Parking assistance method and parking assistance device

Abstract

With this parking assistance method of assisting parking of a vehicle in a target parking position, a case is assumed in which a target position candidate, which is a candidate of a target parking position present around the vehicle, cannot be detected (S1: N), and in this case: if the factor of undetectability of the parking position candidate is an environmental factor depending on an environment of the vehicle, the environmental factor is displayed on a display device (S5); whereas if the factor of undetectability of the parking position candidate is a user factor depending on a user, the user factor is displayed on the display device (S4).

Description

Technical Field

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

Background Art

[0002] The following Patent Document 1 describes that an alarm is output when it is determined that the vehicle is in a state where the parking operation should be prohibited during automatic parking by a parking assistance system.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the case of the parking assistance system of the above Patent Document 1, when the target parking position for parking the host vehicle cannot be detected, the user does not know the factor that the target parking position cannot be detected, and there is a risk that the user cannot cope with the situation where the target parking position cannot be detected. An object of the present invention is to facilitate a user's response to a situation where a target parking position cannot be detected in parking assistance for assisting parking of the host vehicle to the target parking position.

Means for Solving the Problems

[0005] According to one aspect of the present invention, a parking assistance method for assisting parking of the host vehicle to a target parking position is provided. In the parking assistance method, when a parking position candidate that is a candidate for the target parking position existing around the host vehicle cannot be detected, if the factor that the parking position candidate cannot be detected is an environmental factor that depends on the environment of the host vehicle, the environmental factor is displayed on a display device, and if the factor that the parking position candidate cannot be detected is a user factor that depends on the user, the user factor is displayed on the display device.

Effects of the Invention

[0006] According to the present invention, in parking assistance that assists in parking the vehicle at a target parking position, it becomes easier for the user to deal with situations where the target parking position cannot be detected. [Brief explanation of the drawing]

[0007] [Figure 1] This figure shows a schematic configuration example of a parking assistance device according to an embodiment. [Figure 2] (a) and (b) are schematic diagrams illustrating the parking assist control in the first assist mode. [Figure 3] This is a schematic diagram illustrating the parking assist control in the second assistance mode. [Figure 4] This is a schematic diagram of an example of a successful detection screen. [Figure 5] This is a schematic diagram of an example of the first help screen. [Figure 6] This is a schematic diagram of an example of the second help screen. [Figure 7] This is a flowchart of the driving assistance method according to the first embodiment. [Figure 8] Figure 1 is a block diagram showing an example of the controller's functional configuration. [Figure 9] This is a schematic diagram of an example of a search screen. [Figure 10] This is a schematic diagram of an example of a detection failure screen. [Figure 11] (a) and (b) are explanatory diagrams illustrating an example of user factors in the first support mode. [Figure 12] This is a flowchart of the driving assistance method according to the second embodiment. [Modes for carrying out the invention]

[0008] (First Embodiment) (composition) Figure 1 is a diagram showing a schematic configuration example of a parking assistance device according to an embodiment. The vehicle 1 is equipped with a parking assistance device 10 that assists in parking the vehicle 1 at a target parking position. The parking assistance device 10 assists in driving along a target parking path from the vehicle 1's current position to the target parking position. For example, automatic driving may be performed to control the vehicle 1 so that it drives along its target parking path to the target parking position. Automatic driving that controls the vehicle 1 to drive along its target parking path to the target parking position means controlling all or part of the steering angle, driving force, and braking force of the vehicle 1 to automatically perform all or part of driving along the target parking path. In addition, parking of the vehicle 1 may be assisted by displaying the target parking path and the vehicle 1's current position on a display device that can be seen by the user (e.g., the driver or other occupant) in the vehicle 1.

[0009] The positioning device 11 measures the current position of the vehicle 1. The positioning device 11 includes, for example, a Global Navigation Satellite System (GNSS) receiver. Map data is stored in the map database (map DB) 12. The map data stored in the map database 12 may be, for example, high-precision map data suitable for navigation or autonomous driving. The Human-Machine Interface (HMI) 13 is an interface device that exchanges information between the parking assist device 10 and the user. For example, the HMI 13 may be equipped with a display device that is visible to the user as an interface for presenting visual information to the user. The HMI 13 may also be equipped with a speaker or buzzer as an interface for presenting auditory information to the user. Furthermore, the HMI 13 may be equipped with an interface (touch panel, buttons, switches, levers, dials, keyboard, etc.) for receiving operational input from the user.

