Parking assistance system and parking assistance method

Abstract

This allows the driver to complete parking as intended without any discomfort. [Solution] The parking assistance system can be mounted on a vehicle and comprises a parking position selection unit that extracts parking position candidates, which are candidates for positions where the vehicle is to be parked; a standard trajectory generation unit that generates a standard trajectory to the parking position candidate; an operation assistance amount determination unit that calculates an operation assistance amount by multiplying a gain by the deviation, which is the deviation of the vehicle's state from the standard trajectory; and a vehicle control assistance unit that assists the driver in parking operations based on the operation assistance amount, and the operation assistance amount determination unit increases the gain according to the progress of the parking operation.

Description

[Technical Field]

[0001] The present invention relates to a parking assistance system and a parking assistance method. [Background technology]

[0002] In recent years, computer-based vehicle driving assistance functions have been developed. Driving assistance is being developed not only for driving on roadways but also for parking. Patent Document 1 discloses a parking assistance device that assists parking, characterized in that it performs parking assistance based on direction information related to the direction of the driver's face and / or line of sight. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-253819 Summary of the Invention [Problem to be solved by the invention]

[0004] The invention described in Patent Document 1 does not allow parking to be performed in accordance with the driver's intentions. [Means for solving the problem]

[0005] A parking assistance device according to a first aspect of the present invention includes a parking position candidate extraction unit that extracts parking position candidates that are candidates for positions at which a vehicle is parked, a standard trajectory generation unit that generates a standard trajectory to the parking position candidate, a vehicle control assistance unit that performs vehicle control to assist a driver in parking a vehicle based on the standard trajectory, and a vehicle control assistance level determination unit that determines a vehicle control assistance level that is the degree of vehicle control assistance provided by the vehicle control assistance unit, and the vehicle control assistance level determination unit increases the vehicle control assistance level according to the progress of the parking operation. A parking assistance method according to a second aspect of the present invention is a parking assistance method executed by one or more computers, and includes: a parking position candidate extraction step of extracting parking position candidates that are candidates for positions at which to park a vehicle; a normative trajectory generation step of generating a normative trajectory to the parking position candidate; a vehicle control assistance step of performing vehicle control to assist the driver in a parking operation based on the normative trajectory; and a vehicle control assistance level determination step of determining a vehicle control assistance level that is a degree of vehicle control assistance in the vehicle control assistance step, wherein the vehicle control assistance level is increased depending on the progress of the parking operation in the vehicle control assistance level determination step. [Effects of the Invention]

[0006] According to the present invention, the driver can complete parking as intended without feeling any discomfort. [Brief explanation of the drawings]

[0007] [Figure 1] Diagram of a vehicle equipped with a parking assistance system [Figure 2] Parking assistance system hardware configuration diagram [Figure 3] Parking assistance system configuration diagram [Figure 4] FIG. 1 is a diagram illustrating parking in the first embodiment. [Figure 5] FIG. 10 is a diagram showing changes in the steering angle and the like in the first embodiment. [Figure 6] FIG. 10 is a diagram showing the relationship between deviation and intermediate variables in Modification 1. [Figure 7] FIG. 10 is a diagram illustrating calculation of the amount of assistance using a gaze point in the direction of travel in Modification 4. [Figure 8] FIG. 10 shows changes in the steering angle and the like in Modification 4. [Figure 9] FIG. 20 shows changes in speed and gain in Modification 6. [Figure 10] System configuration diagram of a parking assistance device according to a second embodiment [Figure 11] FIG. 10 is a diagram showing changes in the steering angle and the like in the second embodiment. [Figure 12]FIG. 10 is a diagram illustrating parking in the third embodiment. [Figure 13] FIG. 11 is a diagram showing a movement path generated by a reference trajectory generating unit in the third embodiment. [Figure 14] A diagram showing the reference trajectory and the vehicle's trajectory when the driver parks facing forward in the second parking space. [Figure 15] FIG. 10 is a diagram showing changes in the steering angle and the like in the third embodiment. [Figure 16] System configuration diagram of a parking assistance device according to a fourth embodiment [Figure 17] Configuration diagram of a parking assistance system that also utilizes hardware devices outside the vehicle DETAILED DESCRIPTION OF THE INVENTION

[0008] -First embodiment- A first embodiment of a parking assistance system and a parking assistance method will be described below with reference to FIGS.

[0009] (Vehicle configuration) 1 is a configuration diagram of a vehicle 1 equipped with a parking assistance device 10. The vehicle 1 includes wheels, a steering input device 100, a steering actuator device 200, a steer-by-wire system in which the steering input device 100 and the steering actuator device 200 are mechanically separated, a plurality of external sensors for acquiring external data, an engine or a motor for driving the front and rear wheels, and a brake. The wheels are a collective term for a left front wheel 22FL, a right front wheel 22FR, a left front wheel 22RL, and a right rear wheel 22RR.

[0010] The external sensors include a rear camera 301, a side camera 302, a first front camera 304, and a second front camera 305. However, the external sensors may also include a laser distance meter, a laser range finder, and a receiver for using a satellite navigation system. The position of the vehicle 1 can be calculated using data received by this receiver from multiple satellites. Hereinafter, the data acquired by the external sensors will be referred to as "external sensor signals."

[0011] The steering input device 100 includes a steering shaft 101, a steering reaction force actuator 102, a steering amount sensor 103, and a steering wheel 115. The steering reaction force actuator 102 includes a device that applies a steering load (steering reaction force) to the steering shaft 101 and the steering wheel 115 using a reaction force motor. The steering actuator device 200 includes a steering actuator 201 that applies a steering force to the left front wheel 22FL and right front wheel 22FR, which are steered wheels, and a steering motor 202 that generates the steering force.

[0012] Vehicle 1 further includes accelerator pedal 111, an accelerator operation amount sensor that detects the stroke when the driver depresses accelerator pedal 111, brake pedal 112, a brake operation amount sensor that detects the amount of depression of the brake pedal by the driver, and a steering operation amount sensor that detects the amount of operation of steering wheel 115 by the driver. Hereinafter, data acquired by steering amount sensor 103, steering operation amount sensor, accelerator operation amount sensor, brake operation amount sensor, etc. will be referred to as "operation amount data."

[0013] The vehicle 1 further includes an integrated controller 2 that calculates the required steering force, steering reaction force, braking force, driving force, etc. using the operation amount signal, external sensor signals, and, if necessary, map data, etc., and issues necessary commands to the engine, motor, brake, steering actuator, reaction motor, etc. The integrated controller 2 includes an external world data controller 3 and a parking assistance device 10. Note that, although the external world data controller 3 and the parking assistance device 10 are described here as separate devices, some or all of the functions of the external world data controller 3 may be included in the parking assistance device 10.

[0014] The integrated controller 2 may be configured to perform all calculations in one unit, or the calculations may be shared among multiple units. When multiple integrated controllers 2 are used, a lower-level controller may be provided for each actuator, with commands being given from the upper-level controller to the lower-level controllers. An external data controller 3 is also provided to acquire and analyze information from external sensors, and is configured as part of the integrated controller 2. Each controller is centered around an electronic control unit that includes a memory area for storing various programs and data, and a CPU that performs processing based on that information.

[0015] The external data controller 3 receives external sensor signals as input and outputs organized surroundings data indicating the locations of obstacles, parking spaces, parking lot sections, etc. The organized surroundings data is essentially a dimensional map of the surroundings. Note that input to the external data controller 3 may include map data stored outside or inside the vehicle 1, data related to the parking lot, data on parked vehicles, etc. The map data is, for example, an existing database of obstacle positions. By obtaining the position and orientation of the vehicle 1 from the external sensor signals, the external data controller 3 can indirectly obtain the positions of surrounding obstacles using the map data. The data related to the parking lot includes, for example, the latitude and longitude of the parking lot and data on divisions such as white lines within the parking lot. The parked vehicle data is data indicating the positions and sizes of parked vehicles around the vehicle 1.

