Patent Publication Number: US-2023158911-A1

Title: Parking assist apparatus

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a parking assist apparatus capable of charging a vehicle battery by receiving power from power supply equipment arranged externally to a vehicle. 
     2. Description of the Related Art 
     Hitherto, there has been known a parking assist apparatus which photographs a road surface around a vehicle by using a camera mounted on the vehicle, detects positions of a parking space and a power transmission unit installed in the parking space by performing image processing on the taken images, and moves the vehicle based on results of the detection so that a position of a power receiving unit of the vehicle and the position of the power transmission unit of the parking space match (so that deviation is reduced). 
     The parking assist apparatus as disclosed in Japanese Patent Application Laid-open No. 2017-138664 is configured to photograph the parking space and a road surface in the vicinity of the parking space by using a camera mounted on the vehicle, and detect a target parking position by converting coordinates (coordinates of pixels) in the image of an image of the power transmission unit included in the taken images to coordinates in real space. Further, the parking assist apparatus as disclosed in WO 2011/132271 A1 is configured to photograph a light emitting portion arranged in a power transmission unit by using a camera, detect the position and orientation of the light emitting portion by using image recognition, detect a positional relationship between the power transmission unit and the vehicle based on results of the detection, and guide the vehicle to the power transmission unit by controlling the steering of the vehicle based on a result of the detection of the positional relationship between the power transmission unit and the vehicle. 
     However, in the related-art method of identifying the position of the power transmission unit from an image taken by the camera, the external appearance shape of the power transmission unit is unknown, and hence there may be cases in which the power transmission unit or the position of the power transmission unit is not identifiable from the taken image. When the position of the power transmission unit is not accurately identifiable, it is not possible to align each of the position of the power transmission unit and the position of the power receiving unit of the vehicle with a position suitable for charging. This may consequently cause a decrease in charging efficiency or improper charging when power is wirelessly supplied in the parking space. 
     SUMMARY OF THE INVENTION 
     The present invention has been made in order to address the above-mentioned problem. That is, one object of the present invention is to provide a parking assist apparatus capable of parking a vehicle at a position suitable for charging with respect to a power transmission unit. 
     According to at least one embodiment of the present invention, there is provided a parking assist apparatus ( 20 ), the parking assist apparatus ( 20 ) being mounted on a vehicle ( 10 ) including a power receiving unit ( 224 ) configured to receive power from a power supply device ( 90 ) including a power transmission unit ( 92 ), the parking assist apparatus ( 20 ) being configured to execute parking assist for parking the vehicle ( 10 ) in a parking space, the parking assist apparatus ( 20 ) including: a wireless communication device ( 223 ) configured to perform wireless communication to and from the power supply device ( 90 ); an image pickup device ( 210 ,  211 ,  212 ,  213 ) configured to photograph a peripheral region of the vehicle ( 10 ); and a control device ( 201 ) configured to search for a parking space (PS) present in the peripheral region of the vehicle ( 10 ) from an image of the peripheral region of the vehicle ( 10 ) taken by the image pickup device ( 210 ,  211 ,  212 ,  213 ), set a target parking area (TA) in the parking space (PS) detected by the search, and assist parking of the vehicle ( 10 ) in the target parking area (TA). The control device ( 201 ) has external appearance information, which is information relating to a feature of an external appearance of each of a plurality of the power transmission units ( 92 ), registered therein in association with identification information on the power supply device ( 90 ). The control device ( 201 ) is configured to, when the control device ( 201 ) sets the target parking area (TA) in the detected parking space (PS): acquire the identification information transmitted from the power supply device ( 90 ) installed in the parking space via the wireless communication device ( 223 ); search for the power transmission unit ( 92 ) included in the image of the peripheral region of the vehicle ( 10 ) by using the external appearance information corresponding to the acquired identification information; identify a position of the power transmission unit ( 92 ) detected by the search; and set a position of the target parking area (TA) so that a position of the power receiving unit ( 224 ) matches the position of the power transmission unit ( 92 ) in a top view. 
     According to the at least one embodiment of the present invention, the external appearance information corresponding to the identification information on the power supply device is used to search for the power transmission unit. With this configuration, it is possible to search for the power transmission unit which matches the external appearance information. Further, the position of the power transmission unit detected by the search can be accurately identified. Therefore, by setting the position of the target parking area so that the identified position of the power transmission unit and the position of the power receiving unit of the vehicle match in a top view, the target parking area can be set at a position suitable for charging. As a result, the vehicle can be parked in a position suitable for charging with respect to the power transmission unit. Moreover, according to the at least one embodiment of the present invention, it is possible to reduce the processing load on the control device. For example, with a method in which pieces of external appearance information on various power transmission units are registered in advance in the control device, and the power transmission unit is searched for in an exhaustive manner by using those plurality of pieces of external appearance information, processing of “searching for the power transmission unit by using a piece of external appearance information” is required to be executed repeatedly for each piece of external appearance information. In contrast, according to the at least one embodiment of the present invention, through use of the external appearance information corresponding to the identification information acquired by wireless communication, the power transmission unit can be searched for by using only the external appearance information indicated by the acquired identification information, and it is not required to perform an exhaustive search. Consequently, the processing load on the control device is reduced as compared with the method of searching for the power transmission unit in an exhaustive manner by using a plurality of pieces of external appearance information. 
     In one aspect of the present invention, the identification information is information indicating a manufacturer of the power supply device. 
     With the above-mentioned configuration, even when the external shape (external appearance) of the power transmission unit is different for each manufacturer, the power transmission unit can be searched for and the position of the power transmission unit can be identified. 
     In one aspect of the present invention, the power receiving unit ( 224 ) includes a power receiving coil ( 225 ) configured to receive supply of power in a non-contact manner from the power transmission unit ( 92 ) including a power transmission coil ( 93 ). 
     In the method of transmitting power from the power transmission unit to the power receiving unit in a non-contact manner, when the misalignment between the power transmission coil of the power transmission unit and the power receiving coil of the power receiving unit becomes smaller, the efficiency of power transmission becomes higher. Therefore, with the above-mentioned configuration, the efficiency of power transmission from the power transmission unit of the power supply device to the power receiving unit of the vehicle can be increased. 
     In the above description, the terms and/or reference symbols used in at least one embodiment described later are enclosed in parentheses and assigned to the components of the present invention corresponding to the at least one embodiment for easier understanding of the present invention. However, the constituent elements of the present invention are not limited to the at least one embodiment defined by the terms and/or reference symbols. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a diagram for illustrating a parking assist apparatus according to at least one embodiment of the present invention. 
         FIG.  2 A  is a diagram for illustrating a positional relationship between a parking space and a target parking area. 
         FIG.  2 B  is a diagram for illustrating a positional relationship between a parking space and a target parking area. 
         FIG.  3 A  is a flowchart for illustrating a parking assist routine to be executed by a CPU. 
         FIG.  3 B  is a flowchart for illustrating a parking assist routine to be executed by the CPU. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     At least one embodiment of the present invention is now described. In the following description, a parking assist apparatus for a vehicle may be abbreviated as “assist apparatus.” Further, “parking space” in the following description means a space partitioned so that one vehicle can park. 
