JPH0585310A - Wiper control device - Google Patents

Abstract

PURPOSE:To drive a wiper blade at most suitable intervals corresponding with driver's sensation by restricting wiping-off operations for large raindrops which are relatively small in deterioration of visibility. CONSTITUTION:Output signals from a raindrop sensor 4 are discriminated by a comparator 41 for a discriminating level V1 and a wind comparator 42 for discriminating levels V2a, V2b, and waveform-shaped into a large signal raindrop pulse S1 and a small signal raindrop pulse S2. A wiper blade is driven when the raindrop pulse S2 more than a threshold value RN is relatively frequently detected within a period of time W2, and the accumulated value M1 of the raindrop pulse S1 reaches a threshold value RP or more. Thus, the wiping-off operation are restricted for large raindrops which do not deteriorate visibility so much, without reducing response sensibility of the wiper at the time of usual rainfall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiper control device which is suitable for use on a vehicle and drives a wiper blade at a wiping interval suitable for a rainfall condition.

[0002]

2. Description of the Related Art In a so-called automatic wiper control apparatus for driving a wiper blade at a wiping interval suitable for rainfall, a typical prior art is to perform level discrimination of an output signal from a raindrop sensor at a predetermined discrimination level and then discriminate the discrimination. The wiper blade is configured to be driven at the time when the time period which is equal to or higher than the level is integrated and the integrated value becomes equal to or higher than a predetermined threshold value.

[0003]

Therefore, in the above-mentioned prior art, when a relatively large raindrop is detected,
One or two drops exceed the threshold value, and the wiping operation is performed. However, when the raindrop diameter becomes larger than a certain amount, raindrops adhering to the windshield flow down and the forward visibility does not deteriorate so much, whereas in the case of extremely small raindrops such as drizzle or raindrops that the preceding vehicle jumped up. However, even if the amount of rainfall is extremely small, the forward visibility is extremely deteriorated. For this reason, in the above-mentioned conventional technique, although the forward visibility is not deteriorated when the raindrop diameter is large,
When the wiping operation is performed and the raindrop diameter is small, on the other hand, there is a problem that the wiping operation is not performed despite the deterioration of the forward visibility.

Further, the raindrop sensor is arranged in an automobile, for example, in a hood or a front grill, which is away from the windshield, which is a region where the rain condition should be detected, and the raindrop detection range is defined by the windshield. The area is extremely narrow as compared with the area, so that the detection results of the raindrop sensor vary. Therefore, especially when the raindrop diameter is large, the wiping interval fluctuates greatly,
It makes the driver feel uncomfortable.

An object of the present invention is to provide a wiper control device capable of driving the wiper blade at an optimum wiping interval that matches the feeling of the operator.

[0006]

According to the present invention, a raindrop sensor for deriving an output signal of a level corresponding to a raindrop diameter and a wiper blade for removing raindrops adhering to a surface to be wiped are provided on the surface to be wiped. Driving means for reciprocating displacement driving, comparing means for discriminating the output signals of the raindrop sensor at a plurality of different discriminating levels, and discriminating results according to the discriminating levels of the comparing means are individually integrated, and at least any one of When one integrated value is equal to or greater than a preset threshold value for each integrated value, the control means for outputting a drive signal indicating that the wiper blade should be driven to the drive means and the output of the comparison means are Given, among the plurality of discrimination levels,
A wiper control device comprising: a prohibition unit that prohibits the output of the drive signal by the control unit when the discrimination result by the comparatively small discrimination level is less than a predetermined value within a predetermined time.

[0007]

According to the present invention, the output signal from the raindrop sensor is level discriminated by the discrimination means at a plurality of discrimination levels different from each other, and the discrimination result is inputted to the control means. The control means individually integrates the discrimination results by the discrimination levels of the comparison means, and at least one of the integrated values is
A drive signal is output to the drive means when the threshold value is preset for each integrated value. In response to the drive signal, the drive unit drives the wiper blade to reciprocate on the surface to be wiped such as the windshield to remove raindrops and the like adhering to the surface to be wiped.

On the other hand, the output of the comparing means is also given to the prohibiting means, and the prohibiting means is predetermined within a predetermined time for the discrimination result by the comparatively small discrimination level among the plurality of discrimination levels. When it is less than the value,
That is, when the number of raindrops is not too large, it is determined that the raindrop integrated value has reached the threshold value only with relatively large raindrops, and the control means stops the output of the drive signal. As a result, when the diameter of the raindrop is large, the wiping operation can be restricted as compared with the normal raindrop, and the wiping operation that matches the operator's feeling can be performed. Further, even if the detection result of the raindrop sensor varies, the wiping interval does not change undesirably, and a stable wiping operation can be performed.

