Wiper control device

Abstract

An estimation unit (64) of a wiper control device (30) acquires a value relating to a current (ImHith, ImLoth) flowing to a wiper motor (100) that drives a wiper that reciprocates between a lower flip position and an upper flip position. Furthermore, the estimation unit (64) estimates a wiper angle, which is a wiper rotation angle, on the basis of a current ripple having a periodicity in accordance with the driving of the wiper motor (100) among the current flowing to the wiper motor (100). Furthermore, if the position of the wiper is imminent to the lower flip position or the position of the wiper is imminent to the upper flip position, a drive unit (62) of the wiper control device (30) reduces the power supplied to the wiper motor (100).

Description

Technical Field

[0001] The invention relates to a wiper control device. Background Art

[0002] Conventionally, as described in Patent Document 1, there is known a wiper device that calculates the position of a wiper blade from a reference position based on the rotor speed of a wiper motor detected by a Hall sensor and the reduction ratio of a reduction mechanism of the wiper motor.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-43158 Summary of the invention

[0006] The wiper device described in Patent Document 1 is provided with a Hall sensor for detecting the rotor speed. As a result, since signal wiring for the Hall sensor is required, the structure of the wiper device described in Patent Document 1 becomes complicated. Therefore, the cost of the wiper device increases. In addition, the wiper blade sometimes moves excessively because it does not stop at the lower flip position or the upper flip position, that is, sometimes overrun occurs, and it is also required to suppress the overrun.

[0007] An object of the present disclosure is to provide a wiper control device that estimates a rotation angle of a wiper with a simple structure and suppresses overrunning of the wiper.

[0008] The wiper control device involved in the first embodiment of the present invention comprises: an acquisition unit, which acquires a value related to the current flowing to the wiper motor, and the wiper motor drives the wiper to move back and forth between a first position and a second position; an estimation unit, which estimates the wiper angle as the wiper rotation angle based on a current ripple, and the current ripple is a current ripple in the current flowing to the wiper motor that has a periodicity corresponding to the drive of the wiper motor; and a driving unit, which reduces the power supplied to the wiper motor in any of the cases where the position of the wiper is about to change to the first position and the position of the wiper is about to change to the second position.

[0009] In addition, the wiper control device involved in the second mode of the present disclosure includes: an acquisition unit, which acquires a value related to the current flowing to the wiper motor, and the wiper motor drives the wiper to travel back and forth between a first position and a second position; and an estimation unit, which estimates a wiper angle as a wiper rotation angle based on a current ripple, wherein the current ripple is a current ripple in the current flowing to the wiper motor and has a periodicity corresponding to the drive of the wiper motor. The wiper motor has: a first terminal, the first terminal is supplied with power so that the wiper motor rotates at a first speed; and a second terminal, the second terminal is supplied with power so that the wiper motor rotates at a second speed lower than the first speed. The wiper control device also includes: a first element, which, by being turned on, causes current to flow to the wiper motor via the first terminal, thereby rotating the wiper motor; and a second element The invention relates to a device for rotating the wiper motor by controlling the on / off switching of the first and second elements. The device comprises a control unit for controlling the on / off switching of the first and second elements. When the first element is on, if the position of the wiper is about to change to the first position or the position of the wiper is about to change to the second position, the control unit switches the first element from on to off to stop the power supply to the first terminal, and switches the second element from off to on to supply power to the second terminal. If the position of the wiper changes from being about to change to the first position to the first position or the position of the wiper changes from being about to change to the second position to the second position, the control unit switches the first element from off to on to supply power to the first terminal, and switches the second element from being on to off to stop the power supply to the second terminal.

[0010] In addition, the wiper control device involved in the third embodiment of the present disclosure includes: an acquisition unit, which acquires a value related to the current flowing to the wiper motor, and the wiper motor drives the wiper to travel back and forth between a first position and a second position; and an estimation unit, which estimates the wiper angle as the wiper rotation angle based on the current ripple, and the current ripple is a current ripple in the current flowing to the wiper motor that has a periodicity corresponding to the drive of the wiper motor. The wiper motor has: a first terminal, the first terminal is supplied with power so that the wiper motor rotates at a first speed; and a second terminal, the second terminal is supplied with power so that the wiper motor rotates at a second speed lower than the first speed. The wiper control device also includes: a first element, the first element is turned on to allow current to flow to the wiper via the first terminal motor, thereby rotating the wiper motor; a second element, which, by being turned on, allows current to flow to the wiper motor via the second terminal, thereby rotating the wiper motor; and a driving unit, which controls the connection and disconnection of the first element and the second element. When the first element is turned on, if the position of the wiper is about to change to the first position or the position of the wiper is about to change to the second position, the driving unit stops the power supply to the first terminal by turning the first element from being turned on, and keeps the second element disconnected. If the position of the wiper changes from being about to change to the first position to the first position or the position of the wiper changes from being about to change to the second position to the second position, the driving unit supplies power to the first terminal by turning the first element from being turned off, and keeps the second element disconnected.

[0011] Thus, the wiper angle can be estimated without providing a Hall sensor for detecting the rotor speed. Therefore, it is not necessary to provide signal wiring for the Hall sensor. Therefore, the wiper angle can be estimated with a simple structure. In addition, the wiper moves smoothly to the first position or the second position by decelerating when it is about to change to the first position or the second position. Therefore, it is possible to prevent the wiper from moving excessively without stopping at the first position or the second position, that is, it is possible to prevent the wiper from over-limiting. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a block diagram of a wiper drive system used in a wiper control device according to an embodiment.

[0013] Figure 2 is a diagram showing a wiper of a wiper drive system.

[0014] Figure 3 is a graph of the current flowing to the wiper motor of the wiper drive system versus time.

[0015] Figure 4 This is a diagram for explaining switching of the current detection range of the wiper control device.

[0016] Figure 5 : is a flowchart showing the processing of the driving unit of the wiper control device.

[0017] Figure 6 1 is a flowchart showing the processing of the estimation unit of the wiper control device.

[0018] Figure 7 This is a diagram for explaining the calculation of the number of pulses by the estimation unit.

[0019] Figure 8 This is a configuration diagram of a wiper drive system used in a wiper control device according to Modification 1 of an embodiment.

[0020] Fig. 9 This is a diagram for explaining calculation of the number of pulses by an estimation unit in a wiper control device according to Modification 1 of one embodiment.

[0021] Fig.10 This is a diagram for explaining the relationship between the wiper angle and the on / off states of the Hi switch and the Lo switch in the processing of the drive unit in the wiper control device according to the second modification of the embodiment.

[0022] Fig.11 This is a diagram for explaining the relationship between the wiper angle and the on / off states of the Hi switch and the Lo switch in the processing of the drive unit in the wiper control device according to the second modification of the embodiment. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments will be described with reference to the drawings.

[0024] It should be noted that, in the following embodiments, the same or equivalent parts are denoted by the same reference numerals, and description thereof will be omitted.

