Parking assist system

Abstract

A parking assist system is provided. A parking assist system includes a vehicle control unit, a catch position estimation unit, and an error amount estimation unit. The vehicle control unit sets an assumed contact area (A) on the basis of the estimated catch position (Pc) estimated by the catch position estimation unit, and performs pre-stop control for causing the vehicle to travel at a contact preparation speed within the assumed contact area (A). As the estimated error amount estimated by the error amount estimation unit becomes smaller, the vehicle control unit reduces the expected contact area (A).

Description

Technical Field

[0001] The present invention relates to a parking assist system that performs vehicle control for moving the vehicle to a parking space. Background Art

[0002] Japanese Patent Application Laid-Open No. 2022-72962 (Patent Document 1) discloses a parking assistance system that controls the driving and braking forces acting on the wheels to move the vehicle into a parking space. The parking assistance system of Patent Document 1 sets a movement path for the vehicle to move into the parking space, gradually reduces the vehicle's speed based on the remaining distance to the target position, and stops the vehicle when the vehicle reaches the target position or when the wheels contact the wheel chocks.

[0003] In the parking assist system of Patent Document 1, the vehicle reduces its speed from the moment it begins to enter the parking space, and thereafter reduces its speed further from the moment the steering angle becomes 0. This prevents the vehicle from reaching the wheel stoppers with a strong momentum.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-72962

[0005] However, depending on the parking situation, the steering angle may reach zero very early. In this case, if the vehicle speed drops significantly from the moment the steering angle reaches zero, the distance and time required to travel at the extremely low speed will increase, potentially reducing convenience. Summary of the Invention

[0006] Therefore, it is desired to realize a parking assist system that ensures convenience and enables a vehicle to be properly moved to a parking space.

[0007] A parking assistance system according to the present disclosure includes a vehicle control unit that controls driving force and braking force acting on wheels to perform vehicle control for moving a vehicle having the wheels into a parking space. The parking assistance system further includes: a wheel stopper position estimating unit that estimates a position of a wheel stopper in the parking space; and an error amount estimating unit that estimates an error amount of a position recognition system of the vehicle. The vehicle control unit sets, on the vehicle side of the estimated wheel stopper position, an assumed contact area, an area where there is a possibility of contact between the wheel and the wheel stopper. The vehicle performs pre-stop control within the assumed contact area for causing the vehicle to travel at a preset contact preparation speed. The vehicle control unit reduces the assumed contact area as the estimated error amount estimated by the error amount estimating unit decreases.

[0008] This configuration allows the vehicle to travel at the contact preparation speed by executing pre-stop control within a hypothetical contact area set based on the estimated wheel stopper position, thereby easily preventing the vehicle from reaching the wheel stopper with strong momentum. By reducing the estimated error in the vehicle's position recognition system, the hypothetical contact area is reduced, preventing the vehicle from unnecessarily increasing the distance traveled at low speeds. This provides a parking assistance system that ensures convenience and enables the vehicle to be properly moved into a parking space.

[0009] Further features and advantages of the technology to which the present disclosure relates will become more apparent from the following description of illustrative and non-limiting embodiments described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is an explanatory diagram showing an example of parking assistance.

[0011] Figure 2 This is a schematic block diagram showing an example of a system configuration of a vehicle including a parking assist system.

[0012] Figure 3 It is the functional block diagram of the parking assist system.

[0013] Figure 4 This is a schematic diagram showing a method for setting the contact assumption area.

[0014] Figure 5 This is a coordinate diagram showing changes in vehicle speed corresponding to the position of the vehicle during parking assistance.

[0015] Figure 6 This is a coordinate diagram showing changes in driving force corresponding to the position of the vehicle during parking assistance.

[0016] Figure 7 Schematic diagram showing an example of setting the size of the assumed contact area.

[0017] Figure 8 Schematic diagram showing an example of setting the size of the assumed contact area.

[0018] Figure 9 Schematic diagram showing an example of setting the size of the assumed contact area.

[0019] Figure 10 Schematic diagram showing an example of setting the size of the assumed contact area.

[0020] Figure 11 A schematic diagram showing an example of setting the size of the assumed contact area. DETAILED DESCRIPTION

[0021] Embodiments of the parking assist system will be described with reference to the accompanying drawings. Figure 1 The explanatory diagram of FIG shows a method of parking assistance when parking the vehicle 50. Figure 2 The block diagram schematically shows an example of a system configuration of a vehicle 50 including a parking assist system 100. The parking assist system 100 of this embodiment controls the driving force and braking force acting on the wheels W and controls the steering angle to perform vehicle control for moving the vehicle 50 into a parking space E.

[0022] In this embodiment, the parking assist system 100 parks the vehicle 50 in the parking space E through automatic driving. Alternatively, semi-automatic driving may be employed in which the driver manually steers based on guidance from the parking assist system 100 and only automatic driving is used for driving and braking.