[0010] The shift switch (shift SW) 14 is a switch used by the driver or the parking assist device 10 to switch the shift position of the vehicle 1. The external sensor 15 detects objects within a predetermined distance range from the vehicle 1. The external sensor 15 detects the surrounding environment of the vehicle 1, such as the relative position of objects around the vehicle 1 and the vehicle 1, the distance between the vehicle 1 and the objects, and the direction in which the objects are located. The external sensor 15 may include, for example, a camera that photographs the surrounding environment of the vehicle 1. The external sensor 15 may also include distance measuring devices such as a laser rangefinder, radar, LiDAR (Light Detection and Ranging), or sonar. The vehicle sensor 16 detects various information (vehicle information) of the vehicle 1. For example, the vehicle sensor 16 may include a vehicle speed sensor that detects the driving speed of the vehicle 1, a three-axis acceleration sensor that detects the acceleration (including deceleration) of the vehicle 1 in three axes, and sensors that detect the steering angle of the steering wheel and the steering angle of the steering wheels. The parking switch (parking SW) 17 is a switch for activating the parking assistance control provided by the parking assistance device 10. The mode selector switch (mode selector SW) 18 is a switch for switching the control mode of the parking assist control provided by the parking assist device 10.

[0011] The controller 19 is an electronic control unit that performs parking assistance control of the vehicle 1. The controller 19 includes a processor 19a and peripheral components such as a storage device 19b. The processor 19a may be, for example, a CPU or an MPU. The storage device 19b may include a semiconductor storage device, a magnetic storage device, an optical storage device, etc. The functions of the controller 19 described below are realized, for example, by the processor 19a executing a computer program stored in the storage device 19b. The parking brake 20 generates frictional braking force on the wheels of the vehicle 1 according to user operation or control signals from the controller 19. The steering actuator 21a controls the steering direction and amount of the steering mechanism of the vehicle 1 in accordance with the control signal from the controller 19. The accelerator actuator 21b controls the accelerator opening of the drive unit, such as the engine or drive motor, in accordance with the control signal from the controller 19. The brake actuator 21c activates the braking unit in accordance with the control signal from the controller 19.

[0012] Next, the parking support control by the controller 19 will be described. The controller 19 may detect parking position candidates existing around the host vehicle 1, set the detected parking position candidates as target parking positions, and execute parking support control to support parking. For example, the controller 19 may detect parking position candidates existing around the host vehicle 1 from the target parking positions registered in advance in the storage device 19b. In the following description, the control mode of the parking support control for detecting parking position candidates from the target parking positions registered in advance and supporting parking may be referred to as the "first support mode". Also, for example, the controller 19 may detect an empty space such as a parking frame where parking is possible around the host vehicle 1 as a parking position candidate without using the target parking positions registered in advance. In the following description, the control mode of the parking support control for detecting an empty space around the host vehicle 1 as a parking position candidate without using the target parking positions registered in advance and supporting parking may be referred to as the "second support mode".

[0013] FIGS. 2(a) and 2(b) are schematic diagrams for explaining the parking support control in the first support mode. When using the parking support control in the first support mode, the target parking position 31 where the host vehicle 1 is to be parked is registered in the parking support device 10 in advance. Specifically, targets existing around the target parking position 31 are extracted and stored (registered) in the storage device 19b in advance. In the following description, the targets around the target parking position 31 stored in the storage device 19b are referred to as "learned targets". The round plots in FIG. 2(a) schematically represent the learned targets. When registering the target parking position 31 in the parking support device 10, for example, the user performs an operation (hereinafter sometimes referred to as a "registration operation") for instructing the registration of the target parking position 31.

[0014] For example, when the vehicle 1 is located near the target parking position 31 (for example, when the user manually drives the vehicle 1 to the target parking position 31), the controller 19 detects objects around the vehicle 1 with the external sensor 15 and stores them as learned objects. For example, objects may be detected from an ambient image obtained by taking a picture of the area around the vehicle 1 with a camera. For example, on the image captured by the camera, objects such as road markings, road boundaries, and obstacles may be detected as objects, such as edge points or corners of adjacent pixels where the brightness of adjacent pixels changes by a predetermined amount or points with distinctive shapes (feature points). The controller 19 stores learned target data relating to learned targets in the storage device 19b. For example, the learned target data may include data representing the features of the learned targets (hereinafter referred to as "feature data") and data on the relative positional relationship between the target parking position 31 and the learned targets (hereinafter referred to as "relative position data"). As relative position data, for example, the relative position of a learned object relative to the target parking position 31 may be stored. For example, the controller 19 can acquire the position of a learned object detected when its own vehicle 1 parks at the target parking position 31 as the relative position of the learned object relative to the target parking position 31. The coordinates of the learned object and the target parking position 31 in a coordinate system with a fixed point as the reference point (hereinafter referred to as the "map coordinate system") may also be stored.

[0015] Figure 2(b) is an explanatory diagram of an example of the process when parking assistance is performed. The controller 19 starts parking assistance control of the vehicle 1 when a user operation (hereinafter sometimes referred to as "start operation") is performed to instruct the user to start the parking assistance control of the vehicle 1. For example, the start operation may be an operation of the parking switch 17 by the user. The controller 19 may also start parking assistance control automatically when the vehicle 1 approaches the registered target parking position 31. The parking assistance device 10 may be switchable between an automatic start mode, in which parking assistance control is automatically started when the vehicle 1 approaches the registered target parking position 31, and a manual start mode, in which parking assistance control is not automatically started even when the vehicle 1 approaches the registered target parking position 31.

