JPH06489B2 - Wiper control device - Google Patents

Description

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

2. Description of the Related Art A so-called automatic wiper device, which controls a wiper operation based on a detection signal from a raindrop sensor, integrates 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. 6 is a time chart for explaining the operation of the conventional wiper device that integrates the detection signals from the raindrop sensor at the same time when the wiper operation starts. FIG. 6 (1) shows the temporal change of the integrated value of the detection signal, and FIG. 6 (2) shows the temporal change of the wiping position of the wiper blade.

At time t11, the integrated value is a predetermined threshold value TH
_When it reaches ₀ , the wiper operation starts, and the wiper housed in the initial position starts operating. At the same time when the wiper operation starts, the integrated value is once cleared, and then the detection signals from the raindrop sensor are integrated again. Then, when the wiper blade reaches the time t12, the wiper blade reaches the folding position, and when the time t13 is reached, the wiper blade returns to the initial position again. Even when the wiper blade returns to the initial position, the detection signals from the raindrop sensor continue to be integrated, the integrated value reaches the threshold value TH ₀ at time t14, and the wiper operation similar to the above is started again.

FIG. 7 is a time chart for explaining the operation of the conventional wiper device that integrates the detection signals from the raindrop sensor at the same time when the wiper operation is completed. Similar to the case of FIG. 6, FIG. 7 (1) shows the temporal change of the integrated value of the detection signal from the raindrop sensor, and FIG. 7 (2) shows the temporal change of the operating position of the wiper blade. The difference from the above-mentioned conventional example is that it starts from time t23 when the start of integration of the detection signal from the raindrop sensor is the time when the wiper operation ends, and time t21 when the integrated value reaches the threshold value TH _0. At the time t23, the wiper operation is started and the initial position is reached via the turnaround position at time t22 until the time t23 is reached.
Then, at time t23, the accumulation of the detection signal of the raindrop sensor is started, and the accumulated value reaches the threshold TH ₀ at time t2.
At 4, the wiper operation starts again.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The optimum timing for starting the operation of the wiper is when the amount of water droplets or the like adhering to the surface to be wiped reaches a certain amount and the front field of view is obstructed. Therefore, in the former conventional device, since the integrated value added in the period from time t11 to time t12 is wiped by the wiper operation in the period from time t11 to time t12, it is unnecessary for the wiper operation to operate from time t14. It is a total amount. Time t11
Due to unnecessary integration during the period from time t12 to time t12, the time required to reach the integrated value threshold TH ₀ is shortened, and the driver feels that the wiper operation has started earlier.

The latter conventional device solves the problem of the former in that the wiper blade does not integrate the detection signals of the raindrop sensor during the operation period from the initial position to the folding position like the former conventional device. From the time t22 until the blade returns to the initial position from the folding position to the time t2
Since the detection signals of the period 3 are not integrated, the driver feels that the start of the wiper operation is delayed. That is, in the period until the wiper blade returns from the folded position to the initial position, it is necessary to integrate the detection signals for the water droplets attached immediately after the wiper blade is wiped.

Therefore, an object of the present invention is to more accurately estimate the amount of an object to be wiped, such as water droplets to be wiped, so that the start time of the wiper operation matches the operation start time more desired by the driver. To provide.

Means for Solving the Problems The present invention detects that a raindrop sensor for detecting a rainfall state and a wiper blade for removing an object to be wiped adhering to a surface to be wiped have reached a folding position on the surface to be wiped. Position detecting means, wiper driving means for driving the wiper blade to reciprocate on the surface to be wiped, and in response to the output of the position detecting means, the wiper blade has reached the folding position on the surface to be wiped. And a wiper control means for outputting a drive signal for operating the wiper blade to the wiper drive means when the amount based on the output of the raindrop sensor is integrated and the integrated value exceeds a predetermined threshold value. The wiper control means also integrates only half of the amount based on the output of the raindrop sensor during the period until the wiper blade reaches the stop position from the folding position. A wiper control apparatus according to claim Rukoto.

