Parking assistance method and parking assistance device

Abstract

In a state where one of a first assistance mode (ST01) in which a pre-registered parking position candidate is set to a target parking position and parking is assisted and a second assistance mode (ST02) in which a target parking position is set without using the pre-registered parking position candidate and parking is assisted is selected, this parking assistance method for assisting the host vehicle in parking at the target parking position permits the switch from the one mode to the other mode (C1, C3) when the host vehicle is stopping at the time of receiving a switch instruction to the other mode, and does not permit the switch from the one mode to the other mode (C2, C4) when the host vehicle does not stop at the time of receiving the switch instruction.

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 a parking control device that selects a first automatic parking mode and a second automatic parking mode according to the shift position.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a parking assistance device that assists the parking of the host vehicle to a target parking position has a plurality of different assistance modes, it is preferable that the user can arbitrarily switch between these assistance modes. However, there is a risk that the user's attention to the surroundings may be neglected due to the operation of switching the assistance mode. An object of the present invention is to improve the safety when switching assistance modes in a parking assistance device having a plurality of different assistance modes.

Means for Solving the Problems

[0005] According to one aspect of the present invention, a parking assistance method is provided that assists in parking the vehicle at a target parking position. The parking assistance method includes a first assistance mode that assists in parking by setting a pre-registered parking position candidate as the target parking position, and a second assistance mode that assists in parking by setting a target parking position without using a pre-registered parking position candidate. When one of these modes is selected and a command to switch to the other mode is received, the system allows switching from one mode to the other mode if the vehicle is stopped. However, when the command to switch is received and the vehicle is not stopped, the system does not allow switching from one mode to the other mode. [Effects of the Invention]

[0006] According to the present invention, in a parking assist system equipped with multiple different assist modes, safety during switching between assist modes can be improved. 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 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 state transition diagram illustrating an example of the operating state of the parking assist device according to the first embodiment. [Figure 5] Figure 1 is a block diagram showing an example of the controller's functional configuration. [Figure 6] (a) to (c) are schematic diagrams illustrating the parking assistance screen in the first assistance mode. [Figure 7] (a) to (c) are schematic diagrams illustrating the parking assistance screen in the second assistance mode. [Figure 8] This is a flowchart illustrating an example of the operation at the start of parking assist control. [Figure 9] This is a state transition diagram illustrating an example of the operating state of the parking assist device 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 switching switch (mode switching SW) 18 is a switch for switching the control mode of the parking assistance control by the parking assistance device 10. For example, a touch panel may be provided on the display device of the HMI 13, and the touch panel may detect when the user touches the image of the mode switching switch 18 displayed on the display device. The mode switching switch 18 is not limited to the touch panel, but may be installed anywhere in the vehicle that the user can touch.

[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 described. For example, the controller 19 may perform parking assistance control that assists parking by setting a pre-registered parking position candidate as the target parking position. In the following description, the control mode of parking assistance control that assists parking by setting a pre-registered parking position candidate as the target parking position may be referred to as the "first assistance mode". Alternatively, the controller 19 may perform parking assistance control that assists parking by setting a target parking position without using a pre-registered parking position candidate. In the following description, the control mode of parking assistance control that assists parking by setting a target parking position without using a pre-registered parking position candidate may be referred to as the "second assistance mode".

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

[0014] For example, when the host vehicle 1 is located near the target parking position 31 (for example, when the user manually parks the host vehicle 1 at the target parking position 31), the controller 19 detects objects around the host vehicle 1 with the external sensor 15 and stores them as learned objects. For example, objects may be detected from the surrounding image obtained by photographing the surroundings of the host vehicle 1 with a camera. For example, on the captured image obtained by photographing with a camera, points (feature points) having features in the form of edges or corners of objects such as road markings, road boundaries, and obstacles, where the luminance of adjacent pixels changes by a predetermined amount or more, may be detected as objects. The controller 19 stores learned object data related to the learned objects in the storage device 19b. For example, the learned object data may include data representing the feature amounts of the learned objects (hereinafter referred to as "feature amount data") and data on the relative positional relationship between the target parking position 31 and the learned objects (hereinafter referred to as "relative position data"). As the relative position data, for example, the relative position of the learned object with respect to the target parking position 31 may be stored. For example, the controller 19 can obtain the position of the learned object detected when the host vehicle 1 is parked at the target parking position 31 as the relative position of the learned object with respect 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 a reference point (hereinafter referred to as "map coordinate system") may be stored.

