Method for mitigating disturbances in the measurement of a vehicle's tilt angle

Abstract

The invention relates to a method for mitigating disturbances in the measurement of a lateral tilt angle of a motorized two-wheeled vehicle (1) comprising an electronic control unit (11) configured to calculate a lateral tilt angle of the vehicle from the measurements of a tilt sensor (111), said method comprising the steps of: receiving (E1) the value of the speed of the vehicle (1) measured by the speed measurement module (13), receiving (E2) the number of rotations per minute of the motor (10), calculating (E3) the ratio between the received speed value and the received number of rotations per minute, comparing (E7) the ratio between the received speed value and the number of rotations per minute with an attenuation interval, if the ratio is outside the attenuation interval, calculating the tilt angle without attenuation, if the ratio is within the attenuation interval, calculating (E7) the tilt angle with attenuation.Figure for the abridged version: Fig 4.

Description

Title of the invention: Method for mitigating disturbances in the measurement of a vehicle's tilt angle. Technical field

[0001] The present invention relates to the field of motorized two-wheeled vehicles and more particularly concerns the measurement of the lateral tilt angle of a motorized two-wheeled vehicle. Previous technique

[0002] To improve driver safety, many motorized two-wheeled vehicles are now equipped with systems that can act directly on the operation of the vehicle, without the intervention of the driver, as soon as a critical situation is detected.

[0003] It is well known that manufacturers of motorized two-wheeled vehicles include tilt sensors in these vehicles that measure, among other things, the lateral tilt of the vehicle. These sensors are configured to have a maximum tilt threshold above which the vehicle is considered to be falling, triggering the engine to shut off and thus ensuring the safety of the rider.

[0004] For example, if this threshold is 60° with respect to a vertical direction defined by Earth's gravity, and the effective angle of inclination of the vehicle is beyond 60°, the vehicle is considered to be falling and the engine is stopped.

[0005] This device also makes it possible to prevent the engine from starting if the vehicle is inclined beyond this threshold when the user starts it.

[0006] First-generation mechanical tilt sensors are attached to the vehicle chassis. These sensors contain weights (for example, balls) that move according to the vehicle's tilt and close electrical contacts at a given angle. The inertia of these weights determines the sensor's sensitivity to the vehicle's tilt and, consequently, the accuracy of the angle measurement.

[0007] However, these sensors are bulky and impose significant mounting constraints on the vehicle chassis. For these reasons, a new generation of sensors is used, consisting of an electronic control unit containing a MEMS (Micro Electro Mechanical System) type accelerometer. This type of sensor can be mounted directly on the engine, on the intake manifold for example, or mounted near the engine.

[0008] However, due to the proximity of the sensor to the engine, vibrations generated by the engine can affect the sensor and create disturbances in the tilt angle measurement. The risk is that these disturbances will then cause an artificial exceedance of the maximum tilt threshold for a sufficient duration for the electronic control unit to interpret it as a fall, thus triggering the engine shutdown function during normal vehicle operation.

[0009] This problem is exacerbated by the sampling of the tilt angle measurements. Indeed, the disturbances related to the operation of the motor are periodic. Consequently, if the sampling frequency is not matched to the frequency of the disturbances (according to Shannon's theorem), the reconstructed signal may have a period longer than that of the mechanical vibrations of the motor. This phenomenon is known as aliasing and can therefore result in an artificial exceedance of the maximum tilt threshold for a longer period, thus increasing the risk that the electronic control unit will trigger the motor to shut down.

[0010] One solution to reduce the aliasing problem is to increase the sampling frequency for the tilt angle measurement in order to capture the actual period of the disturbances. However, this solution is energy-intensive and consumes computing power, which can then become saturated, limiting its ability to perform and store more measurements. Furthermore, it does not prevent the engine vibrations from artificially exceeding the tilt threshold during the tilt angle measurement, even without aliasing.

