Device, system and method for determining the gravitational acceleration on the basis of sensor data from an acceleration sensor of a vehicle

Abstract

The invention relates to a device (10) for determining the gravitational acceleration from sensor data from an acceleration sensor (20) of a vehicle, in particular an acceleration sensor (20) for construction vehicles and land vehicles or mobile machines, comprising an input interface (12) for receiving an acceleration signal from an acceleration sensor (20) and a state variable characteristic of the vehicle state; a processing unit (14) for determining the gravitational-acceleration value on the basis of the acceleration signal and on the basis of the characteristic state variable; and an output interface (16) for outputting the gravitational-acceleration value. The invention also relates to a corresponding system (50) and to a corresponding method.

Description

[0001] Device, system and method for determining the acceleration due to gravity based on sensor data from an acceleration sensor of a vehicle.

[0002] The present invention relates to a device, a system and a method for determining the acceleration due to gravity from sensor data of an acceleration sensor of a vehicle, in particular an acceleration sensor for construction and agricultural vehicles or mobile working machines.

[0003] Accelerometers are used in vehicles to draw conclusions about a vehicle's movement and orientation based on the measured quantities and acceleration signals. Various filters and algorithms are employed for this purpose. In addition to the accelerations acting on the vehicle, caused, for example, by braking or accelerating, an accelerometer is also inherently affected by the accelerations caused by gravity. These are referred to below as acceleration due to gravity.

[0004] The acceleration vector of gravity acts towards the Earth's center and can be used, for example, to determine the orientation of the accelerometer and thus the position of the sensor in space.

[0005] For example, DE102021210387A1 describes a method for calibrating a vehicle's accelerometer. For this purpose, the vehicle is placed in a calibration position in which a spatial correction angle is determined to account for the accelerometer's position in space. This determination is based on the acceleration due to gravity acting on the accelerometer, which is used as a constant. DE102010028827B4 and DE102009029216A1 also relate to methods for self-calibration and adjustment of an accelerometer, respectively, in which the acceleration due to gravity is assumed and used as a constant.

[0006] German patent DE 102016221827A1 proposes a method for calibrating an accelerometer, in which a normalized gravity vector is determined from the filtered acceleration values ​​of the sensor when the vehicle is stationary. This gravity vector is used to determine the position of the accelerometer in space and to perform a coordinate system transformation using a rotation matrix. This process assumes that the vehicle is stationary, which is determined using the acceleration values ​​from the accelerometer.

[0007] Acceleration values, as well as the acceleration due to gravity, are used in various algorithms and to determine other data in vehicles. For example, these values ​​are incorporated into equations for vehicle resistance and mass, as well as into the determination of vehicle dynamics. It has been found that additional errors occur in the algorithm calculations when the actual value of the acceleration due to gravity deviates from the assumed constant standard value of gravity (g = 9.81 m / s²). 2 ) deviates. Therefore, if there is a deviation between the actual acceleration due to gravity and the gravitational value used as a constant, or if a very precise calculation of the acceleration due to gravity is necessary for the algorithms and functions used within the vehicle, determining the current acceleration due to gravity is desirable.

[0008] There is therefore a need to determine the acceleration due to gravity using an accelerometer, especially when the accelerometer is moved around or subjected to strong vibrations. Such vibrations occur, for example, in mobile machinery, construction equipment or vehicles, and agricultural vehicles, particularly when these vehicles or machines are equipped with an internal combustion engine.

[0009] According to a first aspect, the present invention relates to a device for determining the acceleration due to gravity from sensor data of an acceleration sensor of a vehicle, in particular an acceleration sensor for construction and agricultural vehicles or mobile working machines, comprising

[0010] - an input interface for receiving an acceleration signal from an acceleration sensor and a state variable characteristic of the vehicle's condition; - a processing unit for determining the acceleration due to gravity based on the acceleration signal and the characteristic state variable; and

[0011] - an output interface for outputting the acceleration due to gravity.

