Parking assistance device

Abstract

To provide a parking support device, which in parking an own vehicle in a parking space utilizing a parking support function, can reduce inconvenience that the device wrongly guides the own vehicle to a walkway in which parking is prohibited, even in a situation where the device cannot recognize a parking frame.SOLUTION: A parking support device 1 comprises an operation support control unit 11. The operation support control unit 11 obtains environment information about a circumference of an own vehicle M from sensors 21, 26-28; determines a parking space width Wp between parked vehicles Pv parked in a parking lot on the basis of the environment information; when the parking space width Wp is larger than a required parking width Ws of a virtual parking frame 41 that is required in parking the own vehicle M, sets the virtual parking frame 41 in the parking space; and when the parked vehicles Pv or marks 51 of shoes are not facing one side other than the own vehicle M side of the virtual parking frame 41, estimates that the virtual parking frame 41 is not the parking space.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a parking assistance device that reduces the inconvenience of erroneously determining sidewalks or traffic lanes within a parking lot as parking spaces in a parking lot where parking frames drawn on the road surface cannot be recognized. [Background technology]

[0002] A parking assistance device that assists a driver in parking a vehicle within a parking space set in a parking lot and reduces the burden on the driver has been known. In this type of parking assistance device, while the driver is operating the vehicle within the parking lot, a control unit detects available parking space candidates and displays the candidate parking spaces on a monitor. The driver selects a desired parking space from the displayed candidate parking spaces.

[0003] Then, the control unit sets a parking guidance route for parking the vehicle in the parking space selected by the driver, and guides the vehicle to the parking space along the parking guidance route. Alternatively, the driver operates the vehicle and parks it in the parking space along the parking guidance route displayed on the monitor.

[0004] In the above-mentioned conventional parking assistance device, when parking the vehicle in a parking space, first, detects available parking spaces. Therefore, if the road surface of the parking lot is covered with snow or mud remaining after flooding, and the parking space drawn on the road surface cannot be recognized, it becomes difficult for the parking assistance device to construct a parking guidance route that leads the vehicle to the parking space.

[0005] A driver needs parking assistance from a parking assistance device more in poor environments where it is difficult to recognize a parking space than in good environments. For example, Patent Document 1 (JP 2006-7875 A) discloses a technology that determines whether there is a space between parallel parked vehicles where the driver's vehicle can park by first calculating the gap distance between the two parked vehicles by subtracting half the width of each parked vehicle from the distance between the centers of the two parked vehicles in the vehicle width direction, and then determining that parking is possible if this gap distance is wider than the vehicle width of the driver's vehicle plus a predetermined margin. The technology then discloses that the center of this gap processing is set to the center of the intended parking area and the driver's vehicle is guided. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-7875 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when parking one's vehicle in a parking lot of a store or the like, the parking position changes depending on the vehicles already parked there (parked vehicles), making it difficult to always park in the same place. In addition, the layout of parking spaces set up in the parking lot also differs from store to store.

[0008] Therefore, as disclosed in Cited Document 1, even if a gap distance between two parallel parked vehicles is detected that allows the vehicle to be parked, if the road surface is covered with snow or mud remaining after flooding, the parking frame drawn on the road surface cannot be recognized, and the gap may not be a parking space but a sidewalk or traffic lane where parking is prohibited.

[0009] The technology disclosed in the above-mentioned Cited Document 1 merely determines whether the vehicle can be parked based on the gap distance between adjacent parked vehicles. Therefore, the control unit may guide the vehicle into a sidewalk or lane between parking spaces where parking is prohibited.

[0010] To provide a parking assistance device that can reduce the inconvenience of guiding one's own vehicle erroneously onto a sidewalk where parking is prohibited, even in a situation where a parking frame cannot be recognized when one attempts to park one's own vehicle in a parking space by using a parking assistance function. [Means for solving the problem]

[0011] The present invention relates to a parking assistance device that guides a host vehicle to an available parking space in a parking lot, and includes an environmental information acquisition unit that acquires environmental information around the host vehicle, a storage unit that stores a virtual parking frame required for parking the host vehicle, a parking interval calculation unit that calculates the width of a parking space between landmarks based on the environmental information acquired by the environmental information acquisition unit, a parking width comparison unit that compares the width of the parking space calculated by the parking interval calculation unit with the width of the virtual parking frame stored in the storage unit, a virtual parking frame setting unit that sets the virtual parking frame within the parking space when the parking width comparison unit determines that the width of the parking space is wider than the width of the virtual parking frame, and All a parking space determination unit that determines whether the target or shoe print recognized based on the environmental information acquired by the environmental information acquisition unit faces the outside of a side of the virtual parking frame set by the virtual parking frame setting unit; All The system is provided with a parking space setting unit that sets the virtual parking frame as the parking space when it is determined that the target object or the shoe print faces the outside of the side, and a parking assistance unit that guides the vehicle to the parking space set by the parking space setting unit. [Effects of the Invention]

