Parking assistance system

Abstract

To provide a parking support system which can appropriately move a vehicle to a parking space while securing convenience.SOLUTION: A parking support system includes a vehicle control part, an image recognition part, an object determination part, and a parking curb position estimation part. The vehicle control part executes a pre-stop control which sets a contact supposed area (A) on the basis of an estimated parking curb position (Pc) estimated by the parking curb position estimation part, and allows the vehicle to run at a contact preparation speed within the contact supposed area (A). If a recognized object (R) is a stationary object, the vehicle control part makes the contact supposed area (A) smaller than that in the case in which the recognized object (R) is a movable body.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present invention relates to a parking assistance system that performs vehicle control to move a vehicle into a parking space.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2022-72962 (Patent Document 1) discloses a parking assistance system that performs vehicle control to move a vehicle into a parking space by controlling the driving force and braking force acting on the wheels. The parking assistance system of Patent Document 1 sets a movement path for moving the vehicle into the parking space, gradually reduces the speed of the vehicle according to the remaining distance to the target position, and stops the vehicle as parking completed when the vehicle reaches the target position or the wheels come into contact with the wheel stopper.

[0003] In the parking assistance system of Patent Document 1, the speed is reduced when the vehicle starts to enter the parking space, and then the speed is further reduced when the steering angle becomes zero. Thereby, it is said that the vehicle can be prevented from reaching the wheel stopper vigorously.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, depending on the parking scene, a situation where the steering angle becomes zero at a fairly early stage is also assumed. In such a case, if the speed of the vehicle is greatly reduced from the time when the steering angle becomes zero, the distance and time of traveling at an extremely low vehicle speed will become long, and there is a risk of deterioration in convenience.

[0006] Therefore, there is a need for a parking assistance system that can move vehicles appropriately into parking spaces while ensuring convenience. [Means for solving the problem]

[0007] The parking assistance system related to this disclosure is A parking assistance system comprising a vehicle control unit that controls the driving force and braking force acting on the wheels to move a vehicle equipped with the wheels into a parking space, An image recognition unit that performs image recognition on images acquired by photographing the area around the vehicle, An object determination unit that determines the positional relationship between the recognized object and the vehicle based on the results of the image recognition by the image recognition unit, The system further includes a wheel stop position estimation unit that estimates the position of the wheel stop in the parking space based on the determination result by the object determination unit, The vehicle control unit sets a contact area, which is an area where the wheels may come into contact with the wheel stop, on the vehicle side of the estimated wheel stop position, based on the estimated wheel stop position, which is the position of the wheel stop estimated by the wheel stop position estimation unit, and within the contact area, it performs pre-stop control to drive the vehicle at a preset contact preparation speed. When the vehicle control unit has identified the object to be recognized by the object determination unit, if the recognized object is a stationary object that does not move, it reduces the contact area compared to when the object is a moving object.

[0008] This configuration allows for pre-stop control within a contact-prediction area set based on the estimated wheel stop position, enabling the vehicle to travel at a contact preparation speed and making it easier to avoid the vehicle hitting the wheel stop with excessive force. In this case, if the recognized object recognized by the object determination unit is a fixed object with a small positional error, the contact-prediction area can be made smaller compared to when the recognized object is a moving object with a relatively large positional error, thereby avoiding unnecessarily long distances for the vehicle to travel at low speed. Thus, a parking assistance system can be provided that ensures convenience while appropriately moving the vehicle into the parking space.

[0009] Further features and advantages of the technology relating to this disclosure will become clearer from the following description of exemplary and non-limiting embodiments, with reference to the drawings. [Brief explanation of the drawing]

[0010] [Figure 1] An explanatory diagram showing an example of parking assistance. [Figure 2] A schematic block diagram showing an example of a vehicle system configuration including a parking assist system. [Figure 3] Functional block diagram of the parking assistance system [Figure 4] A schematic diagram showing how to set the contact area. [Figure 5] A graph showing the change in vehicle speed according to the position of the vehicle during parking assistance. [Figure 6] A graph showing the change in driving force according to the position of the vehicle during parking assistance. [Figure 7] A schematic diagram showing an example of setting the size of the contact area. [Figure 8] A schematic diagram showing an example of setting the size of the contact area. [Figure 9] A schematic diagram showing an example of setting the size of the contact area. [Figure 10] A schematic diagram showing an example of setting the size of the contact area. [Modes for carrying out the invention]

