Parking assistance method and parking assistance device

Abstract

To improve safety in a case where attention of a user deviates from a vehicle, in performing parking control by which the vehicle is moved to a target stop position on the basis of an instruction from the user who is outside the vehicle.SOLUTION: In a parking support method, a controller 16 is made to execute processing (S5) for determining whether a predetermined end part 2a of a portable terminal 2 is pointed to a vehicle 1 or not and processing (S9) for making a vehicle speed at which the vehicle 1 is allowed to automatically travel to a target parking position at the time when the predetermined end part 2a is not pointed to the vehicle 1 lower than the vehicle speed at the time when the end part is pointed to the vehicle 1.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a parking assistance method and a parking assistance device. [Background technology]

[0002] Patent Document 1 proposes a parking control method for controlling an operation of parking a vehicle in a parking space by operating a terminal device outside the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2018 / 066069 Summary of the Invention [Problem to be solved by the invention]

[0004] When performing parking control to move a vehicle to a target stopping position based on an instruction from a user outside the vehicle, it is preferable from the viewpoint of safety that the user pay attention to the moving vehicle. However, the user does not necessarily keep paying attention to the vehicle during parking control. The present invention aims to improve safety when performing parking control to move a vehicle to a target stopping position based on instructions from a user outside the vehicle, in the event that the user's attention is diverted from the vehicle. [Means for solving the problem]

[0005] In one aspect of the parking assistance method of the present invention, the vehicle is driven to a target parking position in response to a signal from a mobile terminal outside the vehicle, and a controller is caused to execute a process of determining whether a predetermined end of the mobile terminal is directed to the vehicle, and a process of lowering a vehicle speed at which the vehicle is automatically driven to the target parking position when the predetermined end is not directed to the vehicle, compared to a case where the predetermined end is directed to the vehicle. Effect of the Invention

[0006] According to the present invention, when parking control is performed to move a vehicle to a target parking position based on instructions from a user outside the vehicle, safety can be improved in the event that the user's attention is diverted from the vehicle. [Brief description of the drawings]

[0007] [Figure 1] 1 is a diagram illustrating an example of a schematic configuration of a parking assistance system according to an embodiment. [Diagram 2] 1 is an explanatory diagram of an example of a method for measuring the distance between a vehicle and a ranging antenna of a mobile terminal; [Diagram 3] FIG. 1 is an explanatory diagram of the orientation of a mobile terminal. [Figure 4] FIG. 1 is an explanatory diagram of the orientation of a mobile terminal. [Diagram 5] 10 is an explanatory diagram of the angle between the direction from the mobile terminal to the vehicle and the orientation of the mobile terminal. FIG. [Figure 6] 4 is a flowchart of an example of a parking assistance method according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] (composition) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the description of the drawings, the same or similar parts are given the same or similar reference numerals, and duplicated explanations are omitted. Each drawing is schematic and may differ from the actual one. The embodiments shown below are examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention is not limited to the devices and methods exemplified in the following embodiments. The technical idea of ​​the present invention can be modified in various ways within the technical scope described in the claims.

[0009] 1 is a diagram showing an example of a schematic configuration of a parking assistance system 100 according to an embodiment. The parking assistance system 100 includes a positioning device 11, an external sensor 12, a vehicle sensor 13, a distance measurement antenna 14, a data communication antenna 15, a controller 16, and an actuator 17, all of which are mounted on a vehicle 1. In the attached drawings, the antenna is referred to as "ANT." The parking assistance system 100 also includes a portable terminal 2 used by a user of the parking assistance system 100. The identifier (ID) of the portable terminal 2 is registered in advance in the controller 16 of the vehicle 1 that is the target of parking assistance control.

[0010] The mobile terminal 2 may be, for example, a remote control terminal (such as a KEYFOB) that locks and unlocks the vehicle 1 and starts and stops automatic parking. The mobile terminal 2 may also be a portable terminal device (such as a smartphone or a PDA (Personal Digital Assistant)) that can send and receive information to and from the controller 16 of the vehicle 1. The mobile terminal 2 includes distance measurement antennas 20a, 20b, and 20c, a data communication antenna 21, a gyro sensor 22, and a control unit 23. One antenna may be used as both the distance measurement antennas 20a to 20c and the data communication antenna 21.