[0015] Fig. 2(b) is an explanatory diagram of an example of the process during parking support implementation. When an operation by the user (hereinafter sometimes referred to as the "activation operation") that instructs the start of the parking support control of the host vehicle 1 is performed, the controller 19 starts the parking support control of the host vehicle 1. 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 target parking position 31 which is a registered parking position candidate. The controller 19 may be set to switch between an automatic start mode in which the parking support control is automatically started when the host vehicle 1 approaches the registered target parking position 31 and a manual start mode in which the parking support control is not automatically started even when the host vehicle 1 approaches the registered target parking position 31.

[0016] When the parking support control starts, the controller 19 extracts targets around the host vehicle 1 using the external sensor 15. In the following description, the targets around the host vehicle 1 extracted during parking support implementation are referred to as "surrounding targets". In Fig. 2(b), the triangular plots represent the surrounding targets. The controller 19 detects the target parking position 31 by matching the learned targets and the surrounding targets and associating the same feature points with each other. Based on the relative positional relationship between the surrounding targets detected during parking support implementation and the host vehicle 1, and the relative positional relationship between the learned targets associated with the surrounding targets and the target parking position 31, the relative position of the host vehicle 1 with respect to the target parking position 31 is calculated.

[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. 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.

[0018] Figure 3 is a schematic diagram illustrating the parking assistance control in the second assistance mode. In the second assistance mode as well, the controller 19 starts assisting with parking the vehicle 1 when the user performs an activation operation to instruct the activation of the parking assistance control. 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 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. Hereinafter, one of the available spaces 31a to 31d set as the target parking position may be referred to as "target parking position 31".

[0019] For example, the controller 19 may set the available parking space around its own vehicle 1 as the target parking position 31 based on the detection result of the parking space line 35 indicating the parking space. Alternatively, the controller 19 may detect parked vehicles as objects around its own vehicle 1 and set the space between parked vehicles as 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 calculated target parking path 34, the controller 19 performs parking assistance control for the vehicle.

[0020] The user can arbitrarily switch the control mode of the parking assist control between the first assist mode and the second assist mode by operating the mode selector switch 18. In the following description, the instruction to switch the control mode of the parking assist control by operating the mode selector switch 18 may be referred to as a "switching instruction". However, if the user attempts to switch control modes while the vehicle 1 is in motion, there is a risk that the user's attention to their surroundings may be neglected during the switching operation. Therefore, when the controller 19 has selected one of the first support modes or the second support mode, and receives a user instruction to switch to the other mode, if the vehicle 1 is stopped, it permits switching from one mode to the other. On the other hand, if the vehicle 1 is not stopped when the switching instruction is received, it does not permit switching from one mode to the other. When determining whether the vehicle 1 is stopped or not, for example, it may be determined whether the speed detected by the vehicle speed sensor is 0 km / h, and if the speed detected by the vehicle speed sensor is 0 km / h, it may be determined that the vehicle 1 is stopped. Alternatively, a margin may be set, and it may be determined that the vehicle 1 is stopped if the speed detected by the vehicle speed sensor is below a predetermined speed.