[0023] like Figure 2 As shown, parking assistance system 100 is implemented around an ECU (electronic control unit) 1, which coordinates with other systems and various sensors. ECU 1 comprises a processor 1P, such as a microcomputer, microprocessor, or DSP (digital signal processor), a program memory 1M storing software such as programs and parameters, and various other electronic components.

[0024] Processor 1P is the core hardware of ECU 1, and implements the vehicle control unit through cooperation with various hardware components centered on processor 1P and software such as programs stored in program memory 1M. Furthermore, with ECU 1 as the core, parking assistance system 100 is implemented through cooperation with ECU 1, other systems such as drive system 20, brake system 30, steering system 40, and position recognition system 60, as well as various sensors and peripheral devices indicated by reference numerals 51 through 58 and 61.

[0025] In the following description, various functional units constituting the parking assist system 100 are described. However, each functional unit may be implemented by multiple hardware components or by cooperation between at least one hardware component and software, and does not necessarily need to be configured as an independent component.

[0026] like Figure 1As shown, the parking assistance system 100 moves the vehicle 50 to the parking target position Pt set in the parking space E and stops the vehicle 50 there. The parking target position Pt and the current position Pr correspond to coordinates in the coordinate system (parking assistance coordinate system) used when the parking assistance system 100 performs parking assistance (vehicle control).

[0027] Figure 1 The reference symbol "Q" shown in the figure represents a reference point on vehicle 50 used to determine the position of vehicle 50. Furthermore, in the parking assistance coordinate system, the current position Pr corresponds to the coordinates of reference point Q. The target parking position Pt represents the coordinates of reference point Q on vehicle 50 when vehicle 50 is properly positioned in parking space E. Based on the current position Pr and the target parking position Pt, the parking assistance system 100 calculates the movement trajectory of reference point Q as vehicle 50 moves from current position Pr to target parking position Pt, and defines this trajectory as a movement path K.

[0028] The parking assistance system 100 controls the vehicle so that a reference point Q moves from the current position Pr along a movement path K. When the reference point Q reaches the target parking position Pt, or in other words, when the current position Pr coincides with the target parking position Pt, the vehicle 50 is properly positioned within the parking space E, and the parking assistance system 100 stops the vehicle 50. Alternatively, the target parking position Pt may be the estimated wheel stopper position Pc (described later), and the reference point Q may be the position of the rear wheel axis.

[0029] Figure 1 This example illustrates so-called garage parking. For example, after the driver has passed parking space E, he or she stops vehicle 50 by turning the steering wheel slightly in the direction opposite to parking space E. This position can be referred to as the reverse start position, where vehicle 50 begins to reverse toward parking space E. While the steering wheel required for movement toward target parking position Pt increases, it is also possible to park vehicle 50 while traveling straight ahead, rather than turning the steering wheel in this manner. Furthermore, before starting movement from the stop position toward target parking position Pt, the direction of the steering wheel can be changed using so-called spot steering in coordination with the steering system 40.

[0030] Furthermore, it goes without saying that the parking assistance system 100 of this embodiment is not limited to garage parking, and can also be applied to so-called parallel parking (parallel parking).

[0031] When the driver moves vehicle 50 forward, the parking assist system 100 preferably provides guidance regarding the direction of travel and the stopping position (reverse start position). For example, the driver is preferably guided by a display on a monitor inside the vehicle cabin or by voice guidance, and the driver operates an accelerator pedal, brake pedal, steering wheel, etc. (all not shown) to move vehicle 50 to the reverse start position.

[0032] Alternatively, when vehicle 50 reaches the reverse start position, parking assistance system 100 notifies the driver that automated driving, including automatic steering, is possible. When the driver instructs the start of vehicle control by touching a start button, such as on a touch panel on a display inside the vehicle, operating operations of vehicle 50, including steering, are delegated to parking assistance system 100. Parking assistance system 100 then automatically moves vehicle 50 to target parking position Pt.

[0033] like Figure 2 As shown, the vehicle 50 includes, in addition to the ECU 1, which is the core of the parking assist system 100, a drive system 20, a brake system 30, a steering system 40, and a position recognition system 60. The drive system 20 is a system that controls the drive device 25 that drives the wheels W. The drive device 25 includes, for example, an internal combustion engine, a rotating electric machine, a gear mechanism, and an engagement device that connects / disconnects power transmission between rotating components, all of which are not shown. The brake system 30 is a system that generates braking force on the wheels W. The steering system 40 is a system that changes the direction of travel of the vehicle 50 by moving the steering wheel of the wheels W. The position recognition system 60 is a system that recognizes the position of the vehicle 50 (current position Pr).

