Wiping device

Abstract

To inhibit interference of a wiper blade when a power source is driven by a drive signal generated based on a drive command generated in a feed forward control method.SOLUTION: A wiping device wipes rain water on a surface to be wiped by reciprocating a wiper blade with a predetermined power source and includes: a control unit which generates a drive command at least in a feed forward control method; and a drive circuit which generates a drive signal on the basis of the drive command and outputs the drive signal to the power source. The control unit corrects the drive command according to the drive voltage of the power source.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a wiping device. [Background technology]

[0002] As is well known, various types of moving vehicles are equipped with a wiping device that wipes rainwater off the surface (wiped surface) of a windshield or a rear windshield. This wiping device wipes rainwater off the wiped surface by reciprocating wiper blades using a motor (power source). Patent Document 1 listed below discloses an example of such a wiping device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-143499 A Summary of the Invention [Problem to be solved by the invention]

[0004] By the way, as a control method for a motor, a feedback control method and a feedforward control method are known. In the above-mentioned wiping device, a drive command for controlling a drive circuit of a motor (power source) is generated by appropriately using either or both of the feedback control method and the feedforward control method.

[0005] Also, an inverter circuit is known as a motor drive circuit. This inverter circuit generates a drive signal by switching DC power based on the drive command. In the wiping device described above, the output power of a battery mounted on the vehicle is converted into the DC power and input to the inverter circuit, and the drive signal is generated by switching the DC power.

[0006] However, when a drive signal is generated by an inverter circuit based on a drive command generated by a feedforward control method, if the battery voltage, i.e., the drive voltage of the motor (power source), drops, the counter force acting on the wiper blade drops, which may cause the wiper blade to overrun and interfere with an interfering part such as a pillar of a moving vehicle.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a wiping device that can suppress interference with wiper blades when a power source is driven by a drive signal based on a drive command generated by a feedforward control method. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the present invention adopts, as a first solution relating to a wiping device, a wiping device that wipes rainwater off a surface to be wiped by reciprocating a wiper blade using a predetermined power source, which is equipped with at least a control unit that generates a drive command using a feedforward control method, and a drive circuit that generates a drive signal based on the drive command and outputs the drive signal to the power source, and the control unit corrects the drive command in accordance with the drive voltage of the power source.

[0009] In the present invention, as a second solution related to the wiping device, in the above-mentioned first solution, a means is adopted in which the wiper blade moves from the lower reversal position to the upper reversal position by rotating the power source in the forward direction, and moves from the upper reversal position to the lower reversal position by rotating the power source in the reverse direction, and the control unit generates the drive command by the feedforward control method during an initial period when the wiper blade moves from the lower reversal position to the upper reversal position.

[0010] The present invention employs, as a third solution related to the wiping device, a solution in which, in the first or second solution described above, the drive circuit is an inverter circuit that generates the drive signal by switching a DC power supply supplied from an external source, and the drive command is a duty ratio for switching the inverter circuit.

[0011] The present invention employs, as a fourth solving means related to the wiping device, any one of the first to third solving means, a means in which the pair of wiper blades are reciprocated by one power source.

[0012] The present invention adopts a fifth solution relating to a wiping device, in which, in any of the first to third solutions described above, the power source is provided in a pair and reciprocates the wiper blade corresponding to itself among the pair of wiper blades. Effect of the Invention

[0013] According to the present invention, it is possible to provide a wiping device capable of suppressing interference of wiper blades when a power source is driven by a drive signal based on a drive command generated by a feedforward control method. [Brief description of the drawings]

[0014] [Figure 1] 1 is a block diagram showing a functional configuration of a wiping device according to a first embodiment of the present invention. [Diagram 2] FIG. 3 is a characteristic diagram showing a control period in the first embodiment of the present invention. [Diagram 3] 1 is a circuit diagram showing a configuration of a drive circuit in a first embodiment of the present invention. [Figure 4] 5 is a flowchart showing the operation of the wiping device according to the first embodiment of the present invention. [Diagram 5] 1A is a characteristic diagram showing the correction of the duty ratio in the first embodiment of the present invention, and FIG. 1B is a schematic diagram showing the reciprocating motion of a wiper blade, and FIG. [Figure 6]5 is a waveform diagram showing the operation of the wiping device according to the first embodiment of the present invention. FIG. [Figure 7] FIG. 6 is a block diagram showing a functional configuration of a wiping device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [First embodiment] First, a first embodiment of the present invention will be described with reference to Figures 1 to 5. A wiping device A according to the first embodiment is mounted on various types of mobile vehicles such as gasoline-powered automobiles, hybrid automobiles, and electric automobiles, and is a device for wiping rainwater adhering to the surface (wiped surface W) of a member to be wiped such as a windshield or rear windshield.

