Wiper control device

Abstract

To provide a wiper controller which estimates a position of a wiper with a simple structure.SOLUTION: A determination part 64 of a wiper controller 30 acquires electric currents Im_Hi and IM_Lo flowing through a wiper motor 100 for driving a wiper which reciprocates between a lower inversion position and an upper inversion position. Further, the determination part 64 determines whether a wiper position is the lower inversion position or the upper inversion position based on a temporal change of the electric currents Im_Hi and IM_Lo flowing through the wiper motor 100.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a wiper control device. [Background technology]

[0002] As described in Patent Document 1, a wiper device is known that calculates the position of the wiper blade from a reference position based on the rotation speed of the wiper motor rotor detected by a Hall sensor and the reduction ratio of the wiper motor's reduction mechanism. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-43158 Summary of the Invention [Problem to be solved by the invention]

[0004] The wiper device described in Patent Document 1 is equipped with a Hall sensor that detects the rotation speed of the rotor. This requires wiring for signals from the Hall sensor, which complicates the configuration of the wiper device described in Patent Document 1. This increases the cost of the wiper device.

[0005] An object of the present disclosure is to provide a wiper control device that estimates the position of a wiper with a simple configuration. [Means for solving the problem]

[0006] The invention described in claim 1 includes an acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu), and a determination unit (S206, S208) that determines whether the position (Pw) of the wiper is the first position or the second position based on a change over time in the current flowing through the wiper motor, wherein the wiper motor has a characteristic that the current flowing through the wiper motor increases or decreases with a change over time when the wiper reciprocates between the first position and the second position. The determination unit determines whether the wiper is at the first position or the second position based on the time (Δt1) from when the wiper is at the first position to when the amount of change (ΔIm) in the current flowing through the wiper motor changes from a positive value to a negative value, and the time (Δt2) from when the wiper is at the second position to when the amount of change (ΔIm) in the current flowing through the wiper motor changes from a positive value to a negative value. This is a wiper control device. Furthermore, the invention described in claim 2 is a wiper control device that includes an acquisition unit (S200) that acquires a value related to a current flowing in a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu), and a determination unit (S206, S208) that determines whether the position (Pw) of the wiper is the first position or the second position based on a change over time in the current flowing in the wiper motor, wherein the wiper motor has a characteristic that the current flowing in the wiper motor increases or decreases with time as the wiper reciprocates between the first position and the second position, and the determination unit identifies whether the position of the wiper is the first position or the second position based on the initial position of the wiper and the number of times it has been determined that the position of the wiper is either the first position or the second position. The invention described in claim 3 is a wiper control device that includes an acquisition unit (S200) that acquires a value related to a current flowing in a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu), and a determination unit (S206, S208) that determines whether the wiper position (Pw) is the first position or the second position based on a change in the current flowing in the wiper motor over time, wherein the wiper motor has a characteristic in which the current flowing in the wiper motor increases or decreases over time as the wiper reciprocates between the first position and the second position, and the determination unit identifies whether the wiper position is the first position or the second position based on the time (Δt3) from when the wiper position becomes the first position to when it becomes the second position and the time (Δt4) from when the wiper position becomes the second position to when it becomes the first position. Furthermore, the invention described in claim 4 is a wiper control device that includes an acquisition unit (S200) that acquires a value related to a current flowing in a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu), and a determination unit (S206, S208) that determines whether the position (Pw) of the wiper is at either the first position or the second position based on a change over time in the current flowing in the wiper motor, wherein the wiper motor has a characteristic that the current flowing in the wiper motor increases or decreases with time as the wiper reciprocates between the first position and the second position, and the determination unit estimates the position of the wiper based on the time (Δt3) from when the wiper position becomes the first position to when it becomes the second position, the elapsed time since the wiper position becomes the first position, the time (Δt4) from when the wiper position becomes the second position to when it becomes the first position, and the elapsed time since the wiper position becomes the second position.

[0007] Also, claims 5 The invention described in is a wiper control device that includes an acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu), and a determination unit (S208, S222) that determines that the wiper position (Pw) is either the first position or the second position when the current flowing through the wiper motor is equal to or greater than a first threshold value and equal to or less than a second threshold value, and the determination unit changes the first threshold value and the second threshold value in accordance with a change in the voltage applied to the wiper motor. Furthermore, claims 6 The invention described in is a wiper control device that includes an acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu), and a determination unit (S208, S222) that determines that the wiper position (Pw) is either the first position or the second position when the current flowing through the wiper motor is equal to or greater than a first threshold value and equal to or less than a second threshold value, and the determination unit changes the first threshold value and the second threshold value in accordance with changes in the temperature of the wiper motor.

[0008] This allows the wiper position to be determined without the need for a Hall sensor to detect the rotor rotation speed, eliminating the need for wiring for the Hall sensor signal. Therefore, the wiper position can be estimated with a simple configuration.

[0009] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a configuration diagram of a wiper drive system in which a wiper control device according to a first embodiment is used. [Figure 2] FIG. 2 is a diagram showing a wiper of the wiper drive system. [Figure 3] 4 is a diagram showing the relationship between time and the current flowing through the wiper motor of the wiper drive system. [Figure 4] 4 is a flowchart showing the processing of a drive unit of the wiper control device. [Figure 5] 5 is a flowchart showing the processing of a determination unit of the wiper control device. [Figure 6] 4 is a graph showing the relationship between time and a smoothed value of a current flowing through a wiper motor of a wiper drive system. [Figure 7] 4 is a graph showing the relationship between time and a smoothed value of a current flowing through a wiper motor of a wiper drive system. [Figure 8] FIG. 3 is a configuration diagram of a wiper drive system in which a wiper control device according to a modified example of the first embodiment is used. [Figure 9] 6A and 6B are schematic views of a wiper for illustrating processing by a determination unit according to a modified example of the first embodiment. [Figure 10] FIG. 3 is a configuration diagram of a wiper drive system in which a wiper control device according to a modified example of the first embodiment is used. [Figure 11] FIG. 10 is a configuration diagram of a wiper drive system in which a wiper control device according to a second embodiment is used. [Figure 12] 5 is a flowchart showing the processing of a determination unit of the wiper control device. [Figure 13]4 is a graph showing the relationship between time and a smoothed value of a current flowing through a wiper motor of a wiper drive system. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described with reference to the drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals, and description thereof will be omitted.