[0021] (operation) Figure 4 is a state transition diagram of an example of the operating state of the parking assist device 10 of the first embodiment. When the user performs a start operation to instruct the start of parking assist control, the controller 19 starts parking assist control, and the control mode of the parking assist control transitions to either the first assist mode (ST01) or the second assist mode (ST02). For example, if there is a registered parking position candidate near the current position of the vehicle 1, the system transitions to the first assist mode (ST01), and if there is a registered parking position candidate near the current position of the vehicle 1, the system transitions to the first assist mode (ST01). Parking location If no candidates exist, the system may transition to the second support mode (ST02). If the control mode is in the first support mode (ST01) and vehicle 1 is stopped, and a switching instruction is received, the control mode will transition to the second support mode (ST02) (C1). Also, if the control mode is in the second support mode (ST02) and vehicle 1 is stopped, and a switching instruction is received, the control mode will transition to the first support mode (ST01) (C2).

[0022] On the other hand, even if a switching instruction is received while the vehicle 1 is in motion and the control mode is in the first support mode (ST01), the control mode will not transition to the second support mode (ST02) (C3). Similarly, even if a switching instruction is received while the vehicle 1 is in motion and the control mode is in the second support mode (ST02), the control mode will not transition to the first support mode (ST01) (C4). By prohibiting mode switching while the vehicle 1 is in motion in this way, safety during support mode switching is improved in the parking support device 10 which has a first support mode and a second support mode.

[0023] (Second Embodiment) Figure 5 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.

[0024] 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.

[0025] The parking assistance control unit 51, when set to automatic start mode, determines whether the current position of the vehicle 1 is near a registered parking position candidate. Parking location If it is near the candidate Parking location The candidate is set as the target parking position 31 and parking assistance control is started, operating the parking assistance device 10 in first assistance mode. Meanwhile, if the parking assistance control unit 51 is set to manual start mode, when it receives a control start command from the HMI control unit 50, the current position of the vehicle 1 is registered Parking location Determine whether or not you are near a candidate. The current location of your vehicle 1 is registered Parking location If the location is near a candidate, the parking assistance control unit 51 Parking location The candidate is set as the target parking position 31 and the parking assist device 10 is operated in first assist mode. The current position of the vehicle 1 is registered Parking location If the parking location is not near a candidate spot, the parking assistance control unit 51 operates the parking assistance device 10 in second assistance mode. The parking support control unit 51 also outputs a parking position calculation command to the target parking position detection unit 57. In the case of parking support control in the first support mode, the target parking position detection unit 57 receives the target data output from the target detection unit 54 as target data of 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 the target parking position 31 by matching the learned targets with the surrounding targets and associating targets with the same feature points. 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 parking position detection unit 57 calculates the relative position of the vehicle 1 with respect to the target parking position 31.

[0026] In the second support mode of parking assistance control, the target parking position detection unit 57 detects available parking spaces around the vehicle 1 based on the detection results obtained by the external sensor 15, which detects white lines around the vehicle 1 and objects around the vehicle 1 (such as parked vehicles), and registers the detected available space as 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.

[0027] In the case of parking assistance control in the first assistance mode, the HMI control unit 50 displays the parking assistance screens illustrated in Figures 6(a) to 6(c) on the display device of the HMI 13. Figure 6(a) is a schematic diagram of an example of a parking assistance screen 70a displayed when the control mode is the first assistance mode and the vehicle 1 is stopped (hereinafter sometimes referred to as the "first state"). Figure 6(b) is a schematic diagram of an example of a parking assistance screen 70b displayed when the control mode is the first assistance mode and the vehicle 1 is traveling at a vehicle speed less than the threshold Vth (hereinafter sometimes referred to as the "second state"). Figure 6(c) is a schematic diagram of an example of a parking assistance screen 70c displayed when the control mode is the first assistance mode and the vehicle speed of the vehicle 1 is greater than or equal to the threshold Vth (hereinafter sometimes referred to as the "third state"). The threshold Vth may be, for example, 10 [km / h]. The parking assistance screens 70a to 70c include the display of the first switch button 18a and the second switch button 18b, which are GUIs for the mode switching switch 18. When the user operates the first switch button 18a and the second switch button 18b on the parking assistance screen, the touch panel provided as the mode switching switch 18 on the display device detects these operations. The first switch button 18a is a button that accepts a switching instruction to switch the control mode of the parking assistance control from the second assistance mode to the first assistance mode, and the second switch button 18b is a button that accepts a switching instruction to switch the control mode of the parking assistance control from the first assistance mode to the second assistance mode.

