JP2009023451A - Wiper control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiper control device capable of suppressing switching of a wiping mode caused by momentary fluctuation of a raindrop adhesion state to a detection region Ad of a raindrop sensor so as to achieve stable wiping operation by a wiper. <P>SOLUTION: In the case where mode-down determination is made, raindrop quantity R is measured when previous wiper stop time passes after start of next wiper stop time, and based on the measurement result, wiping mode determination is made again. When the raindrop quantity R is a first threshold K1 or larger, a wiper motor 11 is driven immediately to make the wiper 13 perform wiping operation, and mode-up determination is made to perform mode-up operation to shift to the previous wiping mode selected before the mode-down determination is performed. Thus, this can prevent a phenomenon of switching of the wiping mode due to fluctuation of adhesion of raindrops to the detection region Ad of the raindrop sensor 20 when a rainfall state is unchanged, so as to prevent a driver from feeling that the movement of the wiper 13 is unstable. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wiper control device that drives and controls a wiper that wipes a windshield glass based on a detection result of a raindrop sensor that detects raindrops attached to the windshield glass, and is suitable for use in an automobile or the like. .

  The wiper control device is mounted on, for example, an automobile, and when the wiper operation switch is switched to the automatic control mode (Auto mode) by the driver's operation, the wiper control device is based on the detection result of the raindrop sensor that detects raindrops. A wiping mode is set and the wiper is driven and controlled accordingly.

Conventional wiper control devices include, for example, a raindrop sensor, a wiper, a wiper driving device that moves the wiper, a controller, and the like. The controller measures the amount of raindrops by integrating the raindrop signal detected by the raindrop sensor during the wiper's reciprocating wiping interval, that is, during the wiper stop period, and measuring the amount of raindrops based on this raindrop amount. A wiping mode which is a wiping operation interval time is determined, and the wiper driving device is operated. The controller performs mode down to switch to a wiping mode in which the wiper reciprocating wiping operation interval time is longer when the raindrop amount is smaller than the first threshold, and when the raindrop amount is larger than the second threshold, the reciprocating wiping operation interval of the wiper. The mode is switched to the wiping mode with a shorter time, and when the raindrop amount is not less than the first threshold and not more than the second threshold, the wiping mode selected at that time is maintained (see Patent Document 1).
Japanese Patent No. 2661171

  The raindrop sensor used in the conventional wiper control device described above is attached to a windshield glass of an automobile and is miniaturized so as not to obstruct the driver's view. That is, in the conventional wiper control device, the raindrop adhesion state of the entire windshield glass is inferred based on the raindrop adhesion state on the detection area Ad of the raindrop sensor which is much smaller than the entire area of the windshield glass. During actual rain, the raindrop adhesion state on the windshield glass, that is, the raindrop distribution is not uniform. In particular, when the amount of rainfall is small, there is a possibility that the raindrop adhesion state on the detection area Ad of the raindrop sensor does not necessarily match the raindrop adhesion state in the entire windshield glass. Moreover, even if the raindrops adhere to the windshield glass for a long period of time, for example, about 10 minutes, even if the way of descending does not change, the strength of the way of descending may change instantaneously. For this reason, when the wiper wiping operation is controlled based on the raindrop detection signal from the raindrop sensor, the wiper control device wipes the wiper even though the driver does not feel that the rainfall state has changed. The mode may be changed, for example, the wiper wiping operation interval time may be switched. Hereinafter, an example of such a phenomenon will be described.

  The operation of the conventional wiper control device will be described based on the timing chart of the wiper wiping operation shown in FIG. FIG. 7A is a timing chart showing the time transition of the wiper operation, and FIG. 7B is a timing chart showing the time transition of the raindrop amount detected by the raindrop sensor. In FIG. 7, the wiper control device drives a wiper motor, which is a wiper drive device, at a reciprocating wiping operation interval time Tx. The wiper control device sets the next wiping mode, that is, the reciprocating wiping operation interval time of the wiper, based on the raindrop amount detected in the wiping operation interval time Tx that is the wiper stop time.

  In FIG. 7, the amount of raindrop detected each time is not less than the first threshold value K1 and not more than the second threshold value K2. In FIG. 7, the wiping mode in which the wiper reciprocating wiping operation interval time is time Tx is selected. ing.

