Wiper control device

Abstract

To provide a wiper control device that estimates a rotation angle of a wiper with a simple configuration and suppresses overrun of the wiper.SOLUTION: A calculation unit 66 of a wiper control device 30 calculates a deceleration start angle on the basis of a ripple period, which is a period of a current ripple. A drive unit 62 turns off a Hi switch 35 or a Lo switch 45 that is turned on when a wiper angle reaches the deceleration start angle. Accordingly, the drive unit 62 decelerates the wiper by stopping power supply from the Hi switch 35 or Lo switch 45 to a wiper motor 100. Further, after the wiper angle reaches the deceleration start angle, when a wiper position is any of a lower reversal position, a position before the lower reversal position, an upper reversal position, or a position before the upper reversal position, the drive unit 62 turns on the Hi switch 35 or Lo switch 45 that was turned off, thereby resuming power supply to the wiper motor 100.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] A conventional wiper control method is known, as described in Patent Document 1, in which a wiper arm is driven in a forward and reverse direction to perform a reciprocating wipe between an upper reversal position and a lower reversal position using an electric motor. In this control method, the wiper arm is decelerated from a braking start position calculated based on the speed and load of the wiper arm near at least one of the reversal positions toward the reversal positions. The speed of the wiper arm is detected based on the motor pulse period output as the electric motor rotates. The motor pulses are output from a Hall IC for detecting the electric motor position, and consist of six pulses per rotation of the electric motor's rotary shaft. The electric motor is pulse-driven using a pulse-width modulation method, and the load on the wiper arm is detected based on the ratio of the on-time to the off-time of the pulse. The braking start position of the wiper arm is determined by a map that uses the speed and load of the wiper arm as parameters. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-196195 Summary of the Invention [Problem to be solved by the invention]

[0004] The wiper device control method described in Patent Document 1 requires a Hall IC for detecting the position of the electric motor to detect the speed of the wiper arm. This requires wiring for the Hall IC for detecting the position of the electric motor, which complicates the configuration of the wiper device described in Patent Document 1. Furthermore, when the wiper arm operates, if the wiper arm has a certain speed due to inertia at the upper or lower reversal position, overrun may occur, in which the wiper arm passes the upper or lower reversal position targeted by the design. There is also a need to suppress this overrun.

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

[0006] The invention of claim 1 is a wiper control device, comprising: an element (35, 45) that rotates a wiper motor (100) by passing a current through the wiper motor (100) that drives a wiper (90) reciprocating between a first position (Pd) and a second position (Pu) when turned on; a drive unit (62) that controls the on / off of the element; an acquisition unit (S200) that acquires values ​​related to currents (Im_Hi, Im_Lo) flowing through the wiper motor; an estimation unit (S210) that estimates a wiper angle (θw) that is a rotation angle of the wiper based on a current ripple (Ir) that has periodicity corresponding to the drive of the wiper motor among the currents flowing through the wiper motor; and an estimation unit (S211) that estimates a wiper angle (θw) that is a rotation angle of the wiper based on a ripple period (T) that is a period of the current ripple. and a calculation unit (66) that calculates a deceleration start angle (θb), which is the wiper angle before the wiper position reaches the first position and the second position and at which the wiper starts to decelerate. When the element is on and the wiper angle reaches the deceleration start angle, the drive unit decelerates the wiper by stopping the power supply from the element to the wiper motor by switching the element from on to off, and when the wiper angle reaches the deceleration start angle, after the wiper angle reaches the deceleration start angle, the drive unit resumes the power supply from the element to the wiper motor by switching the element from off to on.

[0007] This allows the wiper angle to be estimated without providing a Hall IC for detecting the electric motor position. This eliminates the need for wiring for a Hall IC for detecting the electric motor position. Therefore, the wiper angle θw can be estimated with a simple configuration. In addition, the wiper is decelerated just before reaching the first or second position, allowing it to smoothly reverse direction at the first or second position. This prevents the wiper from overrunning, which occurs when the wiper passes the intended first or second position.

[0008] 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]

[0009] [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] FIG. 4 is a diagram illustrating the relationship between the wiper angle and the on / off states of the Hi switch and the Lo switch, for explaining the processing of the drive unit. [Figure 6] FIG. 4 is a diagram illustrating the relationship between the wiper angle and the on / off states of the Hi switch and the Lo switch, for explaining the processing of the drive unit. [Figure 7] 5 is a flowchart showing the processing of an estimation unit of the wiper control device. [Figure 8] FIG. 10 is a diagram for explaining calculation of the number of pulses by an estimation unit. [Figure 9] 4 is a flowchart showing the processing of a calculation unit of the wiper control device. [Figure 10] FIG. 10 is a relationship diagram between a ripple period and a deceleration start angle for explaining calculation of the deceleration start angle by a calculation unit. [Figure 11] FIG. 10 is a relationship diagram between a ripple period and a deceleration control time for explaining calculation of the deceleration control time by a calculation unit. [Figure 12] FIG. 10 is a diagram showing the relationship between the wiper angle and the on / off states of the Hi switch and the Lo switch, for explaining the processing of the drive unit of the wiper control device of the second embodiment. [Figure 13] FIG. 10 is a configuration diagram of a wiper drive system in which a wiper control device according to another embodiment is used. [Figure 14] 10 is a diagram for explaining calculation of the number of pulses by an estimation unit in a wiper control device according to another embodiment. FIG. [Figure 15] 10 is a relationship diagram between a ripple period and a deceleration control time for explaining calculation of the deceleration control time by a calculation unit in a wiper control device according to another embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] (First embodiment) The wiper control device of this embodiment estimates the rotation angle of the wiper with a simple configuration and suppresses overrun of the wiper. For example, this wiper control device is used in a wiper drive system of a vehicle. First, this wiper drive system will be described.