[0025] In the wiper control device of this embodiment, the rotation angle of the wiper can be estimated with a simple structure. For example, the wiper control device is used in a wiper drive system of a vehicle. First, the wiper drive system is described.

[0026] like Figure 1 As shown, 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 .

[0027] 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 described later. The GND terminal 108 is connected to the motor ground 12. By supplying power to the Hi terminal 104, the wiper motor 100 rotates at a higher speed. In addition, by supplying power to the Lo terminal 106, the wiper motor 100 rotates at a lower speed than when power is supplied to the Hi terminal 104. Furthermore, by the rotation of the wiper motor 100 and a link mechanism (not shown) connected to the wiper motor 100, the wiper 90 of the vehicle is rotated as shown in FIG. Figure 2 Perform the actions shown.

[0028] In addition, the wiper 90 reciprocates between the lower flip position Pd and the upper flip position Pu on the windshield glass (not shown) by the rotation of the wiper motor 100. At this time, the wiper motor 100 repeatedly makes the plurality of commutator segments in the commutator of the wiper motor 100 and the brushes contact and non-contact. Figure 3 As shown, the wiper motor 100 has a characteristic of generating a current ripple Ir, which is a current ripple Ir that changes with a periodicity corresponding to the driving of the wiper motor 100 in the current flowing to the wiper motor 100. The amplitude of the current ripple Ir is set to 1 to 2 A, for example. In addition, when the wiper switch 16 described later is turned off, the rotation of the wiper motor 100 stops, so that the wiper 90 stops at the lower flip position Pd.

[0029] In addition, here, Figure 2 As shown, the rotation angle of the wiper 90 when moving back and forth between the lower flip position Pd and the upper flip position Pu is set to the wiper angle θw. In addition, the angle between the lower flip position Pd and the upper flip position Pu is set to the maximum angle θmax. The maximum angle θmax is, for example, 140 degrees. In addition, the value of the wiper angle θw is set to a range greater than zero and less than 2×θmax. In addition, the case where the wiper angle θw is zero or 2×θmax is set to the case where the wiper position Pw is the lower flip position Pd. In addition, the case where the wiper angle θw is θmax is set to the case where the wiper position Pw is the upper flip position Pu. In addition, the case where 0<θw<θmax is set to the case where the wiper 90 rotates from the lower flip position Pd toward the upper flip position Pu. In addition, the case where θmax<θw<2×θmax is set to the case where the wiper 90 rotates from the upper flip position Pu toward the lower flip position Pd.

[0030] return Figure 1 The motor power source 14 is a secondary battery such as a lithium ion battery, a nickel-metal hydride battery, or a lead storage battery. The voltage of the motor power source 14 is, for example, 12V.

[0031] Wiper switch 16 is operated by an operator to output a signal to control unit 60 of wiper control device 30 described later, which causes wiper 90 to operate in any of a continuous high speed mode, a continuous low speed mode, an intermittent mode, and a stop mode described later.

[0032] The wiper control device 30 controls the wiper motor 100 by controlling the voltage applied to the wiper motor 100. Thus, the wiper control device 30 controls the driving of the wiper 90 connected to the wiper motor 100. Specifically, the wiper control device 30 includes a Hi switch 35, a Hi wiring 37, a Hi current detection unit 39, a Hi switching unit 41, a Lo switch 45, a Lo wiring 47, a Lo current detection unit 49, a Lo switching unit 51, and a control unit 60.

[0033] The Hi switch 35 includes a relay or a transistor. In addition, one end of the Hi switch 35 is connected to the motor power supply 14. In addition, the other end of the Hi switch 35 is connected to the Hi terminal 104 through the Hi wiring 37. In addition, the Hi switch 35 is equivalent to a driving element, and is turned on and off according to a signal from the control unit 60 described later. As a result, the power supply or current to the Hi terminal 104 is cut off.

[0034] The Hi current detection unit 39 includes a shunt resistor, a current mirror circuit, or a Hall IC. In addition, the Hi current detection unit 39 detects the Hi current Im_Hi. In addition, the Hi current detection unit 39 outputs a signal corresponding to the detected Hi current Im_Hi to the control unit 60 described later via the Hi switching unit 41 described later. It should be noted that the Hi current Im_Hi is a current flowing from the motor power supply 14 to the Hi terminal 104 via the Hi switch 35 and the Hi wiring 37.

[0035] The Hi switching unit 41 switches the Hi current detection range. For example, the Hi switching unit 41 includes a switching element such as a transistor. In addition, the Hi switching unit 41 switches the resistance of the Hi current detection unit 39 by turning the switching element on and off. As a result, the Hi switching unit 41 switches the Hi current detection range to either the Hi first detection range or the Hi second detection range. It should be noted that the Hi current detection range is the detection range of the current detected by the Hi current detection unit 39. Figure 4 As shown, the Hi first detection range is, for example, 0 to 50 A. The Hi second detection range is a detection range smaller than the Hi first detection range, for example, 0 to 5 A. Figure 4In the figure, the first detection range for Hi is represented by Rd1. In addition, the second detection range for Hi is represented by Rd2. In addition, since the second detection range for Hi is smaller than the first detection range for Hi, the resolution of the current detected in the second detection range for Hi is higher than the resolution of the current detected in the first detection range for Hi.

[0036] In addition, here, the Hi switching unit 41 switches the Hi current detection range to either the Hi first detection range or the Hi second detection range based on the Hi current Im_Hi. Specifically, when the Hi current Im_Hi is greater than the Hi protection threshold Im_Hi_th, the Hi switching unit 41 sets the Hi current detection range to the Hi first detection range. Thus, the Hi current detection unit 39 can detect a relatively large Hi current Im_Hi. Therefore, it is possible to detect abnormal heating of the Hi wiring 37, the wiper motor 100, and the wiper 90 caused by the relatively large Hi current Im_Hi.

[0037] In addition, when the Hi current Im_Hi is less than the Hi protection threshold Im_Hi_th, the Hi switching unit 41 sets the Hi current detection range to the Hi second detection range. Thus, when the Hi current Im_Hi is less than the Hi protection threshold Im_Hi_th, the Hi current detection unit 39 can detect the Hi current Im_Hi with high accuracy. Therefore, it is easy to detect the current ripple Ir contained in the Hi current Im_Hi. It should be noted that the Hi protection threshold Im_Hi_th is set through experiments or simulations to take into account the protection of the Hi wiring 37, the wiper motor 100, and the wiper 90, and the current detection accuracy.

[0038] return Figure 1 , the Lo switch 45 includes a relay or a transistor. In addition, one end of the Lo switch 45 is connected to the motor power supply 14. In addition, the other end of the Lo switch 45 is connected to the Lo terminal 106 through the Lo wiring 47. In addition, the Lo switch 45 is equivalent to a driving element, and is turned on and off according to a signal from the control unit 60 described later. Thus, the current is energized or cut off to the Lo terminal 106.

