System and method for detecting a lateral impact event on the steering system of at least one axle in a motor vehicle

Abstract

The invention relates to a system (10) for detecting a lateral impact event at the steering system on at least one chassis axle (14a, 14b) in a motor vehicle (12), comprising a steering system and a control unit (18) with an evaluation unit (19). The steering system has at least one electric motor (16a, 16b). The electric motor (16a, 16b) is connected to the control unit (18) via a signal. The evaluation unit (19) receives at least one first input signal, which is compared with defined limit conditions. If the limit conditions are exceeded, the control unit (18) generates a warning signal, which is visualized to inform the driver of the motor vehicle (12). The invention is characterized in that the first input signal is an electrical signal, in particular a voltage or current signal.At least one measuring unit (20a, 20b) is provided which generates the electrical signal by measuring an induced voltage or induced current in the electric motor (16a, 16b).

Description

[0001] The invention relates to a system for detecting a lateral impact event at the steering system on at least one axle in a motor vehicle according to the type specified in the preamble of claim 1. The invention further relates to a method for detecting a lateral impact event at the steering system on at least one axle in a motor vehicle according to the type specified in the preamble of claim 9.

[0002] To counteract load cases such as sideways curb impacts, steering components are designed with safety factors and a failure-tolerant damage chain is constructed. Typically, the tie rod deforms first, resulting in wheel misalignment, which the driver or, at the latest, a workshop should detect during the next service, without further mechanical failure of other components. The steering gear, located downstream of the tie rod in the damage chain, is over-dimensioned compared to its actual load limits to enable this failure-tolerant damage chain and remain undamaged until a deformed tie rod definitively indicates the event. The steering system must fail last or be designed with a specified safety margin relative to the components upstream in the damage chain.Consequences of this over-dimensioned mechanical design with high safety factors due to the failure-tolerant damage chain are an unnecessarily increased weight, higher unit costs and limited reusability of steering modules in vehicles with increased axle loads.

[0003] Systems for detecting lateral impacts on the steering system of at least one axle of a motor vehicle are already known. These systems typically employ one or more sensors, particularly acceleration sensors, to monitor lateral load cases, such as sideways contact with a curb. These sensors are located, among other places, in the side of the vehicle's body. This allows the mechanical impulse caused by the abrupt lateral force, which is transmitted from the tie rod to the steering gear by this lateral load case, to be detected indirectly. However, this detection method has the disadvantage that the sensors located in the vehicle's body make spatial resolution with respect to the axles difficult, and the measurement or detection is also inaccurate.

[0004] Such a detection system is disclosed in EP 2 848 437 A1. The system uses sensors that record parameters such as steering angle, steering torque, and vehicle speed to detect irregularities and potential damage in the steering system. The system works by comparing the measured values ​​(e.g., steering angle to vehicle movement) to determine whether deviations from normal steering responses occur. These deviations could indicate mechanical problems, wear, or damage in the steering system. Additionally, the sensor data is aggregated and evaluated in a control unit, enabling a diagnosis of the steering system's condition.

[0005] Further systems for detecting a lateral impact event on chassis components on at least one axle of a motor vehicle are known, among others, from DE 10 2004 021 550 A1 and EP 0 778 461 B1. In a known manner, acceleration sensors are used as input signals, which can generally indicate an impulse-like stress on axle components, but do not allow for a precise resolution of which components, and in particular the steering system, were affected by the impulse.

[0006] It is therefore an object of the invention to further develop a system for detecting a lateral impact event at the steering on at least one chassis axle in a motor vehicle in such a way that the spatial resolution with respect to the chassis axes of the motor vehicle and the accuracy of the measurement are improved.

[0007] This problem is solved by the characterizing features of claim 1 in conjunction with its preamble features.

[0008] Subclaims 2 to 8 represent advantageous embodiments of the invention.

[0009] In a known manner, a system for detecting a lateral impact event at the steering system of at least one axle of a motor vehicle comprises a control unit with an evaluation unit and a steering system. The steering system includes at least one electric motor. The steering system is connected to the control unit. The evaluation unit receives an initial input signal, which is compared with predefined limit values. If the limit values ​​are exceeded, the control unit generates a warning signal, which is visualized to inform the driver of the motor vehicle.