[0016] 1, the wiping device A according to the first embodiment includes a pair of wiper blades 1d, 1p, a pair of wiper arms 2d, 2p, a link mechanism 3, a motor 4 (power source), an angle detection circuit 5, a control unit 6, and a drive circuit 7. In addition, the control unit 6 includes a ROM (Read Only Memory) 61, a RAM (Random Access Memory) 62, and a CPU (Central Processing Unit) 63 as shown in the figure.

[0017] This wiping device A employs a single motor drive system in which a pair of wiper blades 1d, 1p are driven by a single motor 4 (power source) by mechanically connecting a pair of wiper arms 2d, 2p with a link mechanism 3. In other words, this wiping device A has a basic configuration in which a single motor 4 (power source) reciprocates the pair of wiper blades 1d, 1p.

[0018] As shown in Fig. 1, the wiping device A employs a parallel wiping system in which a pair of wiper blades 1d, 1p move in the same direction. That is, when one wiper arm 2d, i.e., the wiper arm 2d on the driver's seat side, moves upward from bottom to top, the other wiper arm 2p, i.e., the wiper arm 2p on the passenger's seat side, also moves upward from bottom to top. Also, when the wiper arm 2d on the driver's seat side moves downward from top to bottom, the wiper arm 2p on the passenger's seat side also moves downward from top to bottom.

[0019] Here, in the symbols in Fig. 1, "d" indicates members and parts related to the driver's seat side of the vehicle. Also, "p" indicates members and parts related to the passenger's seat side of the vehicle. In Fig. 1, symbol Rd indicates the wiping range of wiper blade 1d on the driver's seat side (driver's seat wiping range). Also, symbol Rp indicates the wiping range of wiper blade 1p on the passenger's seat side (passenger's seat wiping range).

[0020] The driver's seat wiping range Rd is a range from the lower reversal position PLd to the upper reversal position PUd as the movement trajectory of the driver's seat side wiper blade 1d. The lower reversal position PLd is a position where the driver's seat side wiper blade 1d switches from a downward motion to an upward motion on the wiped surface W. The upper reversal position PUd is a position where the driver's seat side wiper blade 1d switches from an upward motion to a downward motion on the wiped surface W.

[0021] The passenger side wiping range Rp is a range from the lower reversal position PLp to the upper reversal position PUp as the movement trajectory of the passenger side wiper blade 1p. The lower reversal position PLp is a position where the passenger side wiper blade 1p switches from a downward motion to an upward motion on the wiped surface W. The upper reversal position PUp is a position where the passenger side wiper blade 1p switches from a downward motion to an upward motion on the wiped surface W.

[0022] As shown in the figure, the pair of wiper blades 1d, 1p are rod-shaped members arranged on the surface to be wiped W. The pair of wiper blades 1d, 1p abut against the surface to be wiped W and wipe away rainwater present on the surface to be wiped by performing a reciprocating motion (oscillating motion) on the surface to be wiped W. The pair of wiper blades 1d, 1p is mechanically connected to a motor 4 via a pair of wiper arms 2d, 2p.

[0023] That is, the wiper blade 1d on the driver's side is connected to the motor 4 via a wiper arm 2d provided on the driver's side. The wiper blade 1p on the passenger's side is connected to the motor 4 via a wiper arm 2p and a link mechanism 3 provided on the passenger's side.

[0024] As shown in the figure, the pair of wiper arms 2d, 2p are rod-shaped members, one end of which is connected to the middle of the pair of wiper blades 1d, 1p, and the other end of which is connected to the pair of wiper shafts Td, Tp. That is, the wiper arm 2d on the driver's seat side has one end connected to the middle of the wiper blade 1d on the driver's seat side, and the other end connected to the wiper shaft Td on the driver's seat side.

[0025] On the other hand, one end of the passenger side wiper arm 2p is connected to a middle portion of the passenger side wiper blade 1p, and the other end is connected to the passenger side wiper shaft Tp. Note that such a pair of wiper arms 2d, 2p are members included in the components of the pair of wiper blades 1d, 1p.