[0011] There is therefore a need for a simple and effective solution to remedy at least some of these drawbacks. Description of the invention

[0012] To this end, the invention first relates to a method for mitigating disturbances in the measurement of the lateral tilt angle of a motorized two-wheeled vehicle, said vehicle comprising an engine connected to a mechanical gearbox, an electronic control unit, and a speed measurement module, said electronic control unit comprising a tilt sensor and a memory area comprising at least one predetermined attenuation interval, said electronic control unit being configured to calculate the lateral tilt angle of the vehicle from the tilt sensor measurements, to receive a value for the vehicle's speed measured by the speed measurement module, and to receive the engine's revolutions per minute, said method comprising the steps of:

[0013] - reception, by the electronic control unit, of the vehicle speed value measured by the speed measurement module,

[0014] - reception, by the electronic control unit, of the number of rotations per minute performed by the engine,

[0015] - calculation, by the electronic control unit, of the ratio between the speed value received and the number of rotations per minute received,

[0016] - comparison, by the electronic control unit, of the ratio between the value of the received velocity and the number of rotations per minute with at least one attenuation interval,

[0017] - if the ratio between the value of the received speed and the number of rotations per minute is outside the attenuation range, calculation, by the electronic control unit, of the tilt angle without attenuation,

[0018] - if the ratio between the value of the received speed and the number of rotations per minute is included in the attenuation range, calculation, by the electronic control unit, of the angle of inclination with attenuation.

[0019] The method according to the invention thus makes it possible to mitigate the effect of engine vibrations on the determination of the vehicle's lateral tilt angle. When these vibrations are considered likely to cause disturbances in the angle measurement that could result in an overshoot for an excessive duration, which could then trigger the vehicle's stop function, the electronic control unit attenuates certain components of the tilt sensor measurements that would most impact the tilt angle measurement. Thus, the tilt angle remains representative of the vehicle's physical tilt, but the vibrations are less likely to cause oscillations in the calculated tilt angle that could otherwise exceed the tilt threshold.When the ratio between the received speed value and the number of revolutions per minute falls within the attenuation range, the vehicle's speed is consistent with the engine speed and therefore is unlikely to be falling. Consequently, the attenuation process prevents a false fall detection. Conversely, if the ratio between the received speed value and the number of revolutions per minute is outside this range, there is a decoherence that may indicate a problem, and it is therefore safer not to attenuate the signals so that the engine shutdown command can be sent as quickly as possible.

[0020] Preferably, the engine is connected to a mechanical gearbox, and the step of receiving the engine's revolutions per minute from the electronic control unit is followed by a step of determining the selected gear ratio of the gearbox. The selected gear ratio can be determined directly by sending signals from the gearbox to the control unit. electronic, or by calculating the ratio between the measured speed and the number of rotations per minute in the motor, and can serve as redundancy in verifying the conditions for applying the method according to the invention.

[0021] Advantageously, if the electronic control unit receives information from the gearbox indicating that no gear is engaged, the electronic control unit calculates the tilt angle without attenuation, without performing the step of calculating the ratio between the received speed value and the received engaged gear. In this case, engine vibrations are reduced and therefore do not need to be attenuated. The engine may be running, for example, if the vehicle is stationary and about to start, and the measurement of the vehicle's tilt angle is relevant.

[0022] In a preferred embodiment, the speed measuring module stores a reference speed value and sends this reference speed value to the electronic control unit in the event of a failure of the speed measuring module. The tilt angle measurement and the measurement attenuation process can thus function even in the event of a failure of the speed measuring module.

[0023] In one embodiment of the invention, the tilt sensor is configured to determine the projection of Earth's gravity onto three axes. The electronic control unit is configured to calculate the tilt angle from the three projections determined by the tilt sensor, and the memory area includes at least one attenuation coefficient. The step of calculating the tilt angle with attenuation corresponds to the electronic control unit multiplying at least one projection determined by the tilt sensor by at least one attenuation coefficient. The attenuation can be applied to one of the projections measured by the tilt sensor; thus, if one of the projections is determined not to have a significant influence on the calculation of the tilt angle, the electronic control unit does not need to attenuate that projection in the calculation.The projections can be considered as not having a first-order influence, for example, by performing a self-test of the electronic control unit when it applies modifications to the projection that do not change or only slightly change the calculated angle of inclination.