[0028] The second toggle button 18b on the parking assistance screen 70a is enabled. Therefore, in the first state, the HMI control unit 50 accepts operation of the second toggle button 18b by the user. Consequently, when the second toggle button 18b is operated in the first state, the parking assistance control unit 51 switches the control mode to the second assistance mode. On the other hand, the second toggle button 18b on the parking assistance screens 70b and 70c is disabled. Therefore, in the second and third states, the HMI control unit 50 does not accept operation of the second toggle button 18b. Consequently, even if the second toggle button 18b is operated while the vehicle 1 is in motion, the parking assistance control unit 51 does not switch the control mode.

[0029] Furthermore, the parking assistance screens 70a and 70b include an image 71 captured by the camera of the external sensor 15 and an overhead view image 72 generated by converting the camera's captured image, as surrounding images generated by capturing images of the area around the vehicle 1. On the other hand, the parking assistance screen 70c includes a CG image 73 that includes an icon 73a of the vehicle 1 as seen from the rear, instead of the captured image 71 and the overhead view image 72. In other words, in the first and second states, the HMI control unit 50 displays the captured image 71 and the overhead view image 72 on the display device, while in the third state, the captured image 71 and the overhead view image 72 are not displayed on the display device. Furthermore, the captured image 71 is superimposed with vehicle width boundary guide lines 71L and 71R, which represent the left and right boundaries of the vehicle width of the vehicle 1, respectively. In addition, the overhead view image 72 displays an icon 72a representing the current position of the vehicle 1 in the overhead view image 72, and vehicle width boundary guide lines 72L and 72R representing the left and right boundaries of the vehicle width of the vehicle 1, respectively, superimposed on it.

[0030] Furthermore, in the parking assistance screen 70a of the first state, a target parking position mark 72b representing the target parking position detected by the target parking position detection unit 57 and an adjustment switch 72c that accepts user input for fine-tuning the target parking position are superimposed on the overhead image 72. If the target parking position detection unit 57 detects multiple target parking positions located near the current position of the vehicle 1, the first switching button 18a is used as a switching button to select the target parking position for parking the vehicle 1 from among these multiple candidate target parking positions. In addition, in the example of the overhead image 72 of the first state in Figure 6(a), the scale is reduced compared to the overhead image 72 of the second state in Figure 6(b), so that the range of a predetermined size of the parking space of the target parking position is represented on the parking assistance screen 70a. In the example of Figure 6(a), the entire parking space is represented. The parking assistance screen 70a in the first state includes a parking start button 74 that instructs the user to start parking assistance. When the HMI control unit 50 receives the user's input of the parking start button 74, the parking assistance control unit 51 starts parking assistance to the target parking position. For example, it controls the vehicle 1 to drive along the target parking path to the target parking position.

[0031] In the second state's parking assistance screen 70b, the target parking position mark 72b is not displayed and the parking start button 74 is disabled. Therefore, in the second state, the parking assistance control unit 51 does not start parking assistance. Furthermore, the parking assistance screens 70a to 70c include a message display area 75 where notifications such as visual messages are displayed, and an end button 76 for instructing the stopping of parking assistance control. For example, in the first state parking assistance screen 70a, notifications such as visual messages indicating the success or failure of target parking position detection may be displayed in the message display area 75. Also, in the second state parking assistance screen 70b and the third state parking assistance screen 70c, notifications such as visual messages indicating that target parking position detection will begin when the vehicle 1 stops may be displayed in the message display area 75.