[0026] The pair of wiper arms 2d, 2p function as power transmission parts that mechanically transmit the rotational power of the motor 4 to the pair of wiper blades 1d, 1p. The pair of wiper arms 2d, 2p also function as biasing members that press the pair of wiper blades 1d, 1p against the surface W to be wiped with a predetermined pressing force.

[0027] The link mechanism 3 is a mechanical component that is mechanically connected to the other ends of the pair of wiper arms 2d, 2p and the output shaft of the motor 4. The link mechanism 3 has a support shaft fixed to the vehicle and is rotatable around the support shaft. The output shaft of the motor 4 is connected to the link mechanism 3. The motor 4 reciprocates the pair of wiper blades 1d, 1p by controlling the rotation angle of the link mechanism 3. The motor 4 is the power source in the first embodiment.

[0028] The angle detection circuit 5 outputs an angle signal proportional to the rotation angle of the motor 4 to the CPU 63. This angle signal is a signal indicating the operating angle of the pair of wiper blades 1d, 1p mechanically connected by the link mechanism 3. In detail, such an angle signal is composed of a relative position signal indicating the relative position of the pair of wiper blades 1d, 1p and an absolute position signal indicating the absolute position of the pair of wiper blades 1d, 1p.

[0029] The relative position signal is a pulse signal (motor pulse) generated with the rotation of the motor 4, and is a pulse signal (pulse train) with a number of pulses proportional to the rotation angle of the motor 4. In contrast, the absolute position signal is a single pulse signal generated when the pair of wiper blades 1d, 1p reach a control reference position. The control reference position is, for example, the bottom reversal positions PLd, PLp.

[0030] The control unit 6 generates a drive command by a feedback control method or a feedforward control method based on a switch signal input from a higher-level control device, a power supply voltage Vcc input from the drive circuit 7, and an angle signal input from the angle detection circuit 5. The control unit 6 outputs the drive command to the drive circuit 7, thereby performing feedback control or feedforward control of the pair of wiper blades 1d, 1p.

[0031] The power supply voltage Vcc is the voltage of the drive signal generated by the drive circuit 7. The drive command is a signal that controls the generation of the drive signal in the drive circuit 7, and is a PWM (Pulse Width Modulation) signal when the drive circuit 7 is an inverter circuit. The switch signal is a higher-level control command that instructs the wiping device A to turn on / off the wiper switch provided on the vehicle, specify heavy rain mode, turn on / off the mist switch, intermittent operation (Lo, Hi, INT), etc.

[0032] In the control unit 6, the ROM 61 is a non-volatile memory. The ROM 61 stores a control program executed by the CPU 63 to feedback control the pair of wiper blades 1d, 1p. The ROM 61 also stores an operation map required for the CPU 63 to execute the control program.

[0033] The operation map is control data that is referred to when the CPU 63 executes control processing based on the control program. The operation map is, for example, a group of control data that indicates time-series target speeds of the pair of wiper blades 1d, 1p.

[0034] The RAM 62 is a volatile memory. This RAM 62 temporarily stores various calculation data generated when the CPU 63 executes a control program. This RAM 62 temporarily stores, for example, time-series data of the drive voltage (power supply voltage Vcc).

[0035] The CPU 63 executes a control program pre-stored in the ROM 61 to generate a drive command (PWM signal) based on a feedback control method or a feedforward control method and output it to the drive circuit 7. When executing the control program, the CPU 63 refers to a switch signal input from a higher-level control device, an angle signal input from the angle detection circuit 5, and an operation map pre-stored in the ROM 61.

[0036] That is, the CPU 63 generates a drive command (PWM signal) by referring to the switch signal, the angle signal, and the operation map based on the control program. The PWM signal is a control command whose duty ratio is corrected based on the power supply voltage Vcc and which makes the moving speed of the pair of wiper blades 1d, 1p obtained from the angle signal equal to the target speed indicated by the operation map.

[0037] Here, the CPU 63 (controller 6) switches the generation process of the drive command (PWM signal) based on the feedback control method or the feedforward control method as shown in Fig. 2. That is, the CPU 63 (controller 6) generates the drive command (PWM signal) by the feedforward control method during the initial period Ta when the pair of wiper blades 1d, 1p move from the lower reversal positions PLd, PLp to the upper reversal positions PUd, Pup.

[0038] The initial period Ta when Lo is activated and the surface to be wiped W is wet is, for example, 45 ms. The initial period Ta when Hi is activated and the surface to be wiped W is wet is, for example, 42 ms. The initial period Ta is variably set depending on the load state of the motor 4, such as the wetness state of the surface to be wiped W.

