Parking assistance method and parking assistance device

Abstract

In this parking assistance method, when registering learned landmark data to a storage device, in a case where a limitation factor exists, the learned landmark data is not registered to the storage device (S1: N), and, if an environment factor which depends on an environment of own vehicle exists as the limitation factor, the environment factor is displayed on a display device (S5), whereas if a user factor which depends on a user exists as the limitation factor, 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 parking assistance control for registering a target parking position in the host vehicle in advance and assisting parking at the registered target parking position, when a situation occurs where the target parking position cannot be registered, there is a risk that the user cannot cope with the situation where the target parking position cannot be registered because the user cannot determine the cause. An object of the present invention is to facilitate the user's coping with a situation where the target parking position cannot be registered when the target parking position cannot be registered in the host vehicle.

Means for Solving the Problems

[0005] A parking assistance method is provided that assists in parking the vehicle at a target parking position. The parking assistance method includes: detecting objects present around the target parking position in advance and registering data representing the relative positional relationship between the detected objects and the target parking position as learned object data in a storage device; detecting the positions of surrounding objects, which are objects present around the vehicle, when moving the vehicle to the target parking position after registering the learned object data in the storage device; calculating the relative positional relationship between the target parking position and the current position of the vehicle based on the learned object data and the positions of the surrounding objects; calculating the driving trajectory from the current position of the vehicle to the target parking position based on the calculated relative positional relationship; and assisting in parking the vehicle at the target parking position based on the driving trajectory. In the parking assistance method, when registering the learned object data in the storage device, if limiting factors exist, the learned object data is not registered in the storage device. Furthermore, if environmental factors dependent on the vehicle's environment exist as limiting factors, the environmental factors are displayed on the display device, and if user factors dependent on the user exist as limiting factors, the user factors are displayed on the display device. [Effects of the Invention]

[0006] According to the present invention, when a target parking position for parking one's vehicle cannot be registered, it becomes easier for the user to deal with the situation in which a target parking position cannot be registered. The objectives and advantages of the present invention are embodied and achieved using the elements and combinations thereof set forth in the claims. Both the general description above and the detailed description below are merely illustrative and descriptive, and should be understood not to limit the invention in any way that would be limited by the claims. [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 parking assist control. [Figure 3] This is a schematic diagram of an example of a registration guidance screen. [Figure 4]This is a schematic diagram of an example of the first help screen. [Figure 5] This is a schematic diagram of an example of the second help screen. [Figure 6] This is a flowchart of the driving assistance method according to the first embodiment. [Figure 7] Figure 1 is a block diagram showing an example of the controller's functional configuration. [Figure 8] This is a schematic diagram of an example of a screen for determining whether registration is possible or not. [Figure 9] 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.

[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 assistance control by the controller 19 will be explained. Figures 2(a) and 2(b) are schematic diagrams illustrating the parking assistance control. When using the parking assistance control, the target parking position 31 in which the vehicle 1 should be parked is registered in advance with the parking assistance device 10. Specifically, landmarks existing around the target parking position 31 are extracted and stored (registered) in the storage device 19b in advance. In the following explanation, landmarks around the target parking position 31 stored in the storage device 19b will be referred to as "learned landmarks". In Figure 2(a), the circle plots schematically represent learned landmarks. When registering the target parking position 31 with the parking assistance device 10, the user performs an operation to instruct the registration of the target parking position 31 (hereinafter sometimes referred to as the "registration operation"). For example, the registration operation may be performed by operating (pressing) the parking switch 17 when the shift position is in the parking range. The controller 19 may automatically start the target parking position 31 registration process when the shift position changes to the parking range. The parking assist device 10 may be switchable between an automatic start mode, which automatically starts the registration process for the target parking position 31 when the shift position changes to the parking range, and a manual start mode, which starts the registration process for the target parking position 31 when the parking switch 17 is operated while the shift position is in the parking range.