[0034] Vehicle 50 also includes various sensors and peripheral devices, such as an accelerator sensor 51, a gear position sensor 52, a brake sensor 53, a speed sensor 54, an acceleration sensor 55, a steering angle sensor 56, a sonar 57, a camera 58, and a GNSS (Global Navigation Satellite System) receiver 61. For example, a GPS (Global Positioning System) receiver is used as GNSS receiver 61.

[0035] The throttle sensor 51 is a sensor that detects the amount of operation of the accelerator pedal by the driver. The gear sensor 52 is a sensor that detects the indication input of the operation mode of the drive device 25, such as the gear (including reverse, parking, etc.) indicated by the gear lever (not shown). The brake sensor 53 is a sensor that detects the amount of operation of the brake pedal by the driver. The speed sensor 54 is a sensor that detects the driving speed of the vehicle 50, that is, the rotation speed of the wheel W. The acceleration sensor 55 is a sensor that detects the acceleration of the vehicle 50. The acceleration sensor 55 of this embodiment can also detect, for example, the inclination angle and inclination direction of the ground on which the vehicle 50 is located. The steering angle sensor 56 is a sensor that detects the amount of operation of the steering wheel by the driver. Preferably, the operation amount is detected as the steering angle of the vehicle 50.

[0036] Sonar 57 is installed at various locations on vehicle 50 to detect the presence of obstacles around vehicle 50. Sonar 57 is preferably an active sonar. Furthermore, the obstacle sensor is not limited to sonar 57; a laser radar or other similar device may also be provided. Cameras 58 are installed at various locations on vehicle 50 to capture images of the surrounding area of ​​vehicle 50. A GNSS receiver 61 receives signals from GNSS satellites.

[0037] The sensors and peripheral devices indicated by reference numerals “51” to “58” and “61”, including the aforementioned ECU 1 (parking assist system 100 ), the drive system 20 , the braking system 30 , the steering system 40 , and the position recognition system 60 , are connected in a manner such that they can communicate with each other via an in-vehicle network 90 such as a CAN (controller area network).

[0038] For example, the drive system 20 cooperates with the accelerator sensor 51, the gear position sensor 52, the brake sensor 53, the speed sensor 54, the acceleration sensor 55, the steering angle sensor 56, and the like via the in-vehicle network 90 to control the drive device 25. The brake system 30 cooperates with the brake sensor 53 via the in-vehicle network 90 to control the brake mechanism 35. The steering system 40 cooperates with the steering angle sensor 56 to control the steering mechanism 45, including the steering wheel and steering control wheel. The position recognition system 60 recognizes the position of the vehicle 50 (current position Pr) based on the GNSS signal received by the GNSS receiver 61.

[0039] In the present embodiment, the position recognition system 60 recognizes the position of the vehicle 50 (current position Pr) based on information obtained from the speed sensor 54 , the steering angle sensor 56 , the camera 58 , and the like in addition to the GNSS signal.

[0040] like Figure 3As shown, parking assistance system 100 (ECU 1) includes a wheel stopper position estimation unit 11, an error estimation unit 12, an image recognition unit 13, a travel distance calculation unit 14, an object determination unit 15, and a vehicle control unit 16. Within each of these functional units, the calculation unit for performing various processes on input data is implemented using hardware, software (programs), or both. Figure 3 The illustrated approach is an illustrative and conceptual block diagram and does not limit the actual physical structure of the ECU 1 .

[0041] The wheel chock position estimating unit 11 estimates the position of the wheel chock in the parking space E. The error amount estimating unit 12 estimates the error amount of the position recognition system 60 of the vehicle 50. The image recognition unit 13 performs image recognition of an image captured by capturing the periphery of the vehicle 50. The travel distance calculating unit 14 calculates the travel distance of the vehicle 50. The object determining unit 15 determines the positional relationship between the recognition object R and the vehicle 50 based on the image recognition results obtained by the image recognition unit 13. The vehicle control unit 16 controls the driving force and braking force acting on the wheels W to control the vehicle 50 having the wheels W so as to move toward the parking space E.

[0042] The wheel stopper position estimating unit 11 estimates the position of the wheel stopper in the parking space E. The wheel stopper position estimating unit 11 estimates the position of the wheel stopper that is assumed to be provided in the parking space E where the vehicle 50 is to be parked by parking assistance. In this embodiment, the wheel stopper position estimating unit 11 does not directly identify the wheel stopper to determine its position, but rather estimates the position of the wheel stopper based on, for example, other objects that exist near the parking space E. Here, as an example of other objects that exist near the parking space E, Figure 4 The parking space E is divided into fixed objects such as parking space lines L. Regardless of whether the parking space E actually has a wheel stopper, the wheel stopper position estimating unit 11 estimates the position of the wheel stopper as if the wheel stopper exists.

[0043] The wheel stopper position estimating unit 11 uses the position of the top end Lf of the parking space line L identified by the image recognition unit 13 as a reference and estimates the position of the wheel stopper at a position set back from the top end Lf by a reference set distance Ds. In the present embodiment, the wheel stopper position estimated by the wheel stopper position estimating unit 11 is referred to as the "estimated wheel stopper position Pc." The reference set distance Ds can be set, for example, to the sum of the average wheelbase and the average front overhang of a typical vehicle 50.