[0039] The Lo current detection unit 49 includes a shunt resistor, a current mirror circuit, or a Hall IC. In addition, the Lo current detection unit 49 detects the Lo current Im_Lo. In addition, the Lo current detection unit 49 outputs a signal corresponding to the detected Lo current Im_Lo to the control unit 60 described later via the Lo switching unit 51 described later. It should be noted that the Lo current Im_Lo is a current flowing from the motor power supply 14 to the Lo terminal 106 via the Lo switch 45 and the Lo wiring 47.

[0040] The Lo switching unit 51 switches the Lo current detection range. For example, the Lo switching unit 51 includes a switching element such as a transistor. In addition, the Lo switching unit 51 switches the resistance of the Lo current detection unit 49 and the like by turning the switching element on and off. Thus, the Lo switching unit 51 switches the Lo current detection range to any one of the first detection range for Lo and the second detection range for Lo. It should be noted that the Lo current detection range is the detection range of the current detected by the Lo current detection unit 49. The first detection range for Lo is, for example, 0 to 50A. The second detection range for Lo is a detection range smaller than the first detection range for Lo, for example, 0 to 5A. In addition, since the second detection range for Lo is smaller than the first detection range for Lo, the resolution of the current detected in the second detection range for Lo is higher than the resolution of the current detected in the first detection range for Lo.

[0041] In addition, here, the Lo switching unit 51 switches the Lo current detection range to either the first detection range for Lo or the second detection range for Lo based on the Lo current Im_Lo. Specifically, when the Lo current Im_Lo is greater than the Lo protection threshold Im_Lo_th, the Lo switching unit 51 sets the Lo current detection range to the first detection range for Lo. Thus, the Lo current detection unit 49 can detect a relatively large Lo current Im_Lo. Therefore, it is possible to detect abnormal heating of the Lo wiring 47, the wiper motor 100, and the wiper 90 caused by the relatively large Lo current Im_Lo.

[0042] In addition, when the Lo current Im_Lo is less than the Lo protection threshold Im_Lo_th, the Lo switching unit 51 sets the Lo current detection range to the Lo second detection range. Thus, when the Lo current Im_Lo is less than the Lo protection threshold Im_Lo_th, the Lo current detection unit 49 can detect the Lo current Im_Lo with high accuracy. Therefore, it is easy to detect the current ripple Ir included in the Lo current Im_Lo. It should be noted that the Lo protection threshold Im_Lo_th is set by experiments or simulations to take into account the protection of the Lo wiring 47, the wiper motor 100, and the wiper 90, and the current detection accuracy.

[0043] The control unit 60 is mainly composed of a microcomputer, etc., and includes a CPU, ROM, flash memory, RAM, I / O, a drive circuit, an A / D converter, a comparator circuit, a DCDC converter, a low-pass filter, and a bus connecting these structures. In addition, the control unit 60 is driven by a voltage from the motor power supply 14 or a power supply not shown. In addition, the control unit 60 has a motor temperature estimation unit 61, a drive unit 62, and an estimation unit 64 as functional blocks.

[0044] The motor temperature estimation unit 61 estimates the temperature of the wiper motor 100 by executing a program built into the control unit 60. For example, the motor temperature estimation unit 61 obtains the Hi current Im_Hi from the Hi current detection unit 39 through the Hi switching unit 41. In addition, the motor temperature estimation unit 61 obtains the Lo current Im_Lo from the Lo current detection unit 49 through the Lo switching unit 51. In addition, the motor temperature estimation unit 61 obtains the ambient temperature Te by communicating with a detection device not shown in the figure. In addition, the motor temperature estimation unit 61 obtains the motor voltage Vm through wiring not shown in the figure. It should be noted that in the detection device not shown in the figure, the ambient temperature Te is detected by using a device such as a thermistor, for example. The motor voltage Vm is the voltage of the wiper motor 100.

[0045] In addition, the motor temperature estimation unit 61 calculates the power of the wiper motor 100 based on the acquired Hi current Im_Hi or Lo current Im_Lo and the motor voltage Vm. In addition, the motor temperature estimation unit 61 estimates the temperature of the wiper motor 100 using the calculated power, the acquired ambient temperature Te, and the map. In addition, the motor temperature estimation unit 61 outputs a signal corresponding to the estimated wiper motor 100 to the estimation unit 64 described later. It should be noted that when the ambient temperature Te is constant, the heat generated by the wiper motor 100 increases as the power increases. Therefore, the map for estimating the temperature of the wiper motor 100 is set, for example, so that the temperature of the wiper motor 100 increases as the power increases. In addition, when the power of the wiper motor 100 is constant, the ambient temperature Te and the temperature of the wiper motor 100 are balanced. Therefore, the map for estimating the temperature of the wiper motor 100 is set, for example, so that the temperature of the wiper motor 100 increases as the ambient temperature Te increases.

[0046] The driving unit 62 controls the on / off of the Hi switch 35 and the Lo switch 45 based on the signals from the wiper switch 16 and the estimation unit 64 described later by executing the program built in the control unit 60. Thus, the driving unit 62 controls the voltage applied to the wiper motor 100. Therefore, the operation state of the wiper 90 becomes any one of the continuous high speed mode, the continuous low speed mode, the intermittent mode and the stop.

[0047] The estimation unit 64 estimates the wiper angle θw based on the signal from the wiper switch 16, the temperature of the wiper motor 100, the Hi current Im_Hi, and the Lo current Im_Lo by executing a program built into the control unit 60. The estimation unit 64 outputs a signal corresponding to the estimated wiper angle θw to the drive unit 62.

[0048] The wiper drive system 1 is configured as described above. Figure 5 : The control unit 60 executes a program, and the driving unit 62 controls the voltage applied to the wiper motor 100. It should be noted that the program of the control unit 60 is executed when the ignition or power of the vehicle (not shown) is turned on, for example.

[0049] In step S100 , the drive unit 62 acquires various information. Specifically, the drive unit 62 acquires a signal from the wiper switch 16 that changes the operating state of the wiper 90 to the continuous high speed mode, the continuous low speed mode, and the intermittent mode. In addition, the drive unit 62 acquires the wiper angle θw from the estimation unit 64 .

[0050] Next, in step S102, the drive unit 62 determines whether the wiper switch 16 is turned on based on the signal from the wiper switch 16 obtained in step S100. And, when a signal that changes the operation state of the wiper 90 to the continuous high-speed mode, the continuous low-speed mode, or the intermittent mode is obtained in step S100, the drive unit 62 determines that the wiper switch 16 is turned on. Then, the processing of the drive unit 62 is transferred to step S104. In addition, when a signal that stops the operation state of the wiper 90 is obtained in step S100, the drive unit 62 determines that the wiper switch 16 is turned off. At this time, since the wiper 90 is stopped, there is no need to drive the wiper 90, so the processing of the drive unit 62 returns to step S100.

