JPH05178046A - Active dynamic vibration absorber for vehicles - Google Patents

Abstract

PURPOSE:To provide a vehicle with an active dynamic vibration absorber which can be controlled with high stability. CONSTITUTION:The rotational frequency N of an engine is detected by an engine rotational frequency sensor 25. The vertical acceleration d<2>X1/dt<2> of a car body floor is detected by an acceleration sensor 26. A controller 27 performs condition feed-back control based on the vertical acceleration d<2>X1/dt<2> to determine a controlling force (u) of an active dynamic vibration absorber 1 and output control current I while setting the feed-back gain of the condition feed-back control on the basis of the engine rotational frequency N.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active dynamic vibration damper for a vehicle, which reduces vibration generated in a vehicle body.

[0002]

2. Description of the Related Art As conventional techniques of this kind, for example,
There is one disclosed in FIG. 4 of Japanese Utility Model Laid-Open No. 60-88137. This conventional active dynamic vibration absorber has a mass body that is elastically supported with respect to the vehicle body, and an actuator including a magnet fixed to the mass body side and an electromagnetic coil fixed to the vehicle body side. Vehicle vibration is absorbed by the force applied to the vehicle body by the supported mass body and the electromagnetic force generated between the actuator body and the mass body.

[0003]

However, in the above-mentioned conventional active dynamic vibration reducer, the sine wave whose phase is converted based on the detected value is detected by detecting the secondary component of the engine rotation during idling. Since the actuator is driven as, there is no guarantee of stability with respect to the absolute value (magnitude) of the control signal, and if an attempt is made to adjust the absolute value of the control signal by feedback control, for example, the load on the controller is large and the cost increases significantly It will be accompanied by an increase. Further, the phase control cannot cope with a transitional change, so that there is a problem that the control response may be low.

The present invention has been made by paying attention to the unsolved problems of the prior art as described above, and is capable of executing highly stable control without causing a significant increase in cost. The purpose of the present invention is to provide an active dynamic vibration reducer.

[0005]

In order to achieve the above object, the invention according to claim 1 is for a vehicle provided with a mass body elastically supported with respect to a vehicle body and an actuator for applying a force to the mass body. In an active dynamic vibration reducer, an engine speed detection unit that detects an engine speed of the vehicle, a vehicle body vibration state detection unit that detects a vehicle body vibration state of the vehicle, and feedback control based on the vehicle body vibration state are executed. Then, a control means for outputting a control signal to the actuator and a feedback gain setting means for setting a feedback gain of the control means according to the engine speed are provided.

According to a second aspect of the present invention, in the first aspect of the present invention, the vehicle body vibration state detecting means detects the displacement and speed of vibration as the vehicle body vibration state, and the feedback gain setting means sets the engine rotation speed. It has a mode determination means for determining whether the vehicle body vibration is in the low frequency mode or the high frequency mode based on the number, and when the mode determination means determines that it is in the low frequency mode, the displacement of the vibration is detected. A feedback gain that puts a weight is set, and when it is determined that the high frequency mode is set, a feedback gain that puts a weight on the speed of the vibration is set.

[0007]

When the vibration state of the vehicle body is detected by the vehicle body vibration state detecting means, the control means executes feedback control based on the vehicle body vibration state and outputs a control signal to the actuator. Unlike the phase control, stable control is executed without constructing a particularly complicated control device.

Since the feedback gain setting means sets the feedback gain of the feedback control executed by the control means in accordance with the rotation speed of the engine which is the vibration source, the stability of the control can be achieved also by this. .. Particularly, in the invention of claim 2,
Based on the engine speed, the mode determination means determines whether the vehicle body vibration mode is the low frequency mode or the high frequency mode, and when it is determined to be the low frequency mode, it is detected as the vehicle body vibration state. If a feedback gain that puts weight on the displacement of vibration is set and it is determined that the high frequency mode is set, a feedback gain that puts weight on the speed of vibration detected as the vehicle body vibration state is set. A feedback gain suitable for the mode will be set.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a model diagram showing an entire system to which an active dynamic vibration absorber 1 for a vehicle according to the present invention is applied.
FIG. 3 is a sectional view showing a configuration example of an active dynamic vibration reducer 1. First, the structure will be described. This active dynamic vibration reducer 1 is shown in FIG.
As shown in FIG. 1, the cylindrical housing 2 is provided, and the shaft 3 has a shaft 3 at the axial center of the cylindrical housing 2.
Are supported by linear bearings 11A and 11B so as to be movable back and forth in the axial direction.