[0012] According to the present invention, when guiding the vehicle to a parking space in a parking lot, first, the width of the parking space calculated based on the environmental information acquired by the environmental information acquisition unit is compared with the width of the virtual parking frame required to park the vehicle, which is stored in advance. If it is determined that the width of the parking space is wider than the width of the virtual parking frame, a virtual parking frame is set within this parking space, and it is checked whether or not there are landmarks or shoe prints facing the outside of the three sides of this virtual parking frame excluding the side facing the vehicle. If there are landmarks or shoe prints facing the three sides, this virtual parking frame is set as a parking space where the vehicle can be parked, and the vehicle is guided to this parking space. Therefore, even in a situation where the virtual parking frame cannot be recognized, the inconvenience of erroneously guiding the vehicle to a sidewalk where parking is prohibited can be reduced. [Brief explanation of the drawings]

[0013] [Figure 1] Schematic diagram of parking assistance system [Figure 2] Flowchart showing a parking assistance control routine [Figure 3] Flowchart showing parking assistance mode execution subroutine [Figure 4] Flowchart showing the parking assistance subroutine in adverse environments (part 1) [Figure 5] Flowchart showing the parking assistance subroutine in adverse environments (part 2) [Figure 6A] FIG. 10 is an explanatory diagram illustrating a case where the width between the virtual parking frame of the vehicle and the adjacent parked vehicle is the same; [Figure 6B] FIG. 10 is an explanatory diagram illustrating a case where the distance between adjacent parked vehicles is wider than the virtual parking frame of the host vehicle. [Figure 6C] FIG. 10 is an explanatory diagram illustrating a case where the distance between adjacent parked vehicles is narrower than the virtual parking frame of the host vehicle. [Figure 7] Aerial view showing the status of the search for available parking spaces [Figure 8] An explanatory diagram showing available parking spaces displayed on the HMI monitor [Figure 9] Aerial view of the entire parking lot showing available parking spaces [Figure 10] FIG. 10 is a bird's-eye view showing how the number of shoe prints in a virtual parking space is counted. [Figure 11] A bird's-eye view showing a virtual parking space with parked vehicles facing three sides. [Figure 12] A bird's-eye view showing a virtual parking space with parked vehicles facing the two left and right sides and shoe prints facing the back side. [Figure 13] A bird's-eye view showing a virtual parking space with parked vehicles facing two adjacent sides and shoe prints facing one side. [Figure 14] A bird's-eye view showing a virtual parking space with shoe prints facing two adjacent sides and a parked vehicle facing one side. [Figure 15] A bird's-eye view showing the virtual parking space with two sides, one on the vehicle's side and one on the back, open. [Figure 16] A bird's-eye view showing shoe prints crossing a virtual parking space DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described below with reference to the drawings. A parking assistance device 1 shown in FIG. 1 is mounted on a host vehicle M (see FIGS. 7 and 9). The parking assistance device 1 includes a driving assistance control unit 11. The driving assistance control unit 11 is configured with a microcontroller including a CPU, RAM, ROM, a rewritable nonvolatile memory (flash memory or EEPROM), and peripheral devices. The ROM stores programs and fixed data required for the CPU to execute various processes. The RAM serves as a work area for the CPU, temporarily storing various data for the CPU. The CPU is also called an MPU (microprocessor) or a processor. A GPU (graphics processing unit) or a GSP (graph streaming processor) may be used instead of the CPU. Alternatively, a CPU, a GPU, and a GSP may be selectively combined.

[0015] When the driver sets a desired assistance mode, the driving assistance control unit 11 performs driving assistance in the corresponding assistance mode. The driving assistance control unit 11 has a driving assistance mode and a parking assistance mode as assistance modes.

[0016] In the driving assistance mode, the host vehicle M performs map matching on a road map in a road map database 22b based on host vehicle position information acquired by a GNSS sensor 22a of a map locator unit 22 (described later), and autonomously drives the host vehicle M along a predetermined target route in sections where autonomous driving is possible. In addition, in this driving assistance mode, on roads where autonomous driving is difficult, well-known adaptive cruise control (ACC), active lane keep (ALK), and lane departure prevention (LDP) controls are executed, and when the host vehicle M stays within the lane and detects a preceding vehicle, driving control is executed to follow the preceding vehicle.