[0013] For example, when a user manually parks their vehicle 1 at the target parking position 31, the controller 19 detects objects around the vehicle 1 using 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, specifically edge points 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 the learned object target with respect to the target parking position 31 may be memorized. For example, the controller 19 can acquire the position of the learned object target detected when the host vehicle 1 parks at the target parking position 31 as the relative position of the learned object target with respect to the target parking position 31. The coordinates of the learned object target and the target parking position 31 in a coordinate system (hereinafter referred to as "map coordinate system") with a fixed point as the reference point may be memorized.

[0014] FIG. 2(b) is an explanatory diagram of an example of the process during parking support implementation. The controller 19 starts the parking support control of the host vehicle 1 when an operation by the user (hereinafter sometimes referred to as "activation operation") instructing the activation of the parking support control of the host vehicle 1 is performed. For example, the activation operation may be an operation of the parking switch 17 by the user. Also, the controller 19 may automatically start the parking support control when the host vehicle 1 approaches the registered target parking position 31.

[0015] When the parking support control starts, the controller 19 extracts object targets around the host vehicle 1 with the external sensor 15. In the following description, the object targets around the host vehicle 1 extracted during parking support implementation are referred to as "surrounding object targets". In FIG. 2(b), the triangular plots represent the surrounding object targets. The controller 19 detects the target parking position 31 by matching the learned object target and the surrounding object target and associating the same feature points with each other. Based on the relative positional relationship between the surrounding object target detected during parking support implementation and the host vehicle 1, and the relative positional relationship between the learned object target associated with the surrounding object target and the target parking position 31, the relative position of the host vehicle 1 with respect to the target parking position 31 is calculated.

[0016] 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. The controller 19 calculates a target parking path 34 from the vehicle's current position 33 to the target parking position 31, based on the vehicle's relative position to the target parking position 31. The controller 19 then performs parking assistance control for the vehicle based on the calculated target parking path 34.

[0017] When registering learned target data for the target parking position 31 where the vehicle 1 should be parked in the storage device 19b, the controller 19 determines whether or not there are limiting factors that prevent the registration of the learned target data in the storage device 19b. If there are no limiting factors, the controller 19 displays a registration guidance screen on the HMI 13's display device prompting the user to register the target parking position 31. Figure 3 is a schematic diagram of an example of a registration guidance screen. For example, the registration guidance 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 registration button 44, and an exit button 45. The message display area 43 of the registration guidance screen 40a may display notifications, such as a visual message informing the user that they can register a target parking location. When the user operates the registration button 44 or the end button 45 displayed on the display device, the touch panel provided on the display device detects these operations.

[0018] When the registration button 44 is pressed, the controller 19 registers the learned target data of the learned targets detected around the target parking position 31 into the storage device 19b. When the exit button 45 is pressed, the controller 19 cancels the registration process for the target parking position 31. The same applies when the exit button 45 on the registration feasibility determination screen 40d, shown in Figure 8 and described later, is pressed. On the other hand, if there is a limiting factor that prevents the learned target data from being registered in the storage device 19b, the controller 19 determines whether the limiting factor is a user-dependent factor or an environmental factor that depends on the environment of the vehicle 1.

[0019] If the limiting factor is a user-related issue, the controller 19 displays a first help screen on the HMI 13's display device to inform the user of the user-related issue. Figure 4 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-related issue display area 46 that displays the user-related issue, 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.

[0020] If the limiting factor 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 5 is a schematic diagram of an example of the second help screen. For example, the second help screen 40c includes an overview image 42, an environmental factor display area 48 that displays the environmental factor, and a back button 47. When the user operates the back button 47, the controller 19 stops displaying the second help screen 40c.

