JP4664660B2 - Wheel vibration damping method and apparatus for vehicle wheels - Google Patents

Description

  The present invention relates to a wheel vibration damping method and apparatus for a vehicle wheel.

  Since modern vehicle drivetrains are optimized for weight and materials used, the connection between the engine and the wheels is always designed to be more flexible with respect to torsion. Thus, the drive system acts from a physical point of view with a wheel inertia moment, approximately like a torsion spring that provides an easily vibrated system with small damping. This mechanical design of the drive train makes vibrations more likely to occur within the speed process (ie, rotational speed) of the drive wheel.

  Furthermore, the vehicle engine support method may also make it easier to generate such wheel vibrations. Along with the drive shaft and its inherent moment of inertia, the engine acts as a vibrant system that is transmitted to the drive wheels and generates wheel vibrations.

  Wheel vibration is sensed by the driver and makes the driver uncomfortable. Furthermore, this vibration places an excessive load on the mechanical drive system components.

  An object of the present invention is to provide a method and apparatus capable of damping or eliminating such wheel vibration.

  According to the present invention, in a wheel vibration damping method for a vehicle wheel, a variable representing vibration is determined for at least one wheel in order to dampen the vibration, and the wheel brake of the wheel as a function of the determined variable. Is operated.

  According to the present invention, a wheel vibration damping device for a vehicle wheel includes a sensor device for measuring a variable representing vibration and a damping algorithm for generating a damping signal as a function of the measured variable. And a brake device for performing brake engagement as a function of the damping signal in at least one wheel.

  The essential idea of the present invention is to measure at least one variable representing the vibration and dampen the vibration by one (or more) short-time brake engagements that suppress the vibration. In this case, each brake engagement is shorter than the period of vibration. In addition, vibration damping essentially reduces the mechanical load on the drive train components.

  In this case, the important point is to provide the brake engagement in time so that the vibrations are damped and not even excited. Therefore, it is preferred that at least the vibration phase position is determined in order to be able to tune the brake engagement to the vibration phase position.

  The wheel speed is preferably measured by means of a rotational speed sensor and the respective desired vibration parameter, for example amplitude or phase position, is determined therefrom. The phase position of the vibration can be determined from the elapsed time from the occurrence of the last reversal point of vibration or the passage of the zero point in consideration of the period or frequency of vibration, for example.

  In addition to the phase position, at least one other vibration parameter, such as the amplitude of the vibration, is also preferably determined. Considering the vibration amplitude, the strength and time of the brake engagement can be adapted to the respective strength of the vibration. Thus, small vibrations can be suppressed by small brake pressure changes and large vibrations can be suppressed by larger brake pressure changes.

  In order to damp vibrations, it is preferred that a plurality of brake engagements are performed in succession for a short time. The brake engagement is preferably performed at the earliest every second cycle of vibration, because it waits for the effect of the previous brake engagement to appear and for the next brake engagement. This is because at least one period is always required in order to newly determine the vibration parameter that is changed by.

  According to a preferred embodiment of the invention, at least one vibration parameter, in particular the phase position, amplitude or period of the vibration, is determined by the measurement technique. The control device in which the damping algorithm is stored generates a damping signal, for example a damping pulse, as a function of one or more decision parameters, and the damping signal is transmitted to the brake device. The brake device translates the adjustment request into a corresponding brake engagement.

  In operating the brake device, it must be particularly taken into account that the brake device requires a certain response time in order to convert the control demand of the control device into a brake pressure change. This delay is based on known hydraulic brake devices, in particular on the activation of the hydraulic pump and the filling of the brake fluid into the brake. Therefore, the damping signal must be output a predetermined time before the point at which the brake exerts its damping action. This lead time should be considered correspondingly as a function of the device.

  The brake engagement according to the invention is preferably carried out for each wheel for each wheel. Brake engagement is performed synchronously on the two drive wheels, especially when multiple wheels vibrate in phase, as may occur in the vibrations described at the beginning of the two drive wheels coupled to the engine. It is preferred that In this case, the control device simultaneously outputs damping signals to the brake devices for the right and left drive wheels.

  A wheel vibration damping device in a vehicle wheel according to the invention comprises a sensor device for measuring at least one vibration parameter of wheel vibration and a brake as a function of measurement variables (eg vibration phase position, amplitude and / or period). A control device in which a damping algorithm for generating a damping signal by which the device is operated is stored, and a brake device for performing corresponding brake engagement by means of a wheel brake on at least one vibrating wheel.

The damping device according to the present invention preferably uses an existing brake device in the vehicle such as a hydraulic device of a travel dynamic characteristic control device (for example, ESP or ASR).
Furthermore, the damping device according to the invention is preferably configured such that the method steps described above can be performed.

  FIG. 1 shows a schematic view of a vehicle 1 having a damping device for damping wheel vibrations. The damping device essentially includes a control device (μC) 9 in which a damping algorithm is stored, a sensor device 8 (wheel sensors 8a and 8b) for measuring vibration variables in the drive wheels 2a and 2b, a wheel And brake devices 3, 10 (wheel brakes 3a, 3b; hydraulic device 10) that can be damped or eliminated by the brake engagement.

  In modern vehicles, the drive systems 4, 5, 7 (side shaft 4; drive shaft 5; differential gear unit 7) are often associated with the wheels 2a, 2b, often with the engine 6 together with the wheels 2a, 2b. Forms a vibration-prone system that causes vibration. That is, the wheel speeds (rotational speeds) of the wheels 2a and 2b are not constant, and vibrate around the average value MW as shown on the upper side of FIG. Here, the vibration of the wheel speed is represented by S. Such vibration particularly impairs the ride comfort, and further exerts an excessive load on the components of the mechanical drive system, particularly on the side shaft 4, the differential gear device 7 and the drive shaft 5.

