Parking assistance method and parking assistance device

Abstract

In the parking assistance method, the actual trajectory of the vehicle moving from the starting point to the target parking position when parking the vehicle manually is stored as the actual driving trajectory (S2), the first target driving trajectory, which is the trajectory from the starting point to the target parking position calculated based on the relative position between the starting point and the target parking position of the actual driving trajectory, is calculated (S4), and the deviation range, which is the range of the actual driving trajectory that includes a part deviating from the first target driving trajectory by more than a first specified distance, is calculated (S5). A certain point within the deviation range is set as the target intermediate position (S6). When assisting the vehicle to park at the target parking position, the parking start position, which is the position of the vehicle at the start of parking, and the second target driving trajectory, which is the trajectory from the parking start position via the target intermediate position to the target parking position, are calculated (S14), and parking assistance control for assisting the vehicle to move along the second target driving trajectory is executed (S15).

Description

Technical Field

[0001] The present invention relates to a parking assistance method and a parking assistance device. Background Art

[0002] In Patent Document 1 below, a parking assistance device has been described. The parking assistance device detects the positions of obstacles within a detection range around the own vehicle at a parking start position, generates a movement route that starts from the parking start position, avoids the obstacles, and moves to a parking target position, and assists the movement along the movement route.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-60223 Summary of the Invention

[0006] Technical Problem to be Solved by the Invention

[0007] In a case where there are restrictions on the route along which the vehicle can move from the parking start position to the target parking position (for example, fixed obstacles or a restricted vehicle movement range), even if a target travel trajectory from the parking start position to the target parking position is generated based on the relative position of the parking start position with respect to the target parking position, there are cases where the vehicle cannot actually move along the target travel trajectory.

[0008] An object of the present invention is to calculate a target travel trajectory along which the vehicle can move from the parking start position to the target parking position even when there are restrictions on the route along which the vehicle can move from the parking start position to the target parking position.

[0009] Technical Solution for Solving the Technical Problem

[0010] In a parking assistance method according to one aspect of the present invention, the actual trajectory along which the vehicle moves from the starting point to the target parking position when parking the vehicle by manual driving is stored as an actual travel trajectory, a first target travel trajectory from the starting point to the target parking position calculated based on the relative position between the starting point and the target parking position of the actual travel trajectory is calculated, and a range including a portion of the actual travel trajectory that deviates from the first target travel trajectory by more than a first specified distance, that is, a deviation range, is calculated. A certain point within the deviation range is set as a target intermediate position. When assisting the vehicle to park at the target parking position, a second target travel trajectory from the position of the vehicle at the start of parking, that is, the parking start position, via the target intermediate position to the target parking position is calculated, and parking assistance control for assisting the vehicle to move along the second target travel trajectory is executed.

[0011] Effects of the Invention

[0012] According to the present invention, even if there are restrictions on the route along which the vehicle can move from the parking start position to the target parking position, it is possible to calculate a target travel trajectory along which the vehicle can move from the parking start position to the target parking position.

[0013] The objects and advantages of the present invention are embodied and achieved by the main components and their combinations shown in the claims. Both the foregoing general description and the following detailed description should be construed as illustrative and explanatory only and not as limiting the present invention as defined by the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a diagram showing a general configuration example of a parking assistance device.

[0015] Figure 2A is an explanatory diagram of an example of a parking assistance method according to an embodiment.

[0016] Figure 2B is an explanatory diagram of an example of a parking assistance method according to an embodiment.

[0017] Figure 3 is Figure 1 a block diagram of an example of the functional configuration of a controller of

[0018] Figure 4A is an explanatory diagram of an example of setting a target intermediate position.

[0019] Figure 4B is an explanatory diagram of an example of setting a target intermediate position.

[0020] Figure 5A is an explanatory diagram of an example of calculating a target travel trajectory.

[0021] Figure 5B is an explanatory diagram of an example of calculating a target travel trajectory.

[0022] Figure 6 is a flowchart of an example of processing performed when parking by manual driving.

[0023] Figure 7 is a flowchart of an example of processing performed when implementing parking assistance. DETAILED DESCRIPTION OF THE INVENTION

[0024] (Configuration)

[0025] Refer to Figure 1。The vehicle 1 is equipped with a parking assistance device 10 that assists the vehicle 1 in parking at a target parking position. The parking assistance device 10 assists the vehicle 1 in traveling along a target travel trajectory from the current position to the target parking position. The parking assistance performed by the parking assistance device 10 has various modes. For example, the automatic driving of the vehicle 1 can be controlled in such a way that the vehicle 1 travels along the target travel trajectory to the target parking position. Controlling the automatic driving of the vehicle 1 in such a way that the vehicle 1 travels along the target travel trajectory to the target parking position means controlling all or part of the steering angle, driving force, and braking force of the vehicle, and automatically implementing all or part of the control for the vehicle 1 to travel along the target travel trajectory. In addition, the vehicle 1 can also be assisted in parking by displaying the target travel trajectory and the current position of the vehicle 1 on a display device that can be visually confirmed by the occupants of the vehicle 1.

[0026] The positioning device 11 measures the current position of the vehicle 1. The positioning device 11, for example, has a Global Navigation Satellite System (GNSS) receiver. The GNSS receiver can also be, for example, a Global Positioning System (GPS) receiver, etc.

[0027] The Human Machine Interface (HMI) 12 is an interface device that receives and transmits information between the parking assistance device 10 and the occupants. The HMI 12 includes: a display device that can be visually confirmed by the occupants of the vehicle 1, a speaker or buzzer, and operating elements (buttons, switches, joysticks, knobs, touch panels, etc.).

[0028] The external sensor 14 detects objects within a specified distance range from the vehicle 1. The external sensor 14 detects the relative position of the objects existing around the vehicle 1 with respect to the vehicle 1, the distance between the vehicle 1 and the objects, and the direction in which the objects exist, etc., of the surrounding environment of the vehicle 1. The external sensor 14 can also include, for example, a camera that captures the surrounding environment of the vehicle 1. The camera can also be, for example, a panoramic monitoring camera that captures the surrounding of the vehicle 1 and generates a captured image converted into an aerial view image (panoramic monitoring image). The external sensor 14 can also include ranging devices such as sonar, laser rangefinder, radar, and LiDAR (Light Detection and Ranging) lidar.

