JP2009092503A - Vehicle wiper controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ensure a long time including a wiper operation time when rain drops are detected. <P>SOLUTION: A wiper controller has a light receiving element 12 for receiving light reflected by a plurality of sensing faces D, and controls a wiper from an estimated rainfall condition. A plurality of the sensing faces D are set to positions in which a passage of the wiper is simultaneously detected. The wiper controller comprises: a change detecting section 40 for detecting a change in each sensing face D from an output of the light receiving element 12; a cause determining section 50 for determining a cause of the change from the number of the sensing faces D on which the change is detected; and a rainfall condition estimating section 60 for extracting a fluctuation in the output of the light receiving element due to the wiper from a determination result, and estimating a rainfall condition from the output of the light receiving element 12 expect for the extracted fluctuation in the output due to the wiper. A portion due to the wiper can be identified in the output of the light receiving element 12. The rain drops can be detected even if the wiper is operated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle wiper control device that controls a wiper based on a detection result of a raindrop sensor.

Various raindrop sensors used in vehicles have been proposed. For example, there is a raindrop sensor using an optical system (Patent Document 1).
International Publication No. 2004/101333 Pamphlet

FIG. 9 is a diagram illustrating the configuration of a conventional raindrop sensor and the principle of raindrop detection.
In a conventional raindrop sensor using an optical system as disclosed in Patent Document 1, light emitted from a light emitting element is reflected by a detection surface, and the reflected light is received by a light receiving element to detect raindrops (FIG. 9 (a)). Specifically, when water or the like adheres to the detection surface, the light reflection condition on the detection surface changes and the amount of light received by the light receiving element changes (see FIG. 9B). A change in the amount of light received by the element is detected and raindrops attached to the detection surface are detected.

When wiping with a wiper or controlling the wiping speed is performed based on the detection result of the raindrop sensor, the detection surface of the raindrop sensor is provided so as to be located within the wiping area of the wiper.
Since the wiper moves while collecting rain on the windshield glass, when the wiper passes over the raindrop sensor, the reflection state of light on the detection surface changes due to the collected rain, and the amount of light received by the light receiving element changes. To do.
Therefore, it is difficult to determine whether the change in the amount of received light captured by the light receiving element is due to raindrops adhering to the glass surface or due to the passage of the wiper.

FIG. 10 is a diagram for explaining the relationship between the wiper driving time and the raindrop detection period.
In order to reliably detect only raindrops, it is necessary to set the raindrop detection period to a period when the wiper is stopped or a short time before and after the wiper passes the detection surface of the raindrop sensor. In this case, the raindrop detection period is determined based on a wiper drive signal output from a wiper motor that drives the wiper.
For example, as shown in FIG. 10A, while the wiper drive signal (A / S signal) is ON (period A), the wiper is operating, so the wiper is not operating. The period (period B) is a raindrop detection period, and raindrop detection is performed based on the output value (PD value) of the light receiving element in the detection period.

Here, when the wiper is driven continuously, the general drive period A and stop period B are 0.9 s to 1.2 S and 0.12 s, respectively, and the wiper is driven intermittently. Is the time obtained by adding intermittent time to 1.2S and 0.12s, respectively.
Therefore, when the intermittent time is long, as shown in FIG. 10 (b), the wiper stop period B is long, and sufficient time for detecting raindrops is secured, so that detection of raindrops by the raindrop sensor is stable. Can be done.
However, when the intermittent time is short or when the wiper is continuously driven at high speed (HI) or low speed (Lo), the wiper stop period B is very short, and the time for detecting raindrops is sufficient. Since it cannot be ensured, the raindrop detection by the raindrop sensor cannot be performed stably.

For this reason, if the detection result is directly reflected in the operation control of the wiper, the wiper may not be appropriately controlled. Therefore, it is necessary to monitor the detection result by the raindrop sensor for a predetermined time to determine the validity of the detection result, and it takes time to feed back the detection result to the wiper control.
In this case, even when the wiper is operating at high speed under heavy rain conditions, even if the rain condition suddenly changes to a weak rain condition, the wiper wiping speed is immediately switched from high speed to low speed. As a result, the driver may feel uncomfortable with the operation of the wiper.

  An object of the present invention is to provide a wiper control device capable of identifying a portion caused by a wiper in a detection result by a raindrop sensor and detecting a raindrop even when the wiper is operating.

  The present invention is a rain state in which light is emitted from a light emitting element toward a plurality of detection surfaces set in a wiper wiping region of a windshield glass of a vehicle, and light reflected by the detection surface is received by a light receiving element and estimated. The wiper control device that controls the wiper based on the detection surface, wherein the plurality of detection surfaces are set at positions where the passage of the wiper can be detected simultaneously, and changes that detect changes in each detection surface based on the output of the light receiving element Based on the number of detection units, the number of detection surfaces where the change is detected, a cause determination unit that determines the cause of the change, and the variation caused by the wiper of the output of the light receiving element based on the cause of the change is extracted and extracted A rain state estimating unit that estimates the rain state from the output of the light receiving element excluding fluctuations is provided.

According to the present invention, the cause of the change in the detection surface is determined based on the number of detection surfaces where the change is detected, and which part of the output of the light receiving element is wiper based on the determined cause of the change. Whether the fluctuation is caused by
Therefore, a portion caused by the wiper in the output of the light receiving element can be distinguished from a portion based on a cause other than the wiper, for example, adhesion of raindrops, so that the raindrop is detected even when the wiper is operating. In addition, since it is possible to take a long time for raindrop detection, including during the wiper operation, it is possible to stably detect raindrops.