  Here, although the rainfall state does not change, the detected amount of raindrops becomes smaller than the first threshold value K1 at time t1. This is because the magnitude of the detection signal from the raindrop sensor changes due to, for example, a change in the raindrop direction due to the wind. Thereby, the wiper control device determines the mode down to the time Ty that is longer than the previous time Tx, and sets the wiper's reciprocating wiping operation interval time from time t2 as time Ty. did. At this time, since the method of raining, that is, the rainfall density does not change, the amount of raindrop detected at time t3 after time Ty has elapsed from time t2 exceeded the second threshold value K2, as shown in FIG. Accordingly, the wiper control device determines the mode up to the time Tx that is one step shorter than the time Ty determined by the mode down for the next wiper reciprocating wiping operation interval time, and the wiper reciprocating wiping operation interval from time t4. Time was defined as time Tx. After time t4, the amount of raindrops detected after the wiper's reciprocating wiping operation interval time Tx has elapsed since the wiper stopped is stable at a first threshold value K1 or more and a second threshold value K2 or less, and the wiper control device The wiping mode in which the reciprocating wiping operation interval time is time Tx is maintained.

  In summary, while the wiper is operating at the wiping operation interval time Tx, the wiping operation interval time is changed to T2, that is, the wiper stop time is longer than T1, and then the wiper is again at the wiping operation interval time Tx. It is operating.

  From the viewpoint of the driver, it seems that the wiper wiping operation interval time has changed, although it does not feel that the rain has changed. That is, the wiper wiping operation may be felt unstable.

  As a means for solving such a problem, for example, it is conceivable to reduce the first threshold value K1. The first threshold value K1 is also an adjustment variable for enabling the driver to adjust the wiping mode switching sensitivity according to his / her preference in the wiper automatic control mode, and is difficult to change. It is also conceivable to increase the second threshold value K2. However, when the second threshold value K2 is increased, it is difficult to execute the wiping mode up, and the driver may feel that the windshield glass is not sufficiently wiped by the wiper.

  The present invention has been made in view of the above-described problems. When the wiper control device is operating in the Auto mode, the wiping mode is switched by instantaneous fluctuation of the raindrop adhesion state on the detection area Ad of the raindrop sensor. An object of the present invention is to provide a wiper control device that can suppress and perform a wiper wiping operation with a sense of stability.

  In order to achieve the above object, the present invention employs the following technical means.

  According to a first aspect of the present invention, there is provided a wiper control device comprising: a wiper; a wiper driving device that moves the wiper; and a raindrop signal corresponding to a raindrop amount attached to a detection region set within a wiper wiping range on the windshield. And a controller that controls the wiper driving device based on the raindrop signal when the raindrop signal is input from the raindrop sensor, and the controller is configured to operate during the wiper stop period, which is the interval between wiper reciprocating wiping operations. The detected raindrop signal is integrated to measure the raindrop amount, and the wiping mode that is the next reciprocating wiping operation interval time is determined based on the raindrop amount. When the raindrop amount is smaller than the first threshold, the controller When the raindrop amount is larger than the second threshold value, the wiper's reciprocating wiping is performed. It is a wiper control device that performs a mode up to switch to a wiping mode with a shorter operation interval time and maintains the wiping mode selected at that time when the raindrop amount is not less than the first threshold and not more than the second threshold. When the controller determines the mode down based on the amount of raindrops, the controller determines the period from the beginning of the wiper stop period until the end of the reciprocating wiping operation interval time immediately before the mode down during the first wiper stop period. Measure the intermediate raindrop amount, which is the raindrop amount obtained by integrating the detected raindrop signal, and maintain the selected wiping mode if the intermediate raindrop amount is less than or equal to the first threshold value. When larger than the first threshold value, the wiper driving device is immediately executed to perform the wiper wiping operation and the mode is increased.

  The wiper stop period after the mode-down determination is made by the controller is longer than the wiper stop period in the new wiping mode that is mode-down, that is, the wiper stop period before the mode-down determination. In other words, the time during which the raindrop amount measurement is performed becomes longer. In the above configuration, in the first wiper stop period after the mode-down determination, the controller does not integrate the raindrop signals detected until the end of the wiper stop period, but until the middle of the wiper stop period, that is, the wiper. The amount of intermediate raindrops is measured by integrating the raindrop signals detected during the period from the beginning of the stop period to the elapse of the reciprocating wiping operation interval time immediately before the mode down. The controller then performs the next wiping mode determination based on the amount of intermediate raindrops. That is, the selected wiping mode is maintained when the amount of intermediate raindrops is less than or equal to the first threshold value, and when the amount of intermediate raindrops is greater than the first threshold value, the wiper drive device immediately executes the wiper wiping operation and the mode is increased. I do.

