JP2012206580A - Parking assistance device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate introduction of positioning when a vehicle equipped with a power receiving coil is in a position away from a feeding coil installed in a parking area, and to increase positioning accuracy when the power receiving coil gets close to the feeding coil along with the movement of the vehicle.SOLUTION: In the parking assistance device 100, an image processing section 105 calculates differences (a distance and an angle) between the present position of the power receiving coil and a position of a feeding coil marker existing in an image after distortion correction processing and after viewpoint conversion processing, and a path calculation section 109 calculates a preferred path from the power receiving coil to the feeding coil marker on the basis of the differences. The image processing section 105 calculates the differences by using first, second and third markers, in which the number of dots is gradually increased as the power receiving coil gets closer to the feeding coil, while switching the markers in sequence along with the movement of the vehicle 10.

Description

  The present invention relates to a parking assist device, and more particularly, to a parking assist device mounted on a vehicle that charges a storage battery mounted on the vehicle from a power source (external power source) outside the vehicle by non-contact charging using electromagnetic induction. About.

  In recent years, a charging system for charging a storage battery mounted on a vehicle by non-contact charging using electromagnetic induction from an external power source has been proposed. For example, by supplying electric energy from an external power source to a power feeding coil installed in a parking area of a parking lot, electric power is generated by electromagnetic induction in a power receiving coil installed in a vehicle, and the electric energy from the power receiving coil is stored in a storage battery. A charging system that accumulates and charges the battery has been proposed. In such a charging system, in order to efficiently transmit electric energy from the power feeding coil to the power receiving coil, it is desirable to arrange the power receiving coil so as to face the power feeding coil.

  However, since the power receiving coil is normally invisible to the vehicle user and is installed on the bottom surface of the vehicle, the vehicle user operates and parks the vehicle so that the power receiving coil faces the power feeding coil. Is difficult.

  Therefore, as a conventional parking assistance device, a composite image of a parking area including a power feeding coil is generated from image data around the vehicle, and the composite image and a power receiving coil position image indicating the position of the power receiving coil are displayed on the display. The positional relationship between the power feeding coil and the power receiving coil is specified based on the power receiving efficiency, and the display position of the power receiving coil position image is determined based on the specified positional relationship (see Patent Document 1).

JP 2010-234878 A

  However, in the conventional parking assist device, the positional relationship between the power feeding coil and the power receiving coil is specified based on the power receiving efficiency of the power receiving coil. Therefore, the power receiving efficiency can be obtained unless the power receiving coil is close to the power feeding coil. It is impossible to provide parking assistance. For example, in the conventional parking assistance device, parking assistance cannot be performed when the vehicle is outside the parking area and is away from the power feeding coil.

  The present invention has been made in view of such a point, and facilitates introduction of alignment when a vehicle including a power receiving coil is located away from a power feeding coil installed in a parking area, and movement of the vehicle. Accordingly, an object of the present invention is to provide a parking assist device that can improve the alignment accuracy when the power receiving coil comes close to the power feeding coil.

  A parking assistance device according to the present invention is a parking assistance device used for alignment of a power receiving coil installed on the bottom surface of a vehicle and a power feeding coil installed on the ground, wherein the current position of the power receiving coil and the vehicle An image processing unit that calculates a difference from a position of a feeding coil marker present in an image captured by an installed camera, and a preferable path from the receiving coil to the feeding coil marker is calculated based on the difference. A path calculation unit, and the image processing unit uses a plurality of feeding coil markers that gradually increase as the number of dots approaches the feeding coil, and sequentially uses the difference as the vehicle moves. Use a configuration to calculate.

  According to the present invention, it is easy to introduce alignment when a vehicle including a power receiving coil is located away from a power feeding coil installed in a parking area, and the power receiving coil becomes a power feeding coil as the vehicle moves. When close to each other, the alignment accuracy can be increased.