[0044] Alternatively, another vehicle 50 existing in the adjacent parking space E, that is, a mobile body such as the adjacent vehicle C (see Figure 7) as another object existing near the parking space E. In this case, the wheel stopper position estimating unit 11 determines the estimated wheel stopper position Pc, for example, based on the position of the front end of the adjacent vehicle C recognized by the image recognition unit 13. The wheel stopper position estimating unit 11 determines the position of the adjacent vehicle C that is retracted rearward by a reference set distance Ds from the front end of the adjacent vehicle C as the estimated wheel stopper position Pc.

[0045] Reference Figures 4 to 6 The basic operation of the vehicle control unit 16 involved in the parking assistance of this embodiment will be described. Figure 4 As shown, the vehicle control unit 16 sets, based on the estimated wheel stopper position Pc determined by the wheel stopper position estimating unit 11, an assumed contact area A, which represents an area where the wheel W may come into contact with the wheel stopper, on the vehicle 50 side (front side) of the estimated wheel stopper position Pc. In the present embodiment, the vehicle control unit 16 sets the assumed contact area A as the area between the estimated wheel stopper position Pc and a position that is a predetermined assumed contact distance Dc forward from the estimated wheel stopper position Pc.

[0046] In this way, the vehicle control unit 16 performs the following calculation processing: based on the recognition object R (parking space line L, adjacent vehicle C, etc.) recognized by the image recognition unit 13 and the predetermined positional relationship between the recognition object R and the wheel stopper (the positional relationship determined by the reference set distance Ds and the contact assumption distance Dc with the position of the top end as a reference), the size of the contact assumption area A is calculated.

[0047] like Figure 5 As shown, the vehicle control unit 16 causes the vehicle 50 to travel at a preset assist speed limit V1 during parking assist. Figure 5 In the figure, the horizontal axis represents the position of the vehicle 50, and the origin corresponds to the starting position of parking assistance. The speed limit V1 during assistance is set to a speed that allows the vehicle 50 to move safely within the parking space E. The speed limit V1 during assistance can be set to, for example, approximately 1 km / h to 4 km / h.

[0048] If the vehicle 50, while performing parking assistance, enters the assumed contact area A, the vehicle control unit 16 executes pre-stop control. The vehicle 50's entry into the assumed contact area A can be determined based on whether the distance between the vehicle's reference point Q (e.g., the position of the rear wheel axis) and the estimated wheel stopper position Pc, obtained from the position recognition system 60, is less than or equal to the assumed contact distance Dc. Pre-stop control is performed to prepare for parking before the wheels W of the vehicle 50 contact the wheel stoppers. During pre-stop control, the vehicle control unit 16 causes the vehicle 50 to travel at a contact preparation speed V2, which is preset to a value lower than the assistance speed limit V1. The contact preparation speed V2 is set to a speed at which the impact of the wheels W contacting the wheel stoppers does not cause discomfort to the occupants. For example, the contact preparation speed V2 can be set to approximately 0 km / h to 1 km / h.

[0049] In addition, if Figure 6 As shown, the vehicle control unit 16 controls the drive system 20 so as to drive the vehicle 50 with a predetermined assist limited drive force T1 during the execution of parking assist. Figure 6 In, with Figure 5 Similarly, the horizontal axis represents the position of the vehicle 50, and the origin corresponds to the parking assist start position. The assist-period limited driving force T1 is set to a driving force that enables the vehicle 50 to properly move into the parking space E and prevents the wheels W from overrunning the wheel stoppers when they contact the wheel stoppers.

[0050] The vehicle control unit 16 controls the drive system 20 to drive the vehicle 50 with a contact preparation driving force T2 that is preset to a value lower than the assist-mode limit driving force T1 during pre-stop control executed when the vehicle 50 enters the assumed contact area A. The contact preparation driving force T2 is set to a driving force that enables the vehicle to stop without shock when the wheels W contact the wheel stoppers.

[0051] The parking assist system 100 (ECU 1) of this embodiment is characterized in that the size of the contact assumption area A can be variably set according to the situation. Figures 7 to 10 This point will be explained.

[0052] As described above, the assumed contact area A is set based on the estimated stopper position Pc determined by the stopper position estimating unit 11. This estimated stopper position Pc is determined based on the recognition target object R (parking space line L, adjacent vehicle C, etc.) recognized by the image recognition unit 13. It is estimated that the estimated stopper position Pc, which serves as the basis for setting the assumed contact area A, differs in accuracy when determined based on a fixed object such as the parking space line L and when determined based on a mobile object such as the adjacent vehicle C. It is estimated that a more accurate estimated stopper position Pc is obtained when the estimated stopper position Pc is determined based on a fixed object such as the parking space line L than when the estimated stopper position Pc is determined based on a mobile object such as the adjacent vehicle C.