[0012] (First embodiment) The wiper control device 30 of this embodiment is used in a vehicle wiper drive system 1. First, the wiper drive system 1 will be described.

[0013] As shown in FIG. 1, the wiper drive system 1 includes a motor unit 10, a motor ground 12, a motor power supply 14, a wiper switch 16, and a wiper control device 30.

[0014] The motor unit 10 has a wiper motor 100. The wiper motor 100 includes a Hi terminal 104, a Lo terminal 106, and a GND terminal 108. The Hi terminal 104 and the Lo terminal 106 are connected to a wiper control device 30, which will be described later. The GND terminal 108 is connected to a motor ground 12. The wiper motor 100 rotates at a relatively high speed when current is applied to the Hi terminal 104. The wiper motor 100 rotates at a slower speed when current is applied to the Lo terminal 106 than when current is applied to the Hi terminal 104. The rotation of the wiper motor 100 and a link mechanism (not shown) connected to the wiper motor 100 operate a wiper 90 of a vehicle, as shown in FIG. 2 .

[0015] As the wiper motor 100 rotates, the wiper 90 reciprocates between a lower reversal position Pd and an upper reversal position Pu on the windshield (not shown). As shown in FIG. 3, the wiper motor 100 has a characteristic in which the current flowing through the wiper motor 100 increases and decreases over time due to a link mechanism (not shown). The current value reaches a minimum at the lower reversal position Pd and the upper reversal position Pu. When the wiper switch 16 (described later) is turned off, the wiper motor 100 stops rotating so that the wiper 90 stops at the lower reversal position Pd.

[0016] 1, the motor power supply 14 is a secondary battery such as a lithium ion battery, a nickel-metal hydride battery, a lead storage battery, etc. The voltage of the motor power supply 14 is, for example, 12V.

[0017] The wiper switch 16 is operated by the operator and outputs a signal to the control unit 60 of the wiper control device 30 described below to set the operating state of the wiper 90 to one of the continuous high-speed mode, continuous low-speed mode, intermittent mode, or stop mode, as described below.

[0018] The wiper control device 30 controls the wiper motor 100 by controlling the voltage applied to the wiper motor 100. In this way, the wiper control device 30 controls the driving of the wiper 90 connected to the wiper motor 100. Specifically, the wiper control device 30 has a Hi switch 35, a Hi wiring 37, a Hi current detection unit 39, a Lo switch 45, a Lo wiring 47, a Lo current detection unit 49, and a control unit 60.

[0019] The Hi switch 35 includes a relay, a transistor, or the like. One end of the Hi switch 35 is connected to the motor power supply 14. The other end of the Hi switch 35 is connected to the Hi terminal 104 via the Hi wiring 37. The Hi switch 35 corresponds to a drive element, and is turned on and off by a signal from the control unit 60, which will be described later. This causes current to flow to or be cut off from the Hi terminal 104.

[0020] Hi current detection unit 39 includes a shunt resistor, a current mirror circuit, a Hall IC, or the like. Hi current detection unit 39 detects Hi current Im_Hi. Furthermore, Hi current detection unit 39 outputs a signal corresponding to the detected Hi current Im_Hi to control unit 60, which will be described later. Note that Hi current Im_Hi is a current that flows from motor power supply 14 to Hi terminal 104 via Hi switch 35 and Hi wiring 37.

[0021] The Lo switch 45 includes a relay, a transistor, or the like. One end of the Lo switch 45 is connected to the motor power supply 14. The other end of the Lo switch 45 is connected to the Lo terminal 106 via the Lo wiring 47. The Lo switch 45 corresponds to a drive element, and is turned on and off by a signal from the control unit 60, which will be described later. This causes the current to flow to or be cut off from the Lo terminal 106.

[0022] The Lo current detection unit 49 includes a shunt resistor, a current mirror circuit, a Hall IC, or the like. The Lo current detection unit 49 detects the Lo current Im_Lo. The Lo current detection unit 49 outputs a signal corresponding to the detected Lo current Im_Lo to the control unit 60, which will be described later. The Lo current Im_Lo is a current that flows from the motor power supply 14 to the Lo terminal 106 via the Lo switch 45 and the Lo wiring 47.

[0023] The control unit 60 is mainly composed of a microcomputer and includes a CPU, ROM, flash memory, RAM, I / O, a drive circuit, an A / D converter, and bus lines connecting these components. The control unit 60 is driven by voltage from the motor power supply 14 or a power supply (not shown). The control unit 60 also includes a drive unit 62 and a determination unit 64 as functional blocks.

[0024] The drive unit 62 executes a program stored in the control unit 60 to control the on / off of the Hi switch 35 and the Lo switch 45 based on signals from the wiper switch 16 and a determination unit 64 (described later). As a result, the drive unit 62 controls the voltage applied to the wiper motor 100. As a result, the operating state of the wiper 90 is set to one of a continuous high-speed mode, a continuous low-speed mode, an intermittent mode, and a stopped state.

[0025] The determination unit 64 executes a program stored in the control unit 60 to determine whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu based on signals from the Hi current detection unit 39 and the Lo current detection unit 49. The determination unit 64 also outputs a signal according to the determination result to the drive unit 62. The wiper position Pw is the position of the wiper 90.

[0026] The wiper drive system 1 is configured as described above. Next, control of the voltage applied to the wiper motor 100 by the drive unit 62 through program execution by the control unit 60 will be described with reference to the flowchart of Fig. 4. The program of the control unit 60 is executed, for example, when the ignition of the vehicle (not shown) is turned on.

