JPH10194090A - Prevention device for chattering vibration of wiper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely prevent the chattering vibration of a wiper, and surely restrain the occurrence of chattering vibration without hurting an user's feeling. SOLUTION: In the prevention device 10 for the chattering vibration of a wiper, when the constituent of chattering vibration taken out of a vibration sensor 5 exceeds a reference value, a control signal reverse in phase with the constituent of chattering vibration is generated so as to be synchronized with the constituent of chattering vibration, and a control signal synchronized as mentioned above, is combined with a driving signal from a wiper control unit 20 so as to be outputted to a wiper motor 3. By this constitution, the wiper motor 3 is actively controlled in such a way that force reverse in phase with chattering vibration is applied to the wiper motor, so that chattering vibration is thereby canceled. In the device as mentioned above, any user's feeling is prevented from being hurt by a step against user's intention such as a proposal and the like where the wiper motor 3 is increased in torque so as to allow a wiper to be driven at the high speed, and chattering vibration can thereby be surely suppressed under any condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing chatter vibration of a windshield wiper, which suppresses the chatter vibration when the wiper moves while vibrating little by little.

[0002]

2. Description of the Related Art Conventionally, in a wiper for wiping a window glass of a vehicle such as an automobile, chattering vibration that moves while vibrating little by little may occur.
This is likely to occur when the wind glass surface is semi-dry, when a water repellent is used, when the wiper blade is deteriorated, and the like.

[0003] As a countermeasure against chatter vibration, measures such as increasing rigidity of members constituting the vibration system and providing a damping mechanism are taken, but they are not always sufficient. For this reason,
Japanese Patent Application Laid-Open No. 61-64562 discloses a technique in which when the chattering state of the wiper is detected, the torque of the wiper motor is increased to increase the wiping speed of the wiper, thereby eliminating the chattering state.

[0004]

However, in the above-mentioned prior art, when chatter vibration of the wiper occurs, the wiper suddenly moves at a high speed from the wiper wiping speed set by the user, which is contrary to the intention of the user. The operation performed may not only cause discomfort, but may be determined to be a failure.

The present invention has been made in view of the above circumstances, and performs active control for chatter vibration of a wiper.
It is an object of the present invention to provide an anti-vibration device for a wiper that can surely suppress chatter vibration without giving a user discomfort.

[0006]

According to the first aspect of the present invention,
Means for detecting chatter vibration generated in the wiper for wiping the window glass; means for generating a signal having a phase opposite to the chatter vibration when the chatter vibration of the wiper is detected; and detecting chatter vibration of the wiper. When the drive signal is output to the actuator for driving the wiper,
Means for combining the drive signal when the chatter vibration of the wiper is not detected with the signal of the opposite phase to form a signal.

According to a second aspect of the present invention, in the first aspect of the invention, the actuator is a motor, and chatter vibration of the wiper is detected based on a change in a drive current of the motor.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the signal having the opposite phase is generated based on preset signal waveform data.

That is, according to the present invention, when chatter vibration of the wiper for wiping the window glass is detected, a signal having a phase opposite to the chatter vibration is generated, and a drive signal output to an actuator for driving the wiper is generated. The phase signal and the drive signal when no chattering vibration is detected are output as a combined signal.

At this time, when the actuator for driving the wiper is a motor, chatter vibration can be detected based on a change in the drive current of the motor, and the chatter vibration having the opposite phase to the chatter vibration can be detected based on preset signal waveform data. A signal can be generated.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show a first embodiment of the present invention.
FIG. 1 is a block diagram of the chatter vibration preventing device, FIG. 2 is an overall configuration diagram of the wiper device, FIG. 3 is a general vibration waveform diagram of the wiper, FIG. 4 is a waveform diagram of chatter vibration components, and FIG. FIG. 6 is a configuration diagram in the case where chatter vibration is detected by a wiper motor current.

