JPH02164650A - Wiper controller - Google Patents

Abstract

PURPOSE:To secure a wiper operation that agrees with the feeling of an operator, by adding a quanty that is based on the output of a raindrop sensor, from a time when a wiper blade has reached a return position, and arranging so that a wiping action may be conducted when its addition value has surpassed a predetermined threshold value. CONSTITUTION:The output of a raindrop sensor 2 consisting of a pair of light receiving/emitting elements is inputted into a wave form arrangement circuit 3, and here, a level discrimination is made at a discrimination level previously determined, and the detection signal of an L level is arranged to be given to a processing circuit 4 only during a term t in which the sensor output is more than a discrimination level. At the processing circuit 4, the addition of the term t in which the detection signal is led out, is made, and a wiper drive signal is made to output at a timepoint when its addition value has surpassed a predetermined threshold value. In this instance, the addition of a detection signal from the raindrop sensor 2 is made to commence from a time when a wiper blade has reached a return position, at the processing circuit 4. As a result, the quantity of waterdrops attached to a front glass is accurately surmised, and a wiper operation with a good feeling is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION 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 rain conditions.

Conventional technology A so-called automatic wiper device that controls wiper operation based on a detection signal from a raindrop sensor outputs a detection signal from the raindrop sensor, and starts wiper operation when the ffX value exceeds a predetermined value. .

As a means of integrating the detection signals from this raindrop sensor,
Conventionally, when the wiper blade starts operating, or when the
There is a device that counts up from the end.

FIG. 6 is a time chart illustrating the operation of a conventional wiper device that outputs a detection signal from a raindrop sensor at the same time as the wiper operation starts. FIG. 6(1) shows the temporal change in the integrated value of the detection signal, and FIG. 6(2) shows the temporal change in the wiping position of the wiper blade.

At time tll, the integrated value reaches a predetermined threshold T
When Ho is reached, the wiper operation starts, and the wiper housed in the initial position starts operating.

At the same time as the wiper operation starts, the integrated value is once cleared, and then the detection signal from the raindrop sensor is integrated again. Then, when the wiper blade reaches time t12, it reaches the turning position, and when time t13 comes, it 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, and at time t14, the integrated value reaches the threshold T Ho, and the wiper operation starts again in the same manner as described above.

FIG. 7 is a time chart illustrating the operation of a conventional wiper device that integrates detection signals from a raindrop sensor at the same time as the wiper operation ends. FIG. 7 (1) shows the temporal change in the integrated value of the detection signal from the raindrop sensor as in the case of FIG. 6, and FIG. 7 (2) shows the temporal change in the operating position of the wiper blade. The difference from the conventional example described above is that the integration of the detection signal from the raindrop sensor starts from time t23, which is the time when the wiper operation ends, and the integration value reaches the threshold value TH. The wiper operation starts at t21, and 'V1n is not performed until time t23 when it reaches the initial position via the return position at time t22.Then, from time t2B, the integration of the detection signal of the raindrop sensor is started, and the integrated value is The wiper operation starts again at time 24 when the threshold value TH0 is reached.

Problems to be Solved by the Invention The optimal timing to start the wiper operation is when a certain amount of water droplets or the like adhering to the surface to be wiped reaches a certain level and obstructs the forward visibility.

Therefore, in the former conventional device, the integrated value added over a period of 12 from time tll is from time t11 to time t.
It is wiped away by the wiper operation for a period of 12, so at time t
Unnecessary mii for wiper operation activated from lJ
It is. Due to unnecessary integration during the period from time tll to time t12, the time it takes for the integrated value to reach the threshold value T Ho becomes faster, and the driver feels that the wiper operation starts earlier.

The following conventional device solves the problem of the former in that it does not integrate the detection signal of the raindrop sensor during the operating period from the initial position to the return position of the wiper blade. , time α1 from time t22 until the wiper blade returns from the folded position to the initial position
Since the detection signal between wi at t23 is not integrated, the driver feels that the start of wiper operation is delayed. In other words, during the period from when the wiper blade returns to the initial position from the folded position, the wiper blade directly wipes (=
This is because it is necessary to calculate rIt of the detection signal for the water droplet that has landed on the water droplet.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a wiper control device that more accurately estimates the amount of objects to be wiped such as water droplets to be wiped, so that the wiper operation start point more closely matches the operation start point desired by the driver. Our goal is to provide the following.

Means for Solving the Problems The present invention provides a raindrop sensor for detecting rainfall conditions, a wiper blade for removing objects to be wiped attached to a surface to be wiped, and a position detection means for detecting the operating position of the wiper blade. , wiper driving means for reciprocating the wiper blade on the surface to be wiped; and i7 in response to the output of the position detection means from the time when the wiper blade reaches the turning position on the surface to be wiped.
wiper control means that calculates the amount based on the output of the droplet sensor, and outputs a drive signal to the wiper drive means to cause the wiper blade to operate when the integrated value exceeds a predetermined threshold; This is a unique wiper control device.

