DE102021210387A1 - Method and system for calibrating an accelerometer - Google Patents

Abstract

A method for calibrating an acceleration sensor (10) of a vehicle (100), comprising the steps of: acquiring acceleration measurement data with the acceleration sensor (10) in a calibration position (2) of the vehicle (100), determining a spatial correction angle for attaching to acceleration measurement data which can be detected with the acceleration sensor (10) in an operating position of the vehicle (100), based on the detected acceleration measurement data and as a function of the acceleration of gravity (G) acting on the acceleration sensor (10). In addition, a system (200) for calibrating an acceleration sensor (10) of a vehicle (100).

Description

technical field

The present invention relates to a method and a system for calibrating an acceleration sensor. The present invention also relates to a control device with such a system. The present invention also relates to a vehicle with such a control device.

State of the art

From the DE 10 2019 215 671 A1 it is known to assign measured values detected by an acceleration sensor of a vehicle to a longitudinal acceleration, a vertical acceleration and a lateral acceleration of the vehicle. However, due to the installation position of the acceleration sensor relative to the vehicle axles, it may not be possible to directly assign measured values detected by the acceleration sensor to accelerations relating to vehicle axles.

Presentation of the invention

In one aspect, the present invention relates to a method for calibrating an acceleration sensor of a vehicle. The acceleration sensor can be a two-axis or three-axis acceleration sensor. The acceleration sensor can be set up to detect accelerations related to two or three axes. Axes of the acceleration sensor can be perpendicular to one another or span a right-angled coordinate system. The acceleration sensor can be an inertial measuring unit. The vehicle can be a motor vehicle or a commercial vehicle.

As a step, the method includes acquiring acceleration measurement data with the acceleration sensor in a calibration position of the vehicle. The calibration position can be an operating position of the vehicle, in which the vehicle is located while acceleration measurement data is being recorded with the acceleration sensor. The recorded acceleration measurement data can relate to at least one axis of the acceleration sensor. The acceleration measurement data can have acceleration values which directly or indirectly define an acceleration of the acceleration sensor along at least one axis.

As a further step, the method comprises determining a spatial correction angle for application to accelerometer data. The acceleration measurement data can be recorded with the acceleration sensor in an operating position of the vehicle. The operating position of the vehicle can deviate from or be at a distance from the calibration position of the vehicle. While the vehicle may be at rest in the calibration position, the vehicle may be in motion in the operating position.

The spatial correction angle can have an orientation correction, with which a misalignment of the acceleration sensor in an installed position of the acceleration sensor relative to the vehicle axles of the vehicle can be corrected. The correction angle can therefore be an angle between an axis of the acceleration sensor and a vehicle axis or a relative orientation of the axis of the acceleration sensor to the vehicle axis. The vehicle axis can be, for example, a longitudinal axis, a vertical axis or a transverse axis of the vehicle.

The step of determining the spatial correction angle is performed based on the acquired accelerometer data. The acquired accelerometer data is the accelerometer data acquired at the calibration position. The step of determining the spatial correction angle is also carried out as a function of the gravitational acceleration acting on the acceleration sensor. The acceleration due to gravity acts on the accelerometer data recorded in the calibration position.

An installation position of the acceleration sensor relative to the vehicle can thus be determined with the present invention. A relative position of an axis of the acceleration sensor relative to a vehicle axis can thus be determined. The installation position or the relative position can be attached to the acceleration measurement data of the acceleration sensor in order to correct the acceleration measurement data. Such a correction allows the recorded acceleration measurement data to relate to accelerations which relate to the vehicle or the vehicle axle. In a further step, the method can therefore be used to correct the acceleration measurement data that can be recorded in the operating position in such a way that they relate to the vehicle axles of the vehicle. Furthermore, the installation position of the measuring axes of the acceleration sensor can thus be corrected yaws and calibrated in relation to the vehicle axles.