[0053] Therefore, in this embodiment, when the recognized recognition target object R is a fixed object such as a parking space line L, the vehicle control unit 16 makes the contact assumption area A smaller than when the recognized recognition target object R is a moving object such as an adjacent vehicle C. Figure 7 An example of the contact assumption area A set when the recognized recognition target object R is the adjacent vehicle C is shown. In this figure, the contact assumption area A is set as the area between the estimated stopper position Pc and the position that is a first distance D1 forward from the estimated stopper position Pc. Figure 8 An example of the contact assumed area A set when the recognized recognition object R is the parking space line L is shown. In this figure, the contact assumed area A is set as the area between the estimated stopper position Pc and a position that is forward of the estimated stopper position Pc by a second distance D2 that is shorter than the first distance D1.

[0054] Furthermore, the information about the vehicle 50's position (current position Pr) acquired by the position recognition system 60 is not necessarily accurate but contains a certain amount of error. Furthermore, the amount of this error is not uniform across all vehicles 50 but may vary depending on the manufacturer, model, and grade. Naturally, the smaller the error, the more accurate the information about the vehicle 50's position (current position Pr).

[0055] Therefore, in this embodiment, the error amount estimating unit 12 estimates the error amount of the vehicle 50's position recognition system 60. As the error amount estimated by the error amount estimating unit 12, i.e., the estimated error amount, decreases, the vehicle control unit 16 reduces the size of the expected contact area A. As described above, in this embodiment, information on the vehicle 50's position (current position Pr) is obtained based on GNSS signals and information obtained from the speed sensor 54, the steering angle sensor 56, and the camera 58. While the errors in these GNSS signals are generally uniform across all vehicles 50, provided the GNSS type is the same, the information obtained from the speed sensor 54, the steering angle sensor 56, and the camera 58, and the determination results based thereon, may vary for each vehicle 50.

[0056] For example, the image recognition unit 13 performs image recognition on images captured by the camera 58 around the vehicle 50. However, this image recognition itself may contain errors. Furthermore, the travel distance calculation unit 14 calculates the travel distance of the vehicle 50 during parking assistance based on information obtained from the speed sensor 54. However, since the speed sensor 54 may contain detection errors, the calculated travel distance may also contain errors. Furthermore, the object determination unit 15 determines the positional relationship between the recognition object R and the vehicle 50 based on the image recognition results obtained by the image recognition unit 13. However, since image recognition may contain errors as described above, the determination result regarding the positional relationship between the recognition object R and the vehicle 50 may also contain errors. Taking these circumstances into account, the error amount estimation unit 12 of this embodiment calculates an estimated error amount by integrating the errors of the image recognition unit 13, the travel distance calculation unit 14, and the object determination unit 15.

[0057] The vehicle control unit 16 refers to the setting of the contact assumption area A. Figure 4 Based on the results of the aforementioned computational processing (the region from the estimated stopper position Pc to the region offset forward by the assumed contact distance Dc relative to the estimated stopper position Pc), the size of the assumed contact area A is adjusted to take into account the estimated error amount. Adjustment of the size of the assumed contact area A based on the estimated error amount may be performed in stages, for each of the divided stages, after dividing the estimated error amount into multiple stages, or may be performed linearly based on a predetermined relationship. In either case, as the estimated error amount calculated by the error amount estimating unit 12 decreases, the vehicle control unit 16 reduces the size of the assumed contact area A.

[0058] Figure 9An example of the contact assumption area A after adjustment is shown when the estimated error amount calculated by the error amount estimating unit 12 is relatively small when the recognized recognition target object R is the parking space line L. In this figure, the contact assumption area A is set to the area between the estimated stopper position Pc and the position that has advanced forward from the estimated stopper position Pc by a third distance D3 that is shorter than the second distance D2. On the other hand, Figure 10 An example of the adjusted assumed contact area A is shown when the estimated error amount calculated by the error amount estimating unit 12 is relatively large when the recognized recognition target object R is the parking space line L. In this figure, the assumed contact area A is set to the area between the estimated stopper position Pc and a position that is forward of the estimated stopper position Pc by a fourth distance D4 that is longer than the second distance D2.

[0059] in addition, Figure 9 as well as Figure 10 While the example in which the recognized object R is the parking space line L is shown, the same applies when the recognized object R is the adjacent vehicle C. As the estimated error decreases, the vehicle control unit 16 reduces the size of the expected contact area A. In this case, if the estimated error is relatively small, the expected contact area A is set to the area between the estimated stopper position Pc and a position that is a fifth distance forward from the estimated stopper position Pc, which is shorter than the first distance D1. On the other hand, if the estimated error is relatively large, the expected contact area A is set to the area between the estimated stopper position Pc and a sixth distance forward from the estimated stopper position Pc, which is longer than the first distance D1.