[0039] Further, the CPU 63 (controller 6) generates a drive command (PWM signal) by a feedback control method during a period Tb other than the initial period Ta. The CPU 63 (controller 6) thus performs a process of generating a drive command (PWM signal) based on a feedforward control method at a specific position in the reciprocating motion of the pair of wiper blades 1d, 1p.

[0040] The drive circuit 7 is a signal generating circuit that generates a drive signal based on a drive command (PWM signal) input from the CPU 63 (control unit 6). The drive circuit 7 outputs a drive signal to the motor 4 to rotate the motor 4 forward (normal rotation) or reverse (reverse rotation) at a desired rotation speed. The drive circuit 7 also outputs the power supply voltage Vcc used to generate the drive signal to the CPU 63 as a drive voltage.

[0041] Such a driving circuit 7 is, for example, an inverter circuit as shown in Fig. 3. That is, the driving circuit 7 includes four N-type MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) 7a to 7d as switching transistors. The driving circuit 7 generates a driving signal by switching a power supply voltage Vcc supplied from a battery of the mobile vehicle as a driving voltage by the four N-type MOSFETs 7a to 7d (multiple switching transistors).

[0042] Of the four N-type MOSFETs 7a to 7d, the first N-type MOSFET 7a has a source terminal connected to an output terminal of a battery that supplies a power supply voltage Vcc to the drive circuit 7, and a drain terminal connected to the second N-type MOSFET 7b and a first input terminal of the motor 4 (power source). In addition, the first N-type MOSFET 7a has a gate terminal connected to a first output terminal of the CPU 63, and a first PWM signal is input from the CPU 63.

[0043] The second N-type MOSFET 7b has a source terminal connected to the first N-type MOSFET 7a and the first input terminal of the motor 4, and a drain terminal grounded. In addition, the second N-type MOSFET 7b has a gate terminal connected to the second output terminal of the CPU 63, and receives the second PWM signal from the CPU 63.

[0044] The third N-type MOSFET 7c has a source terminal connected to the output terminal of the battery, and a drain terminal connected to the fourth N-type MOSFET 7d and a second input terminal of the motor 4 (power source). The third N-type MOSFET 7c has a gate terminal connected to the third output terminal of the CPU 63, and receives a third PWM signal from the CPU 63.

[0045] The fourth N-type MOSFET 7d has a source terminal connected to the third N-type MOSFET 7c and the second input terminal of the motor 4, and a drain terminal grounded. In addition, the fourth N-type MOSFET 7d has a gate terminal connected to the fourth output terminal of the CPU 63, and receives the fourth PWM signal from the CPU 63.

[0046] In the drive circuit 7, the first N-type MOSFET 7a is set to the ON state by a first PWM signal, the second N-type MOSFET 7b is set to the OFF state by a second PWM signal, the third N-type MOSFET 7c is set to the OFF state by a third PWM signal, and the fourth N-type MOSFET 7d is set to the ON state by a fourth PWM signal, thereby causing a forward drive current In to flow through the motor 4. This drive current In rotates the motor 4 in the forward direction, thereby causing the pair of wiper blades 1d, 1p to perform an upward movement.

[0047] Furthermore, the drive circuit 7 causes the first N-type MOSFET 7a to be set to the OFF state by the first PWM signal, the second N-type MOSFET 7b to be set to the ON state by the second PWM signal, the third N-type MOSFET 7c to be set to the ON state by the third PWM signal, and further the fourth N-type MOSFET 7d to be set to the OFF state by the fourth PWM signal, thereby passing a reverse drive current Ir through the motor 4. This drive current Ir rotates the motor 4 in the reverse direction, thereby causing the pair of wiper blades 1d, 1p to move downward.

[0048] Next, a characteristic operation of the wiping device A according to the first embodiment will be described with reference to the flowchart shown in Fig. 4. Note that this flowchart shows the procedure of control processing in the CPU 63 (control unit 6).

[0049] First, the control process of the CPU 63 (control unit 6) in the above-mentioned initial period Ta will be described. The CPU 63 (control unit 6) executes a control program to generate a drive command (PWM signal) based on a feedforward control method in the initial period Ta.

[0050] In the process of generating a drive command (PWM signal) in the initial period Ta, the CPU 63 (controller 6) detects the power supply voltage Vcc (drive voltage) input from the drive circuit 7 as a detection voltage V1 (step S1). Then, the CPU 63 sequentially calculates the reference duty ratio in a predetermined time step when the drive voltage (power supply voltage Vcc) is a standard value V0 (step S2).

