System for detecting a wheel contact force, motor vehicle having such a system, and method for detecting a wheel contact force

Abstract

The invention relates to a system for detecting a wheel contact force on at least two wheels (10, 20, 30, 40) of an axle of a motor vehicle (50), comprising a respective measuring device (1, 2, 3, 4) per wheel (10, 20, 30, 40) for measuring different measured variables on the respective wheel (10, 20, 30, 40) and generating input variables for a control device (5) that is signal-connected to the respective measuring device (1, 2, 3, 4) and designed to process the input variables together with further influencing variables in a vehicle-specific system of linear equations for linking measured variables and influencing variables in order to determine at least one wheel contact force for the respective wheel (10, 20, 30, 40) as an output variable. The invention furthermore relates to a method for detecting a wheel contact force and to a motor vehicle having such a system.

Description

[0001] P240544

[0002] System for detecting wheel contact force, motor vehicle with such a system and method for detecting wheel contact force

[0003] The invention relates to a system for detecting wheel contact force and a motor vehicle comprising wheels and such a system. The motor vehicle can be configured as a work machine, tractor, construction machine, or crane. Furthermore, the invention relates to a method for determining wheel contact force.

[0004] For example, DE 102015 217 916 B4 discloses a motor vehicle comprising wheels and a device for determining a wheel contact force for each wheel of the motor vehicle, comprising at least one measuring device arranged at a point of action for measuring at least one force quantity at the point of action describing in direction and magnitude an effect force currently acting on the motor vehicle compared to a ground state, and a control device designed for calculating the wheel contact force from the at least one force quantity, the point of action and at least the weight and geometric structure of the motor vehicle.

[0005] The object of the invention is to create an alternative system for detecting wheel contact force for a motor vehicle. In particular, the system should be customizable for each vehicle. This object is achieved by the subject matter of claim 1. Preferred embodiments can be found in the dependent claims, the description, and the figures.

[0006] A system according to the invention for detecting a wheel contact force on at least two wheels of an axle of a motor vehicle comprises a measuring device for each wheel for measuring different measured variables at the respective wheel and generating input variables for a control unit connected to the respective measuring device via signal transmission. The control unit is configured to process the input variables together with other influencing variables in a vehicle-specific linear system of equations for linking measured and influencing variables in order to determine at least one wheel contact force for the respective wheel as an output variable. P240544

[0007] In other words, the measured and influencing variables are used to create and / or complete a model described by a system of linear equations, in particular by several linear equations. The input data is generated by the measuring devices during vehicle operation. The influencing variables are preferably entered manually by a user via a human-machine interface or determined by the control unit via dedicated sensors whenever the vehicle is recalibrated, especially when modifications are made to the vehicle. The measuring device includes, for example, several sensors for acquiring measured variables. The control unit is configured to receive data, in particular measured and influencing variables, to process this data, and to generate output variables from this data, in particular to generate a wheel contact force for the respective wheel.For example, the determined wheel contact force of the respective wheel can be displayed on a display device in the motor vehicle or transmitted to an external device for controlling and monitoring the motor vehicle.

[0008] Determining wheel contact forces on a motor vehicle is essential for evaluating various performance and safety aspects. For example, wheel contact forces directly influence the vehicle's traction, with higher contact forces at the drive wheels resulting in better power transfer to the ground. In particular, wheel contact forces affect ground pressure, with excessive ground pressure potentially leading to undesirable soil compaction. Wheel contact forces can be used to adjust tire pressure. Uneven wheel contact forces can cause the vehicle to tip over. To prevent tipping, the vehicle's load distribution can be adjusted according to the wheel contact forces. This can also reduce or better distribute wear. P240544

[0009] According to one embodiment, the measuring device comprises several sensors designed to detect different loads in different directions. This improves the measurement setup and measurement quality. For example, the sensors are arranged on a sensor ring, which is configured to be positioned between a bearing ring of a rolling bearing and a bearing support point formed on a stationary component. The bearing support point formed on the stationary component can support either the inner ring or the outer ring of the rolling bearing. Because the sensors do not come into direct contact with the rolling bearing or the stationary component, but rather with the sensor ring, which in turn comes into contact with the bearing support point and the bearing ring—that is, with the inner or outer ring of the rolling bearing—assembly is simplified.The connecting cables for the sensors can be bundled on the sensor ring and routed through the stationary component. Preferably, the sensor ring has at least one recess in the area of ​​the respective sensor to amplify the measurement signal of that sensor. In other words, the material is weakened in the area of ​​the recess to facilitate elastic deformation under load. Preferably, the at least one recess is formed on an inner circumferential surface. For example, the sensor ring is at least partially overmolded with a plastic to protect the respective sensor element from environmental influences such as temperature, fluids, and abrasion. For example, the plastic is polyurethane. This increases the service life of the measuring arrangement. The respective sensor element is arranged on a circumferential surface of the sensor ring.According to one embodiment, at least four sensors designed as strain gauges and evenly distributed around the circumference are arranged on the sensor ring. The strain gauges are intended for measuring strain and / or compression on the sensor ring. This improves the measurement setup and the measurement quality.