Examples of the present invention will be described below.
FIG. 1 is a block diagram illustrating a schematic configuration of a wiper control device according to an embodiment.
2A and 2B are explanatory diagrams for explaining the configuration of the sensor unit of the wiper control device, in which FIG. 2A is a view of the windshield glass to which the sensor unit is attached as viewed from the outside of the vehicle, and FIG. BB sectional drawing, (c) is the AA sectional view in (a).

  The wiper control device 1 according to the embodiment includes a sensor unit 10 that detects raindrops, an amplification unit 20, a received light amount detection unit 30, a change detection unit 40, a cause determination unit 50, a rainfall state estimation unit 60, And a wiper control unit 70.

The sensor unit 10 is installed in a wiping region of a wiper that wipes the surface of the windshield glass G, which is a surface on the vehicle compartment side of the windshield glass G of the vehicle.
The sensor unit 10 includes four light emitting elements 11a to 11d made of LEDs (hereinafter referred to as “light emitting element 11” unless otherwise distinguished) and two light receiving elements 12a and 12b (hereinafter referred to as both). Unless otherwise distinguished, it is expressed as “light receiving element 12”).
The light emitting element 11 and the light receiving element 12 are formed with four raindrop detection surfaces Da to Dd (hereinafter referred to as “detection surface D” unless otherwise distinguished) on the surface of the windshield glass G. As described above, it is arranged on the control board 13.
Specifically, with reference to the line AA connecting the light receiving elements 12a and 12b, the light emitting elements 11a and 11b and the detection surfaces Da and Db are on one side, and the light emitting elements 11c and 11d and the detection surface are on the other side. Dc and Dd are positioned, and the detection surfaces Da and Db and the detection surfaces Dc and Dd are arranged so as to be symmetrical with respect to the line segment AA.

The light emitted from the light emitting elements 11a and 11c is reflected by the detection surfaces Da and Dc and then received by the light receiving element 12a, and the light emitted from the light emitting elements 11b and 11d is detected by the detection surfaces Db and Dd, respectively. After being reflected, the light is received by the light receiving element 12b.
Here, the area (120 mm ² ) of each detection surface D is about 1 / 10,000, which is very narrow, for example, compared with the area (1300 × 800 mm) of the windshield glass G of a 5-number car. It is a range. The detection surfaces Da to Dd are set at positions close to each other so that the passage of the wiper can be detected simultaneously.
In the case of the sensor unit 10 shown in FIG. 2, the separation distance between the detection surfaces Da-Dc and the separation distance between the detection surfaces Db-Dd are each set to about 20 mm, and the separation distance between the detection surfaces Da-Db The separation distance between the detection surfaces Dc and Dd is set to about 14 mm.
Here, the term “simultaneous” includes not only exact coincidence but also “almost simultaneous” having a predetermined time shift. And “substantially simultaneously” means a time shorter than the time interval when the raindrop hits the detection surface.

As shown in FIG. 2C, each light emitting element 11 is installed on the control substrate 13 at a predetermined angle so that the irradiation light is incident on the surface of the windshield glass G at a predetermined angle θ. In order to receive the light reflected by the windshield glass G, each light receiving element 12 is installed on the control board 13 at a predetermined angle so as to be aligned with the optical path of the reflected light.
A lens 14 is interposed between the light emitting element 11 and the light receiving element 12 and the windshield glass G. The lens 14 guides the light emitted from the light emitting element 11 to the detection surface D of the windshield glass G. A detection surface D having a predetermined size is formed on the surface of the windshield glass G, and reflected light reflected by the detection surface D is guided to the light receiving element 12.

A pulse signal is input to each of the light emitting elements 11a to 11d from a light emission control unit (not shown), and each of the light emitting elements 11a to 11d has a corresponding detection surface Da to each predetermined period (sampling period) defined by the pulse signal. Light is sequentially irradiated toward Dd. The light reflected by each of the detection surfaces Da to Dd is collected by the lens 14 and received by the corresponding light receiving elements 12a and 12b, and each of the light receiving elements 12a and 12b receives a light reception signal at a level corresponding to the amount of light received. (Electrical signal) is generated.
As shown in FIG. 2B, when a water droplet S or the like is attached to the detection surface D, the light emitted from the light emitting element 11 is partially diffused by the water droplet S, and thus the amount of light received by the light receiving element 12. Decreases according to the water droplet S adhering to the detection surface D. Accordingly, the light receiving element 12 gives different levels of output depending on the water droplets S adhering to the detection surface D. Therefore, the change in the output value of the light receiving element 12 causes a change in the state of the detection surface D, for example, a change due to raindrop adhesion Can be detected.

  Here, as the sampling period is shorter, the number of times the light is irradiated onto the detection surface increases, so that the detection accuracy of the change in the detection surface is improved, but the cost increases accordingly. Since the time for the wiper to pass through the detection surface D is approximately 2 to 3 ms, it is preferable to set the sampling period to a time shorter than about 1 ms so that the change in the detection surface due to the passage of the wiper can be detected. . Incidentally, in this embodiment, the sampling period is set to 500 μs.

  The output of the light receiving element 12 of the sensor unit 10 is amplified by the amplification circuit of the amplification unit 20, then digitally converted by the received light amount detection unit 30, and input to the change detection unit 40.