[0021] (operation) Figure 6 is a flowchart of the driving assistance method according to the first embodiment. In step S1, the controller 19 determines whether or not the target parking position 31 can be registered (i.e., whether or not there is a limiting factor preventing the registration of the target parking position 31). If the target parking position 31 can be registered (step S1:Y), the process proceeds to step S2. If the target parking position 31 cannot be registered (step S1:N), the process proceeds to step S3. In step S2, the controller 19 displays the registration guidance screen 40a on the display device. In step S3, the controller 19 determines whether or not the limiting factor preventing the registration of the target parking position 31 is a user factor. If the limiting factor is a user factor (step S3:Y), the process proceeds to step S4. If the limiting factor is an environmental factor (step S3:N), the process proceeds to step S5. In step S4, the controller 19 displays the first help screen 40b on the display device. In step S5, the controller 19 displays the second help screen 40c on the display device.

[0022] (Second Embodiment) Figure 7 is a block diagram of an example of the functional configuration of the controller 19. When the parking assist device 10 is set to manual start mode, the HMI control unit 50 detects that the parking switch 17 has been operated while the shift position is in the parking range, and outputs a map generation command to the map generation unit 55 to store the learned target data in the storage device 19b. Also, when the parking assist device 10 is set to automatic start mode, the HMI control unit 50 detects that the shift position has changed to the parking range, and outputs a map generation command to the map generation unit 55. 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.

[0023] 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.

[0024] When the map generation unit 55 receives a map generation command from the HMI control unit 50 (i.e., when the registration process for the target parking position 31 begins), it performs a determination process to determine whether or not to register the learned target data. In the determination process to determine whether or not to register the learned target data in the storage device 19b, the map generation unit 55 determines whether or not to register the learned target data in the storage device 19b (i.e., whether or not there are limiting factors that prevent the learning target data from being registered in the storage device 19b). For example, the map generation unit 55 determines whether or not user factors exist as limiting factors. User factors may be, for example, when the vehicle 1 is parked at the target parking position 31 in order to register learned target data in the storage device 19b, at least one of the following conditions (A) to (E) must be met. (A) The side mirrors were folded in. (B) The door was open. (C) Wheel slippage detected. (D) The vehicle speed of vehicle 1 was above the threshold (e.g., 30 km / h). (E) The mileage was insufficient.

[0025] Furthermore, the map generation unit 55 determines, for example, whether or not environmental factors exist as limiting factors. Environmental factors may include, for example, at least one of the following: when an image is captured for extracting learned targets, the number of feature points around the target parking position 31 is less than a predetermined value; the lighting conditions around the target parking position 31 are less than predetermined conditions; or the clearance around the target parking position 31 is less than a predetermined distance. Ambient lighting conditions may be defined as the ambient brightness being below a predetermined value. Clearance may refer to, for example, the distance between the edge of the vehicle 1 and an obstacle when registering the target parking position 31, or the distance between the edge of the parking space and an obstacle.

[0026] While the map generation unit 55 is performing the registration feasibility determination process, the HMI control unit 50 displays a registration feasibility determination screen on the HMI 13's display device to inform the user that the registration process for the target parking position 31 is underway. Figure 8 is a schematic diagram of an example of the registration feasibility determination screen. For example, the registration feasibility determination screen 40d includes an captured image 41, an overhead image 42, a message display area 43, a help button 49, and an exit button 45. For example, the message display area 43 may display a visual message or other notification prompting the user to press the help button 49 to check instructions regarding the registration of the target parking location 31 (e.g., precautions for registering the target parking location 31). When a user operates the help button 49, the HMI control unit 50 detects the operation of the help button 49 via the touch panel provided on the display device.

[0027] If the help button 49 is pressed before the registration eligibility determination process is completed, the HMI control unit 50 displays the first help screen 40b shown in Figure 4 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 to inform the user of the above user factors (A) to (E), such as "When the mirrors are closed," "When the doors are opened," "When the wheels are slipping," "When the speed is too high," and "When the mileage is insufficient."

