Wiper drive device, wiper drive method, and program

Abstract

To provide a wiper driving device, a wiper driving method and a program which can correctly set a movement range of a wiper even when washer liquid is jetted in a wiper having an overrun correction function.SOLUTION: A wiper driving device comprises: a wiper motor which drives a wiper; a load detection unit which detects a load applied on the wiper motor; and a control unit which determines whether overrun of the wiper occurs on the basis of a change in a detection value indicating the detected load, and sets a movement range for correction where the inversion position of the wiper is set according to whether jetting of the washer liquid is executed as a movement range of the wiper when determining that the overrun occurs.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wiper drive device, a wiper drive method, and a program. [Background technology]

[0002] When the wipers are operated while the vehicle is moving, the wind from the vehicle may cause the wipers to overrun outward from a preset reversing position (see, for example, Patent Document 1). For this reason, when overrun occurs during wiper drive control, a function is used to correct the reversing position of the wiper arm taking into account the wind from the vehicle (hereinafter also referred to as an "overrun correction function"). The overrun correction function detects the load torque of the wiper motor and determines whether or not an overrun will occur based on a change in the detected value of the load torque of the wiper motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-127179 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the load torque of the wiper motor can change not only when affected by wind but also when washer fluid is sprayed. Therefore, when washer fluid is sprayed, an overrun caused by wind is erroneously detected, and the overrun correction function is activated. As a result, the wiper arm movement range is not set correctly when washer fluid is sprayed, which can cause discomfort to the user.

[0005] The present invention has been made in consideration of the above circumstances, and its purpose is to provide a wiper drive device, a wiper drive method, and a program that are capable of correctly setting the wiper movement range even when washer fluid is sprayed in a wiper equipped with an overrun correction function. [Means for solving the problem]

[0006] A wiper drive device according to one aspect of the present invention includes a wiper motor that drives a wiper, a load detection unit that detects a load applied to the wiper motor, and a control unit that determines whether or not an overrun of the wiper will occur based on a change in a detection value indicating the detected load, and that, when it is determined that the overrun will occur, sets a correction movement range in which a reversal position of the wiper is set depending on whether spraying of washer fluid is performed, as a movement range of the wiper. The control unit sets a first correction movement range when the washer fluid injection is not performed, and sets a second correction movement range when the washer fluid injection is performed, the first correction movement range being narrower than the normal movement range that is set when it is determined that the overrun will not occur, and the second correction movement range being the same as the normal movement range, or a range narrower than the normal movement range but wider than the first correction movement range. .

[0007] A wiper driving method according to one aspect of the present invention includes: a load detection step in which a load detection unit detects a load applied to a wiper motor that drives a wiper; and a control step in which a control unit determines whether an overrun of the wiper will occur based on a change in a detection value indicating the detected load, and, when it is determined that the overrun will occur, sets a correction movement range in which a reversal position of the wiper is set depending on whether spraying of washer fluid is performed, as the movement range of the wiper. The control unit sets a first correction movement range when the washer fluid injection is not performed, and sets a second correction movement range when the washer fluid injection is performed, the first correction movement range being narrower than a normal movement range that is set when it is determined that the overrun will not occur, and the second correction movement range being the same as the normal movement range, or a range that is narrower than the normal movement range but wider than the first correction movement range. .

[0008] A program according to one aspect of the present invention causes a computer to function as: load detection means for detecting a load applied to a wiper motor that drives a wiper; and control means for determining whether or not an overrun of the wiper will occur based on a change in a detection value indicating the detected load, and for setting, when it is determined that the overrun will occur, a correction movement range in which a reversal position of the wiper is set depending on whether spraying of washer fluid is performed, as the movement range of the wiper. The control means sets a first correction movement range when the washer fluid injection is not performed, and sets a second correction movement range when the washer fluid injection is performed, the first correction movement range being narrower than the normal movement range that is set when it is determined that the overrun will not occur, and the second correction movement range being the same as the normal movement range, or a range narrower than the normal movement range but wider than the first correction movement range. . [Effects of the Invention]