[0029] The vehicle sensor 15 detects various information (vehicle information) of the vehicle 1. The vehicle sensor 15 may also include, for example: a vehicle speed sensor that detects the traveling speed of the vehicle 1, a wheel speed sensor that detects the rotational speed of each tire of the vehicle 1, a triaxial acceleration sensor (G sensor) that detects the acceleration (including deceleration) in three axial directions of the vehicle 1, a steering angle sensor that detects the steering angle of the steering wheel, a steering angle sensor that detects the steering angle of the steering wheel, a gyro sensor that detects the angular velocity of the vehicle 1, and a yaw rate sensor that detects the yaw rate.

[0030] The controller 16 is an electronic control unit that performs parking assist control of the vehicle 1. The controller 16 includes a processor 20 and peripheral accessories such as a storage device 21. The processor 20 may also be a CPU or an MPU, for example. The storage device 21 may also have: a semiconductor storage device, a magnetic storage device, an optical storage device, and the like. The functions of the controller 16 described below are realized, for example, by the processor 20 executing a computer program stored in the storage device 21. It should be noted that the controller 16 may also be formed by dedicated hardware for performing each information process described below.

[0031] The steering actuator 18a controls the steering direction and the steering amount of the steering mechanism of the vehicle 1 according to the control signal of the controller 16. The accelerator actuator 18b controls the accelerator opening of the engine or the drive motor, that is, the drive device, according to the control signal of the controller 16. The brake actuator 18c operates the braking device according to the control signal of the controller 16.

[0032] Next, the parking assist control performed by the parking assist device 10 will be described. In the parking assist control, the parking assist device 10 calculates the relative position of the parking start position with respect to the target parking position Pt. The parking start position is the position at the moment when the vehicle 1 starts the parking assist control toward the target parking position Pt. The parking assist device 10 calculates a target travel trajectory Tt for moving the vehicle 1 from the parking start position to the target parking position Pt based on the relative position of the parking start position with respect to the target parking position Pt. The parking assist device 10 executes parking assist control to assist the vehicle 1 in moving along the target travel trajectory Tt. The target travel trajectory Tt is an example of the "second target travel trajectory" in the claims.

[0033] The relative position of the parking start position with respect to the target parking position Pt may also be calculated, for example, by previously storing the feature points and feature amounts of the objects around the target parking position Pt and based on the stored feature points and feature amounts, as well as the feature points and feature amounts of the objects detected around the vehicle 1.

[0034] For example, when the parking assist device 10 parks the vehicle 1 at the target parking position Pt through manual driving, it detects the feature points and feature quantities of the objects around the target parking position Pt, and stores the position and feature quantity of the feature points relative to the target parking position Pt in the storage device 21. The operation mode in which the parking assist device 10 stores the position and feature quantity of the feature points of the object in the storage device 21 is referred to as the "object learning mode".

[0035] On the other hand, the operation mode of assisting the vehicle 1 to park at the target parking position Pt is referred to as the "parking assist mode". In the parking assist mode, the parking assist device 10 calculates the relative position of the parking start position with respect to the target parking position Pt based on the stored position and feature quantity of the feature points of the objects around the target parking position Pt and the position and feature quantity of the feature points of the objects detected around the vehicle 1. Based on the calculated relative position, it calculates the target travel trajectory Tt and executes the parking assist control to assist the vehicle 1 to move along the target travel trajectory Tt.

[0036] It should be noted that the description in this specification is not intended to limit the technical scope of the present invention by the method of calculating the relative position of the parking start position with respect to the target parking position Pt. The present invention can be widely applied to the method of calculating the target travel trajectory from the parking start position to the target parking position Pt. That is, the relative position of the parking start position with respect to the target parking position Pt can be obtained by various methods. For example, the parking frame line or parking space around the vehicle 1 can be detected by the camera of the external sensor 14 to detect the target parking position Pt, and the parking start position with respect to the target parking position Pt can be calculated.

[0037] As described above, in the parking assist mode, the target travel trajectory Tt, which is the trajectory for the vehicle 1 to move from the parking start position to the target parking position Pt, is calculated. However, there may be restrictions on the route for the vehicle to move from the parking start position to the target parking position Pt.

[0038] For example, there are fixed obstacles such as pillars or trees between the parking start position and the target parking position Pt, or the space where the vehicle can move (i.e., the movable range) is limited. In the above cases, even if the target travel trajectory is generated based on the relative position of the parking start position with respect to the target parking position Pt, there may be cases where the vehicle cannot move along the target travel trajectory.

[0039] In addition, when correcting the target travel trajectory during the movement from the parking start position to the target parking position Pt in order to avoid the above-mentioned obstacles or restrictions, there will be no situation where a smooth target travel trajectory cannot be generated.

[0040] Therefore, the parking assistance device 10 of the embodiment stores the actual trajectory (hereinafter referred to as "actual driving trajectory") of the vehicle 1 moving to the target parking position Pt when the vehicle 1 is parked by manual driving. Refer to Figure 2A . The solid line Ta represents the actual driving trajectory of the vehicle 1 moving from the starting point (starting position) Ps to the target parking position Pt by manual driving.

[0041] Based on the actual driving trajectory Ta, the parking assistance device 10 sets a target intermediate position (position Pi1 in the example of Figure 2A ) through which the vehicle 1 passes in the middle of moving from the parking start position to the target parking position Pt.

[0042] In order to set the target intermediate position, the parking assistance device 10 calculates the trajectory from the starting point Ps of the actual driving trajectory Ta to the target parking position Pt based on the relative positions of the starting point Ps and the target parking position Pt of the actual driving trajectory Ta. The trajectory calculated for the setting of the target intermediate position is referred to as "generated trajectory". The generated trajectory is an example of the "first target driving trajectory" or the "third target driving trajectory" in the claims. For example Figure 2A shows a generated trajectory Tc1 (dashed line).

[0043] The parking assistance device 10 calculates a deviation range, which is a range of the actual driving trajectory Ta that includes a portion deviating from the generated trajectory by more than a first specified distance d1. For example Figure 2A shows a deviation range R1 of the actual driving trajectory Ta that includes a portion deviating from the generated trajectory Tc1 by more than the first specified distance d1.