[0012] 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 .

[0013] 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 .

[0014] Furthermore, 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). During this operation, the wiper motor 100 repeatedly makes contact and disengages between the brushes and multiple commutator segments in the wiper motor's commutator. As a result, as shown in FIG. 3, the wiper motor 100 has a characteristic in which a current ripple Ir is generated in the current flowing through the wiper motor 100, the current ripple Ir fluctuating periodically in response to the operation of the wiper motor 100. The amplitude of the current ripple Ir is, for example, 1 to 2 A. Furthermore, the ripple period T, which is the period of the current ripple Ir, is, for example, approximately 1.64 ms. When a 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.

[0015] Furthermore, as shown in FIG. 2 , the rotation angle of the wiper 90 when reciprocating between the lower reversal position Pd and the upper reversal position Pu is defined as the wiper angle θw. 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, 100 degrees. Here, the value of the wiper angle θw is defined as being in the range of zero to 2×θmax. Furthermore, when the wiper angle θw is zero or 2×θmax, the wiper position Pw is defined as being at the lower reversal position Pd. When the wiper angle θw is θmax, the wiper position Pw is defined as being at the upper reversal position Pu. When 0<θw<θmax, the wiper 90 rotates from the lower reversal position Pd toward the upper reversal position Pu. When θmax<θw<2×θmax, the wiper 90 rotates from the upper reversal position Pu toward 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 stopped 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 a Hi wiring 37. The Hi switch 35 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 a Lo wire 47. The Lo switch 45 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, drive circuit, A / D converter, comparator circuit, DC-DC converter, low-pass filter, 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, an estimation unit 64, and a calculation unit 66 as functional blocks.

[0024] By executing its own program, the drive unit 62 controls the on / off of the Hi switch 35 and the Lo switch 45 based on signals from the wiper switch 16, an estimation unit 64 (described later), and a calculation unit 66 (described later). As a result, the drive unit 62 controls the voltage applied to the wiper motor 100. As a result, the operation 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 stop mode. In addition, when the wiper 90 moves to the lower reversal position Pd or the upper reversal position Pu, overrun of the wiper 90 is suppressed.

[0025] The estimation unit 64 executes the program of the estimation unit 64 to estimate the wiper angle θw based on the signal from the wiper switch 16, the Hi current Im_Hi, and the Lo current Im_Lo. Furthermore, the estimation unit 64 outputs a signal corresponding to the estimated wiper angle θw to the drive unit 62.

[0026] The calculation unit 66 executes its own program to calculate the ripple period T based on the signal from the estimation unit 64. The calculation unit 66 also calculates a deceleration start angle θb and a deceleration control time Tb based on the calculated ripple period T. The calculation unit 66 then outputs signals corresponding to the calculated deceleration start angle θb and deceleration control time Tb to the drive unit 62. The deceleration start angle θb is the wiper angle θw before the wiper position Pw reaches the lower reversal position Pd and the upper reversal position Pu, and is the wiper angle θw at which the drive unit 62 starts decelerating the wiper 90. The deceleration control time Tb is the time during which the drive unit 62 performs deceleration control of the wiper 90 from when the wiper angle θw reaches the deceleration start angle θb.

[0027] The wiper drive system 1 is configured as described above. Next, control of the voltage applied to the wiper motor 100 by the execution of the program of the drive unit 62 will be described with reference to the flowchart of Fig. 4. The program of the drive unit 62 is executed, for example, when the ignition or power supply of the vehicle (not shown) is turned on.

[0028] In step S100, the drive unit 62 acquires various information. Specifically, the drive unit 62 acquires a signal from the wiper switch 16 to set the operation state of the wiper 90 to the continuous high-speed mode, the continuous low-speed mode, or the intermittent mode. The drive unit 62 also acquires the wiper angle θw from the estimation unit 64. The drive unit 62 also acquires the deceleration start angle θb and the deceleration control time Tb from the calculation unit 66.

[0029] 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. Then, when the drive unit 62 acquires a signal in step S100 to change the operating state of the wiper 90 to the continuous high-speed mode, the continuous low-speed mode, or the intermittent mode, the drive unit 62 determines that the wiper switch 16 is on. Thereafter, the process of the drive unit 62 proceeds to step S104. On the other hand, when the drive unit 62 acquires a signal in step S100 to stop the operating state of the wiper 90, 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.

[0030] In step S104 following step S102, the drive unit 62 determines whether the wiper angle θw acquired in step S100 is the deceleration start angle θb. As a result, the drive unit 62 determines whether it is time to decelerate the wiper 90.

[0031] When the wiper angle θw is not the deceleration start angle θb, it is not time to decelerate the wiper 90, so the process of the drive unit 62 proceeds to step S106, where normal control, which will be described later, is performed. Furthermore, when the wiper angle θw is the deceleration start angle θb, it is time to decelerate the wiper 90, so the process of the drive unit 62 proceeds to step S108, where deceleration control, which will be described later, is performed.

[0032] In step S106 following step S104, the drive unit 62 performs normal control. Specifically, the drive unit 62 turns on the Hi switch 35 or the Lo switch 45. This causes the wiper motor 100 to rotate, thereby driving the wiper 90.

[0033] 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, 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 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.

[0034] 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, the Lo current detection unit 49, 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.

[0035] After the drive unit 62 performs normal control in this manner, the process of the drive unit 62 returns to step S100.

[0036] In step S108 following step S104, the wiper angle θw is the deceleration start angle θb. Therefore, in step S108, the drive unit 62 performs deceleration control.