[0027] In step S100, the drive unit 62 acquires various information. Specifically, the drive unit 62 acquires a signal from the wiper switch 16 to switch the operation state of the wiper 90 between the continuous high-speed mode, the continuous low-speed mode, the intermittent mode, and stop. The drive unit 62 also acquires a signal from the determination unit 64 indicating whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu.

[0028] Next, in step S102, the drive unit 62 determines whether the wiper switch 16 is on based on the signal from the wiper switch 16 acquired in step S100. When the drive unit 62 acquires a signal to change the operation state of the wiper 90 to the continuous high-speed mode, the continuous low-speed mode, or the intermittent mode in step S100, the drive unit 62 determines that the wiper switch 16 is on. Thereafter, the process of the drive unit 62 proceeds to step S104. When the drive unit 62 acquires a signal to stop the operation state of the wiper 90 in step S100, the drive unit 62 determines that the wiper switch 16 is off. At this time, the wiper 90 has stopped and there is no longer any need to drive the wiper 90, so the process of the drive unit 62 returns to step S100.

[0029] In step S104 following step S102, the drive unit 62 determines whether the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu based on the signal obtained from the determination unit 64 in step S100. If the wiper position Pw is not at the lower reversal position Pd or the upper reversal position Pu, the process by the drive unit 62 proceeds to step S106. If the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu, the process by the drive unit 62 proceeds to step S108.

[0030] In step S106 following step S104, the drive unit 62 turns on the Hi switch 35 or the Lo switch 45. This causes the wiper motor 100 to rotate, and the wiper 90 is driven.

[0031] Here, for example, assume that the wiper switch 16 is operated by an operator to output a signal to the drive unit 62 to change the operation state of the wiper 90 to the continuous high-speed mode. At this time, the drive unit 62 turns on the Hi switch 35. As a result, a voltage is applied to the wiper motor 100 from the motor power supply 14 via the Hi switch 35, the Hi wiring 37, and the Hi terminal 104. This causes the wiper motor 100 to rotate at a higher speed than when current is applied to the Lo terminal 106. Therefore, the wiper 90 connected to the wiper motor 100 rotates at a higher speed, and the operation state of the wiper 90 changes to the continuous high-speed mode. At this time, the Lo switch 45 is turned off.

[0032] Also, for example, suppose that the operator operates the wiper switch 16 to output a signal to the drive unit 62 to change the operation state of the wiper 90 to the continuous low speed mode. At this time, the drive unit 62 turns on the Lo switch 45. As a result, a voltage is applied to the wiper motor 100 from the motor power supply 14 via the Lo switch 45, the Lo wiring 47, and the Lo terminal 106. As a result, the wiper motor 100 rotates at a slower speed than when current is applied to the Hi terminal 104. Therefore, the wiper 90 connected to the wiper motor 100 rotates at a slower speed, and the operation state of the wiper 90 changes to the continuous low speed mode. Note that at this time, the Hi switch 35 is turned off. Furthermore, when the operation state of the wiper 90 is in the intermittent mode, the drive unit 62 turns on the Lo switch 45. As a result, the wiper motor 100 rotates at a slower speed. Furthermore, when the wiper 90 reciprocates between the lower reversal position Pd and the upper reversal position Pu and the wiper position Pw is at the lower reversal position Pd, the drive unit 62 turns off the Lo switch 45. This causes the wiper motor 100 to temporarily stop, and the wiper 90 also temporarily stops. Thereafter, the drive unit 62 turns on the Lo switch 45. This causes the wiper motor 100 to rotate at a low speed. Therefore, these operations cause the wiper 90 to intermittently reciprocate between the lower reversal position Pd and the upper reversal position Pu.

[0033] After the driving unit 62 controls the Hi switch 35 and the Lo switch 45 in this manner, the processing of the driving unit 62 returns to step S100.

[0034] In step S108 following step S104, the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu. Therefore, in step S108, the drive unit 62 performs PWM control on the wiper motor 100 by controlling the on / off of the Hi switch 35 or the Lo switch 45. As a result, the drive unit 62 reduces the power supplied to the wiper motor 100. This causes the wiper 90 to decelerate, thereby smoothly moving to the lower reversal position Pd or the upper reversal position Pu. Therefore, for example, the operating noise of the wiper 90 generated when the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu is reduced. Note that PWM stands for Pulse Width Modulation.

[0035] Specifically, when the wiper 90 is in the continuous high-speed mode, the drive unit 62 repeatedly turns on the Hi switch 35 for a first Hi time and then turns it off for a second Hi time. When the wiper 90 is in the continuous low-speed mode, the drive unit 62 repeatedly turns on the Lo switch 45 for a first Lo time and then turns it off for a second Lo time. These operations reduce the power supplied to the wiper motor 100, thereby decelerating the wiper 90. This allows the wiper 90 to move smoothly. When the wiper 90 is stopped, the wiper 90 smoothly stops at the lower reversal position Pd. The Hi first time, Hi second time, Lo first time, and Lo second time are set by experiment, simulation, or the like, so that the power supplied to the wiper motor 100 is reduced and the wiper 90 moves smoothly. In addition, by gradually changing the Hi first time, Hi second time, Lo first time, and Lo second time, the power supplied to the wiper motor 100 is changed, thereby making the operation of the wiper 90 smoother.

[0036] After the driving unit 62 has thus performed on / off control of either the Hi switch 35 or the Lo switch 45, the processing of the driving unit 62 returns to step S100.

[0037] As described above, the drive unit 62 controls the voltage applied to the wiper motor 100. Next, the determination of whether the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu by the determination unit 64 executed by the control unit 60 through program execution will be described with reference to the flowchart in Fig. 5. The period of a series of operations from when the determination unit 64 starts processing at step S200 until when the determination unit 64 returns to processing at step S200 is defined as the control cycle τ of the determination unit 64.