[0010] According to the invention, the first input signal is an electrical signal, in particular a voltage or current signal. At least one measuring unit is provided which generates the electrical signal by measuring an induced voltage or an induced current in the electric drive train. The electric drive train is understood to be the drive of the steering gear of the steering system. The measurement can be performed directly in the electric motor or in peripheral electrical components.

[0011] The mechanical impulse transmitted via the vehicle's tie rod to the steering system, and consequently to the electric drivetrain (e.g., the electric motor), generates an induced voltage in the motor's windings. This voltage produces a signal waveform complementary to the mechanical impulse. As a result, the initial input signal is captured directly at the steering system by at least one measuring unit, ensuring high detection accuracy. Furthermore, the input signal can pinpoint the location of any steering system damage to the vehicle axle.

[0012] According to a further advantageous embodiment of the invention, the warning signal is displayed via a warning message in the vehicle's cockpit. This clearly illustrates the warning signal to the driver, informing them of possible damage to the steering system and enabling them to take appropriate action, such as a visit to a workshop.

[0013] Preferably, at least one sensor, in particular an acceleration sensor, is provided. The evaluation unit receives a second input signal generated by the at least one sensor. By fusing the first and second input signals, the accuracy of the system's detection is increased, as a more complete picture of the potential lateral impact event is ensured. The risk of false alarms and uncertainties in detection is reduced. By combining the signals, correlations between these signals can be analyzed, which would not be visible individually. This makes it easier to distinguish between normal and abnormal states of the steering system. Furthermore, by incorporating the second input signal, the reliability of the spatial resolution of the detection with respect to the vehicle axles can be increased when the measuring unit is located on one axle and the sensor on the other.

[0014] Preferably, the sensor is positioned in the region of at least one axis such that damage to at least one axis can be reliably attributed to that axis. This increases the system's robustness against other external influences. The risk of false detections due to the sensor's second input signal is reduced.

[0015] According to a further advantageous embodiment of the invention, the boundary conditions are defined as a time interval and a signal peak. This allows short-term anomalies or abrupt changes in the input signal(s) to be detected. These lateral mechanical impulses acting on the steering system are expressed by short peaks or peak values. This ensures high sensitivity to sudden changes, which often indicate incipient damage. Temporal resolution and targeted peak analysis provide more precise fault localization.

[0016] Preferably, the steering system is designed as a steer-by-wire system.

[0017] Preferably, the control unit includes a memory unit. The warning signal is stored in the memory unit along with an assignment information, in particular a timestamp. This makes the potential damage and the associated warning signal traceable and retrievable, so that an unnoticed or overlooked incident can be detected retrospectively, allowing the steering system to be examined for potential damage. Further assignment information could include, for example, the area of ​​the vehicle or the intensity of the mechanical impulse.

[0018] According to a further advantageous embodiment of the invention, several electric motors are provided. Several first input signals are generated by the measuring unit. The measuring unit generates the electrical signals by measuring the induced current or voltage at each electric motor or its peripheral electrical components on different chassis axles. This ensures that, through direct measurement at the chassis axles, a lateral impact event can be assigned to one of the chassis axles, thereby improving spatial resolution.

[0019] Another aspect of the invention relates to a method for detecting a lateral impact event on the steering system of at least one axle in a motor vehicle with a system according to one of the preceding claims comprising the following method steps: - Generating at least one first input signal by the at least one measuring unit or generating at least one first and second input signal; - Receiving the first input signal or the first and second input signals by the evaluation unit; - Comparison of the first input signal or the first and second input signals with the limit conditions by the evaluation unit; - Generating a warning signal when the limit conditions are exceeded by the control unit; - Illustrating the warning signal via a warning message in the cockpit of the motor vehicle through the display unit.

[0020] According to a further advantageous embodiment of the invention, the method comprises the additional process step: - Saving the warning signal with an assignment information in the storage unit.

[0021] Preferably the method includes the additional process step: - Displaying a warning signal after each restart of the vehicle. This also informs future users of the vehicle that an event has occurred that affected or could affect driving performance.