[0009] As described above, according to the present invention, in a wiper equipped with an overrun correction function, it is possible to correctly set the movement range of the wiper arm even when washer fluid is sprayed. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a schematic configuration of a wiper drive device according to an embodiment of the present invention; [Figure 2] 5A and 5B are diagrams illustrating an example of an overrun correction function in the wiper drive device according to the embodiment. [Figure 3] 5 is a diagram showing an example of the relationship between overrun and spray of washer fluid in the wiper drive device 1 according to the present embodiment. FIG. [Figure 4] 5 is a flowchart showing an example of a processing flow in the wiper drive device according to the present embodiment. [Figure 5] FIG. 4 is a diagram showing an example of time-series changes in waveforms relating to the operation of the wiper drive device according to the embodiment. [Figure 6] FIG. 4 is a diagram showing an example of time-series changes in waveforms relating to the operation of the wiper drive device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Generally, two wipers, one on the left and one on the right, are provided on the front of a vehicle, but in the embodiment described below, for the sake of convenience, only the wiper on one side will be described.

[0012] <1. Outline of the wiper drive unit> The schematic configuration of the wiper drive device according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the schematic configuration of the wiper drive device according to this embodiment. As shown in FIG. 1, the wiper drive device 1 includes a wiper 20, a wiper motor 30, a wiper drive unit 31, a control unit 32, a load detection unit 33, a wiper switch 41, a washer switch 42, a washer pump 50, a washer tank 51, and a washer drive unit 53.

[0013] 1 includes a wiper arm 21 and a wiper blade 22. A wiper rubber (not shown) is attached to the wiper blade 22.

[0014] The wiper motor 30 is a motor that drives the wipers 20. A drive signal is supplied to the wiper motor 30 from a control unit 32 via a wiper drive unit 31, and this drive signal causes the wiper motor 30 to rotate. When the wiper motor 30 rotates, the wiper arm 21 rotates in accordance with this rotation, and the wiper blade 22 moves back and forth on the windshield 10. The load detection unit 33 detects the load applied to the wiper motor 30. Specifically, the load detection unit 33 detects the load torque applied to the wiper motor 30. A detection value indicating the load torque detected by the load detection unit 33 is supplied from the load detection unit 33 to the control unit 32.

[0015] The washer pump 50 sprays washer fluid 52 onto the windshield 10. The washer fluid 52 is stored in a washer tank 51. A washer signal is supplied to the washer pump 50 from the control unit 32 via a washer drive unit 53, and the washer pump 50 is driven by this washer signal. When the washer pump 50 is driven, the washer fluid 52 in the washer tank 51 is supplied to a washer nozzle (not shown) via a washer tube (not shown) connected to the washer tank 51, and is sprayed onto the windshield 10 from the washer nozzle (not shown).

[0016] The control unit 32 has a function of controlling the overall operation of the wiper drive device 1. The function of the control unit 32 is realized, for example, by causing a CPU (Central Processing Unit) provided as hardware in the wiper drive device 1 to execute a program. In this embodiment, the control unit 32 has a determination function and an overrun correction function. The control unit 32 uses the determination function to determine whether or not an overrun of the wiper 20 will occur based on a change in the detected value of the load torque applied to the wiper motor 30. Furthermore, when the control unit 32 determines using the overrun correction function that an overrun of the wiper 20 will occur, the control unit 32 sets a correction movement range as the movement range of the wiper 20, which range is determined based on whether or not spraying of the washer fluid 52 has been performed.