  The effect of performing such control will be described.

  First, when the amount of intermediate raindrops is equal to or less than the first threshold, the amount of intermediate raindrops at this time is equivalent to the amount of raindrops during the wiper stop period in which the mode down determination is made. That is, that is, the amount of raindrops measured in the same detection period is the same, and this can be considered that the rainfall state has changed to the low rainfall amount side. Therefore, by maintaining the selected wiping mode, that is, the mode-down wiping mode, a wiper operation adapted to the raindrop adhesion state on the windshield glass can be obtained. On the other hand, when the amount of intermediate raindrops is larger than the first threshold, the amount of intermediate raindrops at this time is equal to the amount of raindrops in the wiper stop period immediately before the wiper stop period in which the mode down determination is made. In other words, the rainfall state has not changed, and the amount of raindrops measured during the wiper stop period when the mode-down determination is made is the mere raindrop adhesion variation in the detection area of the raindrop sensor, or instantaneous raindrop attachment due to wind etc. This is due to variations. Therefore, if the controller immediately causes the wiper driving device to execute the wiper wiping operation and performs mode up, the wiper stop period immediately after the mode down determination becomes the same as the wiper stop period before the mode down determination. Although the determination is made, the mode down is not actually executed. That is, when viewed from the driver, it is felt that the wiper wiping operation is continuously performed in the same wiping mode.

  As described above, when the wiper control device is operating in the Auto mode, the wiper wiping operation with a sense of stability is suppressed by suppressing the wiping mode switching due to the instantaneous fluctuation of the raindrop adhesion state to the detection area Ad of the raindrop sensor. It is possible to provide a wiper control device capable of achieving the above.

  Hereinafter, an embodiment of a wiper control device according to the present invention will be described with reference to FIGS. 1 to 5, taking as an example a case where it is applied to a wiper control device 1 mounted on an automobile.

(First embodiment)
The wiper control device 1 is mounted on the automobile 100 and controls the operation of the wiper device 10 that wipes raindrops adhering to the front windshield 101 in accordance with the operation position of the wiper control switch 30. In particular, when the automatic control (AUTO mode) position is selected in the wiper control switch 50, the amount of raindrops attached to the front windshield 101 is detected by the raindrop sensor 20, and the operation control of the wiper device 10 is performed based on the determination result. Do.

  First, the overall configuration of the wiper control device 1 will be described.

  As shown in FIG. 1, the wiper control device 1 is a controller that drives the wiper device 10 based on a raindrop sensor 20, a wiper device 10, a wiper control switch 30, a signal from the wiper control switch 30 and a signal from the raindrop sensor 20. It consists of a microcomputer 50 or the like. The wiper control device 1 is supplied with electric power from an automobile battery (not shown) via an automobile ignition switch (not shown).

  A wiper and a wiper device 10 as a wiper driving device for driving the wiper convert a driving torque generated by the wiper motor 11, a wiper 13 that performs a reciprocating wiping operation on the front windshield 101 into a reciprocating motion, and a wiper. 13 and a link mechanism 12 that reciprocates the wiper 13. The reciprocating wiping operation of the wiper 13 is executed by outputting a drive instruction signal to the wiper motor 11 from the wiping mode determination unit 51 provided in the microcomputer 50.

  The wiper control switch 30 is installed in the driver's seat in the automobile, and is used to stop the reciprocating wiping operation of the wiper 13 (OFF mode), automatic control (AUTO mode), low speed operation (LO mode), and high speed operation (HI mode). The switch function is switched by manual operation of the driver. The wiper control switch 30 is rotated to any one of four operating positions, for example, so that one of these operation modes is selected. When one of the four operation modes described above is selected, the wiper control switch 30 outputs information about the selected operation mode to the microcomputer 50 (wiping mode determination unit 51) described later.