[0044] In the following description, the term "deviation amount" is used to represent the deviation amount between the generated trajectory and the actual driving trajectory Ta. For example, the deviation amount can be defined as the distance between the actual driving trajectory Ta and the generated trajectory in the normal direction of the actual driving trajectory Ta. For example Figure 2A shows the deviation amount dd1 between the generated trajectory Tc1 and the actual driving trajectory Ta. Additionally Figure 2B shows the deviation amount dd1 with respect to the position along the actual driving trajectory Ta. The point P1 is the point on the actual driving trajectory Ta where the deviation amount dd1 is the largest.

[0045] In addition, a portion of the actual driving trajectory Ta that deviates from the generated trajectory by more than a first specified distance d1 is denoted as the "deviation portion". For example, when the deviation amount at a certain location on the actual driving trajectory Ta is the first specified distance d1 and the deviation amounts before and after it are less than the first specified distance d1, the deviation portion is a single location on the actual driving trajectory Ta. Another example is that when the deviation amounts at two locations on the actual driving trajectory Ta are the first specified distance d1, and it is continuous in the section of the actual driving trajectory Ta between the two locations and the deviation amount is greater than the first specified distance d1, the section between the two locations is a single deviation portion. It should be noted that the first specified distance d1 is the distance at which, when parking the vehicle 1 by manual driving, it is determined that the driver of the vehicle 1 has corrected the trajectory to avoid an obstacle, and it is a pre-determined distance. The trajectory when parking the vehicle 1 by manual driving has some differences for each driver. Therefore, the first specified distance d1 can be set in advance on the basis of considering the driving trajectory differences of each driver obtained through experiments or simulations, etc.

[0046] The parking assistance device 10 can also calculate a deviation range as a range including a part or all of the deviation portion. For example, a single location on the actual driving trajectory Ta included in the deviation portion can be calculated as the deviation range. For example, the location on the actual driving trajectory Ta with the largest deviation amount in the deviation portion with a non-zero length can also be calculated as the deviation range. For example, the location P1 can be calculated as the deviation range. Figure 2A of the location P1 as the deviation range.

[0047] Another example is that multiple locations on the actual driving trajectory Ta included in the deviation portion can also be calculated as the deviation range. For example, multiple locations included in the deviation portion with a non-zero length can be calculated as the deviation range.

[0048] In addition, for example, a part or all of the section of the deviation portion with a non-zero length can also be calculated as the deviation range.

[0049] In addition, when there are multiple deviation portions, a single location, multiple locations, or section included in any of the above deviation portions can also be set as the deviation range. For example, a single location, multiple locations, or section included in a deviation portion arbitrarily selected from the above deviation portions can be set as the deviation range. A single location, multiple locations, or section included in the deviation portion with the largest deviation amount among the above deviation portions can also be set as the deviation range.

[0050] In addition, for example, as a deviation range, a range within a second specified distance d2 from the above-mentioned single location, multiple locations, or section may be designated as the deviation range R1. The second specified distance d2 is appropriately set to be shorter than the first specified distance d1.

[0051] The parking assistance device 10 sets a target intermediate position within the deviation range. The target intermediate position can also be arbitrarily set within the deviation range. For example Figure 2A Fig. shows the target intermediate position Pi1 set within the deviation range R1. The target intermediate position Pi1 can also be set at the same position as the location P1. That is, the target intermediate position can be set at the location on the actual travel trajectory Ta within each deviation range where the deviation from the generated trajectory is the longest.

[0052] The target intermediate position Pi1 can also be set at a position different from the location P1. That is, the target intermediate position can be set at a position different from the location on the actual travel trajectory Ta within each deviation range where the deviation from the generated trajectory is the longest. In Figure 2A the example, it can be set within the range within the second specified distance d2 from the location P1.

[0053] The parking assistance device 10 calculates the trajectory from the parking start position, via the target intermediate position (in Figure 2A the example, it is the target intermediate position Pi1) to the target parking position Pt as the target travel trajectory Tt (dashed line).

[0054] In this way, based on the actual travel trajectory Ta of the vehicle 1 moving from the starting point Ps to the target parking position Pt manually, the target intermediate position is set, and the target travel trajectory Tt from the parking start position, via the target intermediate position to the target parking position Pt is calculated. Thus, even if there are restrictions on the route that the vehicle 1 can move, a target travel trajectory that the vehicle 1 can travel can be generated.

[0055] In addition, since the trajectory via the target intermediate position Pi1 can be generated before starting to move from the parking start position to the target parking position Pt, a smooth target travel trajectory can be generated.

[0056] Next, the functional structure of the controller 16 will be described in detail. Refer to Figure 3 The controller 16 functions as an image conversion unit 40, a self-position calculation unit 41, a feature point detection unit 42, a map data generation unit 43, an actual trajectory acquisition unit 44, an intermediate position setting unit 46, a relative position calculation unit 47, a target trajectory generation unit 48, a steering control unit 49, a vehicle speed control unit 50, and an auxiliary image generation unit 51.

[0057] The image conversion unit 40 converts the captured image of the camera of the external sensor 14 into an aerial view image (panoramic monitoring image) observed from a virtual viewpoint directly above the vehicle 1. Hereinafter, the aerial view image converted by the image conversion unit 40 may sometimes be referred to as the "surrounding image".

[0058] The own position calculation unit 41 calculates the current position of the vehicle 1 on the fixed coordinate system by using a dead reckoning method or the like based on the vehicle information output from the vehicle sensor 15. The fixed coordinate system is a coordinate system in which a specified location is used as the coordinate origin (for example, a map coordinate system). The own position calculation unit 41 may also correct the calculated current position by map matching or the like between the landmark positions around the vehicle 1 detected by the external sensor 14 and the known landmark positions or high-precision map information.

[0059] The feature point detection unit 42 detects the feature points of the landmarks around the vehicle 1 based on the surrounding image output from the image conversion unit 40, and calculates the feature amounts of the feature points. The feature points of the surrounding image are, for example, points that are characteristic as landmarks such as the edge points of the surrounding image. In addition, the feature amount is information indicating the characteristics of the feature points such as the brightness on the image. The positions of the feature points detected from the surrounding image are represented by coordinates in a coordinate system (hereinafter referred to as the "vehicle coordinate system") with the current position of the vehicle 1 as the reference. The detection of the feature points or the calculation of the image feature amounts can be performed, for example, by using methods such as SIFT, SURF, ORB, BRIAK, KAZE, and AKAZE. It should be noted that the time when the feature point detection unit 42 detects the feature points is not particularly limited. For example, the detection can be continuously performed regardless of whether the operation mode of the parking assistance device 10 is the landmark learning mode or the parking assistance mode.