       FIG.  1    is a schematic diagram for illustrating a configuration example of a vehicle  10 , an assist apparatus  20  mounted on the vehicle  10 , and a wireless power supply device  90  that can transmit power (can transmit electrical power) to the vehicle  10  in a non-contact manner. The vehicle  10  in the at least one embodiment is an electric vehicle (electric automobile), which includes a traction motor (not shown) and a battery  11 . The traction motor is a driving force source for traveling. The battery  11  is a power source for in-vehicle devices including the traction motor. The assist apparatus  20  is configured such that power can be received (transmission of electrical power can be received) from the wireless power supply device  90  installed in a parking space PS in a non-contact manner to charge the battery  11 . 
     The wireless power supply device  90  is configured to transmit power to the assist apparatus  20  in a non-contact manner. The wireless power supply device  90  includes a power transmission unit  92  including a power transmission coil  93 , and a wireless communication device  91  capable of wireless communication to and from a wireless communication device  223  mounted on the vehicle  10 . To distinguish between the wireless communication device  223  and the wireless communication device  91 , the wireless communication device  223  mounted on the vehicle  10  is hereinafter referred to as “in-vehicle communication device  223 ,” and the wireless communication device  91  of the wireless power supply device  90  installed in the parking space PS is referred to as “equipment communication device  91 .” The power transmission unit  92  is installed at a predetermined position on a road surface of the parking space PS so that the power transmission unit  92  is located at a lower position than the vehicle  10  when the vehicle  10  is parked in the parking space PS. The configuration of the wireless power supply device  90  is not particularly limited, and a configuration publicly known in the related art can be applied. 
     As illustrated in  FIG.  1   , the assist apparatus  20  includes a vehicle control ECU  201 , a power management ECU (hereinafter referred to as “PM ECU  202 ”), an electric power steering ECU (hereinafter referred to as “EPS ECU  203 ”), a shift-by-wire ECU (hereinafter referred to as “SBW ECU  204 ”), a brake ECU  205 , a communication ECU  206 , a charging ECU  207 , and a human machine interface (HMI)  208 . Each ECU includes a microcomputer. The microcomputer includes, for example, a CPU, a ROM, a RAM, a readable and writable non-volatile memory, and an interface. The CPU implements various functions by executing instructions (programs and routines) stored in the ROM. The ECUs and the HMI  208  are connected to each other so that data is exchangeable (communicable) via a controller area network (CAN). Therefore, detection results obtained by sensors connected to a certain ECU and operations to switches, for example, can be acquired by an ECU other than the certain ECU. 
     The vehicle control ECU  201  is a central electronic control unit which assists the driver with parking. The vehicle control ECU  201  is an example of a control device in the present invention, and executes parking assist control described later. A plurality of cameras  210 ,  211 ,  212 , and  213 , a plurality of sonar sensors  214 , and a parking assist switch  215  are connected to the vehicle control ECU  201 . In  FIG.  1   , one sonar sensor  214  is illustrated for simplification. 
     The plurality of cameras  210 ,  211 ,  212 , and  213  are an example of an image pickup device in the present invention. The plurality of cameras  210 ,  211 ,  212 , and  213  generate image data by photographing the landscape of the region around the vehicle  10  (the landscape outside the vehicle). The plurality of cameras  210 ,  211 ,  212 , and  213  include a front camera  210 , a rear camera  211 , a right-side camera  212 , and a left-side camera  213 . The front camera  210  is arranged, for example, in a substantially central portion of a front bumper in a vehicle width direction, and generates image data by photographing a landscape including the road surface in front of the vehicle  10 . The rear camera  211  is arranged, for example, on a wall portion of a rear trunk at the rear of the vehicle  10 , and generates image data by photographing a landscape including the road surface behind the vehicle  10 . The right-side camera  212  is arranged, for example, on a right side-view mirror, and generates image data by photographing a landscape including the road surface on the right side of the vehicle  10 . The left-side camera  213  is arranged, for example, on a left side-view mirror, and generates image data by photographing a landscape including the road surface on the left side of the vehicle  10 . Each of the cameras  210 ,  211 ,  212 , and  213  continuously transmits the generated image data to the vehicle control ECU  201 . 
     Each sonar sensor  214  is a well-known sensor which uses ultrasonic waves. Each sonar sensor  214  emits ultrasonic waves in a predetermined range around the vehicle  10  and receives reflected waves reflected by an object. Each sonar sensor  214  detects the presence or absence of a three-dimensional object and the distance to the three-dimensional object based on a period of time from the transmission to the reception of the ultrasonic waves, and continuously transmits the detection result to the vehicle control ECU  201 . 
     The parking assist switch  215  is a switch which can be operated by an occupant of the vehicle  10  (user of the vehicle  10 ). The parking assist switch  215  is arranged at a position at which the occupant (driver) sitting in a driver&#39;s seat of the vehicle  10  can operate the parking assist switch  215 . The vehicle control ECU  201  can detect an operation on the parking assist switch  215 . 
     In addition, a vehicle speed sensor (not shown) is connected to the vehicle control ECU  201 . The vehicle speed sensor detects the vehicle speed, and continuously outputs a signal indicating the detected vehicle speed to the vehicle control ECU  201 . 
     The PM ECU  202  is an electronic control unit for controlling a driving force generated by the traction motor. A traction motor driver  216  and an accelerator pedal sensor  217  are connected to the PM ECU  202 . The traction motor driver  216  drives the traction motor. The traction motor driver  216  is, for example, an inverter. The accelerator pedal sensor  217  detects an operation amount of an accelerator pedal (not shown), and transmits the detection result to the PM ECU  202 . The PM ECU  202  sets a target driving force in accordance with the operation amount of the accelerator pedal detected by the accelerator pedal sensor  217 , and controls the traction motor driver  216  so that the target driving force is generated. 
     The vehicle control ECU  201  can transmit a drive command (a signal for controlling the driving force, for example, a signal indicating a target travel speed) to the PM ECU  202 . When the PM ECU  202  receives the drive command from the vehicle control ECU  201 , the PM ECU  202  controls the traction motor driver  216  so that the vehicle  10  travels at the travel speed indicated by the drive command. Therefore, the PM ECU  202  can automatically drive the traction motor (that is, without requiring the driver to operate the accelerator pedal) in accordance with the drive command received from the vehicle control ECU  201 . 
     The EPS ECU  203  is an electronic control unit of a well-known electric power steering system. The EPS ECU  203  is connected to a steering motor driver  218  and a steering angle sensor  219 . The steering motor driver  218  can change a steering angle (also referred to as “steered angle” or “steer angle”) of the vehicle  10  by controlling a steering motor (not shown). The steering angle sensor  219  is configured to detect the steering angle of a steering wheel of the vehicle  10 , and output a signal indicating the steering angle. The EPS ECU  203  applies a steering torque (steering assist torque) to a steering mechanism (not shown) by controlling the steering motor driver  218  based on the signal output from the steering angle sensor  219  and the vehicle speed and driving the steering motor, thereby assisting the steering operation by the driver. 