A mass body 4 made of a magnetic material is fixed to the shaft 3, and the mass body 4 has a cylindrical main body 4a coaxial with the shaft 3 and a shaft 3 at the upper end of the main body 4a. It is composed of a flange portion 4b formed coaxially. A ring-shaped permanent magnet 5 is fixed to the surface of the mass body 4 facing the lower side of the flange portion 4b coaxially with the shaft 3, and the lower surface side of the permanent magnet 5 is made of a magnetic material. The ring member 6 is fixed coaxially with the shaft 3. However, mass 4
Between the peripheral surface of the main body 4a and the inner peripheral surface of the ring member 6,
There is a gap.

The permanent magnet 5 is a magnet having poles in the axial direction. Therefore, the magnetic flux generated by the permanent magnet 5 is applied to the peripheral surface of the main body 4a of the mass body 4 and the inner peripheral surface of the ring member 6. The clearance between the surfaces faces the direction perpendicular to the axis 3 at any position in the circumferential direction. on the other hand,
On the inner end surface of the housing 2 on the side where the ring member 6 faces, a cylindrical bobbin 9 coaxial with the shaft 3 is provided so as to surround the body 4a of the mass body 4 without contacting either the body 4a or the ring member 6. Is fixed.

The bobbin 9 has a body 4 of the mass body 4.
An electromagnetic coil 10 is wound coaxially with the shaft 3 so as to be located in a gap between the peripheral surface of a and the inner peripheral surface of the ring member 6, and a signal line 16 is provided to the electromagnetic coil 10 through the signal wire 16. Thus, a control current of arbitrary magnitude can be supplied from outside in any direction. Although the ring member 6 and the electromagnetic coil 10 are not in contact with each other, it is desirable that the gap be small in order to efficiently generate the electromagnetic force. Therefore, the linear bearings 11A, 11B, etc. are used. Clearance management is required.

Here, in this embodiment, the permanent magnet 5 and the electromagnetic coil 10 constitute an actuator that generates an electromagnetic force in the axial direction of the shaft 3. Further, between the upper surface of the flange portion 4b of the mass body 4 and the inner end surface of the housing 2 that faces the flange portion 4b, a coil spring 7 that applies an elastic force in the axial direction of the shaft 3 is interposed, and the ring member 6 A coil spring 8 that also applies an elastic force in the axial direction of the shaft 3 is interposed between the lower surface and the inner end surface of the housing 2 that faces the lower surface.
It is elastically supported by.

The active dynamic vibration absorber 1 is fixed to a vehicle body 20 as a vibration control target via bolts 21 so that the vibration direction of the vehicle body 20 and the axial direction of the shaft 3 coincide with each other. To use. Further, as shown in FIG. 1, an engine speed sensor 25 as an engine speed detecting means for detecting an engine speed N and a vehicle body vibration state for detecting a vertical acceleration d ² x ₁ / dt ² of a driver's floor. The acceleration sensor 26 as a detection means, the engine speed N and the vertical acceleration d ² x ₁ / dt ²
Based on the above, the controller 2 that executes a predetermined process to supply the control current I to the electromagnetic coil 10 of the active dynamic vibration absorber 1
7 and are provided.

Next, the operation of this embodiment will be described. Here, the vibration when the vehicle is idling is 20 in the frequency domain.
Corresponding to ~ 30Hz, in the vehicle body in the normal vehicle state,
There are two to three problematic vehicle body vibration modes. In the idle vibration, these vibration modes are excited to increase the vibration level. Therefore, if the problematic vibration mode is suppressed, the idle vibration is reduced as a whole.