[0032] On the other hand, in the case of parking assistance control in the second assistance mode, the HMI control unit 50 displays the parking assistance screens illustrated in Figures 7(a) to 7(c) on the display device of the HMI 13. Figure 7(a) is a schematic diagram of an example of a parking assistance screen 70d that is displayed when the control mode is the second assistance mode and the vehicle 1 is stopped (hereinafter sometimes referred to as the "fourth state"). Figure 7(b) is a schematic diagram of an example of a parking assistance screen 70e that is displayed when the control mode is the second assistance mode and the vehicle 1 is traveling at a vehicle speed less than the threshold Vth (hereinafter sometimes referred to as the "fifth state"). Figure 7(c) is a schematic diagram of an example of a parking assistance screen 70f that is displayed when the control mode is the second assistance mode and the vehicle speed of the vehicle 1 is greater than or equal to the threshold Vth (hereinafter sometimes referred to as the "sixth state").

[0033] The first toggle button 18a on the parking assistance screen 70d is enabled. Therefore, in the fourth state, the HMI control unit 50 accepts operation of the first toggle button 18a by the user. 4When the first switch button 18a is operated in this state, the parking assistance control unit 51 switches the control mode to the first assistance mode. On the other hand, the first switch button 18a on the parking assistance screens 70e and 70f is disabled. Therefore, even if the first switch button 18a is operated while the vehicle 1 is in motion, the parking assistance control unit 51 does not switch the control mode to the first assistance mode. Parking assistance screens 70d and 70e include the camera image 71 and the overhead view image 72. On the other hand, parking assistance screen 70f includes a CG image 73 instead of the camera image 71 and the overhead view image 72. That is, in the fourth and fifth states, the HMI control unit 50 displays the camera image 71 and the overhead view image 72 on the display device, while in the sixth state, the camera image 71 and the overhead view image 72 are not displayed on the display device.

[0034] The captured image 71 displays the vehicle width boundary guide lines 71L and 71R superimposed on it. The overhead view images 72 of the parking assistance screens 70d and 70e display the icon 72a and the vehicle width boundary guide lines 72L and 72R superimposed on it. Furthermore, in the fourth-state parking assistance screen 70d and the fifth-state parking assistance screen 70e, target parking position marks 77a and 77b, representing empty spaces detected by the target parking position detection unit 57 as candidate target parking positions, a direction indicator mark 77c, indicating the direction in which the empty space was detected, and an adjustment switch 72c are superimposed on the overhead image 72. When selecting a target parking position for parking the vehicle 1 from multiple empty spaces, the user directly touches the target parking position marks 77a and 77b. The target parking position mark 77a for the currently selected empty space is displayed larger than the target parking position marks 77b for other empty spaces. Additionally, when making fine adjustments to the target parking position within the parking space, the user directly touches the adjustment switch 72c. Furthermore, the overhead view images 72 of the parking assistance screens 70d and 70e are superimposed with guide lines 78L and 78R indicating the search range for parking space lines. Each of the guide lines 78L and 78R represents the area between an adjacent pair of lines as the search range for parking space lines. Note that, as shown in Figures 6(a) and 6(b), the overhead view images 72 of the parking assistance screen 70a in the first state and the parking assistance screen 70b in the second state do not display the guide lines 78L and 78R. The CG image 73 of the parking assistance screen 70f in the sixth state displays frame line search range marks 79L and 79R, which schematically represent the search range for finding the target parking position.