[0017] On the other hand, in the parking assistance mode, when the driver selects this mode when the vehicle M enters a parking lot and drives through the parking lot by himself, the driving assistance control unit 11 searches for available parking spaces and notifies the driver. Then, when the driver selects a desired parking space from the available parking spaces, the vehicle M is automatically parked in the selected parking space. Alternatively, a parking guidance route for parking the vehicle M into the parking space is superimposed on a surrounding image and an overhead image of the vehicle M displayed on the HMI monitor 31 (described later), thereby providing parking assistance when the driver parks by himself.

[0018] In addition, the input side of the driving assistance control unit 11 is connected to sensor units that acquire driving status information (including position and direction) of the vehicle M and information on the surrounding environment of the vehicle M, which are required when executing the driving assistance mode and parking assistance mode.

[0019] In this embodiment, the sensor units required to execute each assistance mode include a forward recognition sensor 21, a map locator unit 22, an autonomous driving sensor 23, a brake sensor 24 that detects depression of the brake pedal and turns ON, a select position sensor 25 that detects the select position selected by the driver operating the select lever, a rear sensor 26 that acquires environmental information behind the host vehicle M, left and right front side sensors 27, left and right rear side sensors 28, and left and right front side recognition cameras 29. The sensors 21, 26 to 29 constitute an environmental information acquisition unit of the present invention.

[0020] The forward recognition sensor 21 is an image sensor, and in this embodiment, it has a stereo camera consisting of a main camera 21a and a sub-camera 21b, each of which uses a CCD, CMOS, or the like as an imaging element, and an image processing unit (IPU) 21c. Both cameras 21a, 21b have a predetermined baseline length and are installed horizontally, for example, above the rearview mirror at the front of the vehicle, at a position close to the windshield and equidistant to the left and right from the center in the vehicle width direction. The forward recognition sensor 21 processes images of environmental information of a predetermined area captured by both cameras 21a, 21b using the IPU 21c, and then transmits the images to the driving assistance control unit 11.

[0021] The map locator unit 22 also includes a GNSS (Global Navigation Satellite System) sensor 22a and a road map database 22b. The GNSS sensor 22a receives positioning signals transmitted from multiple positioning satellites to acquire the position coordinates of the vehicle M. The road map database 22b is a large-capacity storage medium such as an HDD, and stores road map information. The road map information stored in the road map database 22b includes road information required when executing the driving assistance mode (general roads, main roads, expressways, road shapes, road directions, number of lanes, lane widths, etc.) and static information about parking lots required when executing the parking assistance mode (location information of parking lot entrances and exits, space information within the lot, etc.).

[0022] The driving assistance control unit 11 estimates the vehicle's position (current position) on the road map by map-matching the position coordinates (latitude, longitude, altitude) of the vehicle M acquired by the GNSS sensor 22a onto the road map information stored in the road map database 22b.

[0023] The autonomous driving sensor 23 is a general term for sensors required when driving the host vehicle M autonomously, and is composed of a vehicle speed sensor that detects the vehicle speed (host vehicle speed) of the host vehicle M, a yaw rate sensor that detects the yaw rate acting on the host vehicle M, a longitudinal acceleration sensor that detects longitudinal acceleration, etc.

[0024] The rear sensor 26 is configured by a combination of a monocular camera using a CCD, CMOS, or the like as an imaging element and at least one of an ultrasonic sensor, a millimeter wave radar, a microwave radar, an infrared sensor, a laser radar, a LiDAR (Light Detection and Ranging), etc. Alternatively, the rear sensor 26 may be a stereo camera consisting of a main camera and a sub-camera, similar to the above-mentioned front recognition sensor 21.

[0025] The left and right front side sensors 27 are disposed, for example, on the left and right ridges of the front bumper of the host vehicle M, respectively, and scan a fan-shaped area (scanning area) from the diagonally forward left and right sides of the host vehicle M. On the other hand, the left and right rear side sensors 28 are disposed, for example, on the left and right ridges of the rear bumper, and scan a fan-shaped area from the rear to the left and right of the host vehicle M, which cannot be scanned by the left and right front side sensors 27. Each of these side sensors 27, 28 is made up of a millimeter-wave radar, a microwave radar, a LiDAR, or the like, and receives reflected waves from a target (a parked vehicle Pv, an exterior wall in the parking assist mode) to acquire environmental information such as the distance and direction from the host vehicle M to the target.