  As shown in FIG. 3, the raindrop sensor 20 basically includes a light emitting element 21 such as a light emitting diode that emits infrared light toward the detection region Ad of the front windshield 101, and the light emitting element 21. And a light receiving element 22 such as a photodiode that outputs an output value corresponding to the amount of light received and reflected by the front windshield 101. The light emitting element 21 is connected to the microcomputer 50 through a light emitting element driving circuit (not shown), and the microcomputer 50 controls the turning on / off of the light emitting element 21. The light receiving element 22 is connected to the microcomputer 50 via a detection amplification circuit (not shown), and outputs a detection signal corresponding to the detected amount of raindrops to the microcomputer 50. With this configuration, when no raindrop is attached to the detection area Ad, the infrared light emitted from the light emitting element 21 travels as indicated by the solid line arrow in FIG. Most of the light is reflected by the front windshield 101 and received by the light receiving element 22. However, when the raindrop D is attached to the detection area Ad, a part of the infrared light emitted from the light emitting element 21 is broken by the broken line in FIG. 3 via the raindrop D attached to the detection area Ad. It proceeds as indicated by the arrow and exits from the front windshield 101. Therefore, the amount of light received by the light receiving element 22 is reduced. As described above, the amount of raindrops adhering to the detection region Ad is optically detected based on the amount of raindrops adhering to the detection region Ad and the amount of light received by the light receiving element 22. In the raindrop detection apparatus 1 according to the first embodiment of the present invention, the detection signal of the raindrop sensor 20 decreases as the amount of raindrops adhering to the detection area Ad increases, and the raindrop sensor 20 decreases as the amount of raindrops adhering to the detection area Ad decreases. The detection signal becomes larger.

  The microcomputer 50 as a controller is actually a memory including a CPU that performs control processing and arithmetic processing, and a memory such as a read-only memory (ROM) and a writable memory (RAM) for storing various programs and data. It is configured to include functions of an input circuit such as a device, an AD converter, an output circuit, and a power supply circuit. However, here, as shown in FIG. 2, a rainfall amount determination unit 52 that determines the amount of raindrops attached to the front windshield 101 based on the magnitude of a change in the detection signal output from the raindrop sensor 20, a rainfall amount determination unit A wiping mode determination unit that determines the wiping mode related to the wiper 13 operation based on the rainfall determined in 52, that is, determines the reciprocal wiping operation interval time of the wiper 13 and outputs a drive signal to the wiper motor 11 based on the wiping operation interval time. The concept will be described with a focus on 51.

  The wiping mode determination unit 51 takes in information on the current rainfall situation from the raindrop amount determination unit 52 and information on the operation mode from the wiper control switch 30, and drives and controls the wiper motor 11 based on these information. That is, when the wiper control switch 30 is operated to stop the wiping operation (OFF mode), to operate at a low speed (LO mode), and to operate at a high speed (HI mode), the wiping mode determination unit 51 receives it and performs a predetermined drive. An instruction signal is output to the wiper motor 11. On the other hand, when the wiper control switch 30 is operated to automatic control (AUTO mode), the wiping mode determination unit 51 is based on the rainfall determined by the rainfall determination unit 52 based on the detection signal from the raindrop sensor 20. The wiping mode by the wiper 13, that is, the reciprocating wiping operation interval time by the wiper 13 is determined, and a drive instruction signal corresponding to the determined wiping mode is output to the wiper motor 11. When the microcomputer 50 performs automatic control, the wiping mode determined by the microcomputer 50, that is, the reciprocating wiping operation interval time by the wiper 13, is 7.0 seconds, 3.3 seconds, and 1.5 seconds in order from the longest. Second, 0.6 seconds. The above four wiping mode is a so-called intermittent mode in which the stop time between the reciprocating wiping operations of the wiper 13 is clearly recognized by the driver. In automatic control, a stop mode, a low speed mode, and a high speed mode are selected in addition to these. The low speed mode and the high speed mode differ in the rotational speed of the motor 11, that is, the moving speed of the wiper 13. The low-speed mode and the high-speed mode appear to be continuously operated from the driver, but actually there is a short stop time between the reciprocating wiping operations of the wiper 13 as in the four wiping modes described above. .

  Next, the operation of the wiper control device 1, particularly the wiping mode determination method in the wiping mode determination unit 51 of the microcomputer 50 when the wiper control switch 30 is operated in automatic control (AUTO mode) is shown in FIG. Description will be made with reference to a timing chart shown in FIG. 4A shows the time transition of the operating state of the wiper motor 11, that is, the operating state of the wiper 13, and FIG. 4B shows the time transition of the raindrop amount R measured based on the detection signal of the raindrop sensor 20. It is a timing chart shown respectively.