Therefore, as shown in FIG. 3, taking a case in which there is a mode of two-body bending at 20 Hz and a mode of front bending at 30 Hz as an example, the idle speed is 750 rpm or less (engine rotation 2 Next frequency is 25
In the case of (Hz or less), it is desirable to execute the feedback control suitable for reducing the vibration of the second bending of the vehicle body, and conversely, the idle rotation speed exceeds 750 rpm (the engine rotation secondary frequency exceeds 25 Hz). in case of,
It is desirable to execute feedback control suitable for reducing the vibration of the front bending of the vehicle body.

FIG. 4 shows a case where such an example is targeted.
Flow chart showing an outline of the processing executed in the controller 27.
-It is a chart. That is, in the controller 27, first
In the step, read the engine speed N, then
Then, the process proceeds to step and the engine speed N is 750
It is determined whether or not it is rpm or less. And 750r
pm or less (engine rotation secondary frequency is 25 Hz or less
If below), go to step and give feedback
Gain f₁, F₂, F₃, F_FourFor low frequency mode
Feedback gain f₁₁, F _{twenty one}, F₃₁, F₄₁Set to
Over 750 rpm (engine rotation secondary frequency is 25
If the frequency exceeds (Hz), move to the step and
Feedback gain f₁, F₂, F₃, F_FourHigh frequency mode
Feedback gain f₁₂, F_{twenty two}, F ₃₂, F₄₂
Set to.

These feedback gains f ₁₁ to
If f ₄₁ and f _{12 to} f ₄₂ are obtained by the optimal regulator theory, stable gains are required for each vibration mode. Then, the process moves from step to step, the vertical acceleration d ² x ₁ / dt ² is read, the process moves to step, and the vertical speed dx ₁ / d
Calculate t and vertical displacement x ₁ .

Then, the process proceeds to step, and based on the vertical acceleration d ² x ₁ / dt ² , the vertical displacement x ₂ and vertical velocity dx ₂ / of the mass body 4 in the active dynamic vibration absorber 1 is increased.
Estimate dt. The vertical displacement x ₂ and the vertical velocity dx ₂ / dt can be actually measured by separately providing a detection device or the like, but in the present embodiment, they are obtained by estimation in order to reduce costs. I am trying.

Then, the process proceeds to step, and the control force u is determined based on the following equation (1), and u = f ₁ × dx ₁ / dt + f ₂ × dx ₂ / dt + f ₃ × x ₁ + f ₄ × x ₂ ... (1) The control current I is supplied to the electromagnetic coil 10 so that the control force u is generated as an electromagnetic force between the permanent magnet 5 and the electromagnetic coil 10 in the step (1).

When the control current I is supplied to the electromagnetic coil 10, an electromagnetic force is generated between the permanent magnet 5 and the electromagnetic coil 10, so that a force is applied between the mass body 4 and the housing 2,
This force is transmitted to the vehicle body 20 together with the force generated by the mass spring system composed of the mass body 4, the permanent magnet 5, the ring member 6 and the coil springs 8 and 9, and the vibration of the vehicle body 20 is reduced.

5 and 6 are characteristic diagrams showing the damping effect when the active dynamic vibration absorber 1 controls the one-degree-of-freedom system. FIG. 5 shows that the displacement of the controlled vibration is weighted. Fig. 6 shows the damping effect when the placed feedback gain is set.
Shows the damping effect when a feedback gain is set with weight on the speed of vibration. That is, when the displacement is weighted, a good vibration damping effect is obtained in the region near the peak frequency, but there is almost no vibration damping effect in the high frequency region, and when the velocity is weighted, the peak frequency is slightly higher. The vibration becomes worse on the low frequency side, but on the high frequency side, the damping effect can be obtained in a wide band.