[0016] When parking assistance control begins, the controller 19 uses the external sensor 15 to extract objects around the vehicle 1. In the following description, objects around the vehicle 1 extracted during parking assistance will be referred to as "surrounding objects." In Figure 2(b), the triangular plot represents surrounding objects. The controller 19 matches learned objects with surrounding objects and associates identical feature points to detect registered target parking positions 31 as parking position candidates. Based on the relative positional relationship between the surrounding objects detected during parking assistance and the vehicle 1, and the relative positional relationship between the learned objects associated with the surrounding objects and the target parking position 31, the controller 19 calculates the relative position of the vehicle 1 with respect to the target parking position 31.

[0017] For example, the controller 19 calculates the position of the target parking position 31 on a coordinate system (hereinafter referred to as the "vehicle coordinate system") that is based on the current position of the vehicle 1. If the coordinates of the learned targets and the target parking position 31 on the map coordinate system are stored in the storage device 19b, the coordinates of the target parking position 31 on the map coordinate system may be converted to coordinates on the vehicle coordinate system based on the positions of the surrounding targets detected during parking assistance and the positions of the learned targets on the map coordinate system. Alternatively, the self-position of the vehicle 1 on the map coordinate system may be determined based on the positions of the surrounding targets detected during parking assistance and the positions of the learned targets on the map coordinate system, and the relative position of the vehicle 1 with respect to the target parking position 31 may be calculated from the difference between the coordinates of the vehicle 1 on the map coordinate system and the coordinates of the target parking position 31.

[0018] Figure 3 is a schematic diagram illustrating the parking assistance control in the second assistance mode. When the user performs an activation operation to instruct the activation of the parking assistance control, the controller 19 starts assisting with parking the vehicle 1. When the parking assistance control in the second assistance mode is activated, the controller 19 detects available parking spaces 31a to 31d around the vehicle 1 as candidate parking positions based on the detection results of the external sensor 15, which has detected the white lines 35 around the vehicle 1 and objects around the vehicle 1, and sets one of them as the target parking position.

[0019] For example, the controller 19 may detect available parking spaces around its own vehicle 1 as candidate parking positions based on the detection result of parking space line 35 indicating a parking space. Alternatively, the controller 19 may detect parked vehicles as objects around its own vehicle 1 and detect the space between parked vehicles as candidate parking positions. Once a parking position candidate is detected as described above, the controller 19 displays a detection success screen on the HMI 13's display device to inform the user that a parking position candidate has been successfully detected. Figure 4 is a schematic diagram of an example of a detection success screen. For example, the detection success screen 40a includes an image 41 generated by imaging the area around the vehicle 1, an overhead image 42 generated by converting the image of the area around the vehicle 1, a message display area 43 where notifications such as visual messages are displayed, a parking start button 44, and an end button 45.

[0020] The message display area 43 of the detection success screen 40a displays a visual message or other notification to inform the user that a parking position candidate has been detected. When the user operates the parking start button 44 or the parking end button 45 displayed on the display device, the touch panel on the display device detects these operations. When the parking start button 44 is operated, the controller 19 sets the parking position candidate as the target parking position 31 and calculates the target parking path 34 from the vehicle's current position 33 to the target parking position 31. Based on the calculated target parking path 34, the controller 19 performs parking assistance control for the vehicle 1. When the exit button 45 is pressed, the controller 19 stops the parking assistance control. The same applies when the exit button 45 is pressed on the search screen 40d and the detection failure screen 40e, which are shown in Figures 9 and 10 and will be described later.

[0021] On the other hand, if it is not possible to detect a parking position candidate, the controller 19 determines whether the reason for not being able to detect a parking position candidate is a user factor, which depends on the user, or an environmental factor, which depends on the environment of the vehicle 1. If the reason why a parking position candidate cannot be detected is due to a user-related factor, the controller 19 displays a first help screen on the HMI 13's display device to inform the user of the user-related factor. Figure 5 is a schematic diagram of an example of the first help screen. For example, the first help screen 40b includes an overview image 42, a user factor display area 46 that displays user factors, and a back button 47. When the user operates the back button 47, the touch panel on the display device detects this operation, and the controller 19 stops displaying the first help screen 40b.

[0022] If the reason why a parking spot candidate cannot be detected is an environmental factor, the controller 19 displays a second help screen on the HMI 13's display device to inform the user of the environmental factor. Figure 6 is a schematic diagram of an example of a second help screen. For example, the second help screen 40c includes an overview image 42, an environmental factors display area 48 that displays environmental factors, and a back button 47. When the user presses the back button 47, the controller 19 stops displaying the second help screen 40c.