[0026] The driving assistance control unit 11 is also connected to an HMI (Human Machine Interface) monitor 31. This HMI monitor 31 displays a mode selection screen that allows the driver to select either a driving assistance mode or a parking assistance mode as an assistance mode to be executed by the driving assistance control unit 11, a parking space selection screen (see FIG. 8) that displays available parking spaces and allows the driver to select one, and the like. Incidentally, this HMI monitor 31 may also serve as a multi-information display of a combination meter or a navigation display device (navigation monitor) of a car navigation system.

[0027] Furthermore, a drive control actuator 32 and an alarm device 33 are connected to the output side of this driving assistance control unit 11. This drive control actuator 32 is a general term for a power actuator, an electric power steering (EPS) actuator, a brake actuator, etc. that assist the driving state of the host vehicle M. Here, the power actuator controls the output of a drive source such as an engine or an electric motor. The EPS actuator controls the drive of the EPS motor. Furthermore, the brake actuator adjusts the brake hydraulic pressure supplied to the brake wheel cylinders provided on each wheel. Furthermore, the alarm device 33 notifies the driver by voice of various information required when each assistance mode is being executed.

[0028] The driving assistance control unit 11 has a parking assistance control function that parks the vehicle M in a parking space on behalf of the driver, or assists the driver when the driver attempts to park the vehicle M in a parking space by driving it himself / herself. The parking assistance control executed by the driving assistance control unit 11 is specifically processed according to a parking assistance control routine shown in Fig. 2. This routine is executed at predetermined calculation intervals after the system is started up.

[0029] In this routine, first, in step S1, the vehicle position information estimated by map locator unit 22 is acquired, and then the routine proceeds to step S2, where map information on the surrounding area of the vehicle position is acquired from map locator unit 22 based on the vehicle position information.

[0030] Next, the process proceeds to step S3, where the vehicle position is mapped on a surrounding map to check whether the vehicle M has entered a parking lot. If it is determined that the vehicle M has entered a parking lot, the process proceeds to step S4. If it is determined that the vehicle M has not entered a parking lot, the process exits the routine.

[0031] When the process proceeds to step S4, an audio announcement is made from the notification device 33 to the driver asking whether or not to set the assistance mode to parking assistance mode, and a parking assistance mode selection screen is displayed on the HMI monitor 31, and the process proceeds to step S5. When the process proceeds to step S5, it is determined whether or not the driver has selected the parking assistance mode, and if the driver has selected the driving assistance mode, the process proceeds to step S6. Furthermore, if the driver does not select the driving assistance mode even after a predetermined time has elapsed after the announcement, or if the driver has selected manual driving on the HMI monitor 31, the process simply exits the routine.

[0032] When the process proceeds to step S6, the parking assistance mode is executed and the routine is exited. The parking assistance mode is executed in accordance with the parking assistance mode execution subroutine shown in Fig. 3. In this subroutine, first, in step S11, forward and forward side environment information recognized by the forward recognition sensor 21, the left and right front side sensors 27, and the left and right front side recognition cameras 29 is acquired.

[0033] Next, the process proceeds to step S12, where vehicles (parked vehicles) Pv parked on the left and right sides of the traffic lane are detected from the acquired front and front-side environmental information. That is, as shown in Fig. 7, while the host vehicle M is traveling at a low speed in the traffic lane, vehicles (parked vehicles) Pv parked side by side on the left and right sides of the traffic lane are detected based on the acquired front and front-side environmental information.

[0034] Then, the process proceeds to step S13, where it is determined whether or not there is a parking space next to the detected parked vehicle Pv. This parking space is a space for normal parking, with a predetermined parking width defined by parking frames (described later), and is a preset fixed value. If no parking space is detected, the process branches to step S14, and if a parking space is detected, the process proceeds to step S15.

[0035] When the process branches to step S14, it is checked whether the parking assistance mode has ended, and if it is determined that the mode has ended, the routine is terminated. On the other hand, if the parking assistance mode is continuing, the process returns to step S11, and the processes of steps S11 to S13 are repeated. The parking assistance mode is terminated by the driver via the HMI monitor 31 or the like. Alternatively, the parking assistance mode is automatically terminated when the driving assistance control unit 11 detects that the host vehicle M has left the parking lot.