[0035] Furthermore, the parking assistance screen 70d in the fourth state includes a parking start button 74. When the HMI control unit 50 receives a user's input using the parking start button 74, the parking assistance control unit 51 starts assisting with parking to the target parking position. On the other hand, in the parking assistance screen 70e in the fifth state, the target parking position mark 72b is not displayed and the parking start button 74 is disabled. Therefore, 5 In this state, the parking assistance control unit 51 will not start parking assistance. The parking assistance screens 70d to 70e include a message display area 75 and an exit button 76. For example, in the parking assistance screen 70d of the fourth state, a visual message or other notification indicating that the target parking position can be fine-tuned within the parking space by operating the adjustment switch 72c may be displayed in the message display area 75. In the parking assistance screen 70e of the fifth state, a visual message or other notification indicating that the target parking position has been detected may be displayed in the message display area 75 when the target parking position is detected. In the parking assistance screen 70f of the sixth state, a visual message or other notification indicating that parking assistance can be started when the vehicle 1 stops near the parking space may be displayed in the message display area 75. Furthermore, in the parking assistance screen 70e of the fifth state, a visual message or other notification indicating that parking assistance can be started when the vehicle 1 stops near a parking space may be displayed in the message display area 75. In the parking assistance screen 70f of the sixth state, a visual message or other notification indicating that the target parking position has been detected may be displayed in the message display area 75 when the target parking position is detected.

[0036] Figure 8 is a flowchart of an example of the operation at the start of parking assistance control. In step S1, the parking assistance control unit 51 determines whether the current position of the vehicle 1 is near a registered parking position candidate. If the current position is near a parking position candidate (step S1:Y), the control mode is set to the first assistance mode and the process proceeds to step S2. If the current position is not near a parking position candidate (step S1:N), the control mode is set to the second assistance mode and the process proceeds to step S7.

[0037] In step S2, the parking assistance control unit 51 determines whether the vehicle speed of the vehicle 1 is less than the threshold Vth. If the vehicle speed is less than the threshold Vth (step S2:Y), the process proceeds to step S3. If the vehicle speed is not less than the threshold Vth (step S2:N), the process proceeds to step S6. In step S3, the parking assistance control unit 51 determines whether the vehicle is stopped. If the vehicle 1 is stopped (step S3:Y), the process proceeds to step S4. If the vehicle is not stopped (step S3:N), the process proceeds to step S5.

[0038] In step S4, the parking assist device 10 enters the first state, switching to the second assist mode is permitted, and the parking assist screen 70a is displayed on the display device. In step S5, the parking assist device 10 enters the second state, switching to the second assist mode is prohibited, and the parking assist screen 70b is displayed on the display device. In step S6, the parking assist device 10 enters the third state, switching to the second assist mode is prohibited, and the parking assist screen 70c is displayed on the display device. On the other hand, in step S7, the parking assistance control unit 51 determines whether the vehicle speed of the vehicle 1 is less than the threshold Vth. If the vehicle speed is less than the threshold Vth (step S7:Y), the process proceeds to step S8. If the vehicle speed is not less than the threshold Vth (step S7:N), the process proceeds to step S11.

[0039] In step S8, the parking assistance control unit 51 determines whether the vehicle is stopped or not. If the vehicle 1 is stopped (step S8:Y), the process proceeds to step S9. If the vehicle 1 is not stopped (step S8:N), the process proceeds to step S10. In step S9, the parking assistance device 10 enters the fourth state, switching to the first assistance mode is permitted, and the parking assistance screen 70d is displayed on the display device. In step S10, the parking assistance device 10 enters the fifth state, switching to the first assistance mode is prohibited, and the parking assistance screen 70e is displayed on the display device. In step S11, the parking assistance device 10 enters the sixth state, switching to the first assistance mode is prohibited, and the parking assistance screen 70f is displayed on the display device.

[0040] Figure 9 The second This is a state transition diagram of an example of the operating state of the parking assist device 10 of the embodiment. When a switching instruction is received in the first state (ST1), the state of the parking assist device 10 transitions to the fourth state (ST4) (C11). That is, the control mode switches from the first assist mode to the second assist mode. In the first state, when the vehicle 1 is traveling at a speed less than the threshold Vth, the state of the parking assist device 10 transitions to the second state (ST2) (C12). In the second state, when the vehicle 1 stops, the state of the parking assist device 10 returns to the first state (C13), and when the vehicle speed becomes equal to or greater than the threshold Vth, the state of the parking assist device 10 transitions to the third state (ST3) (C14). In the third state, when the vehicle speed becomes less than the threshold Vth, the state of the parking assist device 10 returns to the second state (C15). In the second and third states, even if a switching instruction is received, the state does not transition (C16, C17). That is, the control mode does not switch from the first assist mode to the second assist mode.