[0011] An embodiment of the parking support system will be described with reference to the drawings. The explanatory diagrams of FIG. 1 illustrate one form of parking support when parking the vehicle 50, respectively. Further, the block diagram of FIG. 2 schematically shows an example of the system configuration of the vehicle 50 including the parking support system 100. The parking support system 100 of the present embodiment performs vehicle control for moving the vehicle 50 to the parking space E by controlling the driving force and braking force acting on the wheels W and controlling the steering angle.

[0012] In the present embodiment, the parking support system 100 parks the vehicle 50 in the parking space E by automatic driving. Note that the driving may be in a form where the driver manually steers based on the guidance by the parking support system 100 and only the driving and braking are performed by automatic driving, that is, semi-automatic driving.

[0013] As shown in FIG. 2, the parking support system 100 is realized by the cooperation of the ECU (electronic control unit) 1 as the core with other systems and various sensors. The ECU 1 includes a processor 1P such as a microcomputer, a microprocessor, a DSP (digital signal processor), a program memory 1M in which software such as programs and parameters is stored, and various other electronic components.

[0014] The processor 1P is the core hardware of the ECU 1, and the vehicle control unit is realized by the cooperation of various hardware with the processor 1P as the core and software such as programs stored in the program memory 1M. Then, with the ECU 1 as the core, other systems such as the drive system 20, the brake system 30, the steering system 40, the position recognition system 60, and various sensors and peripheral devices indicated by the signs "51" to "58", "61" cooperate with the ECU 1 to realize the parking support system 100.

[0015] In the following, various functional units that make up the parking support system 100 will be described. Each functional unit may be realized by a plurality of hardware components, or may be realized by the cooperation of at least one hardware component and software, and does not necessarily need to be configured as an independent component.

[0016] As shown in FIG. 1, the parking support system 100 moves the vehicle 50 to the parking target position Pt and stops it based on the parking target position Pt set in the parking space E and the current position Pr of the vehicle 50. The parking target position Pt and the current position Pr correspond to the coordinates in the coordinate system (parking support coordinate system) when the parking support system 100 performs parking support (vehicle control).

[0017] The symbol "Q" shown in FIG. 1 indicates the reference point on the vehicle 50 when identifying the position of the vehicle 50. Also, the current position Pr corresponds to the coordinates where the reference point Q is located in the parking support coordinate system. The parking target position Pt indicates the coordinates where the reference point Q of the vehicle 50 is located when the vehicle 50 is properly positioned in the parking space E. The parking support system 100 calculates the movement trajectory of the reference point Q when the vehicle 50 moves from the current position Pr to the parking target position Pt based on the current position Pr and the parking target position Pt, and sets this as the movement path K.

[0018] The parking support system 100 performs vehicle control so that the reference point Q moves along the movement path K from the current position Pr. When the reference point Q reaches the parking target position Pt, that is, when the current position Pr and the parking target position Pt coincide, the parking support system 100 stops the vehicle 50 because the vehicle 50 will be properly positioned within the parking space E. Note that the parking target position Pt may be the estimated wheel stop position Pc described later, and the reference point Q may be the position of the axis center of the rear wheel.

[0019] Figure 1 illustrates a typical parallel parking maneuver. For example, the driver drives past the parking space E, turns the steering wheel in the opposite direction to the parking space E, and stops the vehicle 50 with a slight turn. This position can be considered the starting position for reversing towards the parking space E. Although the amount of steering required to move to the target parking position Pt will be larger, the vehicle 50 may also be stopped while moving straight without turning the steering wheel in this manner. Alternatively, before starting to move from the stopping position to the target parking position Pt, the direction of the steering wheels may be changed by so-called stationary steering in cooperation with the steering system 40.