[0051] In step S104 following step S102, the drive unit 62 determines whether the wiper angle θw obtained in step S100 is greater than θmax-Δ and less than θmax. Thus, the drive unit 62 determines whether the wiper position Pw is about to become the upper flip position Pu. In addition, the drive unit 62 determines whether the wiper angle θw obtained in step S100 is greater than 2×θmax-Δ and less than 2×θmax. Thus, the drive unit 62 determines whether the wiper position Pw is about to become the lower flip position Pd. It should be noted that Δ is set through experiments or simulations to determine whether the wiper position Pw is about to become the lower flip position Pd or the upper flip position Pu. For example, Δ is 1 to 10 degrees.

[0052] Furthermore, when the wiper angle θw is less than θmax-Δ or is θmax, since the wiper position Pw is not about to become the upturned position Pu, the process of the drive unit 62 is transferred to step S106. In addition, when the wiper angle θw is greater than θmax and less than 2×θmax-Δ or is 2×θmax, since the wiper position Pw is not about to become the downturned position Pd, the process of the drive unit 62 is transferred to step S106. In addition, when the wiper angle θw is greater than θmax-Δ and less than θmax, since the wiper position Pw is about to become the upturned position Pu, the process of the drive unit 62 is transferred to step S108. In addition, when the wiper angle θw is greater than 2×θmax-Δ and less than 2×θmax, since the wiper position Pw is about to become the downturned position Pd, the process of the drive unit 62 is transferred to step S108.

[0053] In step S106 subsequent to step S104, driving unit 62 turns on Hi switch 35 or Lo switch 45. As a result, wiper motor 100 rotates, and wiper 90 is driven.

[0054] Here, for example, it is assumed that, through the operation of the operator, the wiper switch 16 outputs a signal to the drive unit 62 that causes the operating state of the wiper 90 to be the continuous high-speed mode. At this time, the drive unit 62 turns on the Hi switch 35. Therefore, a voltage is applied to the wiper motor 100 from the motor power supply 14 via the Hi switch 35, the Hi wiring 37, the Hi current detection unit 39, and the Hi terminal 104. As a result, the wiper motor 100 rotates at a higher speed than when the Lo terminal 106 is energized. Therefore, by the wiper 90 connected to the wiper motor 100 rotating at a high speed, the operating state of the wiper 90 is changed to the continuous high-speed mode. It should be noted that, at this time, the Lo switch 45 is disconnected.

[0055] In addition, for example, it is assumed that the wiper switch 16 outputs a signal to the drive unit 62 that the operating state of the wiper 90 is a continuous low-speed mode through the operation of the operator. At this time, the drive unit 62 turns on the Lo switch 45. Therefore, a voltage is applied to the wiper motor 100 from the motor power supply 14 via the Lo switch 45, the Lo wiring 47, the Lo current detection unit 49 and the Lo terminal 106. As a result, the wiper motor 100 rotates at a lower speed than when the Hi terminal 104 is energized. Therefore, by the wiper 90 connected to the wiper motor 100 rotating at a low speed, the operating state of the wiper 90 becomes a continuous low-speed mode. It should be noted that at this time, the Hi switch 35 is disconnected. In addition, when the operating state of the wiper 90 is an intermittent mode, the drive unit 62 turns on the Lo switch 45. As a result, the wiper motor 100 rotates at a low speed. In addition, when the wiper 90 reciprocates between the lower flip position Pd and the upper flip position Pu and the wiper position Pw is at the lower flip position Pd, the drive unit 62 turns off the Lo switch 45. Therefore, since the wiper motor 100 is temporarily stopped, the wiper 90 is temporarily stopped. Thereafter, the drive unit 62 turns on the Lo switch 45. As a result, the wiper motor 100 rotates at a low speed. Therefore, through these actions, the wiper 90 intermittently reciprocates between the lower flip position Pd and the upper flip position Pu.

[0056] After the drive unit 62 controls the Hi switch 35 and the Lo switch 45 in this manner, the process of the drive unit 62 returns to step S100 .

[0057] In step S108 following step S104, the wiper position Pw is about to become the lower flip position Pd or the upper flip position Pu. Therefore, in step S108, the drive unit 62 performs PWM control on the wiper motor 100 by performing 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. As a result, the wiper 90 moves smoothly to the lower flip position Pd or the upper flip position Pu by decelerating. Therefore, for example, the operating sound of the wiper 90 generated when the wiper position Pw is the lower flip position Pd or the upper flip position Pu is reduced. It should be noted that PWM is the abbreviation of Pulse Width Modulation.

[0058] Specifically, when the operation state of the wiper 90 is the continuous high-speed mode, the drive unit 62 repeats the following operation: after turning on the Hi switch 35 for the first time for Hi, the Hi switch 35 is turned off for the second time for Hi. In addition, when the operation state of the wiper 90 is the continuous low-speed mode, the drive unit 62 repeats the following operation: after turning on the Lo switch 45 for the first time for Lo, the Lo switch 45 is turned off for the second time for Lo. Through these operations, the power supplied to the wiper motor 100 is reduced, so the wiper 90 is decelerated. Therefore, the drive of the wiper 90 becomes smooth. In addition, when the wiper 90 stops, the wiper 90 stops smoothly at the lower flip position Pd. It should be noted that the Hi first time, the Hi second time, the Lo first time, and the Lo second time are set through experiments or simulations, etc., so that the power supplied to the wiper motor 100 is reduced and the drive of the wiper 90 becomes smooth. Furthermore, by changing the Hi first time, the Hi second time, the Lo first time, and the Lo second time, the electric power supplied to the wiper motor 100 is gradually changed, thereby making the operation of the wiper 90 smoother.

[0059] In this way, after the drive unit 62 performs the on / off control of one of the Hi switch 35 and the Lo switch 45 , the process of the drive unit 62 returns to step S100 .

[0060] As described above, the drive unit 62 controls the voltage applied to the wiper motor 100. Figure 6 : The control unit 60 executes the program to estimate the wiper angle θw by the estimation unit 64. It should be noted that the period from the start of the processing of step S200 of the estimation unit 64 to the return to the processing of step S200 is the control cycle τ of the estimation unit 64.

[0061] In step S200, the estimation unit 64 obtains various information. Specifically, the estimation unit 64 obtains the following signal from the wiper switch 16, which causes the operation state of the wiper 90 to change to a continuous high-speed mode, a continuous low-speed mode, an intermittent mode, and a stop. In addition, the estimation unit 64 obtains the temperature of the wiper motor 100 from the motor temperature estimation unit 61. In addition, the estimation unit 64 obtains the Hi current Im_Hi from the Hi current detection unit 39. In addition, the estimation unit 64 obtains the Lo current Im_Lo from the Lo current detection unit 49. In addition, the estimation unit 64 obtains the torque of the wiper motor 100 from a torque estimation device not shown in the figure. It should be noted that in the torque estimation device, the torque of the wiper motor 100 is estimated, for example, by the state of the windshield not shown in the figure, the vehicle speed, and the power of the wiper motor 100.