[0009]

1 is a block diagram showing the electrical construction of a wiper control apparatus 1 according to an embodiment of the present invention. The wiper control device 1 is used for a vehicle, and when the auto wiper switch 2 is turned on, the control circuit 3 responds to an output from the raindrop sensor 4 to drive and control a wiper motor 5 which is a driving unit. This is a so-called automatic wiper control device that performs a wiping operation by reciprocally displacing the wiper blade on the windshield.

The raindrop sensor 4 includes, for example, a pair of light emitting / receiving elements, and an optical element for detecting the amount of rainfall based on a change in the light receiving level caused by the raindrops passing through the optical path formed by these light emitting / receiving elements. It is a raindrop sensor.

The output signal of the raindrop sensor 4 is input to the control circuit 3 and given to a comparator 41 and a window comparator 42 which are comparison means. The comparator 41 includes a comparison circuit C1 and voltage dividing resistors R1a and R1b.
It is configured to include and. The output signal from the raindrop sensor 4 is applied to one terminal of the comparator circuit C1 and the voltage V1 obtained by dividing the high level voltage + B by the voltage dividing resistors R1a and R1b is applied to the other terminal. Has been entered.

Similarly, the window comparator 42 has two
Two comparison circuits C2a and C2b and voltage dividing resistors R2a and R2
b and R2c. Comparison circuit C2a
To one terminal and the other terminal of the comparison circuit C2b,
The output signal from the raindrop sensor 4 is input. The high-level voltage + B is divided by the voltage dividing resistors R2a, R2b, and R2c, and the voltage V2a at the connection point between the resistors R2a and R2b is given to the other input of the comparison circuit C2a and the resistor R2b. The voltage V2b at the connection point between the resistor R2c and the resistor R2c is applied to one input of the comparison circuit C2b.

The voltage V1 is set to a relatively high value, for example, 0.4 V, the voltage V2b is lower than the voltage V1, and the voltage near the minimum value level of the output signal from the raindrop sensor 4 is set. , For example, it is set to 0.1V. Furthermore, the voltage V2a is equal to the voltage V2.
It is set to be slightly higher than b, for example, 0.15V.

Therefore, when the output signal from the raindrop sensor 4 is shown in FIG. 2 (1), the output signal from the raindrop sensor 4 is output from the comparator 41 as shown in FIG. 2 (3). The raindrop pulse S1 is derived only during the above period. Further, as shown in FIG. 2B, the output signal from the raindrop sensor 4 from the window comparator 42 is equal to or higher than the voltage V2b and the voltage V2a.
The raindrop pulse S2 is output only during the following period.

The raindrop pulses from the comparator 41 and the window comparator 42 are realized by a microcomputer or the like, and are input to the processing circuit 12 which is a control means and a prohibition means. The output of the auto wiper switch 2 is processed by the waveform shaping circuit 13 after the noise component such as so-called chattering is removed.
Entered in 2.

Therefore, in the normal rainfall condition shown in FIG. 2, the auto wiper switch 2 is turned on and the detection is started from the time t1, and reference signs q1, q2, q3 ,.
.. As shown in FIG. 2, raindrops are detected.
2 corresponds to the raindrop pulse S1 indicated by (3).
As shown in (4), the pulse widths are integrated. When the integrated value M1 of the integrated pulse width becomes equal to or larger than the predetermined threshold value RP, the wiping operation is performed at time t2 as shown in FIG. 2 (5), and the integrated value M1 is reset to zero.

A predetermined time W from the time t1
2, the number of raindrops detected by the time t3 when 2 seconds elapse, for example, is 6, and therefore the processing circuit 12
Determines that the raindrops from the large diameter to the small diameter are uniformly detected, and performs the wiping operation as described above at the time t2 after the time t3.

On the other hand, when the integrated value M1 becomes equal to or greater than the threshold value RP and the number of detected raindrops is a predetermined value RN, for example, less than 5, only relatively large raindrops are detected. Therefore, the wiping operation is prohibited as shown in FIG. FIG. 3 is a timing chart for explaining the operation in the case where the number of raindrops is small and the influence of relatively large raindrops is large.
(1) to (5) are respectively the above-mentioned FIG. 2 (1) to (5).
It corresponds to.

That is, even if the integrating operation is started from the time t11 and the integrated value M1 becomes equal to or more than the threshold value RP at the time t12, the number of raindrops detected from the time t11 to the time t13 when the time W2 has elapsed is still the same. As shown in FIG. 3B, when the number is less than 5,
The original wiping operation indicated by the virtual line in FIG.