[0012] According to a further aspect, the present invention relates to a system for determining the acceleration due to gravity based on sensor data from an acceleration sensor of a vehicle, in particular an acceleration sensor for construction and agricultural vehicles or a mobile working machine, comprising

[0013] - an accelerometer for measuring acceleration in at least two orthogonal spatial directions;

[0014] - a vehicle sensor for determining a state variable characteristic of the vehicle's condition, which includes information from a powertrain or output train of the vehicle; and

[0015] - a device according to one of the preceding claims.

[0016] Further aspects of the present invention relate to a vehicle with a corresponding system, a method designed according to the device, and a computer program product with program code for executing the steps of the method when the program code is executed on a computer. In addition, one aspect of the invention relates to a storage medium on which a computer program is stored which, when executed on a computer, effects the execution of the method described herein.

[0017] Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the present invention. In particular, the system, the method, and the computer program product can be implemented according to the embodiments described for the device in the dependent claims. According to the invention, the exact determination of the acceleration due to gravity from sensor data of an accelerometer is possible if no other accelerations act on the accelerometer. For this to be possible, the vehicle must be at rest, i.e., not moving.According to the invention, a characteristic state variable is used to determine whether the vehicle is stationary. This characteristic variable characterizes the vehicle's state, in particular its movement or standstill. For this purpose, state variables are used that are not based on the measurement result of an acceleration sensor. The characteristic state variable for the vehicle's state is therefore not characterized by an acceleration signal or an acceleration value from the vehicle's acceleration sensor. The characteristic state variable is based on information that differs from the acceleration signal. In this way, it is possible to detect when the vehicle is stationary independently of the acceleration signal and sensor. The determination of the acceleration due to gravity is therefore particularly robust.Furthermore, it is ensured that the standstill occurs independently of the acceleration value used to determine the acceleration due to gravity from the acceleration signal. This results in a high-quality determination of the acceleration due to gravity, ultimately expressing an accurate value for the acceleration due to gravity in the current situation.

[0018] According to a preferred embodiment, the device has a storage unit for saving the determined acceleration due to gravity. The storage unit can also optionally serve to store an initial value for the acceleration due to gravity. For example, the gravitational acceleration value g, assumed to be a constant, can be used. This ensures that at least one value for the acceleration due to gravity is available for algorithms and vehicle dynamics calculations, particularly when the location- and / or situation-dependent acceleration due to gravity has not yet been determined. Any resulting inaccuracies and errors due to the deviation between the assumed constant gravitational acceleration value and the actual acceleration due to gravity must initially be accepted.Preferably, the processing unit of the device is configured to check, based on a predefined change criterion, whether a gravity acceleration value stored in the memory unit can be used and output. A plausibility check can be performed during this process. For example, the determined gravity acceleration value is compared with the stored value. If the deviation is only a few percent (e.g., less than 10%, less than 5%, less than 1%, less than 0.1%, less than 0.01%, less than 0.001%), the stored value can be used. In this case, it is not necessary to save a newly determined value. This is particularly relevant if only a small change in the vehicle's position has occurred between two measurements of the gravity acceleration, so that the values ​​to be compared are nearly identical.

[0019] In a preferred embodiment, the processing unit is configured to determine the vehicle speed based on the characteristic state variable that reflects the vehicle's state. In particular, a vehicle standstill is defined. Preferably, the characteristic state variable is based on information from the powertrain. For example, sensor values ​​from the powertrain can form the basis for the characteristic state variable. Various sensor values ​​from the powertrain present in the vehicle can be used. For example, it can be checked whether a gear is engaged in the transmission, whether the vehicle's brakes are applied, or whether a sensor value determined by a wheel sensor indicates that one or all wheels are stationary. Alternatively, the characteristic state variable can be based on an output sensor in the output shaft, i.e., between the transmission and the axle.The output shaft is understood here as part of the powertrain. Naturally, the characteristic state variable can encompass multiple pieces of information from one or more sensors, or other information present in the vehicle.