According to one embodiment of the method, the steps of the method for calibrating an acceleration sensor of a transmission control unit of the vehicle can be carried out. The transmission control unit can control a transmission of the vehicle based on acceleration measurement data recorded with the acceleration sensor. With the method, it is thus advantageously possible to control the transmission of the vehicle based on accelerations that can be detected by the acceleration sensor and relate to a vehicle axis of the vehicle.

According to a further embodiment of the method, the acceleration sensor can be installed in the transmission control unit of the vehicle. The method can also be used to correct an installation position of the transmission control unit and to calibrate the acceleration sensor such that the acceleration measurement data from the acceleration sensor installed in the transmission control unit relate to at least one vehicle axis of the vehicle.

The method may include as a further step applying the spatial correction angle to accelerometer data from the accelerometer. The spatial correction angle can be applied in such a way that the accelerometer data that can be acquired in the operating position of the vehicle corresponds to an acceleration of the vehicle along the vertical axis, the longitudinal axis or the lateral axis of the vehicle.

According to a further embodiment of the method, at least the step of acquiring acceleration measurement data can be carried out when the vehicle is stationary. When the vehicle is stationary, the vehicle may be in the calibration position. When the vehicle is stationary, only the acting gravitational acceleration can act as the acting acceleration on the acceleration sensor. In the calibration position or when the vehicle is stationary, the engine of the vehicle can be switched off in order to avoid vibrations acting on the acceleration sensor.

According to a further embodiment of the method, at least the step of acquiring acceleration measurement data can be carried out in a position of the vehicle in which the vehicle is on a horizontal calibration surface. The position may be the calibration position in which the vehicle may be at rest. A plane spanned by the longitudinal axis and the transverse axis of the vehicle can be arranged parallel to the horizontal calibration surface in the position of the vehicle. The vertical axis of the vehicle can be aligned perpendicular to the horizontal calibration surface in the position of the vehicle. The acceleration due to gravity can also act on the acceleration sensor on the horizontal calibration surface perpendicular to this. The spatial correction angle can thus be determined in a particularly efficient manner.

According to a further embodiment of the method, it can be assumed in the step of determining the correction angle that at least one axis of the acceleration sensor corresponds to at least one axis of the vehicle. The assumption can be made as a function of a partially predetermined installation position of the acceleration sensor.

According to a further embodiment of the method, the step of determining the correction angle can be carried out on the basis of a trigonometric function term, which can have recorded acceleration measurement data and the acting gravitational acceleration. The collected accelerometer data may be the accelerometer data collected at the vehicle's calibration position. The trigonometric function term can form the correction angle. The correction angle can also be derived from or based on the trigonometric function term. The correction factor can thus be determined reliably and robustly.

According to a further embodiment of the method, a calibration status can be displayed to an operator of the vehicle in a further step. For example, the operator can be shown that the acceleration sensor has not yet been calibrated before or during the further steps of the method are carried out.

In a further aspect, the present invention relates to a system for calibrating an acceleration sensor of a vehicle. The system can be located on the vehicle. The system can be set up to carry out the method according to the preceding aspect.

The system has an acceleration sensor for acquiring acceleration measurement data in a calibration position of the vehicle. The system also has an arithmetic unit for determining a spatial correction angle for applying to acceleration measurement data, which is connected to the acceleration sensor in a Operating position of the vehicle can be detected. The computing unit can be set up to determine the spatial correction angle based on the recorded acceleration measurement data and as a function of the acceleration of gravity acting on the acceleration sensor.

In a further aspect, the present invention relates to a control device for controlling a vehicle component. The vehicle component can be a component in a drive train of a vehicle. The control device has a system according to the corresponding preceding aspect. The control unit is set up to control the vehicle component based on acquired acceleration measurement data. According to one embodiment of the control unit, it can be set up to control a transmission of a vehicle.

In a further aspect, the present invention relates to a vehicle which has a control unit according to the corresponding preceding aspect.

Features and embodiments of one aspect of the present invention may form corresponding features and embodiments of another aspect of the present invention.

character list

• 1 FIG. 1 shows a system for calibrating an acceleration sensor and a vehicle with such a system according to a respective embodiment of the invention.
• 2 shows a representation with a correction angle to explain the invention.
• 3 shows a flow chart with steps of a method for calibrating an acceleration sensor according to an embodiment of the invention.

