitch angle
Figure pctxmlib-appb-M000098
 made from external measurement sensors S1, S2 are compared to the plurality of measuring points of dynamic pitch angle
Figure pctxmlib-appb-M000099
 determined from the accelerometer.
From the plurality of measuring points of dynamic pitch angle
Figure pctxmlib-appb-M000100
 made from external measurement sensors S1, S2 and from the plurality of measuring points determined from the accelerometer, a post-processing allows to identified the first predetermined characteristic parameter
Figure pctxmlib-appb-M000101
, the second predetermined characteristic parameter
Figure pctxmlib-appb-M000102
 and the transfer function
Figure pctxmlib-appb-M000103
 that fit the best between the total pitch angle measured by the external measurements and the total pitch angle calculated from the longitudinal acceleration
Figure pctxmlib-appb-M000104
 measured by the accelerometer.
As a first non-limited example,
Figure pctxmlib-appb-M000105
,
Figure pctxmlib-appb-M000106
 and
Figure pctxmlib-appb-M000107
As a second non-limited example,
Figure pctxmlib-appb-M000108
,
Figure pctxmlib-appb-M000109
 and
Figure pctxmlib-appb-M000110
As a third non-limited example,
Figure pctxmlib-appb-M000111
,
Figure pctxmlib-appb-M000112
 and
Figure pctxmlib-appb-M000113
On figure 4, a graph shows the total pitch angle
Figure pctxmlib-appb-M000114
 as a function of time T (in s) for the third non-limited example. Curve C1 (full line) is obtained from the plurality of measuring points of dynamic pitch angle
Figure pctxmlib-appb-M000115
 made from external measurement sensors S1, S2. Curve C2 (dotted line) is obtained from the plurality of measuring points determined from the accelerometer.
According to a second embodiment, the characteristic parameter
Figure pctxmlib-appb-M000116
 and/or the transfer function
Figure pctxmlib-appb-M000117
 of the suspension system 4 are determined “on-line”. Determining “on-line” means that the characteristic parameter
Figure pctxmlib-appb-M000118
 is continuously determined on the motor vehicle 2 while the motor vehicle 2 is used. Determining “off-line” of the second variant of the first embodiment and determining “on-line” can be combined.
The second embodiment corresponds to a statistical estimation based on an analysis of a set of acceleration and brake phases over time.
In said second embodiment, the method further comprises a determining step E11 preceding the estimating step E2. The determining step E11 is implemented by a determining module 51. Said determining step E11 consists in determining an estimation of the transfer function
Figure pctxmlib-appb-M000119
 of the suspension system 4.
In said second embodiment, the method further comprises a determining step E12 preceding the estimating step E2. The determining step E12 consists in determining an estimation of the characteristic parameter
Figure pctxmlib-appb-M000120
.
The determining step E12 is implemented by a determining module 52. It comprises the following sub-steps:
  • a measuring sub-step E121;
  • a filtering sub-step E122;
  • an aggregating sub-step E123;
  • an aggregating sub-step E124;
  • a comparison sub-step E125;
  • a comparison sub-step E126;
  • an estimating sub-step E127;
  • an estimating sub-step E128.
The measuring sub-step E121 is implemented by a gyrometer 7 on board the motor vehicle 2. The measuring sub-step E121 consists in measuring over time angle variations
Figure pctxmlib-appb-M000121
 of the motor vehicle 2.
On flat terrain, the angle variations
Figure pctxmlib-appb-M000122
 measured by the gyrometer 7 correspond to pitch variations.
The filtering sub-step E122 is implemented by a filtering sub-module 8. consisting in filtering the angle variations measured in the measuring sub-step E121.
The aggregating sub-step E123 is implemented by an aggregating sub-module 9. The aggregating sub-step E123 consists in aggregating the angle variations filtered in the filtering sub-step E122 when the motor vehicle 2 is in an acceleration phase as a function of an estimation of a relevance of the filtered angle variations. The relevance can be a predetermined relevance.