[0020] In a preferred embodiment, the processing unit is configured to determine whether a predefined rest criterion is met. Determining compliance with the rest criterion is based on the characteristic state variable. This allows not only the determination of whether the vehicle is stationary but also whether it is at rest, meaning that no disruptive influences, such as vibrations or roll movements, are acting on the acceleration sensor. The predefined rest criterion can indicate, or enable, whether other sources of acceleration are switched off when the vehicle is stationary, or at least their influence is reduced to such an extent that they have only a practically negligible effect on determining the acceleration due to gravity from the acceleration signal of the acceleration sensor and do not affect the result of the acceleration due to gravity determination.The characteristic state variable can therefore include information on standstill and rest, including information on whether further disturbances are excluded or negligible, such as vibrations or tilting movements caused by external loads in working machines. The predefined rest criterion is preferably chosen or defined such that no significant influences on the acceleration sensor and its measurement prevail when the criterion is met.

[0021] Knowledge of the vehicle's state, described by its characteristic state variable, can be derived via a signal interface, such as a CAN bus. The device's input interface can, for example, be a CAN interface. The device can preferably be integrated, for example, into a Transmission Control Unit (TCU).

[0022] In a preferred embodiment, the processing unit of the device is configured to determine the position of the accelerometer relative to the acceleration due to gravity, based on the determined acceleration due to gravity value and optionally based on the acceleration signal of the accelerometer.

[0023] In a preferred embodiment of the device, the acceleration signal from the accelerometer comprises at least two acceleration values ​​in the direction of the axes of a Cartesian coordinate system, preferably one value in the Z-direction, i.e., in the vertical direction of the accelerometer. Preferably, the acceleration signal comprises at least one acceleration value each in the Z-direction and in the X-direction or Y-direction. Such an acceleration signal would be acquired and output by a 2D sensor. In a preferred three-dimensional accelerometer, the acceleration signal preferably comprises acceleration values ​​in all three spatial directions of a Cartesian coordinate system. In this way, it is easy to determine the value for the acceleration due to gravity from the acceleration values ​​of the three spatial directions.

[0024] In a preferred embodiment, the characteristic state variable that is processed includes information indicating that sources influencing the determination of the acceleration due to gravity are switched off or generate a disturbance value below a predefined disturbance threshold. The disturbance threshold is preferably defined such that the generated disturbances have no practical influence on the determination of the acceleration due to gravity. This information can be verified using a quiescent criterion. Alternatively, sources that generate a known disturbance value, such as a known vibration pattern or the vibration pattern of an internal combustion engine, can also be accepted, so that the known disturbance value can be compensated for and / or factored out in a subsequent algorithm.

[0025] In a preferred embodiment of the device, characteristic state variables are processed, comprising data from a vehicle sensor, wherein the vehicle sensor is not the accelerometer. Preferably, data from a sensor in the vehicle's powertrain or output shaft is used. Alternatively or additionally, data from one or more wheel sensors, a speed sensor, a clutch sensor, or a brake sensor can be used to describe the characteristic state variable. The characteristic state variable can comprise multiple pieces of information from different sensors. It can include information about the vehicle's standstill and resting state; this information can be based on multiple sensors, preferably not on signals from the accelerometer.In a preferred embodiment, the device is configured to detect vehicle movement based on a characteristic state variable, wherein the characteristic state variable is determined by a sensor other than the acceleration sensor. Preferably, the vehicle's movement or standstill is detected by means of a sensor in the drivetrain or the output train.

[0026] In a further preferred embodiment, the characteristic state variable not only represents the vehicle's standstill. It can also contain information indicating that the vehicle is at rest. The vehicle is at rest when it is stationary and has no other sources acting on the acceleration sensor in such a way as to influence the determination of the acceleration due to gravity. In this preferred case, the characteristic state variable thus includes information about whether the vehicle is moving and whether it is also at rest. For both criteria, the characteristic state variable is preferably based on sensor values ​​from the powertrain or the output train, or other information available in the vehicle.

[0027] In a vehicle, especially a construction vehicle or mobile work machine, the acceleration sensor is subjected to accelerations of large amplitude, which can have various causes. For example, vibrations can be generated by the work machine or construction vehicle itself, such as by the drive unit, which can occur even when stationary, or by loading or unloading the mobile work machine or construction vehicle. For instance, the application of earth to a dump truck can cause it to vibrate or rock. Other factors that can cause vibrations are related to the control of the vehicle's working hydraulics or the vehicle's control system. Vibrations that occur while driving can be caused by driving on uneven surfaces, over potholes, or by cornering, which can lead to centripetal accelerations, for example.Such disturbances are excluded by the device and method according to the invention, since they are detected and the determination of the acceleration due to gravity preferably only takes place when the vehicle is both stationary and at rest, i.e. free from unacceptable influences that are relevant for determining the acceleration due to gravity in practice.