[0038] In step S200, the determination unit 64 acquires various information. Specifically, the determination unit 64 acquires a signal from the wiper switch 16 to change the operation state of the wiper 90 to the continuous high-speed mode, the continuous low-speed mode, the intermittent mode, or stop. The determination unit 64 also acquires the Hi current Im_Hi from the Hi current detection unit 39. The determination unit 64 also acquires the Lo current Im_Lo from the Lo current detection unit 49.

[0039] Next, in step S202, if the wiper 90 is in the continuous high-speed mode, the determination unit 64 calculates a smoothed value Im of the Hi current Im_Hi obtained in step S200 over time. As a result, the Hi current Im_Hi is smoothed over time, as shown in FIG. 6 . If the wiper 90 is in the continuous low-speed mode or the intermittent mode, the determination unit 64 calculates a smoothed value Im of the Lo current Im_Lo obtained in step S200 over time. As a result, the Lo current Im_Lo is smoothed over time. Note that smoothing here refers to creating an approximation function that extracts important features of data while eliminating noise, other fine structures, or sudden phenomena in statistics and signal processing. Smoothing can be performed using, for example, a simple moving average, a weighted moving average, an exponential moving average, a triangular moving average, a sine-weighted moving average, or a cumulative moving average. Furthermore, smoothing can also be performed using convolution, a KZ filter, an envelope, a moving standard deviation, or the like. Smoothing may also be performed using filters such as an averaging filter, a Gaussian filter, a median filter, a maximum filter, and a minimum filter.

[0040] When the change ΔIm in the smoothed value Im changes from a negative value to a positive value due to the characteristics of the link mechanism (not shown) and the wiper motor 100, the wiper position Pw becomes the lower reversal position Pd or the upper reversal position Pu.

[0041] 5, in step S204 following step S202, the determination unit 64 subtracts the smoothed value Im(n-1) in the control cycle τ(n-1) from the smoothed value Im(n) in the current control cycle τ(n). As a result, the determination unit 64 calculates the amount of change ΔIm(n) in the current control cycle τ(n). The amount of change ΔIm(0) is, for example, zero.

[0042] Next, in step S206, the determination unit 64 determines whether the change amount ΔIm(n-1) calculated in the previous control cycle τ(n-1) is less than zero and whether the change amount ΔIm(n) calculated in the current control cycle τ(n) is greater than zero. As a result, the determination unit 64 determines whether the change amount ΔIm has changed from a negative value to a positive value, thereby determining whether the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu.

[0043] Then, when the change amount ΔIm(n-1) calculated in the previous control cycle τ(n-1) is less than zero and the change amount ΔIm(n) calculated in the current control cycle τ(n) is greater than zero, the processing of the determination unit 64 proceeds to step S208. On the other hand, when the change amount ΔIm(n-1) calculated in the previous control cycle τ(n-1) is less than zero and the change amount ΔIm(n) calculated in the current control cycle τ(n) is equal to or less than zero, the processing of the determination unit 64 proceeds to step S212. Furthermore, when the change amount ΔIm(n-1) calculated in the previous control cycle τ(n-1) is equal to or greater than zero and the change amount ΔIm(n) calculated in the current control cycle τ(n) is greater than zero, the processing of the determination unit 64 proceeds to step S212. Furthermore, when the change amount ΔIm(n-1) calculated in the previous control cycle τ(n-1) is greater than or equal to zero and the change amount ΔIm(n) calculated in the current control cycle τ(n) is less than or equal to zero, the processing of the judgment unit 64 proceeds to step S212.

[0044] In step S208 following step S206, the change amount ΔIm changes from a negative value to a positive value. At this time, the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu. Therefore, at this time, the determination unit 64 determines that the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu. The determination unit 64 also outputs a signal indicating that the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu to the drive unit 62.

[0045] In step S210 following step S208, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu.

[0046] Here, the wiper 90 reciprocates between the lower reversal position Pd and the upper reversal position Pu. Therefore, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu based on the initial position of the wiper 90 and the number of times the wiper position Pw is determined to be the lower reversal position Pd or the upper reversal position Pu. For example, assume that the initial position of the wiper 90 is the lower reversal position Pd. At this time, when the wiper 90 is driven, the wiper position Pw becomes the upper reversal position Pu. This is the first time that the change amount ΔIm changes from a negative value to a positive value. Thereafter, the wiper position Pw returns from the upper reversal position Pu to the lower reversal position Pd. This is the second time that the change amount ΔIm changes from a negative value to a positive value. Therefore, the determination unit 64 counts the number of times that the wiper position Pw is determined to be the lower reversal position Pd or the upper reversal position Pu, and if the counted number is odd, the determination unit 64 determines that the wiper position Pw is the upper reversal position Pu. Furthermore, when the counted number is an even number, the determination unit 64 determines that the wiper position Pw is the lower reversal position Pd. Note that, although the initial position of the wiper 90 is the lower reversal position Pd here, this is not limitative. The initial position of the wiper 90 may also be the upper reversal position Pu. Furthermore, because the wiper 90 may stop between the lower reversal position Pd and the upper reversal position Pu due to a malfunction of the wiper 90 or the like, the initial position of the wiper 90 may also be a position between the lower reversal position Pd and the upper reversal position Pu.

[0047] 6, the change amount ΔIm may change from a positive value to a negative value due to the characteristics of the link mechanism (not shown) and the wiper motor 100. The time from when the wiper position Pw reaches the lower reversal position Pd until the change amount ΔIm changes from a positive value to a negative value is defined as a first time Δt1. The time from when the wiper position Pw reaches the upper reversal position Pu until the change amount ΔIm changes from a positive value to a negative value is defined as a second time Δt2. Depending on the characteristics of the link mechanism (not shown) and the wiper motor 100, the second time Δt2 may be shorter than the first time Δt1.