The change detection unit 40 detects a change in the state of each detection surface D based on the output of the light receiving element 12 after digital conversion input from the received light amount detection unit 30, and the number of detection surfaces D from which the change is detected. And the time at which a change is detected.
The number of detection surfaces D where the change is detected and the time when the change is detected are determined based on the output of the light receiving element 12 while the wiper performs the wiping operation once.
Here, the operation of the wiper reciprocating once within the wiping area of the windshield glass is referred to as a wiper operation of one wiper. The number of detected detection surfaces D and the time during which a change is detected are specified.
Whether or not a single wiping operation has been completed is determined based on whether the A / S signal is on or off. Specifically, when the A / S signal is on, the wiper is in the operating position, and when the A / S signal is off, the wiper is in the stop position, so the A / S signal is turned on from off (before wiping). It is detected that a single wiping operation has been completed at a stage where the state has changed to OFF (wiping end) again after (wiping operation in progress).

  FIG. 3 is a diagram for explaining determination of the presence or absence of changes in the detection surfaces Da to Dd. FIG. 3A is an explanatory diagram for explaining block division of output values of the light receiving element 12 input every sampling cycle. (B) is a table explaining the determination result of the presence / absence of a change performed by the change detection unit 40 for each detection surface D.

Since a total of four detection surfaces Da to Dd are set on the surface of the windshield glass G, the change detection unit 40 outputs (output value) after digital conversion of the light receiving element 12 for each of the detection surfaces Da to Dd. Are input at every sampling period.
The change detection unit 40 divides the output of the light receiving element 12 input every sampling period while the wiper performs one wiping operation into blocks divided into a predetermined number of outputs that are consecutive in the input order. Next, it is determined whether or not each of the detection surfaces Da to Dd has changed.

Here, a case where the predetermined number at the time of dividing into blocks is 32 and the output of the light receiving element 12 is that of the detection surface Da will be described as an example.
As shown to (a) of FIG. 3, the change detection part 40 makes the 1st-32nd output continuous in the input order input within predetermined time (16 ms) the 1st block. Then, the output is sequentially divided into blocks for each sampling period such that the new 32 outputs input within the next predetermined time (16 ms) are used as the second block.
In consideration of the difference between the time at which the A / S signal switches and the sampling period, the change detection unit 40 firstly changes after the A / S signal changes from off to on (the wiper starts the wiping operation). From the input of the light receiving element 12 to the output of the light receiving element 12 that is input first after the A / S signal changes from ON to OFF (the wiper completes one wiping operation), the wiper It is processed as an output of the light receiving element 12 input during one wiping operation.

And the change detection part 40 determines the presence or absence of the change of each detection surface Da-Dd for every block.
The determination of the presence / absence of the change of the detection surface D performed by the change detection unit 40 will be described by taking the determination of the presence / absence of the change of the detection surface Da in the first block as an example.
The change detection unit 40 obtains a difference between each output value for the detection surface Da included in the first block and an output value input immediately before (one time before) the input of the output value. For example, in the case of the fifth output value, the difference from the fourth output value is obtained. Note that the difference between the first output value and the 32nd output value of the previous block is obtained.
The change detection unit 40 determines that the detection surface Da has changed when the absolute value of the obtained difference is larger than a predetermined threshold value. At this time, if the input output value is increased (increased) from the previous output value, it is determined as an increase change, and if it is decreasing (decrease), it is determined as a decrease change. Incidentally, when the obtained difference is smaller than a predetermined threshold value, it is determined that there is no change.
Thereby, the presence or absence of a change is determined for all of the 1st to 32nd output values.

The change detection unit 40 assumes that there is a change (upward change) in the detection surface Da of the first block when at least one determination of the upward change is included in the determination results for the first to 32nd output values. .
Similarly, when at least one determination of the downward change is included, it is assumed that there is a change (downward change) in the detection surface Da of the first block.
By the way, when both the determination of the upward change and the determination of the downward change are included, it is assumed that there is an upward change and a downward change on the detection surface Da of the first block. When not included, it is assumed that there is no change in the detection surface Da of the first block.

The determination of the presence / absence of this change is performed for the other detection surfaces Db to Dd included in the first block, and then also for the detection surfaces Da to Dd included in the second and subsequent blocks.
Thereby, for example, information indicating the determination result of the content as shown in the determination result table of FIG. 3B is generated. In the case of this table, the detection surface Da of the first block, the detection surfaces Db and Dc of the second block, the detection surface Dc of the third block, and the detection surface Db of the fourth block had an upward change and a downward change, respectively. It is shown.

  Here, the detection surfaces Da to Dd are arranged close to each other so that changes due to the passage of the wiper can be detected simultaneously. However, due to the sampling cycle, the wiper wiping speed, and the positional relationship between the detection surfaces Da to Dd, changes in the detection surfaces simultaneously caused by the passage of the wiper are detected with a slight temporal shift, and at the same sampling cycle. It may not be detected. In this case, if it is configured to determine whether or not there is a change in the detection surface for each output of the light receiving element 12 input every sampling cycle, the change in each detection surface that occurs at the same time is detected by the output of the different sampling cycles, It may be determined that the detection surface has not changed at the same time.

Therefore, in the present embodiment, the output of the light receiving element 12 input every sampling cycle is divided into blocks divided into a predetermined number of outputs that are consecutive in the input order, and the change of each detection surface Da to Dd is changed for each block. As a configuration for determining the presence or absence, such a situation is prevented from occurring.
Thus, for example, the second output value of the first block indicates that there is a change in the detection surface Da even though there is a change in the detection surface Da and the detection surface Db at the same time, and there is a change in the detection surface Db. Even if the fact is specified in the third output value of the first block, since these are included in the same block, it is determined that the detection surface Da and the detection surface Db have changed simultaneously in the first block. Will be.