[0023] (operation) Figure 7 is a flowchart of the driving assistance method of the first embodiment. In step S1, the controller 19 determines whether or not it was able to detect a parking position candidate. If a parking position candidate was detected (step S1:Y), the process proceeds to step S2. If a parking position candidate cannot be detected (step S1:N), the process proceeds to step S3. In step S2, the controller 19 displays a detection success screen 40a on the display device. In step S3, the controller 19 determines whether or not the reason for not being able to detect a parking position candidate is a user factor. If the reason for not being able to detect a parking position candidate is a user factor (step S3:Y), the process proceeds to step S4. If the reason for not being able to detect a parking position candidate is an environmental factor (step S3:N), the process proceeds to step S5. In step S4, the controller 19 displays a first help screen 40b on the display device. In step S5, the controller 19 displays a second help screen 40c on the display device.

[0024] (Second Embodiment) Figure 8 is a block diagram of an example of the functional configuration of the controller 19. When the HMI control unit 50 detects a user registering a target parking position 31, it outputs a map generation command to the map generation unit 55 to store the learned target data in the storage device 19b. When the HMI control unit 50 detects a user activating parking assistance control, it outputs a control start command to the parking assistance control unit 51 to start parking assistance control to the target parking position. The image conversion unit 52 converts the image captured by the camera into an overhead view image from a virtual viewpoint directly above the vehicle 1. The image conversion unit 52 converts the captured image into an overhead view image at predetermined intervals and accumulates the converted overhead view images along the vehicle 1's travel path to generate an ambient image, which is an image of the area surrounding the vehicle 1.

[0025] The self-position calculation unit 53 calculates the current position of the vehicle 1 on the map coordinate system as its own position by performing odometry (e.g., dead reckoning) based on vehicle information output from the vehicle sensor 16. The target detection unit 54 detects targets from the surrounding image output from the image conversion unit 52. The target detection unit 54 may detect the position of the target's feature points and their image features. The target detection unit 54 outputs the detected feature point positions and image features as target data to the map generation unit 55 and the target parking position detection unit 57. In addition, the self-position obtained from the self-position calculation unit 53 is output to the map generation unit 55 and the target parking position detection unit 57 in synchronization with the target detection. When the map generation unit 55 receives a map generation command from the HMI control unit 50 (i.e., when the registration operation for the target parking position 31 is performed), it generates learned target data and stores it in the storage device 19b as map data 56. For example, the map generation unit 55 receives target data and the position of the vehicle 1 on the map coordinate system synchronized with the target data from the target detection unit 54. The map generation unit 55 acquires the position information of the target parking position 31 in the map coordinate system. For example, the position calculated by the self-position calculation unit 53 when the vehicle 1 is located at the target parking position 31 may be acquired as the position information of the target parking position 31. The map generation unit 55 generates relative position data based on the positions of feature points included in the target data, the position information of the vehicle 1 synchronized with these points, and the position information of the target parking position 31. The map generation unit 55 acquires feature data from the target data output from the target detection unit 54. The trained target data, including this relative position data and feature data, is stored in the storage device 19b as map data 56.

[0026] When the parking assist device 10 is set to automatic start mode, the parking assist control unit 51 determines whether the current position of the vehicle 1 is near the registered target parking position 31. If the current position of the vehicle 1 is near the registered target parking position 31, the parking assist control unit 51 starts parking assist control and operates the parking assist device 10 in first assist mode. On the other hand, when the parking assist device 10 is set to manual start mode, the parking assist control unit 51 receives a control start command from the HMI control unit 50 and determines whether the current position of the vehicle 1 is near the registered target parking position 31. If the current position of the vehicle 1 is near the registered target parking position 31, the parking assist control unit 51 operates the parking assist device 10 in first assist mode. If the current position of the vehicle 1 is not near the registered target parking position 31, the parking assist control unit 51 operates the parking assist device 10 in second assist mode.

[0027] When the parking assistance control unit 51 starts parking assistance control, it determines whether predetermined system conditions for executing parking assistance control are met. If the system conditions are met, it outputs a parking position calculation command to the target parking position detection unit 57. If the system conditions are not met, it does not output a parking position calculation command to the target parking position detection unit 57. Therefore, the target parking position detection unit 57 does not perform detection of parking position candidates. In other words, the target parking position detection unit 57 does not determine whether or not parking position candidates can be detected. The system conditions may be, for example, that the shift position is not in the parking range or that the user is wearing a seat belt.

[0028] Upon receiving a parking position calculation command, the target parking position detection unit 57, in the case of parking assistance control in the first assistance mode, receives the target data output from the target detection unit 54 as target data for surrounding targets, and simultaneously receives the self-position of the vehicle 1 in the map coordinate system. The target parking position detection unit 57 detects registered target parking positions 31 as parking position candidates by matching learned targets with surrounding targets and associating targets with the same feature points. In other words, it determines whether or not it can detect registered target parking positions 31 based on whether or not the matching between learned targets and surrounding targets is successful. If the matching is successful (i.e., target parking positions 31 are detected), the target parking position detection unit 57 calculates the relative position of the vehicle 1 with respect to the target parking positions 31 based on the relative positional relationship between the surrounding targets and the vehicle 1 and the relative positional relationship between the learned targets associated with the surrounding targets and the target parking positions 31.

