JPH0338447A - Wiper controller - Google Patents

Abstract

PURPOSE:To align a start point for operating wipers to a driver's sense by a method wherein amounts of attached raindrops during wiper operation and idle periods are separately measured and calculation is done based on the amounts so that a driving signal is sent to a wiper driving means according to the calculation result. CONSTITUTION:A processing circuit 4 determines intermittent operation or high speed operation of wipers based on a signal detected by a raindrop sensor 2 to send a signal to a driving circuit 11. When a low speed driving signal is sent from an output terminal P1 of the processing circuit 4. A wiper motor 10 starts rotation. At this time a cam switch 12 switches from conductive state between a common contact Sa and a separate contact Sb to conductive state between a common contact Sa and a separate contact Cc by a cam 13 thereby raising potential of the common contact Sa. When the cam 13 further rotates and the common contact Sa and the separate contact Sb are in conductive state, the potential of the common contact Sa drops so that the processing circuit 4 stops the output to have wiper blades stop at rest position. When the amount of attached raindrops during the idle period reaches a predetermined value, the driving signal is again output from the processing circuit 4 to start intermittent operation corresponding to the amount of attached raindrops.

Description

[Detailed Description of the Invention] Overview 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, importance is placed on the arithmetic processing of the WX value. .

In the present invention, by calculating the integrated value measured during the wiping operation of the wiper blade and the integrated value measured while the wiper blade is not in use, raindrops etc. that adhere to the surface to be wiped can be reduced. It is possible to determine the optimal integrated value for the next wiper operation that reliably corresponds to the amount of rainfall, and this allows the wiper start time to approximately match the start time desired by the driver. Aiming to realize wiper control with good feel.

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

Conventional technology A so-called automatic wiper device that controls wiper operation based on a detection signal from a raindrop sensor integrates the detection signal from the raindrop sensor, and starts wiper operation when the integrated value exceeds a predetermined value. . As a means for aming the detection signal from the raindrop sensor, there has conventionally been a device that integrates the detection signal from the start or end of the wiper blade operation.

FIG. 5 is a timing chart for explaining the operation of a typical conventional wiper control device that integrates detection signals from raindrop sensors simultaneously with the start of wiper operation. FIG. 5(1) shows the temporal change in the integrated value of the detection signal, and FIG. 5(2) shows the temporal change in the wiping position of the wiper blade.

At time tll, when the integrated value reaches a predetermined threshold THO, the wiper operation starts, and the wiper housed in the initial position starts operating. At the same time as wiper operation starts, the integrated value is cleared once, and the detection signal from the raindrop sensor is integrated again.

Then, when the wiper blade reaches the time 'XJlt12, it reaches the return position, and returns to the initial position again at the time t13. Even when the wiper blade returns to its initial position, the detection signal from the raindrop sensor continues to be integrated, and at time t14, the integrated value reaches the threshold T)(O, and the wiper operation starts again in the same manner as described above.

FIG. 6 is a timing chart illustrating the operation of another conventional wiper control device that integrates the detection signal from the raindrop sensor at the same time as the wiper operation ends. Figure 6 (1
) shows the temporal change in the integrated value of the detection signal from the raindrop sensor in the same way as P4 in Fig. 5, and Fig. 6 (2>) shows the temporal change in the operating position of the wiper blade.The above-mentioned conventional example The difference is that the integration of the detection signal from the raindrop sensor starts from time t23, which is the end of wiper operation, and the integration value reaches the threshold THO at time t2.
1, the wiper fY movement starts, and integration is not performed until time t23 when it reaches the initial position via the return position at time t22. Then, from time t23, integration of the detection signal of the raindrop sensor is started, and the integrated value is The wiper operation starts again at time t24 when THO reaches the threshold value THO.

Note that in FIGS. 5 and 6, explanations are made assuming that the wiper blade moves at a constant speed and the amount of rain is constant.

Problems to be Solved by the Invention The timing at which the wiper operation should be started is when the number of raindrops adhering to the surface to be wiped reaches a certain amount and the forward visibility is obstructed.