[0062] Here, for example, it is assumed that the operating state of the wiper 90 is the continuous high-speed mode. At this time, the Hi switch 35 is turned on. Therefore, a voltage is applied to the wiper motor 100 from the motor power supply 14 via the Hi switch 35, the Hi wiring 37, the Hi current detection unit 39, and the Hi terminal 104. As a result, current flows to the wiper motor 100 and the wiper motor 100 rotates, so the Hi current Im_Hi includes a current ripple Ir. Therefore, the Hi current Im_Hi changes periodically.

[0063] In addition, for example, it is assumed that the operating state of the wiper 90 is the continuous low-speed mode or the intermittent mode. At this time, the Lo switch 45 is turned on. Therefore, a voltage is applied to the wiper motor 100 from the motor power supply 14 via the Lo switch 45, the Lo wiring 47, the Lo current detection unit 49, and the Lo terminal 106. As a result, current flows to the wiper motor 100 and the wiper motor 100 rotates, so the Lo current Im_Lo includes a current ripple Ir. Therefore, the Lo current Im_Lo changes periodically.

[0064] As described above, current ripple Ir is generated by the contact and non-contact between the commutator and the brush of the wiper motor 100. In addition, the number of times when the change amount ΔIm during the movement of the wiper 90 from the lower flip position Pd to the upper flip position Pu and from the upper flip position Pu to the lower flip position Pd is greater than the change threshold ΔIm_th is uniquely determined by the structure of the wiper motor 100. Therefore, by summing the number of times when the change amount ΔIm is greater than the change threshold ΔIm_th as the pulse number N, the wiper angle θw can be estimated.

[0065] In addition, since the current flowing to the wiper motor 100 changes with the change of the voltage applied to the wiper motor 100, the current ripple Ir and the change amount ΔIm change. In addition, the current ripple Ir and the change amount ΔIm change with the change of the temperature of the wiper motor 100. In addition, the current ripple Ir and the change amount ΔIm change with the change of the torque of the wiper motor 100. Therefore, it is preferable to change the change threshold ΔIm_th according to the voltage applied to the wiper motor 100, the temperature of the wiper motor 100, and the torque of the wiper motor 100.

[0066] Therefore, if Figure 6 As shown in the flowchart of, in step S202 following step S200, as Figure 7 As shown, the estimation unit 64 calculates the change amount ΔIm. In addition, the estimation unit 64 calculates the change threshold ΔIm_th.

[0067] For example, assume that the wiper 90 is in the continuous high-speed mode. In this case, the estimation unit 64 calculates the difference between the Hi current Im_Hi(n) in the current control cycle τ(n) and the Hi current Im_Hi(n-1) in the previous control cycle τ(n-1). Thus, the estimation unit 64 calculates the change ΔIm. It should be noted that the change ΔIm may also be the absolute value of the above difference.

[0068] For example, it is assumed that the wiper 90 is in the continuous low speed mode or the intermittent mode. In this case, the estimation unit 64 calculates the difference between the Lo current Im_Lo(n) in the current control cycle τ(n) and the Lo current Im_Lo(n-1) in the previous control cycle τ(n-1). Thus, the estimation unit 64 calculates the change ΔIm.

[0069] Furthermore, the estimation unit 64 calculates the change threshold value ΔIm_th based on the temperature of the wiper motor 100, the voltage applied to the wiper motor 100, and the torque of the wiper motor 100 obtained in step S200. Specifically, the estimation unit 64 calculates the change threshold value ΔIm_th by using the temperature of the wiper motor 100, the voltage applied to the wiper motor 100, the torque of the wiper motor 100, and the map. It should be noted that the map used to calculate the change threshold value ΔIm_th is set, for example, so that the change threshold value ΔIm_th increases as the temperature of the wiper motor 100 decreases. Furthermore, the map used to calculate the change threshold value ΔIm_th is set, for example, so that the change threshold value ΔIm_th increases as the voltage applied to the wiper motor 100 increases. Furthermore, the map used to calculate the change threshold value ΔIm_th is set, for example, so that the change threshold value ΔIm_th increases as the torque of the wiper motor 100 increases.

[0070] return Figure 6 Then, in step S204, the estimation unit 64 determines whether the change amount ΔIm calculated in step S202 is greater than the change threshold ΔIm_th. If the change amount ΔIm is greater than the change threshold ΔIm_th, the processing of the estimation unit 64 is transferred to step S206. If the change amount ΔIm is less than the change threshold ΔIm_th, the processing of the estimation unit 64 is transferred to step S208.

[0071] In step S206 following step S204, the change amount ΔIm is greater than the change threshold ΔIm_th. Therefore, at this time, the estimation unit 64 calculates the number of pulses N(n) in the current control cycle τ(n) by adding 1 to the number of pulses N(n-1) in the previous control cycle τ(n-1).

[0072] In step S208 following step S204 , the change amount ΔIm is smaller than the change threshold ΔIm_th. Therefore, at this time, the estimation unit 64 sets the number of pulses N(n) in the current control cycle τ(N) to the number of pulses N(n-1) in the previous control cycle τ(n-1).

[0073] Here, as described above, the rotation angle of wiper motor 100 can be estimated based on the number of times when change amount ΔIm is equal to or greater than change threshold value ΔIm_th, that is, pulse number N, and therefore wiper angle θw can be estimated.

[0074] Therefore, in step S210, the estimation unit 64 estimates the wiper angle θw based on the number of pulses N(n) in the current control cycle τ(n) calculated above and the mapping. In addition, the estimation unit 64 outputs a signal corresponding to the estimated wiper angle θw to the drive unit 62. Thereafter, the processing of the estimation unit 64 returns to step S200. It should be noted that the mapping used to estimate the wiper angle θw based on the number of pulses N is set by the characteristics of the linkage mechanism and the wiper motor 100, which are not shown in the figure, experiments or simulations, etc. For example, it is assumed that the number of pulses N when the wiper 90 reciprocates between the lower flip position Pd and the upper flip position Pu is 1000 times. In this case, for example, when the number of pulses N(n) in the current control cycle τ(n) is 500 times, the wiper angle θw is estimated to be the maximum angle θmax, and the wiper position Pw is estimated to be the upper flip position Pu. In this case, for example, when the number of pulses N(n) in the current control cycle τ(n) is 1000, the wiper angle θw is estimated to be 2×θmax, and the wiper position Pw is estimated to be the downward flip position Pd. It should be noted that the number of pulses N may also be reset at this time.

[0075] As described above, the estimation unit 64 estimates the wiper angle θw. Next, in the wiper control device 30, estimation of the wiper angle θw with a simple configuration will be described.