     The vehicle control ECU  201  can transmit a steering command (a signal for controlling the steering angle of the vehicle  10 , for example, a signal including a target steering angle) to the EPS ECU  203 . When the EPS ECU  203  receives the steering command from the vehicle control ECU  201 , the EPS ECU  203  controls the steering motor driver  218  in accordance with the received steering command. Therefore, the vehicle control ECU  201  can automatically change the steering angle of steered wheels of the vehicle  10  (that is, without requiring a steering operation by the driver) via the EPS ECU  203 . 
     The SBW ECU  204  is connected to a shift position sensor  220 . The shift position sensor  220  detects a position of a shift lever, which is an operating member that can be operated by the driver. The positions of the shift lever include a parking position (P), a forward drive position (D), and a reverse position (R). The SBW ECU  204  receives the position of the shift lever from the shift position sensor  220 , and switches a shift range of a transmission (not shown) of the vehicle  10  based on the position (that is, performs shift control of the vehicle  10 ). 
     The vehicle control ECU  201  can transmit a shift change command (a signal for switching the shift range of the transmission, for example, a signal including the shift range after switching) to the SBW ECU  204 . When the SBW ECU  204  receives the shift change command from the vehicle control ECU  201 , the SBW ECU  204  performs control to switch the shift range of the transmission in accordance with the received shift change command. Therefore, the vehicle control ECU  201  can automatically change the shift range of the transmission of the vehicle  10  (that is, without requiring the driver to operate the shift lever) via the SBW ECU  204 . 
     The brake ECU  205  is connected to a brake actuator  221  and a brake pedal sensor  222 . The brake pedal sensor  222  is configured to detect an operation amount of a brake pedal (not shown). The brake ECU  205  applies to the wheels a braking force in accordance with the operation amount of the brake pedal by operating the brake actuator  221  in accordance with the detection result of the operation amount of the brake pedal acquired from the brake pedal sensor  222 . 
     The vehicle control ECU  201  can transmit a braking command (a signal for controlling the braking force, for example, a signal including a target braking force) to the brake ECU  205 . When the brake ECU  205  receives the braking command from the vehicle control ECU  201 , the brake ECU  205  controls the brake actuator  221  in accordance with the received braking command. Therefore, the brake ECU  205  can automatically control the braking force of the vehicle  10  (that is, without requiring the driver to operate the brake pedal) by controlling the brake actuator  221 . 
     The in-vehicle communication device  223  (wireless communication device) is connected to the communication ECU  206 . The in-vehicle communication device  223  can perform wireless communication to and from the wireless communication device (equipment communication device  91 ) of the wireless power supply device  90 . The in-vehicle communication device  223  and the equipment communication device  91  each include a communication circuit compliant with a wireless LAN standard or a wireless PAN standard, such as the Institute of Electrical and Electronic Engineers (IEEE) 802.11 series (sometimes referred to as “Wi-Fi” (“Wi-Fi” is a trademark of the Wi-Fi Alliance)), or the IEEE 802.15 series. Further, the in-vehicle communication device  223  and the equipment communication device  91  each include, in addition to such communication circuits, a communication circuit capable of wireless communication based on a communication method (communication standard) different from that of those communication circuits. For example, the in-vehicle communication device  223  and the equipment communication device  91  each include a communication circuit which uses long waves (low frequency (LF), or longwave or long wave (LW); radio waves having a frequency of from 30 kHz to 300 kHz) for communication, a communication circuit which uses radio frequencies (RF) for communication, and a communication circuit of an ultra-wideband (UWB) wireless system. Further, the in-vehicle communication device  223  and the equipment communication device  91  may each include a communication circuit compliant with a short-range wireless communication standard, such as dedicated short-range communications (DSRC) or radio frequency identifier (RFID). The in-vehicle communication device  223  and the equipment communication device  91  are configured to enable wireless communication to and from each other by each of at least two types of communication methods (communication standards) different from each other. For example, the in-vehicle communication device  223  and the equipment communication device  91  each include a plurality of communication circuits capable of wireless communication using different communication methods. Further, one of the in-vehicle communication device  223  and the equipment communication device  91  may include a tag (an information recording medium that reads and writes data in a non-contact manner by using radio waves (electromagnetic waves)), and the other may include a reader that reads out data from the tag in a non-contact manner. The in-vehicle communication device  223  performs wireless communication to and from the equipment communication device  91  under the control by the communication ECU  206 . The communication ECU  206  transmits and receives various types of information to be used for a power receiving unit  224  to receive power from the wireless power supply device  90  in a non-contact manner by using the wireless communication to and from the wireless power supply device  90 . 
     The charging ECU  207  controls the charging of the battery  11 . The power receiving unit  224  is connected to the charging ECU  207 . The power receiving unit  224  includes a power receiving coil  225  and a charging circuit  226 . The power receiving coil  225  is configured to receive the supply of power from the power transmission coil  93  of the wireless power supply device  90  in a non-contact manner. The charging circuit  226  charges the battery  11  with the power received by the power receiving coil  225  under the control of the charging ECU  207 . The power receiving coil  225  is installed on a bottom surface of a vehicle body (for example, a lower surface of a floor panel). 
     The HMI  208  is arranged at a place at which the driver of the vehicle  10  can see and operate the HMI  208 . The HMI  208  includes a touch panel display  209  which can display images and receive touch operations. The vehicle control ECU  201  can display various images on the touch panel display  209  of the HMI  208  and can detect an operation on the touch panel display  209 . 
     (Parking Assist Control) 
     Next, parking assist control to be executed by the assist apparatus  20  is described. The parking assist control is control for setting a target parking area TA in the parking space PS and assisting the parking of the vehicle  10  in the set target parking area TA. The parking assist apparatus  20  according to the at least one embodiment moves the vehicle  10  to the target parking area TA without requiring the driver to operate the accelerator pedal, the brake pedal, or the steering wheel to assist the parking of the vehicle  10  in the target parking area TA. As described above, the parking space PS is a space partitioned so that one vehicle can park. More specifically, the parking space PS is a space in which the dimension in the front-rear direction and the dimension in the width direction are larger than the dimension in the front-rear direction and the dimension in the width direction of the vehicle  10  in a top view. The target parking area TA is the area in which the vehicle  10  is to actually be parked in the parking space PS (area in which the vehicle  10  fits), and is an area having substantially the same shape and dimensions as those of the vehicle  10  in a top view. 
