JP2018065404A - Parking support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a target locus line which is estimated to be drawn by a vehicle and allow a vehicle to be parked in a parking frame smoothly, in entry of a vehicle to the parking frame.SOLUTION: A vehicle 2 is made to travel in a direction where an extension line of a center line CL1 of the vehicle 2 and an extension line of a center line CL2 of a parking frame W cross, and the vehicle 2 is made to be parked at a position where a centroid G of the vehicle 2 matches to the extension line of the center line CL2, and the extension line of the center line CL1 becomes parallel to the extension line of the center line CL2, by making right drive wheels 20FR, 20RR and left drive wheels 20FL, 20RL rotate in reverse rotation, for rotating the vehicle 2 with the centroid G as a center, and in a rotation step, deviation of the centroid G to the extension line of the center line CL2, and if the deviation is detected, rotation of the vehicle 2 with the centroid G as a center is stopped at a position where, a length B1 which is along the center line CL1 from a cross point A where the extension line of the center line CL1 and the extension line of the center line CL2 cross, and a length B2 which is along the center line CL2 from the cross point A are equal.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a parking assistance device.

  Conventionally, there has been proposed a parking control device that is effective when the road space ahead of the parking frame is narrow. The parking control device includes a drive system that selectively executes a normal travel mode and a super-revolution turn mode. The drive system includes an independent steering (steering device) for each wheel, and the driving force of each wheel is controlled independently. In the super-revolution turn mode of the parking control device, the super-revolution is performed in which the vehicle center is made coincident with the extension line of the center line of the parking frame and the vehicle is turned around the center of gravity of the vehicle. When the direction along the center line of the parking frame coincides with the direction along the center line of the vehicle, the supertrust turning mode ends, and parking in the normal driving mode (reverse in a straight-ahead steering state, etc.) (For example, refer to Patent Document 1)

International Publication No. 2012/137723

  By the way, the structure of the steering wheel provided independently for each wheel is very complicated, resulting in a significant cost increase. Here, there are vehicles having independent driving force for each wheel even if each wheel does not have independent steering. That is, this vehicle has an in-wheel motor that drives each wheel independently, and the driving force of each wheel is controlled independently. In the vehicle, rotation control on the spot is performed only by driving the left and right wheels in opposite directions. However, in this rotation control, not all wheels are steered, so the frictional resistance with the road surface is large, and the rotation center of the vehicle is on the extension line of the center line of the parking frame during the rotation control. It may shift. When the vehicle is stopped parallel to the extended line of the center line of the parking frame with the center of rotation shifted, in order to guide the vehicle from there to the center line of the parking frame, for example, after steering the steering to the right Need to steer left. That is, the target trajectory line assumed to be drawn by the vehicle is complicated when the vehicle enters the parking frame. In addition, when the distance between the vehicle and the parking frame is short, the target locus line may not be drawn.

  The present invention has been made in view of the above problems, and can simplify a target trajectory line assumed to be drawn by the vehicle when the vehicle enters the parking frame, and smoothly park the vehicle in the parking frame. An object of the present invention is to provide a parking assist device that can perform the above.

  The parking assist device according to the present invention can simplify the target locus line assumed to be drawn by the vehicle when the vehicle enters the parking frame, and can smoothly park the vehicle in the parking frame. is there.

  That is, the parking assist device according to the present invention is a parking assist device that sets a trajectory for guiding a vehicle having drive wheels that are driven independently by all wheels to a parking frame, and an extension line of the center line of the vehicle and the vehicle A vehicle travel control unit that causes the vehicle to travel in a direction intersecting with an extension line of the center line of the parking frame, and stops the vehicle at a position where the center of gravity of the vehicle coincides with the extension line of the center line of the parking frame; By rotating the right driving wheel and the left driving wheel of all the wheels in reverse so that the extension line of the center line of the vehicle is parallel to the extension line of the center line of the parking frame, the center of gravity is A vehicle rotation control unit that rotates the vehicle as a center, and a center-of-gravity shift detection unit that detects a shift of the center of gravity with respect to an extension line of the center line of the parking frame in the process of rotating the vehicle by the vehicle rotation control unit; Detection of center of gravity deviation When the shift of the center of gravity is detected by the above, the length along the center line of the vehicle from the intersection point where the extension line of the center line of the vehicle and the extension line of the center line of the parking frame intersect, A vehicle rotation stop control unit that stops the rotation around the center of gravity of the vehicle at a position where the length along the center line of the parking frame from the intersection to the parking frame is equal. And

  According to the parking assist device according to the present invention configured as described above, it is possible to simplify the target trajectory line assumed to be drawn by the vehicle when the vehicle enters the parking frame. As a result, the vehicle can be parked smoothly within the parking frame.