[0011] The positioning device 11 measures the current position of the vehicle 1. The positioning device 11 may include, for example, a Global Navigation System (GNSS) receiver. The GNSS receiver is, for example, a Global Positioning System (GPS) receiver, and receives radio waves from multiple navigation satellites to measure the current position of the vehicle 1. The external sensor 12 detects objects within a predetermined distance range from the vehicle 1 (for example, a detection area of ​​the external sensor 12). The external sensor 12 detects the surrounding environment of the vehicle 1, such as the relative position between the vehicle 1 and objects present around the vehicle 1, the distance between the vehicle 1 and the objects, and the direction in which the objects exist. The external sensor 12 may include, for example, a camera that captures the surrounding environment of the vehicle 1. The external sensor 12 may include a distance measuring device such as a laser range finder (LRF), a radar, or a laser radar of a Light Detection and Ranging (LiDAR). The external sensor 12 may also include an obstacle sensor, such as a sonar, that detects obstacles around the vehicle 1.

[0012] The vehicle sensor 13 detects various information (vehicle information) obtained from the vehicle 1. The vehicle sensor 13 may include, for example, a vehicle speed sensor that detects the traveling speed (vehicle speed) of the vehicle 1, a wheel speed sensor that detects the rotational speed of each tire equipped on the vehicle 1, a three-axis acceleration sensor (G sensor) that detects the acceleration (including deceleration) in three axial directions of the vehicle 1, a steering angle sensor that detects the steering angle (including the turning angle), a gyro sensor that detects the angular velocity generated in the vehicle 1, and a yaw rate sensor that detects the yaw rate.

[0013] The distance measurement antenna 14 is an antenna used for measuring the distance between the vehicle 1 and each of the distance measurement antennas 20a to 20c of the portable terminal 2. The measurement of the distance between the vehicle 1 and the distance measurement antennas 20a to 20c of the portable terminal 2 will be described later. The data communication antenna 15 is an antenna used for data communication between the control unit 23 of the mobile terminal 2 and the controller 16. Note that a single antenna may be used as both the distance measurement antenna 14 and the data communication antenna 15.

[0014] The controller 16 is an electronic control unit (ECU) that performs parking assistance control of the vehicle 1. The controller 16 includes a processor 18 and peripheral components such as a storage device 19. The processor 18 may be, for example, a central processing unit (CPU) or a micro-processing unit (MPU). The storage device 19 may include a semiconductor storage device, a magnetic storage device, an optical storage device, or the like. The functions of the controller 16 described below are realized, for example, by the processor 18 executing a computer program stored in the storage device 19. Note that the controller 16 may be formed of dedicated hardware for executing each of the information processes described below.

[0015] The actuator 17 generates vehicle behavior of the vehicle 1 by operating the steering device, the drive device, and the braking device of the vehicle 1 in response to a control signal from the controller 16. The actuator 17 includes a steering actuator, an accelerator opening actuator, and a brake control actuator. The steering actuator operates a steering device to control the steering direction and steering amount of the vehicle. The accelerator opening actuator operates a drive device such as an engine and a drive motor to control the acceleration of the vehicle 1. The brake control actuator operates a braking device to control the deceleration of the vehicle 1.

[0016] The following describes parking assistance control by the controller 16. The controller 16 executes parking assistance control to automatically park the vehicle 1 at a target parking position (parking space) based on an instruction from a user outside the vehicle 1. The user operates the mobile terminal 2 to instruct the controller 16 to move and stop the vehicle 1 at the target parking position. An operator (e.g., a parking assist button) for instructing parking assist control may be provided inside the vehicle 1. The user may instruct the controller 16 to move and stop the vehicle 1 to the target parking position by operating the operator inside the vehicle.

[0017] In the parking assistance control, the controller 16 detects the positions of targets around the vehicle 1 based on, for example, an image captured by the camera of the external sensor 12 or point cloud data output from a distance measuring device. The targets are features that serve as landmarks for identifying the current position of the vehicle 1, and may be obstacles such as road markings (road signs, dividing lines, and road markings) painted on the road surface, road boundaries, curbs, guardrails, and utility poles. The controller 16 detects the current position of the vehicle 1 by comparing position information of known targets stored in a specified storage medium (e.g., a storage device 19) with position information of targets around the vehicle 1 detected by the external sensor 12.