In FIG. 2, reference numeral 1 denotes a wiper mounted on a vehicle such as an automobile. In the figure, a tandem type wiper for wiping a window glass (front window glass) 2 is shown. The wiper 1 has a wiper arm 1b supporting a wiper blade 1a for wiping raindrops or the like adhering to the window glass 2, and is connected to a wiper motor 3 via a link mechanism and a speed reduction mechanism (not shown).

The wiper motor 3 includes a chatter vibration preventing device 1 for preventing chatter vibration during the wiping operation of the wiper 1.
0 to the wiper control unit 20;
A signal from the wiper switch 4 or a washer switch (not shown) is input to the wiper control unit, and a wiping speed and an intermittent operation cycle of the wiper 1 are set based on the signal from the wiper switch 4 to output a drive signal to the wiper motor 3. At the same time, a drive signal is output to a not-shown washer motor for ejecting the window washer liquid based on a signal from a not-shown washer switch.

Further, the chatter vibration preventing device 10 includes:
A signal of a vibration sensor 5 composed of a strain gauge or an acceleration sensor attached to the wiper arm 1b of the wiper 1 and a drive signal of the wiper motor 3 from the wiper control unit 20 are input. When the occurrence of vibration is detected, the drive signal from the wiper control unit 20 and the control signal having the opposite phase to the chatter vibration are combined, and the combined signal is used as the wiper motor 3.
To control the driving force of the wiper motor 3 to suppress chatter vibration. Note that, in FIG.
Is mounted on the driver's seat-side wiper, which has a large wiping range (long wiper length) and is prone to chatter vibration.

That is, the chatter vibration generated in the wiper 1 is a type of self-excited vibration caused by uneven friction in the contact surface between the window glass 2 and the wiper blade 1a. It happens in the first place. Accordingly, the chatter vibration can be canceled by detecting the chatter vibration of the wiper 1 and actively controlling the wiper motor 3 so that a force having a phase opposite to the chatter vibration is applied.

For this reason, as shown in FIG. 1, the chattering vibration preventing device 10 includes a filter 11 for extracting a chattering vibration component from a signal of the vibration sensor 5, a chattering vibration generating device including a sample-and-hold circuit, a comparing circuit, and the like. A control signal generation unit 1 including a determination unit 12, a function generator including a memory 14, an address counter, and a clock generation circuit;
3, a synchronization processing unit 15 including a delay circuit and the like, and a drive signal synthesizing unit 16 including an adder and the like. When the chatter vibration component extracted from the signal of the vibration sensor 5 exceeds a reference value, the chatter vibration A control signal having a phase opposite to that of the component is generated and synchronized with the chatter vibration component. The synchronized control signal and the drive signal from the wiper control unit 20 are combined and output to the wiper motor 3.

The operation of the chatter vibration preventing device 10 having the above configuration will be described below.

First, when the wiper switch 4 is turned on,
A drive signal of the wiper motor 3 (a binary signal of a reference voltage level corresponding to ON and OFF of the wiper switch 4 and a ground level) corresponding to the wiper switch 4 is output from the wiper control unit 20 and output to the wiper motor 3 via the chatter vibration preventing device 10. You. The signal output to the wiper motor 3 is such that the chatter vibration preventing device 10
Since the control signal for suppressing the chatter vibration is not generated inside, the drive signal from the wiper control unit 20 is output to the wiper motor 3 without being changed.

Then, the wiper 1 is driven by the wiper motor 3.
Is driven to start the wiping operation of the window glass 2 by the wiper blade 1a supported by the wiper arm 1b, the vibration of the entire wiper is detected by the vibration sensor 5 and input to the chatter vibration preventing device 10. In the chatter vibration prevention device 10, the filter 1
A vibration component within a predetermined frequency range is extracted via 1 and the chatter vibration occurrence determination unit 12 compares the vibration component with a reference value to determine whether chatter vibration has occurred. That is, when a small vibration component is on the vibration waveform of the entire wiper as shown in FIG. 3, only a small vibration component is extracted from the whole vibration waveform by the filter 11 as shown in FIG. When the level exceeds the reference value, it is determined that chatter vibration has occurred.