[0020] It goes without saying that the parking assistance system 100 of this embodiment can be applied not only to parallel parking but also to so-called parallel parking.

[0021] When the driver moves the vehicle 50 forward, it is preferable for the parking assist system 100 to guide the driver regarding the direction of travel and the stopping position (reverse starting position). For example, it is preferable for the system to guide the driver through displays on the in-cabin display or voice guidance, and for the driver to move the vehicle 50 to the reverse starting position by operating the accelerator pedal, brake pedal, steering wheel, etc. (not shown).

[0022] The parking assist system 100 may inform the driver that automatic driving, including automatic steering, is possible when the vehicle 50 reaches the reversing starting position. When the driver instructs the start of vehicle control, for example by touching a start button on a touch panel on a display in the vehicle interior, the driving operations of the vehicle 50, including steering, are entrusted to the parking assist system 100. Subsequently, the parking assist system 100 moves the vehicle 50 to the parking target position Pt by automatic driving.

[0023] As shown in Figure 2, the vehicle 50 is equipped with an ECU 1, which is the core of the parking assistance system 100, as well as 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 unit 25 that drives the wheels W. The drive unit 25 includes, for example, an internal combustion engine, a rotating electric machine, a gear mechanism, and an engagement device for disconnecting and connecting power transmission between rotating members, none of which are 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 among the wheels W. The position recognition system 60 is a system that recognizes the position (current position Pr) of the vehicle 50.

[0024] The vehicle 50 is also equipped with various sensors and peripheral devices, including an accelerator sensor 51, a shift 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 the GNSS receiver 61.

[0025] The accelerator sensor 51 is a sensor that detects the amount of operation of the accelerator pedal by the driver. The shift position sensor 52 is a sensor that detects an instruction input that indicates the operating mode of the drive unit 25, such as a gear shift (including reverse and parking) indicated by a shift 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 travel speed of the vehicle 50, i.e., the rotational speed of the wheels W. The acceleration sensor 55 is a sensor that detects the acceleration of the vehicle 50, and in this embodiment, the acceleration sensor 55 can also detect, for example, the inclination angle and 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, and preferably the amount of operation is detected as the steering angle of the vehicle 50.

[0026] The sonar 57 is installed at multiple locations on the vehicle 50 to detect the presence or absence of obstacles in the vicinity of the vehicle 50. Preferably, the sonar 57 is an active sonar. In addition to the sonar 57, other obstacle sensors such as laser radar may also be provided. The camera 58 is installed at multiple locations on the vehicle 50 to acquire images of the area around the vehicle 50. The GNSS receiver 61 receives signals from GNSS satellites.

[0027] The sensors and peripheral devices indicated by symbols "51" to "58" and "61," including the aforementioned ECU1 (parking assistance system 100), drive system 20, brake system 30, steering system 40, and position recognition system 60, are connected to each other so as to be able to communicate with one another via an in-vehicle network 90, such as a CAN (controller area network).

[0028] For example, the drive system 20 controls the drive unit 25 in cooperation with an accelerator sensor 51, a shift position sensor 52, a brake sensor 53, a speed sensor 54, an acceleration sensor 55, a steering angle sensor 56, etc., via the in-vehicle network 90. ​​The brake system 30 controls the brake mechanism 35 in cooperation with the brake sensor 53 via the in-vehicle network 90. ​​The steering system 40 controls the steering mechanism 45, including the steering wheel and steering wheels, in cooperation with the steering angle sensor 56. 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. In this embodiment, the position recognition system 60 recognizes the position of the vehicle 50 (current position Pr) based on the GNSS signal as well as information obtained from the speed sensor 54, the steering angle sensor 56, the camera 58, etc.

[0029] As shown in Figure 3, the parking assistance system 100 (ECU1) comprises a wheel stop position estimation unit 11, an error amount estimation unit 12, an image recognition unit 13, a mileage calculation unit 14, an object determination unit 15, and a vehicle control unit 16. Each of these functional units has a calculation unit that performs various processing on the input data, which is composed of hardware, software (program), or both. The configuration shown in Figure 3 is an illustrative and conceptual block diagram and does not limit the actual physical configuration of the ECU1.