The working raindrop sensor detects the rainfall condition, and the wiper control device controls the wiper blade based on the output value of the raindrop sensor. The wiper blade removes the object to be wiped adhering to the surface to be wiped, and the wiper blade is driven by the wiper driving means to reciprocate on the surface to be wiped. The fact that the wiper blade has reached the folding position on the surface to be wiped by the reciprocating drive is detected by the position detecting means, and its output is given to the wiper control means. The wiper control means starts integration of an amount based on the output of the raindrop sensor, for example, a pulse width of a pulse having a length corresponding to the raindrop diameter, from the time when the wiper blade reaches the folding position on the surface to be wiped. However, during the period until the wiper blade reaches the stop position from the folding position, only half of the amount based on the output of the raindrop sensor is integrated. That is,
After the end of the wiping operation, the amount based on the output from the raindrop sensor is integrated as it is, while the amount based on the output is corrected to ½ during the period from the turning position to the stop position and then integrated. To be done. Then, when the integrated value exceeds a predetermined threshold value, a drive signal is output to the wiper drive means to perform the wiper operation.

Therefore, the wiper blade is attached by the time it reaches the folding position from the stop position, without integrating the raindrops wiped when the wiper blade returns from the folding position to the stop position, and the wiper blade is By integrating only 1/2 of the amount based on the output of the raindrop sensor, the raindrops from the folding position to the returning position to the stop position do not integrate the raindrops wiped off at the time of the return operation.
In this way, unnecessary accumulation of raindrops can be prevented, and the wiper wiping interval can be matched with the interval at which the driver feels comfortable.

Embodiment As an embodiment of the present invention, a wiper control device for wiping off water droplets adhering to the windshield of an automobile will be described below. First, before describing the configuration of one embodiment of the present invention,
The relationship between the operating position of the wiper blade and the water droplets, which are the objects to be wiped on the windshield that is the surface to be wiped, will be described with reference to FIG. FIG. 2 (1) shows the state immediately after the wiper operation, in which the wiper blade 20 located at the initial position is shown.
Starts moving in the direction of arrow Y1. Water droplets 21 are attached on the windshield between the wiper blade 20 located at the initial position and the wiper blade 20a located at the folding position. Since the water droplets 21 are removed by the wiping operation of the wiper blade 20, the integrated value of the detection signal from the raindrop sensor while these water droplets 21 adhere to the windshield has no relation to the next wiper operation. Absent.

Next, in FIG. 2 (2), the wiper blade 22 is at the folding position 2.
The arrow Y2 indicates the moving direction of the wiper blade 22 while showing the way from 2a to the initial position 22b. In this state, the water droplets 23 adhering between the wiper blade 22 and the initial position 22b are not separated by the wiper blade 22 from the initial position 2
Since it is wiped off when returning to 2b, the integrated value of the raindrop sensor during the period in which the water droplet 23 adheres has no relation to the next wiper operation, as in the case of FIG. 2 (1).

However, since the water droplets 24 attached after the wiper blade 22 removes the water droplets are water droplets attached to the windshield until the next wiper operation starts, the water droplets 24
It is necessary to integrate the detection signals from the raindrop sensor during the period in which is attached.

That is, the period in which the water droplets that affect the next wiper operation is from when the wiper blade passes the folding position, and the amount based on the detection signal of the raindrop sensor should be integrated immediately after the wiper blade passes the folding position. Due to
The amount of water droplets attached 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 a raindrop sensor, an optical type that detects the amount of raindrops passing between the light emitting and receiving elements, a capacitance type that detects the amount of rain by detecting the volume change due to water droplets adhering to the detection surface, or the energy of water droplets that collide with the detection surface is detected. A piezoelectric type or the like that detects the amount of rainfall is used. The detection signal from the raindrop sensor 2 is shaped into a signal waveform by the waveform shaping circuit 3 and noise components are removed, and then input to a processing circuit 4 configured 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 A / D conversion circuit 7 converts the voltage value of the battery 8 into a digital amount and sends it to the processing circuit 4. 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.

