System and procedure for processing data to stabilize a team

Abstract

System for processing data for stabilizing a vehicle combination comprising a trailer towed by a vehicle, comprising: - a device (1) for detecting trailer vibrations by acquiring and evaluating one or more measured variables (s1, ..., sn), which represent vehicle dynamics characteristics of the vehicle and / or the trailer,- a device (3) for determining a critical speed (vkrit) of the vehicle combination based on one or more detected trailer oscillations, characterized by- a device (2) for damping the oscillation of the vehicle combination based on driver-independent control interventions on one or more vehicle dynamics-influencing components (5) of the vehicle as a function of a quantity (SG) which represents the intensity of a swaying motion of the vehicle combination, wherein the determined critical speed (vkrit) is supplied to the device (2) for damping the oscillation of the vehicle combination for processing,- wherein the device for determining the critical speed (vkrit) is configured to use a phase and / or amplitude analysis to determine a phase delay between a first and a second vehicle dynamics parameter (s1, ...to establish , sn) of the vehicle and / or the trailer and to determine the critical speed (vcrit) from the phase delay.

Description

[0001] The invention relates to a system for processing data for stabilizing a vehicle combination consisting of a trailer towed by a vehicle. The system comprises a device for detecting trailer oscillations by acquiring and evaluating one or more measured variables that represent driving dynamics characteristics of the vehicle and / or the trailer. The system further comprises a device for damping the oscillation of the vehicle combination by means of driver-independent control interventions on one or more vehicle components that influence the vehicle dynamics, depending on a variable that represents the intensity of a swaying motion of the vehicle combination.

[0002] The invention further relates to a method for processing data to stabilize a vehicle combination comprising a trailer towed by a vehicle. In this method, trailer oscillations are detected by acquiring and evaluating one or more measured variables representing the vehicle dynamics of the vehicle and / or the trailer. In addition, oscillations of the vehicle combination and driver-independent control interventions on one or more vehicle components that influence the vehicle dynamics are dampened depending on a variable representing the intensity of the swaying motion of the vehicle combination.

[0003] In a vehicle combination, swaying movements can occur, e.g., due to crosswinds, in which the trailer swings around its vertical axis and, via the trailer coupling, also causes the towing vehicle to vibrate. Currently used approaches to stabilization The braking system for a vehicle combination aims to decelerate the combination as quickly as possible below a so-called critical speed. The critical speed depends on factors such as the vehicle combination's geometry, including wheelbase and drawbar length, the mass and yaw moment of inertia of both the vehicle and the trailer, and the axle lateral stiffness. For passenger car combinations, it typically ranges from 90 km / h to 130 km / h. In principle, the driver can achieve deceleration below the critical speed simply by applying the vehicle's brakes.

[0004] Automated systems detect critical trailer oscillations, for example, using sensors implemented in the vehicle and suitable detection algorithms in an ESP control unit (ESP = Electronic Stability Control), and automatically initiate corresponding activation of the wheel brakes. Braking and stabilization of the trailer can be achieved through symmetrical and asymmetrical braking intervention on the wheels of an axle. For example, the amplitude profile of the yaw rate and the driver's steering angle is used to detect the trailer's swaying motion.

[0005] When braking the vehicle combination, the temporary contact of the trailer with the towing vehicle generally leads to an initial increase in oscillation, since the critical speed at which the oscillation amplitudes increase is somewhat lower during deceleration than during towing or free-rolling operation. As a result, the vehicle must be braked quickly below the critical speed of the vehicle combination in order for the oscillation to subside. Particularly at medium and low road friction coefficients, the rebound of the oscillation can lead to critical driving conditions and, in the worst case, to the vehicle combination jackknifing. For example, particularly critical driving conditions can also arise if an inexperienced driver attempts to stabilize the unstable vehicle combination by steering.

[0006] The critical speed of a vehicle combination, i.e., the speed at which the combination begins to oscillate independently, is not specifically determined in current vehicles during operation due to the largely unknown and difficult-to-measure influencing parameters for oscillation sensitivity. This results in the disadvantage for the vehicle combination damping device that the control interventions required to stabilize the vehicle combination cannot be carried out to their full potential. In particular, there is a risk of erroneous interventions.

[0007] It is therefore an object of the present invention to provide a system and a method for processing data for stabilizing a vehicle combination, with which the driving safety of vehicle combinations can be increased.

[0008] These problems are solved by a system with the features of claim 1 and a method with the features of claim 14. Advantageous embodiments are described in the dependent claims.