[0010] According to one embodiment, the respective measuring device has at least one sensor configured to detect the vehicle's speed, wheel slip, steering angle, tire pressure, track width, temperature, and / or gravitational acceleration. This measurement data is then made available to the control unit. This allows the wheel contact force for each wheel to be determined more precisely.

[0011] The invention also relates to a motor vehicle comprising several wheels and a system for detecting wheel contact force. The motor vehicle is designed as a work machine, tractor, construction machine or crane.

[0012] Furthermore, the invention relates to a method for detecting a wheel contact force on at least two wheels of an axle of a motor vehicle, wherein different measured variables are sensed at each wheel by a respective measuring device at the respective wheel, wherein the respective measuring device provides input variables for a control device connected to the respective measuring device via signal transmission, wherein the input variables together with further influencing variables are processed in a vehicle-specific linear equation system for linking the measured and influencing variables in order to determine at least one wheel contact force for the respective wheel as an output variable. Thus, at least two measuring devices are provided, wherein the respective measuring device is arranged at a respective wheel of the motor vehicle.The respective measuring device records input variables, such as loads in different directions, vehicle speed, wheel slip, steering angle, tire pressure, track width, temperature, and / or gravitational acceleration. Further data, particularly vehicle-specific data, are fed into the control unit as influencing variables to create or complete the vehicle-specific linear equation system and thereby develop a more accurate model. These linear equations establish relationships and conditions that describe the influence of the input variables and influencing variables, at least on the wheel contact force of each wheel.

[0013] The method can preferably be extended by optimizing the linear system of equations based on the input variables in an operating mode for training purposes using an algorithm. For example, a predefined movement of the vehicle is performed. The input variables are recorded during this process. Furthermore, the input variables are weighted, for example, by designated factors. The weighting of the input variables serves to fine-tune the linear system of equations.

[0014] For example, the output of the linear equation system could be a total vehicle weight, an indication of vehicle stability, and / or an overload. This allows a user to adjust the vehicle's load and / or operation to reduce wear and tear and increase the vehicle's stability and safety.

[0015] According to one embodiment, the input variables and influencing variables are further processed in a database. In particular, permissible and impermissible values ​​are stored in the database, and the input variables are compared with the values ​​in the database. Preferably, the input variables fed into the database are also compared with the output variables of the linear system of equations for error detection. In particular, the linear system of equations is checked by monitoring the input and output variables, especially by comparing at least the input variables with the values ​​in the database. For example, this can identify wear. In particular, an error message can be issued in case of deviations if a discrepancy between the model based on the linear system of equations and values ​​in the database exceeds a threshold.In particular, re-teaching the system may then be recommended.

[0016] Further measures improving the invention are described in more detail below, together with a description of a preferred embodiment of the invention, with reference to the figures.

[0017] Figure 1 is a highly simplified schematic representation of a motor vehicle according to the invention with a system for detecting a wheel contact force and P240544

[0018] Figure 2 is a flowchart illustrating a method for measuring a wheel contact force.

[0019] Figure 1 shows a highly simplified representation of a motor vehicle 50 according to the invention, including a system for detecting wheel contact force. The motor vehicle 50 can, for example, be a mobile work machine and has two axles, each with two wheels 10, 20, 30, 40. The system for measuring the wheel contact force at the wheels 10, 20, 30, 40 of the motor vehicle 50 comprises a measuring device 1, 2, 3, 4 for each wheel 10, 20, 30, 40 for measuring different parameters at the respective wheel 10, 20, 30, 40 and generating input signals for a control unit 5 connected to the respective measuring device 1, 2, 3, 4. Furthermore, additional influencing parameters are preferably entered manually by a user via a human-machine interface or determined by the control unit 5 via sensors provided for this purpose when the vehicle is recalibrated, particularly when modifications are made to the vehicle.

[0020] Each measuring device 1, 2, 3, 4 has several sensors 6, 7 configured to detect different loads in different directions. The sensors 6, 7 are arranged on a sensor ring 8, which is configured to be positioned between a bearing ring of a rolling bearing 11 and a bearing support point formed on a stationary component 12. The stationary component 12 is, for example, a housing part. Furthermore, each measuring device 1, 2, 3, 4 has at least one sensor 9 configured to detect the speed of the motor vehicle 50, the slip of a wheel 10, 20, 30, 40, a steering angle, a tire pressure, a track width, a temperature, and / or an acceleration due to gravity. For the sake of simplicity, only the sensors on the first measuring device 1 are shown here, while the other measuring devices 2, 3, 4 can be identical.