Therefore, in the former conventional device, the raindrops detected during the period from time tit to time t12 are from time t12 to time t1.
Since the wiper operation for the period 3 has been wiped out, the accumulated value for that period is an unnecessary accumulated amount from time 0 tll to time t12 for the wiper operation from time t14.
Due to unnecessary integration during the period of
The time to reach HO becomes faster, and from the driver's perspective, it feels like the wiper operation starts earlier.

The latter conventional device solves the problem of the former in that the detection signal of the raindrop sensor is not integrated during the operating period from the wiper blade's initial position to the return position. Since the detection signals for the period from time t22 to time t23 until the wiper returns to the initial position are not integrated, from the driver's perspective, the start of the wiper operation seems to be delayed. That is, during the period from when the wiper blade returns to the initial position from the turning position, it is necessary to integrate detection signals for raindrops that have adhered to the wiper blade immediately after wiping.

Therefore, it is an object of the present invention to provide a wiper control device that more accurately estimates the amount of objects to be wiped, such as raindrops, so that the wiper operation can be started at a point desired by the driver. Our goal is to provide the following.

Means for Solving the Problems The present invention comprises: a raindrop sensor that detects rainfall conditions; a wiper blade that removes objects to be wiped attached to a surface to be wiped; and position detection means that detects a rest position of the wiper blade. , wiper driving means for reciprocating the wiper blade on the surface to be wiped; and responsive to the output of the position detection means, the wiper blade starts moving from a rest position on the surface to be wiped, and returns to the rest position again. In the period until reaching , the amount based on the output of the raindrop sensor is accumulated, and the first fl calculation value is accumulated, and the amount based on the output of the raindrop sensor is accumulated while the wiper blade is at rest at the rest position. and a wiper control means for performing a calculation from a 21st calculation value and outputting a drive signal for operating the wiper blade to the wiper drive means when the calculation result exceeds a predetermined threshold value. It is a control device.

Operation According to the wiper control device of the present invention, the raindrop sensor detects the rain state, and the wiper blade is controlled based on the output of the raindrop sensor. The wiper blade is driven by a wiper drive means, reciprocates over the surface to be wiped, and removes the object to be wiped attached to the surface to be wiped. The rest position of the wiper blade on the surface to be wiped is detected by a position detection means, and its output is given to the wiper control means. The wiper control means performs calculation based on the first integrated value and the second integrated value.

The first integrated value is a value obtained by integrating the amount based on the output of the raindrop sensor during a period from when the wiper blade starts moving from a rest position on the surface to be wiped until it reaches the rest position again. , the second'NI calculated value is when the wiper blade is at rest at the rest position,
This is a value obtained by integrating amounts based on the output of the raindrop sensor. When the calculation result of the first degree integrated value and the second M calculated 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 first integrated value and the second integrated value to be calculated are:
Since each wiper is calculated according to the amount of the object to be wiped off, the point at which the total integrated value that is the calculation result exceeds a predetermined threshold, that is, the point at which wiper operation starts, matches the driver's desired start point. can be done.

Embodiment As an embodiment of the present invention, a wiper control device for wiping away raindrops on 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 raindrops, which are objects to be wiped, attached to the windshield, which is the surface to be wiped, will be explained with reference to FIG.

FIG. 2 (1) shows the state immediately before the wiper operates, and the wiper blade 20 located at the initial position starts moving in the direction of the arrow Yl.The wiper blade 20 located at the initial position
Raindrops 21 are deposited on the windshield between the position and the turning position indicated by reference numeral 20a. Raindrops 21 are
Since these raindrops 21 are removed by the wiping motion of the wiper blade 20 in the direction of the arrow Yl, the integrated value of the detection signal from the raindrop sensor while these raindrops 21 are attached to the windshield is originally taken into consideration for the next wiper operation. should not do.

Next, in Fig. 2 (2), the wiper blade 22 is at the turning position 22.
The arrow Y2 indicates the direction of movement of the wiper blade 22.