[0024] Advantageously, in this embodiment, the memory area comprises at least three attenuation coefficients, each corresponding to a projection axis, and wherein the step of calculating the tilt angle with attenuation corresponds to multiplying, by the electronic control unit, each of the three projections determined by the tilt sensor by the corresponding attenuation coefficient. The attenuation can therefore be applied appropriately to each of the three projections measured by the tilt sensor.

[0025] Advantageously, the memory area includes at least one attenuation coefficient corresponding to each of the vehicle's gearbox ratios, and the step of calculating the tilt angle with attenuation corresponds to the electronic control unit multiplying at least one projection determined by the tilt sensor by the attenuation coefficient corresponding to the received gear ratio. Different attenuation is thus performed by the electronic control unit depending on the gear engaged in the vehicle's gearbox.

[0026] Preferably in this embodiment, the memory area comprises, for each of the vehicle's gearbox ratios, three attenuation coefficients, each corresponding to a projection axis. The step of calculating the tilt angle with attenuation involves multiplying, by the electronic control unit, each of the projections determined by the tilt sensor by the attenuation coefficient corresponding to the projection axis and the received gear ratio. The attenuation is thus adapted as closely as possible to the vehicle's operation.

[0027] According to another aspect, the invention also relates to an electronic control unit for a motorized two-wheeled vehicle, said electronic control unit comprising a tilt sensor and a memory area, said memory area comprising at least one attenuation interval, and said electronic control unit being configured to be connected to a speed measurement module and to the mechanical gearbox of the engine of said vehicle, said electronic control unit being further configured to:

[0028] - receive a value of the vehicle speed measured by the measurement module speed,

[0029] - receive the gear ratio engaged in the gearbox,

[0030] - calculate the ratio between the received speed value and the engaged speed ratio received,

[0031] - compare the ratio between the received velocity value and the velocity ratio committed with the first threshold,

[0032] - calculate the angle of inclination of the vehicle without attenuation,

[0033] - calculate the angle of inclination of the vehicle with attenuation.

[0034] According to another aspect, the invention also relates to a motorized two-wheeled vehicle, comprising an engine connected to a gearbox, a speed measurement module and an electronic control unit as shown. Brief description of the drawings

[0035] Other features and advantages of the invention will become apparent from the following description. This description is purely illustrative and should be read in conjunction with the accompanying drawings, in which:

[0036] [Fig-1] Fig. 1 schematically illustrates a motorized two-wheeled vehicle in to which the process according to the invention applies.

[0037] [Fig.2] Fig.2 schematically illustrates an electronic control unit implementing the process.

[0038] [Fig.3] The [Fig.3] schematically illustrates the lateral inclination of the vehicle relative to an inclination threshold triggering the engine stop function.

[0039] [Fig.4] Fig.4 schematically illustrates the process according to the invention. Description of the implementation methods

[0040] The method according to the invention is applicable to a motorized two-wheeled vehicle.

[0041] Vehicle 1

[0042] As shown in [Fig.1], the vehicle 1 comprises an engine 10, an electronic control unit 11, a mechanical gearbox 12, a speed measurement module 13 and a communication link 14.

[0043] Motor 10

[0044] The motor 10 produces the torque necessary to drive the wheels of the vehicle 1 when the vehicle is moving. This torque is supplied by the rotation of a shaft, which rotates at a certain number of revolutions per minute, also called the motor speed.

[0045] The motor 10 is connected to the gearbox 12.

[0046] The engine 10 can be in operation without any gearbox ratio speed 12 is not engaged, for example when starting vehicle 1.

[0047] The gearbox 12 transmits the engine speed to the wheels. Depending on the gear engaged, the proportionality coefficient between the engine speed and the wheel speed is different.

[0048] Electronic control unit 11

[0049] As shown in [Fig.2], the electronic control unit 11 includes a tilt sensor 111 and a memory area 112.

[0050] The tilt sensor 111 is preferably a MEMS type accelerometer, configured to calculate the projection of Earth's gravity onto three axes of a reference frame.

[0051] The electronic control unit 11 is configured to calculate the angle of lateral tilt of the vehicle 1 with respect to the terrestrial vertical Z from the three projections measured by the tilt sensor 111.