[0028] On the other hand, when the registration feasibility determination process is completed and the map generation unit 55 determines that it will register the learned target data in the storage device 19b, the HMI control unit 50 displays the registration guidance screen 40a shown in Figure 3 on the display device of the HMI 13. When the registration button 44 is operated, the map generation unit 55 stores the learned target data as map data 56 in the storage device 19b. Furthermore, the generation of trained target data may be performed in parallel with the registration feasibility determination process, or the generation of trained target data may be started after it has been determined that the trained target data should be registered in the storage device 19b. For example, the map generation unit 55 receives object data and the vehicle's own position on the map coordinate system synchronized with the object data from the object 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, when the vehicle 1 is located at the target parking position 31, the vehicle's own position calculated by the self-position calculation unit 53 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. It generates trained target data that includes this relative position data and feature data.

[0029] Furthermore, if the registration feasibility determination process is completed and the map generation unit 55 determines that it will not register the learned target data in the storage device 19b (i.e., if a limiting factor exists), the HMI control unit 50 continues to display the registration feasibility determination screen 40d as illustrated in Figure 8. When the help button 49 is operated, the HMI control unit 50 determines whether the limiting factor is a user factor or an environmental factor. If the limiting factor is a user factor, the HMI control unit 50 displays the first help screen 40b shown in Figure 4 on the display device of the HMI 13. If the limiting factor is an environmental factor, the HMI control unit 50 displays the second help screen 40c shown in Figure 5 on the display device of the HMI 13. The HMI control unit 50 may also display visual messages in the environmental factors display area 48 of the second help screen 40c to inform the user of the above-mentioned environmental factors (insufficient number of feature points around the target parking position 31, inappropriate lighting conditions around the target parking position 31, insufficient clearance around the target parking position 31), such as "When there are no or few road surface patterns," "When there are shadows on the road surface or the surroundings are dark," and "When an obstacle is detected at an extremely close position while moving."

[0030] 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.

[0031] In the first help screen 40b and the second help screen 40c, when the user operates the back button 47, the HMI control unit 50 determines whether the limiting factor has been resolved. If the limiting factor has been resolved, the HMI control unit 50 may display the registration guidance screen 40a on the display device of the HMI 13. If the limiting factor has not been resolved, the HMI control unit 50 may display the registration feasibility determination screen 40d on the display device of the HMI 13. Furthermore, the HMI control unit 50 may automatically display the registration guidance screen 40a without requiring the user to operate the back button 47 once the limiting factor has been resolved.

[0032] Furthermore, even if the limiting factor is resolved when the user operates the back button 47, the HMI control unit 50 may display the registration guidance screen 40a on the condition that the operation of parking the vehicle 1 at the target parking position 31 is redone after the map generation unit 55 determines that it will not register the learned target data in the storage device 19b. If the operation of parking the vehicle 1 at the target parking position 31 is not redone after the map generation unit 55 determines that it will not register the learned target data in the storage device 19b, the HMI control unit 50 may display the registration feasibility determination screen 40d on the display device of the HMI 13.

[0033] For example, if the image of the surroundings of the vehicle 1 generated by the image conversion unit 52 (i.e., the image from which the learned targets are extracted) is problematic due to the existence of limiting factors, and the learned target data cannot be registered in the storage device 19b, the operation of parking the vehicle 1 at the target parking position 31 may be repeated before the registration guidance screen 40a is displayed. For example, if the surrounding image is not suitable for extracting feature points, the operation of parking the vehicle 1 at the target parking position 31 may be repeated before the registration guidance screen 40a is displayed. For example, if the surrounding image is captured with the side mirrors retracted, the doors open, or the vehicle speed is too high, or if the driving distance when capturing the surrounding image is insufficient, problems will occur in the surrounding image generated by the image conversion unit 52, requiring the vehicle 1 to be parked at the target parking position 31 again. The same applies if the number of feature points around the target parking position 31 is insufficient, or if the lighting conditions around the target parking position 31 are inappropriate.