[0029] In the second support mode of parking assistance control, the target parking position detection unit 57 determines whether there is a parking space around the vehicle 1 (i.e., whether the target parking position 31 can be detected) based on the detection results of the external sensor 15, which detects white lines around the vehicle 1 and objects around the vehicle 1 (e.g., parked vehicles). The target parking position detection unit 57 detects the parking space around the vehicle 1 as a candidate parking position. The parking assistance control unit 51 sets the detected parking position candidate as the target parking position 31. The target trajectory generation unit 59 calculates the target parking path from the current position of the vehicle 1 in the vehicle coordinate system to the target parking position 31. The target trajectory generation unit 59 calculates the target vehicle speed profile, which is the target value of the vehicle speed of the vehicle 1 along the target parking path. The steering control unit 60 controls the steering actuator 21a so that the vehicle 1 travels along the target parking path. The vehicle speed control unit 61 controls the accelerator actuator 21b and brake actuator 21c so that the vehicle speed of the vehicle 1 changes according to the target vehicle speed profile. When the vehicle 1 reaches the target parking position 31 and parking assistance control is completed, the parking assistance control unit 51 activates the parking brake 20 and switches the shift position to the parking range.

[0030] While the target parking position detection unit 57 is attempting to detect a parking position candidate (i.e., while it is attempting to match a learned target with a surrounding target), the HMI control unit 50 displays a search screen on the HMI 13's display device to inform the user that the parking assist device 10 is attempting to detect a parking position candidate. Figure 9 is a schematic diagram of an example of a search screen. For example, the search screen 40d includes an captured image 41, an overhead image 42, a message display area 43, and an exit button 45. The message display area 43 may display notifications such as a visual message informing the user that the parking assist device 10 is attempting to detect a parking position candidate.

[0031] Furthermore, if the target parking position detection unit 57 does not perform a parking position candidate because the above-mentioned system conditions (for example, the shift position is not in the parking range or the user is wearing a seat belt) are not met, a different display (guidance) from the first help screen 40b or the second help screen 40c may be displayed on the display device of the HMI 13. For example, a notification such as a visual message informing that the system conditions are not met (for example, the shift position is in the parking range or the user is not wearing a seat belt) may be displayed in the message display area 43 of the search screen 40d.

[0032] When the target parking position detection unit 57 detects a parking position candidate (i.e., when it successfully detects a parking position candidate), the HMI control unit 50 displays the detection success screen 40a shown in Figure 4 on the display device of the HMI 13. On the other hand, if the target parking position detection unit 57 fails to detect a parking position candidate (i.e., fails to detect a parking position candidate), the HMI control unit 50 displays a detection failure screen on the HMI 13 display device to inform the user that a parking position candidate could not be detected. Figure 10 is a schematic diagram of an example of a detection failure screen. For example, the detection failure screen 40e includes an captured image 41, an overhead image 42, a message display area 43, a help button 49, and an exit button 45. The message display area 43 contains information indicating that the parking assist device 10 failed to detect a parking position candidate. No You may display a visual message or other notification to inform the user that this has happened. Furthermore, if the parking assist device 10 is set to automatic start mode, the HMI control unit 50 may automatically start displaying the detection success screen 40a when it successfully detects a parking position candidate. On the other hand, if the parking assist device 10 is set to automatic start mode, it does not need to automatically start displaying the detection failure screen 40e even if it fails to detect a parking position candidate. In this case, the HMI control unit 50 may start displaying the detection failure screen 40e, for example, when the user operates the parking switch 17.

[0033] When a user operates the help button 49, the HMI control unit 50 detects the operation of the help button 49 via a touch panel provided on the display device. When the help button 49 is operated, the HMI control unit 50 determines whether the reason why parking position candidates cannot be detected is due to user factors or environmental factors. User factors in the first and second support modes may include, for example, that the side mirrors are retracted, the doors are open, or the vehicle speed is above a threshold. Figures 11(a) and 11(b) are explanatory diagrams illustrating other examples of user factors in the first support mode. Figure 11(a) shows a scene in which the target parking position 31 is registered in the parking support device 10 in advance. Here, it is assumed that the vehicle 1 is driven in the direction of the arrow 37 and approaches the target parking position 31. The user drives the vehicle 1 along the parking path 36 by manual driving and parks it at the target parking position 31, and stores the objects detected around the target parking position 31 as learned objects in the storage device 19b. Figure 11(b) shows a scene in which the registered target parking position 31 is detected as a parking position candidate. Here, we assume that the vehicle 1 is driven in the direction of the arrow 38 to approach the target parking position 31. User factors may include the case where, when detecting a parking position candidate, the direction 38 in which the vehicle 1 approaches the parking position candidate (i.e., the target parking position 31) is different from the direction 37 in which the vehicle 1 approached the target parking position 31 when the vehicle 1 was parked at the target parking position 31 in order to store the target parking position 31 in the parking assist device 10. Specifically, this may be determined from the fact that the angle between direction 38 and direction 37 is greater than or equal to a predetermined value.