[0036] On the other hand, when the process proceeds from step S13 to step S15, it is checked whether a parking frame drawn on the road surface to divide a parking space has been recognized. This parking frame is recognized, for example, based on the front and front side environmental information acquired by the forward recognition sensor 21, the left and right front side sensors 27, and the left and right front side recognition cameras 29, from the brightness difference between the road surface and the edge of the parking frame, or the change in intensity (reflectance) of the reflected light or reflected wave from the road surface and the parking frame.

[0037] If the driving assist control unit 11 determines that a parking space has been recognized, the process proceeds to step S16, where the parking assist process under favorable conditions is executed, and the routine ends. Note that this parking assist process under favorable conditions is the same as the conventional parking assist process in which the host vehicle M is guided to a parking space based on a parking space, and therefore a description thereof will be omitted.

[0038] On the other hand, when it is determined that the parking frame cannot be recognized, that is, the parking frame drawn on the road surface cannot be recognized because the road surface is covered with snow, crown mud remaining after flooding, etc., the process proceeds to step S17, and parking support processing in a bad environment is executed to exit the routine. This parking support processing in a bad environment is executed according to the parking support subroutine in FIGS. 4 to 5.

[0039] In this subroutine, first, in step S21, the virtual parking frame 41 is read. The data of this virtual parking frame 41 is prestored as fixed data in a storage unit such as a ROM or a nonvolatile memory, and it is a frame indicating a criterion for examining whether the host vehicle M can be parked in the parking space when parking the host vehicle M in a bad environment. That is, as shown in FIGS. 6A to 6C, this virtual parking frame 41 is set as a rectangle with four sides orthogonal to each other, the front-rear direction is set to the front-rear length of the host vehicle M, and the left and right have a required parking width Ws obtained by adding a margin width to the vehicle width of the host vehicle M.

[0040] Next, the process proceeds to step S22, and the width (parking space width) Wp of the parking space adjacent to the detected parked vehicle Pv is calculated. This parking space width Wp is based on the front and front-side environment information obtained by the front recognition sensor 21, the left and right front-side sensors 27, and the left and right front-side recognition cameras 29, and recognizes the vehicles (parked vehicles) Pv parked in the parallel direction (see FIGS. 7 and 9) and object targets such as outer walls, and obtains the width of the recognized object targets (parked vehicle Pv, outer wall) and the front distance from the object target to the host vehicle M, and obtains the interval between adjacent object targets (parking space width Wp) from this data. Therefore, the process in this step S22 has a function as the parking interval calculation unit of the present invention.

[0041] Thereafter, the process proceeds to step S23, and the parking space width Wp and the required parking width Ws are compared. When Wp≥Ws, it is determined that the space is sufficient to park the host vehicle M, and the process proceeds to step S24. When Wp<Ws, it is determined that it is difficult to park the host vehicle M, and the process jumps to step S34. Note that the process in this step S23 corresponds to the parking width comparison unit of the present invention.

[0042] In step S24, a virtual parking frame 41 is set in the detected parking space, and the process proceeds to step S25. This virtual parking frame 41 is set such that the widthwise center of the virtual parking frame 41 is set to the widthwise center of the parking space, and the side of the virtual parking frame 41 on the side of the own vehicle M is set to be on the same plane as the front end of the parked vehicle Pv in front (see FIG. 7). The process in step S24 corresponds to the virtual parking frame setting unit of the present invention.

[0043] In this case, for example, as shown in the space on the right side of Fig. 7, if the interval between the parked vehicles Pv is more than twice the required parking width Ws, the number of virtual parking frames 41 that can fit in the space is set at equal intervals in the space. Also, if the interval between the adjacent parked vehicles Pv is wide and three or more virtual parking frames 41 can be set, the parking space is too wide, so the process may jump to step S30 without selecting a virtual parking frame 41.

[0044] In step S25, the number of shoeprints 51 (number of shoeprints) ns within the virtual parking space 41 is counted. The processing in this step corresponds to the shoeprint counting unit of the present invention. Based on the front and front-side environmental information acquired by the forward recognition sensor 21, the left and right front-side sensors 27, and the left and right front-side recognition cameras 29, the shoeprints 51 are recognized by performing well-known pattern matching processing or the like on a series of feature points indicating the outline of the shoeprint from the brightness difference occurring at the step (edge) between the snow-covered surface or the muddy surface originating from the shoeprint 51, or the change in the intensity of the reflected light or reflected wave (reflectance).

[0045] Next, proceed to step S26, and compare the number of shoe prints ns counted within the virtual parking frame 41 with the sidewalk determination threshold nso for determining that the space is a sidewalk. As shown in Figure 10, when the space in which the virtual parking frame 41 is set is a sidewalk, there will be more pedestrian traffic and more scattered shoe prints 51 than when this space is a parking space.