The wiper switch 5 becomes conductive, the 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. A wiper arm (not shown) is connected to the rotation 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 the cam 13 also rotates when the rotation shaft of the wiper motor 10 rotates. The common contact Sa of the cam switch 12 is an individual contact Sb or an individual contact depending on the rotation position of the cam 13. It becomes conductive with any of Sc.

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 supplies the drive power to the low speed input terminal 13a of the wiper motor 10. . More rainfall,
When 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. Wiper motor 1
The 0 terminal 13c is connected to, 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. First, when a low speed drive signal is output from the output terminal P1 of the processing circuit 4, the wiper motor 1
0 starts rotating, and the wiper blade starts operating.
At this time, in the cam switch 12, the common contact Sa and the individual contact Sb are in a conductive state. Then, when the common contact Sa and the individual contact Sc are brought into conduction by the cam 13 that rotates in conjunction with the rotation shaft of the motor 10, it is detected that the potential of the common contact Sa becomes high level, and the processing circuit 4 is detected. The output of the low speed drive signal from the output terminal P1 is stopped. However, the wiper motor 10 is connected to the wiper motor 10 via the individual contact Sc, the common contact Sa, the power supply line pl1, and the drive circuit 11.
Power is continuously supplied to the low speed input terminal of. After that, when the cam switch 13 further rotates and the common contact Sa and the individual contact Sb become conductive, the operation of the wiper stops, and the wiper blade stops at the initial position, that is, the wiper storage position.

The control according to the present invention in the wiper control device configured as described above will be described based on the time chart of 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. 3 (2) shows a temporal change of the operating position of the wiper blade.

At time t1 when the integrated value 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 1 to operate.
The drive signal is sent to 1 and the operation of the wiper is started. Then, the processing circuit 4 does not integrate the detection signals from the raindrop sensor 2 during the period W12 from the initial position of the wiper blade to the folded position. Then, the integration is started from time t2 when the wiper blade reaches the folding position,
During the period of time W23 until the time t3 when reaching the initial position, the detection signal of the raindrop sensor 2 is not integrated as it is, but a value obtained by multiplying the detection signal by a predetermined coefficient is integrated. As this coefficient, it is considered that it is necessary to integrate the water droplets attached after the wiping operation of the wiper blade during the period of time W23, and the amount of the water droplets attached on the windshield is calculated by the detection signal of the raindrop sensor 2 during the period of time W23. Since it is considered to be approximately equal to 1/2 of the sum, 0.5 is selected as the count.

As a means for detecting that the wiper blade has reached the folding position, in the present embodiment, since the wiper reciprocating operation time can be almost estimated by the wiper drive voltage, the wiper blade is detected by detecting the wiper drive voltage. Is estimated to have reached the turnaround position. That is, the fourth
According to the graph showing the relationship between the wiper drive voltage and the wiper reciprocating operation time in the figure, the relationship between the wiper drive voltage supplied to the wiper motor 10 and the time during which the wiper blade reciprocates on the windshield is almost uniquely determined. Therefore,
The wiper drive voltage supplied to the wiper motor 10 is A / D
The conversion circuit 7 converts the digital value into a digital value, and the processing circuit 4 estimates the time t2 when the wiper blade reaches the folding position.

In the present embodiment, the folded position of the wiper blade is estimated by detecting the wiper drive voltage, but other means, for example, the operating position of the wiper arm may be directly detected by a potentiometer or the like.

Next, the processing executed in the processing circuit 4 will be described according to the flow cheat shown in FIG. In the following explanation,
Except for step s1, time t1 when the wiper starts operating
The processing from 1 to 3 will be sequentially described.