The block diagram which shows the structure of the parking assistance apparatus which concerns on one embodiment of this invention. The figure which shows the positional relationship of the receiving coil and electric power feeding coil which concern on one embodiment of this invention The figure which shows the relationship between the steering angle of the vehicle which concerns on one embodiment of this invention, and the turning radius of a vehicle Guide display example according to one embodiment of the present invention Guide display example according to one embodiment of the present invention Example of feeding coil marker according to one embodiment of the present invention Example of feeding coil marker according to one embodiment of the present invention

  Hereinafter, a parking assistance apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a parking assistance apparatus 100 according to the present embodiment.

  As shown in FIG. 1, the parking assistance device 100 is mounted on a vehicle 10. The parking assistance apparatus 100 includes a reference position storage unit 101, an A / D conversion unit 103, an image processing unit 105, a D / A conversion unit 107, a route calculation unit 109, and an image data storage unit 111. Note that the camera 11, the display unit 13, the vehicle speed detection unit 15, and the steering detection unit 17 may be provided in advance in the vehicle 10 or may be provided in the parking assistance device 100.

  The camera 11 is installed at the rear part of the vehicle 10 and takes an image of the vicinity of the rear part of the vehicle 10 including an image of a power feeding coil installed on the ground in the parking area of the parking lot, and A / D converts an analog image signal. Output to the unit 103. The camera 11 is installed in the vehicle 10 under such mounting conditions that a part of the vehicle 10 (such as a rear bumper) is reflected in the shooting range. For example, the shift lever provided in the vehicle 10 is in the reverse position. Take a picture at some time. In addition, a marker (feed coil marker) indicating the position is marked on the feed coil.

  The A / D conversion unit 103 converts an analog image signal into digital image data and outputs the digital image data to the image processing unit 105.

  The reference position storage unit 101 stores the current position of the power receiving coil installed on the bottom surface of the vehicle 10 in the horizontal direction of the vehicle 10 as a reference position (origin). The reference position storage unit 101 stores the horizontal center of the power receiving coil as a reference position.

  The image processing unit 105 performs a conventional distortion correction process and a conventional viewpoint conversion process on the digital image data input from the A / D conversion unit 103, and performs the distortion correction process and the viewpoint conversion process. The image data is stored in the image data storage unit 111. Further, the image processing unit 105 determines whether or not an image of the feeding coil marker exists in the image after the distortion correction process and the viewpoint conversion process. For example, the technique disclosed in Japanese Patent Laid-Open No. 05-176323 can be used as the distortion correction process, and the technique disclosed in Japanese Patent Laid-Open No. 2003-182489 can be used as the viewpoint conversion process. it can.

  The distortion caused by the photographing with the wide-angle lens of the camera 11 is corrected by the distortion correction process, and the image photographed from obliquely above the ground by the camera 11 is viewed from above (directly above) the ground by the viewpoint conversion process. Can be converted into a clear image (overhead image). Therefore, by the distortion correction process and the viewpoint conversion process, the image processing unit 105 and the route calculation unit 109 can obtain the positional relationship between the power receiving coil and the power feeding coil marker as the positional relationship on the plane (ground).

  Further, when the image of the feeding coil marker exists in the image after the distortion correction processing and the viewpoint conversion processing, the image processing unit 105 determines the difference between the current position of the receiving coil (reference position) and the position of the feeding coil marker ( Distance and angle), and the calculation result is output to the route calculation unit 109.

  In addition, the image processing unit 105 adds, to the image data stored in the image data storage unit 111 according to the calculation result in the route calculation unit 109, a preferable route (preferable travel locus) from the power receiving coil or the vehicle 10 to the feeding coil marker. ) And a predicted traveling locus by the current steering operation are generated to generate combined image data, and the digital combined image data is output to the D / A conversion unit 107. Note that the guide line can be generated by the image processing unit 105 using a conventional technique (for example, the technique disclosed in Japanese Patent Laid-Open No. 2002-251632) according to the calculation result of the path calculation unit 109. Further, the predicted traveling locus can be generated by the image processing unit 105 using a conventional technique (for example, a technique disclosed in Japanese Patent Application Laid-Open No. 2002-251632) according to the detection result of the steering detection unit 17.