Detailed Description of Embodiments

1 1 shows a system 200 which is set up for calibrating an acceleration sensor 10 of a vehicle 100 . The acceleration sensor 10 is installed in a control device 20 of the vehicle 100 . According to one specific embodiment, control unit 20 is a transmission control unit 22 which is set up to control a transmission 30 of vehicle 100 . The gear 30 is part of an in 1 not shown drive train of the vehicle 100.

Transmission control unit 22 is arranged on transmission 30 . The transmission control unit 22, with the acceleration sensor 10 built into it, has an installation position 12 relative to a vehicle coordinate system 102. The installation position 12 therefore also relates to the installation position 12 of the acceleration sensor 10. The measurement axes of the acceleration sensor 10 do not agree at least in part with the coordinate axes of the vehicle coordinate system 102.

The vehicle 100 is on a roadway 4 which has a horizontal calibration surface 6 . The vehicle 100 is on the horizontal calibration surface 6, with the acceleration due to gravity G acting on the acceleration sensor 10 as the acceleration.

The acceleration sensor 10 is set up to acquire acceleration measurement data in a calibration position 2 of the vehicle 100 in which the vehicle 100 is stationary on the horizontal calibration surface 6 . The system 200 also has a computing unit 210 which is set up to determine a spatial correction angle A which describes a position of the measurement axes of the acceleration sensor 10 relative to the axes of the vehicle coordinate system 102 . The arithmetic unit 210 is also set up to apply the spatial correction angle A to acceleration measurement data which can be detected by the acceleration sensor 10 in an operating position of the vehicle 100, the operating position of the in 1 shown calibration position 2 of the vehicle 100 deviates. The computing unit 210 is also set up to determine the spatial correction angle A based on acceleration measurement data recorded in the calibration position 2 and as a function of the gravitational acceleration G acting on the acceleration sensor 10 .

2 shows the measurement axes of acceleration sensor 10 and acceleration measurement data a′x, a′y and a′z related to them and recorded with acceleration sensor 10 . The measuring axes of the acceleration sensor 10 are rotated by the correction angle A in relation to the axes of the vehicle coordinate system 102 .

definiert, welcher einen Zusammenhang der Beschleunigungsmessdaten a'x mit einem Korrekturfaktor A, auf eine x-Achse des Fahrzeugs 100 bezogene korrigierten Beschleunigungsmessdaten ax und auf eine z-Achse des Fahrzeugs 100 bezogene korrigierten Beschleunigungsmessdaten az beschreibt. Bei der x-Achse des Fahrzeugs handelt es sich um die Längsachse des Fahrzeugs 100 und bei der z-Achse des Fahrzeugs 100 handelt es sich um die Hochachse des Fahrzeugs 100.Acceleration measurement data a′x related to an x-axis of the acceleration sensor 10 and recorded by it are compared with the trigonometric relationship $$\text{a}\text{'}\text{x}=\text{ax cos}\left(\text{A}\right)+\text{az sin}\left(\text{A}\right)$$

defines a relationship between the acceleration measurement data a'x and a correction factor A, corrected acceleration measurement data ax relating to an x-axis of vehicle 100 and corrected acceleration measurement data az relating to a z-axis of vehicle 100 describes. The x-axis of the vehicle is the longitudinal axis of the vehicle 100 and the z-axis of the vehicle 100 is the vertical axis of the vehicle 100.

definiert, welcher einen Zusammenhang der Beschleunigungsmessdaten a'y mit auf eine y-Achse des Fahrzeugs 100 bezogene korrigierten Beschleunigungsmessdaten ay eschreibt. Gemäß einer Ausführungsform wird die Annahme getroffen, dass die beschriebenen Achsen übereinstimmen. Bei der y-Achse des Fahrzeugs 100 handelt es sich um die Querachse des Fahrzeugs 100.Acquired acceleration measurement data a′y related to a y-axis of the acceleration sensor 10 are associated with the trigonometric relationship $$\text{a}\text{'}\text{y}=\text{hey}$$

is defined, which describes a relationship between the acceleration measurement data a′y and corrected acceleration measurement data ay related to a y-axis of the vehicle 100 . According to one embodiment, the assumption is made that the described axes match. The y-axis of the vehicle 100 is the transverse axis of the vehicle 100.