[0018] The controller 16 also sets a target parking position for parking the vehicle 1. For example, the target parking position closest to the current position of the vehicle 1 may be selected from among the target parking positions pre-stored in a predetermined storage medium. Alternatively, the target parking position may be set by capturing an image of the surroundings of the vehicle 1 with the camera of the external sensor 12, displaying the surrounding image on a display screen (not shown) of the mobile terminal 2 or a display screen (not shown) inside the vehicle cabin, and having the user specify the target parking position on the surrounding image.

[0019] The controller 16 generates a target driving trajectory for moving the vehicle 1 from the current position of the vehicle 1 to the target parking position, and a target vehicle speed profile which is a profile of the vehicle speed at which the vehicle 1 travels along the target driving trajectory. The controller 16 controls the actuator 17 so that the vehicle 1 travels along a target travel trajectory and in accordance with a target vehicle speed profile.

[0020] At this time, the controller 16 drives the vehicle 1 only while the user is continuously operating the mobile terminal 2 or an operating device inside the vehicle to instruct the vehicle 1 to move, and stops the vehicle 1 when the user stops operating it. For example, the vehicle 1 may be driven when a button or touch panel of the mobile terminal 2 or a parking support button in the vehicle is continuously pressed. Also, the vehicle 1 may be driven when a predetermined gesture (for example, drawing a circle or a figure eight) is continuously made on the touch panel of the mobile terminal 2. While the user is operating the portable terminal 2, the control unit 23 of the portable terminal 2 transmits a command signal to command the vehicle 1 to travel from the data communication antenna 21 to the vehicle 1. The controller 16 judges whether the user is operating the portable terminal 2 based on whether the command signal is received by the data communication antenna 15.

[0021] In this way, when performing parking assistance control to move vehicle 1 to a target stopping position based on instructions from a user outside the vehicle, it is preferable from a safety standpoint that the user pays attention to vehicle 1 while it is moving. However, the user does not necessarily keep his / her eyes on the vehicle 1 during parking assistance control, and may operate the mobile terminal 2 while taking his / her eyes off the vehicle 1.

[0022] Therefore, the controller 16 determines whether or not a predetermined end 2a of the mobile terminal 2 is pointed toward the vehicle 1, and when the end 2a is not pointed toward the vehicle 1, the controller 16 lowers the vehicle speed at which the vehicle 1 automatically travels to the target parking position compared to when the end 2a is pointed toward the vehicle 1. For example, when the end 2a is not pointed toward the vehicle 1, the controller 16 lowers the maximum speed of the target vehicle speed profile compared to when the end 2a is pointed toward the vehicle 1. This makes it possible to determine that the user's attention is diverted from the vehicle 1 when the user is not pointing the end 2a of the mobile terminal 2 at the vehicle 1, and by reducing the speed of the vehicle 1, it is possible to improve safety when the user's attention is diverted from the vehicle. Note that "reducing the vehicle speed" also includes stopping the vehicle 1 (i.e., setting the vehicle speed to 0 km / h).

[0023] At least one of the ends of the mobile terminal 2 in three orthogonal axial directions (e.g., the front end, rear end, left end, right end, top end and bottom end) is specified in advance as the end 2a to be directed toward the vehicle 1 during parking assistance control. For example, in a normal usage state in which a user holds and operates the mobile terminal 2, the end opposite the end 2b facing the user may be designated in advance as the end 2a to be directed toward the vehicle 1 during parking assistance control.

[0024] The controller 16 can determine whether the end portion 2a is directed toward the vehicle 1 in various ways. For example, the controller 16 may determine whether the end portion 2a is directed toward the vehicle 1 based on the distances between the vehicle 1 and three or more different positions of the mobile terminal 2. For this purpose, the control unit 23 of the portable terminal 2 measures the distance between the vehicle 1 and the distance measurement antennas 20a to 20c arranged at different positions of the portable terminal 2. The number of distance measurement antennas provided on the portable terminal 2 is not limited to three, and may be four or more.

[0025] For example, the control unit 23 may measure each of the distances between the ranging antennas 20a-20c and the ranging antenna 14 (i.e., each of the distances between the ranging antennas 20a-20c and the vehicle 1) based on the arrival time of radio waves between the ranging antennas 20a-20c of the portable terminal 2 and the ranging antenna 14 of the vehicle 1. The control unit 23 may measure each of the distances between the ranging antennas 20a-20c and the ranging antenna 14 based on a known distance measurement technique, for example, a Time of Flight (TOF) technique.