  The D / A conversion unit 107 converts digital image data into an analog image signal and outputs the analog image signal to the display unit 13.

  The display unit 13 displays an image based on the analog image signal input from the D / A conversion unit 107. The display unit 13 is installed at a position where the user of the vehicle 10 can see, and displays an image when, for example, the shift lever provided in the vehicle 10 is in the reverse position. As the display unit 13, for example, a display screen included in a car navigation device mounted on the vehicle 10 can be used.

  The route calculation unit 109 calculates a preferable route (preferred travel locus) from the power receiving coil to the power feeding coil marker based on the difference (distance and angle) between the current position of the power receiving coil and the position of the power feeding coil marker. Is output to the image processing unit 105. Further, as the vehicle 10 moves, the route calculation unit 109 calculates the moving direction and moving distance of the vehicle 10 based on the steering information of the vehicle 10 and the vehicle speed of the vehicle 10, and stores the reference position according to the calculation result. The reference position stored in the unit 101 is sequentially updated. Accordingly, the reference position stored in the reference position storage unit 101 is sequentially updated to the current position of the power receiving coil as the vehicle 10 moves.

  The vehicle speed detection unit 15 detects the moving speed (vehicle speed) of the vehicle 10 and outputs the detection result to the route calculation unit 109. The vehicle speed detector 15 detects the vehicle speed based on, for example, a vehicle speed pulse generated according to the rotation of the wheel of the vehicle 10. Further, as the vehicle speed detection unit 15, for example, a vehicle speed sensor provided in a car navigation device mounted on the vehicle 10 can be used.

  The steering detection unit 17 detects the steering direction (left rotation or right rotation) of the steering of the vehicle 10 and the steering angle, and outputs the detection result to the route calculation unit 109 as steering information. This steering information is also input to the image processing unit 105 via the route calculation unit 109. As the steering detection unit 17, for example, a gyro sensor provided in a car navigation device mounted on the vehicle 10 can be used.

  Next, details of processing in the image processing unit 105 and the route calculation unit 109 will be described with reference to FIGS. The image processing unit 105 and the route calculation unit 109 operate according to the processing flow shown in the following steps.

  [Step 01: FIG. 2] The image processing unit 105 determines the difference between the current position of the receiving coil: A (the center position of the receiving coil) and the position of the feeding coil marker: C (the center position of the marker) (linear distance: X ( Straight line distance: AB), straight line distance Y (straight line distance: CB), and angle: φ) are calculated, and the calculation result (X, Y, φ) is output to the route calculation unit 109.

  [Step 02: FIG. 2] The route calculation unit 109 obtains the predicted travel locus (straight line) when the vehicle 10 is moved straight back (back) from the current position of the power receiving coil: A and the position: C of the feeding coil marker. Contact piece with circle included at one point on circumference: E is obtained.

  [Step 03: FIG. 2] The path calculation unit 109 includes the radius of the circle from which the contact piece E is obtained: R, and the contact piece E, the center of the circle: O, and the position of the feeding coil marker: C. Angle: θ (∠ EOC) is calculated.

[Step 04: FIG. 2] The route calculation unit 109 calculates the arc distance: Z2 from the radius: R and the angle: θ according to the equation (1).
Z2 = 2πR × (θ / 360 °) (1)

[Step 05: FIG. 2] The route calculation unit 109 calculates ∠ECO according to equation (2) based on the fact that ΔEOC is an isosceles triangle.
∠ECO = (180 ° −θ) / 2 Equation (2)

[Step 06: FIG. 2] The route calculation unit 109 calculates linear distances: X2 and Y2 from the linear distance: CE according to Expressions (3) and (4).
X2 = CE · sin (∠ECO) Equation (3)
Y2 = CE · cos (∠ECO) Equation (4)

[Step 07: FIG. 2] The route calculation unit 109 calculates linear distances: X1, Y1, and Z1 according to Expressions (5) to (7).
X1 = X−X2 Formula (5)
Y1 = Y−Y2 Formula (6)
Z1 = (X1 ² + Y1 ² ) ^1/2 ... Formula (7)

  In this way, it is possible to calculate a preferable path from the power receiving coil to the power feeding coil marker, which is composed of one straight line Z1 continuous from the power receiving coil and one circular arc Z2 connected to the single straight line Z1.