[0076] In step S200, the estimation unit 64 functions as an acquisition unit that acquires a value related to the current flowing to the wiper motor 100. In addition, in step S210, the estimation unit 64 estimates the wiper angle θw based on the current ripple Ir, which is a current ripple in the current flowing to the wiper motor 100 that has a periodicity corresponding to the driving of the wiper motor 100. It should be noted that the wiper motor 100 drives the wiper 90. The wiper 90 reciprocates between the lower flip position Pd and the upper flip position Pu. The lower flip position Pd is equivalent to the first position. The upper flip position Pu is equivalent to the second position. The wiper angle θw is the rotation angle of the wiper 90.

[0077] Thus, the wiper angle θw can be estimated without providing a Hall sensor for detecting the rotor speed. Therefore, it is not necessary to provide signal wiring for the Hall sensor. Therefore, the wiper angle θw can be estimated with a simple structure. In addition, here, the wiper position Pw can sometimes be estimated by a cam switch, which is turned on and off according to the rotation of the wiper motor 100. In this regard, the wiper control device 30 of this embodiment does not need to have a cam switch because it estimates the wiper position Pw by the above-mentioned structure.

[0078] In addition, as described in the Japanese Patent Gazette No. 10-105246, it is known that the current rotation position and rotation speed of the motor can be obtained based on the current ripple pulses in the motor current and the polarity of the motor current flipped by the rotation direction of the motor. In this regard, the wiper control device 30 of the present embodiment estimates the wiper angle θw based on the current ripple Ir. Therefore, the wiper control device 30 is different from the invention described in the Japanese Patent Gazette No. 10-105246. In addition, the wiper control device 30 of the present embodiment has the advantageous effect of being able to estimate the wiper angle θw, which is different from the invention described in the Japanese Patent Gazette No. 10-105246. Therefore, the wiper control device 30 has novelty and creativity.

[0079] Furthermore, the wiper control device 30 of the present embodiment also exhibits the following effects.

[0080] The estimation unit 64 estimates the wiper angle θw based on the pulse number N. This makes it easy to estimate the wiper angle θw. The pulse number N corresponds to the number of times the absolute value of the change amount ΔIm of the current flowing through the wiper motor 100 is equal to or greater than the change threshold ΔIm_th.

[0081] Here, as described above, since the current flowing to the wiper motor 100 changes with the change of the voltage applied to the wiper motor 100, the current ripple Ir and the change amount ΔIm change. In addition, the current ripple Ir and the change amount ΔIm change with the change of the temperature of the wiper motor 100. In addition, the current ripple Ir and the change amount ΔIm change with the change of the torque of the wiper motor 100.

[0082] In response to this, the estimation unit 64 changes the change threshold value ΔIm_th in step S202 in accordance with the change in the voltage of the wiper motor 100. In addition, the estimation unit 64 changes the change threshold value ΔIm_th in step S202 in accordance with the change in the temperature of the wiper motor 100. In addition, the estimation unit 64 changes the change threshold value ΔIm_th in step S202 in accordance with the change in the torque of the wiper motor 100.

[0083] As a result, the calculation accuracy of the pulse number N calculated by comparing the change amount ΔIm with the change threshold value ΔIm_th is improved. Therefore, the estimation accuracy of the wiper angle θw is improved.

[0084] The wiper control device 30 further includes a Hi current detection unit 39 and a Hi switching unit 41. The Hi current detection unit 39 detects the Hi current Im_Hi. The Hi switching unit 41 switches the detection range of the current detected by the Hi current detection unit 39. In addition, when the Hi current Im_Hi is greater than the Hi protection threshold Im_Hi_th, the Hi switching unit 41 makes the Hi current detection range greater than the detection range when the Hi current Im_Hi is less than the Hi protection threshold Im_Hi_th. In addition, when the Hi current Im_Hi is less than the Hi protection threshold Im_Hi_th, the Hi switching unit 41 makes the Hi current detection range less than the detection range when the Hi current Im_Hi is greater than the Hi protection threshold Im_Hi_th.

[0085] Thus, when the Hi current Im_Hi is greater than the Hi protection threshold Im_Hi_th, the Hi current detection unit 39 can detect a relatively large Hi current Im_Hi. Therefore, it is possible to detect abnormal heating of the Hi wiring 37, the wiper motor 100, and the wiper 90 caused by the relatively large Hi current Im_Hi. In addition, when the Hi current Im_Hi is less than the Hi protection threshold Im_Hi_th, the Hi current detection unit 39 can detect the Hi current Im_Hi with high accuracy due to the high resolution. Therefore, since the detection accuracy of the current ripple Ir is improved, the calculation accuracy of the pulse number N is also improved. Therefore, the estimation accuracy of the wiper angle θw is also improved.

[0086] In addition, the wiper control device 30 further includes a Lo current detection unit 49 and a Lo switching unit 51. The Lo current detection unit 49 detects the Lo current Im_Lo. The Lo switching unit 51 switches the detection range of the current detected by the Lo current detection unit 49. In addition, when the Lo current Im_Lo is greater than the Lo protection threshold Im_Lo_th, the Lo switching unit 51 makes the Lo current detection range greater than the detection range when the Lo current Im_Lo is less than the Lo protection threshold Im_Lo_th. In addition, when the Lo current Im_Lo is less than the Lo protection threshold Im_Lo_th, the Lo switching unit 51 makes the Lo current detection range less than the detection range when the Lo current Im_Lo is greater than the Lo protection threshold Im_Lo_th.

[0087] Thus, when the Lo current Im_Lo is greater than the Lo protection threshold Im_Lo_th, the Lo current detection unit 49 can detect a relatively large Lo current Im_Lo. Therefore, it is possible to detect abnormal heating of the Lo wiring 47, the wiper motor 100, and the wiper 90 caused by the relatively large Lo current Im_Lo. In addition, when the Lo current Im_Lo is less than the Lo protection threshold Im_Lo_th, the Lo current detection unit 49 can detect the Lo current Im_Lo with high accuracy due to the high resolution. Therefore, since the detection accuracy of the current ripple Ir is improved, the calculation accuracy of the pulse number N is also improved. Therefore, the estimation accuracy of the wiper angle θw is also improved.

[0088] In either the case where the wiper position Pw is about to be changed to the downward reversal position Pd or the case where the wiper position Pw is about to be changed to the upward reversal position Pu, the drive unit 62 reduces the electric power supplied to the wiper motor 100 .

[0089] Thus, the wiper 90 is decelerated when it is about to change to the downward flip position Pd or the upward flip position Pu, so as to smoothly move to the downward flip position Pd or the upward flip position Pu. Therefore, it is possible to prevent the wiper 90 from excessively moving without stopping at the downward flip position Pd or the upward flip position Pu, that is, it is possible to prevent the wiper 90 from overrunning. In addition, the operating sound of the wiper 90 generated when the wiper position Pw is the downward flip position Pd or the upward flip position Pu is reduced.