[0017] The correction movement range is a movement range of the wiper 20 in which the reversal position of the wiper 20 is set depending on whether or not the spray of the washer fluid 52 has been performed. The correction movement range includes a traveling wind correction movement range (first correction movement range) and a washer correction movement range (second correction movement range). The traveling wind correction movement range is a correction movement range that is set when it is determined that an overrun will occur but the spray of the washer fluid 52 has not been performed. The washer correction movement range is a correction movement range that is set when it is determined that an overrun will occur and the spray of the washer fluid 52 has been performed. The travel range for road wind correction is narrower than the normal travel range (i.e., the travel range set during normal operation) that is set when it is determined that no overrun will occur, and the travel range for washer correction is narrower than the normal travel range but wider than the travel range for road wind correction. The lower inversion positions of the normal movement range, the traveling wind compensation movement range, and the washer compensation movement range are assumed to be the same. Therefore, the upper inversion positions of the normal movement range are closest to the pillar 12, followed by the washer compensation movement range and the traveling wind compensation movement range, which are further from the pillar 12 in that order.

[0018] A wiper switch 41 and a washer switch 42 are connected to the control unit 32. The wiper switch 41 is a switch for controlling the drive of the wiper 20. The washer switch 42 is a switch for controlling the spray of washer fluid 52. A signal from the wiper switch 41 or the washer switch 42 is supplied to the control unit 32. When the wiper switch 41 is turned on, a drive signal is output from the control unit 32 to the wiper drive unit 31. This causes the wiper motor 30 to rotate and drive the wiper 20, causing the wiper arm 21 to reciprocate, and raindrops on the windshield 10 to be wiped away by the wiper blade 22 in accordance with this reciprocating motion.

[0019] When the washer switch 42 is turned on, a washer signal is output from the control unit 32 to the washer driving unit 53. This drives the washer pump 50, and the washer fluid 52 in the washer tank 51 is supplied to a washer nozzle (not shown) via a washer tube (not shown) connected to the washer tank 51, and is sprayed onto the windshield 10 from the washer nozzle (not shown).

[0020] <2. Overrun correction function> The schematic configuration of the wiper drive device 1 according to this embodiment has been described above. Next, the overrun correction function according to this embodiment will be described with reference to Figs.

[0021] FIG. 2 is a diagram showing an example of the overrun correction function in the wiper drive device 1 according to this embodiment. 2 is rotated, the wiper arm 21 reciprocates (i.e., within a range of movement) between a lower reversal position (hereinafter also referred to as the "lower reversal position") and an upper reversal position (hereinafter also referred to as the "upper reversal position") on the windshield 10. In the following description, the path along which the wiper arm 21 moves from the lower reversal position to the upper reversal position, as indicated by arrow A1, is referred to as the outward path, and the path along which the wiper arm 21 moves from the upper reversal position to the lower reversal position, as indicated by arrow A2, is referred to as the return path. In this embodiment, the normal movement range is set such that the position at angle L0 is the lower reversal position and the position at angle L1 is the upper reversal position. In this case, the wiper arm 21 reciprocates within the range from angle L0, which is the lower reversal position, to angle L1, which is the upper reversal position.

[0022] When the wiper 20 is operated while the vehicle is moving, the wiper blade 22 may be subjected to wind from the vehicle as indicated by arrow F in FIG. 2. When the wiper blade 22 is subjected to wind from the vehicle, it receives a force that moves it closer to the pillar 12. As a result, the range of movement of the wiper arm 21 becomes larger than the normal range of movement. For example, the range of movement of the wiper arm 21 is from angle L0 to angle L2. In this case, the wiper blade 22 overruns toward the pillar 12 by the difference between angle L1 and angle L2. The overrun correction function is a function for correcting such overrun of the wiper blade 22 caused by wind while traveling.

[0023] The overrun correction function determines whether or not an overrun due to traveling wind will occur based on the difference between the load on the wiper motor 30 detected when the wiper arm 21 moves on the outward path and the load on the wiper motor 30 detected when the wiper arm 21 moves on the return path. If this difference is equal to or greater than a predetermined threshold, it is determined that an overrun due to traveling wind will occur, and a traveling wind correction movement range is set as the movement range of the wiper arm 21.