In this state, the wiper blade 22 and the initial position 22
The raindrops 23 adhering to the wiper blade 2
2 is wiped away when returning to the initial position 22b, so the second
Similarly to the 1% case in 1), the accumulated value of the raindrop sensor during the period when the raindrops 23 are attached should not be taken into account for the next wiper operation.

By the way, the raindrops 24 that adhere after the wiper blade 22 removes the raindrops remain on the windshield until the next wiper operation starts.
It is necessary to integrate the detection signals from the raindrop sensor during the period in which the raindrop sensor 4 adheres.

In other words, since the period during which raindrops that affect the next wiper operation begins when the wiper blade passes the turning position, the amount based on the detection signal of the raindrop sensor is integrated immediately after the wiper blade passes the turning position. Although this makes it possible to accurately determine the amount of raindrops that have landed on the windshield, commonly used wiper motors and wiper control devices do not output signals to detect the turning position. In addition, raindrops
The area where raindrops are detected on the windshield and the area where raindrops actually adhere to the windshield are relatively apart, and the detection accuracy of the raindrop sensor varies. Taking the above reasons into consideration, the output from the raindrop sensor is calculated over a period as long as possible, and in the process of calculating the integrated value,
It is considered that the calculation of the amount of rainfall can be performed with higher accuracy by performing processing according to the raindrops to be considered shown in FIG. 2.

Therefore, this embodiment utilizes the fact that the presence of the wiper blade at 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, during the period from when the wiper blade starts moving from the rest position until it returns to the rest position again, the integrated value accumulated based on the output from the raindrop sensor has a value of 1.
It is multiplied by a coefficient of 7/4 and treated as an effective raindrop signal (first flf calculated value 11) for the next wiper operation. Thereafter, when the wiper blade is at rest in the rest position, the raindrop signal is ``The integrated value integrated based on the output from the raindrop is directly used as a valid raindrop signal (21st! Calculated value I2>
, and is added to the first integrated value (1) to calculate the integrated value (2) necessary for the next wiper operation. In this way, since the integrated value (2) is calculated taking into consideration the amount of raindrops while the wiper blade is in operation and while the wiper blade is stopped, the amount of raindrops deposited on the windshield can be accurately determined.

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 wiper operation is controlled based on the detection signal of the raindrop sensor 2. The wiper control circuit 1 functions as a raindrop sensor 2 that detects the amount of raindrops passing between the light receiving and emitting elements. A capacitive type that detects the amount of rain by detecting a change in capacitance due to attached raindrops, or a piezoelectric type that detects the amount of rain by detecting the energy of the raindrops colliding with a detection surface is used. The detection signal of the raindrop sensor 2 is sent to the waveform shaping circuit 3
After shaping the signal waveform and removing noise components, the signal is input to a processing circuit 4 implemented 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 a 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 within the wiper control circuit 1.

When the wiper switch 5 is set to the conductive state, automatic wiper control starts, 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. Wiper motor 10
A wiper arm (not shown) is connected to the rotating shaft of the wiper motor 10, and as the wiper motor 10 rotates, the wiper blade reciprocates on the windshield. A cam switch 12 is provided on the rotating shaft of the wiper motor 10, and as the rotating shaft of the wiper motor 10 rotates, the cam 13 also rotates. That is, the common contact Sa of the cam switch 12 is electrically connected to the individual contact sb when the wiper blade is in the rest position, while the contact 4b, which is not in the rest position when the wiper blade is in operation, is electrically connected to the individual contact sb. The common contact Sa is electrically connected to the individual contacts Sc. The individual contact sb is connected to ground potential, and the individual contact Sc is connected to the battery 8. Therefore, the cam switch 12 functions as a position detecting means, and by detecting the potential of the common contact Sa, it is determined whether the wiper blade is at the rest position. I can do two things.

Based on the detection signal from the raindrop sensor 2, the processing circuit 4
Switch the rotation speed of the wiper motor 10.

That is, when the wiper blade is operated intermittently or continuously at a low speed, a low-speed drive signal is output from the output terminal Pl of the processing circuit 4, and the drive circuit 11 operates the wiper motor 1.
Drive power is supplied to the low speed input terminal 13a of 0. W.I.
When the amount 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.