In this case, as described above, chatter vibration is a kind of self-excited vibration and can be regarded as a simple vibration having the same amplitude at all times, and its amplitude (single amplitude) a is 1 mm.
And the frequency f is about 20 Hz. Therefore, for example, when chatter vibration is detected by displacement (force) using a strain gauge as the vibration sensor 5, a = 1 mm is adopted as the reference value for determining occurrence of chatter vibration. When chatter vibration is detected by acceleration using a sensor, a speed amplitude of 2πfa to 12
5.6 mm / s is adopted as a reference value.

When the chatter vibration occurrence judging section 12 judges that chatter vibration has occurred, a control signal generation command for suppressing the chatter vibration is output to the control signal generating section 13, and
The control signal generator 13 reads out the signal waveform data stored in the memory 14 in advance and generates a control signal having a phase opposite to that of the chatter vibration component. The waveform of the control signal does not necessarily have to be exactly the same waveform in the opposite phase to the waveform of the chatter vibration component, and may be any disturbance signal that can destroy the self-excited vibration system.

Next, the control signal is delayed by the synchronization processing section 15, synchronized with the chatter vibration signal, and sent to the drive signal synthesis section 16. In the drive signal synthesis unit 16,
A control signal synchronized with chatter vibration is transmitted to the wiper control unit 2.
This signal is superimposed on the drive signal from 0, and this signal is output to the wiper motor 3 as a final drive signal.

The control signal is output as a signal of about two cycles as shown in FIG. That is, the chatter vibration is a simple vibration. Basically, it is possible to sufficiently suppress the chatter vibration by adding a control signal having an opposite phase for one cycle. Add a minute control signal.

Thus, the user does not feel uncomfortable by taking measures against the user's intention, such as increasing the torque of the wiper motor 3 to suppress the chatter vibration and performing the wiping operation of the wiper 1 at high speed. Chatter vibration can be reliably suppressed under the conditions.

By utilizing the fact that when the chatter vibration occurs, the drive current of the wiper motor 3 changes, the current waveform signal of the wiper motor 3 is filtered instead of the signal from the vibration sensor 5 as shown in FIG. 11 may be input. In this case, since the control signal is fed back, divergence of the system is concerned. However, a certain time is required from the input of the current waveform signal to the generation of the control signal, and the system does not become a divergent system.

FIGS. 7 and 8 relate to a second embodiment of the present invention. FIG. 7 is a block diagram of a chatter vibration preventing device.
9 is a flowchart of a chatter vibration prevention routine.

In this embodiment, each function of the chatter vibration preventing device 10 in the above-described first embodiment, that is, the chatter vibration occurrence judging section 12, control signal generating section 13, synchronization processing section 15,
The function of the drive signal synthesizing unit 16 is
Is realized by software processing.

As shown in FIG. 7, the computer unit 30 includes a CPU 31, a ROM 32, a RAM 33,
A / D converter 34, I / O interface 35, D
A / A converter 36 and the like are mainly connected to a microcomputer connected to each other via a bus line, and other peripheral circuits (not shown) are provided.
The drive signal of the wiper motor 3 from 0 is input through the I / O interface 35, and the signal that has passed through the filter 11 from the vibration sensor 5 is input through the A / D converter 34, and the D / A A signal from converter 36 is output to wiper motor 3 via drive circuit 37.

In this embodiment, the wiper control unit 20 and the computer unit 30 for preventing chatter vibration are separated for convenience of explanation, but the function of the wiper control unit 20 is included in the computer unit 30. The wiper control function and chatter vibration prevention function may be realized by one device. Further, as described above, the current waveform of the wiper motor 3 may be input to the filter 11 instead of the vibration sensor 5.

In this embodiment, the computer unit 3
When a drive signal is input from the wiper control unit 20 to 0, the chatter vibration prevention routine shown in FIG.