The aggregating sub-step E124 is implemented by an aggregating sub-module 10. The aggregating sub-step E124 consists in aggregating the angle of variations filtered in the filtered sub-step E122 when the motor vehicle 2 is in a brake phase as a function of an estimation of the relevance of the filtered angle variation. Likewise, the relevance can be a predetermined relevance.
The comparison sub-step E125 is implemented by a comparison sub-module 11. The comparison sub-step E125 consists in comparing the aggregated angle variations when the motor vehicle 2 is in an acceleration phase to the longitudinal acceleration Γ of the motor vehicle 2 measured in the measuring step E1 when the motor vehicle 2 is in the acceleration phase. In other words, the comparison sub-step E125 consists in comparing the aggregated angle variations when the motor vehicle 2 is in an acceleration phase to the variations of the total pitch angle calculated from the longitudinal acceleration Γ of the motor vehicle 2 measured in the measuring step E1 when the motor vehicle 2 is in the acceleration phase.
The comparison sub-step E126 is implemented by a comparison sub-module 12. The comparison sub-step E126 consists in comparing the aggregated angle variations when the motor vehicle 2 is in the brake phase to the longitudinal acceleration Γ of the motor vehicle 2 measured in the measuring step E1 when the motor vehicle 2 is in the brake phase. In other words, the comparison sub-step E126 consists in comparing the aggregated angle variations when the motor vehicle 2 is in a brake phase to the variations of the total pitch angle calculated from the longitudinal acceleration Γ of the motor vehicle 2 measured in the measuring step E1 when the motor vehicle 2 is in the brake phase.
The estimating sub-step E127 is implemented by an estimating sub-module 13. The estimating sub-step E127 consists in estimating, from the comparison implemented in the comparison sub-step E126 a first characteristic parameter
Figure pctxmlib-appb-M000123
 corresponding to the characteristic parameter
Figure pctxmlib-appb-M000124
 when the motor vehicle 2 is in an acceleration phase. A quality of the estimation of the first characteristic parameter
Figure pctxmlib-appb-M000125
 can be also provided in the estimating sub-step E127.
The estimating sub-step E128 is implemented by an estimating sub-module 14. The estimating sub-step E128 consists in estimating from the comparison implemented in the comparison sub-step E126 a second characteristic parameter
Figure pctxmlib-appb-M000126
 corresponding to the characteristic parameter
Figure pctxmlib-appb-M000127
 when the motor vehicle 2 is in a braking phase. A quality of the estimation of the second characteristic parameter
Figure pctxmlib-appb-M000128
 can be also provided in the estimating sub-step E128.
On figure 5, a graph shows the variation angle as a function of time T (in s). Curve C3 (in full line) is obtained by the angle variations measured by the gyrometer 7 in an acceleration phase. Curve C4 (in dotted line) is obtained by the variations of the total pitch angle calculated from the longitudinal acceleration Γ. The first characteristic parameter
Figure pctxmlib-appb-M000129
 is 3.71.
On figure 6, a graph shows the variation angle as a function of time T (in s). Curve C5 (full line) is obtained by the angle variations measured by the gyrometer 7 in a brake phase. Curve C6 (dotted line) is obtained by the variations of the total pitch angle calculated from the longitudinal acceleration Γ. The second characteristic parameter
Figure pctxmlib-appb-M000130
 is 2.31.
The “on-line determination” allows wear of the suspension system 4 to be taken into account.
The first predetermined characteristic parameter
Figure pctxmlib-appb-M000131
 and the second predetermined characteristic parameter
Figure pctxmlib-appb-M000132
 vary as a function of the loading since the motor vehicle 2 is heavier and closer to the road 3. The variation is taken into account.
The disclosure further deals with a system 1 for estimating a total pitch angle
Figure pctxmlib-appb-M000133
 of a motor vehicle 2 while the motor vehicle 2 is running along a path on a road 3.