[0051] "D0" in Fig. 5(a) is the reference duty ratio when the drive voltage (power supply voltage Vcc) is 14V (standard value V0). The initial period Ta is a period during which the motor speed gradually increases as shown in Fig. 2. Therefore, in the initial period Ta, the reference duty ratio D0 is set to increase gradually over time so as to gradually increase the motor speed.

[0052] After calculating the reference duty ratio D0 in the initial period Ta in this way, the CPU 63 corrects the reference duty ratio using the detection voltage V1 acquired in step S1 and the standard value V0 of the power supply voltage Vcc (step S3). That is, the CPU 63 calculates the duty ratio D1 corresponding to the detection voltage V1 based on the following correction formula (1).

[0053] D1 = D0 × V1 / V0 (1) 5(a), "D1" is the duty ratio corresponding to the detection voltage V1 calculated based on the above formula (1). This duty ratio D1 is a value larger than the reference duty ratio corresponding to 14 V (standard value V0) as shown in the figure.

[0054] The CPU 63 (controller 6) generates a PWM signal with a duty ratio D1 and outputs it as a drive command to the drive circuit 7. Then, the drive circuit 7 generates a drive signal corresponding to the PWM signal (drive command) and outputs it to the motor 4. As a result, the pair of wiper blades 1d, 1p reciprocate at a speed corresponding to the drive signal input from the drive circuit 7, that is, the PWM signal (drive command) generated by the CPU 63.

[0055] Fig. 6 shows an example of a PWM signal with a reference duty ratio D0 (upper part) and a PWM signal with a duty ratio D1 (lower part). As shown in Fig. 5, when the drive voltage drops from a standard value V0 (14V) to a detection voltage V1 (10V), the reference duty ratio D0 increases to a duty ratio D1. That is, the CPU 63 (controller 6) compensates for the drop in drive power to the motor 4 caused by the drop in drive voltage by increasing the duty ratio.

[0056] The wiping device A of the first embodiment has a basic configuration in which a pair of wiper blades 1d, 1p are reciprocated by one motor 4 (power source), and is equipped with a CPU 63 (control unit 6) that generates a PWM signal (drive command) using at least a feedforward control method, and a drive circuit 7 that generates a drive signal based on the PWM signal and outputs the drive signal to the motor 4, and the CPU 63 (control unit 6) corrects the duty ratio of the PWM signal in accordance with the drive voltage (power supply voltage Vcc) of the motor 4.

[0057] That is, according to the first embodiment, when the motor 4 (power source) is driven by a drive signal based on a PWM signal (drive command) generated by a feedforward control method, it is possible to suppress a shortage of the counter force of the pair of wiper blades 1d, 1p caused by a drop in the drive voltage. Therefore, according to the first embodiment, it is possible to suppress interference between the pair of wiper blades 1d, 1p and pillars, etc. caused by a drop in the drive voltage.

[0058] In addition, in the wiping device A of the first embodiment, the pair of wiper blades 1d, 1p move from the lower reversal positions PLd, PLp to the upper reversal positions PUd, PUp as the motor 4 (power source) rotates in the forward direction, and move from the upper reversal positions PUd, PUp to the lower reversal positions PLd, PLp as the motor 4 (power source) rotates in the reverse direction, and the CPU 63 (control unit 6) generates a PWM signal (drive command) using a feedforward control method during the initial period Ta when the pair of wiper blades 1d, 1p move from the upper reversal positions PUd, PUp to the lower reversal positions PLd, PLp.

[0059] According to the first embodiment, when a PWM signal (drive command) is generated using a feedforward control method in the initial period Ta, it is possible to suppress interference between a pair of wiper blades 1d, 1p and pillars, etc., caused by a decrease in the drive voltage.

[0060] Second Embodiment A second embodiment of the present invention will be described with reference to Fig. 7. A wiping device B according to the second embodiment, like the wiping device A according to the first embodiment, is mounted on various vehicles and wipes rainwater off the surface (wiped surface W) of a windshield or a rear windshield. In Fig. 7, the same components as those in the first embodiment are denoted by the same reference numerals.

[0061] The wiping device B has a basic configuration in which a pair of motors 4d, 4p are provided to reciprocate the corresponding wiper blade of the pair of wiper blades 1d, 1p. The wiping device B has a drive control device 10 as shown in FIG.