[0024] That is, when the wiper blade 22 is not affected by the wind while the vehicle is traveling, the load torque of the wiper motor 30 is substantially the same on the forward and backward directions.

[0025] In contrast, when the wiper blade 22 is affected by wind due to traveling, the difference in load torque of the wiper motor 30 between the forward and backward directions increases. Specifically, when the wiper arm 21 is moving in the forward direction as shown by arrow A1, the force of the wind due to traveling is added to the driving force of the wiper motor 30, so the load torque applied to the wiper motor 30 decreases. On the other hand, when the wiper arm 21 is moving in the backward direction as shown by arrow A2, the wind due to traveling acts as a force that resists the driving force of the wiper motor 30, so the load torque applied to the wiper motor 30 increases.

[0026] For this reason, in the overrun correction function, the control unit 32 acquires a detected value of the load torque applied to the wiper motor 30 from the load detection unit 33, calculates the difference in the load torque applied to the wiper motor 30 on the forward and backward directions, and determines whether an overrun will occur based on the result of comparing this difference with a threshold. If this difference is less than the threshold, the control unit 32 determines that an overrun will not occur and leaves the movement range of the wiper arm 21 as the normal movement range. That is, in this example, during normal times when no overrun will occur, the movement range of the wiper arm 21 is set to a range from angle L0 to angle L1. On the other hand, when the difference in load torque applied to the wiper motor 30 between the forward and backward directions exceeds a threshold, the control unit 32 determines that an overrun will occur and sets a travel range for wind compensation as the travel range of the wiper arm 21. The travel range for wind compensation is, for example, a range from angle L0 to angle L3, which is narrower than the normal travel range (angle L0 to angle L1). When wind is generated, the wiper blade 22 receives a force that moves it closer to the pillar 12. For this reason, the travel range for wind compensation is set to a range obtained by subtracting the travel range (angle) added by wind from the normal travel range. As a result, if the wiper arm 21 travel range is set to angle L0 to angle L3 and the wiper motor 30 is operated while being affected by wind, the wiper arm 21 will move within the range from angle L0 to angle L1. Therefore, the control unit 32 can perform control so that an overrun does not occur.

[0027] (Relationship between overrun and washer) Here, a description will be given of the relationship between overrun and spray of washer fluid in the wiper drive device 1 according to this embodiment. Fig. 3 is a diagram showing an example of the relationship between overrun and spray of washer fluid in the wiper drive device 1 according to this embodiment. The washer fluid 52 may be sprayed only on the forward or backward path, or may be sprayed on both the forward and backward paths. In this embodiment, the washer fluid 52 is sprayed so as to be wiped away by the wiper blade 22 while the wiper arm 21 moves from the lower reversing position to the upper reversing position on the forward path.

[0028] 3, when the wiper arm 21 is moved in the forward direction as indicated by the arrow A1, the washer fluid 52 is sprayed from the washer pump 50. As a result, the frictional force between the wiper rubber of the wiper blade 22 and the windshield 10 is reduced by the washer fluid 52, and the load torque applied to the wiper motor 30 is reduced.

[0029] In contrast, when the wiper arm 21 is moved in the backward direction as indicated by arrow A2, the washer fluid 52 on the windshield 10 dries, increasing the frictional force between the wiper rubber of the wiper blade 22 and the windshield 10. This increases the load torque applied to the wiper motor 30.

[0030] Thus, when washer fluid 52 is sprayed, the difference in load torque on wiper motor 30 increases between when wiper arm 21 is moved in the forward direction and when it is moved in the backward direction, just as when the wiper arm is affected by wind. As a result, when washer fluid 52 is sprayed, the overrun correction function is activated, and the movement range of wiper arm 21 is set to the movement range for wind compensation (angles L0 to L3). This may result in the movement range of wiper arm 21 being narrower than the normal movement range (angles L0 to L1) even when the wiper arm is not affected by wind.