definiert, welcher einen Zusammenhang der Beschleunigungsmessdaten a'z mit dem Korrekturfaktor A, auf die x-Achse des Fahrzeugs 100 bezogene korrigierten Beschleunigungsmessdaten ax und auf die z-Achse des Fahrzeugs 100 bezogene korrigierten Beschleunigungsmessdaten az beschreibt.Acquired acceleration measurement data a′z related to a z-axis of the acceleration sensor 10 are associated with the trigonometric relationship $$\text{a}\text{'}\text{e.g}=-\text{ax sin}\left(\text{A}\right)+\text{az cos}\left(\text{A}\right)$$

is defined, which describes a relationship between the acceleration measurement data a′z with the correction factor A, the corrected acceleration measurement data ax related to the x-axis of the vehicle 100 and the corrected acceleration measurement data az related to the z-axis of the vehicle 100 .

bestimmt, wobei der Korrekturfaktor A basierend auf den auf die x-Achse des Beschleunigungssensors 10 bezogenen Beschleunigungsmessdaten a'x und in Abhängigkeit der auf den Beschleunigungssensor 10 in dem Stillstand einwirkenden Erdbeschleunigung G festgelegt wird.When vehicle 100 is stationary, correction factor A is calculated using the trigonometric function term $$\text{A}={\text{sin}}^{-1}\left(\text{a}\text{'}{\text{x G}}^{-1}\right)$$

is determined, the correction factor A being determined based on the acceleration measurement data a'x related to the x-axis of the acceleration sensor 10 and as a function of the gravitational acceleration G acting on the acceleration sensor 10 when it is stationary.

definiert, welcher die korrigierten Beschleunigungsmessdaten ax basierend auf den auf die x-Achse des Beschleunigungssensors 10 bezogenen erfassten Beschleunigungsmessdaten a'x, der Erdbeschleunigung G und dem bestimmten Korrekturfaktor A definiert.Corrected acceleration measurement data ax related to the x-axis of the vehicle 100 are calculated using the trigonometric relationship $$\text{ax}=\left(\text{a'x}-\text{G sin}\left(\text{A}\right)\right){\left(\text{cos}\left(\text{A}\right)\right)}^{-1}$$

which defines the corrected acceleration measurement data ax based on the acquired acceleration measurement data a'x related to the x-axis of the acceleration sensor 10, the gravitational acceleration G and the determined correction factor A.

definiert, welcher die korrigierten Beschleunigungsmessdaten ay basierend auf den auf die y-Achse des Beschleunigungssensors 10 bezogenen erfassten Beschleunigungsmessdaten a'y definiert.Corrected acceleration measurement data ay related to the y-axis of the vehicle 100 are calculated using the trigonometric relationship $$\text{hey}=\text{a}\text{'}\text{y}$$

which defines the corrected acceleration measurement data ay based on the detected acceleration measurement data a'y related to the y-axis of the acceleration sensor 10 .

definiert, welcher die korrigierten Beschleunigungsmessdaten az basierend auf den auf die z-Achse des Beschleunigungssensors 10 bezogenen erfassten Beschleunigungsmessdaten a'z, der Erdbeschleunigung G und dem bestimmten Korrekturfaktor A definiert.Corrected acceleration measurement data az related to the z-axis of the vehicle 100 are calculated using the trigonometric relationship $$\text{a.s}=\left(\text{a}\text{'}\text{e.g}+\text{G sin}\left(\text{A}\right)\right){\left(\text{cos}\left(\text{A}\right)\right)}^{-1}$$

is defined, which defines the corrected acceleration measurement data az based on the acquired acceleration measurement data a'z related to the z-axis of the acceleration sensor 10, the gravitational acceleration G and the correction factor A determined.