[0062] As shown in the figure, the drive control device 10 includes a pair of motors 4d, 4p and a pair of wiper drive control units 10d, 10p. That is, the wiping device B is a dual-motor drive type wiping device. In addition, the wiping device B employs an opposed wiping type in which a pair of wiper blades 1d, 1p move opposite each other as shown in FIG. 7.

[0063] The motor 4d on the driver's seat side includes a motor body 8d and a speed reduction mechanism 9d. The motor 4p on the passenger's seat side includes a motor body 8p and a speed reduction mechanism 9p. A pair of wiper drive controllers 10d and 10p drive and control the pair of motors 4d and 4p, which are power sources.

[0064] Of the pair of wiper drive control units 10d, 10p, the first wiper drive control unit 10d is a drive control unit corresponding to the motor 4d on the driver's seat side, and is equipped with an angle detection circuit 11d, a ROM (Read Only Memory) 12d, a RAM (Random Access Memory) 13d, a communication circuit 14d, a CPU (Central Processing Unit) 15d, and a drive circuit 16d.

[0065] Further, of the pair of wiper drive control units 10d, 10p, the second wiper drive control unit 10p is a drive control unit corresponding to the motor 4p on the passenger side, and is equipped with an angle detection circuit 11p, a ROM (Read Only Memory) 12p, a RAM (Random Access Memory) 13p, a communication circuit 14p, a CPU (Central Processing Unit) 15p, and a drive circuit 16p.

[0066] The motor 4d on the driver's seat side is driven and controlled by the wiper drive control unit 10d, so that the wiper blade 1d on the driver's seat side reciprocates (oscillates) around the wiper shaft Td as a fulcrum. The motor 4p on the passenger's seat side is driven and controlled by the wiper drive control unit 10p, so that the wiper blade 1p on the passenger's seat side reciprocates (oscillates) around the wiper shaft Tp as a fulcrum.

[0067] In the first wiper drive control unit 10d, the angle detection circuit 11d has a function similar to that of the angle detection circuit 5 in the first embodiment, and outputs an angle signal proportional to the rotation angle of the motor main body 8d to the CPU 15d. This angle signal is a signal indicating the operating angle of the wiper blade 1d on the driver's seat side, and is composed of the relative position signal and absolute position signal described in the first embodiment.

[0068] The ROM 12d is a non-volatile memory. The ROM 12d stores a control program for the CPU 15d to feedback control the wiper blade 1d on the driver's seat side. The ROM 12d also stores an operation map required for the CPU 15d to execute the control program. The operation map indicates a target speed of the wiper blade 1d on the driver's seat side.

[0069] The RAM 13d is a volatile memory. The RAM 13d temporarily stores various data generated when the CPU 15d executes the control program. The RAM 13d temporarily stores, for example, time-series data of the power supply voltage Vcc (drive voltage).

[0070] The communication circuit 14d transmits and receives control information to and from the second wiper drive control unit 10p. The communication circuit 14d receives, as the control information, for example, the current position of the wiper blade 1p on the passenger side from the communication circuit 14p of the second wiper drive control unit 10p. The communication circuit 14d also transmits, as the control information, for example, the current position of the wiper blade 1d on the driver side to the communication circuit 14p of the second wiper drive control unit 10p.

[0071] The CPU 15d generates a drive command by executing a control program previously stored in the ROM 12d, and outputs the drive command to the drive circuit 16d. When executing the control program, the CPU 15d refers to a switch signal input from a higher-level control device, an angle signal input from the angle detection circuit 11d, control information input from the communication circuit 14d, a power supply voltage Vcc (drive voltage) input from the drive circuit 16d, and an operation map previously stored in the ROM 12d.

[0072] That is, the CPU 15d generates a drive command by referring to the switch signal, the angle signal, the control information, the power supply voltage Vcc (drive voltage) and the operation map based on the control program. The drive command is a control command that instructs the drive circuit 16d to drive the wiper blade 1d on the driver's seat side and takes into account the drive control state of the wiper blade 1p on the passenger's seat side in the second wiper drive control unit 10p.

[0073] In other words, this drive command controls the driver's side wiper blade 1d so that the movement speed of the driver's side wiper blade 1d obtained from the angle signal becomes equal to the target speed in the operation map and is synchronized with the movement of the passenger side wiper blade 1p.

[0074] The drive circuit 16d generates a drive signal based on a drive command input from the CPU 15d, and outputs the drive signal to the motor 4d. The drive circuit 16d is an inverter circuit including a plurality of switching transistors as shown in FIG.