[0060] In addition, the feature point detection unit 42 receives the current position of the vehicle 1 from the own position calculation unit 41. The feature point detection unit 42 generates feature point data including the positions and feature amounts of the detected feature points, and the current position of the vehicle 1 at the time when the feature points are detected. The feature point detection unit 42 outputs the feature point data to the map data generation unit 43 and the relative position calculation unit 47. It should be noted that here, the feature point detection unit 42 only needs to be able to detect at least the positions of the feature points. That is, as the feature point data, it only needs to include at least the positions of the feature points and the current position of the vehicle 1, and it is not necessarily required to detect the feature amounts.

[0061] When the operation mode of the parking assist device 10 is the target learning mode, the map data generation unit 43 stores the feature point data generated by the feature point detection unit 42 in the storage device 21. Hereinafter, the feature points stored in the storage device 21 are sometimes referred to as "learned feature points". In addition, the map data generation unit 43 stores the position of the target parking position Pt in the storage device 21. For example, when the vehicle 1 is located at the target parking position Pt, the user of the vehicle 1 can operate the HMI 12 to input the current position of the vehicle 1 as the target parking position Pt. Further, in the target learning mode, when the user shifts the gear of the vehicle 1 to the parking gear or applies the parking brake, the current position of the vehicle 1 can be detected as the target parking position Pt. By storing the positions of the learned feature points in the vehicle coordinate system, the position of the vehicle 1 in the fixed coordinate system when the learned feature points are detected, and the target parking position Pt in the fixed coordinate system, the relative position relationship between the learned feature points and the target parking position Pt can be stored.

[0062] It should be noted that the method of storing the relative position relationship between the learned feature points and the target parking position Pt is not limited to the above method. For example, the position of the learned feature points in the relative coordinate system with the target parking position Pt as the reference can also be stored.

[0063] The actual trajectory acquisition unit 44 acquires the actual trajectory Ta of the vehicle 1 moving to the target parking position Pt during parking the vehicle 1 at the target parking position Pt by manual driving. For example, the actual trajectory acquisition unit 44 can continuously receive the current position of the vehicle 1 output from the own position calculation unit 41 during parking the vehicle 1 at the target parking position Pt by manual driving, and thereby acquire the actual trajectory Ta based on the point sequence of the current position of the moving vehicle 1.

[0064] It should be noted that the actual trajectory acquisition unit 44 can also take the opportunity of parking the vehicle 1 at the target parking position Pt by manual driving for learning feature points in the target learning mode to acquire the actual trajectory Ta. Alternatively, the actual trajectory Ta can also be acquired when the vehicle 1 is only parked at the target parking position Pt by manual driving without learning feature points. For example, the user of the vehicle 1 can operate the HMI 12 to instruct the start of acquisition of the actual trajectory Ta.

[0065] When the actual trajectory acquisition unit 44 detects that the vehicle 1 has completed parking through manual driving, it completes the acquisition of the actual driving trajectory Ta. The actual trajectory acquisition unit 44 stores the acquired actual driving trajectory Ta in the storage device 21. For example, the user of the vehicle 1 can operate the HMI 12 to instruct the completion of the acquisition of the actual driving trajectory Ta. In addition, the actual trajectory acquisition unit 44 can also detect that the vehicle 1 has completed parking through manual driving when the user shifts the gear of the vehicle 1 to the parking gear, or applies the parking brake, or the current position of the vehicle 1 has reached the target parking position Pt.

[0066] In the case where the vehicle 1 has completed parking through manual driving, the intermediate position setting unit 46 sets the target intermediate position based on the actual driving trajectory Ta. Refer to Figure 4A . When setting the initial target intermediate position Pi1, the intermediate position setting unit 46 calculates the generated trajectory Tc1 from the starting point Ps of the actual driving trajectory Ta to the target parking position Pt. For example, the intermediate position setting unit 46 can calculate the clothoid connecting the starting point Ps and the target parking position Pt as the generated trajectory Tc1. The intermediate position setting unit 46 determines whether there is a deviation portion in the actual driving trajectory Ta that deviates from the generated trajectory Tc1 by more than the first specified distance d1. In the case where the deviation portion does not exist, the intermediate position setting unit 46 does not set the initial target intermediate position Pi1. In this case, the target intermediate position is not set. In the case where the deviation portion exists, the intermediate position setting unit 46 calculates the deviation range R1 including the deviation portion. In the case where there are multiple deviation portions, the deviation range R1 including any one of the above deviation portions is calculated. For example, the deviation range R1 can be set in such a way as to include any selected deviation portion or the deviation portion with the largest deviation amount among the above deviation portions.

[0067] The intermediate position setting unit 46 sets the target intermediate position Pi1 within the deviation range R1. It should be noted that when setting the target intermediate position Pi1, the intermediate position setting unit 46 can also calculate the trajectory from the starting point Ps via the target intermediate position Pi1 to the target parking position Pt, and determine whether the vehicle 1 can move on the calculated trajectory. In the case where it is determined that the vehicle 1 cannot move on the calculated trajectory, the target intermediate position Pi1 can also be reset to another location within the deviation range R1. The intermediate position setting unit 46 can also repeatedly perform the process of resetting the target intermediate position Pi1 within the deviation range R1 until a trajectory on which the vehicle 1 can move can be calculated.

[0068] When setting the target intermediate position Pi1, the intermediate position setting unit 46 calculates a generated trajectory Tc2 from the starting point Ps, via the target intermediate position Pi1, to the target parking position Pt. The generated trajectory Tc2 is an example of the "third target travel trajectory" in the claims. For example, the intermediate position setting unit 46 can calculate the generated trajectory Tc2 by connecting a clothoid curve connecting the starting point Ps and the target intermediate position Pi1 and a clothoid curve connecting the target intermediate position Pi1 and the target parking position Pt. The intermediate position setting unit 46 determines whether there is a deviation portion in the actual travel trajectory Ta that deviates from the generated trajectory Tc2 by more than a first specified distance d1. That is, it determines whether the deviation amount dd2 between the generated trajectory Tc2 and the actual travel trajectory Ta is less than the first specified distance d1 within the range from the starting point Ps to the target parking position Pt. When there is no deviation portion, the intermediate position setting unit 46 does not set a second target intermediate position. In this case, only the target intermediate position Pi1 is set. When there is a deviation portion, the intermediate position setting unit 46 calculates a deviation range R2 including the deviation portion, and sets an additional target intermediate position Pi2 within the deviation range R2. The point P2 is the point on the actual travel trajectory Ta where the deviation amount dd2 is the largest.