The system 1, schematically shown on , comprises at least:
  • an accelerometer 5 on board the motor vehicle 2 configured to measure over time at least the longitudinal acceleration
    Figure pctxmlib-appb-M000134
     of the motor vehicle 2;
  • an estimating module 6 configured to estimate the dynamic pitch angle
    Figure pctxmlib-appb-M000135
     of the motor vehicle 2 thanks to the longitudinal acceleration
    Figure pctxmlib-appb-M000136
     measured by the accelerometer 5 from the following equation
    Figure pctxmlib-appb-M000137
    ;
  • an estimating module 62 configured to estimate the total pitch angle
    Figure pctxmlib-appb-M000138
    , the total pitch angle
    Figure pctxmlib-appb-M000139
     being equal to the sum of the dynamic pitch angle
    Figure pctxmlib-appb-M000140
     estimated by the estimating module 6 and a static pitch angle
    Figure pctxmlib-appb-M000141
     corresponding to a pitch angle when the motor vehicle 2 is stationary;
  • a transmitting module 63 configured to transmit a signal representative of the estimated total pitch angle
    Figure pctxmlib-appb-M000142
     to the user device HL.
The system 1 may further comprise comprises a determining module 51, configured to determine an estimation of the transfer function
Figure pctxmlib-appb-M000143
 of the suspension system.
The system 1 may further comprise a determining module 52 configured to determine an estimation of the characteristic parameter
Figure pctxmlib-appb-M000144
.
The determining module 52 may comprise:
  • a gyrometer 7 on board the motor vehicle 2 configured to measure over time angle variations of the motor vehicle 2;
  • a filtering sub-module 8 configured to filter the angle variations measured in by the gyrometer 7;
  • an aggregating sub-module 9 configured to aggregate the angle variations filtered by the filtering sub-module 8 when the motor vehicle 2 is in an acceleration phase as a function of an estimation of a relevance of the filtered angle variations;
  • an aggregating sub-module 10 configured to aggregate the angle of variations filtered by the filtered sub-module 8 when the motor vehicle 2 is in a brake phase as a function of an estimation of the relevance of the filtered angle variation;
  • a comparison sub-module 11 configured to compare the aggregated angle variations when the motor vehicle 2 is in an acceleration phase to the longitudinal acceleration
    Figure pctxmlib-appb-M000145
     of the motor vehicle 2 measured by the accelerometer 5 when the motor vehicle 2 is in the acceleration phase;
  • a comparison sub-module 12 configured to compare the aggregated angle variations when the motor vehicle 2 is in the brake phase to the longitudinal acceleration
    Figure pctxmlib-appb-M000146
     of the motor vehicle 2 measured by the accelerometer 5 when the motor vehicle 2 is in the brake phase;
  • an estimating sub-module 13 configured to estimate, from the comparison implemented by the comparison sub-module 11, a first characteristic parameter
    Figure pctxmlib-appb-M000147
     corresponding to the characteristic parameter
    Figure pctxmlib-appb-M000148
     when the motor vehicle is in an acceleration phase;
  • an estimating sub-module 14 configured to estimate from the comparison implemented by the second comparison sub-module 12, a second characteristic parameter
    Figure pctxmlib-appb-M000149
     corresponding to the characteristic parameter
    Figure pctxmlib-appb-M000150
     when the motor vehicle 2 is in a braking phase.
The quality of the estimation of the first characteristic parameter
Figure pctxmlib-appb-M000151
 can be also provided by the estimating sub-module 13. The quality of the estimation of the second characteristic parameter
Figure pctxmlib-appb-M000152
 can be also provided by the estimating sub-module 14.