Thus, the acquired accelerometer data a'x, a'y, and a'z based on the correction angle A can be converted into accelerometer data related to the axes of the vehicle coordinate system 102 .

3 FIG. 1 shows a flowchart with method steps for performing a method for calibrating acceleration sensor 10 of vehicle 100 according to one specific embodiment. In a step S1 , acceleration measurement data are recorded using acceleration sensor 10 in calibration position 2 of vehicle 100 . According to one embodiment, the acceleration measurement data a′x related to the x-axis of the acceleration sensor 10 and recorded by it are recorded.

In a further step S2, the spatial correction angle A for application to the acceleration measurement data a'x, a'y and a'z is determined. The acceleration measurement data can be recorded with the acceleration sensor 10 in an operating position of the vehicle 100 which does not correspond to the calibration position 2 . In the operating position, the vehicle 100 is in a driving mode according to one embodiment. The spatial correction angle A is calculated based on the acceleration measurement data recorded in step S1 and as a function of the gravitational acceleration G acting on the acceleration sensor 10, as shown in FIG 2 explained, determined.

Reference List

2

calibration position

4

roadway

6

calibration surface

10

accelerometer

12

installation position

20

control unit

22

transmission control unit

30

transmission

100

vehicle

102

vehicle coordinate system

200

system

210

unit of account

ax

corrected x-acceleration measurement data

hey

corrected y accelerometer data

a.s

corrected z-acceleration measurement data

a'x

x acceleration measurement data

ayy

y acceleration measurement data

a'z

z-acceleration measurement data

G

acceleration due to gravity

S1

measurement data acquisition

S2

correction angle setting

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102019215671 A1 [0002]

Claims (10)

Method for calibrating an acceleration sensor (10) of a vehicle (100), with the steps: acquiring (S1) acceleration measurement data with the acceleration sensor (10) in a calibration position (2) of the vehicle (100), determining (S2) a spatial correction angle ( A) for attaching to acceleration measurement data (a'x, a'y, a'z), which can be detected with the acceleration sensor (10) in an operating position of the vehicle (100), based on the recorded acceleration measurement data and depending on the acceleration sensor (10) applied gravitational acceleration (G). procedure after claim 1 , wherein the steps of the method for calibrating an acceleration sensor (10) of a transmission control unit (22) of the vehicle (100) are carried out. procedure after claim 2 , wherein the acceleration sensor (10) is installed in the transmission control unit (22) of the vehicle (100). Method according to one of the preceding claims, wherein at least the step of acquiring (S1) acceleration measurement data is carried out when the vehicle (100) is stationary, in which the vehicle (100) is in the calibration position (2). Method according to one of the preceding claims, wherein at least the step of acquiring (S1) acceleration measurement data is carried out in a position of the vehicle (100) in which the vehicle (100) is on a horizontal calibration surface (6). Method according to one of the preceding claims, wherein the step of determining (S2) the correction angle (A) is carried out on the basis of a trigonometric function term which has recorded acceleration measurement data and the acting gravitational acceleration (G). System (200) for calibrating an acceleration sensor (10) of a vehicle (100), which is set up to carry out a method according to one of the preceding claims, with an acceleration sensor (10) for acquiring acceleration measurement data (a'x, a'y, a 'z) in a calibration position (2) of the vehicle (100), a computing unit (210) for determining a spatial correction angle (A) for attaching to acceleration measurement data (a'x, a'y, a'z), which with the acceleration sensor (10) can be detected in an operating position of the vehicle (100), based on the detected acceleration measurement data (a'x, a'y, a'z) and as a function of the acceleration of gravity (G) acting on the acceleration sensor (10). Control unit (20) for controlling a vehicle component, which has a system (200). claim 7 has and is set up to control the vehicle component based on detected acceleration measurement data. Control unit (20) after claim 8 , which is set up for controlling a transmission (30) of a vehicle (100). Vehicle (100), which a control unit (20) after claim 8 or 9 having.

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