When the determination of the presence / absence of a change in the detection surface D included in all the blocks is completed, the change detection unit 40 specifies the number of detection surfaces D in which a change is detected for each block. Then, it is confirmed how many blocks the change in the detection surface D is detected, and the number of confirmed blocks is set as the time during which the change is detected.
Subsequently, the change detection unit 40 generates change information indicating the number of detected detection surfaces and the time during which the change is detected, and outputs the change information to the cause determination unit 50.
For example, in the case of the determination result shown in FIG. 3B, in the first block, the number of detection surfaces D in which a change is detected is “1”, and the time in which the change is detected is “1 block”. In 2 blocks, the number of detection surfaces D on which a change is detected is “2”, the detection time of the change of the detection surface Db is “1 block”, and the detection time of the change of the detection surface Dc is “2 blocks”. Change information indicating that it is present is generated.
Here, when the wiper is operating continuously, change information is generated for each wipe operation of the wiper and is output to the cause determination unit 50.

Depending on how the blocks are divided, the change due to the passage of the wiper may be detected over two blocks with a shift of one block. In this case, it is possible that the cause determination unit 50 determines that no change has been detected on the four detection surfaces Da to Dd at the same time, even though changes have occurred simultaneously on the four detection surfaces Da to Dd.
Therefore, when the change information is generated, the change detection unit 40 checks whether there is a change in each detection surface in two consecutive front and rear blocks (for example, the first block and the second block), and When a change is confirmed only on one of the detection surfaces, it is preferable to prevent the occurrence of such a situation by determining that the change is confirmed also on the same detection surface of the other block.

The cause determination unit 50 refers to the cause map MP stored in a storage unit (not shown) based on the number of detection surfaces in which a change is detected, the time in which the change is detected (detection time), and the wiper on / off state. Then, it is determined whether the detected change in the detection surface is due to the passage of the wiper, due to the splash, or due to the attachment of raindrops.
Here, the number of detection surfaces in which a change is detected and the detection time thereof are specified based on change information input from the change detection unit 40. The on / off state of the wiper is specified based on an A / S signal input from a not-shown wiper motor.

FIG. 4 is an explanatory diagram illustrating a cause map stored in a storage unit (not shown).
In the cause map MP, the number and change of the detection surfaces where the change is detected are detected separately when the wiper is operating (A / S on) and when it is stopped (A / S off). The relationship between the detection time and the cause of the change in the detection surface is defined.

The relationship between the number and detection time of the detection surfaces where the change is detected and the cause of the change in the detection surface will be described.
5A and 5B are diagrams for explaining the output value of the light receiving element after digital conversion, in which FIG. 5A is a diagram showing a waveform showing a change in the output value over time, and FIG. 5B is a solid line in FIG. It is the elements on larger scale of the area | region enclosed by. In this figure, the digitally converted output values of the light receiving element 12 for each of the detection surfaces Da to Dd are superimposed and displayed, the vertical axis is the voltage value (mV), and the horizontal axis is the time (seconds). Is shown.

When a change occurs in the state of the detection surface, such as when a raindrop adheres to the detection surface or a wiper passes over the detection surface, the amount of light received by the light receiving element 12 changes, and the output value of the light receiving element 12 Fluctuates.
The detection surfaces Da to Dd are set at positions where changes due to the passage of the wiper can be detected simultaneously. That is, the wipers are passed close to each other so as to pass over the detection surfaces Da to Dd simultaneously. Here, under normal rain conditions, it is almost impossible for the output values of the detection surfaces Da to Dd output by the light receiving element 12 to fluctuate four times simultaneously or to fluctuate for a long time.

However, when the wiper passes or when, for example, a large amount of water splashed by an oncoming vehicle splashes on the windshield glass G, four output values for each of the detection surfaces Da to Dd change simultaneously. Can happen.
In this case, since the time for the wiper to pass through the detection surface D is very short, the time required for the four wiper output values to change simultaneously and the time required for the wiper to pass through the detection surface are as follows. By comparing with a predetermined threshold value set based on this, it is possible to distinguish whether the change in each of the detection surfaces Da to Dd is due to the passage of the wiper or the splash.

For example, as shown in FIG. 5 (b), when it is confirmed that four output values for each of the detection surfaces Da to Dd fluctuate simultaneously in two ranges indicated by T1 and T2, the duration time Is longer than the above-mentioned predetermined threshold, it is splash, and when it is shorter, it is determined that the wiper has passed.
Incidentally, in the case of FIG. 5B, since the duration of the range indicated by T1 is shorter than the predetermined threshold, it is determined that the fluctuation of the output value in this range is due to the passage of the wiper, and the range indicated by T2 Is longer than a predetermined threshold value, and is determined to be due to splash.
Here, the predetermined threshold is set to a time slightly longer than the time required for the wiper to pass through the detection surface D when the wiper is driven at a low speed.

Incidentally, when only the output value from any one of the light receiving elements fluctuates, for example, as indicated by the symbol α in FIG. 5A, the output value from the light receiving element 12 that receives the reflected light from the detection surface Dd. In such a case, it can be determined that the change in the output value is due to raindrops.
Therefore, the relationship between the number of detection surfaces where such a change is detected and the time (detection time) when the change is detected and the cause of the change in the detection surface is defined in advance in the cause map.

  Therefore, when the cause determination unit 50 specifies the number of detection surfaces in which a change is detected and the detection time (number of blocks) of the change, the cause map is based on the specified number of detection surfaces and the detection time. The cause of the change is determined with reference to the MP.