[0037] Here, for example, assume that the wiper switch 16 is operated by the operator to output a signal to the drive unit 62 to change the operating state of the wiper 90 to the continuous high-speed mode. In this case, when the wiper angle θw is equal to the deceleration start angle θb, as shown in FIG. 5 , the drive unit 62 changes the Hi switch 35 from on to off. This causes the drive unit 62 to stop supplying power to the Hi terminal 104. At this time, the drive unit 62 also changes the Lo switch 45 from off to on. This causes the drive unit 62 to supply power to the Lo terminal 106.

[0038] Also, for example, suppose that the wiper switch 16 is operated by the operator to output a signal to the drive unit 62 to change the operating state of the wiper 90 to the continuous low speed mode. In this case, when the wiper angle θw is equal to the deceleration start angle θb, as shown in FIG. 6, the drive unit 62 changes the Lo switch 45 from on to off. This causes the drive unit 62 to stop supplying power to the Lo terminal 106. Note that the Hi switch 35 remains off.

[0039] By the process of the drive unit 62, the wiper 90 is decelerated immediately before the lower reversal position Pd or the upper reversal position Pu, and thus smoothly reverses at the lower reversal position Pd or the upper reversal position Pu. This suppresses overrun of the wiper 90. Furthermore, the operating noise of the wiper 90 generated when the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu is reduced. Thereafter, the process of the drive unit 62 proceeds to step S110.

[0040] 5, in step S110 following step S108, the drive unit 62 determines whether the deceleration control time Tb acquired in step S100 has elapsed since the wiper angle θw became the deceleration start angle θb. As a result, the drive unit 62 determines whether to return the deceleration control of step S108 to the normal control of step S106.

[0041] If the deceleration control time Tb has not elapsed, the deceleration control of step S108 continues. Furthermore, if the operation state of the wiper 90 is the continuous high-speed mode after the deceleration control time Tb has elapsed, the Hi switch 35 is returned from off to on, and the Lo switch 45 is returned from on to off, as shown in FIG. 5. Furthermore, if the operation state of the wiper 90 is the continuous low-speed mode after the deceleration control time Tb has elapsed, the Lo switch 45 is returned from off to on, as shown in FIG. 6. Furthermore, after the deceleration control time Tb has elapsed, the wiper position Pw is located at the lower reversal position Pd or the upper reversal position Pu. Therefore, the process of the drive unit 62 proceeds to step S106. As a result, the control of the drive unit 62 returns from the deceleration control of step S108 to the normal control of step S106. Therefore, power supply to the terminals corresponding to the switches that were turned off during the deceleration control time Tb is resumed.

[0042] As described above, the drive unit 62 controls the voltage applied to the wiper motor 100. Next, the estimation of the wiper angle θw by the execution of the program of the estimation unit 64 will be described with reference to the flowchart of FIG. 7. The program of the estimation unit 64 is executed, for example, when the ignition or power supply of the vehicle (not shown) is turned on. Furthermore, the period of a series of operations from when the processing of step S200 of the estimation unit 64 starts until when the processing returns to step S200 is defined as the control cycle τ of the estimation unit 64.

[0043] In step S200, the estimation unit 64 acquires various information. Specifically, the estimation 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 to stop. The estimation unit 64 also acquires the Hi current Im_Hi from the Hi current detection unit 39. The estimation unit 64 also acquires the Lo current Im_Lo from the Lo current detection unit 49.

[0044] For example, assume that the wiper 90 is in the continuous high-speed mode. At this time, the Hi switch 35 is turned on. 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, the Hi current detector 39, and the Hi terminal 104. As a result, a current flows through the wiper motor 100, causing the wiper motor 100 to rotate, and the Hi current Im_Hi includes a current ripple Ir. As a result, the Hi current Im_Hi fluctuates periodically.

[0045] Also, for example, assume that the operation 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, a current flows through the wiper motor 100, causing the wiper motor 100 to rotate, and the Lo current Im_Lo includes a current ripple Ir. Therefore, the Lo current Im_Lo fluctuates periodically.

[0046] Furthermore, as described above, a current ripple Ir is generated due to contact and non-contact between the commutator and the brush of the wiper motor 100. The number of times that the change amount ΔIm becomes equal to or greater than the change threshold value ΔIm_th while the wiper 90 moves from the lower reversal position Pd to the upper reversal position Pu and while the wiper 90 moves from the upper reversal position Pu to the lower reversal position Pd is uniquely determined by the structure of the wiper motor 100. Therefore, the number of times that the change amount ΔIm becomes equal to or greater than the change threshold value ΔIm_th is counted as the number of pulses N, thereby enabling estimation of the wiper angle θw.

[0047] Furthermore, since the current flowing through the wiper motor 100 changes as the voltage applied to the wiper motor 100 changes, the current ripple Ir and the change amount ΔIm change. Therefore, it is preferable to change the change threshold value ΔIm_th depending on the voltage applied to the wiper motor 100.

[0048] Therefore, in step S202 following step S200, the estimation unit 64 calculates the amount of change ΔIm as shown in Fig. 8. The estimation unit 64 also calculates a change threshold ΔIm_th.

[0049] 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). The estimation unit 64 then calculates the amount of change ΔIm. The amount of change ΔIm may be the absolute value of the difference.

[0050] Also, for example, assume 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). From this, the estimation unit 64 calculates the change amount ΔIm.

[0051] Furthermore, the estimation unit 64 calculates the change threshold value ΔIm_th based on the voltage applied to the wiper motor 100. For example, the estimation unit 64 increases the change threshold value ΔIm_th as the voltage applied to the wiper motor 100 increases.

[0052] 7, in step S204, the estimation unit 64 determines whether the change ΔIm calculated in step S202 is equal to or greater than the change threshold ΔIm_th. If the change ΔIm is equal to or greater than the change threshold ΔIm_th, the process by the estimation unit 64 proceeds to step S206. If the change ΔIm is less than the change threshold ΔIm_th, the process by the estimation unit 64 proceeds to step S208.