[0046] On the one hand, if this space is a parking space, since the shoe prints 51 are considered to be passengers getting on and off the parked vehicle in the space, as shown in FIG. 11, the shoe prints 51 are detected at biased positions on both sides, so the number of shoe prints ns is considered to be less than that on the sidewalk. The above-described sidewalk determination threshold value nso is a number that can be estimated to have a high possibility of being a sidewalk and is set in advance through experiments or the like. Incidentally, instead of this number of shoe prints ns, the ratio (ns / area) of the number of shoe prints ns to the area of the virtual parking frame 41 may be used. In this case, the sidewalk determination threshold value nso is set to a ratio (for example, about 0.6 to 0.7) for estimating the space as a sidewalk.

[0047] And when ns≥nso, it is determined that the possibility of the space being a sidewalk is high, and the process jumps to step S29. If ns < nso, the process proceeds to step S27. In step S27, it is examined whether the virtual parking frame 41 is a parkable space. That is, if there are object targets (parked vehicle Pv, outer wall) or a large number of shoe prints 51 facing the outer sides of the three sides other than the side facing the own vehicle M side of the virtual parking frame 41, it is estimated that the possibility of the space being a parkable space is high. The parked vehicle Pv and the outer wall, which are object targets, are examined based on the front and front-side environmental information. Also, since the recognition of the shoe prints 51 has been described, the explanation is omitted.

[0048] Incidentally, in the virtual parking frame 41 shown in FIGS. 10 to 16, the side 41a where no object target or shoe print 51 faces is shown by a solid line, and the side  41b where an object target or shoe print 51 faces is shown by a broken line. Also, the processing in steps S25 to S27 corresponds to the parking space determination unit of the present invention.

[0049] Then, if it is determined that the three sides face the landmark or the shoe print 51, the process proceeds to step S28. If it is determined that the side 41a is other than the side 41a on the host vehicle side of the virtual parking frame 41 and that at least one side does not face the landmark or the shoe print 51, the process branches to step S29. For example, as shown in FIG. 11, when three parked vehicles Pv, which are landmarks, face three sides of the virtual parking frame 41, the parking space is surrounded by the parked vehicles Pv, so it can be estimated that the side 41a on the host vehicle side is the entrance / exit of the parking space. Note that the same applies even if the far side or either the left or right side of the virtual parking frame 41 faces the outer wall instead of the parked vehicles Pv.

[0050] 12 and 13, if parked vehicles Pv face two sides other than the side 41a on the host vehicle M side, and multiple shoe prints 51 face the other side, and these shoe prints 51 do not cross the virtual parking frame 41, it can be determined that the pedestrian is intentionally avoiding the virtual parking frame 41, and therefore it can be estimated that the virtual parking frame 41 is highly likely to be a parking space. Note that the shoe prints 51 recognized and counted in FIG. 12 are set within a range extending the required parking width Ws of the virtual parking frame 41.

[0051] Furthermore, as shown in Figure 14, if a parked vehicle Pv faces one side other than the side 41a on the side of the vehicle M, and multiple shoe prints 51 face the other two adjacent sides, and these shoe prints 51 do not cross the virtual parking space 41, as in Figure 13, it can be determined that the pedestrian is intentionally avoiding the virtual parking space 41, and it can be estimated that the virtual parking space 41 is likely to be a parking space.

[0052] On the other hand, as shown in Figures 10, 15, and 16, when there is an edge 41a of the virtual parking frame 41 other than the edge 41a on the vehicle M side that is not faced by a landmark or a shoe print 51, even if no shoe print 51 is detected in the virtual parking frame 41, as shown in Figure 15, for example, it is estimated that no other vehicle has intentionally parked there, and that this space is likely to be a sidewalk. Also, as shown in Figure 16, when an edge 41a that is not faced by a landmark or a shoe print 51 is detected adjacent to the edge 41a on the vehicle M side, it is estimated that there is a high possibility that a sidewalk is set across the adjacent edges 41a, as shown in the same figure.

[0053] Then, in step S27, it is determined that the target object or the shoe print 51 faces the three sides 41b other than the side 41a on the vehicle M side, and the process proceeds to step S28, where the current virtual parking frame 41 is set as an available parking space Ps, and the process proceeds to step S30. Also, when branching to step S29 from either step S26 or S27, the space where the virtual parking frame 41 is set is likely to be a sidewalk, so the virtual parking frame 41 set in the space is cleared, and the process proceeds to step S30. The processing in steps S28 and S29 corresponds to the available parking space setting unit of the present invention.

