JPH0794217B2 - Wiper control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In a wiper control device that sets an intermittent time during which a wiper blade is driven according to an integrated value based on an output from a raindrop sensor, the calculation processing of the integrated value is important. .
In the present invention, raindrops adhering to the surface to be wiped are obtained by dividing the integrated value measured during the wiping operation of the wiper blade and the integrated value measured while the wiper blade is at rest. It is possible to determine the optimum integrated amount for the next wiper operation that reliably responds to rainfall such as, and thereby make the wiper operation start time almost coincide with the operation start time desired by the driver. It is possible to realize wiper control with good operation feeling.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiper control device that controls a wiping operation of a wiper blade based on a signal from a raindrop sensor that detects a rainfall state.

2. Description of the Related Art A so-called auto wiper device, which controls a wiper operation based on a detection signal from a raindrop sensor, integrates the detection signals from the raindrop sensor and starts the operation of the wiper when the integrated value exceeds a predetermined value. . As a means for accumulating the detection signals from the raindrop sensor, there has been a device for accumulating from the start of the wiper blade operation or the end of the operation.

FIG. 5 is a timing chart for explaining the operation of a typical prior art wiper control device that integrates the detection signals from the raindrop sensor at the same time when the wiper operation starts. FIG. 5 (1) shows a temporal change of the integrated value of the detection signal, and FIG. 5 (2) shows a temporal change of the wiping position of the wiper blade.

At time t11, when the integrated value reaches a predetermined threshold value THO, the wiper operation starts, and the wiper housed in the initial position starts operating. The integrated value is once cleared at the same time when the wiper operation is started, and the detection signals from the raindrop sensor are integrated again. Then, when the wiper blade reaches time t12, the wiper blade reaches the turning position, and at time t13, the wiper blade returns to the initial position again. Even if the wiper blade returns to the initial position, the detection signals from the raindrop sensor continue to be integrated and the time t14
At, the integrated value reaches the threshold value THO, and the wiper operation similar to the above is started again.

FIG. 6 is a timing chart for explaining the operation of another conventional wiper control device that integrates the detection signals from the raindrop sensor at the same time when the wiper operation is completed. Fig. 6 (1)
5 shows the temporal change of the integrated value of the detection signal from the raindrop sensor as in the case of FIG. 5, and FIG. 6 (2) shows the temporal change of the operating position of the wiper blade. The difference from the above-mentioned conventional example is that the accumulation of the detection signal from the raindrop sensor is started from time t23 when the wiper operation ends, and the wiper operation is performed at time t21 when the integrated value reaches the threshold value THO. It is started and the integration is not performed until time t23 when the initial position is reached via the turnaround position at time t22. And
The accumulation of the detection signals of the raindrop sensor starts at time t23, and the wiper operation starts again at time t24 when the integrated value reaches the threshold value THO.

5 and 6, it is assumed that the wiper blade moves at a constant speed and the amount of rainfall is constant.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The optimum timing for starting the wiper operation is when a certain amount of raindrops or the like adhering to the surface to be wiped reaches a certain amount and an obstacle occurs in the front field of view. Therefore, in the former conventional device, the raindrops detected from the time t11 to the time t12 are wiped off by the wiper operation during the period from the time t12 to the time t13, and therefore the integrated value of the period is calculated from the time t14. This is an unnecessary integrated amount for the wiper operation of. Time t1
Due to unnecessary integration in the period from 1 to time t12, the time to reach the integrated value threshold THO is shortened, and the driver feels that the wiper operation has started earlier.

In the latter conventional device, in the operating period from the initial position of the wiper blade to the folding position, the problem that the former has is solved in that the detection signal of the raindrop sensor is not integrated, but the wiper blade moves from the folding position. Since the detection signals during the period from time t22 to time t23 until returning to the initial position are not integrated, the driver feels that the start of the wiper operation is delayed. That is, it is necessary to integrate detection signals for raindrops that have adhered immediately after the wiper blade has been wiped during the period from when the wiper blade returns to the processing position to the processing position.

Therefore, the object of the present invention is to more accurately estimate the amount of objects to be wiped, such as raindrops, so that the start time of the wiper operation matches the operation start time more desired by the driver. To provide a wiper control device.