[0069] When the intermediate position setting unit 46 has set a plurality of target intermediate positions Pi1, Pi2, it sets the order of the target intermediate positions Pi1, Pi2 (denoted as the "intermediate position order" in the following description) along the actual travel trajectory Ta in the order of being away from the target parking position Pt (i.e., in the order of approaching the starting point Ps). In the following description, the order of setting the target intermediate positions is denoted as the "intermediate position order".

[0070] The intermediate position setting unit 46 calculates a generated trajectory Tc3 from the starting point Ps, via the target intermediate positions Pi1 and Pi2, to the target parking position Pt. The generated trajectory Tc3 is an example of the "third target travel trajectory" in the claims. At this time, the intermediate position setting unit 46 calculates the generated trajectory Tc3 in such a way that it passes through the target intermediate positions Pi1 and Pi2 in accordance with the intermediate position order. That is, it calculates the generated trajectory Tc3 that starts from the starting point Ps, passes through the target intermediate positions Pi1 and Pi2 in the order of approaching the starting point Ps along the actual travel trajectory Ta, and reaches the target parking position Pt. For example, in Figure 4B the example, the generated trajectory Tc3 that passes through in the order of the target intermediate positions Pi1, Pi2 is calculated. For example, the intermediate position setting unit 46 can calculate the generated trajectory Tc3 by connecting a clothoid curve connecting the starting point Ps and the target intermediate position Pi1, a clothoid curve connecting the target intermediate position Pi1 and the target intermediate position Pi2, and a clothoid curve connecting the target intermediate position Pi2 and the target parking position Pt.

[0071] The intermediate position setting unit 46 determines whether there is a deviation portion in the actual travel locus Ta that deviates from the generated locus Tc3 by more than a first specified distance d1. When there is no deviation portion, the intermediate position setting unit 46 does not set the third target intermediate position. In this case, only the target intermediate positions Pi1 and Pi2 are set. When there is a deviation portion, the intermediate position setting unit 46 adds the third target intermediate position by the same method as the method for setting the second target intermediate position Pi2. Hereinafter, the target intermediate positions are added until a generated locus that does not have a portion deviating from the actual travel locus Ta by more than the first specified distance d1 can be generated. When a generated locus that does not have a portion deviating from the actual travel locus Ta by more than the first specified distance d1 can be generated, the intermediate position setting unit 46 completes the setting of the target intermediate positions and stores the set target intermediate positions in the storage device 21.

[0072] Note that there is a case where the restriction on the route along which the vehicle can move to the target parking position Pt (for example, a restricted movable range or an obstacle) is only a temporary restriction. In this case, the target intermediate positions may not be required. Therefore, the intermediate position setting unit 46 may also accept a selection input in which the user of the vehicle 1 selects any one of the set target intermediate positions and store only the selected target intermediate position in the storage device 21.

[0073] For example, a plurality of target intermediate positions set by the intermediate position setting unit 46 are displayed on the display device of the HMI1, and a selection input for selecting the target intermediate position to be stored from among the displayed target intermediate positions is accepted using the operating member of the HMI12. The selection input may be, for example, an input specifying the target intermediate position to be logged in, or an input specifying an unnecessary target intermediate position.

[0074] In addition, for example, when N target intermediate positions are set, all combinations of extracting 1 to N target intermediate positions from the above N target intermediate positions can be set, and the locus from the starting point Ps to the target parking position Pt via the target intermediate positions included in the combination is displayed on the display device of the HMI12, and an input specifying any of the displayed loci is accepted. In this case, the intermediate position setting unit 46 may also store the target intermediate positions passed by the specified locus in the storage device 21.

[0075] Refer to Figure 3。To start the parking assist control for assisting the vehicle 1 to park at the target parking position Pt, the operation mode of the parking assist device 10 is switched to the parking assist mode. For example, the parking assist device 10 can switch the operation mode to the parking assist mode when the vehicle 1 is near the target parking position Pt. At this time, when the gear is switched from the forward gear to the reverse gear, or from the reverse gear to the forward gear, the operation mode can be switched to the parking assist mode. Additionally, the operation mode can also be switched to the parking assist mode when the "parking assist start switch" prepared on the HMI 12 is operated. The conditions for switching the operation mode to the parking assist mode can be set arbitrarily.

[0076] When the operation mode of the parking assist device 10 is switched to the parking assist mode, the relative position calculation unit 47 sets the current position of the vehicle 1 at the moment of starting the parking assist control towards the target parking position Pt as the parking start position Pps. In addition, the relative position calculation unit 47 matches the learned feature points stored in the storage device 21 with the feature points of the feature point data output from the feature point detection unit 42, and associates the same feature points with each other. In the following description, when the operation mode of the parking assist device 10 is the parking assist mode, the feature points detected by the feature point detection unit 42 around the vehicle 1 are referred to as "surrounding feature points".

[0077] The relative position calculation unit 47 calculates the relative position of the parking start position Pps with respect to the target parking position Pt based on the relative position relationship between the surrounding feature points and the vehicle 1, and the relative position relationship between the learned feature points associated with the surrounding feature points and the target parking position Pt. For example, denoting the surrounding feature points as (x i , y i ), and denoting the learned feature points associated with the surrounding feature points (x i , y i ) as (x mi , y mi ) (i = 1 to N). The relative position calculation unit 47 calculates the affine transformation matrix M using the following formula based on the least squares method affine .

[0078]

Equation 1

[0079]

[0080] It is also possible to use the weighted least squares method to calculate the column vector (a1, a2, a3, a4) as shown in the following formula T .

[0081]

Equation 2

[0082]

[0083] The relative position calculation unit 47 uses the following formula to convert the position (targetx m , targety m ) of the target parking position Pt on the fixed coordinate system stored in the storage device 21 into the position (targetx, targety) in the vehicle coordinate system.