[0009] In a generic system for processing data to stabilize a vehicle combination of the type described above, according to the invention a device for determining a critical speed of the vehicle combination on the basis of one or more detected trailer vibrations is provided, wherein the determined critical speed can be processed for controlling the damping of the vibration and / or can be displayed in the vehicle in a way that is perceptible to a driver.

[0010] In a generic method of the type described above, a critical speed of the vehicle combination is determined according to the invention on the basis of one or more detected trailer vibrations, wherein the determined critical speed is processed to control the damping of the vibration and / or is displayed in the vehicle in a way that is perceptible to a driver.

[0011] The invention is based on the principle of continuously and approximately determining the critical speed during driving, in order to then process this information for controlling the damping of the vibration and / or to make it perceptible to the driver. In particular, this makes it possible to inform the driver of the maximum speed at which the vehicle combination may be driven. Furthermore, the control of the damping of the vehicle combination's vibration can be carried out in a much more targeted manner than is possible in the prior art. In methods known from the prior art, the critical speed is merely a theoretical and often unknown quantity, which must be undercut by corresponding control interventions in order to keep the vehicle combination stable.

[0012] In contrast, the invention provides for processing the critical speed within the framework of the control of the damping of the oscillation of the vehicle combination and thus influencing the type and / or intensity of the control. By including the critical speed in a system for processing data for stabilizing a vehicle combination, it is possible to better counteract stability-critical driving situations resulting from oscillations about the vertical axes of the vehicle combination. With the invention, corrective damping measures can be implemented more precisely.

[0013] According to one embodiment of the system according to the invention, the component influencing the vehicle dynamics is a braking system and / or a vehicle management system and / or a steering system and / or a torque distribution system of the vehicle. The braking system can, for example, perform a driver-independent symmetrical or asymmetrical braking intervention, which is carried out in the correct phase relative to the stability-critical oscillation. The vehicle management system includes, for example, reducing engine power or using the electronics employed for an electronic stability program to selectively brake or, if necessary, accelerate individual wheels. The steering system can perform a temporary intervention in the vehicle's steering. This allows corrective steering movements to be initiated or unfavorable steering movements to be avoided. The intervention can be passive, i.e., without a steering movement intended by the driver.It is also possible to make it more difficult for the driver to make incorrect steering movements, or to provide a steering recommendation, the observance of which is left to the driver's discretion. Active intervention in the steering, in the form of an actual steering movement, is also possible.

[0014] Another embodiment provides that the device for determining the critical speed is designed to analyze the vibrations of the trailer with regard to the temporal evolution of the amplitudes. In particular, it can be provided that the device for determining the critical speed is designed to determine a damping coefficient for the vibration in order to determine the critical speed from this. The critical speed can be determined, for example, by analyzing the pendulum movements and based on the decaying amplitude. Here, vibration analysis is used to determine the damping coefficient at which the amplitudes of the vibration increase or cease to decay. From this, the critical speed can be determined.

[0015] In particular, the device for determining the critical speed is designed to determine a stability criterion that represents a measure of the stability of the vehicle combination. For this purpose, for example, Lehr's damping coefficient, which represents a damping factor, can be determined. If the damping coefficient is less than zero, the vehicle combination is unstable and may sway. This means that if a vibration excitation occurs, such as a crosswind, the stability of the vehicle combination may no longer be restored. A damping factor of zero indicates a quasi-stable vehicle combination. This means that the critical speed value is reached at this value. If the damping factor is greater than zero, the vehicle combination is stable or self-stabilizing, so that no control interventions are meaningful in this range, even if the device for detecting trailer vibrations has detected a vibration of the vehicle combination.

[0016] According to a further embodiment, the device for determining the critical speed is designed to establish a phase shift between a first and a second vehicle dynamics parameter of the vehicle and / or the trailer by means of a phase and / or amplitude analysis and to determine the critical speed from the phase shift. This phase shift can be determined, for example, by a cross-correlation between the first and the second vehicle dynamics parameter. The first vehicle dynamics parameter is, for example, a lateral acceleration, while the second vehicle dynamics parameter is a yaw rate, in particular of the vehicle.

[0017] Another preferred embodiment of the system according to the invention provides that the device for damping the vibration is activated above the determined critical speed. Conversely, this means that control for damping the vibration below the determined critical speed is not provided, or at least not necessarily provided, since, based on the knowledge of the critical speed, a self-stabilizing system has been recognized. In particular, it can be provided that below a threshold speed, which is a predetermined value below the critical speed, no damping control takes place, while between the threshold speed and the critical speed, damping is controlled.