Means for Solving the Problems The present invention is a raindrop sensor for detecting a rainfall state, a wiper blade for removing an object to be wiped attached to a surface to be wiped, and a position detecting means for detecting a rest position of the wiper blade. A wiper drive unit that reciprocally drives the wiper blade on the surface to be wiped; and in response to an output of the position detection unit, the wiper blade starts moving from a rest position on the surface to be wiped, and then the rest position again. In the period until reaching, the first integrated value obtained by integrating the amount based on the output of the raindrop sensor and the amount based on the output of the raindrop sensor are integrated in a state where the wiper blade is in the rest position. And a second integrated value, and when the addition result exceeds a predetermined threshold value, a drive signal for operating the wiper blade is output to the wiper drive means. And a wiper control unit that applies force so that the gradient of the first integrated value is smaller than the gradient of the second integrated value for the same amount of raindrops output from the raindrop sensor. The wiper control device is characterized in that

Operation According to the wiper control device of the present invention, the raindrop sensor detects the rainfall state, and the wiper blade is controlled based on the output of the raindrop sensor. The wiper blade is driven by the wiper driving means, and reciprocally drives on the surface to be wiped to remove the object to be wiped adhering to the surface to be wiped. The rest position of the wiper blade on the surface to be wiped is detected by the position detecting means, and its output is given to the wiper control means. The wiper control means performs addition based on the first integrated value and the second integrated value.

The first accumulated value is a value obtained by accumulating the amount based on the output of the raindrop sensor in the period from when the wiper blade starts moving from the rest position on the surface to be wiped until it reaches the rest position again. The second integrated value is a value obtained by integrating the amount based on the output of the raindrop sensor when the wiper blade is in the rest position. When the addition result of the first integrated value and the second integrated value exceeds a predetermined threshold value, the wiper control means outputs a drive signal to the wiper drive means to operate the wiper blade.

Therefore, the calculated first integrated value and second integrated value are
Since each is calculated according to the amount of the wiped object that adheres, the time when the total integrated value as the addition result exceeds a predetermined threshold, that is, the time when the wiper operation starts matches the operation start time desired by the driver. Can be made.

Embodiment As an embodiment of the present invention, a wiper control device for wiping raindrops adhering to the windshield of an automobile will be described below. First, before explaining the configuration of one embodiment of the present invention,
The relationship between the operating position of the wiper blade and the raindrops, which are the objects to be wiped attached on the windshield, which is the surface to be wiped, will be described with reference to FIG.

FIG. 2 (1) shows the state immediately before the wiper operation, in which the wiper blade 20 located at the initial position starts moving in the direction of arrow Y1. Raindrops 21 are attached on the windshield between the wiper blade 20 located at the initial position and the folding position indicated by reference numeral 20a. Since the raindrops 21 are removed by the wiping operation of the wiper blade 20 onto the arrow Y1, the integrated value of the detection signal from the raindrop sensor while these raindrops 21 adhere to the windshield is compared with the next wiper operation. Should not be taken into consideration.

Next, FIG. 2 (2) shows the wiper blade 22 in the middle of returning from the folding position 22a to the initial position 22b, and the arrow Y2 indicates the moving direction of the wiper blade 22. In this state, raindrops 23 adhering between the wiper blade 22 and the initial position 22b
Is wiped when the wiper blade 22 returns to the initial position 22b, the integrated value of the raindrop sensor during the period when the raindrops 23 adhere is taken into consideration for the next wiper operation as in the case of FIG. 2 (1). should not do.

By the way, the raindrops 24 attached after the wiper blade 22 removes the raindrops are raindrops that are attached on the windshield until the next wiper operation starts, so the raindrop sensor detects the raindrops during the period in which the raindrops 24 are attached. The signals need to be integrated.

That is, the period in which raindrops that affect the wiper operation next time is from when the wiper blade passes the folding position, so the amount based on the detection signal of the raindrop sensor is integrated immediately after the wiper blade passes the folding position. As a result, although the amount of raindrops adhering to the windshield can be accurately defined, the wiper motor and the wiper control device which are usually used often do not output a signal for detecting the folding position. Further, the area where the raindrop sensor detects the rainfall state is relatively distant from the area where raindrops actually adhere to the windshield, and the detection accuracy of the raindrop sensor varies. In consideration of the above reason, the method of integrating the outputs from the raindrop sensor over the longest possible period and performing the processing according to the raindrop to be considered shown in FIG. 2 at the stage of the calculation process of the integrated value. However, it is considered that the amount of rainfall can be calculated with high accuracy.