[0090] (Variant 1)

[0091] In the above embodiment, the driving unit 62 controls the on / off of the Hi switch 35 or the Lo switch 45 in step S108. As a result, the driving unit 62 reduces the power supplied to the wiper motor 100. In this regard, the means for reducing the power supplied to the wiper motor 100 by the driving unit 62 is not limited to the above-mentioned on / off control. For example, the driving unit 62 may also reduce the power supplied to the wiper motor 100 by controlling a DCDC converter (not shown) connected to the motor power supply 14 to reduce the voltage applied from the motor power supply 14 to the wiper motor 100.

[0092] In addition, in the above embodiment, the estimation unit 64 may output a signal corresponding to the wiper angle θw estimated in step S210 to an external device. Figure 8 As shown, the external device is a washer device 70. The washer device 70 controls the timing of spraying the washer fluid for washing the windshield (not shown) based on the signal from the estimation unit 64. For example, the washer device 70 sprays the washer fluid when the wiper angle θw estimated by the estimation unit 64 is zero or 2×θmax, that is, when the wiper position Pw is the downward flip position Pd.

[0093] In the above embodiment, the estimation unit 64 calculates the number of times when the change amount ΔIm is greater than the change threshold ΔIm_th as the pulse number N. In this regard, the pulse number N is not limited to the number of times when the change amount ΔIm is greater than the change threshold ΔIm_th. Fig. 9 As shown, the estimation unit 64 may also calculate the number of times when the current flowing to the wiper motor 100 changes from less than the current threshold Im_th to more than the current threshold Im_th as the pulse number N. In addition, the estimation unit 64 may also calculate the number of times when the current flowing to the wiper motor 100 changes from more than the current threshold Im_th to less than the current threshold Im_th as the pulse number N. It should be noted that the current threshold Im_th is, for example, the same as the change threshold ΔIm_th, and can be calculated based on the temperature of the wiper motor 100, the voltage applied to the wiper motor 100, and the torque of the wiper motor 100.

[0094] In addition, in the above-mentioned embodiment, the Hi switching unit 41 switches the Hi current detection range to either the Hi first detection range or the Hi second detection range based on the Hi current Im_Hi. In this regard, the Hi switching unit 41 may also switch the Hi current detection range to either the Hi first detection range or the Hi second detection range without depending on the Hi current Im_Hi. For example, the Hi switching unit 41 may also switch the Hi current detection range alternately to the Hi first detection range and the Hi second detection range as time passes. Similarly, the Lo switching unit 51 may also switch the Lo current detection range to either the Lo first detection range or the Lo second detection range without depending on the Lo current Im_Lo. For example, the Lo switching unit 51 may also switch the Lo current detection range alternately to the Lo first detection range and the Lo second detection range as time passes.

[0095] In addition, in the above-mentioned embodiment, the Hi switch 35, the Hi current detection unit 39, the Lo switch 45, and the Lo current detection unit 49 are independent. In contrast, the Hi switch 35 and the Hi current detection unit 39 may be integrated. In addition, the Lo switch 45 and the Lo current detection unit 49 may be integrated. In addition, the Hi switch 35, the Hi current detection unit 39, the Lo switch 45, and the Lo current detection unit 49 may be integrated.

[0096] (Variant 2)

[0097] In the above embodiment, the driving unit 62 performs PWM control on the wiper motor 100 by turning on and off the Hi switch 35 or the Lo switch 45 in step S108. This can prevent the wiper 90 from exceeding the limit without stopping at the lower reversal position Pd or the upper reversal position Pu.

[0098] In contrast, the wiper motor 100 of the second modification is a permanent magnet field type DC commutator motor, and for example, a multi-speed motor as known in the Japanese Patent Publication No. 10-503640 can be used, which changes the current circuit for the armature by selecting and switching the low-speed brush and the high-speed brush, so that the rotation of the motor can be switched between low speed and high speed. Specifically, at least one pair of permanent magnets is fixed to the inner surface of the motor yoke (not shown), and the winding is installed on the core of the armature by overlapping winding, for example, and the Hi terminal 104, the Lo terminal 106, and the GND terminal 108 as the brush are arranged on the commutator in a slidable contact. Since the Hi terminal 104 is arranged at a position more forward than the Lo terminal 106, when the Hi terminal 104 is selected and power is supplied, the rotation speed of the motor can be set to a higher speed than the rotation speed when the Lo terminal 106 is selected. Thus, the wiper motor 100 of the second modification can be driven to rotate at a low speed or a high speed by selectively switching the Hi terminal 104 or the Lo terminal 106 and supplying power without PWM control. When the wiper motor 100 of the second modification is used, if the Hi switch 35 is turned on, when the wiper position Pw is about to change to the upward flip position Pu, for example, the wiper angle θw is set to θmax-Δ. At this time, if Fig.10 As shown, the drive unit 62 changes the Hi switch 35 from on to off. As a result, the drive unit 62 stops supplying power to the Hi terminal 104. In addition, at this time, the drive unit 62 changes the Lo switch 45 from off to on. As a result, the drive unit 62 supplies power to the Lo terminal 106. It should be noted that the speed of the motor when the Hi terminal 104 is selected is a higher speed than the speed of the motor when the Lo terminal 106 is selected, which is equivalent to the first speed. In addition, the speed of the motor when the Lo terminal 106 is selected is a lower speed than the speed of the motor when the Hi terminal 104 is selected, which is equivalent to the second speed.

[0099] Furthermore, when the wiper position Pw changes from the position about to change to the upturned position Pu to the upturned position Pu, here, when the wiper angle θw changes from θmax-Δ to θmax, the drive unit 62 changes the Hi switch 35 from off to on. Thus, the drive unit 62 supplies power to the Hi terminal 104. Moreover, at this time, the drive unit 62 changes the Lo switch 45 from on to off. Thus, the drive unit 62 stops supplying power to the Lo terminal 106.

[0100] In addition, when the Hi switch 35 is turned on, when the wiper position Pw is about to change to the downward flip position Pd, for example, the wiper angle θw is set to 2×θmax-Δ. At this time, the drive unit 62 turns the Hi switch 35 from on to off. As a result, the drive unit 62 stops supplying power to the Hi terminal 104. In addition, at this time, the drive unit 62 turns the Lo switch 45 from off to on. As a result, the drive unit 62 supplies power to the Lo terminal 106.

[0101] Furthermore, when the wiper position Pw changes from the position about to change to the downward flip position Pd to the downward flip position Pd, here, when the wiper angle θw changes from 2×θmax-Δ to 2×θmax, the drive unit 62 changes the Hi switch 35 from being turned off to being turned on. Thus, the drive unit 62 supplies power to the Hi terminal 104. Moreover, at this time, the drive unit 62 changes the Lo switch 45 from being turned on to being turned off. Thus, the drive unit 62 stops supplying power to the Lo terminal 106.

[0102] By such processing of the driving unit 62, the wiper 90 is decelerated when about to be changed to the downward flip position Pd or the upward flip position Pu, so as to smoothly move to the downward flip position Pd or the upward flip position Pu. Therefore, the overrun of the wiper 90 is suppressed. In addition, the operating sound of the wiper 90 generated when the wiper position Pw is the downward flip position Pd or the upward flip position Pu is reduced.