[0030] The wheel stop position estimation unit 11 estimates the position of the wheel stop in the parking space E. The error amount estimation unit 12 estimates the error amount of the vehicle 50 position recognition system 60. The image recognition unit 13 performs image recognition on images acquired by photographing the area around the vehicle 50. The mileage calculation unit 14 calculates the mileage of the vehicle 50. The object determination unit 15 determines the positional relationship between the recognized object R and the vehicle 50 based on the image recognition results from the image recognition unit 13. The vehicle control unit 16 controls the driving force and braking force acting on the wheels W to perform vehicle control in order to move the vehicle 50 equipped with wheels W to the parking space E.

[0031] The wheel stop position estimation unit 11 estimates the position of the wheel stop in the parking space E. The wheel stop position estimation unit 11 estimates the position of the wheel stop that is assumed to be installed in the parking space E where the vehicle 50 is to be parked, based on the parking assistance. In this embodiment, the wheel stop position estimation unit 11 does not directly recognize the wheel stop and determine its position, but rather estimates the position of the wheel stop based on other objects that exist in the vicinity of the parking space E. Examples of other objects that exist in the vicinity of the parking space E include fixed objects such as the parking space line L that demarcates the parking space E, as shown in Figure 4. The wheel stop position estimation unit 11 estimates the position of the wheel stop by assuming that a wheel stop exists, regardless of whether a wheel stop actually exists in the parking space E or not.

[0032] The wheel stop position estimation unit 11 estimates the wheel stop position to be a distance Ds behind the tip Lf of the parking space line L recognized by the image recognition unit 13, for example, using the tip Lf as a reference. In this embodiment, the wheel stop position estimated by the wheel stop position estimation unit 11 is called the "estimated wheel stop position Pc". Here, the reference setting distance Ds can be set to, for example, the sum of the average wheelbase and the average front overhang of a typical vehicle 50.

[0033] Alternatively, the estimated wheel stop position Pc may be determined by considering other vehicles 50, such as adjacent vehicle C (see Figure 7), located in the adjacent parking space E, as other objects located near the parking space E. In this case, the wheel stop position estimation unit 11 uses, for example, the position of the front end of adjacent vehicle C recognized by the image recognition unit 13 as a reference, and sets the estimated wheel stop position Pc to a position located a reference distance Ds backward from the front end of said adjacent vehicle C.

[0034] The basic operation of the vehicle control unit 16 related to parking assistance in this embodiment will be explained with reference to Figures 4 to 6. As shown in Figure 4, the vehicle control unit 16 sets a contact assumption area A, which is an area where the wheels W may come into contact with the wheel stop, on the side (front side) of the vehicle 50 than the estimated wheel stop position Pc obtained by the wheel stop position estimation unit 11. In this embodiment, the vehicle control unit 16 sets the area between the estimated wheel stop position Pc and a position advanced forward by a predetermined contact assumption distance Dc from the estimated wheel stop position Pc as the contact assumption area A.

[0035] In this way, the vehicle control unit 16 performs calculation processing to calculate the size of the expected contact area A based on the recognized object R (parking space line L, adjacent vehicle C, etc.) recognized by the image recognition unit 13 and the predetermined positional relationship between the recognized object R and the wheel stop (a positional relationship determined according to the reference setting distance Ds and the expected contact distance Dc, with the position of the tip as the reference).

[0036] As shown in Figure 5, the vehicle control unit 16 drives the vehicle 50 at a preset support speed limit V1 while parking assistance is being performed. In Figure 5, the horizontal axis indicates the position of the vehicle 50, and the origin corresponds to the starting position of the parking assistance. The support speed limit V1 is set to a speed that allows the vehicle 50 to be safely moved into the parking space E. The support speed limit V1 can be set to, for example, about 1 to 4 km / h.