[0018] According to a further preferred embodiment, the vibration damping device is designed such that the damping intensity is adjusted depending on the ratio of the critical speed to a determined (actual) speed value of the vehicle combination. Based on the knowledge of the critical speed, the system is able to recognize how quickly and / or how aggressively the vibration damping must occur. In particular, rapid and aggressive damping is necessary when the vehicle combination is traveling at a speed above the critical speed. If vibration damping also occurs at a speed value below the critical speed, the degree of damping can be adjusted depending on how close the actual speed of the vehicle combination is to the critical speed.

[0019] In a further embodiment, an optical and / or acoustic and / or haptic output device is provided for the perceptible indication of the critical speed. The critical speed can be visually indicated to the driver, for example, by a light or display in the instrument cluster or in another display, e.g., a human-machine interface (HMI). Likewise, reaching or exceeding the critical speed can be signaled acoustically by a tone or sequence of tones emitted through the vehicle's speakers. A haptic indication of reaching the critical speed can be achieved, for example, by a vibration in the steering wheel, a vibration of the seat, and the like.

[0020] It is further advantageous to provide a memory for storing the critical speed for controlling the damping of the oscillation of the vehicle combination. This means that the critical speed of the vehicle combination only needs to be determined once, and can then be read from the memory for further processing to control the damping of the oscillation of the vehicle combination. In addition to the advantages mentioned above, this also enables shorter response times for the damping device, since the time-consuming calculation of the oscillation can be eliminated.

[0021] For reasons of vehicle safety, it is also advantageous for the system to be designed to recalculate the critical speed after a clamp change and / or when the vehicle has come to a standstill. This is beneficial because the critical speed depends on a multitude of factors, such as the moment of inertia of the trailer, the vertical load, the type and mass of the load, the drawbar length, and the like. When a clamp change and / or the vehicle comes to a standstill, it is therefore assumed that at least one of the aforementioned parameters may have changed. Since this could affect the critical speed, it is therefore provided that the critical speed is recalculated after each clamp change, e.g., when the vehicle is parked, in order to make maximum use of the potential of the vehicle-trailer stabilization.

[0022] To facilitate the determination and ascertainment of the critical velocity, it may also be provided that the originally determined value of the critical velocity is processed as a starting point for the re-determination of the critical velocity.

[0023] The invention is explained in more detail below with reference to an exemplary embodiment. The single figure shows a schematic representation of a system for processing data for stabilizing a vehicle combination.

[0024] The system according to the invention for processing data to stabilize a vehicle combination consisting of a trailer towed by a vehicle comprises a device 1 for detecting trailer vibrations. Trailer vibrations are detected by acquiring and evaluating one or more measured variables s1 ... sn, which represent vehicle dynamic parameters of the vehicle and / or the trailer. Such vehicle dynamic parameters can be, for example, the lateral acceleration of the vehicle and / or the trailer, the wheel speed of the vehicle and / or the trailer, the articulation angle between the vehicle and the trailer, the articulation angle velocity, the steering angle, and the yaw rate or velocity of the vehicle and / or the trailer.

[0025] The system further comprises a device 2 for damping the oscillation of the vehicle combination by means of driver-independent control interventions on one or more components influencing vehicle dynamics, depending on a control variable SG, which represents the intensity of the swaying motion of the vehicle combination. The control variable SG is determined by the device 1 from the measured variables s1 ... sn. The components influencing vehicle dynamics, which are identified by reference numeral 5, can be a braking system and / or a vehicle management system and / or steering systems and / or a torque distribution system of the vehicle, each of which can be controlled independently of the driver. In particular, the components 5 influencing vehicle dynamics include components that are already used to implement an electronic stability program (ESP) of the vehicle.The corresponding components 5 influencing vehicle dynamics receive a corresponding control signal StS from the device 2 for damping the vibration of the vehicle combination.

[0026] Furthermore, the system includes a device 3 for determining a critical speed vkrit of the vehicle combination based on one or more detected trailer vibrations. For this purpose, the device 3 for determining the critical speed optionally receives a signal AS determined by the device 1 for detecting trailer vibrations or directly one or more of the measured variables s1 ... sn. The determined critical speed vkrit is processed to control the damping of the vibration and accordingly supplied to the device 2. Alternatively or additionally, the critical speed vkrit can be communicated to the driver via an output device 4 in the vehicle.