[0060] As described above, the parking assistance system 100 of this embodiment includes a vehicle control unit 16 that controls the driving force and braking force acting on the wheels W to control the vehicle 50 having the wheels W to move to the parking space E. The parking assistance system 100 further includes: a wheel stopper position estimating unit 11 that estimates the position of the wheel stopper in the parking space E; and an error amount estimating unit 12 that estimates the error amount of the position recognition system 60 of the vehicle 50. The control unit 16 sets a contact assumption area A, which is an area where there is a possibility of contact between the wheel W and the wheel chock, on the side of the vehicle 50 with respect to the estimated wheel chock position Pc, based on the position of the wheel chock estimated by the wheel chock position estimating unit 11. The control unit 16 executes pre-stop control for causing the vehicle 50 to travel at a preset contact preparation speed V2 within the contact assumption area A. As the error amount estimated by the error amount estimating unit 12, i.e., the estimated error amount, decreases, the vehicle control unit 16 reduces the contact assumption area A.

[0061] This configuration allows the vehicle 50 to travel at the contact preparation speed V2 within the assumed contact area A, which is set based on the estimated wheel stopper position Pc, to avoid the vehicle 50 reaching the wheel stopper with strong momentum. By reducing the assumed contact area A as the estimation error of the vehicle 50's position recognition system 60 decreases, the vehicle 50 can avoid unnecessarily increasing the distance traveled at a low speed. Consequently, a parking assistance system 100 can be provided that ensures convenience while enabling the vehicle 50 to be properly moved to the parking space E.

[0062] As one embodiment, it is preferable to further include an image recognition unit 13 that performs image recognition of an image acquired by photographing the periphery of the vehicle 50, and a vehicle control unit 16 that performs the following calculation processing: based on the recognition object R recognized by the image recognition unit 13 and a predetermined positional relationship between the recognition object R and the wheel chock, the size of an area where there is a possibility of contact with the wheel chock is calculated, and the vehicle control unit 16 sets the size of the contact assumption area A based on the result of the calculation processing and the size obtained by adding the estimated error amount.

[0063] According to this configuration, the size of the assumed contact region A can be appropriately set based on the result of the calculation process related to the size of the region where there is a possibility of contact with the wheel stoppers and the estimated error amount.

[0064] As one embodiment, the apparatus preferably includes: an image recognition unit 13 that performs image recognition of an image acquired by photographing the periphery of the vehicle 50; a travel distance calculation unit 14 that calculates the travel distance of the vehicle 50; and an object determination unit 15 that determines the positional relationship between the recognition object R and the vehicle 50 based on the image recognition result obtained by the image recognition unit 13, and an error amount estimation unit 12 that accumulates the errors of each of the image recognition unit 13, the travel distance calculation unit 14, and the object determination unit 15 to calculate the estimated error amount.

[0065] This configuration allows for highly accurate calculation of the estimated error amount, taking into account errors in the recognition system associated with image recognition and travel distance calculation, and errors in the determination system associated with determining the positional relationship between the recognition target object R and the vehicle 50. Consequently, the size of the assumed contact area A can be appropriately set.

[0066] As one embodiment, it is preferable that, within the contact assumed region A, the vehicle control unit 16 limits the driving force acting on the wheel W to a predetermined contact preparation driving force T2 or less.

[0067] According to this structure, when the wheel W contacts the wheel chock, it is easy to stop without going over the wheel chock.

[0068] [Other Implementation Methods]

[0069] (1) In the above embodiment, the wheel stopper position estimating unit 11 estimates the position of the wheel stopper based on other objects located near the parking space E. However, the present invention is not limited to this configuration. For example, the wheel stopper position estimating unit 11 may detect the wheel stopper itself using a laser radar or the like and then estimate the position of the wheel stopper as an estimated position including an error.

[0070] (2) In the above embodiment, the configuration in which the assumed contact area A is set as a two-dimensional area having a predetermined length in the path direction and a predetermined length in the width direction is primarily assumed and described. However, the configuration is not limited to this; the assumed contact area A may also be a one-dimensional area having a predetermined length in the path direction.

[0071] (3) In the above embodiment, the recognition target object R serving as a reference for determining the estimated wheel stopper position Pc is the parking space line L or the adjacent vehicle C. However, the present invention is not limited to this configuration. Any other object, such as a wall, a railing, or a coin parking barrier, may be used as the recognition target object R, as long as it is assumed to be present near the wheel stopper in the parking space E and can be recognized by the image recognition unit 13.