[0034] Furthermore, user factors in the first support mode may include the fact that the current position 33 of the vehicle 1 when detecting a candidate parking position (Figure 11(b)) is far from the parking path 36 when the vehicle 1 was parked at the target parking position 31 in order to store the target parking position 31 in the parking support device 10 (Figure 11(a)). Specifically, it may be determined that the distance between the parking path 36 and the current position 33 of the vehicle 1 is greater than or equal to a predetermined value. If the reason why a parking position candidate cannot be detected is a user factor, the HMI control unit 50 displays the first help screen 40b shown in Figure 5 on the display device of the HMI 13. The HMI control unit 50 may also display visual messages in the user factor display area 46 of the first help screen 40b that inform the user of the above user factors (when detecting a parking position candidate, the direction 38 in which the vehicle 1 approaches the parking position candidate is different from the direction 37 in which the vehicle 1 approached the target parking position 31 when registering the target parking position 31; when detecting a parking position candidate, the current position 33 is far from the parking route 36 when the target parking position 31 was registered; when the side mirrors are retracted; when the doors are open; and when the vehicle speed is above a threshold), such as "When approaching in the opposite direction to when registered," "When different from the position of the road surface traveled at the time of registration," "When the mirrors are folded," "When the doors are open," and "When the speed is high."

[0035] Environmental factors in the first and second support modes may include, for example, the inability to detect parking location candidates due to obstacles. The inability to detect parking location candidates due to obstacles may include, for example, in the first support mode, the presence of obstacles at the registered target parking location 31, or obstacles on the path from the vehicle 1 to the registered target parking location 31. Also, for example, in the second support mode, it may include obstacles in the available parking space around the vehicle 1, or obstacles on the path from the vehicle 1 to the available parking space. Environmental factors in the first support mode may include, for example, the inability of the positioning device 11 to measure the current position of the vehicle 1 when detecting parking position candidates. Environmental factors in the first support mode may also include, for example, the inability to detect parking position candidates due to a difference between the image in which objects present around the target parking position 31 are detected when storing learned object data in the storage device 19b (i.e., when registering the target parking position 31) and the image in which surrounding objects are detected when detecting parking position candidates.

[0036] If the reason why a parking position candidate cannot be detected is due to an environmental factor, the HMI control unit 50 displays the second help screen 40c shown in Figure 6 on the display device of the HMI 13. The HMI control unit 50 may also display visual messages in the environmental factor display area 48 of the first help screen 40b to inform the user of the above environmental factors (that a parking position candidate cannot be detected due to an obstacle, that the current position of the vehicle 1 cannot be measured, or that a parking position candidate cannot be detected due to a difference between the image in which the target was detected when the target parking position 31 was registered and the image in which the target was detected when the parking position candidate was detected), such as "The target parking position cannot be detected if there is an obstacle in the parking space or an obstacle between the vehicle and the parking space," "The target parking position cannot be detected if the GPS signal is continuously blocked," and "The target parking position may not be detected correctly if the image differs significantly from the image at the time of registration due to a change in ambient brightness, etc." Furthermore, if both user factors and environmental factors are present simultaneously, the HMI control unit 50 may prioritize displaying either the user factor or the environmental factor. For example, when the help button 49 is pressed, the HMI control unit 50 may prioritize displaying either the first help screen 40b or the second help screen 40c. User factors are relatively easy for users to resolve, whereas environmental factors are often difficult for users to resolve. Therefore, when both user and environmental factors are present, the HMI control unit 50 may, for example, prioritize displaying environmental factors over user factors. Conversely, the HMI control unit 50 may prioritize displaying user factors over environmental factors. If both user factors and environmental factors are present, both may be displayed. In the case of parking assistance control in the second assistance mode, the HMI control unit 50 does not need to display the first help screen 40b or the second help screen 40c. In this case, for example, the HMI control unit 50 may stop displaying the help button 49 on the detection failure screen 40e or disable the help button 49. The HMI control unit 50 may also display user factors and environmental factors in the message display area 43 of the detection failure screen 40e.

[0037] Figure 12 is a flowchart of the driving assistance method of the second embodiment. When parking assistance control starts, in step S10 the HMI control unit 50 displays the search screen 40d. In step S11 the parking assistance control unit 51 determines whether the system conditions are satisfied. If the system conditions are satisfied (step S11:Y), the process proceeds to step S13. If the system conditions are not satisfied (step S11:N), the process proceeds to step S12. In step S12 the HMI control unit 50 displays on the search screen 40d that the system conditions are not satisfied. After that, the process returns to step S11. In step S13 the target parking position detection unit 57 determines whether it has detected a parking position candidate. If a parking position candidate has been detected (step S13:Y), the process proceeds to step S14. If a parking position candidate cannot be detected (step S13:N), the process proceeds to step S18. In step S14 the HMI control unit 50 displays the detection success screen 40a.