[0084]

Equation 3

[0085]

[0086] The position (targetx, targety) of the target parking position Pt in the vehicle coordinate system represents the relative position of the parking start position Pps with respect to the target parking position Pt. The relative position calculation unit 47 outputs the relative position of the parking start position Pps with respect to the target parking position Pt to the target trajectory generation unit 48.

[0087] The target trajectory generation unit 48 calculates the target travel trajectory Tt based on the relative position of the parking start position Pps with respect to the target parking position Pt and the target intermediate positions. Refer to Figure 5A . The target trajectory generation unit 48 calculates the target travel trajectory Tt in such a way that it passes through the target intermediate positions Pi1 and Pi2 in the order of the intermediate positions. That is, it calculates the target travel trajectory Tt that starts from the parking start position Pps, passes through the target intermediate positions Pi1 and Pi2 in the order of the intermediate positions (that is, in the order along the actual travel trajectory Ta, in the order of moving away from the target parking position Pt), and reaches the target parking position Pt. The calculation of the target travel trajectory Tt can apply well-known methods already adopted in the automatic parking device. For example, it can be calculated by using a clothoid curve to connect from the parking start position Pps, via the target intermediate positions Pi1 and Pi2, to the target parking position Pt.

[0088] Refer to Figure 5B . There may be a situation where the target travel trajectory Tt cannot be calculated in such a way as to pass through all the target intermediate positions Pi1 and Pi2 stored in the storage device 21. For example, when the parking start position Pps is closer to the target parking position Pt than a certain target intermediate position (in the example of Figure 5B it is the target intermediate position Pi1), the target travel trajectory Tt cannot be calculated in such a way as to pass through this target intermediate position. The above situation may occur, for example, when the driver parks manually halfway and starts the parking assistance control at a position closer to the target parking position Pt than the starting point Ps of the actual travel trajectory Ta.

[0089] In this case, the target trajectory generation unit 48 sequentially removes the target intermediate positions in the order of the intermediate positions among the target intermediate positions Pi1 and Pi2 read from the storage device 21 (that is, along the actual travel trajectory Ta, in the order of moving away from the target parking position Pt), and calculates the target travel trajectory Tt from the parking start position Pps to the target parking position Pt via the unremoved target intermediate positions. In Figure 5B the example of Figure 5B , the target travel trajectory Tt from the parking start position Pps to the target parking position Pt that removes the target intermediate position Pi1 and passes through the target intermediate position Pi2 is calculated.

[0090] In addition, the target trajectory generation unit 48 calculates a target vehicle speed change diagram for the vehicle 1 to travel along the target travel trajectory Tt. For example, the target vehicle speed change diagram can be a vehicle speed change diagram in which the vehicle accelerates from the parking start position Pps to a pre-determined set speed, decelerates before the target parking position Pt, and stops at the target parking position Pt. The set speed can be set in such a way that the larger the curvature of the calculated target travel trajectory, the lower the speed.

[0091] Refer to Figure 3 The target trajectory generation unit 48 outputs the target travel trajectory Tt and the target vehicle speed change diagram to the steering control unit 49 and the vehicle speed control unit 50, respectively.

[0092] The steering control unit 49 controls the steering actuator 18a so that the vehicle 1 travels along the target travel trajectory Tt. The vehicle speed control unit 50 controls the accelerator actuator 18b and the brake actuator 18c so that the vehicle speed of the vehicle 1 changes according to the target vehicle speed change diagram. Thus, the vehicle 1 is controlled to travel along the target travel trajectory Tt. The auxiliary image generation unit 51 generates a parking assistance image representing the target travel trajectory Tt and the current position of the vehicle 1. For example, the parking assistance image can be an image in which the target travel trajectory Tt and the current position of the vehicle 1 are superimposed on a bird's-eye view image or an overhead view image of the surroundings of the vehicle 1 observed from above. The auxiliary image generation unit 51 displays the parking assistance image on the display device of the HMI 12.

[0093] (Operation)

[0094] Figure 6It is a flowchart showing an example of the process executed during parking by manual driving. In step S1, the feature point detection unit 42 stores the feature points of the objects around the vehicle 1 as learned feature points in the storage device 21. In step S2, the actual trajectory acquisition unit 44 acquires the actual driving trajectory Ta and stores it in the storage device 21. In step S3, the parking assistance device 10 determines whether the vehicle 1 has reached the target parking position Pt. If the vehicle 1 has not reached the target parking position Pt (step S3: N), the process returns to step S1. If the vehicle 1 has reached the target parking position Pt (step S3: Y), the process proceeds to step S4.

[0095] In step S4, the intermediate position setting unit 46 calculates the generated trajectory. In step S5, the intermediate position setting unit 46 determines whether the deviation amount between the generated trajectory and the actual driving trajectory Ta from the starting point Ps of the actual driving trajectory Ta to the target parking position Pt is less than the first specified distance d1. If the deviation amount is not less than the first specified distance d1 (step S5: N), the process proceeds to step S6. If the deviation amount is less than the first specified distance d1 (step S5: Y), the process proceeds to step S7. In step S6, the intermediate position setting unit 46 sets the target intermediate position within the deviation range. In the processing loop S4 - S6, if step S6 is executed more than twice, an increased target intermediate position is set after the second time. Then, the process returns to step S4. In step S7, the set target intermediate position is stored in the storage device 21. Then, the process ends.

[0096] Figure 7 It is a flowchart showing an example of the process during parking assistance. In step S10, the relative position calculation unit 47 calculates the relative position of the target parking position Pt with respect to the current position of the vehicle 1 at the start of parking assistance control, i.e., the parking start position Pps. That is, it calculates the relative position of the parking start position Pps with respect to the target parking position Pt. In step S11, the target trajectory generation unit 48 reads the target intermediate position from the storage device 21. In step S12, the target trajectory generation unit 48 attempts to calculate the target driving trajectory Tt from the parking start position Pps to the target parking position Pt via the read target intermediate position.

[0097] In step S13, the target trajectory generation unit 48 determines whether the target driving trajectory Tt can be calculated. If the target driving trajectory Tt cannot be calculated (step S13: N), the process proceeds to step S14. If the target driving trajectory Tt can be calculated (step S13: Y), the process proceeds to step S15.

[0098] In step S14, the target trajectory generation unit 48 removes the target intermediate position that is the farthest from the target parking position Pt along the actual travel trajectory Ta among the target intermediate positions. Then, the process returns to step S12.