     (Detection (Recognition) of Parking Space) 
     The vehicle control ECU  201  searches for the parking space PS present in the peripheral region of the vehicle  10  by using the image data acquired from each of the cameras  210 ,  211 ,  212 , and  213 . Specifically, the vehicle control ECU  201  first extracts a plurality of feature points included in the image data acquired from each of the cameras  210 ,  211 ,  212 , and  213 . Each feature point is a minute region in which a change in brightness is equal to or more than a threshold value (in other words, a region in which the brightness changes abruptly). Further, the vehicle control ECU  201  acquires gradation information on areas including the detected feature points. Specifically, the vehicle control ECU  201  sets a square area having a predetermined length on each side centered on one acquired feature point as a feature area corresponding to the one feature point, and divides the set feature area into a plurality of divided areas (specifically, 25 squares arranged in a matrix of 5 rows by 5 columns). Then, the vehicle control ECU  201  acquires the brightness of each divided area, and calculates, for each divided area, a “difference from an average brightness (that is, an average value of the brightness of all the divided areas) (=(brightness of each divided area)−(average value of brightness of all divided areas)).” The vehicle control ECU  201  acquires the calculated difference as gradation information indicating a trend in the level of the brightness in each feature area. Then, the vehicle control ECU  201  stores information including the position information on each detected feature point and the gradation information on each feature area corresponding to each feature point in the non-volatile memory in association with ID information for identifying the feature point as information relating to each feature point (hereinafter referred to as “feature point information”). 
     Then, the vehicle control ECU  201  converts the feature point information into coordinates in a real coordinate system (coordinate system indicating a position in real space based on a predetermined position of the vehicle  10  as a reference (coordinate origin)) by applying distortion correction to the coordinates of each feature point on the image (that is, the positions of the pixels corresponding to each feature point on the image). Further, the vehicle control ECU  201  detects the parking space PS by using the feature point information included in the image. For example, the vehicle control ECU  201  detects white lines drawn on the road surface by linearly approximating rows of feature points included in the image (that is, edges included in the image), and detects the region between two detected parallel white lines as the parking space PS. As the method of detecting the parking space PS, various publicly known methods can be applied. For example, the methods as described in Japanese Patent Application Laid-open No. 2007-290558 and Japanese Patent Application Laid-open No. 2008-201178 can be applied. 
     (Identification of Position of Power Transmission Unit) 
     The communication ECU  206  continuously searches for a wireless power supply device  90  (equipment communication device  91 ) capable of wireless communication present in the peripheral region of the vehicle  10  by using one of a plurality of communication methods (communication standards). When a wireless power supply device  90  capable of wireless communication is detected, the communication ECU  206  establishes wireless communication to and from the equipment communication device  91  of the detected wireless power supply device  90 . For convenience of description, the communication method is referred to as “first communication method.” For example, a communication method (communication standard) compliant with the IEEE 11 series is applied to the first communication method. When wireless communication based on the first communication method is established between the in-vehicle communication device  223  and the equipment communication device  91 , the vehicle control ECU  201  acquires identification information transmitted from the wireless power supply device  90  (information indicating the manufacturer (manufacturing company) of the wireless power supply device  90 ) by wireless communication via the in-vehicle communication device  223 . Then, the vehicle control ECU  201  uses the acquired identification information to search for an image of the power transmission unit  92  included in the image data acquired from each of the cameras  210 ,  211 ,  212 , and  213 . When an image of the power transmission unit  92  has successfully been detected by the search, the vehicle control ECU  201  identifies the position of the power transmission unit  92  in the real coordinate system based on the detection result. Specifically, the position is identified as follows. 
     In the vehicle control ECU  201 , information relating to features of the external appearance of the power transmission unit  92  of a plurality of wireless power supply devices  90  is registered in association with the information indicating the manufacturer. In the following, the “information relating to features of the external appearance of the power transmission unit  92 ” is referred to as “external appearance information,” and the data including the external appearance information is referred to as “external appearance data.” Further, “the external appearance information is registered in the vehicle control ECU  201 ” can be described as “the external appearance data is stored in the non-volatile memory of the vehicle control ECU  201  in a computer-readable format.” To the external appearance information, position information on a plurality of feature points extracted from an image of the power transmission unit  92  (for example, information indicating a relative positional relationship among feature points), and gradation information on the areas (feature areas) including the feature points can be applied. The meaning of “gradation information on the areas including the feature points” is as described above. Further, when a certain manufacturer manufactures a plurality of types of wireless power supply devices  90  having different external appearances from each other, a plurality of pieces of external appearance information are associated with the certain manufacturer. 
     The vehicle control ECU  201  reads out, from a plurality of pieces of external appearance information registered in advance, the external appearance information on the power transmission unit  92  associated with the same manufacturer as the manufacturer indicated by the identification information acquired via wireless communication. Then, the vehicle control ECU  201  uses the read external appearance information to search for an image of the power transmission unit  92  included in the image data acquired from each of the cameras  210 ,  211 ,  212 , and  213 . Specifically, the vehicle control ECU  201  searches for the image of the power transmission unit  92  included in the image data by performing pattern matching in which the read external appearance information (external appearance data) is used as a template and the image data acquired from each of the cameras  210 ,  211 ,  212 , and  213  are search images. When the vehicle control ECU  201  detects the power transmission unit  92 , the vehicle control ECU  201  confirms the position of the detected power transmission unit  92  in the real coordinate system. 
     With such a method, various power transmission units  92  having different shapes can be detected. For example, with a method of detecting (recognizing) the power transmission unit  92  installed in the parking space based on the arrangement of the feature points (edges) included in the image data acquired from each of the cameras  210 ,  211 ,  212 , and  213 , the external appearance shape of the power transmission unit installed in the parking space is unknown, and hence it is not possible to identify whether or not the detected object is a power transmission unit. Even when the detected object is a power transmission unit, it is not possible to accurately identify the external appearance shape of the power transmission unit. Further, when the power transmission unit  92  is not identifiable, in some cases, the target parking area TA is not set to the “position suitable for charging” described later. In contrast, in the at least one embodiment, the power transmission unit  92  is searched for by using external appearance data registered in the vehicle control ECU  201  in advance, and hence the external appearance shape of the power transmission unit  92  can be identified, and as a result, power transmission units  92  having various external appearances can be detected. Moreover, the position of the detected power transmission unit  92  can be accurately identified. 
     Further, according to the at least one embodiment, it is possible to reduce the processing load on the vehicle control ECU  201 . For example, with a method in which the pieces of external appearance information on the various power transmission units  92  are registered in advance in the vehicle control ECU  201 , and the image of the power transmission unit  92  is searched for in an exhaustive manner by using those plurality of pieces of external appearance information, processing of “searching for the image of the power transmission unit  92  by using one piece of external appearance information” is required to be executed repeatedly for each piece of external appearance information. In contrast, according to the at least one embodiment, through use of the external appearance information associated with the manufacturer indicated by the identification information acquired by wireless communication, the power transmission unit  92  can be searched for by using only the external appearance information associated with the manufacturer, and hence it is not required to perform an exhaustive search. 
