Patent Grant
10116173
The present invention relates to a parking assistance device and a parking assistance method.
A wireless power supply system which charges a battery included in a vehicle by contactlessly supplying power to the vehicle is conventionally known. The wireless power supply system performs charging with a power transmitting coil on a ground side aligned with (facing) a power receiving coil on a vehicle side. There is known a method of detecting misalignment between the power transmitting coil and the power receiving coil, including calculating a positional relationship between the power transmitting coil and the power receiving coil by using a camera, for aligning the power receiving coil with (cause the power receiving coil to face) the power transmitting coil (see Patent Literature 1).
Patent Literature 1: Japanese Patent Application Publication No. 2011-15549
However, in the method described in Patent Literature 1, the camera is used to calculate the positional relationship between the power transmitting coil and the power receiving coil, and this is costly.
The present invention has been made in view of the problem described above and an object thereof is to provide a parking assistance device and a parking assistance method which can detect misalignment between a power transmitting coil and a power receiving coil with a low-cost configuration.
A parking assistance device and a parking assistance method in one aspect of the present invention are used in a wireless power supply system which performs wireless power supply between a power transmitting coil on a ground side and a power receiving coil on a vehicle side. The parking assistance device and the parking assistance method: detect magnetic flux in a height direction of the vehicle which is generated by the power transmitting coil, by using three or more coils aligned in one direction in a plan view of the vehicle; and detect misalignment between the power transmitting coil and the power receiving coil in the one direction, based on a decrease in the magnetic flux in the height direction of the vehicle which is detected by the three or more coils.
Part (a) of
Parts (a) to (c) of
Parts (a) to (c) of
Parts (a) to (c) of
Part (a) of
Part (a) of
Parts (a) to (e) of
First and second embodiments are described with reference to the drawings. In the description of the drawings, the same parts are denoted by the same reference numerals and description thereof is omitted.
A parking assistance device in the first embodiment of the present invention is applied to a wireless power supply system which performs wireless power supply between a power transmitting device including a power transmitting coil 20 on a ground side and a power receiving device including a power receiving coil 10 on a vehicle 1 side as illustrated in
The power transmitting device on the ground side includes the power transmitting coil 20 installed on the ground in a parking space or the like and a power source box 2 connected to the power transmitting coil 20. The power source box 2 includes a power unit 21 which excites the power transmitting coil 20 by causing an electric current to flow through the power transmitting coil 20, a ground controller 22 which controls operations of the power unit 21, and a communication unit 23 which wirelessly communicates with the power receiving device on the vehicle 1 side. The ground controller 22 can be formed as an integral computer including, for example, a central processing unit (CPU) and storage units such as a RAM, a ROM, and a hard disk.
The power receiving device on the vehicle 1 side includes the power receiving coil 10, a rectifying and smoothing circuit 12, the vehicle controller 11, a battery (electric load) 13, a communication unit 14, and an output unit (human-machine interface (HMI)) 15. The power receiving coil 10 is arranged at an appropriate position in a bottom portion of the vehicle 1 to face the power transmitting coil 20 when the vehicle 1 is parked at a predetermined position in a parking space. The power receiving coil 10 supplies the received power to the battery 13.
The rectifying and smoothing circuit 12 rectifies and smooths an AC voltage received by the power receiving coil 10. The battery 13 is charged by the voltage received by the power receiving coil 10. The vehicle controller 11 controls operations of the rectifying and smoothing circuit 12. The vehicle controller 11 can be formed as an integral computer including, for example, a central processing unit (CPU) and storage units such as a RAM, a ROM, and a hard disk. The communication unit 14 communicates with the power source box 2. The output unit 15 includes a liquid crystal display of a navigation device or the like, a speaker, a lamp, and the like.
The sub-coils 31 to 33 detect the magnetic flux in the height direction of the vehicle 1 which is generated by the power transmitting coil 20 while the vehicle 1 moves to the predetermined position in the parking space and stops, and output the detected magnetic flux to the vehicle controller 11 as electromagnetic signals.