[0072] (4) In the above-mentioned embodiment, the vehicle control unit 16 adjusts the size of the contact assumption area A according to whether the identification target object R is a fixed object or a mobile object and the estimated error amount calculated by the error amount estimating unit 12 as an example. However, the present invention is not limited to such a structure, and the vehicle control unit 16 may adjust the size of the contact assumption area A only according to the estimated error amount calculated by the error amount estimating unit 12. In addition, the vehicle control unit 16 may adjust the size of the contact assumption area A based on other criteria on the premise of adjusting the size of the contact assumption area A according to the estimated error amount. For example, Figure 11 As shown, when the parking space E where the vehicle 50 is to be parked is a registered parking space Er registered in the parking assistance system 100 such as the garage of the home H, the assumed contact area A may be adjusted to be smaller.

[0073] (5) In the above embodiment, the vehicle control unit 16 reduces the expected contact area A when the estimated error amount calculated by the error amount estimating unit 12 is relatively small, and increases the expected contact area A when the estimated error amount is relatively large. However, the present invention is not limited to this configuration, and the vehicle control unit 16 may reduce the expected contact area A only when the estimated error amount calculated by the error amount estimating unit 12 is relatively small.

[0074] (6) In the above-described embodiment, the vehicle control unit 16 limits the vehicle speed to the contact preparation speed V2 and the driving force to the contact preparation driving force T2 during the pre-stop control executed when the vehicle 50 enters the contact assumed area A. However, the present invention is not limited to this configuration. During the pre-stop control, the vehicle control unit 16 only needs to limit the vehicle speed to at least the contact preparation speed V2, and the driving force limitation is not essential. Furthermore, the vehicle speed control and the driving force control during the pre-stop control may be performed either through feedforward control or through feedback control.

[0075] (7) In the above-described embodiment, the vehicle control unit 16 is primarily configured to decelerate the vehicle 50 in advance so that the vehicle speed is equal to or lower than the contact preparation speed V2 when the vehicle 50 reaches the expected contact area A. However, the present invention is not limited to this configuration, and the vehicle control unit 16 may also decelerate the vehicle 50 from the moment the vehicle 50 enters the expected contact area A. The same considerations can be applied to driving force limitation.

[0076] (8) The structures disclosed in each of the above-mentioned embodiments (including the above-mentioned embodiments and other embodiments; the same shall apply hereinafter) may be combined with the structures disclosed in other embodiments, as long as no contradiction arises. Regarding other structures, the embodiments disclosed in this specification are illustrative in all respects and may be appropriately modified without departing from the scope of the present disclosure.

[0077] [Summary of Implementation Methods]

[0078] In summary, the parking assistance system according to the present disclosure preferably includes the following structures.

[0079] A parking assistance system (100) includes a vehicle control unit (16) that controls the driving force and braking force acting on the wheels (W) to control the vehicle (50) having the wheels (W) to move toward a parking space (E). The parking assistance system (100) further includes: a wheel stopper position estimation unit (11) that estimates the position of the wheel stopper in the parking space (E); and an error amount estimation unit (12) that estimates the error amount of the position recognition system (60) of the vehicle (50). The vehicle control unit (16) estimates the error amount of the position recognition system (60) of the vehicle (50) based on the position of the wheel stopper. The position of the wheel stopper, i.e., the estimated wheel stopper position (Pc), estimated by the wheel stopper position estimating unit (11) is set as an area where there is a possibility of contact between the wheel (W) and the wheel stopper, i.e., a contact assumption area (A), on the side of the vehicle (50) closer to the estimated wheel stopper position (Pc). Within the contact assumption area (A), a pre-stop control is performed to cause the vehicle (50) to travel at a predetermined contact preparation speed (V2). As the error amount, i.e., the estimated error amount, estimated by the error amount estimating unit (12) becomes smaller, the vehicle control unit (16) reduces the contact assumption area (A).

[0080] According to this structure, by executing pre-stop control within a contact assumption area (A) set based on an estimated stopper position (Pc), the vehicle (50) is caused to travel at a contact preparation speed (V2), thereby easily avoiding a situation where the vehicle (50) reaches the stopper with a strong momentum. At this time, by reducing the estimated error amount of the position recognition system (60) of the vehicle (50), the contact assumption area (A) is reduced, thereby avoiding a situation where the distance traveled by the vehicle (50) at a low speed is unnecessarily increased. Therefore, a parking assistance system (100) can be provided that can ensure convenience and enable the vehicle (50) to be properly moved to a parking space (E).

[0081] As one embodiment, the vehicle control unit (16) is further provided with an image recognition unit (13), wherein the image recognition unit (13) performs image recognition of an image acquired by photographing the periphery of the vehicle (50), and the vehicle control unit (16) performs the following calculation processing: based on the recognition object (R) recognized by the image recognition unit (13) and a predetermined positional relationship between the recognition object (R) and the wheel stopper, the size of the area where there is a possibility of contact with the wheel stopper is calculated, and the vehicle control unit (16) sets the size of the contact assumption area (A) based on the result of the calculation processing and the size obtained by adding the estimated error amount.