[0034] On the other hand, even if there are no problems with the surrounding image of the vehicle 1 generated by the image conversion unit 52, if the map generation unit 55 determines that it does not register the learned target data in the storage device 19b, the registration guidance screen 40a may be displayed without having to repeat the operation of parking the vehicle 1 at the target parking position 31 once the limiting factor is resolved. For example, if, after parking the vehicle 1 at the target parking position 31 in order to register the learned target data in the storage device 19b, the side mirrors are folded in or the doors are opened, the registration guidance screen 40a may be displayed without requiring the vehicle 1 to be parked at the target parking position 31 again once these user factors are resolved. Also, for example, if, after the map generation unit 55 has determined that it is not necessary to register the learned target data in the storage device 19b, the obstacles around the target parking position 31 are removed and the environmental factor of insufficient clearance around the target parking position 31 is resolved, the registration guidance screen 40a may be displayed without requiring the vehicle 1 to be parked at the target parking position 31 again.

[0035] Refer to Figure 7. When the HMI control unit 50 detects a user's operation to activate 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. When the parking assistance control unit 51 receives a control start command from the HMI control unit 50, it 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 assistance control unit 51 executes parking assistance control. The parking assistance control unit 51 may also automatically start parking assistance control when the vehicle 1 approaches the registered target parking position 31. When the parking assistance control unit 51 starts parking assistance control, it outputs a parking position calculation command to the target parking position detection unit 57. Upon receiving the parking position calculation command, the target parking position detection unit 57 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.

[0036] The target parking position detection unit 57 detects the target parking position 31 by matching learned targets with surrounding targets and associating targets with the same feature points. In other words, it determines whether or not the target parking position 31 can be detected based on whether or not the matching between the learned targets and surrounding targets is successful. If the matching is successful (i.e., the target parking position 31 is detected), the target parking position detection unit 57 calculates the relative position of the vehicle 1 with respect to the target parking position 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 position 31. The target trajectory generation unit 59 calculates a 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 a 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.

[0037] Figure 9 is a flowchart of the driving assistance method of the second embodiment. When the registration process for the target parking position 31 is started, in step S10 the HMI control unit 50 displays the registration feasibility determination screen 40d. In step S11 the HMI control unit 50 determines whether the registration feasibility determination process by the map generation unit 55 has been completed. If the registration feasibility determination process is completed (step S11:Y), the process proceeds to step S14. If the registration feasibility determination process is not completed (step S11:N), the process proceeds to step S12. In step S12, the HMI control unit 50 determines whether the help button 49 has been pressed. If the help button 49 has been pressed (step S12:Y), the process proceeds to step S13. If the help button 49 has not been pressed (step S12:N), the process returns to step S10. In step S13, the HMI control unit 50 displays the first help screen 40b. After that, the process returns to step S10.

[0038] If the registration feasibility determination process determines that the learned target data can be registered (step S14:Y), the process proceeds to step S21. If the learned target data cannot be registered (step S14:N), the process proceeds to step S15. In step S15, the HMI control unit 50 determines whether the help button 49 has been operated. If the help button 49 has not been operated (step S15:N), the process returns to step S15. If the help button 49 has been operated (step S15:Y), the process proceeds to step S16. In step S16, the HMI control unit 50 determines whether the limiting factor preventing the registration of the learned target data is a user factor. If the limiting factor is a user factor (step S16:Y), the process proceeds to step S17. If the limiting factor is an environmental factor (step S16:N), the process proceeds to step S18. In step S17, the HMI control unit 50 displays the first help screen 40b. The process then proceeds to step S19. In step S18, the HMI control unit 50 displays the second help screen 40c. The process then proceeds to step S19.

[0039] In step S19, the HMI control unit 50 determines whether the back button 47 on the first help screen 40b or the second help screen 40c has been operated. If the back button 47 has not been operated (step S19:N), the process returns to step S19. If the back button 47 has been operated (step S19:Y), the process proceeds to step S20. In step S20, the HMI control unit 50 determines whether the limiting factor has been resolved. If the limiting factor has not been resolved (step S20:N), the process returns to step S10. If the limiting factor has been resolved (step S20:Y), the process proceeds to step S21.