[0038] In step S15, the HMI control unit 50 determines whether the exit button 45 has been pressed. If the exit button 45 has been pressed (step S15:Y), the process ends. If the exit button 45 has not been pressed (step S15:N), the process proceeds to step S16. In step S16, the HMI control unit 50 determines whether the parking start button 44 has been operated. If the parking start button 44 is not operated (step S16:N), the process returns to step S15. If the parking start button 44 is operated (step S16:Y), the process proceeds to step S17. In step S17, the parking assistance control unit 51 sets the detected parking position candidate as the target parking position 31. The target trajectory generation unit 59 calculates the target parking path from the current position 33 of the vehicle 1 to the target parking position 31. The steering control unit 60 and the vehicle speed control unit 61 perform parking assistance control of the vehicle 1 based on the calculated target parking path 34. The process then ends.

[0039] In step S18, the HMI control unit 50 displays the detection failure screen 40e. In step S19, the HMI control unit 50 determines whether or not the exit button 45 has been pressed. If the exit button 45 has been pressed (step S19: Y), the process ends. If the exit button 45 has not been pressed (step S19: N), the process proceeds to step S20. In step S20, the HMI control unit 50 determines whether the help button 49 has been pressed. If the help button 49 has not been pressed (step S20:N), the process returns to step S19. If the help button 49 has been pressed (step S20:Y), the process proceeds to step S21. In step S21, the HMI control unit 50 determines whether the reason why parking location candidates cannot be detected is a user factor or an environmental factor. If the reason why parking location candidates cannot be detected is a user factor (step S21:Y), the process proceeds to step S22. If the reason why parking location candidates cannot be detected is an environmental factor (step S21:N), the process proceeds to step S24.

[0040] In step S22, the HMI control unit 50 displays the first help screen 40b. In step S23, the HMI control unit 50 determines whether the back button 47 has been pressed. If the back button 47 is not pressed (step S23:N), the process returns to step S22. If the back button 47 is pressed (step S23:Y), the process returns to step S18. In step S24, the HMI control unit 50 displays the second help screen 40c. In step S25, the HMI control unit 50 determines whether the back button 47 has been pressed. If the back button 47 is not pressed (step S25:N), the process proceeds to step S24. If the back button 47 is pressed (step S25:Y), the process returns to step S18. In step S18, the HMI control unit 50 displays the detection failure screen 40e. In step S19, when the exit button 45 is pressed (step S19:Y), the process ends.

[0041] (Effects of the embodiment) (1) The controller 19 assists in parking the vehicle 1 at the target parking position. If the controller 19 cannot detect any candidate parking positions that are candidates for the target parking position around the vehicle 1, it displays the environmental factors on the display device if the reason for the inability to detect candidate parking positions is an environmental factor that depends on the environment of the vehicle 1, and displays the user factors on the display device if the reason for the inability to detect candidate parking positions is a user factor that depends on the user. This makes it easier for the user to deal with situations where the target parking position cannot be detected.

[0042] (2) The controller 19 determines whether predetermined system conditions for performing parking assistance control are met, and if the system conditions are met, it detects a parking position candidate. If the system conditions are not met, it may display a different display on the display device than the display of environmental factors and the display of user factors. This allows the detection process of the target parking position to be omitted if the system conditions are not met, and the user to be notified that the system conditions are not met.

[0043] (3) In the first support mode of driving support control, the controller 19 may store data representing the relative positional relationship between the target parking position and the targets surrounding the target parking position as learned target data in a storage device, detect surrounding targets that are targets around the vehicle 1, and detect parking position candidates around the vehicle 1 based on the learned target data of the targets surrounding the vehicle 1 and the surrounding targets. This allows the user to use parking support control that assists the vehicle 1 in parking to a pre-registered target parking position.

[0044] (4) In the first support mode of driving support control, when the controller 19 can measure the current position of the vehicle 1 when detecting a pre-stored parking position candidate, it may detect objects present around the current position as surrounding objects. Environmental factors may include the inability to measure the current position of the vehicle 1. This allows the user to be informed that the target parking position cannot be detected because the current position of the vehicle 1 cannot be measured.

[0045] (5) In the first support mode of driving support control Te Yu The error factor may include the case where the first direction in which the vehicle 1 approaches a parking position candidate when detecting a pre-stored parking position candidate is different from the second direction in which the vehicle 1 approaches the target parking position when parking the vehicle 1 at the target parking position in order to store the learned target data in the storage device. This allows the user to be informed that the target parking position cannot be detected because the direction in which the vehicle 1 approaches the target parking position is different when registering the target parking position and when detecting a registered target parking position.

[0046] (6) In the first support mode of driving support control, the controller 19 may measure the current position of the vehicle 1 when detecting a pre-stored parking position candidate. User factors may also include the case where the measured current position is more than a predetermined distance away from the parking route that the vehicle 1 traveled to the target parking position when the vehicle 1 was parked at the target parking position in order to store the learned target data in the storage device. This allows the user to be notified that the target parking position cannot be detected because it is far from the parking route used when registering the target parking position.