[0041] In the fourth state (ST4), if at least one target parking position is registered in the storage device 19b and a switching instruction is received, the state of the parking assist device 10 transitions to the first state (ST1) (C21). That is, the control mode switches from the second assist mode to the first assist mode. If no target parking position is yet registered in the storage device 19b, the state does not transition even if a switching instruction is received (C22). That is, the control mode does not switch from the second assist mode to the first assist mode. In the fourth state, if the vehicle 1 is traveling at a speed less than the threshold Vth, the state of the parking assist device 10 transitions to the fifth state (ST5) (C23). In the fifth state, if the vehicle 1 stops, the state of the parking assist device 10 returns to the fourth state (C24), and if the vehicle speed becomes greater than or equal to the threshold Vth, the state of the parking assist device 10 transitions to the sixth state (ST6) (C25). In state 6, when the vehicle speed falls below the threshold Vth, the state of the parking assist device 10 returns to state 5 (C26). State 5 and 6 Even if a switching instruction is received in the state, the state does not change (C27, C28). In other words, the control mode does not switch from the second support mode to the first support mode.

[0042] (Effects of the embodiment) (1) When the controller 19 has selected one of the first support mode and the second support mode and receives a command to switch to the other mode, if the vehicle 1 is stopped, it permits switching from one mode to the other mode. However, if the vehicle 1 is not stopped when the command to switch is received, it does not permit switching from one mode to the other mode. This improves safety when switching between support modes in a parking assist system that has multiple different support modes.

[0043] (2) In the first support mode, the controller 19 may store data representing the relative positional relationship between the target parking position and the objects present around the target parking position in the memory device as learned object data, detect surrounding objects which are objects present around the vehicle 1, and detect pre-registered parking position candidates based on the learned object data and the surrounding objects. In the second support mode, the controller 19 may detect available parking spaces around the vehicle 1 based on the detection results obtained by the sensor from detecting white lines or objects around the vehicle 1, and set the detected available space as the target parking position. If the vehicle 1 is located near a pre-registered parking position candidate, the first support mode may be selected when starting the parking support control to assist in parking the vehicle 1 at the target parking position. This allows the control mode at the start of the parking support control to be appropriately selected depending on whether or not a target parking position has been registered.

[0044] (3) The controller 19 displays the surrounding image generated by imaging the area around the vehicle 1 on the display device when the vehicle speed of the vehicle 1 is below the threshold, and does not need to display the surrounding image on the display device when the vehicle speed of the vehicle 1 is above the threshold. This allows the appropriate screen display to be selected according to the vehicle speed. (4) When the second support mode is selected, the controller 19 displays guide lines indicating the search range for parking space lines on the surrounding image, but does not need to display guide lines on the surrounding image when the first support mode is selected. Also, when the second support mode is selected, the search range for searching for the target parking position is displayed on the display device, but does not need to display the search range on the display device when the first support mode is selected. This allows the screen display to be set according to the control mode of the parking assistance control.

[0045] (5) When the first support mode is selected and the vehicle 1 is traveling at a speed below a threshold, the controller 19 may display a notification on the display device informing the user that it will start detecting a target parking position when the vehicle 1 stops. When the second support mode is selected and the vehicle 1 is traveling at a speed below a threshold, the controller 19 may display a notification on the display device informing the user that an empty parking space has been detected. Furthermore, when the first support mode is selected and the vehicle 1 is moving, the controller 19 may display a notification on the display device informing the user that it will start setting or detecting a target parking position when the vehicle 1 stops. When the second support mode is selected and the vehicle 1 is moving, the controller 19 may display a notification on the display device informing the user that parking assistance can be started when the vehicle 1 stops. This allows the user to be presented with information corresponding to the combination of the control mode of the parking assistance control and the vehicle speed of the vehicle 1.