  The measurement of the raindrop amount by the rainfall amount determination unit 52 of the microcomputer 50 is performed within the reciprocal wiping operation interval time Tp by the wiper 13, that is, during the stop period Tp of the wiper 13. When the wiper 13 passes through the detection area of the raindrop sensor 20 and stops, all the raindrops attached on the detection area of the raindrop sensor 20 are wiped off. Then, when the wiper 13 stops, measurement of the raindrop amount by the rainfall amount determination unit 52 is started. At the same time, raindrops newly adhere to the detection area of the raindrop sensor 20. The amount of raindrops adhering to the detection area of the raindrop sensor 20 increases with time as shown in FIG. Then, the wiping mode determination unit 51 of the microcomputer 50 determines the next wiping operation mode, that is, the next reciprocating wiping operation interval time Tn by the wiper 13 based on the raindrop amount R at the time when the stop period Tp of the wiper 13 has elapsed. decide. When the raindrop amount R at the time when the stop period Tp of the wiper 13 has elapsed is the raindrop amount R1 that is less than the first threshold value K1, the wiping mode determination unit 51 determines that the reciprocating wiping operation interval time of the wiper 13 is one step longer than the time Tp. The wiping mode is determined, and the next reciprocating wiping operation interval time Tn1 is determined. On the other hand, when the raindrop amount R is equal to or greater than the second threshold K2 when the stop period Tp of the wiper 13 has elapsed, the wiping mode determination unit 51 determines that the reciprocating wiping operation interval time of the wiper 13 is longer than the time Tp. The next shorter wiping mode is determined, and the next round-trip wiping operation interval time Tn3 is determined. When the raindrop amount R is equal to or greater than the first threshold value K1 and less than the second threshold value K2 when the stop period Tp of the wiper 13 has elapsed, the wiping mode determination unit 51 selects the currently selected wiping mode. Determination is made and the next reciprocating wiping operation interval time Tn of the wiper 13 is set to the same time Tp as the current time. And the wiping mode determination part 51 drives the wiper motor 11 simultaneously with determining the next wiping mode, and performs the wiping operation | movement by the wiper 13. FIG.

  By repeating the raindrop amount measurement and the wiping mode determination as described above, the wiper control device 1 always moves the wiper 13 in the wiping mode corresponding to the rainfall amount, and wipes the raindrops adhering to the front windshield 101 to operate. The front view of the person is secured.

  Next, an automatic wiper control process executed in the microcomputer 50 of the wiper control device 1 configured as described above will be described with reference to FIG. FIG. 5 is a flowchart showing a specific processing procedure of the wiper motor drive control process executed by the microcomputer 50.

  When the automatic control (AUTO mode) is selected through manual operation of the wiper control switch 30 by the driver of the automobile, the wiper automatic control process shown in FIG. 5 is started. When this process is started, the microcomputer 50 first executes the initialization process of step 101.

  Subsequently, in step 102, the microcomputer 50 determines whether or not the wiper 13 is performing a wiping operation. If the wiper 13 is in the wiping operation as a result of this determination processing, the raindrop amount data is erased in the next step 103. On the other hand, if the wiper 13 is not in the wiping operation, the raindrop amount is measured in step 104.

  Subsequently, in step 105, the microcomputer 50 determines whether the operation of the wiper device 1, that is, the drive instruction signal output from the wiping mode determination unit 51 to the wiper device 10 is the wiping mode, that is, the mode for driving the wiper motor 11. Then, it is determined whether the stop mode is set. If the result of this determination process is the stop mode, the subsequent step 106 compares the amount of raindrops measured in step 104 with the first threshold value K1. On the other hand, when in the wiping mode, in step 109, the magnitude of the raindrop amount measured in step 104 is compared with the second threshold value K2.

  As a result of comparing the amount of raindrops in step 106 with the first threshold value K1, if the raindrop amount is larger than the first threshold value K1, the intermittent mode as the wiping mode, that is, the mode in which the reciprocating wiping operation interval time by the wiper 13 is the longest, In the wiper control device 1 according to the embodiment of the present invention, the reciprocating wiping operation interval time is set to 7.0 seconds, and then the wiper motor 11 is driven in step 108 to cause the wiper 13 to perform the reciprocating wiping operation. The control after step 102 is repeated. On the other hand, if the amount of raindrop is smaller than the first threshold value K1 as a result of the size comparison between the amount of raindrops and the first threshold value K1 in step 106, the control from step 102 is immediately repeated.