[0075] Such a drive circuit 16d generates a drive signal by switching a power supply voltage Vcc supplied from a battery of a moving vehicle as a drive voltage using four N-type MOSFETs 7a to 7d (multiple switching transistors). Note that in this case, the drive command is a PWM (Pulse Width Modulation) signal whose duty ratio is variably set according to the deviation between the target speed and the moving speed of the wiper blade 1d on the driver's seat side.

[0076] On the other hand, in the second wiper drive control unit 10p, the angle detection circuit 11p has a function similar to that of the angle detection circuit 5 in the first embodiment, and outputs an angle signal proportional to the rotation angle of the motor main body 8p to the CPU 15p. This angle signal is a signal indicating the operating angle of the passenger side wiper blade 1p, and is composed of the relative position signal and absolute position signal described in the first embodiment.

[0077] The ROM 12p is a non-volatile memory. The ROM 12p stores a control program for the CPU 15p to feedback control the wiper blade 1p on the passenger side. The ROM 12p also stores an operation map required for the CPU 15p to execute the control program.

[0078] The operation map indicates a target speed of the wiper blade 1p on the passenger side. The control program stored in the ROM 12p is substantially the same as the control program stored in the ROM 12d of the first wiper drive control unit 10d.

[0079] The RAM 13p is a volatile memory. The RAM 13p temporarily stores various data generated when the CPU 15p executes a control program. For example, the RAM 13p temporarily stores time-series data of the power supply voltage Vcc.

[0080] The communication circuit 14p transmits and receives control information to and from the first wiper drive control unit 10d. The communication circuit 14p receives, as the control information, for example, the current position of the wiper blade 1d on the driver's seat side from the communication circuit 14d of the first wiper drive control unit 10d. The communication circuit 14p also transmits, as the control information, for example, the current position of the wiper blade 1p on the passenger's seat side to the communication circuit 14d of the first wiper drive control unit 10d.

[0081] The CPU 15p generates a drive command by executing a control program previously stored in the ROM 12p, and outputs the drive command to the drive circuit 16p. When executing the control program, the CPU 15p refers to a switch signal input from a higher-level control device, an angle signal input from the angle detection circuit 11p, control information input from the communication circuit 14p, a power supply voltage Vcc (drive voltage) input from the drive circuit 16p, and an operation map previously stored in the ROM 12p.

[0082] That is, the CPU 15p generates a drive command by referring to the switch signal, the angle signal, the control information, the power supply voltage Vcc, and the operation map based on the control program. The drive command is a control command that instructs the drive circuit 16p to drive the wiper blade 1p on the passenger side and takes into account the drive control state of the wiper blade 1d on the driver side in the first wiper drive control unit 10d.

[0083] In other words, this drive command controls the passenger side wiper blade 1d so that the movement speed of the passenger side wiper blade 1p obtained from the angle signal becomes equal to the target speed in the operation map and is synchronized with the movement of the driver's side wiper blade 1p.

[0084] The drive circuit 16p generates a drive signal based on a drive command input from the CPU 15p, and outputs the drive signal to the motor 4p. The drive circuit 16p is, for example, an inverter circuit including a plurality of switching transistors as shown in FIG.

[0085] Such a drive circuit 16p generates a drive signal by switching a power supply voltage Vcc supplied from a battery of a moving vehicle as a drive voltage using four N-type MOSFETs 7a to 7d (multiple switching transistors). Note that in this case, the drive command is a PWM signal whose duty ratio is variably set according to the deviation between the target speed and the moving speed of the wiper blade 1p on the passenger side.

[0086] Next, a characteristic operation of the wiping device B according to the second embodiment will be described. In this wiping device B, a first wiper drive control unit 10d controls the rotation of a motor 4d on the driver's seat side based on a control program, so that a wiper blade 1d on the driver's seat side performs a wiping operation on a surface to be wiped W. Also, in this wiping device B, a second wiper drive control unit 10p controls the rotation of a motor 4p on the passenger's seat side based on a control program, so that a wiper blade 1p on the passenger's seat side performs a wiping operation on a surface to be wiped W.

[0087] In addition, in the wiping device B, control information of the first wiper drive control unit 10d and control information of the second wiper drive control unit 10p are exchanged with each other through a pair of communication circuits 14d and 14p, so that the wiper blade 1d on the driver's seat side and the wiper blade 1p on the passenger's seat side perform wiping operations in synchronization with each other.