[0031] Therefore, in the wiper drive device 1 according to the embodiment of the present invention, the movement range of the wiper arm 21 due to the overrun correction function is set to be different between when the washer fluid 52 is being sprayed and when the washer fluid 52 is not being sprayed. For example, when the washer fluid 52 is not being sprayed, a movement range for road wind correction is set, and when the washer fluid 52 is being sprayed, a movement range for road wind correction that is wider than the movement range for road wind correction is set. As a result, even if overrun correction is performed due to the spraying of washer fluid 52, the wiper arm 21 moves closer to the pillar 12 than when overrun correction is performed due to the wind from traveling. This reduces the sense of discomfort felt by the user by overrun correction.

[0032] <3. Processing flow> The overrun correction function according to this embodiment has been described above. Next, the flow of processing in the wiper drive device 1 according to this embodiment will be described with reference to Fig. 4 to Fig. 6. Fig. 4 is a flowchart showing an example of the flow of processing in the wiper drive device 1 according to this embodiment.

[0033] As shown in FIG. 4, the control unit 32 acquires a detection value of the load torque applied to the wiper motor 30 from the load detection unit 33 (step S1).

[0034] Next, the control unit 32 determines whether the difference between the load torque applied to the wiper motor 30 when the wiper arm 21 is moved on the forward side and the load torque applied to the wiper motor 30 when the wiper arm 21 is moved on the return side is greater than or equal to a threshold value (step S2). If the difference in load torque applied to the wiper motor 30 between the forward and backward directions is equal to or greater than the threshold value (step S2 / YES), the control unit 32 proceeds to step S3. On the other hand, if the difference in load torque is not equal to or greater than the threshold value (step S2 / No), the control unit 32 returns the process to step S1 and continues detecting the load torque of the wiper motor 30.

[0035] When the process proceeds to step S3, the control unit 32 determines whether or not a washer signal is being output (step S3). If the washer signal is not output (step S3 / NO), the control unit 32 proceeds to step S4. On the other hand, if the washer signal is output (step S3 / YES), the control unit 32 proceeds to step S5.

[0036] If the process proceeds to step S4, the control unit 32 sets the travel range for wind compensation as the travel range of the wiper arm 21 (step S4), and the process proceeds to step S6. Here, the travel range for wind compensation is the range in which angle L0 is the lower inverted position and angle L3 is the upper inverted position in Figures 2 and 3, and is narrower than the normal travel range in which angle L0 is the lower inverted position and angle L1 is the upper inverted position.

[0037] If the process proceeds to step S5, the control unit 32 sets the washer correction movement range as the movement range of the wiper arm 21 (step S5), and the process proceeds to step S6. Here, the washer correction movement range is a range in which angle L0 in Figures 2 and 3 is the lower reversal position and any position between angle L3 and angle L1 is the upper reversal position, and is a range narrower than the normal movement range but wider than the running wind correction movement range.

[0038] When the process proceeds to step S6, the control unit 32 drives the wiper motor 30 so that the wiper arm 21 moves within the movement range set in step S4 or step S5 (step S6).

[0039] Here, time series changes in waveforms relating to the operation of the wiper drive device 1 according to this embodiment will be described with reference to Fig. 5 and Fig. 6. Fig. 5 and Fig. 6 are diagrams showing an example of time series changes in waveforms relating to the operation of the wiper drive device 1 according to this embodiment. Fig. 5 and Fig. 6 show a waveform showing time series changes in the position (angle) of the wiper arm 21, a waveform showing time series changes in the level of the washer signal, a waveform showing time series changes in the level of the correction signal, and a waveform showing time series changes in the load torque applied to the wiper motor 30.