[0028] According to the invention, the method for determining the acceleration due to gravity comprises a step of receiving an acceleration signal from an acceleration sensor of the vehicle. A further step of the method involves receiving a state variable characteristic of the vehicle's state, wherein the state variable comprises information from the vehicle's powertrain or output train. In a further step, the acceleration due to gravity is determined based on the acceleration signal from the acceleration sensor and on the characteristic state variable. A further step involves outputting the determined acceleration due to gravity value so that it can be used in other devices of the vehicle. For example, the determined acceleration due to gravity can be supplied to the control unit or evaluation units that perform the vehicle dynamics calculations.

[0029] Preferably, the method may include further steps. At least one of the following further steps is preferably performed by the method:

[0030] One step involves determining the need to replace a stored acceleration due to gravity value or an initial value for the acceleration due to gravity. A further step involves determining the vehicle speed based on the characteristic state variable. This characteristic state variable can represent either the vehicle speed or a standstill.

[0031] If the evaluation of the characteristic state variable shows that the vehicle speed is zero, the next step involves identifying sources that influence the determination and calculation of the acceleration due to gravity. A further step involves evaluating these sources and verifying, based on a rest criterion and the state variable, whether the vehicle is at rest. The rest criterion could, for example, be a threshold for an acceptable disturbance value. For instance, the rest criterion could represent a vibration threshold for any vibrations occurring in the vehicle.

[0032] Once the value of the acceleration due to gravity has been determined, a plausibility check of the calculated value can be performed in a further step. This can be done, for example, by comparing it with the constant acceleration due to gravity or with previous values.

[0033] Another optional step involves storing the determined acceleration due to gravity in a memory unit. Optionally, this can involve overwriting an existing value in the memory.

[0034] In a preferred embodiment of the device, the device is configured to receive an acceleration signal that has been filtered, preferably with a low-pass filter, very preferably with a first-order low-pass filter, and particularly preferably with a PT1 filter. In a further preferred embodiment, the filtering of the acceleration signal from the accelerometer takes place within the device, preferably in the processing unit. A low-pass filter, for example a first-order PT1 filter, can be used for this purpose.

[0035] The invention is described and explained in more detail below with reference to some selected embodiments in conjunction with the accompanying drawings. These show:

[0036] Fig. 1 shows a schematic representation of the device according to the invention for determining the acceleration due to gravity;

[0037] Fig. 2 a vehicle with a system according to the invention;

[0038] Fig. 3 shows a basic sequence of the inventive method for determining the acceleration due to gravity; and Fig. 4 shows a particular embodiment of the method for determining the acceleration due to gravity.

[0039] Figure 1 shows the device 10 according to the invention for determining the acceleration due to gravity from sensor data of an accelerometer 20, which is connected to an input interface 12 of the device 10. In addition to the input interface 12, the device 10 comprises a processing unit 14, an output interface 16 for outputting a determined acceleration due to gravity value, and an optional storage unit 18 for storing the acceleration due to gravity value.

[0040] The accelerometer 20 provides an acceleration signal. Preferably, the accelerometer 20 is a three-dimensional accelerometer such that the acceleration signal includes acceleration values ​​in each of the three Cartesian coordinate directions, i.e., one acceleration value each for the X, Y, and Z directions.

[0041] The input interface 12 serves not only to receive the acceleration signal from the acceleration sensor 20, but also to receive a state variable that is characteristic of the vehicle's state. The input interface 12 is therefore connected to a device 30 that provides this characteristic state variable. This could, for example, be a vehicle sensor 32 of the powertrain or the output train (output train sensor 34) of a vehicle.

[0042] A control unit 40 is connected to the output interface 16, to which the determined acceleration value is transferred in order to be further processed in the control unit 40, for example to determine the driving dynamics or similar.