[0027] The output device 4 can be optical, acoustic, and / or haptic. The critical speed can be visually indicated to the driver, for example, by a light or display in the instrument cluster or another display, such as a human-machine interface (HMI). Likewise, reaching or exceeding the critical speed can be signaled acoustically by a tone or sequence of tones emitted through the vehicle's loudspeakers. Haptic feedback indicating that the critical speed has been reached can be achieved, for example, by a vibration in the steering wheel, a vibration in the seat, and the like. The output device 4 enables the driver to recognize at what speed a critical situation for the vehicle combination could arise.

[0028] Furthermore, the system can include a memory (not shown) in which the determined critical speed value vcrit is written after its determination. This means that the critical speed value vcrit only needs to be determined once, at least between two terminal changes and / or vehicle standstills, and can be used for further processing by the device 2 or the output device 4. After a terminal change or a recorded standstill of the vehicle, it is advantageous to determine the critical speed again. In these situations, it must be taken into account that, for example, the trailer The critical speed (vcrit) could be determined if the trailer was detached from the vehicle (this can be determined by checking the occupancy of the trailer hitch socket) or if, for example, the trailer's load was changed. In contrast, it is not possible to load the trailer or change its behavior while driving, so repeated determination of the critical speed (vcrit) is not necessary during a journey of the vehicle combination.

[0029] A continuous, approximate determination of the critical speed vcrit during driving leads to a better result, since the evaluation of as many pendulum oscillations as possible is required for the accurate determination of the critical speed vcrit. The determination of the critical speed can be carried out, for example, by analyzing the pendulum movements of the vehicle combination. For this purpose, in particular, an articulation angle between the vehicle and the trailer, the articulation angle velocity, optionally a steering angle of the vehicle, and lateral accelerations of the vehicle must be taken into account. Based on the oscillating amplitudes, the Lehr damping coefficient can be determined. The Lehr damping coefficient (damping factor D) is an energy quantity for the damping of an oscillation. For a damped harmonic oscillation, the damping factor D is defined as where: D: Damping level, d: Damping constant, k: spring constant, m: Mass, 0: Natural angular frequency.

[0030] The damping coefficient D is dimensionless and describes the oscillatory behavior of a physical system. It is directly related to the so-called logarithmic decrement ΔL via the equation:

[0031] The logarithmic decrement is a measure of the damping behavior in freely oscillating, decaying vibration systems. It is calculated from the natural logarithm of the ratio of the amplitudes of two successive deflections in the same direction: where: xm: Amplitude of the first deflection, xn: Amplitude of the second deflection, &dgr;: Damping level, 0: Natural frequency of the undamped oscillation, T: Oscillation period.

[0032] Alternatively, &Lgr; can also be calculated as follows:

[0033] Determining the logarithmic decrement is very easy to do by practically measuring the amplitude. The damping coefficient can then be determined from this.

[0034] With a damping coefficient D < 0, the vehicle combination is prone to swaying; that is, if a disturbance occurs, such as a crosswind, instability of the vehicle combination is to be expected, leading to a critical driving situation. With a damping coefficient D = 0, the vehicle combination is quasi-stable, in which the amplitudes of the oscillations remain constant. This means that the critical speed vcrit has been reached. In contrast, with a damping coefficient D > 0, the vehicle combination is stable or self-stabilizing, and no intervention is advisable. If necessary, it is advantageous to use a slightly lower value, e.g., vcrit – 10 km / h, as the limit for controlling the damping of the oscillation, rather than the critical speed vcrit itself.

[0035] Alternatively, the critical speed can also be determined by phase and / or amplitude analysis. Here, a phase shift is established between two vehicle dynamics parameters of the vehicle and / or the trailer, from which the critical speed vcrit can then be determined. It is advantageous to use the lateral acceleration and yaw rate, particularly of the vehicle, as the first and second vehicle dynamics parameters. The phase shift can be determined, for example, by cross-correlation of the two vehicle dynamics parameters.

[0036] The system and method according to the invention enable an improvement in the performance of trailer stabilization systems and, in particular, a significant increase in robustness against erroneous interventions. Currently known trailer stabilization systems do not determine the critical speed or only determine it relatively inaccurately, and, in particular, do not store it, so that the critical speed has to be relearned repeatedly. In contrast, the invention makes it possible to control the damping of the vibration in a way that is adapted to the actual situation. More targeted interventions of the trailer stabilization system are possible because the critical point for the trailer, namely reaching or exceeding the critical speed, is known.