[0016] The external data controller 3 generates the periphery organized data using the camera images and laser range finder output included in the external sensor signal, for example, as follows: The external data controller 3 previously stores the positions and orientations of each camera mounted on the vehicle 1 as well as the camera's internal parameters. The external data controller 3 then calculates the relative position of the subject included in the captured image and the vehicle 1, assuming that the vehicle 1 is on flat ground. The external data controller 3 also extracts white lines and obstacles from the captured image and accumulates position data of the white lines and obstacles based on the position and orientation of the vehicle 1 and the positions and orientations of the cameras fixed to the vehicle 1. If the external sensor signal includes laser range finder output, this output indicates the relative position of the obstacle and the vehicle 1. Therefore, the external data controller 3 accumulates obstacle position data based on the position and orientation of the vehicle 1 and the position and orientation of the laser range finder fixed to the vehicle 1. The external data controller 3 outputs this accumulated white line and obstacle data as periphery organized data.

[0017] The integrated controller 2 generates vehicle state data 822 (described later) using the external sensor signals and outputs it to the parking assistance device 10. The vehicle state data 822 includes the current vehicle speed, front wheel steering angle, rear wheel steering angle, vehicle position, vehicle orientation, etc. However, if the external sensor signals contain the vehicle state data 822 as is, the integrated controller 2 does not need to perform any special calculations.

[0018] (Hardware configuration) 2 is a hardware configuration diagram of the parking assistance device 10. The parking assistance device 10 includes a CPU 401, which is a central processing unit, a ROM 402, which is a read-only storage device, a RAM 403, which is a readable and writable storage device, an input / output device 404, which is a user interface, and a communication device 405. The CPU 401 loads a program stored in the ROM 402 into the RAM 403 and executes it to perform the various calculations described above. The parking assistance device 10 may be realized by an FPGA (Field Programmable Gate Array), which is a rewritable logic circuit, or an ASIC (Application Specific Integrated Circuit), which is an application-specific integrated circuit, instead of the combination of the CPU 401, the ROM 402, and the RAM 403.

[0019] Furthermore, instead of the combination of the CPU 401, ROM 402, and RAM 403, the parking assistance device 10 may be realized by a combination of different configurations, for example, a combination of the CPU 401, ROM 402, RAM 403, and an FPGA. The communication device 405 enables communication between the parking assistance device 10 and devices inside and outside the vehicle 1. The communication device 405 is, for example, a communication module. For convenience, FIG. 2 illustrates the parking assistance device 10 as being composed of a single hardware device, but the parking assistance device 10 may also be composed of multiple hardware devices. In this case, the hardware devices may be installed adjacent to each other or may be connected via a local area network or the Internet. Therefore, the parking assistance device 10 may also be called a "vehicle assistance system" composed of one or more computers.

[0020] (System Configuration) 3 is a system configuration diagram of parking assistance device 10. Parking assistance device 10 includes parking position selection unit 11, reference trajectory generation unit 12, operation assistance content determination unit 14, vehicle control assistance unit 15 that assists the operation of vehicle 1, and start determination unit 19 that determines the start of assistance. Surroundings organized data 821, vehicle state data 822, and operation amount data 823 are input to parking assistance device 10. Operation assistance content determination unit 14 outputs operation assistance amount 827 to vehicle control assistance unit 15.

[0021] The parking position selection unit 11 uses the surroundings organized data 821 and the vehicle state data 822 to calculate possible parking position and orientation in the parking lot as parking position candidate 825. Since the calculation of parking position candidate by the parking position selection unit 11 can also be referred to as "selection" or "extraction," the parking position selection unit 11 can also be called a "parking position candidate extraction unit." In this embodiment, only one parking position candidate 825 is calculated. Note that, since obstacles may move, the calculation of the parking position candidate 825 by the parking position selection unit 11 may be updated as needed.

[0022] For example, the parking position selection unit 11 calculates the parking position candidate 825 as follows: First, the parking position selection unit 11 selects a candidate parking position for the vehicle 1 using the surroundings organized data 821. This selection may be performed on the condition that there is a space that is the size of the vehicle 1 plus a predetermined margin. The size of the vehicle 1 is stored in advance in the ROM 402, for example. Next, the parking position selection unit 11 eliminates candidate parking positions that are not reachable from the selected candidate parking positions based on the vehicle state data 822.

[0023] For example, candidate stopping positions that are surrounded by obstacles or candidate stopping positions that will come into contact with obstacles before reaching the candidate stopping position due to limitations on the turning radius of the vehicle 1 are eliminated. Furthermore, the parking position selection unit 11 sets the orientation of the vehicle 1 with respect to the remaining candidate stopping positions, and sets the combination of the position and orientation as candidate parking position 825. For example, if the candidate stopping position is rectangular, two orientations that are 180 degrees apart can be set so that the longitudinal direction of the vehicle 1 and the longitudinal direction of the candidate stopping position coincide with each other.

[0024] For example, when there are multiple candidate stopping positions and orientations, the parking position selection unit 11 determines only one candidate parking position 825 using some kind of criterion. This criterion may be, for example, the minimum amount of movement of the vehicle 1, the minimum amount of steering of the vehicle 1, or the maximum distance to the nearest obstacle. The parking position selection unit 11 selects only one orientation from two orientations that differ by 180 degrees, for example, by the following procedure. That is, the parking position selection unit 11 calculates the route of the vehicle 1 from the current position of the vehicle 1 to the two orientations of the candidate stopping positions, and determines the combination of the orientation and candidate stopping position with the shorter route as the candidate parking position 825.

[0025] The reference trajectory generating unit 12 uses the surroundings organized data 821, the vehicle state data 822, the operation amount data 823, and the parking position candidate 825 to calculate a trajectory from the current position to the parking position candidate 825 as a reference trajectory 826. The reference trajectory generating unit 12 calculates the reference trajectory 826 using various known methods. The reference trajectory 826 includes at least one of a movement path, a steering angle, a speed, a shift state (forward, reverse), a vehicle yaw angle, and the like.

[0026] Hereinafter, the movement path, steering angle, and speed as the standard trajectory 826 will be referred to as the "standard trajectory," "standard steering angle," and "standard speed," respectively. An example of the case where the standard trajectory generation unit 12 calculates the standard trajectory will be described later. Also, below, a "driver trajectory" will be defined as a concept corresponding to the standard trajectory 826. The driver trajectory is the trajectory of the vehicle 1 that has actually moved due to the driver's operation, and includes at least one of the movement path, steering angle, speed, shift state (forward, reverse), vehicle yaw angle, etc.

[0027] The operation assistance content determination unit 14 calculates an operation assistance amount 827 based on the operation amount data 823 and the reference trajectory 826 so that the movement of the vehicle 1 coincides with the reference trajectory 826. The operation assistance amount 827 is a combination of the identifier and operation amount of the actuator to be assisted. The operation amount tends to increase according to the progress of the parking operation, as will be described later. However, if there is only one actuator to be assisted, the operation assistance amount 827 may be just the operation amount. In the following, to simplify the explanation, the case where there is one actuator to be assisted will be mainly discussed, and the identifier of the actuator will not be explained. The actuator to be assisted is the steering reaction force actuator 102 or the steering actuator 201.

