DE102012217672A1 - Method for adjusting yaw damping on two-lane two-axle motor vehicle, involves creating single-track model or model diagram for explaining steady state and transient lateral dynamics of double-track vehicle by accessing model parameters - Google Patents

Abstract

The method involves generating an additional subduing yaw moment affecting a vehicle based on guidance request given by a driver during the course of varying yaw rate (r) of the vehicle. A measurement variable is reproduced by a controller by accounting input variables, speed (V) of the vehicle, predefined steering angle without feedback of yaw behavior of the vehicle. A single-track model (ESM) or model diagram for explaining steady state and transient lateral dynamics of double-track vehicle is created by accessing the model parameters. The damping yaw moment is represented by an actuator.

Description

The invention relates to a method for adjusting the yaw damping on a two-lane biaxial motor vehicle, wherein an additional acting on the vehicle damping yaw moment is generated on a predetermined by the driver steering request, which changes in the time course of the yaw rate of the vehicle caused by the steering request overshoot , especially reduced. The prior art is particularly to the EP 1 336 548 B1 and next to the DE 10 2005 037 479 A1 and on the WO 2006/007908 A1 directed.

For example, from the first-mentioned document, it is known that on a two-lane road vehicle, the yaw damping of the vehicle steering can be specifically and thereby changed in particular depending on the driving speed of the vehicle. As is known, a vehicle reacts to a driver's steering specification, with which, in particular, the steerable front wheels of the vehicle, possibly additionally the rear wheels of which are steered with a considerably smaller steering angle than the front wheels, d. H. be pivoted about its steering axis (Spreizachse), with a representable example as a time course of the yaw rate step response, which has a certain overshoot. This overshoot sounds in accordance with the vehicle's own yaw damping. This yaw damping, which is also known as vehicle-specific yaw damping, inherent in the vehicle, is inherent in the system and, in particular, dictated by the design of the chassis and by the overall design of the vehicle and continues to be dependent on the current boundary conditions.

To represent a desired driving behavior of the vehicle, which is noticeable to the driver when steering, the vehicle-specific yaw damping can be selectively changed by generating an additional yaw moment acting on the vehicle. This additional yaw moment is referred to herein as damping yaw moment. Such additional damping yaw moment may be at one in the already mentioned EP 1 336 548 B1 described regulated device for controlling the dynamic behavior of a vehicle by a controller having a setting function for the speed-dependent damping of the movement of the vehicle about a defined axis independently of the other properties of the vehicle about this defined axis. In this document, a corresponding controller is generally proposed for arbitrary axes (in space), the current determined by means of sensors information on vehicle dynamics are returned, so that in addition to the yaw damping with respect to a rotational movement about the vertical axis and pitching movements of the vehicle body ( around the Fzg.-transverse axis) and rolling movements of the vehicle body (about the vehicle longitudinal axis) can be attenuated accordingly.

It has been found that in the prior art according to the EP 1 336 548 B1 proposed interventions of a controller, in particular for the generation of an additional damping yaw moment can not be reliably reproduced represented or implemented. The expected or required by the controller driving dynamic feedback variables are often very noisy, sometimes come too late and are also dependent on the road and the environment, so with this known device desired by applying a damping yaw moment increase in ride comfort especially in the dynamic Linear range is not achievable. To point out a remedy for this problem is the object of the present invention.

The solution to this problem is for a method for adjusting the yaw damping according to the preamble of claim 1, characterized in that the (additional) damping yaw moment without returning a the yaw behavior of the vehicle reproducing measured variable is given by a controller, which as the only input variables, the driving speed of the vehicle and the driver's predetermined steering angle and further accesses the Einspurmodell or another model representation to explain the steady state and transient lateral dynamics of two-lane motor vehicles with the model parameters contained therein, and that this damping yaw moment is represented by a single suitable actuator.