  If the driving instruction signal output from the wiping mode determination unit 51 to the wiper apparatus 10 is the wiping mode as a result of the determination in the previous step 105, the raindrop amount measured in step 104 and the second threshold value K2 are determined in step 109. Compare size with. If the result of determination in step 109 is that the amount of raindrops is greater than or equal to the second threshold value K2, the wiping mode determination unit 51 of the microcomputer 50 determines that the mode is up, and the reciprocating wiping operation interval by the wiper 13 is greater than before. Select a wiping mode that is shorter in time. Subsequently, in step 111, the wiper motor 11 is driven to cause the wiper 13 to perform a reciprocating wiping operation, and thereafter, the control in and after step 102 is repeated. On the other hand, if the result of determination in step 109 is that the amount of raindrops is less than the second threshold value K2, the process proceeds to step 112. In step 112, the intermittent time, that is, the wiper stop time has elapsed, or is still within the wiper stop time. Determine if there is.

  If the result of determination in step 112 is that the wiper stop time has elapsed, in subsequent step 113, the magnitude of the raindrop amount is compared with the first threshold value K1. If the result of determination in step 113 is that the amount of raindrops is greater than the first threshold value K1, the wiping mode determination unit 51 of the microcomputer 50 determines that the wiping mode is maintained, and in the subsequent step 116, the wiper motor 11 is driven to drive the wiper 13 The reciprocating wiping operation is performed, and then the control after step 102 is repeated. On the other hand, if the result of determination in step 113 is that the amount of raindrops is less than the first threshold value K1, the wiping mode determination unit 51 of the microcomputer 50 determines that the mode is down. In step 115, the wiping mode in which the reciprocating wiping operation interval time by the wiper 13 is longer than that of the currently selected wiping mode is selected. Subsequently, in step 116, the wiper motor 11 is driven to cause the wiper 13 to perform a reciprocating wiping operation, and then the control in and after step 102 is repeated.

  If the result of determination in step 112 is that it is within the wiper stop time, the routine proceeds to step 117, where it is determined whether or not the mode has been down from the previous wiping mode. If the result of determination in step 117 is that the mode has not been down from the previous wiping mode, the control from step 102 is immediately repeated. On the other hand, if the result of determination in step 117 is that the mode has been down from the previous wiping mode, it is determined in subsequent step 118 whether the reciprocal wiping operation interval time in the previous wiping mode has elapsed or not yet. If the result of determination in step 118 is that the reciprocal wiping operation interval time in the previous wiping mode has not elapsed, the control from step 102 is immediately repeated. On the other hand, if the result of determination in step 118 is that the reciprocal wiping operation interval time in the previous wiping mode has elapsed, then in step 119, the magnitude relationship between the raindrop amount and the first threshold value K1 is determined. If the result of determination in step 119 is that the amount of raindrops is less than the first threshold value K1, the control from step 102 is immediately repeated. On the other hand, when the raindrop amount is equal to or greater than the first threshold value K1, the wiping mode determination unit 51 of the microcomputer 50 determines that the mode is up, and in the subsequent step 120, the wiper 13 uses the wiping mode that is currently selected. The wiping mode in which the reciprocating wiping operation interval time is one step shorter, in other words, the previous wiping mode is selected. Subsequently, in step 121, the wiper motor 11 is driven to cause the wiper 13 to perform a reciprocating wiping operation, and then the control in and after step 102 is repeated.

  Next, the operation of the present embodiment will be summarized with reference to the timing charts shown in FIGS. 6 (a) to 6 (b). 6A shows the time transition of the operation state of the wiper motor 11, that is, the operation state of the wiper 13, and FIG. 6B shows the time transition of the raindrop amount measured based on the detection signal of the raindrop sensor 20. It is a timing chart which shows.

  In the explanation of this figure, it is assumed that the AUTO mode is selected through manual operation of the wiper switch by the user of the automobile, and automatic control of the wiper device 10 by the microcomputer 50 has already started.