A constant voltage circuit 29 is connected from the power supply line L2 to each circuit in the control circuit 3 including the processing circuit 12.
The electric power from the battery 23 is supplied via the. When power is supplied from the constant voltage circuit 29 and the auto wiper switch 2 is turned on, the processing circuit 12 integrates the pulse width of the raindrop pulse from the comparator 41 as described above, and the integrated value M1. When becomes equal to or higher than a predetermined threshold value RP, the wiper motor 5 is driven.

When the wiper motor 5 is driven at a low speed, the processing circuit 12 outputs a drive signal from the output terminal P2 to the line L3. This drive signal is given to the base of the transistor Tr2 via the resistor R3 and the bias resistor R4. The emitter of the transistor Tr2 is grounded, and the collector is connected to the power supply line L2 via the relay coil 27 of the relay 26.

On the other hand, the relay switch 2 of the relay 26
8 has two individual contacts 28a, 28b, one individual contact 28b is connected to the power supply line L2, and the other individual contact 28a is connected to a common contact 30c of the cam switch 30 via a line L4. There is. The common contact 24c of the relay switch 24 of the relay 21 is connected to the common contact 28c of the relay switch 28, and one individual contact 24a of the relay switch 24 is connected to the low speed power input terminal 5a of the wiper motor 5. ..

When the wiper motor 5 is continuously driven at high speed, the processing circuit 12 also outputs drive signals from the output terminals P1 and P2 to the lines L1 and L3. The drive signal on the line L1 is input to the base of the transistor Tr1 via the resistors R1 and R2, and the drive signal on the line L3 is input to the base of the transistor Tr2 via the resistors R3 and R4.

The emitter of the transistor Tr1 is grounded, and the collector is the relay coil 22 of the relay 21.
Is connected to the power supply line L2 via. The other individual contact 24b of the relay switch 24 of the relay 21 is
It is connected to the high speed power input terminal 5b of the wiper motor 5.

A cam switch 30 is provided in association with the wiper motor 5, and the cam switch 30 includes:
When the wiper blade is in the initial position, it is electrically connected to the individual contact 30a, the wiper motor 5 is activated, the wiper blade starts the wiping operation, and when the wiper blade is separated from the initial position, it is electrically connected to the individual contact 30b. When the blade finishes the wiping operation and returns to the initial position again, it conducts to the individual contact 30a.

The individual contact 30a is grounded together with the ground terminal 5c of the wiper motor 5, and the individual contact 30b is
It is connected to the power supply line L2. Also common contact 3
0c is connected to the individual contact 28a of the relay switch 28 via a line L4, and the common contact 3
The voltage of 0c is detected by the processing circuit 12 from the line L5 via the signal processing circuit 31. Processing circuit 12
Determines whether the wiper blade is in the wiping operation from the detected voltage of the common contact 30c.

Therefore, the processing circuit 12 outputs a drive signal from the output terminal P2 to the line L3 when driving the wiper motor 5 at a low speed. As a result, the transistor Tr2 becomes conductive, the relay coil 27 is excited, and the contacts 28b and 28c of the relay switch 28 become conductive.
Therefore, the battery 23 through the power supply line L2
Is supplied from these contacts 28b, 28c to the low speed power supply input terminal 5a of the wiper motor 5 via the contacts 24c, 24a of the relay switch 24.

In this way, the wiper motor 5 is activated and the cam switch 30 is switched from the individual contact 30a to the individual contact 30b, and when the wiper blade is returned to the initial position thereafter, the cam switch 30 is switched from the individual contact 30b to the individual contact 30a again. The processing circuit 12 stops outputting the drive signal. As a result, a brake current flows through the low speed power input terminal 5a of the wiper motor 5 through the contacts 30a, 30c, the contacts 28a, 28c of the relay switch 28, and the contacts 24c, 24a of the relay switch 24, and the wiper motor 5 stops. To do.

Further, when the wiper motor 5 is driven at high speed, the processing circuit 12 outputs drive signals from the output terminals P1 and P2, and thereby the transistors Tr1 and Tr2.
Is conducted, the relay coils 22 and 27 are both excited, the relay switch 24 conducts to the individual contact 24b, and the relay switch 28 conducts to the individual contact 28b. As a result, the electric power from the battery 23 is supplied to the high speed power input terminal 5b of the wiper motor 5 via the relay switches 28 and 24.

The processing circuit 12 detects from the output voltage level of the cam switch 30 whether or not the wiper blade has returned to the initial position, and the output terminals P1 and P2 from the output terminals P1 and P2 until the wiper blade returns to the initial position. Continue to derive drive signals. In this way, the wiper motor 5 can be driven at low speed and high speed.

FIG. 4 is a flow chart for explaining the above-mentioned automatic wiper control operation. At step n1, initialization processing such as zero reset of the integrated value M1 is performed. At step n2, it is judged whether or not the raindrop pulse S1 is detected from the comparator 41. If so, at step n3, the pulse width Ma of the raindrop pulse S1 is added to the integrated value M1 to obtain the integrated value M1. Will be updated.