[0021] The control unit 5 is designed to process the input variables together with other influencing variables in a vehicle-specific linear equation system to form P240544. In this linear equation system, various measured variables and conditions are linked to determine, as an output variable, not only a wheel contact force for the respective wheel 10, 20, 30, 40, but optionally also a total vehicle weight, an indication of vehicle stability, and / or a vehicle overload. In particular, the output variables can be displayed on a display device in the vehicle 50 or transmitted to an external device for controlling and monitoring the vehicle 50.

[0022] Figure 2 shows a flowchart illustrating the inventive method for measuring the wheel contact force at the wheels 10, 20, 30, 40 of the motor vehicle 50 according to Figure 1. In a first method step 100, different measured variables at the respective wheel 10, 20, 30, 40 of the motor vehicle 50 are sensed by the respective measuring device 1, 2, 3, 4. The respective measuring device 1, 2, 3, 4 generates input variables for the control unit 5, which is connected to the respective measuring device 1, 2, 3, 4 via signal transmission. In a second method step 200, the input variables are processed in a linear system of equations together with other influencing variables to link different measured variables and conditions. In particular, this creates a model for the motor vehicle 50. The starting variable of the linear system of equations is at least one wheel contact force for each wheel 10, 20, 30, 40.

[0023] The input variables generated by the respective measuring device 1, 2, 3, 4 can optionally be fed into a database in a third process step 300. According to an optional fourth process step, the input variables fed into the database and the output variables of the linear system of equations for data monitoring are compared. In particular, in the case of larger or unexpected deviations in values, the linear system of equations can be optimized based on the input variables in an operating mode for training by an algorithm, especially through the application of artificial intelligence. P240544

[0024] Reference sign

[0025] 1 measuring device

[0026] 2 measuring device 3 measuring device

[0027] 4 Measuring device

[0028] 5 Control unit

[0029] 6 Sensor

[0030] 7 Sensor 8 Sensor ring

[0031] 9 Sensor

[0032] 10 wheels

[0033] 11 rolling bearings

[0034] 12 stationary component 20 wheel

[0035] 30 wheel

[0036] 40 wheel

[0037] 50 motor vehicles

Claims

1. P240544 Patent claims 1. System for detecting a wheel contact force on at least two wheels (10, 20, 30, 40) of an axle of a motor vehicle (50) comprising a respective measuring device (1 , 2, 3, 4) per wheel (10, 20, 30, 40) for measuring different measured quantities on the respective wheel (10, 20, 30, 40) and generating input variables for a control device (5) connected to the respective measuring device (1 , 2, 3, 4) via signal transmission, which is configured to process the input variables together with other influencing variables in a vehicle-specific linear system of equations for linking measured and influencing variables in order to determine at least one wheel contact force for the respective wheel (10, 20, 30, 40) as an output variable.

2. System according to claim 1, characterized in that the respective measuring device (1 , 2, 3, 4) has several sensors (6, 7) which are designed to detect different loads in different directions.

3. System according to claim 2, characterized in that the sensors (6, 7) are arranged on a sensor ring (8), wherein the sensor ring (8) is configured to be arranged between a bearing ring of a rolling bearing (11) and a bearing support point formed on a stationary component (12).

4. System according to one of the preceding claims, characterized in that the respective measuring device (1 , 2, 3, 4) has at least one sensor (9) which is configured to detect a speed of the motor vehicle (50), a slip of a wheel (10, 20, 30, 40), a steering angle, a tire pressure, a track width, a temperature and / or an acceleration due to gravity.

5. Motor vehicle comprising several wheels (10, 20, 30, 40) and a system for detecting a wheel contact force according to one of the preceding claims. P240544 6. Method for detecting a wheel contact force on at least two wheels (10, 20, 30, 40) of an axle of a motor vehicle (50), wherein different measured variables are sensed at the respective wheel (10, 20, 30, 40) by a respective measuring device (1, 2, 3, 4) at the respective wheel (10, 20, 30, 40), wherein the respective measuring device (1, 2, 3, 4) provides input variables for a control device (5) connected to the respective measuring device (1, 2, 3, 4) by means of signal transmission, wherein the input variables together with other influencing variables are processed in a vehicle-specific linear system of equations for linking the measured and influencing variables in order to determine at least one wheel contact force for the respective wheel (10, 20, 30, 40) as an output variable.

7. Method according to claim 6, characterized in that the linear system of equations is optimized on the basis of the input variables in an operating mode for learning by an algorithm.

8. Method according to claim 6 or 7, characterized in that the output variable of the linear system of equations is a total vehicle weight, an indication of vehicle stability and / or an overload.

9. Method according to claim 6, 7 or 8, characterized in that the input variables and influencing variables are further processed in a database.

10. Method according to claim 9, characterized in that the input variables in the database and the output variables of the linear system of equations are compared with each other for data monitoring.

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