[0043] The device 10, together with the acceleration sensor 20 and the vehicle sensor 32 or device 30, forms a system 50 according to the invention. In an alternative embodiment not shown here, the device 10, including the input interface 12, the processing unit 14, the storage unit 18, and the output interface 16, can also be integrated into the control unit 40, for example, a transmission control unit. The method according to the invention can thus sometimes be implemented as a software function on the control unit 40.

[0044] Figure 2 shows a vehicle 60 with such a system 50. The vehicle 60 can be, for example, a dump truck shown, another construction vehicle, or a mobile work machine.

[0045] Figure 3 shows a schematic flowchart of the inventive method for determining the acceleration due to gravity based on sensor data from a vehicle's accelerometer. In a first step S10, an acceleration signal from an accelerometer is received. In a further step S12, a state variable characteristic of the vehicle's state is received, comprising information from the vehicle's powertrain or output train. A further step S14 relates to determining the acceleration due to gravity value based on the acceleration signal and the received characteristic state variable. In a step S16, the determined acceleration due to gravity value is output, preferably via the output interface.

[0046] The procedure may optionally include further steps. One optional step, S20, involves determining the need to replace a gravity acceleration value stored in a memory unit or an initial value for gravity acceleration.

[0047] Another optional step, S22, involves determining the vehicle speed based on the characteristic state variable.

[0048] Step S24 is aimed at identifying sources that could influence the determination of the acceleration due to gravity or its value. This optional step is only executed if the vehicle speed is zero, i.e., if the vehicle is stationary. Step S26, which is also optional, checks whether the vehicle is at rest, meaning no influencing sources or sources of disturbance could be identified. This check is performed using a rest criterion and is based on the state variable. The state variable can contain further information, such as information about sources emitting disturbances or about disturbances that can be detected.

[0049] An optional step, S28, is designed to check the plausibility of the determined acceleration due to gravity. This can be done using predefined criteria, for example, by comparing it with the Earth's gravity stored as a constant or with the Earth's gravity value g (g = 9.81 m / s²). 2 Step S28 is executed after step S16, as can be seen in Figure 3.

[0050] Another optional step S30 concerns storing the determined acceleration due to gravity in a storage unit, whereby in this step it may optionally be provided to overwrite an existing stored value of the acceleration due to gravity.

[0051] Figure 4 shows an alternative embodiment of a method for determining the acceleration due to gravity, which includes several feedback loops. In step BS10, an acceleration due to gravity signal from an accelerometer is received. In a further step BS12, it is checked whether a value for the acceleration due to gravity stored in a memory unit 18 can be used. This step starts with an initial value for the acceleration due to gravity, which is stored, for example, in the memory unit 18. The initial value could, for example, be the standard acceleration due to gravity constant g = 9.81 m / s². 2 The stored value of the acceleration due to gravity can be made available to other functions or algorithms that require this value.

[0052] In a further step, BS14, the system checks whether an update to the existing acceleration due to gravity is necessary. This is done according to predefined criteria and can be triggered or initiated externally, for example, by a control unit. The criteria that trigger an update can be met, for example, if no valid initial value for the acceleration due to gravity exists, if a certain period of time has elapsed (which can be freely parameterized), if the vehicle's ignition is switched on, if one or more of the vehicle's control units are powered on or switched on, or if one or more control units, or a specific control unit, are shut down. An update of the value can be triggered by a service technician or a service signal from the vehicle. This can be done automatically or manually.The criterion for updating the acceleration due to gravity can be triggered by evaluating the GPS position, for example, if the GPS position has changed significantly from its original value or if a change in the acceleration due to gravity is expected. Geographical data can be used for this purpose. If the vehicle is equipped with a pressure sensor, a significant change in ambient pressure can also initiate an update of the acceleration due to gravity value. Furthermore, a predetermined mileage or distance traveled could trigger an update. Similarly, the acceleration due to gravity can be updated after extended periods of vehicle inactivity.

[0053] In step BS16, the vehicle speed is determined. The goal for determining the acceleration due to gravity is to minimize interference from external factors affecting the acceleration sensor. For this purpose, it is advantageous if the vehicle speed is zero, i.e., the vehicle is stationary, since even at a constant speed, it cannot be guaranteed that the detected acceleration results solely from the acceleration due to gravity. For example, uneven road surfaces or potholes can undesirably influence the calculation.