[0054] When proceeding to step S30 from any of steps S23, S28, and S29, it is checked whether or not detection of all possible parking spaces based on the currently acquired front and front-side environmental information has been completed. If not, the process returns to step S12 in FIG. 3 to search for the next possible parking space and detect the next parked vehicle Pv. If all possible parking spaces have been detected, the process proceeds to step S31.

[0055] In step S31, the currently detected available parking space Ps is displayed on the HMI monitor 31. Fig. 8 shows an example of the available parking space Ps displayed on the HMI monitor 31. As shown by hatching in Fig. 7, when virtual parking frames 41 set in two locations, one on the front side and one on the back side of the traffic lane, are set as available parking spaces Ps, the HMI monitor 31 displays the set available parking spaces Ps in a bird's-eye view.

[0056] Next, the process proceeds to step S32, where the notification device 33 is activated to announce to the driver which of the available parking spaces Ps (two in FIG. 8) displayed on the HMI monitor 31 to select. Then, the process proceeds to step S33, where it is determined whether or not the driver has selected any available parking space. For example, as shown in FIG. 8, if the driver wishes to have the vehicle automatically parked in the available parking space Ps closer to the store, the driver touches the upper available parking space Ps displayed on the HMI monitor 31. The process in step S33 corresponds to the parking space selection unit of the present invention.

[0057] If it is determined in step S33 that the driver has selected one of the available parking spaces Ps, the process proceeds to step S34. If a predetermined time has elapsed since the announcement, or if the vehicle M has passed in front of the available parking space displayed on the HMI monitor 31, the process branches to step S35.

[0058] In step S35, if the driver does not select any parking space after a predetermined time has elapsed, the driving assistance control unit 11 clears all displayed parking spaces, and if the vehicle M passes in front of a corresponding parking space, the display of that parking space is cleared and the process proceeds to step S37.

[0059] In step S37, it is checked whether the parking assist mode has ended, and if it is determined that it has ended, the routine is terminated. On the other hand, if it is determined that the parking assist mode is continuing, the routine returns to step S11 in FIG. 3, and the next parked vehicle Pv is detected based on the newly acquired front and front-side environmental regulations. The parking assist mode is terminated in the same manner as the process in step S14 shown in FIG. 3 described above.

[0060] On the other hand, when the process proceeds from step S33 to step S34, the driving assistance control unit 11 sets the available parking space Ps selected by the driver (upper side in FIG. 8) as the current target parking space Pt, and proceeds to step S36. In step S36, control is executed to automatically park the host vehicle M in the target parking space Pt, and the routine ends. The processing in steps S34 and S36 corresponds to the parking assistance unit of the present invention.

[0061] In the automatic parking control executed by the driving assistance control unit 11 in step S36, first, as shown in FIG. 9, a target parking guidance path Gr for guiding the host vehicle M to the target parking space Pt is set. This target parking guidance path Gr is set so that the center of the host vehicle M in the vehicle width direction coincides with the center of the target parking space Pt in the width direction. Alternatively, for example, if the parking space width Wp between targets (parked vehicles Pv) is greater than or equal to a predetermined value (e.g., 1.5 times) the required parking width Ws of the target parking space Pt for the host vehicle M, the target parking space Pt may be set by shifting the end of the required parking width Ws set on the driver's seat side of the host vehicle M toward the adjacent target (parked vehicle Pv). Then, the target parking guidance path Gr may be set so that the center of the host vehicle M in the width direction is parked at the center of the target parking space Pt in the width direction.

[0062] After that, the driving assistance control unit 11 automatically parks the vehicle M in the target parking space Pt in a predetermined manner, and then exits the routine. Note that this target parking guidance route Gr is set in accordance with the normal target parking guidance route that is set when a parking frame is recognized.

[0063] As a result, for example, as shown in Fig. 9, the position information of all parked vehicles Pv parked in the parking lot can be obtained by having the host vehicle M drive around the traffic lane of the parking lot. In this case, the positions of all parked vehicles Pv parked in the parking lot and the available parking spaces Ps shown by hatching in the figure may be displayed in a bird's-eye view on the HMI monitor 31, as in Fig. 8 described above, so that the driver can select the desired available parking space Ps.