[0053] In step S206 following step S204, the change amount ΔIm is equal to or greater than the change threshold value ΔIm_th, so 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).

[0054] In step S208 following step S204, the change amount ΔIm is less than the change threshold ΔIm_th, so 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).

[0055] As described above, the rotation angle of the wiper motor 100 can be estimated from the number of times when the change amount ΔIm is equal to or greater than the change threshold value ΔIm_th, that is, the number of pulses N, and therefore the wiper angle θw can be estimated.

[0056] Therefore, in step S210, the estimation unit 64 estimates the wiper angle θw based on the wiper angle θw at which the number of pulses N changes per cycle and the calculated number of pulses N(n) in the current control cycle τ(n). Alternatively, the estimation unit 64 estimates the wiper angle θw based on the calculated number of pulses N(n) in the current control cycle τ(n) and a map. The estimation unit 64 then outputs a signal corresponding to the estimated wiper angle θw to the drive unit 62. The process of the estimation unit 64 then returns to step S200. The wiper angle θw at which the number of pulses N changes per cycle is calculated, for example, by dividing 2×θmax by the total number of pulses N when the wiper angle θw changes from 0 to 2×θmax, and is set in advance. The map for estimating the wiper angle θw from the number of pulses N is set based on the characteristics of the link mechanism and the wiper motor 100 (not shown), experiments, simulations, etc. For example, suppose the number of pulses N when the wiper 90 reciprocates between the lower reversal position Pd and the upper reversal position Pu is 1000. In this case, for example, when the number of pulses N(n) in the current control cycle τ(n) is 500, the wiper angle θw is estimated to be the maximum angle θmax, and the wiper position Pw is estimated to be the upper reversal position Pu. Furthermore, 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 lower reversal position Pd. At this time, the number of pulses N may be reset.

[0057] As described above, the estimation unit 64 estimates the wiper angle θw. Next, calculation of the ripple period T, the deceleration start angle θb, and the deceleration control time Tb by the program execution of the calculation unit 66 will be described with reference to the flowchart in Fig. 9. Note that the program of the calculation unit 66 is executed, for example, when the wiper switch 16 is turned on. Alternatively, the program of the calculation unit 66 is executed, for example, when the wiper angle θw becomes a specific angle before the deceleration start angle θb.

[0058] Here, the time it takes for the number of pulses N(n-1) in the previous control cycle τ(n-1) to reach the number of pulses N(n) in the current control cycle τ(n) corresponds to the ripple cycle T.

[0059] Therefore, in step S300, the calculation unit 66 obtains the time related to the number of pulses N(n) in the current control cycle τ(n) and the number of pulses N(n-1) in the previous control cycle τ(n-1) from the estimation unit 64 as information for calculating the ripple cycle T.

[0060] Subsequently, in step S302, the calculation unit 66 calculates the ripple period T from the time acquired in step S300.

[0061] Subsequently, in step S304, the calculation unit 66 calculates the deceleration start angle θb and the deceleration control time Tb based on the ripple period T calculated in step S302 and the map.

[0062] Here, when the ripple period T is short, the wiper 90 and the wiper motor 100 rotate at high speed. Therefore, at this time, in order to prevent the wiper 90 from overrunning, it is necessary to decelerate the wiper 90 early. Furthermore, when the ripple period T is long, the wiper 90 and the wiper motor 100 rotate at low speed. Therefore, at this time, it is not necessary to decelerate the wiper 90 early.

[0063] Therefore, as shown in Figure 10, the map for calculating the deceleration start angle θb is set so that the deceleration start angle θb decreases as the ripple period T shortens in the range from 0 to θmax and in the range from θmax to 2 x θmax.

[0064] Furthermore, when the wiper 90 and the wiper motor 100 are rotating at high speed, a longer deceleration control time Tb makes it easier to decelerate the wiper 90 and the wiper motor 100. Furthermore, when the wiper 90 and the wiper motor 100 are rotating at low speed, the deceleration control time Tb may be short.

[0065] Therefore, the map for calculating the deceleration control time Tb is set so that the deceleration control time Tb becomes longer as the ripple period T becomes shorter, for example, as shown in FIG.

[0066] Then, the calculation unit 66 outputs a signal corresponding to the calculated deceleration start angle θb and deceleration control time Tb to the drive unit 62. Thereafter, the processing of the calculation unit 66 returns to step S300. At this time, if the program of the calculation unit 66 is executed because the wiper angle θw has become a specific angle before the deceleration start angle θb, the processing of the calculation unit 66 may end.

[0067] As described above, the calculation unit 66 estimates the ripple period T, the deceleration start angle θb, and the deceleration control time Tb. Next, it will be described how the wiper control device 30 estimates the wiper angle θw with a simple configuration and suppresses overrun of the wiper 90.

[0068] The wiper device control method described in Patent Document 1 requires a Hall IC for detecting the position of an electric motor to detect the speed of the wiper arm. This requires wiring for the Hall IC for detecting the position of the electric motor, which complicates the configuration of the wiper device described in Patent Document 1. Furthermore, if the wiper arm moves at a speed due to inertia at the upper or lower reversal position, overrun may occur, passing the upper or lower reversal position targeted by the design. Overrun may cause, for example, interference between the wiper blade connected to the wiper arm and the A-pillar of the vehicle. Furthermore, for example, if the wiper blade is mechanically reversed before the reversal position in anticipation of overrun, the wiper blade may leave some of the water or other debris on the windshield, obstructing the driver's visibility. Therefore, there is a need to suppress this overrun.