     The vehicle control ECU  201  is configured such that additional external information can be registered. In other words, for example, the user of the vehicle  10  can additionally store the external appearance data of the power transmission unit  92  of an unregistered wireless power supply device  90  in the readable/writable non-volatile memory of the vehicle control ECU  201 . Further, when the in-vehicle communication device  223  is connected to the Internet, the vehicle control ECU  201  may access a server in which the external appearance data of the power transmission unit  92  of the wireless power supply device  90  is stored, and when the external appearance data of the power transmission unit  92  of the wireless power supply device  90  not registered in the vehicle control ECU  201  exists in the server, the vehicle control ECU  201  may download and store the external appearance data in the readable/writable non-volatile memory. In this case, it is required to prepare in advance a server in which the external appearance data of the power transmission unit  92  of the wireless power supply device  90  is stored. 
     (Setting of Target Parking Area) 
     The vehicle control ECU  201  sets the target parking area TA to a “position suitable for charging” and in an “orientation which fits well in the parking space PS.”  FIG.  2 A  and  FIG.  2 B  are schematic diagrams for illustrating an example of the “position suitable for charging” and the “orientation which fits well in the parking space PS” of the target parking area TA. Here, the “orientation which fits well in the parking space PS” can also be referred to as an orientation suitable for parking in the parking space PS. In  FIG.  2 A  and  FIG.  2 B , the front side of the vehicle  10  is indicated by an arrow Fr, the rear side of the vehicle  10  is indicated by an arrow Rr, the entrance side of the parking space PS is indicated by an arrow E, and the far side of the parking space PS is indicated by an arrow B. When wireless charging by the wireless power supply device  90  is executed, the efficiency of power transmission becomes higher as the deviation between the position of the power transmission coil  93  of the wireless power supply device  90  installed in the parking space PS and the position of the power receiving coil  225  installed in the vehicle  10  in a top view becomes smaller. Thus, in the at least one embodiment, the position at which the position of the power transmission coil  93  of the wireless power supply device  90  installed in the parking space PS and the position of the power receiving coil  225  installed in the vehicle  10  match each other in a top view (more specifically, the position at which the center of the power transmission coil  93  and the center of the power receiving coil  225  match each other in a top view) is regarded as the “position suitable for charging.” 
     Further, in the at least one embodiment, the orientation in which the front-rear direction of the vehicle  10  is parallel to the long direction of the parking space PS and the deviation between the center of the vehicle  10  in the front-rear direction and the center of the parking space PS in the long direction is small is regarded as the “orientation which fits well in the parking space PS.” In a case in which the power transmission coil  93  is installed at a position deviating from the center of the parking space PS in the long direction toward the entrance side or the far side, and a case in which the power receiving coil  225  is arranged at a position deviating from the center of the vehicle  10  in the front-rear direction toward the front side or the rear side, when the target parking area TA is set to the position suitable for charging, the center of the vehicle  10  in the front-rear direction and the center of the parking space PS in the long direction may deviate from each other. Thus, the vehicle control ECU  201  sets the orientation of the target parking area TA to the above-mentioned “orientation which fits well in the parking space PS.” For example, as illustrated in  FIG.  2 A , when the power receiving unit  224  is arranged at a position deviating from the center of the vehicle  10  toward the rear side, and the power transmission unit  92  is installed at a position deviating from the center of the parking space PS in the long direction toward the far side, the vehicle control ECU  201  sets the target parking area TA in an orientation in which the front side of the vehicle  10  is positioned at the entrance side of the parking space PS (that is, a reverse parking orientation). Meanwhile, as illustrated in  FIG.  2 B , when the power receiving unit  224  is arranged at a position deviating from the center of the vehicle  10  toward the rear side, and the power transmission unit  92  is installed at a position deviating from the center of the parking space PS in the long direction toward the entrance side, the vehicle control ECU  201  sets the target parking area TA in an orientation in which the front side of the vehicle  10  is positioned at the far side of the parking space PS (that is, a forward parking orientation). 
     In the configuration in which the power receiving coil  225  is arranged in the center of the vehicle  10  in the front-rear direction, the position suitable for charging in the target parking area TA with respect to the parking space PS is the same when the vehicle  10  faces the entrance side or the far side of the parking space PS. In order to handle such a case, in the vehicle control ECU  201 , a priority for each of forward parking (parking in the orientation in which the front side of the vehicle  10  faces the far side of the parking space PS) and reverse parking (parking in the orientation in which the front side of the vehicle  10  faces the entrance side of the parking space PS) is registered in advance. When the orientation is an “orientation which fits well in the parking space PS” regardless of whether the front side of the vehicle  10  faces the far side or the entrance side of the parking space PS, the vehicle control ECU  201  sets the orientation of the target parking area TA to the orientation having a higher priority. The priority can be changed by the user of the vehicle  10 , for example. 
     (Operation of Parking Assist Apparatus) 
     Next, operation of the assist apparatus  20  is described. Each of the cameras  210 ,  211 ,  212 , and  213  continuously executes processing of “generating image data by photographing the landscape of the peripheral region of the vehicle  10 , and transmitting the generated image data to the vehicle control ECU  201 .” The vehicle control ECU  201  continuously executes processing of extracting a plurality of feature points from the image data acquired from each of the cameras  210 ,  211 ,  212 , and  213 . 
     The communication ECU  206  continuously searches for a wireless power supply device  90  (equipment communication device  91 ) capable of wireless communication. When the communication ECU  206  detects a wireless power supply device  90  capable of wireless communication, the communication ECU  206  establishes wireless communication based on the first communication method between the in-vehicle communication device  223  and the equipment communication device  91  of the wireless power supply device  90 . When the in-vehicle communication device  223  includes a communication circuit compliant with a wireless LAN standard such as the IEEE 802.11 series, the communication ECU  206  continuously wirelessly transmits an authentication signal to the in-vehicle communication device  223 . The communication ECU  206  then waits for the in-vehicle communication device  223  to receive an authentication signal transmitted by the equipment communication device  91 . When the in-vehicle communication device  223  receives the authentication signal transmitted by the equipment communication device  91 , the vehicle control ECU  201  causes the in-vehicle communication device  223  to transmit a connection request, and waits for a connection permission signal to be transmitted from the equipment communication device  91 . When the in-vehicle communication device  223  receives the connection permission signal transmitted from the equipment communication device  91 , the vehicle control ECU  201  establishes wireless communication to and from the equipment communication device  91 . When wireless communication is established between the in-vehicle communication device  223  and the equipment communication device  91 , the vehicle control ECU  201  acquires the identification information on the wireless power supply device  90  from the wireless power supply device  90  by wireless communication. 
     The vehicle control ECU  201  may execute the processing of extracting the feature points when a predetermined condition is satisfied. Similarly, the communication ECU  206  may execute the processing for establishing wireless communication between the in-vehicle communication device  223  and the equipment communication device  91  when a predetermined condition is satisfied. For example, when the vehicle speed becomes equal to or lower than a threshold value while the vehicle  10  is traveling, the vehicle control ECU  201  determines that the predetermined condition is satisfied, starts executing the processing of extracting the plurality of feature points from the image data acquired from each of the cameras  210 ,  211 ,  212 , and  213 , and starts searching fora wireless power supply device  90  capable of wireless communication to and from the communication ECU  206 . 