[0103] In the above-mentioned process of the driving unit 62, the driving unit 62 turns the Lo switch 45 on and off. Fig.11 As shown, the drive unit 62 may not turn on the Lo switch 45 but keep it off when the wiper angle θw is greater than θmax-Δ and less than θmax. In addition, the drive unit 62 may not turn on the Lo switch 45 but keep it off when the wiper angle θw is greater than 2×θmax-Δ and less than 2×θmax.

[0104] By such processing of the driving unit 62, the wiper 90 is decelerated just before the downward flip position Pd or the upward flip position Pu, and moves smoothly to the downward flip position Pd or the upward flip position Pu. Therefore, overrunning and operation noise of the wiper 90 are suppressed.

[0105] It should be noted that in the above-mentioned modification 2, the Hi terminal 104 is equivalent to the first terminal for supplying power. The Lo terminal 106 is equivalent to the second terminal, and the power supplied to the second terminal is less than the power supplied to the first terminal. The Hi switch 35 is equivalent to the first element, which is turned on to allow current to flow to the wiper motor via the first terminal, thereby rotating the wiper motor. The Lo switch 45 is equivalent to the second element, which is turned on to allow current to flow to the wiper motor via the second terminal, thereby rotating the wiper motor.

[0106] Here, as described in Japanese Patent Application Laid-Open No. 2007-237921, there is known a wiper device that controls a driving means so that the angular velocity and angular acceleration of the wiper rotation axis at the flip position of the wiper arm become zero.

[0107] In this wiper device, a sensor for detecting the angular velocity and angular acceleration of the wiper rotation shaft is required, and thus, the number of components of the wiper device increases, and the cost of the wiper device increases.

[0108] In contrast, in the above-described embodiment, Modification 1, and Modification 2, the overrun and operating noise of the wiper 90 can be suppressed without using a sensor for detecting the angular velocity and angular acceleration of the wiper 90. Therefore, in the above-described embodiment, Modification 1, and Modification 2, since the increase in the number of components of the wiper control device 30 is suppressed, the increase in the cost of the wiper control device 30 can be suppressed, and at the same time, the overrun and operating noise of the wiper 90 can be suppressed.

[0109] (Other embodiments)

[0110] The present disclosure is not limited to the above-mentioned embodiments, and the above-mentioned embodiments can be appropriately changed. In addition, it is understood that in the above-mentioned embodiments, the elements constituting the embodiments are not necessarily required, except for the cases that are specifically indicated as required and the cases that are obviously considered to be required in principle.

[0111] The acquisition unit, inference unit, driving unit and method thereof described in the present disclosure may also be implemented by a dedicated computer provided by a processor and a memory configured as follows, and the processor and the memory are programmed to execute one or more functions concretized by a computer program. Alternatively, the acquisition unit, inference unit, driving unit and method thereof described in the present disclosure may also be implemented by a dedicated computer provided by a processor configured by one or more dedicated hardware logic circuits. Alternatively, the acquisition unit, inference unit, driving unit and method thereof described in the present disclosure may also be implemented by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions, and a processor configured by one or more hardware logic circuits. In addition, a computer program may also be stored as an instruction executed by a computer in a non-migratable tangible storage medium readable by a computer.

[0112] The above-described embodiment and each of the above-described modifications may be combined as appropriate.

Claims

1. A wiper control device, wherein: have: an acquisition unit that acquires a value related to a current flowing to a wiper motor that drives a wiper to and fro between a first position and a second position; an estimating unit that estimates a wiper angle as a rotation angle of the wiper based on a current ripple that is a current ripple having a periodicity corresponding to driving of the wiper motor in a current flowing to the wiper motor; as well as The driving unit reduces the power supplied to the wiper motor in either a case where the position of the wiper is about to be changed to the first position or a case where the position of the wiper is about to be changed to the second position.

2. The wiper control device according to claim 1, wherein: The wiper motor further comprises a driving element which, when turned on, causes current to flow to the wiper motor, thereby rotating the wiper motor. In either a case where the wiper position is about to be changed to the first position or a case where the wiper position is about to be changed to the second position, the driving unit turns on and off the driving element to reduce the power supplied to the wiper motor.

3. A wiper control device, wherein: have: an acquisition unit that acquires a value related to a current flowing to a wiper motor that drives a wiper to and fro between a first position and a second position; and an estimating unit that estimates a wiper angle as a rotation angle of the wiper based on a current ripple that is a current ripple having a periodicity corresponding to driving of the wiper motor in a current flowing to the wiper motor, The wiper motor has: a first terminal to which power is supplied so that the wiper motor rotates at a first speed; as well as a second terminal to which power is supplied so that the wiper motor rotates at a second speed lower than the first speed, The wiper control device further comprises: a first element, wherein the first element is turned on to allow current to flow to the wiper motor via the first terminal, thereby rotating the wiper motor; a second element, wherein the second element, when turned on, causes current to flow to the wiper motor via the second terminal, thereby rotating the wiper motor; as well as a driving unit, the driving unit controlling the on and off of the first element and the second element, When the first element is turned on, if the position of the wiper is about to be changed to the first position or the position of the wiper is about to be changed to the second position, the driving unit stops the power supply to the first terminal by turning the first element from on to off, and supplies power to the second terminal by turning the second element from off to on. In either case, if the wiper position changes from about to change to the first position to the first position, or changes from about to change to the second position to the second position, the drive unit supplies power to the first terminal by changing the first element from off to on, and stops the power supply to the second terminal by changing the second element from on to off.

4. A wiper control device, wherein: have: an acquisition unit that acquires a value related to a current flowing to a wiper motor that drives a wiper to and fro between a first position and a second position; and an estimating unit that estimates a wiper angle as a rotation angle of the wiper based on a current ripple that is a current ripple having a periodicity corresponding to driving of the wiper motor in a current flowing to the wiper motor, The wiper motor has: a first terminal to which power is supplied so that the wiper motor rotates at a first speed; as well as a second terminal to which power is supplied so that the wiper motor rotates at a second speed lower than the first speed, The wiper control device further comprises: a first element, wherein the first element is turned on to allow current to flow to the wiper motor via the first terminal, thereby rotating the wiper motor; a second element, wherein the second element is turned on to allow current to flow to the wiper motor via the second terminal, thereby rotating the wiper motor; as well as a driving unit, the driving unit controlling the on and off of the first element and the second element, When the first element is turned on, if the wiper is about to be in the first position or the wiper is about to be in the second position, the driving unit turns the first element from on to off, thereby stopping the power supply to the first terminal and keeping the second element off. In either case, if the wiper position changes from about to change to the first position to the first position, or changes from about to change to the second position to the second position, the drive unit supplies power to the first terminal by changing the first element from off to on, thereby keeping the second element off.

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