A terminal 13c of the wiper motor 10 is connected to the ground potential of the vehicle body, for example.

The control of the processing circuit 4 when the wiper blade operates at low speed will be briefly described below. First, processing circuit 4
When a low-speed drive signal is output from the output terminal Pl of the wiper motor 10, the wiper motor 10 starts rotating and the wiper blade starts a wiping operation. At this time, the cam switch 12 is switched from a conductive state between the common contact Sa and the individual contact sb to a conductive state between the common contact Sa and the individual contact Sc by the cam 13, and the potential of the common contact Sa becomes high level. after that,
When the cam switch 13 rotates further and the common contact Sa and the individual contact sb become conductive, the potential of the common contact Sa becomes low level, and the processing circuit 4 stops outputting from the output terminal Pl. As a result, the wiping operation of the wiper blade is stopped, and the wiper blade is stopped at the initial position, that is, the rest position.

The control according to the present invention in the wiper control device configured as described above will be explained based on the timing chart of FIG. 3.

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

At a time tl when the integrated value (2) based on the detection signal of the raindrop sensor 2 increases and reaches the threshold value TH, the processing circuit 4 sends a drive signal to the drive circuit 11, and the wiper starts operating.

At the same time, the processing circuit 4 clears the integrated value I of the detection signal from the raindrop sensor 2 and then starts integrating again. In this embodiment, during the period W2B from time tl to time t2 when the wiper blade passes through the return position and time t3 when the wiper blade returns to the initial position, which is the rest position, the detection signal of the raindrop sensor 2 is used as is. Instead of being integrated, a value obtained by multiplying the detection signal by a predetermined coefficient is integrated.

That is, as mentioned above, it is necessary to integrate only the raindrops that arrive at f times after the wiping operation of the wiper blade during the period W2B, and the amount of the raindrops that adhere is based on the detection signal of the raindrop sensor 2 that is integrated during the time W13. Since it is considered to be approximately equal to the total sum of 17'4, 1/4 is selected as the coefficient, and the value multiplied by the coefficient is measured as the first integrated value 1.

From the time t3 onwards, the wiper blade is at rest at the rest position during the intermittent time.

Therefore, from the time t3, the detection signal of the raindrop sensor 2 is directly integrated, a second integrated value I2 is measured, and the value added to the first integrated value 11 is the mg value I required for the next wiper operation. shall be treated as such.

That is, in FIG. 3, the period W starting from time t3
The value obtained by integrating the detection signals of the raindrop sensor 2 in B2 is the second integrated value I2, and this second integrated value ■2 is sequentially added to the first integrated value ■1 measured in the period W2B, The time WB2 continues until time t4 when the integrated value I of the sum exceeds the threshold value TH. Thereafter, at the time t4, the integrated value ■ is cleared in the same manner as at the time tl, and the subsequent wiper operation starts. In addition, in this embodiment, the explanation is given on the assumption 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 explained according to the flowchart shown in FIG. In the following f) explanation, the processing from time tl when the wiper starts the fe movement will be sequentially explained except for step m1.

In step m11, 5. Initialization processing such as clearing the memory area or resetting flags is performed. In step m2, it is determined whether the wiper is in operation. That is, the common contact Sa of the cam switch 12
is at a high level. At present, the wiper has just started operating, so the process advances from step m2 to step m3, and the timing counter C provided in advance is
The value of the timing counter C is updated by subtracting +1, and in step m4 it is determined whether the timing counter C is 10''. If the determination is negative, the process returns to step r
Returning to n2, the above-mentioned processing is repeated, and if the judgment is affirmative, the processing proceeds to step m5, a constant "4" is set to the timing counter C, and the processing proceeds to step rn
Proceed to step 6.

In step m6, the detection signals from the raindrop sensor 2 are integrated, and it is determined whether the integrated value I integrated in step m7 is equal to or greater than a predetermined value TH. If the integrated value ■ is less than the threshold TH, the process returns to step rn2 and steps rn2 to m7 are repeated.