[Step 08: FIGS. 2 and 3] The route calculation unit 109 calculates the steering angle: γ (FIG. 3) where the turning radius of the vehicle 10: b (FIG. 3) becomes the radius: R (FIG. 2) (8). Calculate according to 3 is a length (wheelbase) between the center of the front wheel and the center of the rear wheel of the vehicle 10.
γ = tan ⁻¹ (b / a) (8)

  [Step 09] The route calculation unit 109 outputs the calculation result (Z1, Z2, γ) to the image processing unit 105.

  Then, the image processing unit 105 and the path calculation unit 109 perform the processing of steps 01 to 09 for a predetermined period (for example, for example) while the image of the feeding coil marker exists in the image after the distortion correction processing and the viewpoint conversion processing. Repeatedly at 10 msec intervals).

  On the other hand, the image processing unit 105 stops the process of step 01 when the image of the feeding coil marker does not exist in the image after the distortion correction process and the viewpoint conversion process as the vehicle 10 moves. For example, when a part of the feeding coil marker is hidden under the vehicle 10 as the vehicle 10 moves backward, the camera 11 cannot capture all of the feeding coil marker. In addition, the image of the feeding coil marker does not exist in the image after the viewpoint conversion process.

  If the calculation result (X, Y, φ) is no longer input from the image processing unit 105 to the route calculation unit 109 due to the stop of the process in step 01, the route calculation unit 109 displays the past input last. Based on the calculation result (X, Y, φ), the processes of steps 02 to 09 are continuously executed until both the linear distance Z1 and the arc distance Z2 become 0 (zero) as the vehicle 10 moves. The parking assistance for the user of the vehicle 10 is continued. Thereby, according to this Embodiment, even if a power feeding coil hides under the vehicle 10 in the middle of alignment with the power receiving coil and power feeding coil by the user of the vehicle 10, parking with respect to the user of the vehicle 10 is carried out. Since the support can be continued, the user of the vehicle 10 can reliably face the power receiving coil to the power feeding coil.

  Next, an example of parking assistance for the user of the vehicle 10 will be described with reference to FIGS. 4A and 4B. 4A and 4B are examples of images displayed on the display unit 13. Moreover, as shown in FIGS. 4A and 4B, parking assistance according to the present embodiment is performed by the first guide to the fourth guide. In each of the images of the first guide to the fourth guide, a solid guide line indicates a preferable route from the power receiving coil to the power feeding coil marker, and a dotted guide line indicates an expected travel locus by the current steering operation. In addition, the overhead image including the whole image of the vehicle 10 in the first guide to the fourth guide is installed in the vehicle 10 with a plurality of cameras that capture images of the front, rear, left and right sides of the vehicle 10, for example. It can be created using the technique disclosed in the pamphlet of International Publication No. 2000/064175.

  [First Guide: FIG. 4A] The image processing unit 105 generates a solid guide line based on the linear distance Z1 calculated in Step 07, and generates a dotted guide line based on the steering information. One guide image is generated. The route calculation unit 109 instructs the image processing unit 105 to display the first guide on the display unit 13 until the linear distance Z1 becomes 0 (zero) as the vehicle 10 moves backward. The route calculation unit 109 can calculate whether or not the linear distance Z1 is 0 (zero) based on the detection result in the vehicle speed detection unit 15 and the detection result in the steering detection unit 17. It can be judged from the distance. The image processing unit 105 generates the dotted guide lines based on the steering information in the same manner in the generation of the following second to fourth guide images. The parking assistance device 100 prompts the user of the vehicle 10 to recede the vehicle 10 straight ahead by the first guide.