[0069] In contrast, the wiper control device 30 of this embodiment includes a Hi switch 35, a Lo switch 45, a drive unit 62, an estimation unit 64, and a calculation unit 66. The Hi switch 35 and the Lo switch 45 correspond to elements that rotate the wiper motor 100. The wiper motor 100 drives the wiper 90. The wiper 90 reciprocates between a lower reversal position Pd and an upper reversal position Pu. The lower reversal position Pd corresponds to the first position. The upper reversal position Pu corresponds to the second position.

[0070] The drive unit 62 controls the on / off of the Hi switch 35 and the Lo switch 45. In step S200, the estimation unit 64 serves as an acquisition unit that acquires a value related to the current flowing through the wiper motor 100. In step S210, the estimation unit 64 estimates the wiper angle θw based on a current ripple Ir, which is part of the current flowing through the wiper motor 100 and has a periodicity corresponding to the operation of the wiper motor 100. In step S304, the calculation unit 66 calculates the deceleration start angle θb based on the ripple period T.

[0071] Furthermore, when the Hi switch 35 or the Lo switch 45 is on and the wiper angle θw becomes the deceleration start angle θb, the drive unit 62 turns off the on Hi switch 35 or the Lo switch 45. As a result, the drive unit 62 stops the power supply from the Hi switch 35 or the Lo switch 45 to the wiper motor 100, thereby decelerating the wiper 90.

[0072] Furthermore, after the wiper angle θw reaches the deceleration start angle θb, the wiper position Pw is assumed to be at the lower reversal position Pd, a position earlier than the lower reversal position Pd, or the upper reversal position Pu or a position earlier than the upper reversal position Pu. At this time, the drive unit 62 turns on the Hi switch 35 or the Lo switch 45 that was previously turned off. This causes the drive unit 62 to resume power supply from the Hi switch 35 or the Lo switch 45 to the wiper motor 100.

[0073] As a result, the wiper angle θw is estimated without providing a Hall IC for detecting the position of the electric motor. This eliminates the need to provide wiring for a Hall IC for detecting the position of the electric motor. Therefore, the wiper angle θw is estimated with a simple configuration. Also, here, a cam switch that turns on and off in response to the rotation of the wiper motor 100 may be used to determine whether the wiper position Pw is at or near the lower reversal position Pd. 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 be provided with a cam switch.

[0074] In addition, the wiper 90 is decelerated immediately before the lower reversal position Pd or the upper reversal position Pu, so that the wiper 90 smoothly reverses at the lower reversal position Pd or the upper reversal position Pu. This prevents the wiper 90 from overrunning. Furthermore, the operating noise of the wiper 90 generated when the wiper position Pw is the lower reversal position Pd or the upper reversal position Pu is reduced.

[0075] Furthermore, the first embodiment also provides the following effects.

[0076] [1] After the deceleration control time Tb has elapsed since the wiper angle θw reached the deceleration start angle θb, the drive unit 62 turns on the Hi switch 35 or the Lo switch 45, which had been turned off. As a result, the drive unit 62 resumes the supply of power from the Hi switch 35 or the Lo switch 45 to the wiper motor 100.

[0077] This adjusts the deceleration of the wiper 90, making it easier for the wiper 90 to move smoothly to the lower reversing position Pd or the upper reversing position Pu. As a result, overrunning of the wiper 90 is suppressed.

[0078] [2] The wiper motor 100 has a Hi terminal 104 and a Lo terminal 106. When the Hi switch 35 is turned on, a current flows to the wiper motor 100 via the Hi terminal 104, thereby rotating the wiper motor 100. When the Lo switch 45 is turned on, a current flows to the wiper motor 100 via the Lo terminal 106, thereby rotating the wiper motor 100.

[0079] Here, when the Hi switch 35 is on and the Lo switch 45 is off, i.e., when the wiper 90 is in the continuous high-speed mode, the wiper angle θw becomes the deceleration start angle θb. At this time, in the first embodiment, the drive unit 62 changes the Hi switch 35 from on to off, thereby stopping the supply of power from the Hi switch 35 to the wiper motor 100. The drive unit 62 also changes the Lo switch 45 from off to on, thereby causing the supply of power from the Lo switch 45 to the wiper motor 100, thereby decelerating the wiper 90.

[0080] Furthermore, after the wiper angle θw reaches the deceleration start angle θb, the wiper position Pw is assumed to be at the lower reversal position Pd, a position earlier than the lower reversal position Pd, or the upper reversal position Pu or a position earlier than the upper reversal position Pu. At this time, the drive unit 62 restarts the power supply from the Hi switch 35 to the wiper motor 100 by changing the Hi switch 35 from off to on. The drive unit 62 also stops the power supply from the Lo switch 45 to the wiper motor 100 by changing the Lo switch 45 from on to off. In this case, the Hi terminal 104 corresponds to the first terminal. The Lo terminal 106 corresponds to the second terminal. The Hi switch 35 corresponds to the first element. The Lo switch 45 corresponds to the second element.

[0081] Also, assume that when the Hi switch 35 is off and the Lo switch 45 is on, i.e., when the wiper 90 is in the continuous low speed mode, the wiper angle θw becomes the deceleration start angle θb. At this time, the drive unit 62 turns the Lo switch 45 from on to off to stop the power supply from the Hi switch 35 to the wiper motor 100, and keeps the Hi switch 35 off to decelerate the wiper 90.

[0082] Furthermore, after the wiper angle θw reaches the deceleration start angle θb, the wiper position Pw is assumed to be at the lower reversal position Pd, a position before the lower reversal position Pd, or the upper reversal position Pu or a position before the upper reversal position Pu. At this time, the drive unit 62 switches the Lo switch 45 from OFF to ON, thereby restarting the power supply from the Lo switch 45 to the wiper motor 100 and keeping the Hi switch 35 OFF. In this case, the Hi switch 35 corresponds to the first element and the Lo switch 45 corresponds to the second element. Alternatively, the Lo switch 45 corresponds to the first element and the Hi switch 35 corresponds to the second element.