The estimating method and system can be specific in that:
  • they use a transfer function
    Figure pctxmlib-appb-M000153
     more complex than a 2nd order (for example the ratio of two 2nd order expressions allowing to take into account the coupling between the vertical movement and the rotation, to include a phase advance to reduce the delay taken by the mechanical system of pitch correction;
  • they use a method for identifying the transfer function
    Figure pctxmlib-appb-M000154
     and the characteristic parameter
    Figure pctxmlib-appb-M000155
     for each type of vehicle:
    • an off-line method allowing the identification for any type of vehicle and especially of all the variants compared to a basic model,
    • an on-line method allowing to take into account the loading of the vehicle as well as the aging and/or the change of the suspensions;
  • they use aggregation of all the effects: anti-dive of the motor vehicle, anti-squat of the motor vehicle, slope of the road, reverse transfer of the pitch correction system, taking into account the aging of the suspensions;
  • they allow an autonomy in relation to information coming from the motor vehicle. And when using vehicle data, it allows robustness in degraded mode;
  • they provide an improvement in the calculation of the static pitch because it eliminates the disturbance caused by the dynamic pitch.

Claims (18)

  1. Method for estimating a total pitch angle of a motor vehicle (2) while the motor vehicle (2) is running along a path on a road (3), said total pitch angle (
    Figure pctxmlib-appb-M000156
    ) corresponding to an angle between a longitudinal reference axis (A1) of a chassis (21) of the motor vehicle (2) and a longitudinal reference axis (A2) of the road (3) on which the motor vehicle (2) is intended to run, the motor vehicle (2) having a suspensions system (4),
    characterised in that it comprises at least the following steps:
    • a first measuring step (E1), implemented by an accelerometer (5) on board the motor vehicle (2), consisting in measuring over time at least a longitudinal acceleration (
      Figure pctxmlib-appb-M000157
      ) of the motor vehicle (2);
    • a first estimating step (E2), implemented by a first estimating module (6), consisting in estimating a dynamic pitch angle (
      Figure pctxmlib-appb-M000158
      ) of the motor vehicle (2) thanks to the longitudinal acceleration measured in the measuring step (E1) from the following equation:
    Figure pctxmlib-appb-M000159
    , wherein:
    Figure pctxmlib-appb-M000160
     corresponds to the dynamic pitch angle of the motor vehicle,
    Figure pctxmlib-appb-M000161
     corresponds to the longitudinal acceleration of the motor vehicle (2) measured by the accelerometer (5),
    Figure pctxmlib-appb-M000162
     corresponds to a characteristic parameter of the suspension system (4) of the motor vehicle (2),
    Figure pctxmlib-appb-M000163
     corresponds to a transfer function of the suspension system (4);
    • a second estimating step (E3), implemented by a second estimating module (62), consisting in estimating the total pitch angle (
      Figure pctxmlib-appb-M000164
      ), the total pitch angle (
      Figure pctxmlib-appb-M000165
      ) being equal to the sum of the dynamic pitch angle (
      Figure pctxmlib-appb-M000166
      ) estimated in the first estimating step (E1) and a static pitch angle (
      Figure pctxmlib-appb-M000167
      ) corresponding to a pitch angle when the motor vehicle (2) is stationary;
    • a transmitting step (E4), implemented by a transmitting module (63), consisting in transmitting a signal representative of the estimated total pitch angle (
      Figure pctxmlib-appb-M000168
      ) to a user device (HL) of the motor vehicle (2).
  2. Method according to claim 1,
    characterised in that it comprises a third estimating step (E21), implemented by a third estimating module (61), consisting in estimating the static pitch angle (
    Figure pctxmlib-appb-M000169
    ) when the motor vehicle (2) is stationary and when the motor vehicle (2) is running along.
  3. Method according to any of claims 1 or 2,
    characterised in that the transfer function (
    Figure pctxmlib-appb-M000170
    ) of the suspension system is predetermined.
  4. Method according to any of claims 1 or 2,
    characterised in that it further comprises a first determining step (E11) preceding the first estimating step (E2), the first determining step (E11), implemented by a first determining module (51), consisting in determining an estimation of the transfer function (
    Figure pctxmlib-appb-M000171
    ) of the suspension system.