[0048] Therefore, the determination unit 64 may determine whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu based on the first time Δt1 and the second time Δt2. Specifically, the determination unit 64 measures the time from the last time the wiper position Pw was determined to be the lower reversal position Pd or the upper reversal position Pu to the time when the change amount ΔIm changes from a positive value to a negative value. If the measured time is the first time Δt1, the determination unit 64 determines that the wiper position Pw is the upper reversal position Pu. If the measured time is the second time Δt2, the determination unit 64 determines that the wiper position Pw is the lower reversal position Pd. Note that the determination unit 64 may determine that the wiper position Pw is the upper reversal position Pu when the measured time is equal to or greater than a threshold value. Alternatively, the determination unit 64 may determine that the wiper position Pw is the lower reversal position Pd when the measured time is less than the threshold value. Furthermore, the threshold value is set by experiment, simulation, or the like so as to be able to identify whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu.

[0049] 7, the time from when the wiper position Pw reaches the lower reversal position Pd to when it reaches the upper reversal position Pu is defined as a third time Δt3. Furthermore, the time from when the wiper position Pw reaches the upper reversal position Pu to when it reaches the lower reversal position Pd is defined as a fourth time Δt4. Depending on the characteristics of the link mechanism (not shown) and the wiper motor 100, the third time Δt3 may be longer than the fourth time Δt4.

[0050] Therefore, the determination unit 64 may determine whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu based on the third time Δt3 and the fourth time Δt4. Specifically, the determination unit 64 measures the time from when the wiper position Pw was previously determined to be the lower reversal position Pd or the upper reversal position Pu to when the wiper position Pw is currently determined to be the lower reversal position Pd or the upper reversal position Pu. If the measured time is the third time Δt3, the determination unit 64 determines that the wiper position Pw is the upper reversal position Pu. If the measured time is the fourth time Δt4, the determination unit 64 determines that the wiper position Pw is the lower reversal position Pd. If the measured time is equal to or greater than a threshold, the determination unit 64 may determine that the wiper position Pw is the upper reversal position Pu. If the measured time is less than the threshold, the determination unit 64 may determine that the wiper position Pw is the lower reversal position Pd. Furthermore, the threshold value is set by experiment, simulation, or the like so as to be able to identify whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu.

[0051] In this way, after determining whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu, the determination unit 64 outputs a signal according to the determined wiper position Pw to the drive unit 62. Thereafter, the processing of the determination unit 64 returns to step S200.

[0052] In step S212 following step S206, the change amount ΔIm does not change from a negative value to a positive value. At this time, the wiper position Pw is not at the lower reversal position Pd or the upper reversal position Pu. Therefore, at this time, the determination unit 64 determines that the wiper position Pw is not at the lower reversal position Pd or the upper reversal position Pu. The determination unit 64 also outputs a signal indicating that the wiper position Pw is not at the lower reversal position Pd or the upper reversal position Pu to the drive unit 62. Thereafter, the process of the determination unit 64 returns to step S200.

[0053] As described above, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu. Next, it will be described how the wiper control device 30 estimates the position of the wiper 90 with a simple configuration.

[0054] In step S200, the determination unit 64 functions as an acquisition unit that acquires a value related to the current flowing through the wiper motor 100 that drives the wiper 90 to reciprocate between the lower reversal position Pd and the upper reversal position Pu. The determination unit 64 also determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu based on the change over time in the current flowing through the wiper motor 100. For example, in steps S206 and S208, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu when the change in the current flowing through the wiper motor 100, ΔIm, changes from a negative value to a positive value. The lower reversal position Pd corresponds to the first position. The upper reversal position Pu corresponds to the second position.

[0055] This allows the wiper position Pw to be determined without providing a Hall sensor that detects the rotor rotation speed. This eliminates the need for wiring for a Hall sensor signal. Therefore, the wiper position Pw can be estimated with a simple configuration. Alternatively, the wiper position Pw may be estimated using a cam switch that turns on and off depending on the rotation of the wiper motor 100. In contrast, the wiper control device 30 of this embodiment estimates the wiper position Pw using the above configuration, so it does not need to include a cam switch.

[0056] Furthermore, the wiper control device 30 of the first embodiment also provides the following effects.

[0057] [1-1] In step S210, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu based on the first time Δt1 and the second time Δt2. Alternatively, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu based on the initial position of the wiper 90 and the number of times it has been determined that the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu. Alternatively, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu based on the third time Δt3 and the fourth time Δt4.

[0058] This makes it easier to identify whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu.

[0059] [1-2] The drive unit 62 reduces the power supplied to the wiper motor 100 when the wiper position Pw is either the lower reversal position Pd or the upper reversal position Pu.

[0060] This allows the wiper 90 to move smoothly to the lower reversing position Pd or the upper reversing position Pu, thereby reducing the operating noise of the wiper 90 that is generated when the wiper position Pw is the lower reversing position Pd or the upper reversing position Pu.

[0061] (Modification of the first embodiment) In the first embodiment, in step S108, the drive unit 62 performs on / off control of the Hi switch 35 or the Lo switch 45. As a result, the drive unit 62 reduces the power supplied to the wiper motor 100. Meanwhile, the means for reducing the power supplied to the wiper motor 100 by the drive unit 62 is not limited to the on / off control. For example, the drive unit 62 may reduce the power supplied to the wiper motor 100 by controlling a DC-DC converter (not shown) connected to the motor power supply 14 to lower the voltage applied to the wiper motor 100 from the motor power supply 14.

[0062] In the first embodiment, the Hi current detection unit 39 and the Lo current detection unit 49 are separate units, but this is not limiting. The Hi current detection unit 39 and the Lo current detection unit 49 may be integrated as a current detection unit 59, as shown in FIG. 8. In addition, the current detection unit 59 is disposed between the wiper motor 100 and the Hi switch 35 and the Lo switch 45, but this is not limiting. For example, the current detection unit 59 may be disposed between the motor power supply 14 and the Hi switch 35 and the Lo switch 45.