[0082] According to this configuration, the size of the assumed contact area (A) can be appropriately set based on the result of the calculation process related to the size of the area where there is a possibility of contact with the wheel stoppers and the estimated error amount.

[0083] As one embodiment, the present invention preferably comprises: an image recognition unit (13) for performing image recognition of an image obtained by photographing the periphery of the vehicle (50); a travel distance calculation unit (14) for calculating the travel distance of the vehicle (50); and an object determination unit (15) for determining the positional relationship between the recognition object (R) and the vehicle (50) based on the result of the image recognition obtained by the image recognition unit (13), wherein the error amount estimation unit (12) accumulates the respective errors of the image recognition unit (13), the travel distance calculation unit (14), and the object determination unit (15) to calculate the estimated error amount.

[0084] According to this structure, it is possible to calculate the estimated error amount with high accuracy by taking into account errors in the recognition system related to image recognition and travel distance calculation and errors in the determination system related to determination of the positional relationship between the recognition target object (R) and the vehicle (50). Therefore, the size of the contact assumption area (A) can be appropriately set.

[0085] As one embodiment, the vehicle control unit (16) preferably limits the driving force acting on the wheel (W) to a predetermined contact preparation driving force (T2) or less within the contact assumed area (A).

[0086] According to this structure, when the wheel (W) contacts the wheel chock, it is easy to stop without climbing up the wheel chock.

[0087] The parking assistance system (100) involved in the present disclosure is only required to be able to achieve at least one of the above-mentioned effects.

[0088] Description of Reference Numerals

[0089] 1...ECU; 1M...Program memory; 1P...Processor; 11...Chock position estimation unit; 12...Error estimation unit; 13...Image recognition unit; 14...Driving distance calculation unit; 15...Object determination unit; 16...Vehicle control unit; 20...Drive system; 25...Drive device; 30...Braking system; 35...Braking mechanism; 40...Steering system; 45...Steering mechanism; 50...Vehicle; 51...Accelerator sensor; 52...Gear position sensor; 53...Brake sensor; 54...Speed ​​sensor; 55...Acceleration sensor; 56...Steering angle sensor; 57...Sonar; 58...Camera; 60...Position recognition system; 61...GNSS interface Receiver; 90...In-vehicle network; 100...Parking assistance system; A...Assumed contact area; C...Adjacent vehicle; D1...1st distance; D2...2nd distance; D3...3rd distance; D4...4th distance; Dc...Assumed contact distance; Ds...Base setting distance; E...Parking space; Er...Registered parking space; H...Home; K...Moving path; L...Parking space line; Lf...Top; Pc...Estimated wheel stopper position; Pr...Current position; Pt...Target parking position; Q...Reference point; R...Recognized object; T1...Limited driving force during assistance; T2...Contact preparation driving force; V1...Limited speed during assistance; V2...Contact preparation speed; W...Wheel.

Claims

1. A parking assist system comprising a vehicle control unit configured to control a driving force and a braking force acting on wheels to control the vehicle so as to move a vehicle having the wheels into a parking space. The parking assist system is characterized by further comprising: a wheel chock position estimating unit that estimates a position of the wheel chock in the parking space; and an error amount estimating unit for estimating an error amount of the vehicle position recognition system, The vehicle control unit sets a contact assumption area, which is an area where there is a possibility of contact between the wheel and the wheel stopper, on the vehicle side of the estimated wheel stopper position, based on the estimated wheel stopper position estimated by the wheel stopper position estimating unit, and executes pre-stop control for causing the vehicle to travel at a preset contact preparation speed within the contact assumption area. The vehicle control unit reduces the size of the assumed contact region as the estimated error amount, which is the error amount estimated by the error amount estimating unit, becomes smaller.

2. The parking assistance system according to claim 1, characterized in that The apparatus further includes an image recognition unit that performs image recognition on an image acquired by photographing the surroundings of the vehicle. The vehicle control unit performs a calculation process to calculate the size of an area where there is a possibility of contact with the wheel chock based on the recognition target object recognized by the image recognition unit and a predetermined positional relationship between the recognition target object and the wheel chock. The vehicle control unit sets the size of the assumed contact region based on the sum of the result of the calculation process and the estimated error amount.

3. The parking assistance system according to claim 1 or 2, characterized in that: have: an image recognition unit that performs image recognition on an image acquired by photographing the periphery of the vehicle; a travel distance calculation unit for calculating a travel distance of the vehicle; as well as an object determination unit that determines a positional relationship between a recognition object and the vehicle based on a result of the image recognition obtained by the image recognition unit, The error amount estimating unit calculates the estimated error amount by integrating the errors of the image recognition unit, the travel distance calculation unit, and the object determination unit.

4. The parking assistance system according to claim 1 or 2, characterized in that: The vehicle control unit limits the driving force acting on the wheel in the contact assumed region to be equal to or less than a predetermined contact preparation driving force.

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