[0037] The vehicle control unit 16 executes pre-stop control when the vehicle 50, which is performing parking assistance, enters the expected contact area A. The entry of the vehicle 50 into the expected contact area A can be determined based on the distance between the vehicle 50's reference point Q (e.g., the position of the rear wheel axis) obtained from the position recognition system 60 and the estimated wheel stop position Pc becoming less than or equal to the expected contact distance Dc. Here, pre-stop control is a control performed preemptively in preparation for stopping before the vehicle 50's wheels W make contact with the wheel stop. In pre-stop control, the vehicle control unit 16 drives the vehicle 50 at a pre-set contact preparation speed V2, which is lower than the assistance speed limit V1. The contact preparation speed V2 is set to a speed that prevents occupants from feeling uncomfortable from the shock when the wheels W make contact with the wheel stop. The contact preparation speed V2 can be set to, for example, 0-1 km / h.

[0038] Furthermore, as shown in Figure 6, the vehicle control unit 16 controls the drive system 20 to drive the vehicle 50 with a preset limited driving force T1 during parking assistance. In Figure 6, as in Figure 5, the horizontal axis indicates the position of the vehicle 50, and the origin corresponds to the starting position of the parking assistance. The limited driving force T1 during parking assistance is set to a driving force that allows the vehicle 50 to move appropriately within the parking space E, and prevents the wheels W from going over the wheel chocks when they come into contact with them.

[0039] In the pre-stop control performed when the vehicle 50 enters the anticipated contact area A, the vehicle control unit 16 controls the drive system 20 to drive the vehicle 50 with a contact preparation drive force T2, which is set to a value lower than the support limit drive force T1. The contact preparation drive force T2 is set to a drive force that allows the vehicle to stop without shock when the wheels W come into contact with the wheel chocks.

[0040] The parking assistance system 100 (ECU1) of this embodiment is characterized by its ability to variably set the size of the contact area A depending on the situation. This point will be explained below with reference to Figures 7 to 10.

[0041] As described above, the contact area A is set based on the estimated wheel stop position Pc obtained by the wheel stop position estimation unit 11, and the estimated wheel stop position Pc is determined based on the recognized object R (parking space line L, adjacent vehicle C, etc.) recognized by the image recognition unit 13. It is presumed that there is a difference in the reliability of the estimated wheel stop position Pc, which serves as the basis for setting the contact area A, depending on whether it is determined based on a fixed object such as a parking space line L or on a moving object such as an adjacent vehicle C. It is presumed that when the estimated wheel stop position Pc is determined based on a fixed object such as a parking space line L, a more reliable estimated wheel stop position Pc is obtained compared to when it is determined based on a moving object such as an adjacent vehicle C.

[0042] Therefore, in this embodiment, when the recognized object R is a fixed object such as a parking space line L, the vehicle control unit 16 reduces the contact area A compared to when the recognized object R is a moving object such as an adjacent vehicle C. Figure 7 shows an example of the contact area A set when the recognized object R is an adjacent vehicle C. In this figure, the contact area A is set in the area between the estimated wheel stop position Pc and a position advanced forward by a first distance D1 from the estimated wheel stop position Pc. On the other hand, Figure 8 shows an example of the contact area A set when the recognized object R is a parking space line L. In this figure, the contact area A is set in the area between the estimated wheel stop position Pc and a position advanced forward by a second distance D2 which is shorter than the first distance D1 from the estimated wheel stop position Pc.

[0043] Furthermore, the location information (current location Pr) of the vehicle 50 acquired by the location recognition system 60 is not necessarily accurate and contains a certain amount of error. This amount of error is not uniform for all vehicles 50, but can vary depending on the manufacturer, model, and trim level. Naturally, the smaller the amount of error, the more accurate the location information (current location Pr) of the vehicle 50.

[0044] Therefore, in this embodiment, the error amount estimation unit 12 estimates the error amount of the vehicle 50's position recognition system 60, and the vehicle control unit 16 reduces the contact assumption area A as the estimated error amount, which is the error amount estimated by the error amount estimation unit 12, decreases. As described above, in this embodiment, the position information (current position Pr) of the vehicle 50 is obtained based on the GNSS signal and information obtained from the speed sensor 54, steering angle sensor 56, and camera 58. Of these, the error in the GNSS signal is basically uniform for all vehicles 50 if the type of GNSS is the same, whereas the information obtained from the speed sensor 54, steering angle sensor 56, and camera 58, and the judgment results based on them, may differ for each vehicle 50.