  [Second Guide: FIG. 4A] The route calculation unit 109 outputs a control signal indicating that to the image processing unit 105 when the linear distance Z1 becomes 0 (zero). In response to this control signal, the image processing unit 105 generates a solid guide line based on the arc distance Z2 calculated in step 04, and steers based on the steering angle γ calculated in step 08. An image is generated to generate a second guide image. The parking assistance apparatus 100 can teach the timing of rotating the steering, the direction of rotating the steering, and the rotation angle of the steering to the user of the vehicle 10 by the second guide. The image processing unit 105 displays the second guide on the display unit 13 until the process of step 01 is stopped as the vehicle 10 moves backward.

  [Third Guide: FIG. 4B] When the vehicle 10 moves, the image processing unit 105 detects that the image of the feeding coil marker no longer exists in the image after the distortion correction process and the viewpoint conversion process. A third guide is displayed on the display unit 13 to make the deceleration of the vehicle 10 suitable for the user of the vehicle 10. The route calculation unit 109 instructs the image processing unit 105 to display the third guide on the display unit 13 until the arc distance Z2 becomes 0 (zero) as the vehicle 10 moves backward.

  [Fourth Guide: FIG. 4B] The path calculation unit 109 outputs a control signal indicating that to the image processing unit 105 when the arc distance: Z2 becomes 0 (zero). In response to this control signal, the image processing unit 105 causes the display unit 13 to display a fourth guide that makes the vehicle 10 stop in response to the user of the vehicle 10. At this time, the power receiving coil installed on the bottom surface of the vehicle 10 faces the power feeding coil installed in the parking area.

  By the first guide to the fourth guide as described above, the user of the vehicle 10 performs any steering operation, accelerator operation, and brake operation according to the movement of the vehicle 10 until the power receiving coil faces the power feeding coil. It is possible to recognize whether it should be.

  As described above, according to the present embodiment, since the image processing unit 105 and the route calculation unit 109 perform the parking support for the user of the vehicle 10 by the processing of steps 01 to 09, a special device such as a magnetic field sensor is used. Even if the vehicle 10 is not installed in the vehicle 10, the user of the vehicle 10 can reliably face the power receiving coil installed on the bottom surface of the vehicle 10 to the power feeding coil installed in the parking area.

  Further, according to the present embodiment, the first guide is displayed when the vehicle 10 is located away from the power supply coil, and the vehicle is switched from the first guide to the second guide when the vehicle 10 approaches the power supply coil. Since it displays, parking assistance can be performed from the time when the vehicle 10 is at a position away from the power supply coil, and the power reception coil can be reliably faced to the power supply coil.

  Next, an example of the feeding coil marker according to the present embodiment will be described with reference to FIGS. 5A and 5B. In addition, in order to avoid that description of drawing becomes complicated, description of the camera 11 shown to FIG. 5A is abbreviate | omitted in FIG. 5B.

  In the present embodiment, the first marker, the second marker, and the third marker as shown in FIG. 5A are used as the feeding coil marker. As shown in FIG. 5A, the number of dots in the first marker is smaller than the number of dots in the second marker, and the number of dots in the second marker is smaller than the number of dots in the third marker. The third marker is marked with the feeding coil centered on the other, while the second marker is marked at a position away from the feeding coil, and the first marker is marked at a position further away from the second marker. The Normally, the first marker and the second marker are marked in the parking area where the feeding coil is installed.

  Then, the image processing unit 105 switches the feeding coil marker used when performing the process of step 01 in the order of the first marker → the second marker → the third marker as the vehicle 10 moves backward.