[0028] The operation assistance content determination unit 14 includes an assistance level determination unit 14-1 and an assistance amount determination unit 14-2. The assistance level determination unit 14-1 determines a vehicle control assistance level that increases according to the progress of the parking operation. However, hereinafter, the vehicle control assistance level will also be referred to as the "assistance level." The assistance amount determination unit 14-2 calculates a deviation, which is a deviation of the state of the vehicle 1 from the reference trajectory 826, and calculates an assistance amount by multiplying the deviation by the assistance level determined by the assistance level determination unit 14-1 as a gain 64. Note that hereinafter, the assistance level will also be referred to as the "vehicle operation assistance level," and the assistance amount will also be referred to as the "operation assistance amount." The assistance amount determination unit 14-2 determines the assistance amount for assisting in the control of the vehicle 1, and therefore can also be referred to as the "vehicle control assistance amount determination unit."

[0029] The progress of the parking operation is defined as a function of the distance between the vehicle 1 and the parking position candidate 825, and it is determined that the closer the vehicle 1 is to the parking position candidate 825, the closer the parking operation is to completion. This distance may be a straight-line distance or a distance along the reference trajectory 826. For example, the assistance level determination unit 14-1 sets the assistance level corresponding to the distance between the vehicle 1 and the parking position candidate 825 when the parking assistance device 10 starts assisting the parking operation to zero, and sets the assistance level corresponding to the distance between the vehicle 1 and the parking position candidate 825 being zero to the maximum value. As described above, the assistance amount determination unit 14-2 calculates the operation assistance amount by multiplying the deviation by the gain. Therefore, when the parking assistance device 10 starts assisting the parking operation, the gain 64 is zero, so the operation assistance amount is zero regardless of the magnitude of the deviation.

[0030] Vehicle control assist unit 15 operates actuators and the like based on operation assist amount 827. The background behind the ability of vehicle control assist unit 15 to assist operation will be described. The operation of a typical steer-by-wire steering system is as follows. First, the driver operates steering wheel 115, and the rotation angle of steering shaft 101 (steering wheel angle) is detected by steering amount sensor 103. Steering actuator device 200 then controls steering actuator 201 in accordance with the output of steering amount sensor 103. That is, the position of steering actuator 201 is determined in accordance with the steering wheel angle, and further the front wheel steering angle is determined, so that the steering wheel steering angle and the front wheel steering angle correspond to each other. However, in a steer-by-wire steering system, the steering wheel and the front wheels are not mechanically connected, so operation assistance is possible based on operation assist amount 827 calculated by operation assistance content determination unit 14. However, the configuration described in this embodiment can also be applied to a so-called mechanical link in which the steering wheel and the wheels are mechanically connected. The vehicle control assistance unit 15 can also be called a "vehicle control assistance unit" because it assists the driver in controlling the vehicle 1.

[0031] The start determination unit 19 determines whether parking assistance for the vehicle 1 by the parking assistance device 10 is necessary, and if it determines that assistance is necessary, it operates the parking position selection unit 11, the reference trajectory generation unit 12, the operation assistance content determination unit 14, and the vehicle control assistance unit 15. The start determination unit 19 compares the position of the vehicle 1 with map data, and if the vehicle 1 is near the entrance to the parking lot 30 or if the vehicle 1 is in the parking lot 30, it infers the driver's intention to enter the parking lot and starts parking assistance. However, if the vehicle 1 is near the entrance to the parking lot 30, an additional condition for starting parking assistance may be that the vehicle 1 is heading toward the parking lot. The start determination unit 19 may also start parking assistance if the vehicle 1 has arrived near a destination set in a navigation system installed in the vehicle 1, or if it recognizes words such as "parking" or "stop the car" through voice recognition of the driver's speech.

[0032] (Example of operation) FIG. 4 is a top view of a parking lot 30 in which a vehicle 1 is parked. With reference to FIG. 4, the operation of parking the vehicle 1 backward into one of the parking spaces will be described. The parking lot 30 has an upper boundary line 31 and a lower boundary line 32 that are parallel to each other at the top and bottom ends of the illustration. The parking lot 30 has multiple white lines that intersect perpendicularly with the lower boundary line 32, and these white lines indicate parking spaces for four vehicles. These four parking spaces are occupied by other vehicles except for the second space 40 from the left.

[0033] Section 40 is a parking area surrounded by first white line 40a and second white line 40b. Vehicle 1 is attempting to park backwards in section 40. In Figure 4, a dashed line passing through the center axis of vehicle 1 and a reference line 52, which is a dashed line passing through the center of gravity of vehicle 1 and parallel to upper boundary line 31 and lower boundary line 32, are shown for ease of explanation.

[0034] First, when the driver drives the vehicle 1 toward the entrance of the parking lot, the start determination unit 19 determines that parking assistance is necessary through the above-described process. Then, the parking position selection unit 11, the reference trajectory generation unit 12, the operation assistance content determination unit 14, and the vehicle control assistance unit 15 start operating. After that, the driver operates the vehicle so that the center of gravity is stopped in front of the second section from the right, with the vehicle slightly turned left with respect to the reference line 52. At this time, the parking position selection unit 11 selects section 40 as an available parking area based on external data from a camera or the like as a parking space. Furthermore, based on the current orientation of the vehicle 1, the parking position selection unit 11 determines that the parking orientation should be backward. That is, the parking position selection unit 11 calculates the combination of an orientation in which the upper side of the figure is the front of the vehicle 1 and section 40 as the parking position candidate 825.

[0035] The reference trajectory generating unit 12 calculates, as the reference trajectory 51, a movement path from the initial position A1, which is the current position of the center of gravity of the vehicle 1, to the final stop position Aend, which is the position of the center of gravity of the vehicle 1 in the parking position candidate 825. The reference trajectory 51 is included in the reference trajectory 826. For example, it is preferable that the center of gravity of the final stop position Aend coincides with the center of the first white line 40a and the second white line 40b. The center of the first white line 40a and the second white line 40b is a position midway between the center of the first white line 40a and the center of the second white line 40b. Furthermore, it is preferable that the orientation of the vehicle 1 in the parking position candidate 825 is such that the center line of the vehicle 1 is parallel to the first white line 40a and the second white line 40b. Here, the position of the center of gravity of the vehicle 1 is used to set the path, but it may also be the center of the front or rear wheel axle, for example.

[0036] An example of a method for calculating a reference path by the reference trajectory generating unit 12 will be described. The reference trajectory generating unit 12 connects the initial position A1 to the final stop position Aend using straight lines, arcs, and a combination of straight lines. The lines and arcs are connected using transition curves or the like. The radius of the arc portion is set to be larger than the minimum radius of the vehicle 1 so that the reference path can be corrected later. The angle of the start position of the arc portion is determined so that it matches the yaw angle (θA1), which is the angle between the reference line 52 and the initial position A1. The reference trajectory generating unit 12 can calculate the reference path by adjusting the length from the start position to the start position of the arc and the length of the straight line portion from the end of the arc toward the stop position. This allows the reference trajectory generating unit 12 to create a reference path 51 as shown by the solid line in FIG. 4. Once the reference path 51 is calculated, a reference steering angle, which is the front wheel steering angle that serves as a reference for moving the vehicle 1 along the reference path 51, is also determined.

[0037] Then, the operation assistance content determination unit 14 calculates an operation assistance amount 827 so that the vehicle 1 follows the calculated reference path. If the identifier included in the operation assistance amount 827 is the steering actuator 201, the vehicle control assistance unit 15 outputs a correction command to the steering actuator 201. Therefore, the steering actuator 201 generates torque due to both the steering operation by the driver and the correction command from the vehicle control assistance unit 15. Note that in FIG. 4, the reference path 51 is depicted as a thin line for convenience of drawing. However, the reference path 51 may have a width. In this case, even if the position of the vehicle 1 does not coincide with the center of the reference path 51, the deviation may be set to zero as long as it is within the range of the aforementioned width.