[0040] In step S21, the HMI control unit 50 displays the registration guidance screen 40a on the display device of the HMI 13. In step S22, the HMI control unit 50 determines whether the exit button 45 has been pressed. If the exit button 45 has been pressed (step S22:Y), the registration process for the target parking position 31 is completed. If the exit button 45 has not been pressed (step S22:N), the process proceeds to step S23. In step S23, the HMI control unit 50 determines whether the registration button 44 has been pressed. If the registration button 44 has not been pressed (step S23:N), the process returns to step S22. If the registration button 44 has been pressed (step S23:Y), the process proceeds to step S24. In step S24, the map generation unit 55 stores the learned target data in the storage device 19b. After that, the registration process for the target parking position 31 is completed.

[0041] (Effects of the embodiment) (1) When registering learned target data in the storage device 19b, the controller 19 determines whether there are any limiting factors that prevent the registration of learned target data in the storage device 19b. If limiting factors exist, the controller 19 does not register the learned target data in the storage device 19b. Furthermore, if there are environmental factors that depend on the vehicle's environment as limiting factors, the controller displays the environmental factors on the display device. If there are user factors that depend on the user as limiting factors, the controller displays the user factors on the display device. This allows the user to determine the limiting factors that prevent the registration of learned target data when it is not possible to register the learned target data, making it easier for the user to deal with situations where the target parking position cannot be registered.

[0042] (2) When 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 display the other. This allows the controller to decide which of the environmental factors or the user factors to prioritize informing the user, depending on the characteristics of the factors that prevent the registration of learned target data. For example, the controller 19 may prioritize displaying environmental factors over user factors. This allows the controller to prioritize informing users of environmental factors that are difficult for them to resolve. (3) Environmental factors may include at least one of the following: the number of feature points present around the target parking position is less than a predetermined value; the lighting conditions around the target parking position are less than a predetermined condition; or the clearance around the target parking position is less than a predetermined distance. This allows the user to be informed of which environmental factors prevent the registered learned target data from being stored in the storage device 19b.

[0043] (4) The user factor is that when the vehicle is driven near the target parking position in order to register the learned target data in the storage device, at least one of the following conditions (A) to (D) is met. (A) The side mirrors of vehicle 1 were folded in. (B) The door of vehicle 1 was open. (C) Wheel slippage of vehicle 1 was detected. (D) The vehicle speed of vehicle 1 was above the threshold. This allows the user to be informed of the user-related factors that prevent the learned target data from being registered in the storage device 19b.

[0044] (5) When the limiting factor is resolved, the controller 19 may display a notification on the display device prompting the user to register the learned target data in the storage device 19b. This allows the learned target data to be registered in the storage device 19b immediately when the limiting factor is resolved and it becomes possible to register the learned target data in the storage device 19b. (6) If the limiting factor is resolved after the vehicle has been parked again at the target parking position, a notification may be displayed on the display device prompting the user to register the learned target data in the storage device 19b. This allows the system to reacquire the information necessary to generate the learned target data after the limiting factor has been resolved, and then register the learned target data in the storage device 19b.

[0045] All examples and conditional terms set forth herein are intended for educational purposes to help the reader understand the concepts given by the inventors for the advancement of the invention and the art, and should be interpreted without limitation to the examples and conditions specifically described herein, as well as the configuration of examples relating to demonstrating the superiority and inferiority of the invention. Although embodiments of the invention are described in detail, it should be understood that various changes, substitutions, and modifications are possible without departing from the spirit and scope of the invention. [Explanation of symbols]