At step s1, initialization processing such as clearing the memory area or resetting the flag is performed. At step s2, it is determined whether or not the wiper is in operation. That is, when the drive signal is output from the processing circuit 4 to the drive circuit 11 or the common contact Sa of the cam switch 12 is at the high level, it is determined that the wiper is operating. At present, since the wiper has just started to operate, the process proceeds from step s2 to step s3,
The battery voltage supplied to the wiper motor 10 is read from the output of the A / D conversion circuit 7. In step s4, it is determined whether or not the wiper blade has reached the folding position. That is, the reciprocating operation time of the wiper is estimated from the battery voltage read in step s3, and it is determined whether the time from the start of the wiper has passed the time to reach the folded position of the wiper blade. If the time has not elapsed, the process proceeds from step s4 to step s2, and the above-mentioned processing is repeatedly executed until the wiper blade reaches the folding position.

When the wiper blade reaches the folding position, the process proceeds from step s4 to step s5, the detection signal from the raindrop sensor 2 is read, and the detection value is multiplied by a correction coefficient, for example, 0.5 to calculate the correction value. Step s6 is step s5
The correction value calculated in (1) is integrated into a predetermined memory area of the processing circuit 4. During a period of time W23 during which the wiper is in operation, steps s5 and s6 are executed, and the correction value obtained by multiplying the detection signal by the correction coefficient continues to be integrated.

When the time t3 at which the wiper operation ends is reached, step s
The process proceeds from step 2 to step s7, and the detection signal value from the raindrop sensor 2 is integrated as it is in the predetermined memory area.
Then, the process proceeds to step s8, the integrated value is compared with a predetermined threshold value TH, and if the integrated value does not reach the threshold value TH, the process proceeds from step s8 to step s2 to integrate the detection signal value from the raindrop sensor 2. Will continue.

When the integrated value reaches the threshold value TH, the process proceeds from step s8 to step 9, and a drive signal for operating the wiper is output to the drive circuit 11. In step s10,
The integrated value is cleared simultaneously with the output of the drive signal to the drive circuit 11.

As described above, according to the present invention, since the wiper blade starts the accumulation of the amount based on the output of the raindrop sensor from the time when the wiper blade reaches the folding position, the wiper blade adheres before reaching the folding position. After that, unnecessary raindrops that are wiped off before returning to the stop position are not accumulated. Further, since the wiper blade returns from the folding position to the stop position by half of the amount based on the output of the raindrop sensor, the increase amount of the integrated value in this period is equal to that after the return to the stop position. It will be half the increase of the integrated value in the normal period,
Unnecessary raindrops wiped before returning from the folding position to the stop position are not accumulated.

Therefore, the total amount of the objects to be wiped on the surface to be wiped and the integrated value almost correspond to each other, and the operation time of the wiper almost coincides with the operation start time desired by the driver, and the wiper with good feeling is obtained. Control is realized.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the 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 water droplet adhesion state, and FIG. 3 is related to the present invention. Timing chart for explaining wiper operation, fourth
FIG. 5 is a graph showing the relationship between the wiper drive voltage and the time required for the wiper to reciprocate, FIG. 5 is a flow chart for explaining the wiper operation according to the present invention, and FIG. 6 is a raindrop when the wiper operation starts. FIG. 7 is a time chart for explaining the operation of the conventional wiper device that integrates the detection signal from the sensor, and FIG. 7 is a time chart for explaining the operation of the conventional wiper device that integrates the detection signal from the raindrop sensor at the same time when the wiper operation is completed. Is. 1 ... Wiper control circuit, 2 ... Raindrop sensor, 8 ... Battery,
10 ... Wiper motor

Claims (1)

[Claims] 1. A raindrop sensor for detecting a rainfall condition, and position detecting means for detecting that a wiper blade for removing an object to be wiped adhering to the surface to be wiped has reached a folding position on the surface to be wiped. A wiper drive unit that drives the wiper blade to reciprocate and displace on the surface to be wiped, in response to the output of the position detection unit, the wiper blade of the raindrop sensor from when it reaches the folding position on the surface to be wiped. The amount based on the output is integrated, including a wiper control means for outputting a drive signal for operating the wiper blade to the wiper drive means when the integrated value exceeds a predetermined threshold value, the wiper control means, Further, in the period from the folded position to the stop position of the wiper blade, only half of the amount based on the output of the raindrop sensor is integrated. PA control device.