Based on the determination result in the cause determination unit 50, the rainfall state estimation unit 60 includes a range indicating a change due to passage of a wiper, a range indicating a change due to splash, and a raindrop in a waveform indicating a change over time of the output of the light receiving element 12. It distinguishes from the range which shows other than the change by the passage of the wiper, such as the range which shows the change by the adhesion of the wiper.
And a rain condition is estimated based on the remaining range except the range which shows the change by the passage of a wiper, and the wiping signal which prescribes | regulates the operation | movement of a wiper according to an estimation result is produced | generated.
The wiper control unit 70 controls the wiper by operating the wiper motor with a drive signal generated based on the wiping signal input from the rain state estimation unit 60.

Processing in the cause determination unit of the wiper control device will be described.
FIG. 6 is a flowchart illustrating a process performed by the cause determination unit of the wiper control device based on change information generated by the change detection unit every time the wiper performs a single wiping operation.
In addition, the process in the wiper control apparatus 1 demonstrated using this flowchart is a process in case the number of the detection surfaces D set to the windshield glass G is four (refer FIG. 2).

In step 101, when the change information is input from the change detection unit 40, the cause determination unit 50 confirms whether or not the wiper is being driven based on an A / S signal input from a wiper motor (not shown). To do.
When the wiper is being driven in step 101, in step 102, the cause determination unit 50 divides the output of the light receiving element 12 into blocks, and there is a block including a detection surface in which a change is detected. It is confirmed with reference to the change information whether or not there are four or more blocks including the detected detection surface. That is, it is confirmed whether or not the change continues for 4 blocks or more.

  In step 102, when there is a block including a detection surface that has changed, and there are four or more blocks including a detection surface in which a change has been detected, in step 103, the cause determination unit 50 determines that the cause map With reference to MP, it determines with the cause of the change of the detection surface in these blocks being a splash (splash determination).

In step 102, when the change has not continued for four blocks or more, in step 104, the cause determination unit 50 determines that the number of detection surfaces having changed in the block including the detection surface in which the change is detected is four. Check if it exists.
When the number of detection surfaces that have changed in step 104 is four, in step 105, the cause determination unit 50 refers to the cause map MP and changes the detection surfaces in the block including the detection surface that has changed. It is determined that the cause of this is the passage of the wiper (wiper determination).
When the number of detection surfaces that have changed in step 104 is less than four, in step 106, the cause determination unit 50 checks whether or not the number of detection surfaces that have changed is one.

When the number of detection surfaces that have changed in step 106 is one, in step 107, the cause determination unit 50 refers to the cause map MP and changes the detection surfaces of the blocks including the detection surfaces that have changed. It is determined that the cause of this is the attachment of raindrops (raindrop determination).
On the other hand, when the number of detection surfaces that have changed is not one, in step 108, the cause determination unit 50 holds the determination (hold determination).
The processing from step 104 to step 108 includes several detection surfaces in which a change is detected for each of the blocks including a detection surface in which a change has been detected, for which the splash determination has not been made in the processing in step 102. The cause of the change is determined based on what is being done.

When the wiper is not being driven in step 101, the cause determination unit 50 refers to the change information in step 109, and there is a block including the changed detection surface, and includes the detection surface in which the change is detected. Check if the block continues for more than 4 blocks.
When there is a block including the detection surface that has changed in step 109 and there are four or more blocks including the detection surface in which a change is detected, in step 110, the cause determination unit 50 causes the cause map MP. Referring to FIG. 4, it is determined that the cause of the change in the detection surface in these blocks is splash (splash determination).
If the change does not continue for four blocks or more in step 109, it is determined in step 111 that the cause of the change in the detection surface in the block including the detection surface in which the change is detected is the attachment of raindrops (raindrop determination).

In step 112, the cause determination unit 50 outputs a determination result (wiper determination, splash determination, raindrop determination) to the rainfall state estimation unit 60.
Here, the determination of the cause of the change is performed on the output of the light receiving element 12 divided into blocks. Therefore, for example, when the output of the light receiving element 12 input within the period of one wiper wiping operation is divided into 60 blocks, block 1 to block 20 are raindrop determination, and block 21 to block 25. Is a wiper determination, block 26 to block 40 are raindrop determination, and so on, and a determination result having the content is generated and output to the rain state estimation unit 60.

At this time, if the determination that the cause of the change in the detection surface is the passage of the wiper (wiper determination) is made twice within the period of one wiper wiping operation, the hold determination is made in step 108 described above. If the cause of the change in the detected surface is handled as the passage of the wiper, there is a high possibility that the passage of the wiper is erroneously determined. Therefore, the cause determination unit 50 treats the cause of the change in the detection surface that has been determined to be on hold as being raindrop adhesion (raindrop determination) instead of passing through the wiper, and is raindrop determination even if it is determined to be on hold. Make a determination to that effect.
On the other hand, if it is determined that the wiper has passed less than two times within the period of one wiper wiping operation, it is highly likely that the wiper has been mistakenly judged as raindrop determination. Even if the determination is made, the determination result indicating raindrop determination is not output to the rainfall state estimation unit 60. Therefore, in this case, even if the hold determination is made, a determination result indicating raindrop determination is not output.
In this way, erroneous determination of wiper passage can be prevented.

Next, processing in the rain state estimation unit 60 of the wiper control device will be described.
FIG. 7 is a flowchart for explaining processing in the rain state estimating unit 60 of the wiper control device.
In step 201, the rainfall state estimation unit 60 checks whether or not the determination result input from the cause determination unit 50 is a splash determination.
When it is confirmed in step 201 that the determination result is a splash determination, in step 202, the rainfall state estimation unit 60 generates a splash signal.
When it is confirmed in step 201 that the determination result is not the splash determination, in step 203, the rainfall state estimation unit 60 confirms whether or not the determination result input from the cause determination unit 50 is raindrop determination.
When the determination result is raindrop determination in step 203, in step 204, the rainfall state estimation unit 60 shows a range indicating a change due to the passage of the wiper in a waveform indicating a change in the output of the light receiving element 12 with time. And the rain condition is estimated based on the rest of the range.