As illustrated in parts (a) and (b) of
The sub-coils 31 to 33 are arranged in a row in a vehicle width direction on a lower portion of the power receiving coil 10. The sub-coil 32 is arranged at a center position in the vehicle width direction. The two sub-coils 31 and 33 are arranged at equal intervals at positions symmetric to each other with respect to the sub-coil 32. The sub-coils 31 to 33 are arranged on a rear side of the vehicle 1 relative to the center P1 of the power receiving coil 10 (lower side in the sheet of part (a) of
Next, by using parts (a) to (c) of
As illustrated in parts (a) to (c) of
Meanwhile, the magnetic flux in a region A0 above the power transmitting coil 20 illustrated in part (b) of
Parts (a) to (c) of
As illustrated in parts (a) to (c) of
Positions where the sub-coils 31 to 33 are arranged are appropriately set depending on the shape, size, and the like of the power transmitting coil 20. Parts (a) to (c) of
As illustrated in part (b) of
The vehicle controller (misalignment detection unit) 11 illustrated in
For example, when the power receiving coil 10 is aligned with the power transmitting coil 20 in the vehicle width direction as illustrated in part (a) of
In this case, the first threshold (zero determination threshold) is set to distinguish the portion of low-level magnetic flux in the height direction, and is set appropriately depending on the magnetic flux density and the like in the portion of low-level magnetic flux in the height direction. The second threshold is appropriately set to be equal to or higher than the first threshold (specifically, the same value as the first threshold or a higher value than the first threshold). The first and second thresholds are, for example, preset and stored in a memory of the vehicle controller 11.
Meanwhile, when the positional relationship between the power transmitting coil 20 and the power receiving coil 10 is as illustrated in parts (b) and (c) of
The output unit 15 illustrated in
Next, an example of a parking assistance method (misalignment detection method) in the first embodiment of the present invention is described with reference to the flowchart of
In step S101, when the vehicle 1 comes close to a parking space, the sub-coils 31 to 33 detect voltages V1t to V3t and output them to the vehicle controller 11 as electromagnetic signals. In step S102, when excitation is received from the ground side, the vehicle controller 11 performs the effective value processing on the voltages V1t to V3t and obtains voltages V1 to V3 corresponding to the magnetic flux in the height direction.
In step S103, the vehicle controller 11 determines whether at least one of the voltages V1 to V3 is higher than the zero determination threshold V0. When the voltages V1 to V3 are all determined to be equal to or lower than the zero determination threshold V0, the processing proceeds to step S104 and the output unit 15 notifies the user that there is no power transmitting coil 20 near the power receiving coil 10. Meanwhile, when the vehicle controller 11 determines that at least one of the voltages V1 to V3 is higher than the zero determination threshold in step S103, the processing proceeds to step S105 and the output unit 15 first notifies the user that the power transmitting coil 20 is near the power receiving coil 10.
In step S106, the vehicle controller 11 determines whether the voltages V1, V3 are equal to or lower than the zero determination threshold (first threshold) V0, and also determines whether the voltage V2 is equal to or higher than the zero determination threshold (second threshold) V0. For example, when the positional relationship is as illustrated in part (a) of
Meanwhile, for example, when the positional relationship is as illustrated in part (b) or (c) of
As described above, in the first embodiment of the present invention, the misalignment is detected based on the decrease in the magnetic flux in the height direction by utilizing the short-circuit phenomenon of the magnetic flux above and near the somewhat inner portion of the power transmitting coil 20. This enables detection of the misalignment between the power transmitting coil 20 and the power receiving coil 10 with a low-cost configuration.
Moreover, at least three sub-coils 31 to 33 are arranged in the vehicle width direction to detect the misalignment. This enables detection of the misalignment in the vehicle width direction. Furthermore, the sub-coils 31 to 33 are aligned in the vehicle width direction at positions on the front side or the rear side of the vehicle 1 relative to the center of the power receiving coil 10 below the power receiving coil 10. This enables early detection of the misalignment in the vehicle width direction when the vehicle 1 enters the parking position from the side where the sub-coils 31 to 33 are aligned.