[0026] 2 is a diagram illustrating an example of a method for measuring the distance between the ranging antenna 20a and the ranging antenna 14. The controller 16 of the vehicle 1 transmits a tag signal from the ranging antenna 14 and stores a time stamp Tsp at that time. The control unit 23 of the portable terminal 2 stores a time stamp Trp when the tag signal is received by the ranging antenna 20a, and also transmits an anchor signal from the ranging antenna 20a in response to the tag signal, and stores a time stamp Tsr at that time.

[0027] The controller 16 stores a timestamp Trr when the anchor signal is received by the ranging antenna 14, and transmits a timestamp signal from the ranging antenna 14. The timestamp signal includes a timestamp Tsf when the timestamp signal is transmitted, and the stored timestamps Tsp and Trr. The control unit 23 acquires a timestamp Trf when the timestamp signal is received by the ranging antenna 20a. The control unit 23 calculates the time of flight TOF based on the following formula: TOF={(Trr-Tsp)-(Tsr-Trp)+(Trf-Tsr)-(Tsf-Trr)} / 4

[0028] The control unit 23 measures the distance Da between the ranging antenna 20a and the ranging antenna 14 based on the time of flight TOF. The distance Db between the ranging antenna 20b and the ranging antenna 14, and the distance Dc between the ranging antenna 20c and the ranging antenna 14 are also measured in the same manner. Note that the tag signal and the time stamp signal may be transmitted from the portable terminal 2 to the vehicle 1, and an anchor signal may be transmitted from the vehicle 1 to the portable terminal 2, so that the controller 16 of the vehicle 1 measures the distances Da to Dc.

[0029] 1, the control unit 23 of the mobile terminal 2 transmits, from the data communication antenna 21, distance information on the distances Da to Dc between the distance measurement antennas 20a to 20c and the distance measurement antenna 14, respectively. The controller 16 of the vehicle 1 receives the distance information of the distances Da to Dc transmitted from the portable terminal 2 via the data communication antenna 15. The controller 16 determines whether or not the end 2a is directed toward the vehicle 1 based on the distances Da to Dc.

[0030] Please refer to Fig. 3. Now, an axis connecting end 2a of mobile terminal 2 and end 2b opposite end 2a is defined as axis ax1, and an axis perpendicular to axis ax1 is defined as axis ax2. For example, the ranging antennas 20b and 20c are disposed on the axis ax2, and the ranging antenna 20a is disposed at a position deviated from the axis ax2. For example, as shown in Fig. 3, the ranging antenna 20a is disposed at a position closer to the end 2a than the ranging antennas 20b and 20c. Then, when the portable terminal 2 is in the position shown by the arrows 30 and 31, the distances Da to Dc between the distance measurement antennas 20a to 20c and the distance measurement antenna 14 are different from each other, and it can be determined that the end 2a is not pointed toward the vehicle 1.

[0031] Furthermore, when the portable terminal 2 is in the position shown by the arrow 32, the distances Db, Dc of the ranging antennas 20b, 20c are equal to each other, and the distance Da of the ranging antenna 20a is shorter than the distances Db, Dc, so it can be determined that the end 2a is directed toward the vehicle 1. In addition, when the distances Db and Dc are equal to each other and the distance Da is longer than the distances Db and Dc, the end 2a is facing away from the vehicle 1, and the controller 16 can determine that the end 2a is not facing the vehicle 1. In addition, the distance measurement antenna 20a may be disposed at a position farther from the end 2a than the distance measurement antennas 20b and 20c. In this case, the controller 16 determines that the end 2a is directed toward the vehicle 1 when the distances Db and Dc are equal to each other and the distance Da of the distance measurement antenna 20a is longer than the distances Db and Dc.

[0032] The above-mentioned determination method using the distance measurement antennas 14, 20a to 20c is just one example, and the controller 16 may use various other methods to determine whether or not the end portion 2a is directed toward the vehicle 1. For example, a positioning device and a magnetic sensor may be provided in the portable terminal 2 to detect the current position and attitude, and whether or not the end portion 2a is directed toward the vehicle 1 may be determined based on the current position of the vehicle 1 measured by the positioning device 11 and the current position and attitude of the portable terminal 2.