[0045] For example, the image recognition unit 13 performs image recognition on images acquired by the camera 58 that photograph the area around the vehicle 50, but the image recognition itself may contain errors. Also, the mileage calculation unit 14 calculates the mileage of the vehicle 50 during parking assistance based on information obtained from the speed sensor 54, but the calculated mileage may also contain errors due to the detection errors of the speed sensor 54. Furthermore, the object determination unit 15 determines the positional relationship between the recognized object R and the vehicle 50 based on the image recognition results from the image recognition unit 13, but as mentioned above, the image recognition may contain errors, so the determination result regarding the positional relationship between the recognized object R and the vehicle 50 may also contain errors. Taking these circumstances into consideration, the error amount estimation unit 12 of this embodiment calculates an estimated error amount by accumulating the errors of the image recognition unit 13, the mileage calculation unit 14, and the object determination unit 15.

[0046] The vehicle control unit 16 adjusts the size of the contact area A to take into account the estimated error amount, based on the results of the calculation process described with reference to Figure 4 regarding the setting of the contact area A (the area from the estimated wheel stop position Pc forward by the estimated contact distance Dc). The adjustment of the size of the contact area A to take into account the estimated error amount may be performed stepwise for each of the multiple stages in which the estimated error amount is divided, or it may be performed linearly based on a predetermined relational expression. In any case, the vehicle control unit 16 reduces the contact area A as the estimated error amount calculated by the error amount estimation unit 12 decreases.

[0047] Figure 9 shows an example of the adjusted contact area A when the recognized object R is a parking space line L and the estimated error calculated by the error estimation unit 12 is relatively small. In this figure, the contact area A is set to be the area between the estimated wheel stop position Pc and a position that is a third distance D3 shorter than the second distance D2, moving forward from the estimated wheel stop position Pc. On the other hand, Figure 10 shows an example of the adjusted contact area A when the recognized object R is a parking space line L and the estimated error calculated by the error estimation unit 12 is relatively large. In this figure, the contact area A is set to be the area between the estimated wheel stop position Pc and a position that is a fourth distance D4 longer than the second distance D2, moving forward from the estimated wheel stop position Pc.

[0048] In Figures 9 and 10, an example is shown where the recognized object R is the parking space line L. However, similarly, when the recognized object R is an adjacent vehicle C, the vehicle control unit 16 reduces the contact area A as the estimated error decreases. In this case, when the estimated error is relatively small, the contact area A is set to the area between the estimated wheel stop position Pc and a position that is a fifth distance shorter than the first distance D1 moving forward from the estimated wheel stop position Pc. On the other hand, when the estimated error is relatively large, the contact area A is set to the area between the estimated wheel stop position Pc and a position that is a sixth distance longer than the first distance D1 moving forward from the estimated wheel stop position Pc.

[0049] As described above, the parking assistance system 100 of this embodiment is A parking assistance system 100 comprising a vehicle control unit 16 that controls the driving force and braking force acting on the wheels W to move a vehicle 50 equipped with wheels W into a parking space E, An image recognition unit 13 performs image recognition on images acquired by photographing the area around the vehicle 50, Based on the image recognition results from the image recognition unit 13, the object determination unit 15 determines the positional relationship between the recognized object R and the vehicle 50, The system further includes a wheel stop position estimation unit 11 that estimates the position of the wheel stop in the parking space E based on the determination result by the object determination unit 15, The vehicle control unit 16 sets a contact scenario area A, which is an area where the wheels W may come into contact with the wheel chocks, on the side of the vehicle 50 from the estimated wheel chock position Pc, which is the position of the wheel chocks estimated by the wheel chock position estimation unit 11, and within the contact scenario area A, it performs pre-stop control to drive the vehicle 50 at a preset contact preparation speed V2. When the vehicle control unit 16 has recognized an object R by the object determination unit 15, if the recognized object R is a stationary object that does not move, it reduces the contact area A compared to when the object R is a moving object.