In the first embodiment of the present invention, description is given of the case where the magnetic flux in the height direction is detected by utilizing the three sub-coils 31 to 33. Meanwhile, as a first modified example of the present invention, description is given of the case where the misalignment is detected by utilizing the power receiving coil 10 instead of the sub-coil 32 at the center.
In the first modified example, as illustrated in parts (a) and (b) of
In the first modified example, the magnetic flux in the height direction is detected by utilizing the power receiving coil 10 together with the two sub-coils 31, 33. This enables detection of the presence or absence of the misalignment as in the first embodiment while reducing the number of sub-coils 31, 33 for detecting the magnetic flux in the height direction.
In the first embodiment of the present invention, description is given of the case where the sub-coils 31 to 33 are arranged in contact with the lower portion of the power receiving coil 10. Meanwhile, as a second modified example of the present invention, description is given of the case where the sub-coils 31 to 33 are not in contact with the power receiving coil 10.
In the second modified example of the present invention, as illustrated in
In the second modified example, the sub-coils 31 to 33 do not have to be in contact with the power receiving coil 10 and only need to be arranged at positions which are near the lower portion of the power receiving coil 10 and at which the sub-coils 31 to 33 can detect the decrease of the magnetic flux in the height direction generated by the power transmitting coil 20.
As a second embodiment of the present invention, description is given of the case where five coils for detecting the magnetic flux in the height direction are aligned to detect the direction of the misalignment. A parking assistance device in the second embodiment of the present invention includes five sub-coils 31 to 35 as illustrated in parts (a) and (b) of
The sub-coils 31 to 35 are arranged in a row in the vehicle width direction in a plan view of the vehicle 1. The sub-coils 31 to 35 may be arranged on the rear side of the vehicle 1 relative to the center P1 of the power receiving coil 10 or arranged on the front side of the vehicle 1 relative to of the center P1. The sub-coils 31 to 35 are arranged, for example, at equal intervals. The sub-coil 33 at the center is arranged to be aligned with the center P1 of the power receiving coil 10 in the vehicle width direction. The sub-coils 32, 34 are arranged at positions symmetric to each other with respect to the sub-coil 33 at the center. The sub-coils 31, 35 at both ends are arranged at positions symmetric to each other with respect to a set of the sub-coils 32 to 34.
The positions where the sub-coils 31 to 35 are arranged are appropriately set depending on the size, shape, and the like of the power transmitting coil 20. In the second embodiment of the present invention, the sub-coils 31, 35 at both ends are arranged to be in the portion of low-level magnetic flux in the height direction when the power receiving coil 10 is aligned with the power transmitting coil 20 in the vehicle width direction. Note that the sub-coils 31, 35 at both ends do not necessarily have to be arranged in the portion of low-level magnetic flux in the height direction and, for example, one sub-coil may be further arranged outside each of the sub-coils 31, 35.
Parts (a) to (e) of
As illustrated in part (a) of
In the second embodiment of the present invention, the vehicle controller 11 illustrated in
Next, an example of a parking assistance method (misalignment detection method) in the second embodiment of the present invention is described with reference to the flowcharts of
In step S201, the five sub-coils 31 to 35 measure voltages V1t to V5t and output them to the vehicle controller 11. In step S202, when excitation is received from the ground side, the vehicle controller 11 performs the effective value processing on the voltages V1t to V5t of the sub-coils 31 to 35 and obtains voltages V1 to V5 corresponding to the magnetic flux in the height direction.
In step S203, the vehicle controller 11 determines whether at least one of the voltages V1 to V5 is higher than the zero determination threshold V0. Note that the zero determination threshold V0 is appropriately set to such a value that the portion of low-level magnetic flux can be distinguished. When the voltages V1 to V5 are all determined to be equal to or lower than the zero determination threshold V0 (determined to be zero), processing proceeds to step S204 and the output unit 15 notifies the user that there is no power transmitting coil 20 near the power receiving coil 10. Meanwhile, when the vehicle controller 11 determines that at least one of the voltages V1 to V5 is higher than the zero determination threshold V0 in step S203, the processing proceeds to step S205 and the output unit 15 notifies the user that the power receiving coil 10 is near the power transmitting coil 20.