[0037] As a result, road safety is increased because the driver is also informed about the critical speed. This allows the driver to actively contribute to avoiding critical driving situations caused by instability of the vehicle combination by reducing speed.

[0038] A further advantage of the invention is that trailer stabilization can be implemented in a very simple and cost-effective manner, since the determination of the critical speed can be achieved by modifying the software in the trailer stabilization logic, which is based on the ESP. Furthermore, no additional hardware components are necessary that are subject to wear and tear or incur costs. Reference symbol list 1 Device for detecting trailer vibrations 2 Device for damping the vibration 3 Device for determining the critical velocity 4 Output device 5 Component influencing vehicle dynamics s1 driving dynamics parameter sn driving dynamics parameter AS signal SG Quantity representing the intensity of the wobbling movement StS Control signal vkrit critical speed

Claims

[1] System for processing data to stabilize a vehicle combination comprising: – a device (1 ) for detecting trailer vibrations by recording and evaluating one or more measured variables (s1, ..., sn) which represent vehicle dynamic properties of the vehicle and / or the trailer, – a device (2 ) for damping the oscillation of the vehicle combination by means of driver-independent control interventions on one or more components (5 ) of the vehicle that influence the vehicle dynamics as a function of a quantity (SG) which represents the intensity of a swaying motion of the vehicle combination, characterized by the fact that – a device (3) for determining a critical speed (vkrit) of the vehicle combination based on one or more detected trailer vibrations is provided, wherein the determined critical speed (vkrit) can be processed for controlling the damping of the vibration and / or can be displayed in the vehicle in a way that is perceptible to a driver. [2] System according to claim 1, characterized in that the component influencing the vehicle dynamics (5 ) is a braking system and / or a vehicle management system and / or a steering system and / or a torque distribution system of the vehicle. [3] System according to claim 1 or 2, characterized in that the device (3 ) for determining the critical velocity (vkrit) is designed to analyze the vibrations of the trailer with respect to the temporal course of the amplitudes. [4] System according to claim 3, characterized in that the device (3 ) for determining the critical velocity (vkrit) is configured to determine a damping factor for the vibration in order to determine the critical velocity (vkrit) from this. [5] System according to claim 3 or 4, characterized in that the device (3 ) for determining the critical speed (vcrit) is configured to determine a stability criterion that represents a measure of the stability of the vehicle combination. [6] System according to claim 1 or 2, characterized in that the device for determining the critical speed (vkrit) is designed to create a phase delay between a first and a second vehicle dynamics parameter (s1, ..., sn) of the vehicle and / or the trailer by means of a phase and / or amplitude analysis and to determine the critical speed (vkrit) from the phase delay. [7] System according to claim 6, characterized in that the first vehicle dynamics parameter is a lateral acceleration and the second vehicle dynamics parameter is a yaw rate, in particular of the vehicle. [8] System according to one of the preceding claims, characterized in that activation of the device (2) for damping the vibration above the determined critical velocity (vcrit) is provided. [9] System according to one of the preceding claims, characterized in that the device (2 ) for damping the vibration is designed such that the intensity of the damping is adjusted as a function of the relation of the critical velocity (vcrit) to a determined velocity value of the vehicle combination. [10] System according to one of the preceding claims, characterized in that an optical and / or acoustic and / or a haptic output device (4) is provided for the perceptible representation of the critical velocity (vcrit). [11] System according to one of the preceding claims, characterized in that a memory is provided for storing the critical velocity (vkrit) for controlling the damping of the vibration of the vehicle combination. [12] System according to one of the preceding claims, characterized in that it is configured to redetermine the critical speed (vkrit) after a terminal change or a detected vehicle position. [13] System according to claim 12, characterized in that, for redetermining the critical speed (vkrit), the originally determined value is processed as the starting point for the determination. [13] Methods for processing data to stabilize a vehicle combination consisting of a trailer towed by a vehicle, both: – Trailer vibrations are detected by recording and evaluating one or more measured variables that represent the driving dynamics characteristics of the vehicle and / or the trailer; – dampening of the vehicle combination by means of driver-independent control interventions on one or more vehicle components influencing vehicle dynamics, depending on a quantity that represents the intensity of a swaying motion of the vehicle combination. characterized by the further step that – a critical speed (vkrit) of the vehicle combination is determined based on one or more detected trailer vibrations, whereby the determined critical speed (vkrit) is processed to control the damping of the vibration and / or is displayed in the vehicle in a way that is perceptible to a driver.

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