[0063] In the first embodiment, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu based on the third time Δt3 and the fourth time Δt4 in step S210. Alternatively, the determination unit 64 may estimate the wiper position Pw by calculating the wiper angle θw as shown in FIG. 9 based on the third time Δt3 and the fourth time Δt4. The wiper angle θw is the rotation angle of the wiper 90. The angle between the lower reversal position Pd and the upper reversal position Pu is defined as the maximum angle θmax. The maximum angle θmax is, for example, 140 degrees. Here, the value of the wiper angle θw is defined as being equal to or greater than zero and equal to or less than 2×θmax. The wiper position Pw is defined as being equal to the lower reversal position Pd when the wiper angle θw is zero or 2×θmax. The wiper position Pw is defined as being equal to the upper reversal position Pu when the wiper angle θw is θmax. Furthermore, when 0<θw<θmax, the wiper 90 rotates from the lower reversing position Pd to the upper reversing position Pu. When θmax<θw<2×θmax, the wiper 90 rotates from the upper reversing position Pu to the lower reversing position Pd.

[0064] Specifically, the determination unit 64, for example, divides the maximum angle θmax by the third time Δt3 to calculate the drive speed of the wiper 90 when the wiper position Pw changes from the lower reversal position Pd to the upper reversal position Pu. The determination unit 64 then multiplies the calculated drive speed of the wiper 90 by the elapsed time from the lower reversal position Pd to calculate the wiper angle θw. The determination unit 64 estimates the wiper position Pw by dividing the maximum angle θmax by the fourth time Δt4 to calculate the drive speed of the wiper 90 when the wiper position Pw changes from the upper reversal position Pu to the lower reversal position Pd. The determination unit 64 then multiplies the calculated drive speed of the wiper 90 by the elapsed time from the upper reversal position Pu to calculate the wiper angle θw. The determination unit 64 estimates the wiper position Pw by dividing the maximum angle θmax by the fourth time Δt4. The determination unit 64 then multiplies the calculated drive speed of the wiper 90 by the elapsed time from the upper reversal position Pu to calculate the wiper angle θw. The determination unit 64 estimates the wiper position Pw by dividing the maximum angle θmax by the fourth time Δt4.

[0065] Furthermore, from the above estimation, the determination unit 64 can determine whether the wiper position Pw is immediately before the lower reversal position Pd or the upper reversal position Pu. When the wiper position Pw is immediately before reaching the lower reversal position Pd or the upper reversal position Pu, the drive unit 62 performs PWM control on the wiper motor 100 by controlling the on / off of the Hi switch 35 or the Lo switch 45 in step S108. This allows the wiper 90 to be driven more smoothly. The wiper position Pw is immediately before the lower reversal position Pd when the wiper angle θw is equal to or greater than 2×θmax−Δ and less than 2×θmax. The wiper position Pw is immediately before the upper reversal position Pu when the wiper angle θw is equal to or greater than θmax−Δ and less than θmax. Δ is, for example, 1 to 10 degrees.

[0066] In the first embodiment, when the determination unit 64 determines in step S210 whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu, the determination unit 64 may output a signal corresponding to the determined wiper position Pw to an external device. For example, as shown in FIG. 10, the external device is a washer device 70. The washer device 70 controls the timing of spraying washer fluid to wash the windshield (not shown) based on the signal from the determination unit 64. For example, the washer device 70 sprays washer fluid when the determination unit 64 determines that the wiper position Pw is the lower reversal position Pd.

[0067] (Second embodiment) The second embodiment differs from the first embodiment in the configuration of the wiper control device 30. Also, the determination by the determination unit 64 as to whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu differs from the first embodiment. Other than these, the second embodiment is similar to the first embodiment.

[0068] Specifically, the wiper control device 30 further includes a voltage detection unit 50 and a temperature detection unit 55, as shown in FIG.

[0069] The voltage detection unit 50 includes a comparator circuit, a DC-DC converter, and the like, and detects the voltage applied to the wiper motor 100 from the motor power supply 14. The voltage detection unit 50 outputs a signal corresponding to the detected voltage to the determination unit 64. Note that, although the voltage detection unit 50 is connected between the motor power supply 14 and the Hi switch 35 and the Lo switch 45 in this example, the present invention is not limited to this. For example, the voltage detection unit 50 may be connected between the Hi switch 35 and the Hi terminal 104, and between the Lo switch 45 and the Lo terminal 106, respectively.

[0070] The temperature detection unit 55 has a thermistor or the like and detects the temperature of the wiper motor 100. Furthermore, the temperature detection unit 55 outputs to the determination unit 64 a signal corresponding to the detected temperature.

[0071] The wiper control device 30 of the second embodiment is configured as described above. Next, the determination of whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu by the determination unit 64 of the second embodiment will be described with reference to the flowchart of FIG.

[0072] In step S200, the determination unit 64 acquires various information. Specifically, similar to the first embodiment, the determination unit 64 acquires a signal from the wiper switch 16, the Hi current Im_Hi, and the Lo current Im_Lo. The determination unit 64 also acquires the voltage applied to the wiper motor 100 from the motor power supply 14 from the voltage detection unit 50. The determination unit 64 also acquires the temperature of the wiper motor 100 from the temperature detection unit 55.

[0073] Next, in step S202, if the operating state of the wiper 90 is the continuous high-speed mode, the determination unit 64 calculates a time-smoothed value Im of the Hi current Im_Hi acquired in step S200. On the other hand, if the operating state of the wiper 90 is the continuous low-speed mode or the intermittent mode, the determination unit 64 calculates a time-smoothed value Im of the Lo current Im_Lo acquired in step S200.

[0074] As described above, when the change amount ΔIm changes from a negative value to a positive value due to the characteristics of the link mechanism (not shown) and the wiper motor 100, the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu. At this time, as shown in Fig. 13, the smoothed value Im is equal to or greater than the first threshold value Im_th1 and equal to or less than the second threshold value Im_th2.