[0047] (7) Environmental factors may include the inability to detect the target parking position due to differences between the image used to detect objects surrounding the target parking position when storing learned target data in a memory device and the image used to detect surrounding objects. This allows the user to be notified that the target parking position cannot be detected because the image used to detect objects differs significantly between when registering the target parking position and when detecting a registered target parking position.

[0048] (8) In the second support mode of driving assistance control, the controller 19 may detect a suitable parking space around the vehicle 1 as a target parking position based on the detection results obtained by the sensor from detecting white lines or objects around the vehicle 1. This allows the user to use parking assistance control that assists the vehicle 1 in parking at a target parking position that has not been registered in advance. (9) Environmental factors may include the inability to detect the target parking position due to obstacles. This allows the user to be informed that the target parking position cannot be detected due to obstacles.

[0049] (10) If environmental factors and user factors are present simultaneously, the controller 19 may display either one of the environmental factors or the user factors and not the other. This allows the controller to determine which factor to prioritize informing the user of, according to the characteristics of the factor that prevents the detection of the target parking position. For example, it's possible to display environmental factors but not user-related factors. This allows for prioritizing and informing users of environmental factors that are difficult for them to resolve. [Explanation of symbols]

[0050] 1...Vehicle, 10...Parking assist system, 19...Controller

Claims

1. A parking assistance method that assists in parking one's own vehicle in a target parking position, Prior to this, data representing the relative positional relationship between the target parking location and the targets surrounding it is stored in a memory device as learned target data. The system detects surrounding targets, which are objects present around the vehicle. Based on the learned target data of targets present around the vehicle and the surrounding targets, candidate parking locations that are candidates for the target parking location are detected around the vehicle. If no parking location candidates existing around the vehicle can be detected, and the reason for the inability to detect the parking location candidates is an environmental factor that depends on the environment of the vehicle, the environmental factor will be displayed on the display device; and if the reason for the inability to detect the parking location candidates is a user factor that depends on the user, the user factor will be displayed on the display device. A parking assistance method characterized by the following features.

2. Determine whether predetermined system conditions are met for performing parking assistance control to assist in parking the vehicle at the target parking position. If the system conditions are met, the parking position candidate is detected; if the system conditions are not met, a display different from the display of environmental factors and the display of user factors is displayed on the display device. The parking assistance method according to feature 1.

3. When detecting the pre-stored parking position candidates, if the current position of the vehicle can be measured, the objects present around the current position are detected as the surrounding objects. The parking assistance method according to claim 1, characterized in that the aforementioned environmental factors include the inability to measure the current position of the vehicle.

4. The parking assistance method according to claim 1, characterized in that the user factor includes a difference between a first direction in which the vehicle approaches the parking position candidate when detecting the pre-stored parking position candidate, and a second direction in which the vehicle approaches the target parking position when parking the vehicle at the target parking position in order to store the learned target data in the storage device.

5. When detecting the pre-stored parking position candidates, the current position of the vehicle is measured. The parking assistance method according to claim 1, characterized in that the user factor includes the measured current position being at least a predetermined distance from the parking path the vehicle traveled to the target parking position when the vehicle was parked at the target parking position in order to store the learned target data in the storage device.

6. The parking assistance method according to any one of claims 1 to 5, characterized in that the environmental factors include the inability to detect the target parking position due to a difference between the image in which objects present around the target parking position are detected when storing the learned target data in the storage device and the image in which surrounding objects are detected.

7. The parking assistance method according to claim 1 or 2, characterized in that, based on the detection results obtained by detecting white lines or objects around the vehicle using a sensor, a parking space available around the vehicle is detected as the target parking position.

8. The parking assistance method according to any one of claims 1 to 5, characterized in that the aforementioned environmental factors include the inability to detect the target parking position due to an obstacle.

9. The parking assistance method according to any one of claims 1 to 5, characterized in that, when the aforementioned environmental factors and the aforementioned user factors are present simultaneously, one of the environmental factors and the aforementioned user factors is displayed and the other is not displayed.

10. The parking assistance method according to claim 9, characterized in that the environmental factors are displayed and the user factors are not displayed.

11. A parking assist device that assists in parking the vehicle at a target parking position, Memory device and Display device and A controller that, in advance stores data representing the relative positional relationship between objects present around the target parking position and the target parking position as learned object data in the storage device, detects surrounding objects which are objects present around the vehicle, detects candidate parking positions which are candidates for the target parking position present around the vehicle based on the learned object data of objects present around the vehicle and the surrounding objects, and if no candidate parking positions present around the vehicle can be detected, displays the environmental factors on the display device if the reason for the inability to detect candidate parking positions is an environmental factor which is a factor dependent on the environment of the vehicle, and displays the user factors on the display device if the reason for the inability to detect candidate parking positions is a user factor which is a factor dependent on the user, A parking assistance device characterized by being equipped with the following features.

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