In step S206, the vehicle controller 11 determines whether voltages corresponding to two non-consecutive sub-coils out of the voltages V1 to V5 are equal to or lower than the zero determination threshold V0. For example, when the positional relationship is as illustrated in part (a) of
In step S207, the vehicle controller 11 determines whether the voltages V2 to V4 of the sub-coils 32 to 34 between the sub-coils 31, 35 determined to be zero are higher than the zero determination threshold V0. When the voltages of the sub-coils 32 to 34 between the sub-coils 31, 35 determined to be zero are determined to be higher than the zero determination threshold V0, the center P0 of the power transmitting coil 20 is determined to be on a bisector of a line segment whose endpoints are at the two sub-coils 31, 35 determined to be zero, and the processing proceeds to step S208.
Details of step S208 are described with reference to the flowchart of
Meanwhile, when the vehicle controller 11 determines that the bisector of the line segment whose endpoints are at the two sub-coils 31, 35 determined to be zero does not pass the center P1 of the power receiving coil 10 in step S301, the processing proceeds to step S303. In step S303, the vehicle controller 11 determines whether the bisector passes the left side of the center P1 of the power receiving coil 10 as viewed in the traveling direction. When the bisector is determined to pass the left side of the center P1 of the power receiving coil 10 as viewed in the traveling direction, the processing proceeds to step S304 and the output unit 15 notifies the user to steer to the left since the power transmitting coil 20 is off to the left. Meanwhile, when the bisector is determined to pass the right side of the center P1 of the power receiving coil 10 as viewed in the traveling direction, the processing proceeds to step S305 and the output unit 15 notifies the user to steer to the right since the power transmitting coil 20 is off to the right.
Returning to
In step S209, the vehicle controller 11 determines whether one of the voltages V1, V5 of the sub-coils 31, 35 at both ends is equal to or lower than the zero determination threshold V0. When one of the voltages V1, V5 is determined to be equal to or lower than the zero determination threshold V0 (determined to be zero), the processing proceeds to step S210.
Details of step S210 are described with reference to the flowchart of
Meanwhile, when the voltage V5 is determined to be higher than the zero determination threshold V0 (in other words, the voltage V1 is determined to be equal to or lower than the zero determination threshold V0) in step S401, the processing proceeds to step S403. In step S403, since the power transmitting coil 20 is off to the right as viewed in the traveling direction of the vehicle 1, the output unit 15 notifies the user to steer to the right.
Returning to
Details of step S212 are described with reference to the flowchart of
Meanwhile, when the voltage V1 is determined to be equal to or lower than the voltage V5 in step S501, the processing proceeds to step S503 and the output unit 15 notifies the user to steer to the right since the power transmitting coil 20 is off to the right as viewed in the traveling direction of the vehicle 1.
Returning to
Details of step S213 are described with reference to the flowchart of
In step S601, the vehicle controller 11 determines whether a voltage difference Vtop−Vsec between the highest voltage Vtop and the second highest voltage Vsec is higher than a predetermined threshold Vth. When the voltage difference Vtop−Vsec is higher than the predetermined threshold Vth, the processing proceeds to step S602 and the vehicle controller 11 determines that the power transmitting coil 20 is off to the side of the sub-coil with the highest voltage Vtop (referred to as Posi=1). Meanwhile, when the voltage difference Vtop−Vsec is equal to or lower than the predetermined threshold Vth in step S601, the processing proceeds to step S603.
In step S603, the vehicle controller 11 determines whether a voltage difference Vtop−Vthr between the highest voltage Vtop and the third highest voltage Vthr is higher than the predetermined threshold Vth. When the voltage difference Vtop−Vthr is determined to be higher than the predetermined threshold Vth, the processing proceeds to step 602 and the vehicle controller 11 determines that the power transmitting coil 20 is off to the side of the sub-coil with the highest voltage Vtop (Posi=1). Meanwhile, when the voltage difference Vtop−Vthr is determined to be equal to or lower than the predetermined threshold Vth in step S603, the processing proceeds to step S604 and the vehicle controller 11 determines that the coil is off to the side of the sub-coil with the third highest voltage Vthr (referred to as “Posi=2”).