[0075] Furthermore, the smoothed value Im changes as the voltage applied from the motor power supply 14 to the wiper motor 100 changes. Furthermore, the smoothed value Im changes as the temperature of the wiper motor 100 changes. Therefore, it is preferable to change the first threshold value Im_th1 and the second threshold value Im_th2 depending on the voltage applied from the motor power supply 14 to the wiper motor 100 and the temperature of the wiper motor 100.

[0076] 12, in step S220 following step S202, the determination unit 64 calculates a first threshold value Im_th1 and a second threshold value Im_th2. Specifically, the determination unit 64 calculates the first threshold value Im_th1 and the second threshold value Im_th2 by using the voltage applied to the wiper motor 100 from the motor power supply 14 and the temperature of the wiper motor 100 obtained in step S200, and a map. Note that the map is set, for example, so that the first threshold value Im_th1 and the second threshold value Im_th2 increase as the voltage applied to the wiper motor 100 from the motor power supply 14 increases. Also, the map is set, for example, so that the first threshold value Im_th1 and the second threshold value Im_th2 increase as the temperature of the wiper motor 100 decreases. Furthermore, the map is set by experiment, simulation, or the like so that it is possible to determine whether a wiper position Pw, which will be described later, is the lower reversal position Pd or the upper reversal position Pu.

[0077] Subsequently, in step S222, the determination unit 64 determines whether the smoothed value Im calculated in step S202 is equal to or greater than the first threshold value Im_th1 and equal to or less than the second threshold value Im_th2 calculated in step S220. As a result, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu.

[0078] When the smoothed value Im is equal to or greater than the first threshold value Im_th1 and equal to or less than the second threshold value Im_th2, the process of the determination unit 64 proceeds to step S208. When the smoothed value Im is less than the first threshold value Im_th1 or greater than the second threshold value Im_th2, the process of the determination unit 64 proceeds to step S212.

[0079] In step S208 following step S222, the smoothed value Im is equal to or greater than the first threshold value Im_th1 and equal to or less than the second threshold value Im_th2, so the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu. Therefore, at this time, the determination unit 64 determines that the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu. The determination unit 64 also outputs a signal indicating that the wiper position Pw is at the lower reversal position Pd or the upper reversal position Pu to the drive unit 62.

[0080] In step S210 following step S208, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu, as in the first embodiment. Therefore, details of this determination will be omitted. After determining whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu, the determination unit 64 outputs a signal corresponding to the determined wiper position Pw to the drive unit 62. Thereafter, the process of the determination unit 64 returns to step S200.

[0081] In step S212 following step S206, the smoothed value Im is less than the first threshold value Im_th1 or greater than the second threshold value Im_th2, so the wiper position Pw is not the lower reversal position Pd or the upper reversal position Pu. Therefore, at this time, the determination unit 64 determines that the wiper position Pw is not the lower reversal position Pd or the upper reversal position Pu. The determination unit 64 also outputs a signal indicating that the wiper position Pw is not the lower reversal position Pd or the upper reversal position Pu to the drive unit 62. Thereafter, the process of the determination unit 64 returns to step S200.

[0082] As described above, the determination unit 64 determines whether the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu. The second embodiment also provides the same advantages as the first embodiment. The second embodiment also provides the following advantages.

[0083] [2] Here, the Hi current Im_Hi, the Lo current Im_Lo, and the smoothed value Im change as the voltage applied to the wiper motor 100 changes. In addition, the Hi current Im_Hi, the Lo current Im_Lo, and the smoothed value Im change as the temperature of the wiper motor 100 changes.

[0084] In response to this, in step S220, the determination unit 64 changes the first threshold value Im_th1 and the second threshold value Im_th2 in accordance with a change in the voltage applied to the wiper motor 100. Furthermore, in step S220, the determination unit 64 changes the first threshold value Im_th1 and the second threshold value Im_th2 in accordance with a change in the temperature of the wiper motor 100.

[0085] This prevents the determination unit 64 from making an erroneous determination that the smoothed value Im falls outside the range between the first threshold value Im_th1 and the second threshold value Im_th2 even when the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu.

[0086] (Modification of the second embodiment) In the second embodiment, similarly to the first embodiment, the first time Δt1 is the time from when the wiper position Pw reaches the lower reversal position Pd until the change amount ΔIm changes from a positive value to a negative value, and the second time Δt2 is the time from when the wiper position Pw reaches the upper reversal position Pu until the change amount ΔIm changes from a positive value to a negative value.

[0087] Alternatively, the first time Δt1 may be the time from when the wiper position Pw reaches the lower reversal position Pd until the smoothed value Im becomes equal to or greater than the third threshold. The second time Δt2 may be the time from when the wiper position Pw reaches the upper reversal position Pu until the smoothed value Im becomes equal to or greater than the third threshold. In this manner, the first time Δt1 and the second time Δt2 may be set without using the change amount ΔIm. The third threshold is set to be greater than the second threshold Im_th2 and equal to or less than the maximum value of the Hi current Im_Hi or the Lo current Im_Lo.

[0088] (Other embodiments) The present disclosure is not limited to the above-described embodiments, and appropriate modifications can be made to the above-described embodiments. Furthermore, it goes without saying that the elements constituting the embodiments in the above-described embodiments are not necessarily essential unless they are specifically stated as essential or are considered to be clearly essential in principle.

[0089] The acquisition unit, determination unit, driver, and method described herein may be implemented by a special-purpose computer configured with a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the acquisition unit, determination unit, driver, and method described herein may be implemented by a special-purpose computer configured with a processor configured with one or more dedicated hardware logic circuits. Alternatively, the acquisition unit, determination unit, driver, and method described herein may be implemented by one or more special-purpose computers configured with a processor and memory programmed to perform one or more functions in combination with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

[0090] The above embodiments may be combined as appropriate.