[0083] As described above, these processes decelerate the wiper 90 immediately before the lower reversal position Pd or the upper reversal position Pu, allowing the wiper 90 to smoothly reverse at the lower reversal position Pd or the upper reversal position Pu. This prevents the wiper 90 from overrunning. Furthermore, 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.

[0084] (Second embodiment) The second embodiment differs from the first embodiment in the deceleration control by the drive unit 62. Other than this, the second embodiment is similar to the first embodiment.

[0085] In the first embodiment, in step S108, when the wiper angle θw is the deceleration start angle θb while the wiper 90 is in the continuous high speed mode, the drive unit 62 switches the Lo switch 45 from off to on.

[0086] In contrast, in the second embodiment, in step S108, when the operating state of the wiper 90 is in continuous high-speed mode and the wiper angle θw is the deceleration start angle θb, the drive unit 62 does not turn on the Lo switch 45 but keeps it off, as shown in Figure 12.

[0087] In this way, in the second embodiment, deceleration control is performed by the drive unit 62. In the second embodiment, the same effects as in the first embodiment are achieved.

[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 driver, acquirer, estimator, and calculator, and the methods 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 driver, acquirer, estimator, and calculator, and the methods 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 driver, acquirer, estimator, and calculator, and the methods 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] In each of the above embodiments, the Hi switch 35, Hi current detection unit 39, Lo switch 45, and Lo current detection unit 49 are each separate. However, the Hi switch 35 and the Hi current detection unit 39 may be integrated. Furthermore, the Lo switch 45 and the Lo current detection unit 49 may be integrated. Furthermore, the Hi switch 35, Hi current detection unit 39, Lo switch 45, and Lo current detection unit 49 may be integrated.

[0091] In each of the above embodiments, the wiper motor 100 may be either a DC motor or an AC motor. Furthermore, if the wiper motor 100 is a DC motor, it is preferably a permanent magnet field DC commutator motor. In this case, for example, the wiper motor 100 is a multi-speed motor as disclosed in Japanese Patent Application Laid-Open No. 10-503640. This multi-speed motor is a motor that can switch between low and high speeds by selectively switching between low-speed brushes and high-speed brushes to change the current supply circuit to the armature. Specifically, at least one pair of permanent magnets is fixed to the inner surface of a motor yoke (not shown), a winding is attached to the core of the armature, for example, by lap winding, and a Hi terminal 104, a Lo terminal 106, and a GND terminal 108, which serve as brushes, are arranged on the commutator so as to be in sliding contact with the commutator. Furthermore, the Hi terminal 104 is arranged at a position advanced from the Lo terminal 106. As a result, 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 when the Lo terminal 106 is selected.

[0092] In each of the above embodiments, the estimation unit 64 may output a signal corresponding to the wiper angle θw estimated in step S210 to an external device. For example, the external device is a washer unit 70, as shown in FIG. 13 . The washer unit 70 controls the timing of spraying washer fluid to wash the windshield (not shown) based on the signal from the estimation unit 64. For example, the washer unit 70 sprays washer fluid when the wiper angle θw estimated by the estimation unit 64 is zero or 2×θmax, i.e., when the wiper position Pw is at the lower reversal position Pd. Furthermore, for example, the washer unit 70 sprays washer fluid when the wiper angle θw estimated by the estimation unit 64 is θmax, i.e., when the wiper position Pw is at the upper reversal position Pu.

[0093] In each of the above embodiments, the estimation unit 64 calculates the number of times when the change amount ΔIm is equal to or greater than the change threshold ΔIm_th as the number of pulses N. However, the number of pulses N is not limited to the number of times when the change amount ΔIm is equal to or greater than the change threshold ΔIm_th. For example, as shown in FIG. 14 , the estimation unit 64 may calculate the number of times when the current flowing through the wiper motor 100 changes from less than the current threshold Im_th to equal to or greater than the current threshold Im_th as the number of pulses N. Alternatively, the estimation unit 64 may calculate the number of times when the current flowing through the wiper motor 100 changes from greater than the current threshold Im_th to equal to or less than the current threshold Im_th as the number of pulses N. Note that the current threshold Im_th is calculated, for example, based on the voltage applied to the wiper motor 100, similar to the change threshold ΔIm_th.

[0094] In each of the above embodiments, the map for calculating the deceleration control time Tb is set so that the deceleration control time Tb becomes longer as the ripple period T becomes shorter. In contrast to this, the map for calculating the deceleration control time Tb may be set so that the deceleration control time Tb becomes shorter as the ripple period T becomes shorter, as shown in Fig. 15 .

[0095] (Aspects of the present disclosure) As is clear from the above description of the embodiments, the disclosure of this specification includes at least the following aspects.