[0052] Memory area 112 is configured to store information. In particular, memory area 112 includes an angle 0s, corresponding to a threshold inclination beyond which the electronic control unit 11 considers that the vehicle 1 is falling, as shown in [Fig.3].

[0053] In this [Fig.3], the Z axis corresponds to the terrestrial vertical and the Y axis corresponds to the horizontal direction perpendicular to vehicle 1. The angle of inclination is the angle formed between the Y axis and vehicle 1.

[0054] The memory area 112 also includes at least one attenuation interval corresponding to ratios between the speed of the vehicle 1 and the number of rotations per minute in the motor 10.

[0055] This interval corresponds to the values ​​of this ratio under normal movement conditions of a vehicle 1, in particular when it is not falling.

[0056] Memory area 112 also includes a plurality of stored attenuation coefficients.

[0057] Preferably, the memory area 112 includes a coefficient for each of the three axes of the tilt sensor frame 111 and for each gear ratio of the gearbox 12.

[0058] Thus, for a vehicle 1 having a gearbox 12 comprising for example 5 speed ratios, the memory area 112 comprises 15 coefficients.

[0059] Advantageously, the coefficients stored in memory area 112 are less than or equal to 1.

[0060] The attenuation coefficient(s) can in another embodiment be low-pass filters, which do not attenuate low frequencies (on which the problems of spectral aliasing are less marked) but which attenuate high frequencies.

[0061] The electronic control unit 11 is configured to calculate the tilt angle with attenuation by multiplying at least one projection measured by the tilt sensor 111 by the corresponding coefficient and to calculate the tilt angle from this value.

[0062] The electronic control unit 11 is configured to compare the calculated tilt angle with the tilt threshold 0s.

[0063] The tilt threshold 0s corresponds to the angle from which the electronic control unit 11 considers that the vehicle 1 is falling.

[0064] The electronic control unit 11 is configured to implement a function of stopping the engine 10 of the vehicle 1 if the measured lateral tilt angle is greater than the tilt threshold 0s.

[0065] The electronic control unit 11 is configured to receive, via the communication link 14, the number of rotations per minute of the motor 10.

[0066] The electronic control unit 11 is configured to receive, via the communication link 14, the gear ratio engaged in the gearbox 12 of the engine 10.

[0067] The electronic control unit 11 is also configured to determine the gear ratio engaged in the gearbox 12 of the engine 10 from the calculation of the ratio between the speed of the vehicle 1 and the number of rotations per minute in the engine 10.

[0068] The electronic control unit 11 is configured to receive, via the communication link 14, a value of the speed of the vehicle 1 measured by the speed measurement module 13.

[0069] Gearbox 12

[0070] The gearbox 12 contains several gear ratios which allow the torque produced by the engine 10 to be adapted to the performance desired by the user of the vehicle 1.

[0071] The gearbox 12 is mechanically connected to the motor 10 as shown in [Fig.1].

[0072] The gearbox 12 is configured to send signals to the electronic control unit 11, via the communication link 14, indicating which gear ratio is engaged or whether no gear ratio is engaged.

[0073] Speed ​​measurement module 13

[0074] The speed measurement module 13 is configured to measure the speed of vehicle movement 1.

[0075] The speed measurement module 13 can be of different types, such as for example a rev counter on one of the wheels of the vehicle 1.

[0076] Communication link 14

[0077] The communication link 14 enables communication between the electronic control unit 11 and the motor 10, the gearbox 12 and the speed measurement module 13.

[0078] Preferably, the communication link 14 is a wired communication link, for example of the CAN type.

[0079] Example of implementation

[0080] When the vehicle 1 is moving, the motor 10 is running. The vibrations caused by the operation of the motor 10 propagate to the electronic control unit 11 and are detected by the tilt sensor 111.

[0081] The angle calculated by the electronic control unit 11 from the measurements of the tilt sensor 111 therefore takes these vibrations into account.

[0082] The method according to the invention aims to mitigate the impact of vibrations on the calculation of the angle of inclination in configurations where these are too significant.