[0022] Further advantages and application possibilities of the invention will become apparent from the following description in conjunction with the embodiment shown in the drawing. Fig. 1 a schematic view of a system according to the invention in a motor vehicle

[0023] In the Fig. Figure 1 shows a schematic view of a system 10 according to the invention in a motor vehicle 12.

[0024] System 10 is installed in a motor vehicle 12. The motor vehicle 12 has two chassis axles 14a, 14b, namely a front axle 14a and a rear axle 14b. Both chassis axles 14a, 14b are part of the steering system of the motor vehicle 12 and each has a steering gear with an electric drive train comprising an electric motor 16a, 16b. This is therefore a rear-axle steering system (RAS). Tires 17a, 17b are arranged at the two ends of the chassis axles 14a, 14b. The tires 17a, 17b are each connected to the chassis axle 14a, 14b via a tie rod. System 10 also includes a control unit 18 with an evaluation unit 19. The steering gears are not self-locking. This means that an external force on the tie rods towards the steering gear causes movement in the steering gear and the tie rods themselves, all the way to the motor unit of the steering gear.

[0025] Each electric motor 16a, 16b is equipped with a measuring unit 20a, 20b. The measuring units 20a, 20b are each connected to the evaluation unit 19 of the control unit 18 via a signal connection. The measuring units 20a, 20b each generate an electrical signal by measuring the induced voltage in the windings of the electric motors 16a, 16b. The electrical signal can also be in the form of an induced current. Furthermore, it is possible to measure peripheral electrical components, such as resistors or capacitors downstream of the electric motor 16a, 16b, in the electric drive train. This electrical signal is forwarded to the evaluation unit 19 as the first input signal.

[0026] Furthermore, a sensor 22, designed as an acceleration sensor, is arranged in the lateral area of ​​the motor vehicle 12 near the rear axle 14b. The sensor 22 is connected to the evaluation unit 19 of the control unit 18 via a signal connection. The sensor 22 generates a second input signal that is forwarded to the evaluation unit 19.

[0027] The control unit 18 is connected to a display unit 24 via signal transmission. The display unit 24 is positioned in the cockpit of the motor vehicle 12 such that the driver of the motor vehicle 12 can perceive it within their field of vision during operation. Furthermore, a storage unit 26 is provided, which is connected to the control unit 18 via signal transmission.

[0028] The evaluation unit 19 compares the input signals with predefined boundary conditions. These are defined as time intervals and signal peaks. By defining the boundary conditions as signal peaks and time intervals, the system 10 can better understand anomalies in a specific context and more precisely identify a lateral impact event. This aids in diagnosis and prevents unnecessary false alarms.

[0029] If the load case of sideways curb sliding occurs, the resulting mechanical impulse generates a peak or exceedance of the limit conditions in the input signal curves of at least one measuring unit 20a, 20b and / or the sensor 22. This exceedance of the limit conditions causes the control unit 18 to generate a warning signal and forward this warning signal to the display unit 24. The display unit 24 then illustrates the warning signal to the driver via a warning light or a warning message on a display in the cockpit of the vehicle 12.

[0030] Furthermore, the warning signal is stored in memory unit 26 along with defined assignment information, such as a timestamp. Memory unit 26 is designed so that it can be read out.

[0031] The warning signal can be displayed again each time the vehicle is restarted.

[0032] The boundary conditions of the evaluation unit 19 can be configured such that different levels of a warning signal are defined. These depend on the strength of the mechanical impulse caused by the lateral impact event.

[0033] A first stage is represented by a slight exceedance of the limit conditions. In this case, the control unit 18 generates an initial warning signal, which is stored with assignment information in the memory unit 26. The memory unit 26 can then be read out, for example, at the next service appointment in a specialist workshop, and the steering system on the chassis axles 14a, 14b of the vehicle 12 can then be checked.

[0034] A second stage represents a moderate exceedance of the limit values. In this case, the control unit 18 generates a second warning signal, with the first warning signal and its associated information being stored in the memory unit 26. Furthermore, the display unit 24 illuminates a yellow warning light due to the second warning signal. This indicates to the driver that they should visit a specialist workshop.