Therefore, in this embodiment, it is utilized that the presence of the wiper blade in the rest position, which is the movement start position of the wiper blade and also the stop position after one reciprocating wiping operation, can be easily detected. That is, the wiper blade starts moving from the rest position, and in the period until returning to the rest position again, the integrated value accumulated based on the output from the raindrop sensor is multiplied by a coefficient of 1/4, and next time. Treated as an effective raindrop signal (first integrated value I1) for the wiper operation. After that, when the wiper blade is in a rest position at the rest position, the integrated value integrated based on the output from the raindrop sensor is directly treated as an effective raindrop signal (second integrated value I2), and the first Add to the integrated value I1,
The integrated value I required for the next wiper operation is calculated. In this way, since the integrated value I is calculated in consideration of the amount of raindrops while the wiper blade is operating and when it is stopped, the amount of raindrops adhering to the windshield can be accurately specified.

Next, the configuration of an embodiment of the wiper control device according to the present invention will be described. FIG. 1 is a block diagram showing an embodiment of a wiper control device according to the present invention. The wiper control circuit 1 performs so-called automatic wiper control in which the operation of the wiper is controlled based on the detection signal of the raindrop sensor 2. As the raindrop sensor 2, an optical type that detects the amount of raindrops passing between the light emitting and receiving elements, an electrostatic capacitance type that detects the amount of rain by detecting the change in capacity due to raindrops attached to the detection surface, or the energy of raindrops that collide with the detection surface. For example, a piezoelectric type that detects the amount of rainfall to detect the amount of rain is used. The detection signal of the raindrop sensor 2 is a waveform shaping circuit 3
The signal waveform is shaped, the noise component is removed, and the like, and then input to the processing circuit 4, which is realized by a microcomputer or the like. The wiper switch 5 is a switch for instructing the processing circuit 4 to perform auto wiper control, and the switch signal is input to the processing circuit 4 via the waveform shaping circuit 6 that removes noise components.

The power supply circuit 9 is a circuit that converts the voltage supplied from the battery 8 into a voltage used in the wiper control circuit 1.

When the wiper switch 5 is set to the conductive state, the automatic wiper control is started, and the processing circuit 4 outputs a drive signal for driving the wiper motor 10 to the drive circuit 11 based on the detection signal from the raindrop sensor 2. A wiper arm (not shown) is connected to the rotary shaft of the wiper motor 10, and the wiper blade reciprocates on the windshield as the wiper motor 10 rotates. A cam switch 12 is provided on the rotation shaft of the wiper motor 10, and when the rotation shaft of the wiper motor 10 rotates, the cam 13 also rotates. That is, the common contact Sa of the cam switch 12 is in conduction with the individual contact Sb when the wiper blade is in the rest position, while the common contact Sa is the common contact when the wiper blade is in operation and not in the rest position. The contact point Sa becomes conductive with the individual contact point Sc. The individual contact Sb is connected to the ground potential, and the individual contact Sc is connected to the battery 8. Therefore, the cam switch 12 functions as position detecting means, and by detecting the potential of the common contact Sa, it is possible to determine whether or not the wiper blade is in the rest position.

The processing circuit 4, based on the detection signal from the raindrop sensor 2,
The rotation speed of the wiper motor 10 is switched. That is, when the wiper blade is made to perform the intermittent operation or the low speed continuous operation, the low speed drive signal is output from the output terminal P1 of the processing circuit 4, and the drive circuit 11 causes the low speed input terminal 13 of the wiper motor 10.
Supply drive power to a. When the amount of rainfall increases and high-speed continuous operation is required, the processing circuit 4 outputs a high-speed drive signal from the output terminal P2, and the drive circuit 11 supplies drive power to the high-speed input terminal 13b. The terminal 13c of the wiper motor 10 is connected to the ground potential of, for example, the vehicle body.