According to the invention, a controller is used instead of a control, which manages without returning from the dynamics of the vehicle reproducing measured variables. This not only ensures a safe reproducibility, but it is advantageously an extremely fast, short-term response to a driver's guidance presented. The input variables considered in the context of the control are unambiguously unambiguous and are already available for use in other processes influencing vehicle dynamics. A quick influencing of the step response of the system to a steering input is also the further characteristic feature conducive that a single actuator is controlled in such a way that the desired damping yaw moment acts on the vehicle. For such an actuator different adjustment systems of the suspension actuators modern two-track vehicles come into question. In addition to a steering plate for the steerable front wheels (for example in the form of a superposition actuator on the steering column or steering shaft) may be a steering actuator for steerable rear wheels are used, but also actuators for one-sided influence on the vehicle longitudinal dynamics, ie by delaying only one wheel or wheels on a vehicle side or accelerated. Furthermore, the yaw momentum can also be influenced by an actuator influencing the vertical dynamics of the vehicle, so that a suitable damping yaw moment can be applied even with a vibration damper that is adjustable with respect to its damping characteristic or with one or one spring-rate or stabilizer adjustable in spring rate. Finally, an actuator for influencing the longitudinal force distribution between the front axle and the rear axle of the vehicle can be used, wherein the longitudinal forces can act in the form of train or thrust, that can accelerate or decelerate the vehicle. Using the common terminology, for example, an actuator of an "active steering" or a rear-wheel steering can be used, also actuators for wheel-individual brake intervention on the front axle or on the rear axle, or actuators for so-called. Torquevectoring or for roll stabilization, actuators of adjusting or one So-called Active BodyControl, furthermore a regulated rear axle lock or front axle lock or suitable actuators of a four-wheel drive system, which distribute the drive torque suitably between front axle and rear axle, as well as a functional all-wheel drive of two decoupled independently controllable axles and the torque vectoring by means of wheel hub motors, whereby these Enumeration is not exhaustive.

If the magnitude of the damping yaw moment to be generated is determined by factors stored in the controller which indicate the (for example percentage) relation to the vehicle-specific yaw damping, which system inherently acts without an additional damping yaw moment, a particularly simple system tuning on the vehicle is possible. An applicator, who interprets the control according to the invention for a vehicle or a vehicle type, can thus specify, in particular, as a function of the driving speed of the vehicle, by how many, ie. H. by what factor stronger (or weaker) than the vehicle-specific yaw damping should be effective with an implementation of the control according to the invention then actually on the vehicle yaw damping.

If in the daily driving experience the control according to the invention determines the stored specific factor on the basis of the current driving conditions, namely on the driving speed of the vehicle and on the driver's steering angle, then the vehicle-specific yaw damping acting under these boundary conditions must be known, so that a desired additional Steaming yaw moment can be made. Preferably, the said vehicle-specific yaw damping is calculated using the single-track model or based on another model representation to explain the stationary and transient lateral dynamics of two-lane motor vehicles, taking into account the necessary model parameters contained therein in an electronic control unit, wherein the said model parameters, for example, the skew stiffnesses of Front axle and the rear axle of the vehicle or sizes corresponding to these variables, namely the quotient of these skew stiffnesses and the so-called. Characteristic speed of the vehicle may continue to the vehicle speed, the current driver-specified steering angle, the vehicle mass and the position from its center of gravity or the inertia of the vehicle about the vertical axis. In this case, such model parameters can either be firmly applied or estimated in a basically known manner by means of a suitable observer model in one or the (mentioned) electronic control unit from the past behavior of the vehicle.

The controller according to the invention itself can work with different controller structures. Preference is given to a 1DOF structure or a PID controller or a regulated VS model or an inverse model precontrol. In this case, an actuator compensation known to the person skilled in the art can be carried out with regard to the best possible transmission behavior (of the actuator).

In terms of an advantageous development, provision may be made for various procedures for controlling a damping yaw moment according to the invention to be stored in or in a suitable electronic control unit, which lead to differently pronounced damping yaw moments. In this case, these various procedures can be selected by the electronic control unit itself depending on at least one further current boundary condition, or one of these various stored procedures can be selected by the driver of the vehicle. In particular, in the latter case, the relative strength of the set damping yaw moment can be communicated to the driver, in particular visually (via a suitable display). In this sense, thus an adaptation of the function according to the invention via a suitable control element, so for example. A so-called. Driving experience switch or a button for switching off an electronic Stabilization program or otherwise. In this case, the function according to the invention can be particularly pronounced in a driving mode which is fundamentally designed for high safety, ie produce a particularly high damping yaw moment, while in a "sportier" mode, in which an electronic stabilization program, for example, is essentially switched off, a relatively weak one (additional) yaw damping comes into effect. However, it is also an automatic adaptation of the function according to the invention with respect to the intensity of the yaw damping to current environment information, to which also "look ahead" information is possible, such environment information, for example, camera-based or radar-based or via a so-called "car2car communication", ie by exchanging information with other motor vehicles. Another example is a so-called evasion assistant, which recognizes an evasion situation and then adjusts the maximum possible yaw damping (in the sense of driving-situation-adaptive yaw damping).