  5. Method according to any of claims 1 to 4,
    characterised in that the characteristic parameter (
    Figure pctxmlib-appb-M000172
    ) is equal to a first predetermined characteristic parameter (
    Figure pctxmlib-appb-M000173
    ) when the motor vehicle is in an acceleration phase, the characteristic parameter (
    Figure pctxmlib-appb-M000174
    ) is equal to a second predetermined characteristic parameter (
    Figure pctxmlib-appb-M000175
    ) when the motor vehicle is in a braking phase.
  6. Method according to any of claims 1 to 4,
    characterised in that it further comprises a second determining step (E12) preceding the first estimating step (E2), the second determining step (E12) consisting in determining an estimation of the characteristic parameter (
    Figure pctxmlib-appb-M000176
    ),
    the second determining step (E12), implemented by a second determining module (52), comprising the following sub-steps:
    • a measuring sub-step (E121), implemented by a gyrometer (7) on board the motor vehicle (2), consisting in measuring over time angle variations of the motor vehicle (2);
    • a filtering sub-step (E122), implemented by a filtering sub-module (8), consisting in filtering the angle variations measured in the measuring sub-step (E121);
    • a first aggregating sub-step (E123), implemented by a first aggregating sub-module (9), consisting in aggregating the angle variations filtered in the filtering sub-step (E122) when the motor vehicle (2) is in an acceleration phase as a function of an estimation of a relevance of the filtered angle variations;
    • a second aggregating sub-step (E124), implemented by a second aggregating sub-module (10), consisting in aggregating the angle of variations filtered in the filtered sub-step (E122) when the motor vehicle (2) is in a brake phase as a function of an estimation of the relevance of the filtered angle variation;
    • a first comparison sub-step (E125), implemented by a first comparison sub-module (11), consisting in comparing the aggregated angle variations when the motor vehicle (2) is in an acceleration phase to the longitudinal acceleration (
      Figure pctxmlib-appb-M000177
      ) of the motor vehicle (2) measured in the first measuring step (E1) when the motor vehicle (2) is in the acceleration phase;
    • a second comparison sub-step (E126), implemented by a second comparison sub-module (12), consisting in comparing the aggregated angle variations when the motor vehicle (2) is in the brake phase to the longitudinal acceleration (
      Figure pctxmlib-appb-M000178
      ) of the motor vehicle (2) measured in the first measuring step (E1) when the motor vehicle (2) is in the brake phase;
    • a first estimating sub-step (E127), implemented by a first estimating sub-module (13), consisting in estimating, from the comparison implemented in the first comparison sub-step (E125), a first characteristic parameter (
      Figure pctxmlib-appb-M000179
      ) corresponding to the characteristic parameter (
      Figure pctxmlib-appb-M000180
      ) when the motor vehicle is in an acceleration phase;
    • a second estimating sub-step (E128), implemented by a second estimating sub-module (14), consisting in estimating from the comparison implemented in the second comparison sub-step (E126), a second characteristic parameter (
      Figure pctxmlib-appb-M000181
      ) corresponding to the characteristic parameter (
      Figure pctxmlib-appb-M000182
      ) when the motor vehicle (2) is in a braking phase.
  7. Method according to any of claims 4 or 6,
    characterised in that the first determining step (E11) and/or the second determining step (E12) are implemented while the motor vehicle (2) is running along.
  8. Method according to any of claims 1 to 7,
    characterised in that the signal representative of the estimated total pitch angle (
    Figure pctxmlib-appb-M000183
    ) corresponds to a command related to the estimated total pitch angle (
    Figure pctxmlib-appb-M000184
    ) intended to command at least one actuator of the user device (HL) in order to change the orientation of the headlamp according to the estimated total pitch angle (
    Figure pctxmlib-appb-M000185
    ).
  9. Method according to claim 8,
    characterised in that the command compensates known defaults of the user device (HL).