[0091] (Aspects of the present disclosure) [Point 1] an acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu); a determination unit (S206, S208) that determines whether the wiper position (Pw) is the first position or the second position based on a time change in the current flowing through the wiper motor; A wiper control device comprising: [Point 2] The wiper control device described in Aspect 1, wherein the determination unit determines that the position (Pw) of the wiper is either the first position or the second position when the change in current (ΔIm) flowing through the wiper motor changes from a negative value to a positive value. [Point 3] The wiper control device according to aspect 1 or 2, wherein the determination unit determines whether the position of the wiper is the first position or the second position based on the time (Δt1) from when the position of the wiper reaches the first position to when the amount of change (ΔIm) in the current flowing through the wiper motor changes from a positive value to a negative value, and the time (Δt2) from when the position of the wiper reaches the second position to when the amount of change (ΔIm) in the current flowing through the wiper motor changes from a positive value to a negative value. [Point 4] The wiper control device according to aspect 1 or 2, wherein the determination unit determines whether the position of the wiper is the first position or the second position based on the initial position of the wiper and the number of times it has determined that the position of the wiper is either the first position or the second position. [Point 5] The wiper control device according to aspect 1 or 2, wherein the determination unit determines whether the position of the wiper is the first position or the second position based on the time (Δt3) from when the position of the wiper becomes the first position to when it becomes the second position and the time (Δt4) from when the position of the wiper becomes the second position to when it becomes the first position. [Point 6] The wiper control device according to any one of Aspects 1 to 5, wherein the determination unit estimates the position of the wiper based on a time (Δt3) from when the position of the wiper becomes the first position to when it becomes the second position, an elapsed time since the position of the wiper becomes the first position, a time (Δt4) from when the position of the wiper becomes the second position to when it becomes the first position, and an elapsed time since the position of the wiper becomes the second position. [Point 7] an acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu); a determination unit (S208, S222) that determines that the position (Pw) of the wiper is either the first position or the second position when the current flowing through the wiper motor is equal to or greater than a first threshold and equal to or less than a second threshold; A wiper control device comprising: [Point 8] Aspect 8. The wiper control device according to Aspect 7, wherein the determination unit changes the first threshold value and the second threshold value in accordance with a change in the voltage applied to the wiper motor. [Point 9] Aspect 9. The wiper control device according to aspect 7 or 8, wherein the determination unit changes the first threshold value and the second threshold value in accordance with a change in the temperature of the wiper motor. [Point 10] The wiper control device according to any one of aspects 1 to 9, further comprising a drive unit (62) that reduces the power supplied to the wiper motor when the wiper is in either the first position or the second position. [Point 11] The wiper control device further includes a drive element (35, 45) that, when turned on, applies a voltage to the wiper motor to rotate the wiper motor, The wiper control device described in aspect 10, wherein the drive unit reduces the power supplied to the wiper motor by turning the drive element on and off when the wiper is in either the first position or the second position. [Explanation of symbols]

[0092] 14 Motor power supply 16 Wiper switch 35 Hi switch 39 Hi current detection section 45 Lo switch 49 Lo current detection section 60 Control Unit 62 Drive unit 64 Judgment section 100 wiper motor

Claims

1. An acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu); a determination unit (S206, S208) that determines whether the wiper position (Pw) is the first position or the second position based on a time change in current flowing through the wiper motor; Equipped with the wiper motor has a characteristic that a current flowing through the wiper motor increases and decreases with time when the wiper reciprocates between the first position and the second position, The determination unit determines whether the wiper is in the first position or the second position based on the time (Δt1) from when the wiper is in the first position to when the change in the current (ΔIm) flowing through the wiper motor changes from a positive value to a negative value, and the time (Δt2) from when the wiper is in the second position to when the change in the current (ΔIm) flowing through the wiper motor changes from a positive value to a negative value.

2. An acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu); a determination unit (S206, S208) that determines whether the wiper position (Pw) is the first position or the second position based on a time change in current flowing through the wiper motor; Equipped with the wiper motor has a characteristic that a current flowing through the wiper motor increases and decreases with time when the wiper reciprocates between the first position and the second position, The determination unit determines whether the position of the wiper is the first position or the second position based on the initial position of the wiper and the number of times it has determined that the position of the wiper is either the first position or the second position.

3. An acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu); a determination unit (S206, S208) that determines whether the wiper position (Pw) is the first position or the second position based on a time change in current flowing through the wiper motor; Equipped with the wiper motor has a characteristic that a current flowing through the wiper motor increases and decreases with time when the wiper reciprocates between the first position and the second position, The determination unit determines whether the wiper is in the first position or the second position based on the time (Δt3) from when the wiper is in the first position to when it becomes the second position, and the time (Δt4) from when the wiper is in the second position to when it becomes the first position.

4. An acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu); a determination unit (S206, S208) that determines whether the wiper position (Pw) is the first position or the second position based on a time change in current flowing through the wiper motor; Equipped with the wiper motor has a characteristic that a current flowing through the wiper motor increases and decreases with time when the wiper reciprocates between the first position and the second position, The determination unit is a wiper control device that estimates the position of the wiper based on the time (Δt3) from when the wiper position becomes the first position to when it becomes the second position, the elapsed time since the wiper position becomes the first position, the time (Δt4) from when the wiper position becomes the second position to when it becomes the first position, and the elapsed time since the wiper position becomes the second position.

5. an acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu); a determination unit (S208, S222) that determines that the position (Pw) of the wiper is either the first position or the second position when the current flowing through the wiper motor is equal to or greater than a first threshold and equal to or less than a second threshold; Equipped with The determination unit changes the first threshold value and the second threshold value in accordance with a change in the voltage applied to the wiper motor.

6. an acquisition unit (S200) that acquires a value related to a current flowing through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu); a determination unit (S208, S222) that determines that the position (Pw) of the wiper is either the first position or the second position when the current flowing through the wiper motor is equal to or greater than a first threshold and equal to or less than a second threshold; Equipped with The determination unit changes the first threshold value and the second threshold value in accordance with a change in the temperature of the wiper motor.

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