[0083] In a first step El of the process, the electronic control unit 11 receives a value of the speed of the vehicle 1 measured by the speed measuring module 13.

[0084] In a second step E2, the electronic control unit 11 receives the number of rotations per minute of the motor 10 and the gear ratio engaged in the gearbox 12. If in this step, the electronic control unit 11 receives that no gear ratio is engaged, the process is stopped.

[0085] Indeed, this scenario indicates that the vehicle 1 is either stationary or moving at a very low speed and without being driven by the motor 10, so there is no need to mitigate the effect of vibrations.

[0086] Steps E1 and E2 can take place indistinguishably one before the other or simultaneously.

[0087] In a step E3, the electronic control unit 11 calculates the ratio between the speed value received from the speed measuring module 13 and the number of rotations per minute of the motor 10.

[0088] In a step E4, the electronic control unit 11 compares the ratio thus calculated to the attenuation interval stored in the memory area 112.

[0089] This interval corresponds to the expected operating points of vehicle 1 under normal conditions. Under these conditions, vehicle 1 is less likely to be tilted beyond the tilt angle threshold 0s, therefore it is relevant to attenuate the signals used to calculate the tilt angle to prevent the electronic control unit 11 from erroneously detecting a fall of vehicle 1 and thus triggering the engine 10 shutdown function.

[0090] If the calculated ratio is outside the attenuation range, it is possible that the vehicle 1 is in an operating position that presents a risk of falling. In order not to distort the detection of a fall, the electronic control unit 11 measures the angle of inclination without attenuation in a step E5*, and the attenuation process is reset from step El.

[0091] If the calculated ratio is within the attenuation range, the electronic control unit 11 detects that the vehicle 1 is unlikely to fall.

[0092] In this case, the electronic control unit 11 selects in a step E5 the triplet of attenuation coefficients corresponding to the engaged speed ratio received during step E2 stored in the memory area 112.

[0093] In a step E6, the electronic control unit 11 multiplies each of the three projections of the acceleration of gravity determined by the tilt sensor 111 by the corresponding attenuation coefficient of the selected triplet.

[0094] In a step E7, the electronic control unit 11 calculates the angle of inclination from the three projections, each multiplied by the corresponding attenuation coefficient.

[0095] The attenuation thus achieved makes it possible to counteract the effects of vibrations from the engine 10 on the measurement of the tilt angle of the vehicle 1 by reducing the calculated tilt angle value when it is likely to oscillate beyond the tilt threshold under conditions where the vehicle 1 is unlikely to fall. The different attenuation coefficients for each speed ratio and each axis of the projection are determined beforehand, for example during pre-production tests of the vehicle 1 for calibration purposes.

[0096] Based on these tests, certain coefficients can be determined to be equal to one, so as not to attenuate the corresponding projection if it is determined that it does not affect the calculation of the physical angle of inclination.

[0097] This process is repeated as long as the motor 10 is running so as to be able to adapt the attenuation according to the gear ratio engaged and the speed of the vehicle 1.

[0098] For example, if vehicle 1 is at some point in a configuration where the angle measurement is attenuated and the user brakes, vehicle 1 may slow down sufficiently so that the area in which the ratio of the measured speed value to the number of revolutions per minute is less than the attenuation interval. In this case, attenuation is no longer desirable, because vehicle 1 is in a potentially hazardous operating state, and the electronic control unit 11 then calculates the tilt angle from the measurements of the tilt sensor 111 without attenuation so as not to distort the detection of a fall.