  Under such a premise, the raindrop amount determination unit 52 of the microcomputer 50 measures the raindrop amount based on the detection signal from the raindrop sensor 20, and the wiping mode in which the wiping mode determination unit 51 is based on the raindrop measurement result. And the wiper device 10 is operating in the wiping mode. That is, as shown in FIG. 6, the wiper device 10 is operating in the intermittent wiping mode in which the reciprocal wiping operation interval time by the wiper 13 is the time Tx. It is assumed that the rain state at this time is so-called light rain, and the way of falling is stable without change. As shown in FIG. 6, the raindrop amount R measured at t10 is not less than the first threshold value K1 and less than the second threshold value K2, so that the wiping mode determination unit 51 of the microcomputer 50 determines the currently selected wiping mode. The wiping mode in which the time interval of the reciprocating wiping operation by the wiper 13 is the time Tx is selected and reflected in the next wiper stop time, that is, the wiper stop time starting from the time t11. The magnitude of the raindrop amount R measured at time t12 is the same, and the wiper stop time starting from time t13 is also set to time Tx. However, the raindrop amount R measured at time t14 is smaller than the first threshold value K1, as shown in FIG. This is because the area of the raindrop detection area of the raindrop sensor 20 is small, and the raindrop sensor 20 detects the detection signal from the raindrop sensor 20 due to the change of the raindrop direction due to the wind even though the rain does not change. This is due to the change in size. The wiping mode determination unit 51 of the microcomputer 50 determines that the raindrop amount R has fallen below the first threshold value K1, and thus determines that the mode is down, and the reciprocal wiping operation interval time by the wiper 13 is one step longer than the currently selected wiping mode. The wiping mode at T2 is selected, and the next wiper stop time, that is, the wiper stop time starting from time t15 is defined as time T2. At the same time, the wiping mode determination unit 51 of the microcomputer 50 measures the raindrop amount R at time t16 after the lapse of time Tx, which is the wiper stop time of the previous wiping mode, from time t15 when the mode is down. The raindrop amount R at this time is equal to or greater than the first threshold value K1, as shown in FIG. Therefore, the wiping mode determination unit 51 of the microcomputer 50 determines that the mode is up, and from the currently selected wiping mode, that is, the wiping mode in which the wiper stop time is time T2, to the wiping mode in which the one-step wiper stop time is shorter than that. That is, the wiping mode is switched to the wiping mode in which the wiper stop time is time Tx. At the same time, the wiping mode determination unit 51 of the microcomputer 50 outputs a drive signal to the wiper motor 11 at time t16 to cause the wiper 13 to perform a reciprocating wiping operation. The wiper stop time starting from time t18 is set to time Tx. After that, the manner of raining does not change, and the wiping mode determination unit 51 of the microcomputer 50 continues to maintain the wiping mode in which the time interval Tx of the reciprocating wiping operation by the wiper 13 is the currently selected wiping mode. .

  A feature of the wiper control device 1 according to an embodiment of the present invention is in the control of the wiping mode determination unit 51 of the microcomputer 50 after the time t14 in the description of the operation based on the timing chart described above. That is, when the mode down determination is made, the raindrop amount R is measured when the previous wiper stop time has elapsed since the start of the next wiper stop time, instead of maintaining the next wiper stop period. Then, the wiping mode determination is performed again based on the measurement result. That is, if the raindrop amount R is equal to or greater than the first threshold value K1, the drive signal is immediately output to the wiper motor 11 to cause the wiper 13 to perform the wiping operation, and the mode-up determination is made and selected in the previous mode-down determination. The wiping mode has been upgraded from the previous wiping mode. In other words, control is performed to cancel the previous mode down determination and return to the wiping mode before the mode down determination. Thereby, when the rainy state has not changed, the wiping mode is switched by the fluctuation of the raindrop adhesion to the detection area Ad of the raindrop sensor 20, and the driver feels that the movement of the wiper 13 is unstable. Can be prevented from occurring.

  The operation of the conventional wiper control device in which the above-described control is not performed will be described with reference to FIG. In this case, when the mode down determination is made at time t14, the next wiper stop time starting from t15 is set to time T2, and the wiper 13 is stopped until time t17. However, since the rainfall state does not change, the raindrop amount R to be measured increases as indicated by a broken line in FIG. 6, and when the wiping mode is determined by the wiping mode determination unit 51 of the microcomputer 50 at time t17, the raindrop amount R Exceeds the second threshold value K2, and as a result, the mode-up determination is made. Thereby, after the time t17, the wiping mode in which the wiper stop time is the time Tx is selected again, and the wiper 13 performs the wiping operation. That is, in the conventional wiper control device, the wiper wiping mode, that is, the wiper stop time changes from time Tx → time T2 → time Tx even though the rain condition does not change, and the driver is unstable in the operation of the wiper. I feel that.