[0040] 5 shows the time series changes of each waveform when the washer fluid 52 is not being sprayed, and therefore the waveform of the washer signal is maintained at a low level. 5, before time T1, there is no influence of wind while the wiper arm 21 is traveling, and the load torque applied to the wiper motor 30 is almost the same on the forward and backward directions. At this time, the difference in the load torque applied to the wiper motor 30 on the forward and backward directions is less than the threshold value, so the correction signal is at a low level. While the correction signal is at a low level, the wiper arm 21 is set to move within the normal movement range (from angle L0 to angle L1).

[0041] After time T1, the load torque applied to the wiper motor 30 decreases on the forward path and increases on the backward path due to the influence of the wind generated by the vehicle. As a result, the difference in the load torque applied to the wiper motor 30 between the forward path and the backward path exceeds a threshold value. In this case, the control unit 32 determines that an overrun will occur due to the influence of the wind, and the correction signal goes high at time T2. When the correction signal goes high, the movement range of the wiper arm 21 is set to the movement range for wind correction (angle L0 to angle L3).

[0042] FIG. 6 shows the time series changes of each waveform when the washer fluid 52 is injected. 6, before time T10, spraying of washer fluid 52 is not performed, and the load torque applied to wiper motor 30 is almost the same on the forward and backward directions. At this time, the difference in the load torque applied to wiper motor 30 on the forward and backward directions is less than the threshold value, so the correction signal is at a low level. While the correction signal is at a low level, wiper arm 21 is set to move within the normal movement range (angle L0 to angle L1).

[0043] Assume that at time T10, the user turns on the washer switch 42 to spray the washer fluid 52. As a result, the washer signal goes high at time T10. When the washer signal goes high, the washer fluid 52 is sprayed from the washer pump 50 on the forward path of the wiper blade 22. As a result, the load torque applied to the wiper motor 30 on the forward path decreases, and the difference in the load torque applied to the wiper motor 30 on the forward path and the backward path becomes equal to or greater than a threshold value.

[0044] When the difference in load torque applied to the wiper motor 30 between the forward and backward directions becomes equal to or greater than a threshold, the correction signal goes high at time T11. If the washer signal is high at this time, the movement range of the wiper arm 21 is set to the washer correction movement range (angle L0 to angle L1). As a result, when the washer fluid 52 is sprayed to drive the wiper, even if the overrun correction function is activated, the movement range of the wiper arm 21 can be set to the normal movement range (angle L0 to angle L1), reducing the sense of discomfort felt by the user.

[0045] As described above, in the wiper drive device 1 according to this embodiment, when the wiper drive device 1 is affected by wind while traveling, a movement range that takes into account the influence of wind (traveling wind correction movement range) is set as the movement range of the wiper arm 21. As a result, the wiper drive device 1 can correct overrun of the wiper blade 22 when the difference in load torque applied to the wiper motor 30 between the forward and backward directions due to the influence of wind becomes equal to or greater than a threshold value. Furthermore, in the wiper drive device 1 according to this embodiment, when the washer fluid 52 is sprayed, a movement range (washer correction movement range) that takes into account the spraying of the washer fluid 52 is set as the movement range of the wiper arm 21. As a result, even if the difference in load torque applied to the wiper motor 30 between the forward and backward directions due to the spraying of the washer fluid 52 exceeds a threshold value, the wiper drive device 1 can bring the movement range of the wiper arm 21 closer to the normal movement range. Therefore, the wiper drive device 1 according to this embodiment makes it possible to correctly set the movement range of the wiper even when washer fluid is sprayed in a wiper equipped with an overrun correction function, thereby reducing the discomfort felt by the user when the wiper is driven while washer fluid is being sprayed.

[0046] Furthermore, the wiper drive device 1 according to this embodiment can reduce the number of wiper operations caused by erroneous detection and reduce the sense of discomfort experienced by the user, thereby contributing to providing access to a sustainable transportation system by improving traffic safety. This can contribute to achieving Goal 11 of the Sustainable Development Goals (SDGs) set by the United Nations, "Make cities and human settlements inclusive, safe, resilient and sustainable."