[0054] If the vehicle is not stationary, which is checked in step BS18, feedback is sent to step BS12. Otherwise, step BS20 follows, in which further sources of acceleration are determined. These are sources that can cause disturbances that would distort the determination of the acceleration due to gravity from the acceleration signal of the accelerometer. Therefore, if the vehicle is stationary, it is checked whether there are any other "acceleration sources" in the vehicle that could negatively affect the determination of the acceleration due to gravity.These sources include, for example, the control of the working hydraulics of a mobile work machine, the control of the chassis settings, a dynamic change in the speed of the drive motor, a shifting in the transmission, a loading or unloading of the vehicle, especially in the case of mobile work machines or construction vehicles, which can be detected via a weight sensor or by observing acceleration data in the vehicle when these change abruptly for a short time.

[0055] If step BS22 detects that the vehicle is not at rest, feedback is sent to step BS12. Otherwise, step BS24 determines the acceleration due to gravity from the sensor signal and the accelerometer data. The detected acceleration can then be considered a direct result of the acceleration due to gravity.

[0056] If a 3D acceleration sensor is used, the acceleration due to gravity g is determined from:

[0057] With a 2D acceleration sensor, the sensor's installation position and the vehicle's position must ensure that it is possible to determine the acceleration due to gravity using both axes.

[0058] If the X-axis of acceleration lies in the longitudinal direction of the vehicle and the Z-axis corresponds to the acceleration along the vertical axis of the vehicle, g can be determined by Determine. In this case, the vehicle must not be tilted laterally; the roll angle must therefore be 0 degrees. In any case, the tilt must be known in order to be able to subtract it from the acceleration due to gravity, if necessary. If the Y-axis of acceleration lies in the transverse direction of the vehicle (lateral) and the Z-axis corresponds to the acceleration along the vehicle's vertical axis, the acceleration can be determined by To determine the pitch angle, the vehicle must not be tilted; therefore, the pitch angle must be 0 degrees, or the tilt must be known in order to take it into account and factor it out when determining the acceleration due to gravity.

[0059] For a one-dimensional acceleration sensor, it must be possible to determine the acceleration due to gravity using only one axis. The Z-axis of the acceleration must correspond to the vehicle's vertical axis. The measured acceleration is then equal to the acceleration due to gravity. In this case, the vehicle must not be tilted in either the longitudinal or lateral direction, or both tilts must be known to eliminate these influences.

[0060] If the vehicle is not at rest, but the occurring accelerations are known, they can be filtered out from the acceleration sensor data (i.e., the acceleration signal) before the acceleration due to gravity is determined. Such disturbances can be caused, for example, by a drive motor when the engine is idling.

[0061] In a further step, BS26, the plausibility of the determined value for the acceleration due to gravity is checked. If the plausibility check is negative, the process returns to step BS12 via a feedback loop. Otherwise, in step BS28, the stored value for the acceleration due to gravity is updated with the newly determined value.

[0062] In contrast to the method presented here, the acceleration due to gravity can also be calculated even if vibrations occur in the vehicle and would affect the acceleration due to gravity. This leads to a plausible and suitable value for the acceleration due to gravity if the vibration patterns are known and can be factored out or filtered out. This can be the case, for example, when the vehicle is stationary, i.e., not moving, but the drive motor continues to run.

[0063] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as examples and not as limiting. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to a person skilled in the art when using the present invention and upon a detailed analysis of the drawings, the disclosure, and the subsequent claims.

[0064] In the claims, the words "comprise" and "with" do not preclude the presence of further elements or steps. The undefined article "a" or "an" does not preclude the presence of multiple elements. A single element or unit can perform the functions of several of the units mentioned in the claims. An element, unit, interface, device, and module can be implemented partially or completely in hardware and / or software. The mere mention of some measures in several different dependent claims is not to be understood as precluding the advantageous use of a combination of these measures. Reference numerals in the claims are not to be interpreted restrictively.