Operation The raindrop sensor detects rain conditions, and the wiper control device controls the wiper blade based on the output value of this raindrop sensor. The wiper blade removes objects to be wiped that are attached to the surface to be wiped, and the wiper blade is driven by a wiper driving means to reciprocate on the surface to be wiped. The operating position of the wiper blade on the surface to be wiped is detected by the position detection means, and its output is given to the wiper control means. The wiper control means integrates the amount based on the output of the raindrop sensor from the time when the wiper blade reaches the turning position on the surface to be wiped. When the integrated value exceeds a predetermined threshold value, a drive signal is output to the wiper drive means to cause the wiper operation to be performed.

Embodiment As an embodiment of the present invention, a wiper control device for wiping away water droplets 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 water droplets, which are the object to be wiped, adhering to the windshield, which is the surface to be wiped, will be explained with reference to FIG. FIG. 2 (1) shows the state immediately after the wiper operation, with the wiper blade 20 located at the initial position.
starts moving in the direction of arrow Y1. Water droplets 21 are attached to the windshield between the wiper blade 20 located at the initial position and the wiper blade 20a located at the folded 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 are attached to the windshield has no relation to the next wiper operation. do not have.

Next, in FIG. 2 (2), the wiper blade 22 is at the folding position 2.
2a to the initial position 22b, and arrow Y2 indicates the moving direction of the wiper blade 22. In this state, the water droplet 23 that has settled one inch between the wiper blade 22 and the initial position 22b is wiped away when the wiper blade 22 returns to the initial position 22b, so it is different from the case in FIG. 2 (1). Similarly, the accumulated value of the raindrop sensor during the period when the waterdrops 23 adhere has no relation to the next wiper operation.

However, the water droplets 24 that adhere after the wiper blade 22 removes the water droplets 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 raindrops 4 are attached.

In other words, the period during which water droplets that affect the next wiper operation begins to adhere is from when the wiper blade passes the turning position, and the scenery based on the detection signal of the raindrop sensor is integrated immediately after the wiper blade passes the turning position. According to
It is possible to accurately define the amount of water droplets deposited on the windshield.

Next, a configuration of an embodiment of a 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 wiper operation is controlled based on a detection signal from the raindrop sensor 2.

The previous generation raindrop sensor detects the amount of raindrops passing between the light receiving and emitting elements, the capacitive type detects the amount of rain by detecting the change in capacitance due to water droplets adhering to the detection surface, or the capacitive type detects the amount of rain by detecting the energy of the water droplets colliding with the detection surface. A piezoelectric type is used to detect the The detection signal from the raindrop sensor 2 is subjected to signal waveform shaping and removal of noise components by a waveform shaping circuit 3, and then inputted to a processing circuit 4 constituted by a microcomputer or the like. The wiper switch 5 is a switch for instructing the processing circuit 4 to perform automatic wiper control, and the switch signal is input to the processing circuit 4 via a 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 representation 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 within the wiper control circuit 1.

The wiper switch 5 becomes conductive and 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 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. When the rotating shaft of the wiper motor 10 rotates, the cam 13 also rotates, and the common contact Sa of the cam switch 12 is set to the individual contact sb or the individual contact sb depending on the rotational position of the cam 13. Individual contact Sc
It becomes conductive with one of the two.

Based on the detection signal from the raindrop sensor 2, the processing circuit 4
The rotation speed of the wiper motor 10 can be turned off.

That is, when the wiper blade is operated intermittently or continuously at low speed, a low-speed drive signal is output from the output terminal 21 of the processing circuit 4, and the drive circuit 11 supplies drive power to the low-speed input terminal 13a of the wiper motor 10. supply.

When the amount of rain 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, for example, a vehicle body.

A brief explanation will be given of the control of the processing circuit 4 when the wiper blade moves at low speed. 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 operating.At this time, the cam switch 12 has the common contact Sa and the individual contact sb in a state of conduction.Then, the cam 13, which rotates in conjunction with the rotating shaft of the motor 10, connects the common contact Sa and the open side. When the contact Sc becomes conductive, the processing circuit 1 detects that the potential of the common contact Sa becomes high level and stops outputting the low-speed drive signal from the output terminal P1. Individual contact Sc, common contact Sa,
Power continues to be supplied to the low-speed input terminal of the wiper motor 10 via the power supply line p (1, drive circuit 11).After that, the cam switch 13 rotates further and the common contact Sa and the individual contacts εb become electrically connected. The wiper operation is stopped and the wiper blade is stopped at the initial position, that is, the wiper storage position.

The control according to the present invention in the wiper control device configured as above will be explained based on the 317I time chart.

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

Based on the detection signal of the raindrop sensor 2 <r? The calculated value increases,
At time t1 when the threshold value TH is reached, the processing circuit 4 sends a drive signal to the drive circuit 11, and the wiper starts operating.