  On the other hand, according to the wiper control device 1 according to the embodiment of the present invention, the raindrop adhesion state on the detection area Ad of the raindrop sensor 20 varies when there is no change in the raindrop state, and the detection signal from the raindrop sensor 20 is detected. Even if there is a fluctuation, the change of the wiping mode due to the fluctuation of the detection signal can be suppressed, and the wiping operation of the wiper 13 can be stabilized.

  In the above embodiment, the windshield on which the wiper control device 1 is installed has been described as the front windshield 101 in front of the driver seat. However, the windshield need not be limited to the front windshield 101, and other windows, for example, the rear windshield. You may apply to.

  Moreover, although the said embodiment mentioned the example which mounted the wiper control apparatus in the motor vehicle, the mounting place is not restricted to a motor vehicle. In addition, it is useful to be widely mounted on mobile objects such as airplanes, railway vehicles, and ships.

1 is a schematic diagram showing a state where a wiper control device 1 according to a first embodiment of the present invention is mounted on an automobile 100. FIG. 1 is a block diagram showing an overall configuration of a wiper control device 1 according to a first embodiment of the present invention. It is sectional drawing explaining the structure of the raindrop sensor 20, and is the III-III sectional view taken on the line in FIG. (A) is a timing indicating the time transition of the operating state of the wiper motor 11, that is, the operating state of the wiper 13, and (b) is a timing indicating the time transition of the raindrop amount R measured based on the detection signal of the raindrop sensor 20. It is a chart. It is a schematic diagram explaining the wiping mode setting process performed by the wiping mode determination unit 51 when the sensitivity correction switch 40 is switched. (A) is a timing indicating the time transition of the operating state of the wiper motor 11, that is, the operating state of the wiper 13, and (b) is a timing indicating the time transition of the raindrop amount R measured based on the detection signal of the raindrop sensor 20. It is a chart. It is a figure for demonstrating the action | operation in the conventional wiper control apparatus, (a) is a wiper motor operating state, ie, the time transition of the operating state of a wiper, (b) is measured based on the detection signal of a raindrop sensor. It is a timing chart which shows each time transition of the amount of raindrops made.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wiper control apparatus 10 Wiper apparatus 11 Wiper motor 12 Transmission mechanism 13 Wiper 20 Raindrop sensor 21 Light emitting element 22 Light receiving element 30 Wiper control switch 50 Microcomputer 51 Wiping mode determination part 52 Raindrop amount determination part 100 Car 101 Front windshield A Wiping area Ad Detection area (predetermined area)
D Raindrop R Raindrop amount T Wiping operation interval time

Claims (1)

A wiper, a wiper driving device that moves the wiper, a raindrop sensor that outputs a raindrop signal corresponding to the amount of raindrops attached to a detection area set within a wiper wiping range on a windshield, and a raindrop sensor A controller for controlling the wiper driving device based on the raindrop signal when a raindrop signal is input;
The controller integrates the raindrop signal detected during the wiper stop period which is the reciprocating wiping operation interval time of the wiper to measure the raindrop amount, and at the next reciprocating wiping operation interval time based on the raindrop amount. Determine a certain wiping mode,
The controller performs mode down for switching to a wiping mode in which the reciprocating wiping operation interval time of the wiper is longer when the raindrop amount is smaller than a first threshold, and when the raindrop amount is larger than a second threshold, the controller The mode is switched to the wiping mode in which the reciprocating wiping operation interval is shorter, and when the raindrop amount is not less than the first threshold and not more than the second threshold, the wiping mode selected at that time is maintained. Wiper control device,
When the controller determines the mode down based on the amount of raindrops, the controller performs the reciprocating wiping operation interval immediately before the mode down from the beginning of the wiper stop period during the first wiper stop period after the mode down determination. An intermediate raindrop amount, which is a raindrop amount obtained by integrating the raindrop signals detected in a period until time elapses, is measured, and is selected when the intermediate raindrop amount is equal to or less than the first threshold value. A wiper control device that maintains the wiping mode and causes the wiper driving device to immediately execute a wiper wiping operation and perform the mode up when the amount of intermediate raindrops is greater than a first threshold value.

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