[0065] Reference mark

[0066] device

[0067] Input interface, processing unit, output interface, storage unit

[0068] Accelerometer device

[0069] Vehicle sensor

[0070] Output train sensor

[0071] Vehicle control unit system

Claims

Patent claims 1. Device (10) for determining the acceleration due to gravity from sensor data of an acceleration sensor (20) of a vehicle, in particular an acceleration sensor (20) for construction and agricultural vehicles or mobile working machines, comprising - an input interface (12) for receiving an acceleration signal from an acceleration sensor (20) and a state variable characteristic of the vehicle state; - a processing unit (14) for determining the acceleration due to gravity value based on the acceleration signal and on the characteristic state variable; and - an output interface (16) for outputting the acceleration due to gravity value.

2. Device (10) according to claim 1, wherein the device (10) comprises a storage unit (18) for storing the acceleration due to gravity value and / or for storing an initial value of the acceleration due to gravity.

3. Device (10) according to claim 2, wherein the processing unit (14) is configured to check, on the basis of a predefined change criterion, whether a gravity acceleration value stored in the storage unit (18) can be used and output.

4. Device (10) according to one of the preceding claims, wherein the processing unit is configured to determine the vehicle speed based on the characteristic state variable, wherein the characteristic state variable is preferably based on information from the powertrain.

5. Device (10) according to one of the preceding claims, wherein the processing unit (14) is configured to determine, on the basis of the characteristic state variable, whether a predefined rest criterion is met.

6. Device (10) according to one of the preceding claims, wherein the processing unit (14) is configured to determine the position of the acceleration sensor (20) generating the acceleration signal relative to the acceleration due to gravity, based on the determined acceleration value and optionally on the acceleration signal.

7. Device (10) according to one of the preceding claims, wherein the acceleration signal comprises at least one acceleration value in the z-direction and in the x-direction or y-direction, preferably one acceleration value in all three spatial directions of a Cartesian coordinate system.

8. Device (10) according to one of the preceding claims, wherein the characteristic state variable comprises information that sources influencing the determination of the acceleration due to gravity are switched off, generate a disturbance value below a predefined disturbance threshold, or generate a known disturbance value that can be compensated and / or subtracted.

9. Device (10) according to one of the preceding claims, wherein the characteristic state variable comprises data from a vehicle sensor (32), preferably data from a sensor in the drive train or in the output train of the vehicle or from a wheel sensor, a speed sensor, a clutch sensor or a brake sensor.

10. System (50) for determining the acceleration due to gravity based on sensor data from an acceleration sensor (20) of a vehicle (60), in particular an acceleration sensor (20) for construction and agricultural vehicles or a mobile working machine, comprising an acceleration sensor (20) for measuring the acceleration in at least two orthogonal spatial directions; a vehicle sensor (32) for determining a state variable characteristic of the vehicle state, which includes information from a powertrain or output train of the vehicle (60); and a device (10) according to any of the preceding claims.

11. Vehicle (60), in particular a construction or agricultural vehicle or mobile working machine, with a system (50) according to claim 10.

12. Method for determining the acceleration due to gravity based on sensor data from an acceleration sensor (20) of a vehicle (60), in particular an acceleration sensor (20) for construction and agricultural vehicles or mobile working machines, comprising the following steps: Receiving an acceleration signal from the accelerometer (20); Receiving a state variable characteristic of the vehicle's condition, which includes information from a powertrain or output train of the vehicle; Determination of the acceleration due to gravity based on the acceleration signal and the characteristic state variable; and Outputting the acceleration due to gravity.

13. The method of claim 12, comprising at least one of the further steps: Determining the need to replace a gravity acceleration value or initial value stored in a memory unit; Determining the vehicle speed based on the characteristic state variable; When the vehicle speed is zero, determine sources that influence the determination of the acceleration due to gravity; Check whether the vehicle is at rest using a rest criterion and based on the state variable; Checking the plausibility of the determined acceleration due to gravity value; Saving the determined acceleration due to gravity value and optionally overwriting an existing stored value for acceleration due to gravity.

14. Computer program product comprising program code which, when executed by a computer, causes the computer to perform the steps of the method according to claim 12 or 13.

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