[0033] Please refer to Fig. 4. Reference numeral 24 denotes an operation surface of the mobile terminal 2 provided with a user interface that accepts operations by the user to instruct the vehicle 1 to travel during parking assistance. The operation surface 24 may be provided with a user interface such as a touch panel or buttons. 4, the end 2a is directed toward the vehicle 1, and the operation surface 24 of the mobile terminal 2 faces upward. When a user is using the mobile terminal 2, it is considered that the operation surface 24 faces upward as shown in FIG. Conversely, when the operation surface 24 is not facing upward, even if something is touching the operation surface 24 and it appears as if the mobile terminal 2 is being operated, in reality, the mobile terminal 2 is inside the user's clothing or bag, and the user is not operating the mobile terminal 2.

[0034] Therefore, the gyro sensor 22 detects the attitude of the portable terminal 2. The control unit 23 transmits attitude information indicating the attitude of the portable terminal 2 from the data communication antenna 21. The controller 16 of the vehicle 1 receives the attitude information transmitted from the portable terminal 2 via the data communication antenna 15 . The controller 16 determines whether the operation surface 24 faces upward based on the attitude information. When the end 2a is not facing the vehicle 1 or the operation surface 24 is not facing upward, the controller 16 slows the vehicle speed compared to when the end 2a is facing the vehicle 1 and the operation surface 24 faces upward.

[0035] See Figure 5. The controller 16 may calculate the angle θ between the direction d1 in which the end 2a is facing and the direction d2 from the end 2a towards the vehicle 1. For example, the controller 16 may calculate the position P of the vehicle 1 on a coordinate system based on the position Pr of the portable terminal 2 based on the distances Da to Dc between the ranging antennas 20a to 20c and the ranging antenna 14, and the known positions at which the ranging antennas 20a to 20c are placed on the portable terminal 2. The controller 16 may calculate the direction d2 from the end 2a toward the vehicle 1 from the position of the end 2a and the position P of the vehicle 1, and calculate the angle θ between the direction d1 in which the end 2a is facing and the direction d2.

[0036] When the angle θ is equal to or greater than a predetermined threshold value Ta, the controller 16 may stop the vehicle 1. In other words, the parking control for automatically driving the vehicle 1 to the target parking position may be stopped. On the other hand, when the angle θ is less than the predetermined threshold value Ta, the controller 16 may set the vehicle speed of the vehicle 1 during parking assistance control according to the angle θ. For example, when the angle θ is large, the vehicle speed may be set lower than when the angle θ is small. For example, the vehicle speed may be set lower as the angle θ increases. For example, the maximum speed of the target vehicle speed profile may be set lower as the angle θ increases.

[0037] Furthermore, even if the end 2a is operated with the end 2a pointed toward the vehicle 1, if there is a risk of obstacles around the vehicle, it is preferable to limit the vehicle speed of the vehicle 1 during parking assistance control. For this reason, the controller 16 calculates a risk R for an obstacle around the vehicle 1 detected by the external sensor 12. For example, the controller 16 may calculate, as the risk R, the reciprocal of the distance from the vehicle 1 to the obstacle or the reciprocal of the time to collision TTC.

[0038] The controller 16 may set the vehicle speed of the vehicle 1 during parking assist control according to the risk R. For example, when the risk R is high, the vehicle speed may be set lower than when the risk R is low. For example, the higher the risk R, the lower the vehicle speed may be set. For example, the higher the risk R, the lower the maximum speed of the target vehicle speed profile may be set. Also, for example, the controller 16 may determine whether the risk R is equal to or greater than a predetermined threshold value Tr. When the risk R is equal to or greater than the predetermined threshold value Tr, the controller 16 may set the vehicle speed in accordance with the risk R, regardless of the magnitude of the angle θ between the direction d1 in which the end portion 2a is facing and the direction d2 from the end portion 2a toward the vehicle 1. When the risk R is less than the predetermined threshold value Tr, the controller 16 may set the vehicle speed in accordance with the angle θ.

[0039] (operation) FIG. 6 is a flowchart of an example of a parking assistance method according to the embodiment. In step S1, the controller 16 detects the current position of the vehicle 1. In step S2, the controller 16 sets a target parking position where the vehicle 1 is to be parked. In step S3, the controller 16 generates a target driving trajectory for moving the vehicle 1 from the current position of the vehicle 1 to the target parking position.