[0038] FIG. 5 shows changes in the steering angle, etc. From the top of FIG. 5, the changes in the front wheel steering angle, gain, and steering angle correction amount are shown. The horizontal axis of FIG. 5 represents the movement amount of the vehicle 1, which is synchronized with the vertical direction. The dashed line on the left of FIG. 5 indicates the initial position A1, and the dashed line on the right indicates the final stopping position Aend. Regarding the steering angles shown in the upper part of FIG. 5, the solid line indicates the reference steering angle 61, the thin dashed line indicates the steering angle based on the user operation (hereinafter referred to as the "user-operated steering angle") 62, and the thick dashed line indicates the steering angle when assistance is provided by the vehicle control assistance unit 15 (hereinafter referred to as the "assisted post-steering angle") 63. In other words, the steering angle when no special processing is performed is indicated by reference symbol 62, and changes to the steering angle indicated by reference symbol 63 when assistance based on the operation assistance amount 827 is added. The reference steering angle 61 indicates that the steering wheel 115 is first turned to the right, then maintained at a constant angle, and then returned to the straight ahead direction.

[0039] In this example, since the start of steering by the driver is delayed, a deviation is detected between the user-operated steering angle 62 and the standard steering angle 61. Here, this deviation is multiplied by a gain 64, and position control is performed using the steering actuator 201 so that the steering angle follows the standard steering angle 61. This gain 64 is a function of the distance from the final stopping position Aend. The gain 64 is set so that it gradually increases from the initial position A1 of the parking assistance and becomes larger as it approaches the final stopping position Aend. As a result, the assist rear steering angle 63 passes between the user-operated steering angle 62 and the standard steering angle 61 and gradually approaches the standard steering angle 61.

[0040] The operation of the vehicle 1 at this time will be described with reference to Figure 4 again. In Figure 4, the solid line indicates the reference path 51, the thin dashed line indicates the user operation path 53 based on the driver's operation, and the thick dashed line indicates the assisted path 54 based on the assistance provided by the vehicle control assistance unit 15. The user operation path 53 stops the vehicle to the left of the center of the parking stall due to a delay in the start of steering. In contrast, the assisted path 54 is located closer to the center of the section 40 than the user operation path 53, and is stopped at a more appropriate position. At this time, the amount of assistance gradually increases, so the driver can complete the parking operation by operating the steering wheel as usual without feeling any discomfort.

[0041] According to the first embodiment described above, the following advantageous effects can be obtained. (1) The parking assistance device 10 includes a parking position candidate extraction unit (i.e., parking position selection unit 11) that extracts a parking position candidate 825, which is a candidate for a position where the vehicle 1 is to be parked; a standard trajectory generation unit 12 that generates a standard trajectory 826 to the parking position candidate 825; a vehicle control assistance unit 15 that performs vehicle control to assist the driver in parking the vehicle based on the standard trajectory 826; and a vehicle control assistance level determination unit (i.e., assistance level determination unit 14-1) that determines the assistance level, which is the degree of vehicle control assistance provided by the vehicle control assistance unit 15. The assistance level determination unit 14-1 increases the assistance level according to the progress of the parking operation of the vehicle 1. This allows the driver to complete parking according to his or her intentions without feeling any discomfort. In reality, the parking assistance device 10 assists the operation of the vehicle 1, but the driver does not feel any discomfort, especially at the start of assistance, because the gain 64 is small, and the driver can feel satisfied that he or she has successfully completed parking by driving alone.

[0042] (2) The parking assistance device 10 includes a vehicle control assistance amount determination unit that calculates an operation assistance amount by multiplying the deviation, which is the deviation of the state of the vehicle 1 from the reference trajectory 826, by the assistance degree as a gain. The vehicle control assistance unit 15 assists the driver in parking the vehicle based on the operation assistance amount.

[0043] (3) The vehicle control assistance unit 15 starts vehicle control assistance when the parking position candidate 825 is extracted by the parking position selection unit 11. Therefore, parking assistance can be provided from an early stage after the driver starts parking.

[0044] (4) The parking position candidates also include limitations on the direction in which the vehicle 1 is parked.

[0045] (5) The operation assistance content determination unit 14 calculates the assistance amount for the steering amount.

[0046] (6) The progress status is the distance traveled from the current position of the vehicle 1 to the parking position candidate 825. The shorter the distance from the current position of the vehicle 1 to the parking position candidate 825, the higher the operation assistance content determination unit 14 increases the gain 64. Therefore, the closer the vehicle 1 gets to the parking position candidate 825, the higher the gain 64 becomes, allowing the driver to complete parking as intended without feeling any discomfort.

[0047] (7) The reference trajectory generating unit 12 generates at least one of the reference path, steering angle, and acceleration / deceleration as the reference trajectory 826.

[0048] (8) The operation assistance content determination unit 14 continuously changes the gain 64. Therefore, a sudden change in the amount of assistance caused by a sudden change in the gain 64 does not occur, and the driver does not feel uncomfortable.

[0049] (Variation 1) In the first embodiment described above, the amount of assistance is calculated by calculating the product of the deviation between the reference steering angle 61 and the user-operated steering angle 62 and the gain 64. However, an intermediate variable may be provided for the deviation, and the product of the intermediate variable and the gain 64 may be calculated. The relationship between the deviation and the intermediate variable may be proportional, or may be in a form other than proportional.

[0050] FIG. 6 is a diagram showing the relationship between the deviation and the intermediate variable in Modification 1. As shown in FIG. 6(a), when the absolute value of the deviation is smaller than a predetermined threshold, the intermediate variable may be set to zero. Also, as shown in FIG. 6(b), when the absolute value of the deviation is within a range smaller than a predetermined threshold, the rate of increase in the intermediate variable relative to an increase in the deviation may be reduced. In this modification, when the deviation is within a predetermined absolute value range, no unnecessary intervention is performed, and assistance is not provided to skilled drivers, thereby realizing parking assistance that feels natural.

[0051] (Variation 2) In the first embodiment described above, the amount of assistance is calculated by calculating the product of the gain 64 and the deviation between the reference steering angle 61 and the user-operated steering angle 62. However, instead of using the deviation itself, it is also possible to use the derivative of the deviation, the integral of the deviation, or a combination of the derivative of the deviation and the integral of the deviation. This makes it possible to provide assistance with high accuracy.

[0052] (Variation 3) The standard trajectory generating unit 12 may not only generate the standard trajectory 826 when parking assistance is started, but may also regenerate the standard trajectory 826 from time to time or at appropriate timings as the vehicle 1 moves thereafter. The standard trajectory 826 may be regenerated, for example, every time the vehicle 1 travels a predetermined distance, or every time a predetermined time has passed. It may also be regenerated when the difference between the standard trajectory 826 and the vehicle's trajectory is equal to or greater than a predetermined value. By regenerating the standard trajectory 826, the vehicle operates along the optimal trajectory at the time of regeneration, making it possible to stop the vehicle at a more ideal parking position.

[0053] (Variation 4) In the first embodiment described above, the amount of assistance is determined based on the deviation between the standard steering angle 61 and the user-operated steering angle 62. However, the amount of assistance may be calculated by referring to a traveling direction gaze point set on the standard route.

[0054] 7 and 8 are diagrams showing a top view of the parking lot 30 and changes in the steering angle, etc., when the amount of assistance is calculated using the traveling direction gaze point. In this modified example, the operation assistance content determination unit 14 first sets a traveling direction gaze point 72 on the central axis of the vehicle 1, indicated by the dashed dotted line, and a predetermined distance in the traveling direction from the center of gravity of the vehicle 1. Next, the operation assistance content determination unit 14 identifies a route point 71, which is the point on the reference route 51 that is closest to the traveling direction gaze point 72. The operation assistance content determination unit 14 then calculates the angle between the line segment connecting the route point 71 and the center of gravity of the vehicle 1 and the reference line 52 as the route point angle 71P, and the angle between the central axis of the vehicle 1 and the reference line 52 as the gaze point angle 72P.