At step n4, the predetermined time W is set.
It is determined whether or not 2 sec, which is 2, has elapsed, and if so, in step n5, the control prohibition flag F1 is temporarily set.
Is set to 1, and in step n6, the count value M2 of the pulse number of the raindrop pulse S2 from the window comparator 42 is reset to zero, and then the process proceeds to step n7. If not, the process directly proceeds to step n7.

In step n7, it is judged whether or not the raindrop pulse S2 is detected, and if so, in step n8, the counting operation of the count value M2 is performed. In step n9, it is determined whether or not the count value M2 has become equal to or greater than the predetermined threshold value RN of 5, and if so, the control prohibition flag F1 is reset to zero in step n10, and in step n11. After the count value M2 is reset to zero, the process proceeds to step n12, and if not, the process directly proceeds to step n12.

In step n12, it is judged whether or not the integrated value M1 integrated in step n3 becomes equal to or more than the threshold value RP, and if so, is the control prohibition flag F1 set to 1 in step n13. It is determined whether or not it is not so, that is, when the integrated value M1 becomes equal to or more than the threshold value RP in a state where the raindrops from the large diameter to the small diameter are uniformly detected, the process proceeds to step n14. At step n14, the integrated value M1 is reset to zero.

At step n15, drive signals are selectively output from the terminals P1 and P2 of the processing circuit 12 to activate the wiper motor 5. In step n16, it is determined whether the common contact 30c of the cam switch 30 is switched to the individual contact 30b, that is, whether the wiper blade has left the initial position and started the wiping operation, and when the wiping operation is started, step n17. Move on to. In step n17,
The common contact 30c of the cam switch 30 is the individual contact 30.
It is determined whether or not it has been switched to a, that is, whether or not the wiping operation has been completed, and when the wiping operation is completed, step n
Go to 18. In step n18, the output of the drive signal is stopped, the wiper motor 5 is stopped, and then the process returns to step n2. When the integrated value M1 is less than the threshold value RP in step n15, and
When the control prohibition flag F1 is 16 in 16,
The process directly returns to step n2.

As described above, the threshold R
Since the wiping operation is performed only when the number of raindrops of N or more is detected relatively frequently and the integrated value M1 becomes equal to or more than the threshold value RP, the number of raindrops is small and the integrated value M1 is affected by the large raindrops. Is greater than or equal to the threshold value RP, the wiping operation can be prohibited, and the wiping operation for large raindrops with relatively little deterioration of the forward visibility is limited to perform the wiper control operation that matches the driver's feeling. be able to.

Further, with respect to the variation of the detection result due to the narrow detection range of the raindrop sensor 4 and the mounting position,
A stable wiper control operation can be performed.

[0038]

As described above, according to the present invention, the output signals of the raindrop sensor are level discriminated at a plurality of discrimination levels, the discrimination results are integrated, and the wiping operation is controlled based on the integrated value. The wiping operation is prohibited when the discrimination result based on a relatively small discrimination level is less than a predetermined value within a predetermined time, that is, when the number of raindrops is relatively small, so the wiping operation is performed at an optimum wiping interval that matches the operator's feeling. Can be done. Further, even if the detection result varies due to the narrow detection range of the raindrop sensor, it is possible to perform a stable wiping operation without undesirably changing the wiping interval.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a wiper control device 1 according to an embodiment of the present invention.

FIG. 2 is a timing chart for explaining an operation during normal rainfall.

FIG. 3 is a timing chart for explaining an operation in a state where the number of raindrops is small.

FIG. 4 is a flowchart for explaining an automatic wiper control operation.

[Explanation of symbols]

 1 Wiper control device 2 Auto wiper switch 3 Control circuit 4 Raindrop sensor 5 Wiper motor 12 Processing circuit 30 Cam switch 41 Comparator 42 Wind comparator

Claims (1)

[Claims] 1. A raindrop sensor for deriving an output signal of a level corresponding to a raindrop diameter, and a drive means for driving a wiper blade for removing raindrops adhering to the surface to be wiped back and forth on the surface to be wiped. Comparing means for discriminating the output signals of the raindrop sensor at a plurality of different discriminating levels, and discriminating results by the discriminating levels of the comparing means are individually accumulated, and at least one of the accumulated values is the accumulated value. The control means for outputting a drive signal indicating that the wiper blade should be driven to the drive means when the threshold value is preset or more for each, and the output of the comparison means is given to the plurality of discrimination levels. Of the above, when the discrimination result by the comparatively small discrimination level is less than the predetermined value within the predetermined time, prohibition of outputting the drive signal by the control means is prohibited. Wiper control apparatus characterized by comprising a stage.