[0046] 1...Own vehicle, 10...Parking assist device, 11...Positioning device, 12...Map database, 13...Human-machine interface, 14...Shift switch, 15...External environment sensor, 16...Vehicle sensor, 17...Parking switch, 19...Controller, 19a...Processor, 19b...Storage device, 20...Parking brake, 21a...Steering actuator, 21b...Accelerator actuator, 21c...Brake actuator, 50...HMI control unit, 51...Parking assist control unit, 52...Image conversion unit, 53...Self-position calculation unit, 54...Target detection unit, 55...Map generation unit, 56...Map data, 57...Target parking position detection unit, 59...Target trajectory generation unit, 60...Steering control unit, 61...Vehicle speed control unit

Claims

1. A parking assistance method that assists in parking one's own vehicle in a target parking position, The system detects objects existing around the target parking position in advance, and registers data representing the relative positional relationship between the detected objects and the target parking position as learned object data in the storage device. When moving the vehicle to the target parking position after registering the learned target data in the storage device, the positions of surrounding targets, which are targets present around the vehicle, are detected. Based on the learned target data and the positions of the surrounding targets, the relative positional relationship between the target parking position and the current position of the vehicle is calculated. Based on the calculated relative positional relationship, the driving trajectory from the current position of the vehicle to the target parking position is calculated, This includes assisting in parking the vehicle at the target parking position based on the aforementioned driving trajectory, When registering the learned target data in the storage device, if limiting factors exist, the learned target data will not be registered in the storage device. Furthermore, if the limiting factors include environmental factors that depend on the environment of the vehicle, these environmental factors will be displayed on the display device. If the limiting factors include user factors that depend on the user, these user factors will be displayed on the display device. A parking assistance method characterized by the following features.

2. The parking assistance method according to claim 1, characterized in that, when the environmental factors and the user factors are present simultaneously, either one of the environmental factors or the user factors is displayed, and the other is not displayed.

3. The parking assistance method according to claim 2, characterized in that the environmental factors are displayed with priority over the user factors.

4. The parking assistance method according to any one of claims 1 to 3, characterized in that the environmental factors include at least one of the following: the number of feature points present around the target parking position is less than a predetermined value; the lighting conditions around the target parking position are less than a predetermined condition; or the clearance around the target parking position is less than a predetermined distance.

5. The aforementioned user factors occur when the vehicle is driven near the target parking position in order to register the learned target data in the storage device, under the following conditions (A) to (D): (A) The side mirrors of the vehicle were retracted. (B) The door of the vehicle in question was open. (C) The wheels of the vehicle slipped, (D) The vehicle speed of the vehicle in question was above the threshold, A parking assistance method according to any one of claims 1 to 3, characterized in that it satisfies at least one of the following conditions.

6. The parking assistance method according to any one of claims 1 to 3, characterized in that, when the limiting factors are resolved, a notification prompting the user to register the learned target data in the storage device is displayed on the display device.

7. The parking assistance method according to any one of claims 1 to 3, characterized in that, after the operation of parking the vehicle at the target parking position is repeated and the limiting factor is resolved, a notification prompting the user to register the learned target data in the storage device is displayed on the display device.

8. A parking assist device that assists in parking the vehicle at a target parking position, A sensor for detecting targets around the vehicle, Memory device and Display device and The system includes a controller that, in advance, detects objects present around the target parking location, registers data representing the relative positional relationship between the detected objects and the target parking location as learned object data in the storage device, detects the positions of surrounding objects (objects present around the vehicle) when moving the vehicle to the target parking location after registering the learned object data in the storage device, calculates the relative positional relationship between the target parking location and the current position of the vehicle based on the learned object data and the positions of the surrounding objects, calculates a driving trajectory from the current position of the vehicle to the target parking location based on the calculated relative positional relationship, and assists in parking the vehicle at the target parking location based on the driving trajectory, wherein the controller, When registering the learned target data in the storage device, if limiting factors exist, the learned target data will not be registered in the storage device. Furthermore, if the limiting factors include environmental factors that depend on the environment of the vehicle, these environmental factors will be displayed on the display device. If the limiting factors include user factors that depend on the user, these user factors will be displayed on the display device. A parking assistance device characterized by the following features.

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