[0050] With this configuration, by performing pre-stop control within the expected contact area A, which is set based on the estimated wheel stop position Pc, the vehicle 50 is driven at a contact preparation speed V2, making it easier to avoid the vehicle 50 hitting the wheel stop with excessive force. In this case, if the recognized object R recognized by the object determination unit 15 is a fixed object that can be considered to have a small position error, the expected contact area A can be made smaller compared to when it is a moving object that can be said to have a relatively large position error, thereby avoiding the vehicle 50 having to travel an unnecessarily long distance at low speed. Thus, a parking assistance system 100 can be provided that can move the vehicle 50 appropriately to the parking space E while ensuring convenience.

[0051] As one aspect, The fixed elements include the parking space lines L that demarcate the parking space E. Preferably, the moving object includes an adjacent vehicle C, which is another vehicle 50 located in the adjacent parking space E.

[0052] While an adjacent vehicle C in the adjacent parking space E may not be parked in an ideal position, the parking space line L is in a fixed position in relation to the parking space E. Therefore, the estimated position of the wheel stop based on the parking space line L generally has higher positional accuracy than the estimated position of the wheel stop based on the adjacent vehicle C. Thus, based on the above configuration, when the recognized object R recognized by the object determination unit 15 is the parking space line L, the contact area A is made smaller compared to when it is the adjacent vehicle C, thereby appropriately avoiding the vehicle 50 having to travel an unnecessarily long distance at low speed.

[0053] As one aspect, The system further includes an error estimation unit 12 for estimating the error amount of the vehicle 50's position recognition system 60. The vehicle control unit 16 preferably reduces the contact assumption area A as the estimated error amount, which is the error amount estimated by the error amount estimation unit 12, decreases.

[0054] With this configuration, by taking into account the estimation error of the vehicle 50's position recognition system 60 and reducing the contact assumption area A as the error decreases, it is possible to appropriately avoid unnecessarily increasing the distance the vehicle 50 travels at low speed.

[0055] As one aspect, The vehicle control unit 16 preferably limits the driving force applied to the wheels W within the contact area A to a preset contact preparation driving force T2 or less.

[0056] This configuration makes it easier to stop the vehicle without the wheel W running over the wheel chock when it comes into contact with it.

[0057] [Other Embodiments] (1) In the above embodiment, a configuration was described in which the wheel stop position estimation unit 11 estimates the position of the wheel stop based on other objects located near the parking space E. However, the configuration is not limited to such a configuration, and for example, the wheel stop position estimation unit 11 may detect the wheel stop itself using a laser radar or the like and then estimate the position of the wheel stop as an estimated position that includes errors.

[0058] (2) In the above embodiment, the description mainly assumed a configuration in which the contact area A is set as a two-dimensional area having a fixed length in the path direction and a fixed length in the width direction. However, the description is not limited to such a configuration, and the contact area A may be a one-dimensional area defined only by a fixed length in the path direction.

[0059] (3) In the above embodiment, the recognition target object R that serves as a reference for determining the estimated wheel stop position Pc was described as a configuration in which the parking space line L or adjacent vehicle C is used. However, the configuration is not limited to such one, and other items such as walls, fences, or coin parking flap plates may also be used as the recognition target object R, as long as they are expected to exist in the vicinity of the wheel stop in the parking space E and can be recognized by the image recognition unit 13.

[0060] (4) In the above embodiment, a configuration was described in which the vehicle control unit 16 adjusts the size of the assumed contact area A according to whether the object to be recognized R is a fixed object or a moving object, and according to the estimated error amount obtained by the error amount estimation unit 12. However, the vehicle control unit 16 is not limited to such a configuration, and may adjust the size of the assumed contact area A according only to whether the object to be recognized R is a fixed object or a moving object.

[0061] (5) In the above embodiment, the vehicle control unit 16 was described as having a configuration in which it reduces the contact area A when the estimated error amount obtained by the error amount estimation unit 12 is relatively small, and increases the contact area A when the estimated error amount is relatively large. However, the vehicle control unit 16 is not limited to such a configuration, and may simply reduce the contact area A when the estimated error amount obtained by the error amount estimation unit 12 is relatively small.