In step 205, the rain state estimation unit 60 determines whether or not wiping with a wiper is necessary based on the splash signal or the estimated rain state (wiping determination). If it is determined that wiping is necessary, the wiping condition (Wiping speed, operation mode) is determined.
At this time, it is preferable to determine the wiping condition in consideration of at least one of a wiper volume that finely adjusts the traveling speed of the vehicle and the wiping speed of the wiper.
In step 206, the rain state estimating unit 60 generates a wiping signal that commands driving of the wiper under the determined wiping condition, and outputs it to the wiper control unit 70.

For example, when the rain condition is estimated, it is determined that the current wiper wiping speed or operation mode needs to be changed as compared to the previously estimated rain condition, and the change is necessary. In this case, a new wiper wiping speed (high speed, medium speed, low speed) and an operation mode (continuous drive, intermittent drive) are determined so that the wiper can be driven appropriately according to the rain condition.
Further, when a splash signal is input, the wiper wiping speed is preferentially set to high speed and the operation mode is determined to be continuous driving so that wiping with the wiper is performed quickly.

  As a result, a wiping signal that defines the determined wiping speed and operation mode is generated and output to the wiper control unit 70. A drive signal to be driven is generated.

The distinction between a range corresponding to the passage of a wiper and a range corresponding to a splash or raindrop in a waveform indicating a change with time in the output of the light receiving element 12 will be described.
FIG. 8 is a diagram for explaining a distinction between a range corresponding to the passage of a wiper and a range corresponding to a splash or raindrop in a waveform indicating a change with time in the output of the light receiving element 12.

(A) superimposes and displays the output value of the light receiving element 12 for each of the detection surfaces Da to Dd, the vertical axis indicates the voltage value (mV), and the horizontal axis indicates time (seconds).
In (a), the appearance of the output values of the light receiving element 12 for each of the detection surfaces Da to Dd changing with time appears, and in the part surrounded by the ellipses indicated by reference signs A and B in the figure, The output values of the light receiving element 12 for all the detection surfaces Da to Dd vary greatly.

(B) and (c) superimpose and display the results when the change detection unit 40 confirms the temporal change in the output value of the light receiving element 12 for each of the detection surfaces Da to Dd.
In (b), the flag “1” is added to the portion of the change over time of the output value shown in FIG. The part that has not been displayed is displayed with a flag “0”. In (c), of the change over time of the output value shown in (a), the flag “1” is displayed and displayed on the portion determined to have fallen below the previous output value, and it has been judged that it has fallen. The part that has not been displayed is displayed with a flag “0”.

  Therefore, in the diagrams shown in (b) and (c), it is determined which part is an upward change and which part is the downward change in the waveform showing the change over time of the output value shown in (a). You can see if it was judged. For example, a portion surrounded by an ellipse indicated by reference symbol A1 in (b) and indicated by reference symbol A2 in (c) corresponds to a change in waveform of a portion indicated by reference symbol A in (a). It shows that there was an up and down change.

  (D) is a flag "" in the part determined by the cause determining unit 50 that the cause of the change is due to the passage of the wiper among the parts determined to have the upward change or the downward change shown in (b) and (c). 1 "is displayed. For example, in (d), the part enclosed by the ellipse indicated by symbol A3 is that the change in the part enclosed by the ellipse indicated by symbols A1 and A2 in (b) and (c) is a change caused by the wiper. Is shown.

  (E) is a part determined by the cause determination unit 50 that the cause of the change is caused by the splash (splash determination) among the parts determined to have the upward change or the downward change shown in (b) and (c). A flag “1” is attached and displayed. For example, in (e), the part surrounded by the ellipse indicated by reference numeral C3 is that the change of the part enclosed by the ellipses indicated by reference numerals C1 and C2 in (b) and (c) is a change caused by splash. Is shown.

  (F) indicates that the cause determination unit 50 determines that the cause of the change is due to the attachment of raindrops among the portions determined to have the upward change or the downward change shown in (b) and (c) (raindrop determination). The flag “1” is attached to the displayed part. Therefore, the part determined to be a change caused by the passage of the wiper shown in (d) from the part determined to have the upward change or the downward change shown in (b) and (c), and (e) It is shown that a portion substantially corresponding to a portion excluding a portion determined to be a change caused by splash is a change caused by raindrops.

  As described above, when the waveform indicating the change over time of the output of the light receiving element 12 after the digital conversion is, for example, a waveform as illustrated in FIG. 8A, the change detection unit 40 causes each detection surface D to be detected. Whether or not the output of the light receiving element 12 has changed is determined, and the cause determining unit 50 determines which part of the changed part is due to the passage of the wiper, is due to the splash, and is due to the attachment of raindrops. Is determined.

  Accordingly, in the waveform indicating the change over time of the output of the light receiving element 12, the range showing the fluctuation due to the passage of the wiper can be specified. Therefore, even if the raindrop is detected while the wiper is driven, the rainfall state estimating unit 60 The influence of the passage of the wiper on the estimation of the rain condition can be prevented, and the rain condition can be accurately estimated and reflected in the control of the wiper.