[0047] The above describes an embodiment of the present invention. Note that all or part of the wiper drive device 1 in the above-described embodiment may be implemented by a computer. In this case, a program for implementing the functions may be recorded on a computer-readable recording medium, and the program may be loaded into a computer system and executed. Note that the term "computer system" as used herein includes hardware such as an OS and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, as well as storage devices such as hard disks built into a computer system. Furthermore, the term "computer-readable recording medium" may also include devices that dynamically store programs for a short period of time, such as communication lines used when transmitting programs via networks such as the Internet or telephone lines, or devices that store programs for a fixed period of time, such as volatile memory within a computer system serving as a server or client. The program may be for implementing part of the functions described above, or may be capable of implementing the functions in combination with a program already stored in the computer system, or may be implemented using a programmable logic device such as an FPGA (Field Programmable Gate Array).

[0048] Although an embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes designs within the scope of the gist of the present invention. [Explanation of symbols]

[0049] 1...Wiper drive device, 20...Wiper, 21...Wiper arm, 22...Wiper blade, 30...Wiper motor, 31...Wiper drive unit, 32...Control unit, 33...Load detection unit, 41...Wiper switch, 42...Washer switch, 50...Washer pump, 51...Washer tank, 52...Washer fluid, 53...Washer drive unit

Claims

1. a wiper motor for driving the wiper; a load detection unit that detects a load applied to the wiper motor; a control unit that determines whether or not an overrun of the wiper will occur based on a change in a detection value indicating the detected load, and when it is determined that the overrun will occur, sets a correction movement range in which a reversal position of the wiper is set depending on whether spraying of washer fluid has been performed as the movement range of the wiper; Equipped with The control unit sets a first correction movement range when the washer fluid is not injected, and sets a second correction movement range when the washer fluid is injected, the first correction movement range is a range narrower than a normal movement range that is set when it is determined that the overrun will not occur, the second correction movement range is the same as the normal movement range, or is narrower than the normal movement range but wider than the first correction movement range; Wiper drive unit.

2. The control unit determines that the overrun has occurred when a difference between a load on the wiper motor detected when the wiper moves from a lower reversal position to an upper reversal position and a load on the wiper motor detected when the wiper moves from an upper reversal position to a lower reversal position is equal to or greater than a predetermined threshold. The wiper drive device according to claim 1.

3. The washer fluid is sprayed so as to be wiped away while the wiper moves from the lower inverted position to the upper inverted position. The wiper drive device according to any one of claims 1 and 2.

4. a load detection step in which a load detection unit detects a load applied to a wiper motor that drives the wiper; a control step in which a control unit determines whether or not an overrun of the wiper will occur based on a change in a detection value indicating the detected load, and when it determines that the overrun will occur, sets a correction movement range in which a reversal position of the wiper is set depending on whether spraying of washer fluid is performed as the movement range of the wiper; Including, The control unit sets a first correction movement range when the washer fluid is not injected, and sets a second correction movement range when the washer fluid is injected, the first correction movement range is a range narrower than a normal movement range that is set when it is determined that the overrun will not occur, the second correction movement range is the same as the normal movement range, or is narrower than the normal movement range but wider than the first correction movement range; Wiper drive method.

5. Computer, a load detection means for detecting a load applied to a wiper motor that drives the wiper; a control means for determining whether an overrun of the wiper will occur based on a change in a detection value indicating the detected load, and for setting a correction movement range in which a reversal position of the wiper is set depending on whether a washer fluid is injected, as the movement range of the wiper, when it is determined that the overrun will occur; It functions as the control means sets a first correction movement range when the washer fluid is not injected, and sets a second correction movement range when the washer fluid is injected; the first correction movement range is a range narrower than a normal movement range that is set when it is determined that the overrun will not occur, the second correction movement range is the same as the normal movement range, or is narrower than the normal movement range but wider than the first correction movement range; program.

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