In step S605, the vehicle controller 11 determines whether the voltage V2 is equal to or lower than the zero determination threshold V0. When the voltage V2 is determined to be equal to or lower than the zero determination threshold V0 (determined to be zero), the processing proceeds to step S606 and the vehicle controller 11 determines whether the determination result in step S602 is “Posi=1.” The processing proceeds to step S607 when the determination result is “Posi=1” and proceeds to step S611 when the determination result is “Posi=2.” In step S607, the processing proceeds to step S608 when the voltage V1 is the highest voltage Vtop and proceeds to step S611 when the voltage V1 is not the highest voltage Vtop.
When the voltage V2 is determined to be higher than the zero determination threshold V0 (in other words, the voltage V4 is determined to be equal to or lower than the zero determination threshold V0) (determined to be zero) in step S605, the processing proceeds to step S609. In step S609, the processing proceeds to step S610 when the determination result is “Posi=1” and proceeds to step S608 when the determination result is “Posi=2.” In step S610, the processing proceeds to step S611 when the voltage V5 is the highest voltage Vtop and proceeds to step S608 when the voltage V5 is not the highest voltage Vtop.
In step S608, since the power transmitting coil 20 is off to the left as viewed in the traveling direction of the vehicle 1, the output unit 15 notifies the user to steer to the left. In step S611, since the power transmitting coil 20 is off to the right as viewed in the traveling direction of the vehicle 1, the output unit 15 notifies the user to steer to the right.
As described above, in the second embodiment of the present invention, five or more sub-coils 31 to 35 are used to detect the magnetic flux in the height direction, and the vehicle controller 11 detects the misalignment, based on the magnetic flux detected by the five or more sub-coils 31 to 35. This enables detection of not only the presence or absence of misalignment but also the direction of the misalignment.
Moreover, at least five sub-coils 31 to 35 are arranged in the vehicle width direction to detect the misalignment. This enables detection of the direction of the misalignment in the vehicle width direction. Moreover, the sub coils 31 to 35 are aligned in the vehicle width direction at positions on the front side or the rear side of the vehicle 1 relative to the center of the power receiving coil 10 in the vehicle 1 below the power receiving coil 10. This enables early detection of the misalignment in the vehicle width direction when the vehicle 1 enters the parking position from the side where the sub-coils 31 to 35 are arranged.
Although the embodiments of the present invention are described above, it should not be understood that the description and drawings forming part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples, and operations techniques will be found by those skilled in the art.
For example, in the first and second embodiments of the present invention, description is given of the case of using the three sub coils 31 to 33, the combination of sub-coils 31, 33 and the power receiving coil 10, or the five sub-coils 31 to 35. However, the parking assistance device may use four, six or more sub-coils or a combination of these sub-coils and the power receiving coil to detect the magnetic flux in the height direction, and detect the presence or absence of the misalignment and the direction of the misalignment, based on the decrease of the magnetic flux in the height direction. Using more coils for detection enables more accurate detection of the presence or absence of the misalignment and the direction of the misalignment.
Moreover, in the first and second embodiments of the present invention, description is given of the case where the three sub coils 31 to 33, the combination of sub-coils 31, 33 and the power receiving coil 10, or the five sub-coils 31 to 35 are arranged in a row in the vehicle width direction. However, the alignment direction of the coils is not limited particularly to the vehicle width direction. For example, misalignment in the traveling direction of the vehicle 1 can be detected by arranging multiple sub-coils in a row in the traveling direction of the vehicle 1. Moreover, the misalignment in both of the vehicle width direction and the traveling direction of the vehicle 1 can be detected by arranging multiple coils in the vehicle width direction and the traveling direction of the vehicle 1.
In the first and second embodiments of the present invention, the battery 13 is described as an example of an electric load. However, the electric load in the present invention is not limited to this and may be, for example, an electric motor.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2015/052509 | 1/29/2015 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2016/121050 | 8/4/2016 | WO | A |
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