The processing circuit 4 does not integrate the detection signals from the raindrop sensor 2 during the time period W12 from the initial position to the turning position of the wiper blade. Then, integration is started from time t2 when the wiper blade reaches the turning position, but during a period of time W23 until time t3 when the wiper blade reaches the initial position, the detection signal of the raindrop sensor 2 is not integrated as is, but the detection signal A value obtained by multiplying by a predetermined coefficient is integrated. As this coefficient, it is considered necessary to integrate the water droplets that adhered after the wiping operation of the wiper blade during the period of time W23, and the amount of water droplets that adhere to the windshield is determined by the detection signal of the raindrop sensor 2 during the period of time W2B. Since it is considered to be approximately equal to 1/2 of the total sum, 0.5 is selected as the count.

As a means for detecting that the wiper blade has reached the folded position, in this embodiment, since the reciprocating time of the wiper can be estimated based on the wiper drive voltage, by detecting the wiper drive voltage, the wiper blade is folded back. It is estimated that the position is f'l 32. That is, according to the graph showing the relationship between the wiper drive voltage and the wiper forward movement time of 1 s and tf in FIG. 4, the wiper motor 1
The relationship between the wiper drive voltage supplied to the windshield and the time during which the wiper blade moves back and forth on the windshield is almost uniquely determined. Therefore, the wiper drive voltage supplied to the wiper motor 10 is converted into a digital value by the A/D conversion circuit 7, and the processing circuit 4 estimates the time L2 when the wiper blade reaches the turning position.

In the present embodiment, the turning position of the wiper blade is estimated by detecting the wiper drive voltage, but other means, such as a potentiometer or the like, may be used to directly detect the operating position of the wiper arm.

Next, the processing executed in the processing circuit 4 will be explained according to the flow chart shown in FIG. In the following explanation,
Time t1 when the wiper starts operating except for step s1
The processing from here on will be explained in order.

In step S1, an initialization process such as clearing the memory area or setting flags 1 to 1 is performed.

In step $2, it is determined whether the wiper is in operation. That is, it is determined that a drive signal is detected from the processing circuit 4 to the drive circuit 11, or that the F, A+ wipers whose common contact Sa of the cam switch 12 is at a high level are in operation. Currently, the wiper has just started operating, so from step 52 to step 53.
Then, the battery voltage supplied to the wiper motor 10 is read from the output of the A/D conversion circuit 7. Step S4
It is determined whether the wiper blade has reached the turning position. That is, the reciprocating operation time of the wiper is estimated from the battery voltage read in step $3, and it is determined whether the time from when the wiper was activated has elapsed for the wiper blade to reach the folded position. If the wiper blade has not passed, the process advances from step S4 to step S2, and the above-described process is repeatedly executed until the wiper blade reaches the turning position.

When the wiper blade reaches the turning position, the process proceeds from step s4 to step S5, where the detection signal from the raindrop sensor 2 is read, and the detected value is multiplied by a correction coefficient, for example 0.5, to calculate a correction value.

In step S6, the correction value calculated in step S5 is accumulated in a predetermined memory area of the processing circuit 4. During the period of time W23 during which the wiper is operating, 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 wiper operation ends at time 3, step S6 is executed.
2, the process proceeds to step S7, where the detected signal value from the raindrop sensor 2 is directly accumulated in the predetermined memory area.

Then, the process advances to step S8, and the fI calculated value is compared with a predetermined threshold value TH, and if the cumulative value has not reached the threshold value TH, the process advances from step S8 to step S2, where the detection signal from the raindrop sensor 2 is detected. Accumulation of values continues.

When the integrated value reaches the threshold value TH, the process advances from step S8 to step S9, and a drive signal for operating the wiper is output to the drive circuit 11.

In step slo, the integrated value is cleared at the same time as the drive signal is output to the drive circuit 11.

Effects of the Invention As described above, according to the present invention, while the wiper is operating, a part of the detection signal of the raindrop sensor is not integrated, so that the total amount of the tired wiping object that has landed on the surface to be wiped can be calculated. The integrated values almost correspond to each other, and the wiper activation time almost matches the activation start time desired by the driver, achieving wiper control with good feeling.

[Brief explanation of the drawing]

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 wiper operation and water droplet adhesion, and FIG. 3 is a block diagram showing an embodiment of the wiper control device according to the present invention. 4 is a graph showing the relationship between the wiper drive voltage and the time required for the wiper to reciprocate, and FIG. 5 is a timing chart for explaining the wiper operation according to the present invention. Fig. 6 is a time chart explaining the operation of the conventional wiper device that integrates the detection signal from the raindrop sensor at the same time as the wiper operation starts, and Fig. 7 shows the detection signal from the raindrop sensor at the same time as the wiper operation ends. 2 is a time chart illustrating the operation of a conventional wiper device that integrates signals. 1... Wiper control circuit, 2 - Raindrop sensor, 8... Battery, 10... Wiper motor agent Patent attorney Number of strokes Keiichi Fig. 2b Fig. M Fig. Fig. 6 Fig.

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 an operating position of the wiper blade; wiper driving means for driving the wiper back and forth on the surface to be wiped; and a wiper drive means responsive to the output of the position detection means to detect an amount based on the output of the raindrop sensor from the time when the wiper blade reaches a turning position on the surface to be wiped. A wiper control device comprising: a wiper control means for integrating and outputting a drive signal for operating the wiper blade to the wiper drive means when the integrated value exceeds a predetermined threshold value.