[0099] In step S15, the target trajectory generation unit 48 calculates a target vehicle speed change diagram for the vehicle 1 to travel along the target travel trajectory Tt. The steering control unit 49 controls the steering actuator 18a so that the vehicle 1 travels along the target travel trajectory Tt. The vehicle speed control unit 50 controls the accelerator actuator 18b and the brake actuator 18c so that the vehicle speed of the vehicle 1 changes according to the target vehicle speed change diagram. When the vehicle 1 reaches the target parking position Pt, the process ends.

[0100] (Effects of the Embodiment)

[0101] (1) The controller 16 stores the actual trajectory when the vehicle 1 is parked by manual driving and the vehicle 1 moves to the target parking position Pt as the actual travel trajectory Ta, calculates the first target travel trajectory, which is the trajectory from the starting point Ps of the actual travel trajectory Ta to the target parking position Pt, based on the relative position between the starting point Ps of the actual travel trajectory Ta and the target parking position Pt, and calculates the deviation range, which is the range of the actual travel trajectory Ta that includes the part deviating from the first target travel trajectory by more than the first specified distance. A certain point within the deviation range is set as the target intermediate position. When assisting the vehicle 1 to park at the target parking position Pt, the controller 16 calculates the second target travel trajectory, which is the trajectory from the parking start position Pps, which is the position of the vehicle 1 at the start of parking, via the target intermediate position to the target parking position Pt, and executes the parking assist control to assist the vehicle 1 to move along the second target travel trajectory. In this way, based on the actual travel trajectory Ta, the target intermediate position is set, and the target travel trajectory from the parking start position, via the target intermediate position to the target parking position Pt is calculated. Thus, even if there are restrictions on the route along which the vehicle can move, the target travel trajectory along which the vehicle can travel can be calculated. In addition, since the trajectory via the target intermediate position can be generated before starting to move from the parking start position Pps to the target parking position Pt, a smooth target travel trajectory can be generated.

[0102] (2) The controller 16 can set, within each deviation range, as the target intermediate position a point within the second specified distance range of the point on the actual travel trajectory Ta within the deviation range that is the farthest from the first target travel trajectory.

[0103] The point where the first target travel trajectory calculated by the controller 16 deviates the most from the actual travel trajectory Ta can be presumed to be the point where the line along which the vehicle 1 can move is affected by a restriction. By calculating a trajectory via a target intermediate position set near the above point, a target travel trajectory that satisfies the restriction on the line along which the vehicle can move can be calculated.

[0104] (3) The controller 16 can (a1) calculate a trajectory from the starting point Ps to the target parking position Pt via the target intermediate position, (b1) determine whether the vehicle 1 can move on the calculated trajectory, and (c1) if it is determined that the vehicle 1 cannot move on the calculated trajectory, re-set the target intermediate position at another point within the deviation range. The controller 16 can repeat (a1) to (c1) until it is determined in the above (b1) that the vehicle 1 can move on the calculated trajectory. Thus, a second target travel trajectory can be calculated in a manner such that the vehicle 1 can actually move.

[0105] (4) The controller 16 can also (a2) calculate a trajectory from the starting point Ps to the target parking position Pt via the target intermediate position, i.e., the third target travel trajectory, (b2) determine whether the deviation amount between the third target travel trajectory and the actual travel trajectory Ta within the range from the starting point Ps to the target parking position Pt is less than a first specified distance, and (c2) if the deviation amount within the range from the starting point Ps to the target parking position Pt is not less than the first specified distance, set an additional target intermediate position within the deviation range that includes a portion of the actual travel trajectory Ta that deviates from the third target travel trajectory by more than the first specified distance. The controller 16 can repeat (a2) to (c2) until it is determined in the above (b2) that the deviation amount within the range from the starting point Ps to the target parking position Pt is less than the first specified distance.

[0106] Thus, a second target travel trajectory can be calculated in a manner such that the deviation amount from the actual travel trajectory Ta is less than the first specified distance.

[0107] (5) The controller 16 can accept a selection input from the user of the vehicle 1 to select any of the plurality of set target intermediate positions, and calculate a second target travel trajectory from the parking start position Pps to the target parking position Pt via the target intermediate position selected by the user, thereby avoiding setting unnecessary target intermediate positions.

[0108] When the controller 16 cannot calculate the second target travel trajectory from the parking start position Pps to the target parking position Pt via a plurality of target intermediate positions, it can start removing the target intermediate positions in the order away from the target parking position Pt along the actual travel trajectory Ta, and calculate the second target travel trajectory from the parking start position Pps to the target parking position Pt via the target intermediate positions that have not been removed among the plurality of target intermediate positions. Thus, even if the parking assist control starts from a location near the middle of the actual travel trajectory Ta, the second target travel trajectory to the target parking position Pt can be calculated.

[0109] The controller 16 can control the vehicle 1 so that the vehicle 1 moves from the parking start position Pps to the target parking position Pt along the second target travel trajectory, or can display the second target travel trajectory and the position of the vehicle 1 on a display device that can be visually confirmed by the user of the vehicle 1. Thus, parking of the vehicle 1 can be assisted.

[0110] The controller 16 can calculate the second target travel trajectory by connecting the parking start position Pps and the target intermediate position, and the target intermediate position and the target parking position Pt with clothoid curves respectively. Thus, a smooth second target travel trajectory can be calculated.

[0111] All the examples and conditional terms described herein are for educational purposes to help the reader understand the present invention and the concepts provided by the inventor for the development of the technology, and should be interpreted as not limited to the above examples and conditions described specifically, and the structures of the examples in this specification related to showing the advantages and disadvantages of the present invention. Although the embodiments of the present invention have been described in detail, it should be understood that various changes, substitutions, and corrections can be made without departing from the spirit and scope of the present invention.

[0112] Explanation of reference numerals

[0113] 1 Vehicle; 10 Parking assist device; 11 Positioning device; 12 Human-machine interface; 14 External sensor; 15 Vehicle sensor; 16 Controller; 18a Steering actuator; 18b Accelerator actuator; 18c Brake actuator; 20 Processor; 21 Storage device; 40 Image conversion unit; 41 Own position calculation unit; 42 Feature point detection unit; 43 Map data generation unit; 44 Actual trajectory acquisition unit; 46 Intermediate position setting unit; 47 Relative position calculation unit; 48 Target trajectory generation unit; 49 Steering control unit; 50 Vehicle speed control unit; 51 Auxiliary image generation unit.