[0088] The control of the wiper blade 1d on the driver's seat side by the first wiper drive control unit 10d is similar to the control of the wiper blade 1p on the passenger's seat side by the second wiper drive control unit 10p. That is, the pair of CPUs 15d, 15p in the pair of wiper drive control units 10d, 10p calculate and correct the duty ratio of a PWM signal (drive command) according to the flowchart shown in Fig. 4, similar to the CPU 63 in the first embodiment, and output the PWM signal to the pair of drive circuits 16d, 16p.

[0089] The pair of drive circuits 16d, 16p generate drive signals corresponding to the PWM signals (drive commands) and output them to the pair of motors 4d, 4p. As a result, the pair of wiper blades 1d, 1p reciprocate at a speed corresponding to the drive signals input from the pair of drive circuits 16d, 16p, that is, the PWM signals (drive commands) generated by the pair of CPUs 15d, 15p.

[0090] The wiping device B of the second embodiment has a basic configuration in which a pair of motors 4d, 4p are provided and each motor reciprocates the corresponding wiper blade of the pair of wiper blades 1d, 1p.The wiping device B also has a control unit 6 that generates a PWM signal (drive command) using at least a feedforward control method, and a drive circuit 7 that generates a drive signal based on the PWM signal and outputs the drive signal to the motor 4, and the control unit 6 corrects the duty ratio of the PWM signal in accordance with the drive voltage (power supply voltage Vcc) of the motor 4.

[0091] That is, according to the second embodiment, when the motor 4 (power source) is driven by a drive signal based on a PWM signal (drive command) generated by a feedforward control method, it is possible to suppress a shortage of the counter force of the pair of wiper blades 1d, 1p caused by a drop in the drive voltage. Therefore, according to the second embodiment, it is possible to suppress interference between the pair of wiper blades 1d, 1p and pillars, etc. caused by a drop in the drive voltage.

[0092] The present invention is not limited to the above-described embodiments, and various modifications are possible. In the above embodiment, a case where the drive command (PWM signal) is generated by the feedforward control method during the initial period Ta when the pair of wiper blades 1d, 1p move from the lower reversal positions PLd, PLp to the upper reversal positions PUd, Pup has been described, but the present invention is not limited to this. The supplementary invention is also applicable to a case where the drive command (PWM signal) is generated by the feedforward control method during the entire period of the reciprocating motion of the pair of wiper blades 1d, 1p. [Explanation of symbols]

[0093] A, B... wiping device, W... wiped surface, PUd, PUp... upper inversion position, PLd, PLp... lower inversion position, Rd, Rp... wiping range, Td, Tp... fulcrum, 1d, 1p... wiper blade, 2d, 2p... wiper arm, 3... link mechanism, 4, 4d, 4p... motor (power source), 5... angle detection circuit, 6... control unit, 61... ROM, 62... RAM, 63... CPU, 7... drive circuit, 8d, 8p... motor body, 9d, 9p... reduction mechanism, 10... drive control device, 10d, 10p... wiper drive control unit, 11d, 11p... angle detection circuit, 12d, 12p... ROM, 13d, 13p... RAM, 14d, 14p... communication circuit, 15d, 15p... CPU, 16d, 16p... drive circuit

Claims

1. A wiping device that wipes rainwater off a surface to be wiped by reciprocating a wiper blade using a predetermined power source, A control unit that generates a drive command at least by a feedforward control method; a drive circuit that generates a drive signal based on the drive command and outputs the drive signal to the power source; The wiping device according to claim 1, wherein the control unit corrects the drive command in response to a drive voltage of the power source.

2. The wiper blade is moved from a lower inverted position to an upper inverted position by the power source rotating in a forward direction, and is moved from the upper inverted position to the lower inverted position by the power source rotating in a reverse direction. The wiping device according to claim 1 , wherein the control unit generates the drive command by the feedforward control method during an initial period when the wiper blade moves from the lower reversing position to the upper reversing position.

3. the drive circuit is an inverter circuit that generates the drive signal by switching a DC power supply that is supplied from an external source; 3. The wiping device according to claim 1, wherein the drive command is a duty ratio for switching of the inverter circuit.

4. 3. The wiping device according to claim 1, wherein the pair of wiper blades are reciprocated by a single power source.

5. 3. The wiping device according to claim 1, wherein the power source is provided in a pair, and each of the power sources reciprocates the wiper blade corresponding to itself among the pair of wiper blades.

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