[0096] [Point 1] A wiper control device, an element (35, 45) that, when turned on, passes a current through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu), thereby rotating the wiper motor; A driving unit (62) that controls the on / off of the element; an acquisition unit (S200) for acquiring values ​​relating to the current (Im_Hi, Im_Lo) flowing through the wiper motor; an estimation unit (S210) that estimates a wiper angle (θw) that is a rotation angle of the wiper based on a current ripple (Ir) having a periodicity corresponding to the drive of the wiper motor among currents flowing through the wiper motor; a calculation unit (66) that calculates a deceleration start angle (θb) that is the wiper angle before the wiper reaches the first position and the second position and at which the wiper starts to decelerate, based on a ripple period (T) that is the period of the current ripple; and Equipped with The drive unit is When the element is on, when the wiper angle reaches the deceleration start angle, the element is turned off to stop the power supply from the element to the wiper motor, thereby decelerating the wiper; When the wiper position is the first position, a position earlier than the first position, the second position, or a position earlier than the second position after the wiper angle has reached the deceleration start angle, the wiper control device resumes power supply from the element to the wiper motor by switching the element from off to on. [Point 2] the calculation unit calculates a deceleration control time (Tb) based on the ripple period, the deceleration control time being the time from when the wiper angle reaches the deceleration start angle to when the element is switched from off to on; The wiper control device described in Aspect 1, wherein the drive unit resumes power supply to the wiper motor by switching the element from off to on after the deceleration control time has elapsed since the wiper angle reached the deceleration start angle. [Point 3] The wiper motor is a first terminal (104) to which power is supplied; a second terminal (106) to which a power smaller than that supplied to the first terminal is supplied; and The element is a first element (35), When the first element is turned on, a current flows through the wiper motor via the first terminal, thereby rotating the wiper motor. the wiper control device includes a second element (45) that, when turned on, causes a current to flow through the wiper motor via the second terminal, thereby rotating the wiper motor; The drive unit is Controlling the on / off of the first element and the second element; When the first element is on and the second element is off, when the wiper angle reaches the deceleration start angle, By switching the first element from on to off, the supply of power from the first element to the wiper motor is stopped; By turning on the second element from off, power is supplied from the second element to the wiper motor, thereby decelerating the wiper; After the wiper angle reaches the deceleration start angle, when the position of the wiper is at any one of the first position, a position earlier than the first position, the second position, and a position earlier than the second position, By switching the first element from off to on, power supply from the first element to the wiper motor is resumed; The wiper control device according to Aspect 1 or 2, wherein the second element is turned from on to off to stop the supply of power from the second element to the wiper motor. [Point 4] The wiper motor is a first terminal (104) to which power is supplied; a second terminal (106) to which a power smaller than that supplied to the first terminal is supplied; and The element is a first element (35), When the first element is turned on, a current flows through the wiper motor via the first terminal, thereby rotating the wiper motor. the wiper control device includes a second element (45) that, when turned on, causes a current to flow through the wiper motor via the second terminal, thereby rotating the wiper motor; The drive unit is Controlling the on / off of the first element and the second element; When the first element is on and the second element is off, when the wiper angle reaches the deceleration start angle, By switching the first element from on to off, the supply of power from the first element to the wiper motor is stopped, and by keeping the second element off, the wiper is decelerated; The wiper control device according to aspect 1 or 2, wherein, after the wiper angle reaches the deceleration start angle, when the wiper position is one of the first position, a position earlier than the first position, the second position, and a position earlier than the second position, the first element is turned from off to on, thereby resuming power supply from the first element to the wiper motor and keeping the second element off. [Point 5] The drive unit is When the second element is on and the first element is off, when the wiper angle reaches the deceleration start angle, By switching the second element from on to off, the supply of power from the second element to the wiper motor is stopped, and by keeping the first element off, the wiper is decelerated; A wiper control device according to aspect 3 or 4, wherein, after the wiper angle reaches the deceleration start angle, when the wiper position is one of the first position, a position earlier than the first position, the second position, and a position earlier than the second position, the second element is switched from off to on, thereby resuming power supply from the second element to the wiper motor and keeping the first element off. [Point 6] The wiper motor is a first terminal (104) to which power is supplied; a second terminal (106) to which a power smaller than that supplied to the first terminal is supplied; and The element is a first element (45), When the first element is turned on, a current flows through the wiper motor via the second terminal, thereby rotating the wiper motor. the wiper control device includes a second element (35) that, when turned on, causes a current to flow through the wiper motor via the first terminal, thereby rotating the wiper motor; The drive unit is Controlling the on / off of the first element and the second element; When the first element is on and the second element is off, when the wiper angle reaches the deceleration start angle, By switching the first element from on to off, the supply of power from the first element to the wiper motor is stopped, and by keeping the second element off, the wiper is decelerated; The wiper control device according to aspect 1 or 2, wherein, after the wiper angle reaches the deceleration start angle, when the wiper position is one of the first position, a position earlier than the first position, the second position, and a position earlier than the second position, the first element is turned from off to on, thereby resuming power supply from the first element to the wiper motor and keeping the second element off. [Point 7] The wiper control device according to any one of Aspects 1 to 6, wherein the estimation unit estimates the wiper angle based on the number of times (N) when the absolute value of the change (ΔIm) of the current flowing to the wiper motor is equal to or greater than a threshold (ΔIm_th). [Point 8] The wiper control device according to any one of Aspects 1 to 6, wherein the estimation unit estimates the wiper angle based on the number (N) of times when the current flowing to the wiper motor changes from less than a threshold (Im_th) to greater than or equal to the threshold. [Point 9] The wiper control device according to any one of aspects 1 to 6, wherein the estimation unit estimates the wiper angle based on the number (N) of times when the current flowing to the wiper motor changes from being greater than a threshold (Im_th) to being less than or equal to the threshold. [Point 10] The wiper control device according to any one of Aspects 7 to 9, wherein the calculation unit calculates the ripple period based on the number of times. [Explanation of symbols]

[0097] 14 Motor power supply 16 Wiper switch 35 Hi switch 39 Hi current detection section 45 Lo switch 49 Lo current detection section 62 Drive unit 64 Estimation part 66 Calculation Unit