In this routine, first, at step S101
And is input from the vibration sensor 5 via the filter 11,
The A / D-converted vibration component data is read by the A / D converter 34, and in step S102, the amplitude of the vibration component is compared with a reference value to check whether chatter vibration has occurred.

If the amplitude of the vibration component is equal to or smaller than the reference value, it is determined that chatter vibration has not occurred, and the process proceeds from step S102 to step S103 to set the drive voltage of the wiper motor 3 as the reference voltage, and then to step S107. A jump is made and the signal of this reference voltage is output from the D / A converter 36 to the wiper motor 3 via the drive circuit 37, and the routine exits.

In this case, the drive signal finally output to the wiper motor 3 is the same as the drive signal output from the wiper control unit 20. Therefore, an analog switch for switching between the output of the D / A converter 36 and the output from the wiper control unit 20 and supplying the output to the drive circuit 37 is provided in the computer unit 30, and it was determined that chatter vibration did not occur. Sometimes, a drive signal from the wiper control unit 20 may be output via an analog switch.
When the function of 0 is processed by the computer unit 30,
Without using an analog switch as described above, D /
Speed control and the like can be performed by changing the drive voltage of the wiper motor 3 using the A converter 36.

On the other hand, if the amplitude of the vibration component exceeds the reference value in step S102, it is determined that chatter vibration has occurred, and the flow advances from step S102 to step S104 to control the control signal from the predetermined address in the ROM 32. The waveform data is read, and the waveform data is superimposed on the reference voltage data to obtain a drive voltage for the wiper motor 3, and a step S1
At 07, the D / A converter 36 performs D / A conversion of the superimposed drive voltage signal, outputs the signal to the wiper motor 3 via the drive circuit 37, and exits the routine.

Also in this embodiment, the chatter vibration can be reliably suppressed without giving the user discomfort, as in the first embodiment.

[0036]

As described above, according to the present invention, when chatter vibration of the wiper for wiping the window glass is detected, a signal having a phase opposite to the chatter vibration is generated and output to the actuator for driving the wiper. The drive signal to be output is output as a signal obtained by synthesizing the signal having the opposite phase and the drive signal when chatter vibration is not detected. An excellent effect is obtained such that chatter vibration can be reliably suppressed under any conditions without giving the user any discomfort due to the countermeasures.

[Brief description of the drawings]

FIG. 1 is a block diagram of a chatter vibration preventing device according to a first embodiment of the present invention.

FIG. 2 is an overall configuration diagram of the wiper device according to the first embodiment;

FIG. 3 is an overall vibration waveform diagram of the wiper according to the first embodiment;

FIG. 4 is a waveform diagram showing chatter vibration components according to the first embodiment;

FIG. 5 is a waveform diagram of a control signal according to the first embodiment;

FIG. 6 is a configuration diagram for detecting chatter vibration by a wiper motor current;

FIG. 7 is a block diagram of a chatter vibration preventing device according to a second embodiment of the present invention.

FIG. 8 is a flowchart of the chatter vibration prevention routine.

[Explanation of Signs] 1 ... wiper 2 ... window glass 3 ... wiper motor 5 ... vibration sensor 10 ... chatter vibration prevention device

Claims (3)

[Claims] 1. A means for detecting chatter vibration generated in a wiper for wiping a window glass; a means for generating a signal having a phase opposite to the chatter vibration when the chatter vibration of the wiper is detected; Means for, when chatter vibration is detected, a drive signal to be output to an actuator for driving the wiper, a signal obtained by combining a drive signal when the chatter vibration of the wiper is not detected and the signal having the opposite phase. A chatter vibration preventing device for a wiper. 2. The apparatus according to claim 1, wherein the actuator is a motor, and the chatter vibration of the wiper is detected based on a change in a driving current of the motor. 3. The apparatus according to claim 1, wherein the anti-phase signal is generated based on preset signal waveform data.