During the course of the process, when the wiping operation of the wiper blade is completed, the determination in step m2 becomes negative, so the process continues from step m2 to step m.
The process proceeds to step m2.6 until the integrated value I exceeds the threshold TH. m6, and then repeat step rn7.

That is, the process does not proceed to step m6 until the constant ``4j'' set in the timing counter C in step m5 reaches r□ in step m4.
In other words, the process does not proceed to step m6 unless steps m2 to (n4) are repeated four times, so the detection signal from the raindrop sensor 2 is integrated while the wiper blade is performing the wiping motion. The timing corresponds to 1/4 of the timing for integrating the detection signals from the raindrop sensor 2 while the wiper blade is at rest. Therefore, the first integrated value 1 calculated by Wt through steps m2 to m7
1 is step m2. m6. The second value accumulated through m7
The result is similar to that obtained by multiplying the integrated value I2 by a constant of 1/4.

After that, in step m7, the integrated value ■ becomes 111M.
T) When the value becomes 1 or more, the process proceeds to step m8 to start the subsequent wiper operation, clear the integrated value in step m9, return to step m2 again, and repeat the above-mentioned operation.

Therefore, according to the above embodiment, the first product X value 11 is accumulated based on the output from the raindrop sensor during the wiping operation of the wiper blade, and According to the second integrated value (2) that is integrated based on the output, the integrated value necessary for the next wiper movement (F) is calculated, so the amount of raindrops that adhered to the windshield is calculated. This can be accurately defined, the wiper operation start point almost coincides with the driver's desired operation tlJr#4 start point, and wiper control with a good sense of operation can be realized.

Furthermore, in this embodiment, although the description is made in relation to a configuration in which the first integrated value 11 is multiplied by a coefficient of 17'4 compared to the second integrated value I2, for example, the predetermined threshold value is multiplied by 4 times. The first integrated value may be directly integrated, and the second integrated value may be multiplied by a constant of 4 to measure the second integrated value.

Effects of the Invention As described above, according to the present invention, the first integrated value measured while the wiper blade is in operation and the second integrated value measured while the wiper blade is at rest are attached to the surface to be wiped. Dispelled 1! By performing calculations differentiated according to the amount of J bodies, the I! of *i*: to be wiped attached to the surface to be wiped is Since the amount and the integrated value correspond to each other, the wiper operation start time coincides with the operation start time desired by the driver, and wiper control with a good sense of operation can be realized.

[Brief explanation of drawings]

Figure 1 shows an example of the wiper control device according to the present invention! A block diagram showing IN, FIG. 2 is a diagram for explaining the relationship between the wiper operation and the state of adhesion of raindrops, and FIG. 3 is a timing chart for explaining the wiper operation according to the present invention.
FIG. 4 is a flowchart for explaining the wiper operation according to the present invention, and FIG. 5 is a timing chart for explaining the operation f1 of a conventional wiper i control device that receives a detection signal from a raindrop sensor simultaneously with the start of the wiper operation. , FIG. 6 is a timing chart illustrating the operation of a conventional wiper control device that integrates detection signals from a raindrop sensor at the same time as the wiper operation ends. 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... Raindrops, TH... Threshold 2 Figure 3 Time 4 Figure 5 Figure 5

Claims (1)

[Scope of Claims] A raindrop sensor that detects a rainfall state; a wiper blade that removes an object to be wiped attached to a surface to be wiped; a position detection means that detects a rest position of the wiper blade; a wiper driving means for driving the wiper back and forth on the surface to be wiped; and a period from when the wiper blade starts moving from a rest position on the surface to be wiped until it reaches the rest position again in response to the output of the position detection means; , a first integrated value that is an integrated amount based on the output of the raindrop sensor, and a second integrated value that is an integrated amount that is based on the output of the raindrop sensor when the wiper blade is at rest in a rest position. A wiper control device comprising: a wiper control device that performs a calculation based on the calculation result and outputs a drive signal to the wiper drive device to operate the wiper blade when the calculation result exceeds a predetermined threshold.