As described above, in this embodiment, light is emitted from the light emitting element 11 toward the plurality of detection surfaces D set in the wiper wiping region of the windshield glass G of the vehicle, and the light reflected by the detection surface D is received. The wiper control device 1 controls the wiper based on the rain condition estimated by receiving light by the element 12, and the plurality of detection surfaces D are set at positions where the passage of the wiper can be simultaneously detected. Based on the output, a change detection unit 40 that detects a change in each of the detection surfaces D, a cause determination unit 50 that determines the cause of the change based on the number of detection surfaces D in which the change is detected, and a cause of the change A configuration including a rainfall state estimation unit 60 that extracts fluctuations due to the wiper of the output of the light receiving element 12 and estimates the rainfall state from the output of the light receiving element 12 excluding the fluctuation of the output caused by the extracted wiper; It was.
Thereby, based on the number of detection surfaces D from which a change is detected, for example, when a change is detected on all the detection surfaces, the cause of the change in the detection surface D is a change due to the passage of the wiper. Is determined, and on the basis of the determination result, it is specified which part of the output of the light receiving element 12 that varies according to the amount of received light is the variation caused by the wiper.
Therefore, a portion caused by the wiper in the output of the light receiving element 12 can be distinguished from a portion based on a cause other than the wiper, for example, attachment of raindrops, so that detection of raindrops can be performed even when the wiper is operating. Since it can be performed for a long time, including during the wiper operation, raindrop detection can be performed stably.
Furthermore, since the rain condition is estimated from the output of the light receiving element 12 excluding the range showing the change due to the passage of the wiper, and the wiper is controlled based on the estimated rain condition, the rain condition is estimated and the wiper is controlled. It can be performed stably.

Further, the cause determination unit 50 determines the cause of the change in consideration of the time when the change is detected in addition to the number of detection surfaces where the change is detected.
Therefore, when changes are detected simultaneously on all of the detection surfaces of the plurality of detection surfaces D, whether the change is caused by the wiper by checking the detected time, or is caused by splash. Can be distinguished.
Therefore, changes that affect safety such as splash can be accurately detected and immediately reflected in the wiper control, thereby contributing to safe driving. Furthermore, since the wiper operation can be controlled while accurately measuring the change in rainfall, it is possible to prevent the wiper wiping operation from causing discomfort to the driver.
Further, since the number of detection surfaces D at which changes are simultaneously detected and the time at which the changes are detected can be confirmed, it is possible to distinguish between adhesion of raindrops and passage of the wiper, so that the wiper control device can be configured at low cost. Can be provided at.

Furthermore, the change detection unit 40 receives the output value of the light receiving element 12 for each detection surface D at regular intervals, and when the output value of the light receiving element 12 is input, the change detection unit 40 receives the output value of the light receiving element 12 input immediately before. Based on the difference, the change of each detection surface D is detected.
Thereby, the presence or absence of the change of the detection surface D can be easily confirmed only by calculating | requiring the difference with the output value input immediately before. In addition, since the output of the light receiving element 12 is input at predetermined intervals, the wiper control at the time of detecting the change of the detection surface D and the subsequent detection of raindrops as compared with the case where the output is input continuously. The processing burden on the apparatus can be reduced.

Further, the change detection unit 40 divides the output of the light receiving element 12 for each detection surface D input at regular intervals into blocks by dividing the output into a predetermined number of outputs that are continuous in the input order, and detects the detection surface in units of blocks. For example, when the change of the detection surface Da is detected from at least one of the outputs included in the first block, for example, the change of the detection surface Da is detected in the first block. The configuration was assumed to be.
As a result, for example, changes that occur simultaneously on all the detection surfaces Da to Dd due to the passage of the wiper are detected with a slight temporal shift and are not detected in the same sampling period. As long as the outputs are included in the sampling period, they are processed as detected at the same time. Therefore, it is possible to reliably detect a change in the detection surface that occurs at the same time, and to prevent the detection surface from being simultaneously detected due to a difference in the wiper wiping speed and the positional relationship between the detection surfaces.

Further, the change detection unit 40 is configured such that, for example, when a change in the detection surface Da is detected in one of the two adjacent blocks, a change in the detection surface Da is detected in both of the two adjacent blocks. did.
Thus, even if the change of the plurality of detection surfaces D due to the passage of the wiper is shifted by one block and confirmed separately over two blocks due to the division of the blocks or the like, two consecutive front and rear blocks (for example, In the first block and the second block), it is confirmed whether or not there is a change in each detection surface. If a change is confirmed only in one of the two adjacent front and rear blocks, It is assumed that a change has been confirmed even on the same detection surface. Therefore, it is possible to reliably detect changes that have occurred simultaneously on the four detection surfaces Da to Dd.

In addition, when a change is detected on the same detection surface D over a plurality of consecutive blocks, the change detection unit 40 determines the number of blocks in which the change is detected as the time when the change is detected. It was set as the structure to do.
Thereby, the time when the change is detected can be specified without requiring a complicated calculation.

In addition, the cause determining unit 50 refers to the cause map MP to determine the cause of the change. In the cause map MP, the change is divided into a case where the wiper is operating and a case where the wiper is stopped. The relationship between the number of detected surfaces and the time at which changes are detected and the cause of the change is specified, and the cause of the change includes at least the passage of wipers and the attachment of raindrops. .
As a result, it is possible to quickly determine whether the cause of the change in the detection surface is the passage of the wiper or the attachment of raindrops only by obtaining the number of detection surfaces in which the change has been confirmed.
Furthermore, since the cause of the change includes the action of water other than raindrops such as splash, for example, just by obtaining the number of detection surfaces where the change is confirmed and the time when the change is confirmed, It is possible to quickly determine whether the cause of the change in the detection surface is the passage of the wiper, the splash, or the attachment of raindrops.
Further, since the relationship defined in the cause map MP is divided into a case where the wiper is operating and a case where the wiper is stopped, more distinction is made between water other than raindrops (for example, splash) and raindrop adhesion. It can be done quickly and accurately.