Claims

1. A parking assistance method, characterized in that the actual trajectory of the vehicle moving from the starting point to the target parking position when parking the vehicle by manual driving is stored as the actual driving trajectory, a first target driving trajectory, which is the trajectory from the starting point to the target parking position, is calculated based on the relative position between the starting point of the actual driving trajectory and the target parking position, a deviation range, which is the range in the actual driving trajectory that deviates from the first target driving trajectory by more than a first specified distance, is calculated, a certain location within the deviation range is set as the target intermediate position, when assisting the vehicle to park at the target parking position, the parking start position, which is the position of the vehicle at the start of parking, and a second target driving trajectory, which is the trajectory from the parking start position via the target intermediate position to the target parking position, are calculated, a parking assistance control for assisting the vehicle to move along the second target driving trajectory is executed, a point on the actual driving trajectory within the deviation range is set as the target intermediate position.

2. A parking assistance method, characterized in that the actual trajectory of the vehicle moving from the starting point to the target parking position when parking the vehicle by manual driving is stored as the actual driving trajectory, a first target driving trajectory, which is the trajectory from the starting point to the target parking position, is calculated based on the relative position between the starting point of the actual driving trajectory and the target parking position, a deviation range, which is the range in the actual driving trajectory that deviates from the first target driving trajectory by more than a first specified distance, is calculated, a certain location within the deviation range is set as the target intermediate position, when assisting the vehicle to park at the target parking position, the parking start position, which is the position of the vehicle at the start of parking, and a second target driving trajectory, which is the trajectory from the parking start position via the target intermediate position to the target parking position, are calculated, a parking assistance control for assisting the vehicle to move along the second target driving trajectory is executed, (a1) Calculate the trajectory from the starting point via the target intermediate position to the target parking position, (b1) Determine whether the vehicle can move on the calculated trajectory, (c1) If it is determined that the vehicle cannot move on the calculated trajectory, the target intermediate position is reset to another location within the deviation range, Repeat (a1) to (c1) until it is determined in (b1) that the vehicle can move on the calculated trajectory.

3. The parking assistance method according to claim 1 or 2, characterized in that (a2) Calculate a third target driving trajectory, which is the trajectory from the starting point via the target intermediate position to the target parking position, (b2) Determine whether the deviation amount between the third target driving trajectory and the actual driving trajectory within the range from the starting point to the target parking position is less than the first specified distance, (c2) When the deviation amount is not less than the first specified distance within the range from the starting point to the target parking position, an additional target intermediate position is set within the deviation range that includes a portion of the actual driving trajectory that deviates from the third target driving trajectory by more than the first specified distance. Repeat the steps (a2) to (c2) until it is determined in (b2) that the deviation amount within the range from the starting point to the target parking position is less than the first specified distance.

4. The parking assistance method according to claim 1 or 2, characterized in that: A plurality of the target intermediate positions are set within the deviation range. An input of a selection of any one of the plurality of set target intermediate positions selected by the user of the vehicle is received. The second target driving trajectory from the starting parking position via the target intermediate position selected by the user to the target parking position is calculated.

5. The parking assistance method according to claim 1 or 2, characterized in that: A plurality of the target intermediate positions are set within the deviation range. When the second target driving trajectory from the starting parking position via the plurality of target intermediate positions to the target parking position cannot be calculated, the target intermediate positions are removed in the order away from the target parking position along the actual driving trajectory, and the second target driving trajectory from the starting parking position via the target intermediate positions that have not been removed among the plurality of target intermediate positions to the target parking position is calculated.

6. The parking assistance method according to claim 1 or 2, characterized in that: The vehicle is controlled in such a manner that the vehicle moves from the starting parking position to the target parking position along the second target driving trajectory.

7. The parking assistance method according to claim 1 or 2, characterized in that: The second target driving trajectory and the position of the vehicle are displayed on a display device that can be visually confirmed by the user of the vehicle.

8. The parking assistance method according to claim 1 or 2, characterized in that: The second target driving trajectory is calculated by connecting the starting parking position and the target intermediate position, and the target intermediate position and the target parking position respectively by a clothoid curve.

9. A parking assistance device, characterized in that: There is a controller that stores the actual trajectory of the vehicle moving from the starting point to the target parking position when the vehicle is parked manually as the actual driving trajectory, calculates the trajectory from the starting point to the target parking position, i.e., the first target driving trajectory, based on the relative position between the starting point and the target parking position of the actual driving trajectory, and calculates the range in the actual driving trajectory that deviates from the first target driving trajectory by more than a first specified distance, i.e., the deviation range. A certain location within the deviation range is set as the target intermediate position. When assisting the vehicle to park at the target parking position, the controller calculates the position of the vehicle at the moment of starting to park, i.e., the parking start position, and the trajectory from the parking start position, via the target intermediate position, to the target parking position, i.e., the second target driving trajectory, and performs parking assistance control to assist the vehicle to move along the second target driving trajectory. Set a point on the actual driving trajectory within the deviation range as the target intermediate position.

10. A parking assistance device, characterized in that: There is a controller that stores the actual trajectory of the vehicle moving from the starting point to the target parking position when the vehicle is parked manually as the actual driving trajectory, calculates the trajectory from the starting point to the target parking position, i.e., the first target driving trajectory, based on the relative position between the starting point and the target parking position of the actual driving trajectory, and calculates the range in the actual driving trajectory that deviates from the first target driving trajectory by more than a first specified distance, i.e., the deviation range. A certain location within the deviation range is set as the target intermediate position. When assisting the vehicle to park at the target parking position, the controller calculates the position of the vehicle at the moment of starting to park, i.e., the parking start position, and the trajectory from the parking start position, via the target intermediate position, to the target parking position, i.e., the second target driving trajectory, and performs parking assistance control to assist the vehicle to move along the second target driving trajectory. The controller performs the following control: (a1) Calculate the trajectory from the starting point, via the target intermediate position, to the target parking position. (b1) Determine whether the vehicle can move on the calculated trajectory. (c1) If it is determined that the vehicle cannot move on the calculated trajectory, reset the target intermediate position to another location within the deviation range. Repeat (a1) to (c1) until it is determined in (b1) that the vehicle can move on the calculated trajectory.

Images