[0055] Furthermore, the operation assistance content determination unit 14 determines the deviation between the path point angle 71P and the gaze point angle 72P as a yaw angle deviation, and multiplies this yaw angle deviation by the gain described above to calculate and add a steering angle correction amount. As in the first embodiment, this gain is set to 0 at the start and to increase as the vehicle approaches the final parking position. This gradually increases the steering angle correction amount without increasing abruptly, so that the vehicle movement is corrected with little discomfort to the driver, and the vehicle can ultimately be parked in the ideal position.

[0056] (Variation 5) In the first embodiment described above, parking of the vehicle 1 in a parking lot 30 has been described. However, assistance by the parking assistance device 10 is not limited to parking lots, and may be applied to other parking styles such as parallel parking and parking in a garage. In this case, the parking assistance device 10 starts parking assistance when, for example, the speed of the vehicle 1 is equal to or less than a predetermined value and the parking position selection unit 11 is able to calculate a parking position candidate 825. However, an additional condition for starting parking assistance may be that the vehicle is not in an area where parking is prohibited, based on map data or external sensor signals.

[0057] (Variation 6) In the first embodiment described above, a standard path, a standard steering angle, and a standard speed are shown as specific examples of the standard trajectory 826. However, the standard trajectory 826 may be a combination of two or more of the above three. Here, a case where the standard trajectory 826 is a combination of the standard path and the standard speed will be described using an example of parking backward, as in FIG. 4.

[0058] Fig. 9 is a diagram showing changes in speed and gain in Modification 6. The reference trajectory generating unit 12 in this modification also calculates a reference speed 141. The speeds shown in the upper part of Fig. 9 are the reference speed 141 calculated by the reference trajectory generating unit 12, a user operation speed 142 based on the driver's operation, and a post-assistance speed 143 which is the speed when assistance is provided by the vehicle control assistance unit 15. The reference speed 141 is set so that the vehicle stops after acceleration, a constant speed, and deceleration, and so that the acceleration and constant speed, or the constant speed to deceleration, acceleration, and deceleration are within a predetermined range, and so that the change in acceleration does not become abrupt when the vehicle changes from deceleration to a stop.

[0059] As in the first embodiment, gain 64 increases as parking of vehicle 1 progresses. A value obtained by multiplying the deviation between reference speed 141 and user-operated speed 142 by gain 64 is calculated as operation assistance amount 827 for correcting the speed. Acceleration and deceleration based on this operation assistance amount are performed by the engine, motor, brake, etc., and the speed of vehicle 1 becomes post-assistance speed 143. In the example shown in FIG. 9, the speed at a constant speed of user-operated speed 142 is faster than the reference speed, and the timing of deceleration when stopping is late. If the driver's operation is left as is, the vehicle will stop with a large deceleration, but correction will make it possible to stop with an appropriate deceleration. Although an example of late deceleration timing has been shown, if the driver's operation is such that the deceleration timing is too early, there is a possibility that the vehicle will stop too far forward in the parking position. Therefore, a correction is made to reduce the degree of deceleration, making it possible to stop the vehicle in an appropriate parking position.

[0060] According to this modification, by providing support for not only route but also acceleration and deceleration, parking can be made at a more appropriate location and at an appropriate speed.

[0061] (Variation 7) The vehicle control assist unit 15 may control the steering reaction force. The vehicle control assist unit 15 in this modification applies a steering load (steering reaction force) according to the steering angle of the driver, similar to a normal steer-by-wire. That is, a steering input independent of the reaction force received at the front wheel steering angle is applied by the steering reaction force actuator 102 via the vehicle control assist unit 15. For example, in the case of parking backward in the first embodiment, the user-operated steering angle 62 and the assisted rear steering angle 63 are different, but a reaction force is applied when the steering angle is turned without control.

[0062] According to this modification, the following effects can be obtained. (9) The operation assistance content determination unit 14 calculates the assistance amount for each of the steering amount and the steering reaction force independently. Therefore, the driver operates the steering with the same feeling (reaction force) as in a normal steering operation, so that the driver can operate the steering without feeling any discomfort, and the vehicle 1 can be stopped at an appropriate position by the control of the front wheel steering angle by the vehicle control assistance unit 15.

[0063] The steering reaction force may be applied as follows: A steering reaction force may be generated so as to follow a steering angle corresponding to a standard steering angle. This assists the driver in performing steering operation closer to the standard. This allows the driver to sense deviations from the standard via the steering wheel, making it easier for the driver to perform steering closer to the standard.

[0064] (Variation 8) The parking position selection unit 11 may adjust the parking position candidate 825 for the vehicle 1 based on the positions of the passengers in the vehicle 1. For example, when there is no passenger sitting in the passenger seat, the parking position selection unit 11 may adjust the parking position candidate 825 so that the distance between the passenger door and the obstacle is small and the distance between the driver's door and the obstacle is large.

[0065] (Variation 9) In the first embodiment described above, the parking position candidate 825 is defined as a combination of the position and orientation of the vehicle 1. However, the parking position candidate 825 may be limited to the position of the vehicle 1, and the orientation of the vehicle 1 may not be included in the parking position candidate 825.

[0066] (Variation 10) In the first embodiment described above, the gain 64 is increased according to the progress of the parking operation. However, in cases where safety is a concern, the gain 64 may be increased temporarily regardless of the progress of the parking operation. For example, if there is a possibility that the vehicle 1 will collide with an obstacle, the gain 64 may be increased to temporarily increase the operation assistance amount 827. Furthermore, when a pedestrian is detected, not only may the operation assistance amount 827 be increased to avoid the pedestrian, but the speed of the vehicle 1 may also be forcibly reduced.

[0067] (Variation 11) The parking assistance device 10 may, as necessary, prompt the driver to operate the vehicle 1. For example, the input / output device 404, such as a liquid crystal display or a speaker, may be used to notify the driver that the vehicle 1 is parking in reverse but needs to move forward for adjustment. The liquid crystal display may also be used to display procedures for turning the vehicle 1.

[0068] (Variation 12) In the first embodiment described above, the progress of the parking operation is confirmed at relatively short time intervals, and the gain 64 is changed continuously. However, the update frequency of the gain 64 by the operation assistance content determination unit 14 does not necessarily have to be high. For example, the gain 64 may be updated every time the vehicle 1 moves a predetermined distance, such as one-fifth or one-third of the distance from the initial position A1 to the parking position candidate 825, or may be updated at a relatively long interval, such as one minute. In this case, the update frequency of the gain 64 is reduced, and the gain 64 changes discontinuously.

[0069] (Variation 13) In the first embodiment described above, a satellite navigation system is used to acquire the position of the vehicle 1. However, instead of using a satellite navigation system, the position of the vehicle 1 may be identified by comparing a high-precision map with the topography around the vehicle 1.

[0070] (Variation 14) In the first embodiment described above, the support level determined by the support level determination unit 14-1 is used as the gain 64 as is. However, the support level and the gain 64 do not have to be exactly the same. The relationship between the support level and the gain 64 is such that the gain 64 increases or remains constant as the support level increases. In other words, the relationship is such that the gain 64 at least does not decrease as the support level increases. For example, the gain 64 may be set to zero until the support level reaches a predetermined value.

[0071] --Second embodiment-- A second embodiment of a parking assistance system and parking assistance method will be described with reference to Figures 10 and 11. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and differences will be mainly described. Points that are not particularly described are the same as those in the first embodiment. This embodiment differs from the first embodiment mainly in that the gain is changed according to the estimation accuracy of the parking state intended by the driver. In other words, the estimation accuracy in this embodiment can be said to indicate the progress in the first embodiment.