δ_VA,ss

Vorderachs-Radlenkwinkel entsprechend einer Lenkwinkelvorgabe des Fahrers

δ_HA,ss

Hinterachs-Radlenkwinkel entsprechend einer Lenkwinkelvorgabe des Fahrers

v

Fahrgeschwindigkeit des Fahrzeugs

r_d

Wunschgierrate des Fahrzeugs

r

Gierrate des Fahrzeugs

ΔMz_d

Dämpf-Giermoment = (zusätzliches) Dämp-Giermoment

ΔMz_d,aktkomp

Dämpf-Giermoment mit Aktuatorkompensation hinsichtlich möglichst günstigem Übertragungsverhalten

PID

PID-Regler

ESM

Einspurmodell, mit welchem die weiter oben genannte fahrzeugspezifische Gierdämpfung ermittelt wird

Wunsch-ESM

Einspurmodell, welches unter der Verwendung der erfindungsgemäßen Steuerung oder Funktion die gewünschte Gierdämpfung und somit auch das gewünschte Dämpf-Giermoment enthält

The accompanying figures show two possible control structures, with which the function or control according to the invention for providing an additional damping yaw moment, which may otherwise be expressly negative, so that hereby the effective yaw damping compared to the vehicle-specific yaw damping can be reduced, can be represented , It shows 1 a structure with a PID controller and 2 a 1DOF structure. The letters and abbreviations contained in the figures stand for the following quantities or terms:

δ _{VA, ss}

Front axle wheel steering angle corresponding to a steering angle specification of the driver

δ _{HA, ss}

Rear axle wheel steering angle according to a steering angle specification of the driver

v

Driving speed of the vehicle

r _d

Desired yaw rate of the vehicle

r

Yaw rate of the vehicle

ΔMz _d

Damp yaw moment = (additional) damping yaw moment

ΔMz _{d, act}

Dampening yaw moment with actuator compensation for the best possible transmission behavior

PID

PID controller

ESM

Single-track model with which the above-mentioned vehicle-specific yaw damping is determined

Desire ESM

Single-track model, which contains the desired yaw damping and thus also the desired damping yaw moment using the control or function according to the invention

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• EP 1336548 B1 [0001, 0003, 0004]
• DE 102005037479 A1 [0001]
• WO 2006/007908 A1 [0001]

Claims (9)

Method for adjusting the yaw damping on a two-lane two-axle motor vehicle, wherein an additional damping yaw moment acting on the vehicle is generated in response to a steering request given by the driver, which changes over the time course of the yaw rate of the vehicle an overshoot caused by the steering request, in particular reduced, characterized in that the damping yaw moment is given by a controller without repatriation of the yaw behavior of the vehicle reproducible, which takes into account as the only input variables the driving speed of the vehicle and the driver specified steering angle and further to the Einspurmodell or another model representation to explain the stationary and transient transverse dynamics of two-lane motor vehicles with the model parameters contained therein accesses, and that this damping yaw moment is represented by means of a single suitable actuator. A method according to claim 1, characterized in that the magnitude of the damping yaw moment to be generated is determined by factors stored in the controller which indicate the (percentage) relation to the vehicle-specific yaw damping, which system inherently acts without an additional damping yaw moment. A method according to claim 2, characterized in that the vehicle-specific yaw damping is determined using the Einspurmodell or based on another model representation to explain the stationary and transient transverse dynamics of two-lane motor vehicles, taking into account the necessary model parameters contained in which model parameters are, for example, the skew stiffness of Front axle and rear axle of the vehicle, the vehicle speed, the current driver-specified steering angle, the vehicle mass and the position of its center of gravity or the inertia of the vehicle can act around the vertical axis. A method according to claim 1 or 2, characterized in that the controller operates with one of the following controller structures: • 1DOF structure • PID controller • regulated VS model • inverse model feedforward control Method according to one of the preceding claims, characterized in that the driver of the vehicle different procedures for the control of the damping yaw moment can be selected, which lead to different degrees of pronounced damping yaw moments. Method according to one of the preceding claims, characterized in that depending on other current boundary conditions different procedures for the control of the damping yaw moment are effective, leading to different degrees of pronounced damping yaw moments. The method of claim 5 or 6, wherein the driver, the relative strength of the set damping yaw moment is communicated visually in particular. Method according to one of the preceding claims, characterized in that one of the following actuators is used to set the damping yaw moment, namely an actuator for influencing the steering angle at front wheels or rear wheels, or for individual deceleration or acceleration of a wheel, or for influencing the vertical dynamics • for influencing the longitudinal force distribution between the front axle and the rear axle of the vehicle Method according to one of the preceding claims, characterized in that an actuator compensation is carried out with regard to the best possible transmission behavior.

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