It is a functional block diagram which shows the function structure of the parking assistance apparatus which concerns on Example 1 of this invention. FIG. 2 is a hardware block diagram illustrating a specific device configuration of the parking assistance device according to the first embodiment. It is a figure explaining the outline | summary of the automatic parking performed by the parking assistance apparatus which concerns on Example 1 (the 1). It is a figure explaining the outline | summary of the automatic parking performed by the parking assistance apparatus which concerns on Example 1 (the 2). It is a figure explaining the outline | summary of the automatic parking performed by the parking assistance apparatus which concerns on Example 1 (the 3). It is a figure explaining the outline | summary of the automatic parking performed by the parking assistance apparatus which concerns on Example 1 (the 4). It is a figure explaining the outline | summary of the automatic parking performed by the parking assistance apparatus which concerns on Example 1 (the 5). It is a figure explaining the outline | summary of the automatic parking performed by the parking assistance apparatus which concerns on Example 1 (the 6). It is a figure explaining the two-wheel model which replaced the four-wheeled vehicle of Example 1 with the two-wheeled vehicle. It is a flowchart which shows the flow of the whole process performed with the parking assistance apparatus which concerns on Example 1. FIG.

  Hereinafter, specific embodiments of a parking assistance device according to the present invention will be described with reference to the drawings.

  In this embodiment, the parking assist device of the present invention is mounted on a vehicle to constitute a system that supports the parking operation of the vehicle.

(Description of the configuration of the embodiment)
First, the configuration of the present apparatus will be described with reference to FIGS. 1 and 2.

  The parking assistance apparatus 1 according to the present embodiment is installed in a vehicle 2 as shown in FIG. The parking assist device 1 includes an image conversion unit 10, a parking frame information detection unit 11, a control start SW detection unit 12, a control start determination unit 13, a road travel control unit 14 before the parking frame, and a parking frame front. Stop control unit 15, vehicle rotation control unit 16, center-of-gravity deviation detection unit 17, vehicle rotation stop control unit 18, rotation angle calculation unit 19, vehicle target locus line setting unit 21, vehicle target locus line travel control Unit 22 and vehicle stop control unit 23.

  The vehicle 2 is an automatic four-wheeled vehicle whose front wheels are steering wheels, and is a driving wheel that drives all four wheels independently. That is, the vehicle 2 is configured such that an in-wheel motor is provided for each wheel and the driving force of each motor is individually controlled.

  The image conversion unit 10 performs coordinate conversion on a plurality of images captured by the cameras 20b to 20e (FIG. 2), and generates an overhead view in which the vehicle 2 is looked down from above. The image conversion unit 10 synthesizes the generated plurality of overhead views around the virtual image representing the vehicle 2 to generate one overhead image. This overhead view image is displayed on the display 20f (FIG. 2). Note that a technique for generating such a bird's-eye view image is already known, for example, as proposed in Japanese Patent Laid-Open No. 5-79848, and detailed description thereof is omitted.

  The parking frame information detection unit 11 detects parking frame information regarding a parking frame in which the vehicle 2 is parked. For example, the parking frame information detection part 11 acquires the position where the vehicle is not parked as parking frame information among the parking frames drawn in the bird's-eye view image. A technique for detecting various types of information from a bird's-eye view image has already been well-known, for example, as proposed in Japanese Patent Laid-Open No. 5-79848, and detailed description thereof will be omitted.

  The control start SW detection unit 12 detects an operation of the system operation SW 30 b (FIG. 2) by the driver of the vehicle 2.

  The control start determination unit 13 determines whether the detection signal detected by the control start SW detection unit 12 is correct. The control start determination unit 13 determines that the detection signal is correct when the detection signal is not noise or the like. When the detection signal is correct, the control start determination unit 13 outputs a positive signal indicating that to the road travel control unit 14 in front of the parking frame.

  When a positive signal is received from the control start determination unit 13, the front parking frame road traveling control unit 14 controls the in-wheel motor 40 b (FIG. 2) based on the parking frame information detected by the parking frame information detection unit 11. Then, the vehicle 2 is caused to travel along the road ahead of the parking frame that is the road ahead of the parking frame.