[0064] Thus, when attempting to automatically park the host vehicle in a parking space in a parking lot, if the parking frame that demarcates the parking space is covered by snow, mud, or the like and cannot be recognized, the width Wp of the parking space between adjacent object markers (parked vehicle Pv, wall) is compared with the required parking width Ws of the virtual parking frame 41 set for the host vehicle M. Then, even when Wp ≥ Ws and the number of footprint detections ns detected by the virtual parking frame 41 is less than the sidewalk determination threshold value nso (ns < nso), if there are no object markers or footprints 51 facing any side other than the side 41a on the host vehicle M side, this space is estimated to be highly likely to be a sidewalk. Therefore, it is possible to reduce the inconvenience of guiding the host vehicle M to a sidewalk where parking is prohibited by mistake.

[0065] Note that the present invention is not limited to the above-described embodiment. For example, within the parking lot, the driver manually operates the host vehicle M to drive around and looks for a parking space where the virtual parking frame 41 fits while visually checking the HMI monitor 31. Then, when the driver identifies a parking space where the virtual parking frame 41 fits, the host vehicle M is temporarily stopped before that, and the driving support mode is selected. Thereby, the driving support control unit 11 may check whether the host vehicle M can be parked in the identified parking space and execute driving support when it is determined that parking is possible.

[0066] Also, for example, in the process of step S36 described above, the target parking guidance route Gr may be superimposed and displayed on the HMI monitor 31 for an overhead view of the periphery of the parking space where parking is attempted, and the driver may park the host vehicle M along the target parking guidance route Gr by their own driving.

Explanation of Reference Numerals

[0067] 1... Parking support device, 11... Driving support control unit, 21... Forward recognition sensor, 21a... Main camera, 21b... Sub camera, 21c... Image processing unit (IPU), 22... Map locator unit, 22a... GNSS sensor, 22b...Road map database, 23...Autonomous driving sensor, 24...Brake sensor, 25...Select position sensor, 26...rear sensor, 27...Left and right front side sensors, 28...Right and left rear side sensors, 29...Left and right front side recognition cameras, 31...HMI monitor, 32...Drive control actuator, 33...alarm device, 41...Virtual parking space, 41a...the side that does not face landmarks or footprints, 41b...the area facing the landmarks and footprints, 51...shoe prints, Gr...target parking guidance route, M...own vehicle, Ps... Parking space available, Pt...target parking space, Pv...parked vehicles, Wp...parking space width, Ws: Required parking width, ns...number of shoe prints, nso…sidewalk detection threshold

Claims

1. A parking assistance device that guides a vehicle to an available parking space in a parking lot, an environmental information acquisition unit that acquires environmental information around the host vehicle; a storage unit that stores a virtual parking space required for parking the vehicle; a parking space calculation unit that calculates the width of a parking space between targets based on the environmental information acquired by the environmental information acquisition unit; a parking width comparison unit that compares the width of the parking space calculated by the parking interval calculation unit with the width of the virtual parking frame stored in the storage unit; a virtual parking frame setting unit that sets the virtual parking frame within the parking space when the parking width comparison unit determines that the width of the parking space is wider than the width of the virtual parking frame; a parking space determination unit that determines whether the target or shoe print recognized based on the environmental information acquired by the environmental information acquisition unit faces the outside of all sides of the virtual parking frame set by the virtual parking frame setting unit except for the side on the vehicle side; a parking space setting unit that sets the virtual parking frame as the parking space when the parking space determination unit determines that the target or the shoe print faces the outside of all sides of the virtual parking frame set by the virtual parking frame setting unit except for the side on the vehicle side; a parking assistance unit that guides the vehicle to the available parking space set by the available parking space setting unit; A parking assistance device comprising:

2. The parking space determination unit clears the virtual parking space when the number of shoe prints in the virtual parking space exceeds a sidewalk determination threshold.

2. The parking assistance device according to claim 1.

3. The parking space determination unit clears the virtual parking frame when the target or the shoe print does not face the outside of at least one side of the virtual parking frame excluding the side on the host vehicle side.

2. The parking assistance device according to claim 1.

4. The side of the virtual parking frame that does not face the target is the side of the host vehicle and the side facing the side of the host vehicle, or the side of the host vehicle and the side adjacent to the side of the host vehicle.

4. The parking assistance device according to claim 3.

5. The vehicle further includes a parking space selection unit that allows a driver to select one of the available parking spaces when the available parking space setting unit sets a plurality of available parking spaces, The parking assistance unit guides the vehicle to the available parking space selected by the parking space selection unit.

5. The parking assistance device according to claim 1, wherein the parking assistance device is a parking assistance device.

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