[0040] Thereafter, the user operates the mobile terminal 2 to instruct the vehicle 1 to move, and the controller 16 causes the vehicle 1 to travel along the target travel path and park it at the target parking position. In step S4, the controller 16 determines whether or not the user is operating the mobile terminal 2. If the mobile terminal 2 is being operated (S4: Y), the process proceeds to step S5. If the mobile terminal 2 is not being operated (S4: N), the process proceeds to step S6.

[0041] In step S5, the controller 16 determines whether the angle θ between the direction d1 in which the end 2a is facing and the direction d2 from the end 2a toward the vehicle 1 is equal to or greater than a predetermined threshold value Ta. If the angle θ is equal to or greater than the predetermined threshold value Ta (S5: Y), the process proceeds to step S6. If the angle θ is not equal to or greater than the threshold value Ta (S5: N), the process proceeds to step S7. In step S6, the controller 16 stops the vehicle 1. After that, the process proceeds to step S10.

[0042] In step S7, the controller 16 determines whether or not the risk R to an obstacle around the vehicle is equal to or greater than a predetermined threshold Tr. If the risk R is equal to or greater than the predetermined threshold Tr (S7: Y), the process proceeds to step S8. If the risk R is not equal to or greater than the predetermined threshold Tr (S7: N), the process proceeds to step S9. In step S8, the controller 16 controls the speed at which the vehicle 1 travels along the target travel path in accordance with a target vehicle speed profile according to the risk R. For example, the vehicle speed may be set lower as the risk R increases. After that, the process proceeds to step S10.

[0043] In step S9, the controller 16 controls the speed at which the vehicle 1 travels along the target travel path according to a target vehicle speed profile according to the angle θ between the direction d1 in which the end 2a is facing and the direction d2 from the end 2a toward the vehicle 1. For example, the vehicle speed may be set lower as the angle θ increases. The process then proceeds to step S10. In step S10, the controller 16 determines whether the vehicle 1 has reached the target parking position. If the vehicle 1 has not reached the target parking position (S10: N), the process returns to step S4. If the vehicle 1 has reached the target parking position (S10: Y), the process ends.

[0044] (Effects of the embodiment) (1) The controller 16 determines whether or not a specific end 2a of the mobile terminal 2 is pointed toward the vehicle 1, and when the specific end 2a is not pointed toward the vehicle 1, the controller 16 reduces the vehicle speed at which the vehicle 1 automatically travels to the target parking position compared to when the specific end 2a is pointed toward the vehicle 1. When performing parking control to move the vehicle to a target stopping position based on an instruction from a user outside the vehicle, the vehicle speed can be restricted if the user's attention is shifted away from the vehicle, thereby improving safety.

[0045] (2) The controller 16 may stop the parking control that automatically drives the vehicle 1 to the target parking position when the angle between the direction in which the predetermined end 2a is facing and the direction from the end 2a toward the vehicle 1 is equal to or greater than a predetermined angle. This can improve safety by stopping the vehicle 1 when there is a high possibility that the user's attention has shifted from the vehicle. (3) When the angle between the direction in which the specified end 2a is facing and the direction from the end 2a toward the vehicle 1 is large, the controller 16 may slow down the vehicle speed compared to when this angle is small. For example, the vehicle speed may be slower as this angle increases. This allows the vehicle speed to be limited depending on the degree to which the user's attention is diverted from the vehicle, thereby improving safety.

[0046] (4) Based on the arrival time of radio waves between three or more antennas 20a to 20c arranged at different positions on the mobile terminal 2 and an antenna 14 provided on the vehicle 1, the distances Da to Dc between the vehicle 1 and the three or more antennas 20a to 20c may be measured, and the direction in which a specific end 2a is pointed may be detected according to the distances Da to Dc between the vehicle 1 and the three or more antennas 20a to 20c, respectively. This makes it possible to determine whether or not the predetermined end 2a of the portable terminal 2 is facing the vehicle 1. Also, it is possible to detect the direction in which the predetermined end 2a is facing.