     After the vehicle  10  stops, when the vehicle control ECU  201  detects an operation on the parking assist switch  215 , the vehicle control ECU  201  searches for a parking space PS which is present in the peripheral region of the vehicle  10  based on the features extracted at that time. When the vehicle control ECU  201  has successfully detected a parking space PS, the vehicle control ECU  201  identifies the position of the parking space PS in the real coordinate system. Further, when the vehicle control ECU  201  has detected the wireless power supply device  90  by the search, the vehicle control ECU  201  establishes wireless communication between the in-vehicle communication device  223  and the equipment communication device  91  of the wireless power supply device  90  as described above, and acquires the identification information from the wireless power supply device  90  via wireless communication. Moreover, the vehicle control ECU  201  reads out the external appearance information associated with the manufacturer indicated by the acquired identification information, and then uses the read external appearance information to search for the power transmission unit  92  installed in the parking space PS and identify the position of the power transmission unit  92  detected by the search. Then, the vehicle control ECU  201  sets the target parking area TA to the “position suitable for charging” and in the “orientation which fits well in the parking space PS” based on the identified position of the parking space PS and position of the power transmission unit  92 . 
     Further, the vehicle control ECU  201  displays a setting image on the touch panel display  209  of the HMI  208 . The setting image includes a plan view image, a target parking area image, a movement button image, and a confirmation button image. The plan view image is an image of the region in which the vehicle  10  is present and the peripheral region of the vehicle  10 , and is an image of the landscape of the area including the detected parking space PS as seen from directly above. The vehicle control ECU  201  generates the plan view image from the image data acquired from each of the cameras  210 ,  211 ,  212 , and  213 . The target parking area image is a quadrangular frame-shaped image showing the target parking area TA, and is an image superimposed and displayed on the plan view image. The movement button image is an image operated by the user in order to move the target parking area image. When a touch operation on the movement button image is detected, the vehicle control ECU  201  moves the target parking area image on the plan view image in accordance with the touch operation. 
     The confirmation button image is an image operated by the user in order to set (confirm) the position of the target parking area image in the plan view image as the target parking area TA. When the vehicle control ECU  201  detects a touch operation on the confirmation button image while the setting image is displayed, the vehicle control ECU  201  confirms the position and orientation of the target parking area image displayed in the parking space PS on the plan view image as the actual position and orientation of the target parking area TA with respect to the parking space PS. Further, when the vehicle control ECU  201  confirms the position and orientation of the target parking area TA, the vehicle control ECU  201  sets a target travel route TR along which the vehicle  10  is to travel in order to park the vehicle  10  in the target parking area TA. The method of setting the target travel route TR is not limited, and a publicly known method can be applied. 
     When confirmation of the target parking area TA and confirmation of the target travel route TR are complete, the vehicle control ECU  201  waits for an operation by the user to instruct movement of the vehicle  10  to be started. For example, the vehicle control ECU  201  displays a parking start button image on the touch panel display  209  of the HMI  208 . Then, when the vehicle control ECU  201  detects a touch operation on the parking start button image, the vehicle control ECU  201  starts the parking travel processing. The parking travel processing is processing of causing the vehicle  10  to travel along the set target travel route TR to the target parking area TA based on, for example, information relating to three-dimensional objects present around the vehicle  10  detected by the sonar sensor  214 , images of the peripheral regions of the vehicle  10  taken by each of the cameras  210 ,  211 ,  212 , and  213 , and the vehicle speed acquired from the vehicle speed sensor (not shown). The vehicle control ECU  201  transmits a drive command to the PM ECU  202 , a steering command to the EPS ECU  203 , and a braking command to the brake ECU  205  so that the vehicle  10  travels along the target travel route TR to the target parking area TA. 
     The communication ECU  206  uses, during the execution of the parking travel processing, another communication method different from the first communication method (the another communication method is hereinafter referred to as “second communication method”) to establish wireless communication between the in-vehicle communication device  223  and the wireless power supply device  90  (equipment communication device  91 ). As described above, when the first communication method is a communication method based on the IEEE 802.11 series, for example, a communication method compliant with a wireless LAN standard such as the IEEE 802.15 series, a communication method using long waves (LF) for communication, or a communication method of an ultra-wideband wireless system is applied to the second communication method. As the second communication method, it is preferred to apply a method having a shorter wireless communication distance than that of the first communication method. For example, when the first communication method is a communication method based on the IEEE 802.15 series, a communication method compliant with a wireless PAN standard such as the IEEE 802.15 series can be applied to the second communication method. In this case, the second communication method may be a communication method based on the wireless LAN standard, a DSRC method, or an RFID method. When the entire vehicle  10  has fit in the target parking area TA, the vehicle control ECU  201  stops the vehicle  10  and ends the parking travel processing. As a result, the parking of the vehicle  10  in the target parking area TA is complete. 
     When the parking is complete, the vehicle control ECU  201  transmits a signal instructing charging to be started to the communication ECU  206  by wireless communication based on the second communication method. When the communication ECU  206  receives the signal instructing charging to be started from the vehicle control ECU  201 , the communication ECU  206  causes the in-vehicle communication device  223  to transmit a “signal instructing charging to be started” to the equipment communication device  91  by wireless communication based on the second communication method. When the equipment communication device  91  receives the signal, the wireless power supply device  90  starts power transmission. As a result, the power receiving unit  224  receives power. The power received by the power receiving unit  224  is charged in the battery  11 . 
     After that, the vehicle control ECU  201  continuously acquires information indicating a charging rate of the battery  11  from the charging ECU  207 , and continuously determines whether or not the charging rate of the battery  11  becomes equal to or higher than a predetermined threshold value. When the charging rate of the battery  11  becomes equal to or higher than the predetermined threshold value, the vehicle control ECU  201  transmits a signal instructing charging to be ended to the communication ECU  206 . When the communication ECU  206  receives the signal instructing charging to be ended from the vehicle control ECU  201 , the communication ECU  206  causes the in-vehicle communication device  223  to transmit a “signal instructing charging to be ended” to the equipment communication device  91  by wireless communication. When the equipment communication device  91  receives the signal, the wireless power supply device  90  stops (ends) power transmission. As a result, charging of the battery  11  ends. The wireless power supply device  90  may acquire information indicating the charging rate of the battery  11  of the vehicle  10  by wireless communication, and stop power transmission based on the acquired information indicating the charging rate. 
     Next, a parking assist routine to be executed by the CPU of the vehicle control ECU  201  is described with reference to  FIG.  3 A  and  FIG.  3 B .  FIG.  3 A  and  FIG.  3 B  are flow charts for illustrating a parking assist routine to be executed by the CPU of the vehicle control ECU  201 . The routine is executed when a predetermined condition is satisfied, for example, when the vehicle speed is equal to or lower than a predetermined vehicle speed. In the following description, the CPU of the vehicle control ECU  201  is simply referred to as “CPU.” In the readable/writable non-volatile memory of the vehicle control ECU  201 , the external appearance data of the power transmission unit  92  of each of a plurality of wireless power supply devices  90  is stored in advance in association with information indicating the manufacturer of the wireless power supply device  90 . Each of the cameras  210 ,  211 ,  212 , and  213  continuously executes processing of “generating image data by photographing the landscape of the peripheral region of the vehicle  10 , and transmitting the generated image data to the vehicle control ECU  201 .” Further, during the period in which wireless communication based on the first communication method is not established between the in-vehicle communication device  223  and the equipment communication device  91 , the communication ECU  206  continues to search for a wireless power supply device  90  capable of wireless communication. When the communication ECU  206  detects a wireless power supply device  90  capable of wireless communication, the communication ECU  206  establishes wireless communication based on the first communication method to and from the wireless power supply device  90  (equipment communication device  91 ). 