[0062] (6) In the above embodiment, the vehicle control unit 16 was described as having a configuration in which, in pre-stop control performed when the vehicle 50 enters the contact-preparation area A, the vehicle speed is limited to the contact-preparation speed V2 and the driving force is limited to the contact-preparation driving force T2. However, the configuration is not limited to such a configuration, and in pre-stop control, the vehicle control unit 16 only needs to limit the vehicle speed to the contact-preparation speed V2, and limiting the driving force is not essential. Note that the vehicle speed control and driving force control during pre-stop control may be performed by feedforward control or feedback control, respectively.

[0063] (7) In the above embodiment, the vehicle control unit 16 has been described in advance as a configuration in which the vehicle speed is already below the contact preparation speed V2 when the vehicle 50 reaches the contact area A. However, the vehicle control unit 16 may also begin to decelerate the vehicle 50 after the vehicle 50 has reached the contact area A. The same considerations apply to the limiting of the driving force.

[0064] (8) The configurations disclosed in each of the above-described embodiments (including the above-described embodiments and other embodiments; the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, as long as this does not cause a conflict. With respect to other configurations, the embodiments disclosed herein are illustrative in all respects and can be modified as appropriate without departing from the spirit of the disclosure. [Explanation of symbols]

[0065] 1: ECU, 1M: Program memory, 1P: Processor, 11: Wheel stop position estimation unit, 12: Error amount estimation unit, 13: Image recognition unit, 14: Distance calculation unit, 15: Object determination unit, 16: Vehicle control unit, 20: Drive system, 25: Drive unit, 30: Brake system, 35: Brake mechanism, 40: Steering system, 45: Steering mechanism, 50: Vehicle, 51: Accelerator sensor, 52: Shift 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 receiver, 90: In-vehicle network, 100: Parking assist system, A: Contact area, C: Adjacent vehicle, D1: First distance, D2: Second distance, D3: Third distance, D4: Fourth distance, Dc: Contact distance, Ds: Reference distance, E: Parking space, Er: Registered parking space, H: Home, K: Travel route, L: Parking line, Lf: Front, Pc: Estimated wheel stop position, Pr: Current position, Pt: Parking target position, Q: Reference point, R: Recognized object, T1: Assisted limited driving force, T2: Contact preparation driving force, V1: Assisted limited speed, V2: Contact preparation speed, W: Wheel

Claims

1. A parking assistance system comprising a vehicle control unit that controls the driving force and braking force acting on the wheels to move a vehicle equipped with the wheels into a parking space, An image recognition unit that performs image recognition on images acquired by photographing the area around the vehicle, An object determination unit that determines the positional relationship between the recognized object and the vehicle based on the results of the image recognition by the image recognition unit, The system further includes a wheel stop position estimation unit that estimates the position of the wheel stop in the parking space based on the determination result by the object determination unit, The vehicle control unit sets a contact area, which is an area where the wheels may come into contact with the wheel stop, on the vehicle side of the estimated wheel stop position, based on the estimated wheel stop position, which is the position of the wheel stop estimated by the wheel stop position estimation unit, and within the contact area, it performs pre-stop control to drive the vehicle at a preset contact preparation speed. A parking assistance system in which, when the vehicle control unit recognizes the object to be recognized by the object determination unit, if the recognized object is a stationary object that does not move, the contact area is reduced compared to when the object is a moving object.

2. The fixed object includes parking space lines that demarcate the parking space. The parking assistance system according to claim 1, wherein the moving body includes adjacent vehicles, which are other vehicles located in the adjacent parking space.

3. The system further comprises an error estimation unit for estimating the error amount of the vehicle's position recognition system, The parking assistance system according to claim 1 or 2, wherein the vehicle control unit reduces the contact area as the estimated error amount, which is the error amount estimated by the error amount estimation unit, decreases.

4. The parking assistance system according to claim 1 or 2, wherein the vehicle control unit limits the driving force applied to the wheels within the contact area to a preset contact preparation driving force or less.

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