[0047] (5) The risk of an obstacle around the vehicle 1 is detected by a sensor, and the controller 16 may set the vehicle speed lower when the risk is high than when the risk is low. For example, the higher the risk, the lower the vehicle speed may be. This allows the vehicle speed to be limited when there is a high risk of obstacles around the vehicle 1, thereby improving safety. (6) The controller 16 determines whether the risk is greater than or equal to a predetermined value, and if the risk is greater than or equal to the predetermined value, may set the vehicle speed based on the risk, regardless of the magnitude of the angle between the direction in which the predetermined end 2a is facing and the direction from the end 2a toward the vehicle 1. As a result, even if the predetermined end 2a is directed toward the vehicle 1, the vehicle speed can be limited according to the risk of obstacles around the vehicle 1, thereby improving safety.

[0048] (7) The controller 16 determines whether the operation surface 24 of the portable terminal 2 is facing upward, and if the specified end 2a is not facing toward the vehicle 1 or the operation surface 24 is not facing upward, the controller 16 may slow down the vehicle speed compared to when the specified end 2a is facing toward the vehicle 1 and the operation surface 24 is facing upward. This makes it possible to prevent erroneous detection of an operation on the operation surface 24 when the user is not operating the operation surface 24 of the mobile terminal 2. [Explanation of symbols]

[0049] 100... parking assistance system, 1... vehicle, 2... mobile terminal, 2a, 2b... end portion, 11... positioning device, 12... external sensor, 13... vehicle sensor, 14, 20a, 20a, 20b... ranging antenna, 15, 21... data communication antenna, 16... controller, 17... actuator, 18... processor, 19... storage device, 22... gyro sensor, 23... control unit, 24... operation surface

Claims

1. A parking assistance method for parking a vehicle to a target parking position in response to a signal from a mobile terminal outside the vehicle, comprising: determining whether a predetermined end of the mobile terminal is pointed toward the vehicle; When the predetermined end is not directed toward the vehicle, a process of lowering a vehicle speed at which the vehicle automatically travels to the target parking position compared to a case in which the predetermined end is directed toward the vehicle; A parking assistance method comprising: causing a controller to execute the above steps.

2. 2. The parking assistance method according to claim 1, wherein the controller stops parking control for automatically driving the vehicle to the target parking position when an angle between a direction in which the specified end is facing and a direction from the end toward the vehicle is equal to or greater than a specified angle.

3. 3. The parking assistance method according to claim 1, wherein the controller reduces the vehicle speed when an angle between a direction in which the predetermined end is facing and a direction from the end toward the vehicle is large, compared to when the angle is small.

4. The parking assistance method according to any one of claims 1 to 3, characterized in that the controller reduces the vehicle speed as the angle between the direction in which the predetermined end is pointed and the direction from the end to the vehicle becomes larger.

5. measuring distances between the vehicle and each of the three or more antennas based on a time taken for radio waves to travel between the three or more antennas arranged at different positions on the mobile terminal and an antenna provided on the vehicle; detecting a direction in which the predetermined end is facing according to a distance between the vehicle and each of the three or more antennas; 5. The parking assistance method according to claim 1, wherein the vehicle is driven in a direction parallel to the vehicle axis.

6. Detecting risks associated with obstacles around the vehicle using a sensor provided on the vehicle; 6. The parking assistance method according to claim 1, wherein the controller reduces the vehicle speed when the risk is high compared to when the risk is low.

7. Detecting risks associated with obstacles around the vehicle using a sensor provided on the vehicle; 6. The parking assistance method according to claim 1, wherein the controller reduces the vehicle speed as the risk increases.

8. The parking assistance method according to claim 6 or 7, characterized in that the controller determines whether the risk is equal to or greater than a predetermined value, and if the risk is equal to or greater than the predetermined value, sets the vehicle speed based on the risk, regardless of the magnitude of the angle between the direction in which the predetermined end is facing and the direction from the end to the vehicle.

9. The parking assistance method according to any one of claims 1 to 8, characterized in that the controller determines whether an operation surface of the mobile terminal is facing upward, and when the specified end is not facing the vehicle or the operation surface is not facing upward, the controller makes the vehicle speed slower than when the specified end is facing the vehicle and the operation surface is facing upward.

10. A parking assistance device that drives a vehicle to a target parking position in response to a signal from a mobile terminal outside the vehicle, determining whether a predetermined end of the mobile terminal is pointed toward the vehicle; When the predetermined end is not directed toward the vehicle, a process of lowering a vehicle speed at which the vehicle automatically travels to the target parking position compared to a case in which the predetermined end is directed toward the vehicle; A parking assistance device comprising: a controller that executes the above-mentioned steps.

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