The control of the processing circuit 4 when the wiper blade operates at a low speed will be briefly described below. First, when a low speed drive signal is output from the output terminal P1 of the processing circuit 4, the wiper motor 10 starts rotating and the wiper blade starts the wiping operation. At this time, the cam switch 12 moves from the conduction state of the common contact Sa and the individual contact Sb to the common contact Sa by the cam 13.
And the individual contact Sc are switched to the conductive state, and the potential of the common contact Sa becomes high level. After that, when the cam switch 13 further rotates and the common contact Sa and the individual contact Sb are brought into conduction, the potential of the common contact Sa becomes low level and the processing circuit 4
Stops the output from the output terminal P1. As a result, the wiping operation of the wiper blade stops, and the wiper blade stops at the initial position, that is, the rest position.

The control relating to the present invention in the wiper control device configured as described above will be described based on the timing chart of FIG.

FIG. 3 (1) shows a temporal change of the integrated value based on the detection signal from the raindrop sensor 2 in the processing circuit 4, and FIG.
FIG. 2B shows a temporal change in the operating position of the wiper blade.

At time t1 when the integrated value I based on the detection signal of the raindrop sensor 2 increases and reaches the threshold value TH, the processing circuit 4 causes the drive circuit 11 to operate.
The drive signal is sent to and the wiper operation starts. At the same time, the processing circuit 4 clears the integrated value I of the detection signal from the raindrop sensor 2 and then restarts the integration. In the present embodiment, during the period W13 from the time t1 to the time t3 at which the wiper blade passes through the folding position and returns to the rest position which is the initial position after the time t2, the detection signal of the raindrop sensor 2 remains unchanged. Instead of integrating, a value obtained by multiplying the detection signal by a predetermined coefficient is integrated.

That is, as described above, it is necessary to integrate only the raindrops attached after the wiping operation of the wiper blade in the period W13, and the amount of the attached raindrops is the sum of the detection signals of the raindrop sensor 2 accumulated in the time W13. Since it is considered to be approximately equal to 1/4, 1/4 is selected as the coefficient, and the value multiplied by the coefficient is measured as the first integrated value I1.

From the time t3, the wiper blade is in the rest state in the rest position for the intermittent time. Therefore, from the time t3, the detection signals of the raindrop sensor 2 are integrated as they are, the second integrated value I2 is measured, and the value obtained by adding the first integrated value I1 is required for the next wiper operation. Treat as value I. That is, the value obtained by integrating the detection signals of the raindrop sensor 2 in the period W34 starting from the time t3 in FIG. 3 is the second integrated value I2, and the value is sequentially added to the first integrated value I1 measured in the period W13. The second integrated value I2 is added, and the time W34 is continued until time t4 at which the integrated value I of the sums exceeds the threshold value TH. After that, at time t4, the integrated value I is cleared as at time t1, and the subsequent wiper operation is started. In the present embodiment, it is assumed that the moving speed of the wiper blade is constant and the amount of rainfall is constant.

Next, the processing executed in the processing circuit 4 will be described according to the flow chart shown in FIG. In the following explanation,
Except for step m1, the process from time t1 when the wiper starts operating will be sequentially described.

At step m1, initialization processing such as clearing the memory area or resetting the flag is performed. At step m2, it is determined whether or not the wiper is operating. That is, it is determined whether or not the common contact Sa of the cam switch 12 is at high level. At present, since the wiper has just started to operate, the process proceeds from step m2 to step m3, and the value of the timing counter C provided in advance is subtracted by +1 to update it, and the timing counter C is "0" at step m4. Determine whether or not. If the determination is negative, the process returns to step m2 and the above-described process is repeated. If the determination is positive, the process proceeds to step m5 and the timing counter C is set to the constant "4".
Is set, and the process proceeds to step m6.

In step m6, the detection signals from the raindrop sensor 2 are integrated, and it is determined whether or not the integrated value I integrated in step m7 is equal to or greater than a predetermined threshold TH. If the integrated value I is less than the threshold value TH, the process returns to step m2, and the steps m2 to m7 are repeated.

During the progress of the process, when the wiping operation of the wiper blade is completed, the determination in step m2 becomes negative, so the process proceeds from step m2 to step m6 until the integrated value I exceeds the threshold value TH. Is step m
Repeat step 2, m6 and then step m7.