[0072] 10 is a system configuration diagram of parking assistance device 10A in the second embodiment. Parking assistance device 10A includes an accuracy calculation unit 13 in addition to the configuration of parking assistance device 10 in the first embodiment. Surroundings organized data 821, vehicle state data 822, operation amount data 823, and reference trajectory 826 are input to accuracy calculation unit 13. Accuracy calculation unit 13 calculates estimated accuracy 828 of the parking state intended by the driver.

[0073] The accuracy calculation unit 13 calculates the estimation accuracy 828 based on the following guidelines: (1) The closer the distance between the parking position where the vehicle 1 will be finally stopped and the current position of the vehicle 1, the higher the estimation accuracy 828. (2) The shift state is in the reverse position, the higher the estimation accuracy 828. (3) The steering wheel operation increases the estimation accuracy 828. (4) The slower the vehicle speed, the higher the estimation accuracy 828. (5) The more the brake pedal is depressed, the higher the estimation accuracy 828. (6) The smaller the deviation between the standard trajectory 826 and the driver's trajectory, the higher the estimation accuracy 828. (7) The shorter the distance to obstacles on the path, the higher the estimation accuracy 828. (8) The larger the parking space, the higher the estimation accuracy 828. (9) The direction of the driver's face and line of sight is detected using a camera or the like installed inside the vehicle, and when the time during which this direction matches the parking position exceeds a predetermined threshold, the estimation accuracy 828 increases. The "deviation between the standard trajectory 826 and the driver's trajectory" in (6) above is, for example, the deviation between the standard steering angle and the steering angle actually operated by the driver.

[0074] The accuracy calculation unit 13 combines these indicators and calculates the accuracy by using, for example, the sum or product of the values ​​of each indicator. However, it is not essential to use all of the above (1) to (9), and the accuracy calculation unit 13 may use at least one of (1) to (9) to calculate the accuracy.

[0075] FIG. 11 is a diagram showing changes in the steering angle, etc., and corresponds to FIG. 5 in the first embodiment. However, in FIG. 11, an estimation accuracy 828 is added in the second row from the top. In FIG. 11, as in FIG. 5, the further to the right in the figure, the closer to the final stopping position Aend, so the further to the right in the figure, the larger the estimation accuracy 828. In addition, it further increases as the driver operates the steering wheel. As this estimation accuracy 828 increases, the gain 64 increases, and the steering angle correction amount increases. As a result, steering angle operation is assisted as in the first embodiment, and parking can be performed in an appropriate position.

[0076] According to the second embodiment described above, the following advantageous effects can be obtained. (10) The parking assistance device 10A includes an accuracy calculation unit 13 that calculates an estimated accuracy 828 of the parking state intended by the driver. The operation assistance content determination unit 14 increases the gain 64 in accordance with the estimated accuracy 828. Therefore, the parking assistance device 10A increases the gain 64 in accordance with the progress of the parking state intended by the driver, and can gradually increase the amount of operation assistance without causing the driver any discomfort.

[0077] (11) The accuracy calculation unit 13 calculates the estimated accuracy 828 using at least one of the amount of steering operation by the driver, the amount of accelerator operation by the driver, the amount of braking operation by the driver, the deviation from the reference trajectory 826, the relationship between the parking position candidate 825 and the position of the vehicle 1, the driver state, and the speed of the vehicle 1. Therefore, the parking assistance device 10A can evaluate the progress of the parking operation using various scales and assist the driver in parking.

[0078] (Modification 1 of the second embodiment) The reference trajectory generating unit 12 may regenerate the reference trajectory 826 when there is a large change in the estimation accuracy 828. Specifically, the reference trajectory generating unit 12 may regenerate the reference trajectory 826 when the absolute value of the change in the estimation accuracy 828 per predetermined time period or when the vehicle 1 travels a predetermined distance is greater than a predetermined threshold.

[0079] (Modification 2 of the second embodiment) The accuracy calculation unit 13 may lower the estimation accuracy 828 based on the state of the parking position candidate 825 or the reference route 51, in other words, may reduce the estimation accuracy 828. For example, the estimation accuracy 828 may be reduced when a puddle or an obstacle is present in the parking position candidate 825 or when an obstacle or a moving object is present on the reference route 51. In particular, the estimation accuracy 828 may be reduced further when a pedestrian is detected.

[0080] -Third embodiment- A third embodiment of a parking assistance system and a parking assistance method will be described with reference to Figures 12 to 15. In the following description, the same components as those in the second embodiment are designated by the same reference numerals, and differences will be mainly described. Points that are not particularly described are the same as those in the second embodiment. This embodiment differs from the second embodiment mainly in that it can handle cases where there are multiple parking position candidates 825.

[0081] The configuration of the parking assistance device 10A in this embodiment is the same as that in the second embodiment. However, when there are multiple positions and orientations where the vehicle 1 may be stopped, the parking position selection unit 11 in this embodiment calculates multiple parking position candidates 825. Specifically, in the first embodiment, when there are multiple candidate parking positions, the parking position selection unit 11 narrows down the parking position candidates 825 to one using some criterion, but in this embodiment, multiple parking position candidates 825 may be output. When the parking position selection unit 11 calculates multiple parking position candidates 825, the standard trajectory generation unit 12 calculates multiple standard trajectories 826. The accuracy calculation unit 13 calculates an accuracy for each of the multiple calculated standard trajectories 826 and changes the gain based on the largest accuracy.

[0082] FIG. 12 shows a view of parking lot 30A from above. Parking lot 30A has parallel upper boundary line 31 and lower boundary line 32 at the top and bottom of the illustration. Parking lot 30A has multiple white lines perpendicular to lower boundary line 32, which indicate six parking spaces. Of these six parking spaces, all but the leftmost, third from the left, and rightmost are occupied by other vehicles. For convenience, the leftmost space will be referred to as section 1 801, the third from the left as section 2 802, and the rightmost space as section 3 803. Section 1 801 is the area between first white line 121 and second white line 122. Section 2 802 is the area between third white line 123 and fourth white line 124. Section 3 803 is the area between sixth white line 126 and seventh white line 127.

[0083] First, when the driver drives vehicle 1 and the vehicle approaches the entrance to the parking lot, the start determination unit 19 automatically starts parking assistance as follows: That is, the start determination unit 19 compares the position A1 of vehicle 1 with map data, and since the vehicle 1 is near the entrance to the parking lot and the front of the vehicle 1 is facing the parking lot, it estimates that the driver intends to enter the parking lot and starts parking assistance. Hereinafter, the position of vehicle 1 when parking assistance is started will be referred to as the initial position A1.

[0084] When parking assistance begins, the parking position selection unit 11 selects a first section 801, a second section 802, and a third section 803 as available parking spaces based on external data from a camera or the like. The parking position selection unit 11 also selects both the upward and downward directions of the vehicle 1 in each section. As described above, the parking position candidate 825 is a combination of position and direction, and thus six parking position candidate 825 are selected by combining three positions and two directions. The stopping position of the vehicle 1 in the first section 801 is the first section stopping position 801Z, the stopping position of the vehicle 1 in the second section 802 is the second section stopping position 802Z, and the stopping position of the vehicle 1 in the third section 803 is the third section stopping position 803Z. The first section stopping position 801Z is preferably located in the center between the first white line 121 and the second white line 122. The second section stopping position 802Z is ​​preferably located in the center between the third white line 123 and the fourth white line 124. The third section stopping position 803Z is preferably located in the center between the sixth white line 126 and the seventh white line 127.