  Further, in the cause map MP, a change is confirmed in all of the plurality of detection surfaces D, and the time when the change is confirmed is longer than a threshold value determined based on the time when the wiper passes the detection surface D. Sometimes the cause of the change is splash, and when it is short, it is defined that the wiper has passed. Further, when the wiper is operating, the change is confirmed on one of the detection surfaces D. If the period when the change is confirmed is shorter than the threshold determined based on the time when the wiper passes the detection surface, the structure is defined as the attachment of raindrops. By referring to the cause map MP based on the confirmed time, the cause of the change in the detection surface can be easily specified.

  In the above embodiment, the change detection unit 40 obtains the difference between the output value of the light receiving element 12 and the output value of the light receiving element 12 input immediately before, and detects the variation in the output of the light receiving element 12 for each detection surface D. Although it is configured to detect, the input output value of the light receiving element 12 is compared with a predetermined threshold value, and for example, when the output value of the light receiving element 12 is larger than the threshold value, it is determined that there is a change. Thus, a change in the output of the light receiving element 12 for each detection surface D may be detected. As a method based on comparison with this threshold value, for example, there is one disclosed in Japanese Patent Laid-Open No. 10-186059.

  In the above embodiment, the detection surface is changed as a cause of the wiper passing, raindrop adhesion and splash, but in addition to this, raindrops dripping on the windshield glass from the roof of the vehicle, etc. Alternatively, it may be detected as a cause of the change in the detection surface.

It is a block diagram of the wiper control device concerning an example. It is explanatory drawing explaining the structure of the sensor part of the wiper control apparatus concerning an Example. It is a figure explaining the determination of the presence or absence of the change of each detection surface It is a figure explaining a cause map. It is a figure explaining the output of the light receiving element after digital conversion. It is a flowchart explaining the process in the cause determination part of a wiper control apparatus. It is a flowchart explaining the process in the rain condition estimation part of a wiper control device. It is a figure explaining the distinction of the range corresponding to passage of a wiper in the output waveform of a light receiving element. It is a figure explaining the structure of the conventional raindrop sensor, and the detection principle of a raindrop. It is a figure explaining the relationship between the drive time of a wiper, and the detection period of a raindrop.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wiper control apparatus 10 Sensor part 11 Light emitting element 12 Light receiving element 13 Control board 14 Lens 20 Amplification part 30 Light reception amount detection part 40 Change detection part 50 Cause determination part 60 Rain state estimation part 70 Wiper control part D Detection surface G Windshield glass S water drop

Claims (11)

Based on the rainfall state estimated by irradiating light from the light emitting element toward a plurality of detection surfaces set in the wiper wiping region of the windshield glass of the vehicle and receiving the light reflected by the detection surface by the light receiving element A wiper control device for controlling a wiper,
The plurality of detection surfaces are set at positions where the passage of the wiper can be detected simultaneously,
A change detection unit that detects a change in each of the detection surfaces based on the output of the light receiving element;
A cause determination unit for determining the cause of the change based on the number of detection surfaces in which the change is detected;
It is characterized by comprising a rain condition estimation unit that extracts fluctuations due to the wiper of the output of the light receiving element based on the cause of the change and estimates the rain condition from the output of the light receiving element excluding the extracted fluctuation. Wiper control device for a vehicle.   The vehicle wiper control device according to claim 1, wherein the cause determination unit determines the cause of the change in consideration of a time during which the change is detected. The change detection unit receives the output of the light receiving element for each detection surface at regular intervals,
3. The vehicle wiper control device according to claim 2, wherein, when an output of the light receiving element is input, a change in each of the detection surfaces is detected based on a difference from an output input immediately before. The change detection unit divides the output of the light receiving element input at regular intervals into blocks divided into a predetermined number of outputs that are consecutive in the input order, and detects changes in the detection surfaces in units of blocks. With
4. The vehicle wiper control according to claim 1, wherein, when a change in the detection surface is detected from one of the outputs included in the block, the change in the detection surface is detected in the block. 5. apparatus. The change detection unit is characterized in that, when a change in a detection surface is detected in one of two adjacent blocks, a change in the detection surface is detected in both of the two adjacent blocks. Item 5. The vehicle wiper control device according to Item 4. When the change is detected on the same detection surface over a plurality of consecutive blocks, the change detection unit sets the number of blocks in which the change is detected as the time during which the change is detected. The vehicle wiper control device according to claim 4 or 5, characterized in that: 7. The cause of the change determined by the cause determination unit includes at least the passage of a wiper and the attachment of raindrops. 7. Vehicle wiper control device. The cause determination unit determines the cause of the change by referring to a cause map that defines the relationship between the number of detection surfaces where a change is detected and the time when the change is detected and the cause of the change. The vehicle wiper control device according to any one of claims 2 to 7. 9. The vehicle wiper device according to claim 8, wherein the relationship is set in the cause map separately when the wiper is operating and when the wiper is stopped. The cause of the change further includes the action of water other than raindrops,
In the cause map, when a change is detected in all of the plurality of detection surfaces, and a time during which the change is detected is longer than a threshold determined based on a time during which the wiper passes the detection surface. The vehicle wiper control device according to claim 8 or 9, characterized in that the cause of the change is an action of water other than raindrops, and when it is short, the wiper passes. In the cause map, when the wiper is operating, a change is detected on one of the plurality of detection surfaces, and a time during which the change is detected is a time during which the wiper passes the detection surface. The vehicle wiper control according to any one of claims 8 to 10, wherein the cause of the change is defined as raindrop adhesion when the threshold is determined based on apparatus.

Images