  That is, as shown in FIG. 5B, the image processing unit 105 uses the image of the first marker in the image after the distortion correction process and the viewpoint conversion process when the vehicle 10 is located away from the feeding coil. The process of step 01 is performed. Next, when the vehicle 10 approaches the power feeding coil as the vehicle 10 moves backward, the image processing unit 105 causes the second marker when the first marker image does not exist in the image after the distortion correction process and the viewpoint conversion process. If the second marker image does not exist in the image after the distortion correction process and the viewpoint conversion process, the process of step 01 is performed using the third marker image. Do. Furthermore, the image processing unit 105 causes the vehicle 10 to be closer to the power supply coil, and the third marker image does not exist in the image after the distortion correction process and the viewpoint conversion process, that is, the image of the power supply coil marker exists. If not, the process of step 01 is stopped. As described above, the image processing unit 105 performs the process of step 01 by using a plurality of power supply coil markers whose number of dots in the marker gradually increases as the distance from the power supply coil is approached. .

  Here, in each marker, the smaller the number of dots in the marker, the larger the size and interval of each dot. Therefore, while the feed coil marker can be recognized from a greater distance, The accuracy is inferior. Conversely, the larger the number of dots in the marker, the smaller the size and interval of each dot. Therefore, the feeding coil marker cannot be recognized unless they are close to each other, but the accuracy of the position of the feeding coil marker is increased. Therefore, as described above, by switching the feeding coil marker used when performing the process of step 01 in the order of the first marker → the second marker → the third marker, Thus, the positioning accuracy is gradually increased in order of the second marker and the third marker, and the power receiving coil can be directly opposed to the power feeding coil with the smallest error by using the third marker.

  That is, according to the present embodiment, it is easy to introduce alignment when the vehicle 10 including the power receiving coil is at a position away from the power feeding coil installed in the parking area, and as the vehicle 10 moves. When the power receiving coil comes close to the power feeding coil, the alignment accuracy can be increased.

  The embodiment of the present invention has been described above.

  Note that although cases have been described with the above embodiment as examples where the present invention is configured by hardware, the present invention can also be realized by software in cooperation with hardware.

  Each functional block used in the description of the above embodiment is typically realized as an LSI which is an integrated circuit. These may be individually made into one chip, or may be made into one chip so as to include a part or all of them. The name used here is LSI, but it may also be called IC, system LSI, super LSI, or ultra LSI depending on the degree of integration.

  Further, the method of circuit integration is not limited to LSI's, and implementation using dedicated circuitry or general purpose processors is also possible. An FPGA (Field Programmable Gate Array) that can be programmed after manufacturing the LSI or a reconfigurable processor that can reconfigure the connection and setting of circuit cells inside the LSI may be used.

  Furthermore, if integrated circuit technology comes out to replace LSI's as a result of the advancement of semiconductor technology or a derivative other technology, it is naturally also possible to carry out function block integration using this technology. Biotechnology can be applied.

  INDUSTRIAL APPLICABILITY The present invention is suitable for a parking assistance device or the like mounted on a vehicle that charges a storage battery mounted on the vehicle from a power source (external power source) outside the vehicle by non-contact charging using electromagnetic induction.

DESCRIPTION OF SYMBOLS 10 Vehicle 11 Camera 13 Display part 15 Vehicle speed detection part 17 Steering detection part 100 Parking assistance apparatus 101 Reference position storage part 103 A / D conversion part 105 Image processing part 107 D / A conversion part 109 Path | route calculation part 111 Image data storage part

Claims (2)

A parking assistance device used for alignment of a power receiving coil installed on the bottom surface of a vehicle and a power feeding coil installed on the ground,
An image processing unit for calculating a difference between a current position of the power receiving coil and a position of a power feeding coil marker present in an image photographed by a camera installed in the vehicle;
A path calculating unit that calculates a preferable path from the power receiving coil to the power feeding coil marker based on the difference, and
The image processing unit calculates the difference by sequentially switching and using a plurality of feeding coil markers that increase in number as the number of dots approaches the feeding coil as the vehicle moves.
Parking assistance device. The path calculation unit calculates the preferable path including one straight line connected to the power receiving coil and one arc connected to the one straight line.
The parking assistance device according to claim 1.