Claims

1. Demands Method for mitigating disturbances in the measurement of the lateral tilt angle of a motorized two-wheeled vehicle (1), said vehicle (1) comprising an engine (10), an electronic control unit (11), and a speed measurement module (13), said electronic control unit (11) comprising a tilt sensor (111) and a memory area (112) comprising at least one predetermined attenuation interval, said electronic control unit (11) being configured to calculate the lateral tilt angle of the vehicle (1) from the measurements of the tilt sensor (111), to receive a value of the speed of the vehicle (1) measured by the speed measurement module (13), and to receive the number of revolutions per minute of the engine (10), said method comprising the steps of: - reception (El), by the electronic control unit (11), of the vehicle speed value (1) measured by the speed measurement module (13), - reception (E2), by the electronic control unit (11), of the number of rotations per minute performed by the motor (10), - calculation (E3), by the electronic control unit (11), of the ratio between the received speed value and the received number of rotations per minute, - comparison (E4), by the electronic control unit (11), of the ratio between the received speed value and the number of rotations per minute with at least one predetermined attenuation interval, - if the ratio between the received speed value and the number of rotations per minute is outside the attenuation range, the electronic control unit (11) calculates the angle of inclination without attenuation, - if the ratio between the value of the received speed and the engaged speed ratio is within the attenuation range, calculation (E7), by the electronic control unit (11), of the angle of inclination with attenuation.

2. A method according to claim 1, wherein the motor (10) is connected to a mechanical gearbox (12) and wherein the step of receiving, by the electronic control unit (11), the number of rotations per minute performed by the motor (10), is followed by a step of determining the gear ratio engaged in the gearbox (12).

3. A method according to the preceding claim, wherein if the electronic control unit (11) receives from the gearbox (12) that no gear ratio is engaged, the electronic control unit (11) calculates the angle of inclination without attenuation, without performing the step of calculating the ratio between the value of the received speed and the engaged gear ratio received.

4. A method according to any one of the preceding claims, wherein the speed measuring module (13) has a reference speed value in memory and wherein the speed measuring module (13) sends this reference speed value to the electronic control unit (11) in the event of a failure of the speed measuring module (13).

5. A method according to any one of the preceding claims, wherein the tilt sensor (111) is configured to determine the projection of Earth's gravity onto three axes, the electronic control unit (11) is configured to calculate the tilt angle from the three projections determined by the tilt sensor (111), and the memory area (112) includes at least one attenuation coefficient, and wherein the step of calculating the tilt angle with attenuation corresponds to the multiplication by the electronic control unit (11) of at least one projection determined by the tilt sensor (111) with at least one attenuation coefficient.

6. A method according to the preceding claim, wherein the memory area (112) comprises at least three attenuation coefficients, each corresponding to a projection axis, and wherein the step of calculating the tilt angle with attenuation corresponds to the multiplication by the electronic control unit (11) of each of the three projections determined by the tilt sensor (111) with the corresponding attenuation coefficient.

7. A method according to any one of claims 5 or 6, wherein the memory area (112) comprises at least one coefficient attenuation corresponding to each of the gear ratios of the vehicle's gearbox (12) and in which the step of calculating the angle of inclination with attenuation corresponds to the multiplication by the electronic control unit (11) of at least one projection determined by the inclination sensor (111) with the attenuation coefficient corresponding to the received gear ratio.

8. A method according to any one of claims 5 to 7, wherein the memory area (112) comprises, for each of the gear ratios of the vehicle's (11) gearbox (12), three attenuation coefficients, each corresponding to a projection axis, and wherein the step of calculating the tilt angle with attenuation corresponds to the multiplication by the electronic control unit (11) of each of the projections determined by the tilt sensor (111) with the attenuation coefficient corresponding to the projection axis and the received gear ratio.

9. Electronic control unit (11) for a motorized two-wheeled vehicle (1), said electronic control unit (11) comprising an inclination sensor (111) and a memory area (112), said memory area (112) comprising a predetermined attenuation interval, and said electronic control unit (11) being configured to be connected to a speed measurement module (13) and to the motor (10) of said vehicle (1), said electronic control unit (11) being further configured to: - receive a value of the speed of the vehicle (1) measured by the speed measurement module (13), - receive the number of revolutions per minute of the motor (10), - calculate the ratio between the received speed value and the received number of revolutions per minute, - compare the ratio between the received speed value and the number of revolutions per minute with the attenuation interval, - calculate the inclination angle of the vehicle (1) without attenuation,- Calculate the vehicle's angle of inclination (1) with attenuation.

10. Motorized two-wheeled vehicle (1), comprising an engine (10) connected to a gearbox (12), a speed measurement module (13) and an electronic control unit (11) according to the preceding claim.

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