That is, the process does not proceed to step m6 until the constant "4" set in the timing counter C in step m5 reaches "0" in step m4. In other words, the processes of steps m2 to m4 are repeated four times. If the wiper blade is performing the wiping operation, the detection signal from the raindrop sensor 2 is integrated at the timing of integrating the detection signal from the raindrop sensor 2 when the wiper blade is at rest. This is equivalent to 1/4 of the timing. Therefore, the first integrated value I1 accumulated through steps m2 to m7 is multiplied by a constant of 1/4 as compared with the second integrated value I2 accumulated through steps m2, m6, and m7. Is similar to.

After that, when the integrated value I becomes equal to or more than the threshold value TH in step m7, the process proceeds to step m8 to start the operation of the subsequent wiper, further clears the integrated value in step m9, and returns to step m2 again. The operation is repeated.

Therefore, according to the above-described embodiment, the first integrated value I1 that is integrated based on the output from the raindrop sensor during the wiping operation of the wiper blade and the raindrop sensor from the raindrop sensor while the wiper blade is in the idle state. Since the integrated value required for the next wiper operation is calculated according to the second integrated value I2 that is integrated based on the output of, the amount of raindrops adhering to the windshield is accurately specified. The operation start time of the wiper substantially coincides with the operation start time desired by the driver, and the wiper control with a good operation feeling can be realized.

Further, in this embodiment, the first integrated value I1 is changed to the second integrated value I2.
Although the description has been made in connection with the configuration in which the coefficient is multiplied by 1/4 as compared with
The configuration may be such that it is set to double, the first integrated value is directly integrated, and the second integrated value is multiplied by a constant of 4 to measure.

As described above, according to the present invention, the first integrated value measured during the operation of the wiper blade and the second integrated value measured during the rest of the wiper blade are attached to the surface to be wiped. By performing addition that is distinguished according to the amount of the wiped object,
The total amount of objects to be wiped on the surface to be wiped corresponds to the integrated value, and the wiper operation start time coincides with the operation start time desired by the driver, realizing a wiper control with a good operation feeling. it can.

In particular, according to the present invention, the slope of the first integrated value in the period from the start of movement of the wiper blade from the rest position to the return to the rest position is the slope of the second integrated value in the state where the wiper blade is at rest. The slope is smaller than the gradient, which makes it possible to accurately detect the amount of raindrops adhering to the surface to be wiped during the period in which the wiper blade returns from the folding position to the rest position.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a wiper control device according to the present invention, FIG. 2 is a diagram for explaining the relationship between the operation of the wiper and the attachment state of raindrops, and FIG. 3 is related to the present invention. Timing chart for explaining wiper operation, fourth
FIG. 5 is a flow chart for explaining the wiper operation according to the present invention, and FIG. 5 is a timing chart for explaining the operation of a conventional wiper control device that integrates the detection signal from the raindrop sensor at the same time when the wiper operation is started. The figure is a timing chart for explaining the operation of the conventional wiper control device that integrates the detection signals from the raindrop sensor at the same time when the wiper operation is completed. 1 ... Wiper control circuit, 2 ... Raindrop sensor, 10 ... Wiper motor, 11 ... Drive circuit, 12 ... Cam switch, 20 ...
… Wiper blade, 22b …… Rest position, 21,23, 24 …… Raindrop, TH …… Threshold

Claims (1)

[Claims] 1. A raindrop sensor for detecting a rainfall state, a wiper blade for removing an object to be wiped attached to a surface to be wiped, a position detecting means for detecting a rest position of the wiper blade, and the wiper blade A wiper driving unit that reciprocates on the surface to be wiped, and in response to the output of the position detection unit, the wiper blade starts moving from a rest position on the surface to be wiped and reaches the rest position again. A first integrated value in which an amount based on the output of the raindrop sensor is integrated, and a second integrated value in which the amount based on the output of the raindrop sensor is integrated in a state where the wiper blade is in a rest position. And a wiper control means for outputting a drive signal for operating the wiper blade to the wiper drive means when the addition result exceeds a predetermined threshold value. The first integrated value and the second integrated value are integrated such that the slope of the first integrated value is smaller than the slope of the second integrated value for the same amount of raindrops output from the raindrop sensor. Characteristic wiper control device.