Claims

1. A wiper control device, an element (35, 45) that, when turned on, causes a current to flow through a wiper motor (100) that drives a wiper (90) that reciprocates between a first position (Pd) and a second position (Pu), thereby rotating the wiper motor; A driving unit (62) that controls the on / off of the element; an acquisition unit (S200) for acquiring values ​​relating to currents (Im_Hi, Im_Lo) flowing through the wiper motor; an estimation unit (S210) that estimates a wiper angle (θw) that is a rotation angle of the wiper based on a current ripple (Ir) having a periodicity corresponding to the drive of the wiper motor among currents flowing through the wiper motor; a calculation unit (66) that calculates a deceleration start angle (θb) that is the wiper angle before the wiper reaches the first position and the second position and at which the wiper starts to decelerate, based on a ripple period (T) that is the period of the current ripple; and Equipped with The drive unit is When the element is on, when the wiper angle reaches the deceleration start angle, the element is turned off to stop the power supply from the element to the wiper motor, thereby decelerating the wiper; When the wiper position is one of the first position, a position earlier than the first position, the second position, and a position earlier than the second position after the wiper angle has reached the deceleration start angle, the wiper control device resumes power supply from the element to the wiper motor by switching the element from off to on.

2. the calculation unit calculates a deceleration control time (Tb) based on the ripple period, the deceleration control time being the time from when the wiper angle reaches the deceleration start angle to when the element is switched from off to on; 2. The wiper control device according to claim 1, wherein the drive unit resumes power supply to the wiper motor by switching the element from off to on after the deceleration control time has elapsed since the wiper angle reached the deceleration start angle.

3. The wiper motor is a first terminal (104) to which power is supplied; a second terminal (106) to which a power smaller than that supplied to the first terminal is supplied; and The element is a first element (35), When the first element is turned on, a current flows through the wiper motor via the first terminal, thereby rotating the wiper motor. the wiper control device includes a second element (45) that, when turned on, causes a current to flow through the wiper motor via the second terminal, thereby rotating the wiper motor; The drive unit is Controlling the on / off of the first element and the second element; When the first element is on and the second element is off, when the wiper angle reaches the deceleration start angle, By switching the first element from on to off, the supply of power from the first element to the wiper motor is stopped; By switching the second element from off to on, power is supplied from the second element to the wiper motor, thereby decelerating the wiper; After the wiper angle reaches the deceleration start angle, when the position of the wiper is at any one of the first position, a position earlier than the first position, the second position, and a position earlier than the second position, By switching the first element from off to on, power supply from the first element to the wiper motor is resumed; The wiper control device according to claim 1 , wherein the supply of power from the second element to the wiper motor is stopped by switching the second element from on to off.

4. The wiper motor is a first terminal (104) to which power is supplied; a second terminal (106) to which a power smaller than that supplied to the first terminal is supplied; and The element is a first element (35), When the first element is turned on, a current flows through the wiper motor via the first terminal, thereby rotating the wiper motor. the wiper control device includes a second element (45) that, when turned on, causes a current to flow through the wiper motor via the second terminal, thereby rotating the wiper motor; The drive unit is Controlling the on / off of the first element and the second element; When the first element is on and the second element is off, when the wiper angle reaches the deceleration start angle, By switching the first element from on to off, the supply of power from the first element to the wiper motor is stopped, and by keeping the second element off, the wiper is decelerated; 2. The wiper control device according to claim 1, wherein, after the wiper angle reaches the deceleration start angle, when the wiper position is one of the first position, a position earlier than the first position, the second position, and a position earlier than the second position, the first element is switched from off to on, thereby resuming power supply from the first element to the wiper motor and leaving the second element off.

5. The drive unit is When the second element is on and the first element is off, when the wiper angle reaches the deceleration start angle, By switching the second element from on to off, the supply of power from the second element to the wiper motor is stopped, and by keeping the first element off, the wiper is decelerated; 5. The wiper control device according to claim 3, wherein, after the wiper angle reaches the deceleration start angle, when the wiper position is one of the first position, a position earlier than the first position, the second position, and a position earlier than the second position, the second element is switched from off to on, thereby resuming power supply from the second element to the wiper motor and leaving the first element off.

6. The wiper motor is a first terminal (104) to which power is supplied; a second terminal (106) to which a power smaller than that supplied to the first terminal is supplied; and The element is a first element (45), When the first element is turned on, a current flows through the wiper motor via the second terminal, thereby rotating the wiper motor. the wiper control device includes a second element (35) that, when turned on, causes a current to flow through the wiper motor via the first terminal, thereby rotating the wiper motor; The drive unit is Controlling the on / off of the first element and the second element; When the first element is on and the second element is off, when the wiper angle reaches the deceleration start angle, By switching the first element from on to off, the supply of power from the first element to the wiper motor is stopped, and by keeping the second element off, the wiper is decelerated; 3. The wiper control device according to claim 1, wherein, after the wiper angle reaches the deceleration start angle, when the wiper position is one of the first position, a position earlier than the first position, the second position, and a position earlier than the second position, the first element is switched from off to on, thereby resuming power supply from the first element to the wiper motor and leaving the second element off.

7. The wiper control device according to claim 1 , wherein the estimation unit estimates the wiper angle based on the number (N) of times when an absolute value of a change (ΔIm) in the current flowing through the wiper motor is equal to or greater than a threshold (ΔIm_th).

8. The wiper control device according to claim 1 , wherein the estimation unit estimates the wiper angle based on the number (N) of times when the current flowing through the wiper motor changes from less than a threshold (Im_th) to equal to or greater than the threshold.

9. The wiper control device according to claim 1 , wherein the estimation unit estimates the wiper angle based on the number (N) of times that the current flowing through the wiper motor changes from being greater than a threshold (Im_th) to being equal to or less than the threshold.

10. The wiper control device according to claim 7 , wherein the calculation unit calculates the ripple period based on the number of times.

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