[0046] 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]

[0047] 1...Own vehicle, 10...Parking assist device, 11...Positioning device, 12...Map database, 13...Human-machine interface, 14...Shift switch, 15...External sensor, 16...Vehicle sensor, 17...Parking switch, 18...Mode switching 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, If the vehicle is stopped when a command to switch to the other mode is received while one of the following modes is selected—a first support mode that assists parking by setting a pre-registered parking position candidate to the target parking position—the system permits switching from the first mode to the other mode. If the vehicle is not stopped when the aforementioned switching instruction is received, switching from one mode to the other mode will not be permitted. A parking assistance method characterized by the following features.

2. The parking assistance method according to claim 1, characterized in that, in the first assistance mode, data representing the relative positional relationship between objects present around the target parking position and the target parking position is stored in a storage device as learned object data, surrounding objects which are objects present around the vehicle are detected, and the pre-registered parking position candidates are detected based on the learned object data and the surrounding objects.

3. The parking assistance method according to claim 1 or 2, characterized in that, in the second assistance mode, the system detects available parking spaces around the vehicle based on the detection results obtained by a sensor detecting white lines or objects around the vehicle, and sets the detected available space as the target parking position.

4. If the vehicle is located near one of the pre-registered parking position candidates, the first support mode is selected when activating the parking support control to assist in parking the vehicle at the target parking position. If the vehicle is not located near one of the pre-registered parking position candidates, the second assistance mode is selected when the parking assistance control is activated. The parking assistance method according to feature 1 or 2.

5. If the vehicle speed of the vehicle is below a threshold, the surrounding image generated by imaging the area around the vehicle is displayed on the display device; if the vehicle speed of the vehicle is equal to or greater than the threshold, the surrounding image is not displayed on the display device. The parking assistance method according to feature 1 or 2.

6. The parking assistance method according to claim 5, characterized in that when the second assistance mode is selected, guide lines indicating the search range for parking space lines are displayed on the surrounding image, and when the first assistance mode is selected, the guide lines are not displayed on the surrounding image.

7. If the first support mode is selected and the vehicle is traveling at a speed below a threshold, a notification is displayed on the display device indicating that when the vehicle stops, detection of the target parking position will begin. If the second support mode is selected and the vehicle is traveling at a speed below a threshold, an empty parking space is detected, a notification indicating that the empty parking space has been detected is displayed on the display device. The parking assistance method according to feature 1 or 2.

8. If the first support mode is selected and the vehicle is in motion, a notification will be displayed on the display device indicating that setting or detection of the target parking position will begin when the vehicle stops. If the second support mode is selected and the vehicle is in motion, a notification will be displayed on the display device indicating that parking assistance can be started when the vehicle comes to a stop. The parking assistance method according to feature 1 or 2.

9. The parking assistance method according to claim 1 or 2, characterized in that when the second assistance mode is selected, the search range for searching the target parking position is displayed on the display device, and when the first assistance mode is selected, the search range is not displayed on the display device.

10. A parking assist device that assists in parking the vehicle at a target parking position, A user interface that accepts instructions to switch between a first support mode, which assists parking by setting a pre-registered parking position candidate to the target parking position, and a second support mode, which assists parking by setting the target parking position without using a pre-registered parking position candidate, A controller that, when one of the first support mode and the second support mode is selected and a switching instruction to the other mode is received, permits switching from the first mode to the other mode if the vehicle is stopped, and does not permit switching from the first mode to the other mode if the vehicle is not stopped when the switching instruction is received. A parking assistance device characterized by being equipped with the following features.

Images