  10. System for estimating a total pitch angle of a motor vehicle (2) while the motor vehicle (2) is running along a path on a road (3), said total pitch angle (
    Figure pctxmlib-appb-M000186
    ) corresponding to an angle between a longitudinal reference axis of a chassis (21) of the motor vehicle (2) and a longitudinal reference axis of the road (3) on which the motor vehicle (2) is intended to run, the motor vehicle (2) having a suspensions system (4),
    characterised in that it comprises at least:
    • an accelerometer (5) on board the motor vehicle (2) configured to measure over time at least a longitudinal acceleration (
      Figure pctxmlib-appb-M000187
      ) of the motor vehicle (2);
    • a first estimating module (6) configured to estimate a dynamic pitch angle (
      Figure pctxmlib-appb-M000188
      ) of the motor vehicle (2) thanks to the longitudinal acceleration (
      Figure pctxmlib-appb-M000189
      ) measured by the accelerometer (5) from the following equation:
    Figure pctxmlib-appb-M000190
    , wherein:
    Figure pctxmlib-appb-M000191
     corresponds to the pitch angle of the motor vehicle,
    Figure pctxmlib-appb-M000192
     corresponds to the longitudinal acceleration of the motor vehicle (2) measured by the accelerometer (5),
    Figure pctxmlib-appb-M000193
     corresponds to a characteristic parameter of the suspension system (4) of the motor vehicle (2),
    Figure pctxmlib-appb-M000194
     corresponds to a transfer function of the suspension system (4);
    • a second estimating module (62) configured to estimate the total pitch angle (
      Figure pctxmlib-appb-M000195
      ), the total pitch angle (
      Figure pctxmlib-appb-M000196
      ) being equal to the sum of the dynamic pitch angle (
      Figure pctxmlib-appb-M000197
      ) estimated by the first estimating module (6) and a static pitch angle (
      Figure pctxmlib-appb-M000198
      ) corresponding to a pitch angle when the motor vehicle (2) is stationary;
    • a transmitting module (63) configured to transmit a signal representative of the estimated total pitch angle (
      Figure pctxmlib-appb-M000199
      ) to a user device (HL).
  11. System according to claim 10,
    it comprises a third estimating module (61) configured to estimate the static pitch angle (
    Figure pctxmlib-appb-M000200
    ) when the motor vehicle (2) is stationary and when the motor vehicle (2) is running along.
  12. System according to claim 10 or 11,
    characterised in that the transfer function (
    Figure pctxmlib-appb-M000201
    ) of the suspension system (4) is predetermined.
  13. System according to any of claims 10 or 11,
    characterised in that it further comprises a first determining module (51), configured to determine an estimation of the transfer function (
    Figure pctxmlib-appb-M000202
    ) of the suspension system.
  14. System according to any of claims 10 to 13,
    characterised in that the characteristic parameter (
    Figure pctxmlib-appb-M000203
    ) is equal to a first predetermined characteristic parameter (
    Figure pctxmlib-appb-M000204
    ) when the motor vehicle (2) is in an acceleration phase, the characteristic parameter (
    Figure pctxmlib-appb-M000205
    ) is equal to a second predetermined characteristic parameter (
    Figure pctxmlib-appb-M000206
    ) when the motor vehicle (2) is in a braking phase.