     In Step S 101 , the CPU acquires image data from each of the cameras  210 ,  211 ,  212 , and  213 , extracts a plurality of feature points from the acquired image data, and stores feature point information on the extracted feature points in the RAM in association with ID information for identifying each feature point. Then, the CPU advances the process to Step S 102 . 
     In Step S 102 , the CPU determines whether or not the vehicle  10  is stopped and there has been an operation to start the setting of the target parking area TA. In the at least one embodiment, the CPU determines that there has been an operation to start the setting of the target parking area TA when there has been an operation on the parking assist switch  215 . When the vehicle  10  is stopped and there has been an operation to start the setting of the target parking area TA, the CPU advances the process to Step S 103 . When the vehicle  10  is not stopped, and when there has not been an operation to start the setting of the target parking area TA, the CPU returns the process to Step S 101 . 
     In Step S 103 , the CPU uses the feature point information on the extracted feature points to search for a parking space PS present in the peripheral region of the vehicle  10  in which the vehicle  10  can park. When a parking space PS present in the peripheral region of the vehicle  10  in which the vehicle  10  can park has successfully been detected (in other words, when the parking space PS is present), the CPU advances the process to Step S 104 . When a parking space PS present in the peripheral region of the vehicle  10  in which the vehicle  10  can park has failed to be detected, the CPU ends this parking assist routine. 
     In Step S 104 , the CPU determines whether or not wireless communication based on the first communication method is established between the equipment communication device  91  of the wireless power supply device  90  installed in the parking space PS and the in-vehicle communication device  223 . When wireless communication based on the first communication method is established between the in-vehicle communication device  223  and the equipment communication device  91 , the CPU advances the process to Step S 105 . Meanwhile, when wireless communication based on the first communication method is not established between the in-vehicle communication device  223  and the equipment communication device  91 , the CPU advances the process to Step S 116 . 
     In Step S 105 , the CPU acquires, from the wireless power supply device  90  to which wireless communication has been established, the identification information on the wireless power supply device  90  by wireless communication based on the first communication method via the in-vehicle communication device  223 . Then, the CPU advances the process to Step S 106 . 
     In Step S 106 , the CPU uses the information indicating the manufacturer of the wireless power supply device  90  represented by the identification information acquired in Step S 105  and the feature point information extracted in Step S 101  to search for the power transmission unit  92  installed in the parking space PS by, for example, pattern matching, and when the power transmission unit  92  has successfully been detected, identifies the position of the power transmission unit  92 . Specifically, first, the CPU reads out the feature data associated with the manufacturer indicated by the identification information acquired in Step S 104  from the non-volatile memory. Then, the CPU searches for the power transmission unit  92  by using the read feature data and the feature point information on the feature points of the image data stored in the RAM. When the power transmission unit  92  has successfully been detected, the CPU identifies the position of the power transmission unit  92  in the real coordinate system. 
     When the power transmission unit  92  has not successfully been detected by the above-mentioned processing, the CPU estimates the position of the power transmission unit  92  by using the feature point information on the feature points stored in the RAM. For example, when the CPU searches for a “region surrounded by feature points (region surrounded by edges)” present inside the parking space PS, and the CPU has successfully detected a “region surrounded by feature points,” the CPU estimates that the region is the power transmission unit  92 . Then, the CPU identifies the position of the estimated power transmission unit  92  in the real coordinate system. 
     Then, the CPU uses the identified position of the power transmission unit  92  in the real coordinate system (position with respect to the parking space PS) to set the target parking area TA to the “position suitable for charging” and in the “orientation which fits well in the parking space PS.” Then, the CPU advances the process to Step S 107 . 
     In Step S 107 , the CPU displays the setting image on the touch panel display  209  of the HMI  208 . As described above, the setting image includes a plan view image including the detected parking space PS and a target parking area image superimposed and displayed on the plan view image. The position and orientation of the target parking area image on the plan view image are the “position suitable for charging” and the “orientation which fits well in the parking space PS” set in Step S 106 . The CPU may superimpose and display a figure indicating the power transmission unit  92  identified in Step S 106  on the corresponding position on the plan view image. Further, the power receiving unit  224  in a case in which the vehicle  10  is parked in the target parking area TA may be superimposed and displayed on the corresponding position on the plan view image. 
     Further, in Step S 107 , the CPU displays the movement button image and the confirmation button image on the setting image, and receives operations of those button images. Then, the CPU advances the process to Step S 108 . 
     In Step S 108 , the CPU determines whether or not there has been an operation to confirm the position and orientation of the target parking area TA. For example, when the CPU detects a touch operation on the confirmation button image displayed on the setting image, the CPU determines that there has been an operation to confirm the position and orientation of the target parking area TA. The CPU repeatedly executes the processing steps of Step S 107  and Step S 108  until there is an operation to confirm the position and orientation of the target parking area TA. Further, the CPU receives touch operations on the movement button image displayed on the setting image until there is an operation to confirm the target parking area TA. When the CPU detects a touch operation on the movement button image, the CPU moves the target parking area image superimposed and displayed on the plan view image in accordance with the touch operation on the movement button image. When the CPU detects an operation to confirm the position and orientation of the target parking area TA, the CPU advances the process to Step S 109 . 
     In Step S 109 , the CPU confirms the “position and orientation of the target parking area image on the plan view image” at the time at which the “operation to confirm the position and orientation of the target parking area TA” is detected in Step S 108  as the position and orientation of the target parking area TA in the actual parking space PS. Then, the CPU sets the target travel route TR along which the vehicle  10  is to travel in order to park the vehicle  10  in the target parking area TA. Further, the CPU displays the parking start button image on the touch panel display  209  of the HMI  208 . Then, the CPU advances the process to Step S 110 . 
     In Step S 110 , the CPU determines whether or not there has been an operation to instruct the parking travel processing to be started. When an operation to instruct the parking travel processing to be started is detected, the CPU advances the process to Step S 111 . For example, when the CPU detects a touch operation on the parking start button image, the CPU determines that there has been an operation to instruct the parking travel processing to be started. When there has not been an operation to instruct the parking travel processing to be started, the CPU causes the process to wait at this step, and when the operation is performed, advances the process to Step S 111 . 