Therefore, in the step, the feedback gains f _{1 to} f ₄ are set so that the feedback gains f ₃ and f ₄ are weighted, and in the step, the feedback gains f ₁ and f ₂ are weighted. setting the feedback gain f ₁ ~f _4. And
The effect when the control is performed in consideration of both the vibration modes of 20 Hz and 30 Hz is shown in the characteristic A of FIG.
For comparison with this, characteristic B shows the damping effect when only the vibration mode of 20 Hz is considered.

According to this, in the characteristic B, 30H
There is no vibration reduction effect near z, but in the characteristic A,
It can be seen that a good vibration damping effect is obtained in both the frequency regions near 20 Hz and around 30 Hz. in this way,
In this embodiment, the feedback gains f _{1 to} f ₄ are set appropriately according to the frequency of the idle vibration, and the vibration speed dx ₁ obtained as the vibration state of the vehicle body 20 is set.
/ Dt and displacement x ₁ , and vertical velocity dx of mass body 4
₂ / dt and the vertical displacement x ₂ are fed back to determine the control force u by the state feedback, and the control current I
Is output, the control is highly stable, and
A good vibration damping effect can be obtained in a wide frequency band during idling.

Further, unlike the phase conversion control which has been performed conventionally, the controller 27 only needs to execute a very simple arithmetic process, so that the configuration of the controller 27 itself can be simple and the cost can be reduced. If the content of the arithmetic processing is simple, the processing can be speeded up and a transient change can be dealt with quickly. Here, in the present embodiment, the acceleration sensor 26 and steps to.
The processing in (1) constitutes the vehicle body vibration state detection means, the processing in steps (1) and (2) constitutes the control means, the processing in steps (1) to (3) constitutes the feedback gain setting means, and the steps constitute the mode determination means.

[0026]

As described above, according to the present invention,
Since the feedback control based on the vibration state of the vehicle body is executed and the feedback gain of the feedback control is set according to the engine speed, control with excellent stability and responsiveness can be performed, and the controller is simple. The structure has the effect of reducing the cost, and in particular, the invention according to claim 2 has the effect of obtaining a good vibration damping effect in a wide frequency band.

[Brief description of drawings]

FIG. 1 is a model diagram showing a system configuration of an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration example of an active dynamic vibration reducer.

FIG. 3 is a characteristic diagram showing a relationship between a frequency and a vibration state of a vehicle body.

FIG. 4 is a flowchart showing an outline of processing executed in a controller.

FIG. 5 is a characteristic diagram showing a vibration damping effect when a weight is placed on a vibration displacement.

FIG. 6 is a characteristic diagram showing a vibration damping effect when a weight is placed on a vibration speed.

[Explanation of symbols]

 1 Active Dynamic Vibration Absorber 4 Mass Body 5 Permanent Magnet 7, 8 Coil Spring 10 Electromagnetic Coil 20 Car Body 25 Engine Speed Sensor 26 Acceleration Sensor 27 Controller

Claims (2)

[Claims] 1. An active dynamic vibration absorber for a vehicle, comprising: a mass body elastically supported with respect to a vehicle body; and an actuator for applying a force to the mass body, wherein an engine speed detection for detecting an engine speed of the vehicle. Means, vehicle body vibration state detection means for detecting a vehicle body vibration state of the vehicle, control means for executing feedback control based on the vehicle body vibration state and outputting a control signal to the actuator, and depending on the engine speed. And a feedback gain setting means for setting a feedback gain of the control means, the active dynamic vibration absorber for a vehicle. 2. The vehicle body vibration state detecting means detects displacement and speed of vibration as the vehicle body vibration state, and the feedback gain setting means determines whether the vehicle body vibration is in a low frequency mode or a high frequency mode based on the engine speed. When it is determined that the mode determination means is a low frequency mode, a feedback gain that puts a weight on the displacement of the vibration is set, and when it is determined that the mode is a high frequency mode. 2. The active dynamic vibration absorber for a vehicle according to claim 1, wherein a feedback gain that sets a weight on the speed of the vibration is set for.