[0085] Fig. 13 is a diagram showing a movement path generated by the reference trajectory generating unit 12. The reference trajectory generating unit 12 calculates a reference trajectory 826 from the current position of the vehicle 1 to each parking position candidate 825. In Fig. 13, the path when parking forward into the first section 801 is indicated as 801F, the path when parking forward into the second section 802 is indicated as 802F, the path when parking forward into the third section 803 is indicated as 803F, the path when parking backward into the first section 801 is indicated as 801B, the path when parking backward into the second section 802 is indicated as 802B, and the path when parking backward into the third section 803 is indicated as 803B.

[0086] 14 is a diagram showing the reference trajectory 826 and the trajectory of vehicle 1 when the driver parks facing forward in second section 802. Vehicle 1 travels from initial position A1 through intermediate position 802-2 to second section stopping position 802Z. The driver moves vehicle 1 slightly to the left of the direction of travel from initial position A1 to reach intermediate position 802-2, and then begins steering to the right to stop vehicle 1 at second section stopping position 802Z.

[0087] FIG. 15 is a diagram showing changes in the steering angle, etc., and corresponds to FIG. 11 of the second embodiment. The estimation accuracy 828 shown in the second row from the top is assigned the same symbols as the routes shown in FIG. 11. Of the guidelines (1) to (9) for calculating the accuracy shown in the second embodiment, (1) and (6) vary depending on the route. That is, the difference between the estimation accuracy 828 shown in FIG. 15 is due to (1) the distance to the parking position and (6) the deviation between the standard trajectory 826 and the driver's trajectory.

[0088] First, at the initial position A1, there is no difference in accuracy for any of the parking position candidates 825. When the vehicle 1 starts moving forward, the difference in steering angle from the route 801F shown in FIG. 13 is large, so the estimated accuracy 828 drops more than the others. After that, until the vehicle 1 reaches the intermediate position 802-2, there is no significant difference in the estimated accuracy 828 for routes other than the route 801F. Then, when the vehicle 1 reaches the intermediate position 802-2 and the driver begins steering to the right, the distance to the parking position for the route 802F is short and the difference from the standard route is small, so the estimated accuracy 828 for the route 802F increases. In contrast, the difference from the standard route is large for the other routes, so the estimated accuracy 828 decreases.

[0089] Therefore, the gain 137 related to the deviation from the reference trajectory is set to be higher according to the highest accuracy of the six parking positions and directions. That is, the gain is nearly zero until the intermediate position 802-2 is reached, and then the gain increases sharply, and thereafter the gain increases as the estimated accuracy 828 of the route 802F increases.

[0090] The change in steering angle accompanying a change in gain will be explained. Figure 15 shows the specified steering angle 131, user-operated steering angle 133, and assisted rear steering angle 132 corresponding to the path 801F. Until the intermediate position 802-2 is reached, the gain is nearly 0, so the user-operated steering angle 133 and the assisted rear steering angle 132 are approximately the same. After that, as the deviation from the standard trajectory increases, the gain increases, and accordingly, assistance is provided to approach the standard steering angle. Then, this assistance causes the steering angle to be changed more than the driver's actual operation, so that the vehicle 1 follows a trajectory that is aligned with the standard trajectory, and when the vehicle reaches the second section stopping position 802Z, parking assistance ends.

[0091] According to the above-described third embodiment, the following advantageous effects can be obtained. (12) The parking position selection unit 11 selects a plurality of parking position candidates 825. The reference trajectory generation unit 12 generates a reference trajectory 826 for each parking position candidate 825. The accuracy calculation unit 13 calculates an estimated accuracy 828 for each reference trajectory 826. The operation assistance content determination unit 14 calculates an amount of operation assistance 827 using the highest estimated accuracy 828. Therefore, even when a plurality of parking position candidates 825 are selected, the amount of assistance can be increased little by little based on the highest estimated accuracy 828, thereby enabling the vehicle to accurately stop at the parking position intended by the driver. Furthermore, in this embodiment, since a plurality of parking position candidates 825 are selected, the position where the driver intends to park is likely to be included.

[0092] --Fourth embodiment-- A fourth embodiment of a parking assistance system and a parking assistance method will be described with reference to Fig. 16. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and differences will be mainly described. Points that are not particularly described are the same as those in the first embodiment. This embodiment differs from the first embodiment mainly in that the driver's past history is referenced to generate a model.

[0093] FIG. 16 is a system configuration diagram of a parking assistance device 10C according to the fourth embodiment. In addition to the configuration of the first embodiment, the parking assistance device 10C includes a history recording unit 16 and a history accumulation unit 17. Surroundings organized data 821, vehicle state data 822, and operation amount data 823 are input to the history recording unit 16. The history recording unit 16 stores the driver's operation amount in the history accumulation unit 17 as a driver history. The history accumulation unit 17 is a non-volatile storage area. For example, the history recording unit 16 records the average speed, maximum acceleration and deceleration values, etc., of the vehicle 1 operated by the driver when parking. Furthermore, the history recording unit 16 may associate the operation amount with the surrounding conditions. For example, the history recording unit 16 may associate the relationship between the distance to an obstacle and the speed of the vehicle 1 controlled by the driver.

[0094] The standard trajectory generating unit 12 corrects the standard trajectory 826 by referring to the driver's history stored in the history storing unit 17. For example, the standard trajectory generating unit 12 corrects the standard path 51 based on the driver's history so that the distance to an obstacle is equal to or greater than a predetermined value, and corrects the speed of the vehicle 1 so that it does not exceed the average speed of the driver when parking.

[0095] According to the above-described fourth embodiment, the following advantageous effects can be obtained. (13) The reference trajectory generating unit 12 uses the driving history of the driver to correct the reference trajectory 826. Therefore, the parking assistance device 10C can generate the reference trajectory 826 that reflects the driver's history.

[0096] (Modification 1 of the fourth embodiment) In the fourth embodiment described above, the reference trajectory generating unit 12 refers to the driver's operation history. However, the parking position selecting unit 11 or the accuracy calculating unit 13 may also refer to the driver's operation history. That is, one or more of the parking position selecting unit 11, the reference trajectory generating unit 12, and the accuracy calculating unit 13 may refer to the driver's operation history. For example, the history accumulating unit 17 records a history such as a high rate of reverse parking and parking in an area with as large a distance as possible from surrounding obstacles. The parking position selecting unit 11 then preferentially selects an area where the driver frequently parks as the parking position candidate 825. Furthermore, the accuracy calculating unit 13 calculates a higher accuracy as the parking position approaches an area where the driver frequently parks. According to this modification, generating the reference trajectory 826 and calculating the accuracy based on the driver's history enables parking assistance that is more in line with the driver's intentions.

[0097] (Modification 2 of the fourth embodiment) In the fourth embodiment described above, parking assistance device 10C includes history recording unit 16. However, parking assistance device 10C does not need to include history recording unit 16, and only needs to include at least history accumulation unit 17. In this case, history accumulation unit 17 stores the driver's operation history generated by history recording unit 16 when the driver operates another vehicle, and is stored in parking assistance device 10C.

[0098] (Modification 3 of the fourth embodiment) The history of a plurality of drivers may be stored in the history accumulation unit 17, and the history of the driver driving the vehicle 1 may be read into the reference trajectory generation unit 12. In this case, for example, the vehicle 1 may be provided with a sensor for identifying the driver, and the driver may be identified based on the output of the sensor, or the parking assistance device 10C may be provided with a user interface for selecting a driver.

[0099] (Modification 4 of the fourth embodiment) The reference trajectory generating unit 12 may weight the driver's history stored in the history storage unit 17 based on the number of times it has been recorded, rather than treating it uniformly. For example, if the driver's history has only been recorded a few times, the influence of the history on the reference trajectory 826 is reduced, and if the number of times it has been recorded is large, the influence of the history on the reference trajectory 826 is increased.