[0035] A third stage represents a significant exceedance of the limit values. In this case, the control unit 18 generates a third warning signal, which is stored with assignment information in the memory unit 26. Furthermore, due to the third warning signal, the display unit 24 shows a red warning light or a warning message on the display, requesting the vehicle 12 to stop.

[0036] The steering system can also be designed as a steer-by-wire system.

[0037] Furthermore, several sensors 22 can also be provided at different lateral areas near the front axle 14a and / or the rear axle 14b of the motor vehicle 12, each generating a second input signal and forwarding it to the evaluation unit 19.

[0038] Furthermore, instead of two measuring units 20a, 20b on each of the chassis axles 14a, 14b, only one measuring unit 20a, 20b could be provided on one chassis axle 14a, 14b, with the sensor 22 being located in the area of ​​the other chassis axle 14b, 14a to ensure spatial resolution of a lateral impact event. This could be the case, for example, if there is no rear axle steering, so that only one measuring unit 20a is located on the front axle 14a and the sensor 22 is located in the area of ​​the rear axle 14b.

[0039] In another embodiment, the storage unit 26 is integrated into the control unit 18.

[0040] The design of this system 10 ensures that direct and more precise detection of lateral impacts to the steering system on at least one chassis axle is possible. Furthermore, the location of potential damage to the steering system on chassis axles is more reliably determined by this system 10. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2 848 437 A1

[0004] DE 10 2004 021 550 A1

[0005] EP 0 778 461 B1

[0005]

Claims

[1] System (10) for detecting a lateral impact event at the steering on at least one chassis axle (14a, 14b) in a motor vehicle (12), comprising a steering system and a control unit (18) with an evaluation unit (19), wherein the steering system includes at least one electric motor (16a, 16b), wherein the electric motor (16a, 16b) is connected to the control unit (18) via a signal connection, wherein the evaluation unit (19) receives a first input signal which is compared with specified limit conditions, and wherein, if the limit conditions are exceeded, the control unit (18) generates a warning signal which is visualized to inform the driver of the motor vehicle (12), characterized by , that the first input signal is an electrical signal, in particular a voltage or current signal, wherein at least one measuring unit (20a, 20b) is provided which generates the electrical signal by measuring an induced current or induced voltage in the electric drive train. [2] System according to claim 1, characterized by , that a display unit (24) is provided which displays the warning signal via a warning message in the cockpit of the motor vehicle (12). [3] System according to any of the preceding claims, characterized by , that at least one sensor (22), in particular an accelerometer, is provided, and wherein the evaluation unit (19) receives a second input signal generated by the at least one sensor (22). [4] System according to claim 3, characterized by, that at least one sensor (22) is arranged in the area of ​​a chassis axle (14a, 14b) in such a way that it is possible to reliably assign damage to one chassis axle (14a, 14b). [5] System according to any of the preceding claims, characterized by that the boundary conditions are formed as a time interval and a signal peak. [6] System according to any of the preceding claims, characterized by , that the control unit (18) has a storage unit (26) wherein the warning signal is stored in the storage unit (26) with an assignment information, in particular a timestamp. [7] System according to any of the preceding claims, characterized by, that several electric motors (16a, 16b) are provided, wherein several first input signals are generated by several measuring units (20a, 20b), wherein the measuring units (20a, 20b) each generate the electrical signals by measuring the induced current or an induced voltage at each electric motor (16a, 16b) on different chassis axles (14a, 14b). [8] Method for detecting a lateral steering impact event on at least one axle in a motor vehicle with a system (10) according to one of the preceding claims comprising the following method steps: - Generating at least one first input signal by at least one measuring unit (20a, 20b) or generating at least one first and at least one second input signal; - Receiving the first input signal or the first and second input signals by the evaluation unit (19); - Comparison of the first input signal or the first and second input signals with the limit conditions by the evaluation unit (19); - Generating a warning signal when the limit conditions are exceeded by the control unit (18); - Illustrating the warning signal via a signal light or a warning message in the cockpit of the motor vehicle by the display unit (24). [9] Method according to claim 8, characterized by the additional procedural step: - Storing the warning signal with an assignment information in the storage unit (26) [10] Method according to claim 8 or 9, characterized by the additional procedural step: - Display of the warning signal after each restart of the vehicle

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