  15. System according to any of claims 10 to 13,
    characterised in that it further comprises a second determining module (52) configured to determine an estimation of the characteristic parameter (
    Figure pctxmlib-appb-M000207
    ),
    the second determining module (52) comprising:
    • a gyrometer (7) on board the motor vehicle (2) configured to measure over time angle variations of the motor vehicle (2);
    • a filtering sub-module (8) configured to filter the angle variations measured in by the gyrometer (7);
    • a first aggregating sub-module (9) configured to aggregate the angle variations filtered by the filtering sub-module (8) when the motor vehicle (2) is in an acceleration phase as a function of an estimation of a relevance of the filtered angle variations;
    • a second aggregating sub-module (10) configured to aggregate the angle of variations filtered by the filtered sub-module (8) when the motor vehicle (2) is in a brake phase as a function of an estimation of the relevance of the filtered angle variation;
    • a first comparison sub-module (11) configured to compare the aggregated angle variations when the motor vehicle (2) is in an acceleration phase to the longitudinal acceleration (
      Figure pctxmlib-appb-M000208
      ) of the motor vehicle (2) measured by the accelerometer (5) when the motor vehicle (2) is in the acceleration phase;
    • a second comparison sub-module (12) configured to compare the aggregated angle variations when the motor vehicle (2) is in the brake phase to the longitudinal acceleration (
      Figure pctxmlib-appb-M000209
      ) of the motor vehicle (2) measured by the accelerometer (5) when the motor vehicle (2) is in the brake phase;
    • a first estimating sub-module (13) configured to estimate, from the comparison implemented by the first comparison sub-module (11), a first characteristic parameter (
      Figure pctxmlib-appb-M000210
      ) corresponding to the characteristic parameter (
      Figure pctxmlib-appb-M000211
      ) when the motor vehicle is in an acceleration phase;
    • a second estimating sub-module (14) configured to estimate from the comparison implemented by the second comparison sub-module (12), a second characteristic parameter (
      Figure pctxmlib-appb-M000212
      ) corresponding to the characteristic parameter (
      Figure pctxmlib-appb-M000213
      ) when the motor vehicle (2) is in a braking phase.
  16. System according to claim 13,
    characterised in that the first determining module (51) and/or the second determining module (52) are configured to be implemented while the motor vehicle 2 is running along.
  17. System according to any of claims 10 to 16,
    characterised in that the signal representative of the estimated total pitch angle (
    Figure pctxmlib-appb-M000214
    ) corresponds to a command related to the estimated total pitch angle (
    Figure pctxmlib-appb-M000215
    ) intended to command at least one actuator of the user device (HL) in order to change the orientation of the headlamp according to the estimated total pitch angle (
    Figure pctxmlib-appb-M000216
    ).
  18. Method according to claim 17,
    characterised in that the command compensates known defaults of the user device (HL).
PCT/EP2022/082985 2021-11-23 2022-11-23 Method and system for estimating a total pitch angle of a motor vehicle. WO2023094452A1 (en)

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Citations (5)

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US20070067085A1 (en) * 2005-09-19 2007-03-22 Ford Global Technologies Llc Integrated vehicle control system using dynamically determined vehicle conditions
US20100094495A1 (en) * 2007-03-05 2010-04-15 Yokohama National University Pitching control device of motor vehicle and control method
JP4726277B2 (en) * 2000-05-31 2011-07-20 株式会社デンソー Automatic headlamp optical axis adjustment device for vehicles
EP2708417A2 (en) * 2012-09-13 2014-03-19 Valeo Schalter und Sensoren GmbH Vehicle headlight with emission direction pivotable in vertical direction
US20150291082A1 (en) * 2014-04-14 2015-10-15 Koito Manufacturing Co., Ltd. Vehicle lamp control apparatus

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4726277B2 (en) * 2000-05-31 2011-07-20 株式会社デンソー Automatic headlamp optical axis adjustment device for vehicles
US20070067085A1 (en) * 2005-09-19 2007-03-22 Ford Global Technologies Llc Integrated vehicle control system using dynamically determined vehicle conditions
US20100094495A1 (en) * 2007-03-05 2010-04-15 Yokohama National University Pitching control device of motor vehicle and control method
EP2708417A2 (en) * 2012-09-13 2014-03-19 Valeo Schalter und Sensoren GmbH Vehicle headlight with emission direction pivotable in vertical direction
US20150291082A1 (en) * 2014-04-14 2015-10-15 Koito Manufacturing Co., Ltd. Vehicle lamp control apparatus

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