  In order to damp the wheel vibration, first the vibration frequency or period T, amplitude A and / or phase position ψ of the vibration S is determined. Next, the control device 9 generates a damping pulse D as a function of the vibration parameter and outputs it to the brake devices 3 and 10. The damping pulse D (see FIG. 2) is finally converted into a corresponding increase in the brake pressure p by the brake devices 3 and 10. The damping pulse D is determined such that the desired damping action occurs with respect to time and magnitude.

  In order to determine the vibration parameters ψ, A, T, the damping device includes rotational speed (wheel) sensors 8a, 8b capable of determining the wheel speed or rotational speed n for each wheel. The sensor signal is supplied to the control device 9, which determines the desired vibration parameters.

The frequency or period T of the wheel vibration can be determined from, for example, the extreme values that follow the vibration S or the time difference between zero points.
The phase position ψ of the vibration S can be determined in consideration of the period T, for example, from the elapsed time since the last inversion point or the last zero point passage.

  Here, by knowing these vibration parameters, the brake engagement is performed by the wheel brake 3a or 3b so that the desired damping action (see brake pressure p in FIG. 2) is achieved in terms of time and magnitude. Is possible. As can be seen from FIG. 2, the brake pressure p acts essentially within the time frame in which the wheel vibration or vibration S exists above the mean value MW (ie in the positive half-wave of the wheel vibration). give.

Due to the final response time of the braking devices 3, 10, the damping pulse D is transmitted to the braking devices 3, 10 a predetermined time Δt before the braking action is started.
The damping signal is basically output to each wheel 2a, 2b independently of each other, and therefore the wheels 2a, 2b are damped for each wheel. Particularly in the same phase vibration of the wheels 2a and 2b generated for the drive shaft 5 and the engine 6 by the wheel vibration, the damping pulse D is simultaneously output to the left and right front drive wheels 2a and 2b, and therefore the wheel 2a. 2b are damped synchronously. Thereby, the damping action is improved as compared with asynchronous damping.

In the case of all-wheel drive vehicles, this method can correspondingly be used on the second drive axle as well.
The damping procedure is preferably performed only within a predetermined vibration frequency range.

  For example, in the control engagement of the travel dynamic characteristic control device such as ASR or ESP, the damping pulse D is preferably superimposed on the target brake torque output from the travel dynamic characteristic control device. The function of the wheel or vehicle stabilizer is maintained and the undesirable wheel vibration S is eliminated.

It is the schematic of the vehicle which has the damping device of the wheel vibration in a drive wheel. It is various signal diagrams important in damping of wheel vibration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Drive wheel 3 Wheel brake 4 Side shaft 5 Drive shaft 6 Engine 7 Differential gear device 8 Wheel sensor 9 Control device 10 Hydraulic device S Vibration MW Average value D Damping pulse p Wheel brake pressure T Period A Amplitude ψ Phase angle Δt delay time

Claims (9)

In order to damp the vibration (S), variables (ψ, A, T) representing the vibration (S) are determined for at least one wheel (2) and the determined variables (ψ, A, T) The wheel brake (3) of the wheel (2) is operated as a function of the wheel brake (3), the wheel brake (3) is operated several times before and after, and the wheel brake (3) is operated for the second or nth vibration (S). wheel vibration damping method of the wheels (2) of the vehicle (1), characterized in Rukoto only be operated for each cycle (T).   The wheel vibration damping method according to claim 1, characterized in that at least the phase position (ψ) of vibration (S) is determined and the wheel brake (3) is operated as a function of the phase position (ψ).   The wheel vibration damping method according to claim 1 or 2, characterized in that the amplitude (A) of the vibration (S) is determined and the wheel brake (3) is operated as a function of the amplitude (A).   4. The wheel vibration damping method according to claim 1, wherein the frequency or period (T) of the vibration (S) is determined. A control device (9) in which the vibration variables (ψ, A, T) are measured and the damping algorithm is stored generates a damping signal (D) as a function of the vibration variables (ψ, A, T) and is damped Signal transmission (D) is transmitted to the braking device (10, 3) and the brake engagement is performed as a function of the damping signal (D) in at least one predetermined wheel (2). 5. The wheel vibration damping method according to any one of 4 to 4 . The brake engagement, wheel vibration damping method according to any one of claims 1 to 5, characterized in that is performed for each wheel. When a plurality of wheels (2a, 2b) is oscillating in phase, in these wheels (2a, 2b), the brake engagement, claims 1, characterized in that it is executed in synchronism 5 The wheel vibration damping method according to any one of the above. 6. The wheel vibration damping according to claim 5 , wherein the damping signal (D) is transmitted to the braking device (10, 3) a predetermined time before the time when the brake engagement is to be performed. Method. Sensor devices (8, 9) for measuring variables (ψ, A, T) representing vibration (S);
A controller (9) having a damping algorithm for generating a damping signal (D) as a function of the measured variables (ψ, A, T);
Brake devices (3, 10) for performing brake engagement as a function of the damping signal (D) in at least one wheel (2);
With
The vehicle is characterized in that the wheel brake (3) is operated several times before and after, and the wheel brake (3) is operated only at the second or nth cycle (T) of vibration (S) ( Wheel vibration damping device for wheel (2) of 1).

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