[0100] In each of the above-described embodiments and modifications, the functional block configurations are merely examples. Some functional configurations shown as separate functional blocks may be configured as an integrated unit, or a configuration shown in a single functional block diagram may be divided into two or more functions. Furthermore, some of the functions of each functional block may be provided by other functional blocks.

[0101] In each of the above-described embodiments and modifications, the parking assistance device 10 and the like are configured by one or more hardware devices, and these hardware devices are all located inside the vehicle 1. However, the parking assistance device 10 and the like in each of the above-described embodiments and modifications may be realized by a hardware device located inside the vehicle 1 and a hardware device located outside the vehicle 1 operating in cooperation with each other.

[0102] FIG. 17 is a configuration diagram of a vehicle assistance system S that also utilizes hardware devices external to the vehicle 1. The parking assistance device 10 communicates with one or more computers external to the vehicle 1 using the communication device 405 shown in FIG. 2. In the example shown in FIG. 17, the parking assistance device 10 communicates with a first server 901 and a second server 902. The parking assistance device 10 in each of the above-mentioned embodiments and modifications is realized by the cooperation of the parking assistance device 10, the first server 901, and the second server 902. The vehicle assistance system S includes the parking assistance device 10, the first server 901, and the second server 902.

[0103] For example, some of the functions of the parking assistance device 10 in the first embodiment are executed by the first server 901 and the second server 902. The correspondence between the functional blocks and the hardware devices may be fixed or variable. When the correspondence between the functional blocks and the hardware devices is fixed, for example, the parking position selection unit 11 is executed by the first server 901, the reference trajectory generation unit 12 is executed by the second server 902, and the rest are executed by the parking assistance device 10. Also, for example, the parking assistance device 10 executes only the vehicle control assistance unit 15, and the first server 901 and the second server 902 execute the remaining functions. When the correspondence between the functional blocks and the hardware devices is variable, for example, the correspondence may be dynamically changed so that a hardware device with a smaller processing load executes more functional blocks.

[0104] The history accumulation unit 17 in the fourth embodiment is realized by a hardware device external to the vehicle 1, such as the first server 901 or the second server 902, which has the following advantage: Since the same history accumulation unit 17 can be accessed from parking assistance devices 10 mounted on different vehicles, a reference trajectory 826 that reflects the driver's history can be generated even when a certain driver drives a different vehicle.

[0105] In the above-described embodiments and modifications, the program is stored in a ROM (not shown), but the program may be stored in a non-volatile memory. The parking assistance device may also include an input / output interface (not shown), and the program may be loaded from another device as needed via the input / output interface and a medium available to the parking assistance device. The medium here refers to, for example, a storage medium detachable from the input / output interface, or a communication medium, i.e., a wired, wireless, or optical network, or a carrier wave or digital signal propagating through the network. Some or all of the functions implemented by the program may be implemented by a hardware circuit or FPGA.

[0106] The above-described embodiments and modifications may be combined with each other. For example, the first embodiment is described as providing assistance with steering amount, the sixth modification is described as providing assistance with acceleration / deceleration, and the seventh modification is described as providing assistance with steering reaction force. However, the parking assistance device 10 may provide assistance with two or more of steering amount, acceleration / deceleration, and steering reaction force. While various embodiments and modifications have been described above, the present invention is not limited to these. Other aspects conceivable within the scope of the technical concept of the present invention are also included within the scope of the present invention. [Explanation of symbols]

[0107] 1: Vehicle 10, 10A, 10C: Parking assistance device 11: Parking position selection section 12: Normative trajectory generation part 13: Accuracy calculation section 14: Operation support amount determination section 15: Vehicle control support unit 16: History recording section 17: History storage unit 51: Normative pathway 61: Standard steering angle 64: Gain 137: Gain 141: Standard speed 822: Vehicle status data 823: Operation amount data 824: Operation support amount 825: Parking location options 826 : Normative orbit 827: Operation support amount 828: Estimated accuracy

Claims

1. a parking position candidate extraction unit that extracts parking position candidates that are candidates for positions where the vehicle is to be parked; a reference trajectory generating unit that generates a reference trajectory to the parking position candidate; a vehicle control assistance unit that performs vehicle control to assist a driver in parking a vehicle based on the reference trajectory; a vehicle control assistance level determination unit that determines a vehicle control assistance level, which is a level of assistance for the vehicle control by the vehicle control assistance unit; The vehicle control assistance level determination unit increases the vehicle control assistance level depending on the progress of the parking operation.

2. 2. The parking assistance system according to claim 1, a vehicle control assistance amount determination unit that calculates an operation assistance amount by multiplying a deviation, which is a deviation of the state of the vehicle from the reference trajectory, by the vehicle control assistance degree as a gain; The vehicle control assistance unit assists the driver in the parking operation based on the operation assistance amount.

3. 2. The parking assistance system according to claim 1, The vehicle control assistance unit starts assisting the parking operation when the parking position candidate is extracted.

4. 2. The parking assistance system according to claim 1, a probability calculation unit that calculates an estimated probability of the parking state intended by the driver, the probability calculation unit indicating the progress status; The vehicle control assistance level determination unit increases the vehicle control assistance level in accordance with the estimation accuracy.

5. 5. The parking assistance system according to claim 4, The parking position candidate extraction unit selects a plurality of the parking position candidates, the reference trajectory generating unit generates the reference trajectory for each of the parking position candidates, the accuracy calculation unit calculates the estimated accuracy for each of the reference trajectories, The vehicle control assistance level determination unit increases the vehicle control assistance level according to the highest estimation accuracy.

6. 2. The parking assistance system according to claim 1, The parking assistance system further includes a restriction on the direction in which the vehicle is parked, in the parking position candidate.

7. 2. The parking assistance system according to claim 1, The vehicle control assistance degree determination unit calculates the vehicle control assistance degree for at least one of a steering amount, acceleration / deceleration, and a steering reaction force.

8. 2. The parking assistance system according to claim 1, The vehicle control assistance degree determination unit calculates the vehicle control assistance degree independently for each of the steering amount and the steering reaction force.

9. 2. The parking assistance system according to claim 1, the progress status is a distance from the current position of the vehicle to the parking position candidate, The vehicle control assistance level determination unit increases the vehicle control assistance level as the distance from the current position of the vehicle to the parking position candidate becomes shorter.

10. 5. The parking assistance system according to claim 4, the accuracy calculation unit calculates the estimated accuracy using at least one of an amount of steering operation by the driver, an amount of accelerator operation by the driver, an amount of brake operation by the driver, a deviation from the reference trajectory, a relationship between the parking position candidate and the position of the vehicle, a driver state, and a speed of the vehicle.

11. 2. The parking assistance system according to claim 1, The reference trajectory generating unit generates at least one of a reference path, a steering angle, and an acceleration / deceleration as the reference trajectory.

12. 2. The parking assistance system according to claim 1, The reference trajectory generating unit generates the reference trajectory based on at least one of a vehicle state and an external sensor.

13. 13. The parking assistance system of claim 12, The reference trajectory generation unit corrects the reference trajectory using a driving history of the driver.

14. 2. The parking assistance system according to claim 1, The vehicle control assistance level determination unit continuously changes the vehicle control assistance level.

15. 1. A parking assistance method executed by one or more computers, comprising: a parking position candidate extraction step of extracting parking position candidates that are candidates for positions where the vehicle is to be parked; a reference trajectory generating step of generating a reference trajectory to the parking position candidate; a vehicle control assistance step of performing vehicle control to assist a driver in parking a vehicle based on the reference trajectory; a vehicle control assistance level determination step of determining a vehicle control assistance level, which is a level of vehicle control assistance in the vehicle control assistance step; In the vehicle control assistance level determination step, the vehicle control assistance level is increased according to a progress status of the parking operation.

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