     In Step S 111 , the CPU executes the parking travel processing. Further, after execution of the parking travel processing is started, the CPU transmits a command to establish wireless communication based on the second communication method between the in-vehicle communication device  223  and the equipment communication device  91  to the communication ECU  206 . When the communication ECU  206  receives the command, the communication ECU  206  establishes wireless communication based on the second communication method between the in-vehicle communication device  223  and the equipment communication device  91 . Then, the CPU advances the process to Step S 112 . In Step S 112 , the CPU determines whether or not the parking travel processing is complete, specifically, whether or not the vehicle  10  has reached the target parking position and stopped. When the parking travel processing is not complete, the CPU continues to execute the parking travel processing until the vehicle  10  reaches the target parking position and stops. When the parking travel processing is complete, the CPU advances the process to Step S 113 . 
     In Step S 113 , the CPU transmits a signal instructing charging to be started to the communication ECU  206 . When the communication ECU  206  receives the signal instructing charging to be started from the vehicle control ECU  201 , the communication ECU  206  causes the in-vehicle communication device  223  to transmit the “signal instructing charging to be started” to the equipment communication device  91  by wireless communication based on the second communication method. As a result, power transmission by the wireless power supply device  90  is started. The power transmitted from the wireless power supply device  90  is received by the power receiving unit  224 , and the power received by the power receiving unit  224  is charged in the battery  11 . Then, the CPU advances the process to Step S 114 . 
     In Step S 114 , the CPU determines whether or not charging is complete. Specifically, the CPU continuously acquires information indicating the charging rate of the battery  11  from the charging ECU  207 , and determines whether or not the charging rate of the battery  11  becomes equal to or higher than a predetermined threshold value. When the charging rate of the battery  11  becomes equal to or higher than the predetermined threshold value, the CPU determines that the charging is complete. The CPU causes the process to wait at this step until the charging of the battery  11  is complete, and when the charging is complete, advances the process to Step S 115 . 
     In Step S 115 , the CPU transmits a signal instructing charging to be ended to the communication ECU  206 . When the communication ECU  206  receives the signal instructing charging to be ended from the vehicle control ECU  201 , the communication ECU  206  causes the in-vehicle communication device  223  to transmit the “signal instructing charging to be ended” to the equipment communication device  91  by wireless communication. As a result, power transmission by the wireless power supply device  90  is stopped (ended). The wireless power supply device  90  may acquire information indicating the charging rate of the battery  11  of the vehicle  10  by wireless communication, and stop power transmission based on the acquired information indicating the charging rate. In this case, the processing steps of Step S 114  and Step S 115  are not required. 
     When wireless communication to and from the wireless power supply device  90  has failed to be established in Step S 104 , the CPU advances the process to Step S 116 . In this case, a power transmission unit  92  of the wireless power supply device  90  is not installed in the parking space PS. Then, the processing step of each of Step S 116 , Step S 117 , Step S 118 , Step S 119 , Step S 120 , and Step S 121  is executed. The processing contents of those steps are the same as the processing contents of the steps of Step S 107 , Step S 108 , Step S 109 , Step S 110 , Step S 111 , and Step S 112 , respectively, and hence description thereof is omitted here. However, the position and orientation of the target parking area image on the plan view image included in the set image in Step S 116  are a position (for example, the center position of the parking space PS) and an orientation (for example, an orientation having a higher priority) determined in advance. 
     With the parking assist routine described above, power transmission units  92  having different external appearances can be detected by using the external appearance information corresponding to the identification information acquired from the wireless power supply device  90 . Therefore, regardless of the external appearance of the power transmission unit  92  installed in the parking space PS, the vehicle  10  can be automatically parked in the position suitable for charging and in the orientation which fits well in the parking space PS. 
     Description has been given of the at least one embodiment of the present invention, but the present invention is not limited to the at least one embodiment described above. The present invention may adopt various modification examples without departing from the spirit of the present invention. 
     For example, in the at least one embodiment described above, there has been described the configuration in which the power receiving unit  224  includes the power receiving coil  225  and can receive the transmission of power from the power transmission unit  92  of the wireless power supply device  90  in a non-contact manner. However, the power receiving unit  224  is not limited to such a configuration. Specifically, the power receiving unit  224  may have a configuration capable of receiving the transmission of power by contacting the power receiving unit  224  with a power transmission unit of a contact-type power supply device. For example, there has been known a contact-type power supply device including a power transmission unit configured to contact the power receiving unit  224  arranged in the vehicle  10  by ascending. The power receiving unit  224  of the parking assist apparatus  20  according to the at least one embodiment of the present invention may be configured to be able to receive the transmission of power by contacting the power transmission unit of such a contact-type power supply device. In order for the power transmission unit of a contact-type power supply device to contact the power receiving unit  224  installed in the vehicle  10  so as to be able to transmit power, the power receiving unit  224  installed in the vehicle  10  and the power transmission unit installed in the parking space PS are required to be aligned. According to the at least one embodiment of the present invention, various types of power transmission units having different external appearances can be detected, and hence the target parking area TA can be set in a position suitable for charging regardless of the external appearance of the power transmission unit installed in the parking space PS. 
     Further, in the at least one embodiment described above, as the parking assist control, control of parking the vehicle  10  in the target parking area TA without requiring the driver to operate the accelerator pedal, the brake pedal, or the steering wheel has been described. However, the parking assist control is not limited to such control. For example, the parking assist control may be control performed by controlling the steering angle of the steered wheels of the vehicle  10  so that the vehicle  10  travels along the target travel route TR and causing the vehicle  10  to travel in accordance with the operation of the accelerator pedal and the shift operation by the user. In short, the parking assist control may be any control of assisting the parking of the vehicle  10  in the target parking area TA. 
     Further, in the at least one embodiment described above, there has been described the configuration in which the in-vehicle communication device  223  and the equipment communication device  91  can wirelessly communicate to and from each other based on the first communication method and the second communication method which are different from each other, and the in-vehicle communication device  223  acquires identification information from the wireless power supply device  90  by wireless communication based on the first communication method and transmits a signal instructing charging to be started or charging to be ended to the wireless power supply device  90  by wireless communication based on the second communication method. However, the present invention is not limited to such a configuration. For example, the communication method for wireless communication to be used when the in-vehicle communication device  223  acquires the identification information from the equipment communication device  91  may be the same communication method as the communication method for wireless communication to be used when the in-vehicle communication device  223  transmits a signal instructing charging to be started or charging to be ended to the equipment communication device  91 . The specific methods of the first communication method and the second communication method are not particularly limited, and related-art publicly known communication methods (communication standards) can be applied. 
     Further, the “information relating to the features of the external appearance” is not limited to feature point information. For example, the “information relating to the features of the external appearance” may be an image (image data) of the power transmission unit  92 . In this case, the image of the power transmission unit  92  included in the plan view image can be detected by using the image data as the template image and the plan view image as the search image. 
     Moreover, related-art publicly known methods and processing can be applied to the method of setting the target travel route TR and the parking travel processing. Similarly, a related-art publicly known method can be applied to the method of identifying the position in the real coordinate system from the position of the image of the power transmission unit  92  included in the image data acquired from each of the cameras  210 ,  211 ,  212 , and  213  (in other words, the coordinate conversion method).