  The parking frame stop control unit 15 controls the brake caliper 50b (FIG. 2) based on the parking frame information detected by the parking frame information detection unit 11, and stops the vehicle 2 on the road before the parking frame. The parking frame stop control unit 15 stops the vehicle 2 at a position where the center of gravity of the vehicle 2 coincides with the extended line of the center line of the parking frame on the road before the parking frame.

  The vehicle rotation control unit 16 controls the in-wheel motor 40 b (FIG. 2) based on the parking frame information detected by the parking frame information detection unit 11, so that the right drive wheel of the front, rear, left and right four wheels By rotating the left driving wheel in the reverse direction, the vehicle 2 is rotated about the center of gravity of the vehicle 2 (super turning).

  The center-of-gravity shift detection unit 17 detects the shift of the center of gravity of the vehicle 2 with respect to the extended line of the center line of the parking frame in the process in which the vehicle 2 rotates about the center of gravity. Detect based on.

  The vehicle rotation stop control unit 18 controls the in-wheel motor 40b (FIG. 2) based on the parking frame information detected by the parking frame information detection unit 11, thereby stopping the rotation around the center of gravity of the vehicle 2. Let

  The rotation angle calculation unit 19 calculates the rotation angle of the vehicle 2 based on the parking frame information detected by the parking frame information detection unit 11 when the vehicle 2 is in a state where the rotation about the center of gravity is stopped. .

  The vehicle target trajectory line setting unit 21 sets a target trajectory line that the vehicle 2 follows when the vehicle 2 is guided to the parking frame based on the parking frame information detected by the parking frame information detection unit 11.

  The vehicle target locus line travel control unit 22 controls the in-wheel motor 40 b (FIG. 2) and the power steering motor 60 b (FIG. 2), and moves the vehicle along the target locus line set by the vehicle target locus line setting unit 21. Run 2.

  The vehicle stop control unit 23 controls the brake caliper 50b (FIG. 2) and stops the vehicle 2 in a state where the vehicle 2 has entered the parking frame.

  FIG. 2 is a hardware block diagram illustrating hardware elements that constitute the parking assistance apparatus 1.

  As shown in FIG. 2, the parking assistance device 1 sends a control command to each control module included in the parking assistance device 1 connected to a CAN (Controller Area Network) bus 3 laid in the vehicle 2. It has an ECU (Electronic Control Unit) 20a, an ADAS (Advanced Driving Assistant System) ECU 30a, a wheel motor ECU 40a, a brake ECU 50a, and an electric power steering ECU 60a. Hereinafter, the electric power steering ECU 60a may be simply abbreviated as an electric power steering ECU 60a.

  The camera ECU 20a includes a front camera 20b (imaging unit) that images a front nearest area including the front end of the vehicle 2, a left camera 20c (imaging unit) that images a left nearest area including the left end of the vehicle, A rear camera 20d (imaging unit) that captures the rear closest region including the rear end and a right camera 20e (imaging unit) that captures the right immediate region including the right end of the vehicle are connected to each other. The camera ECU 20a controls the imaging operation of these cameras 20b to 20e.

  The camera ECU 20a is further connected to a display 20f for the driver of the vehicle 2 to check the operation status of the parking assist device 1. The display 20f is installed at a position where the driver can visually recognize, and displays an overhead view generated by the image conversion unit 10 (FIG. 1). The display 20f has a touch panel function, and the driver can input the pressed position coordinates by pressing a predetermined position on the display 20f. In addition, an operation menu of the parking assistance device 1 is displayed on the display 20f as appropriate, and the driver gives necessary instructions such as specifying a target parking position and inputting a parking method each time.

  The ADAS ECU 30a has a system operation SW 30b for instructing the start of parking assistance provided at a position where the driver of the vehicle 2 can easily operate, and when the parking assistance function is stopped due to an unexpected obstacle entry, A control stop buzzer 30c for notifying the driver of the fact is connected to each. The ADAS ECU 30 a governs the overall operation of the parking assist device 1.

  The wheel motor ECU 40a is connected to an in-wheel motor 40b provided on each drive wheel of the vehicle 2, and controls the rotation direction and the rotation amount of the in-wheel motor 40b when performing a parking operation. The movement control is performed.

  A brake caliper 50b provided on each drive wheel of the vehicle 2 is connected to the brake ECU 50a, and the braking force of the vehicle 2 is controlled.

  A power steering motor 60b is connected to the electric power steering ECU 60a, and the steering control of the vehicle 2 is performed by controlling the direction and amount of rotation of the power steering motor 60b when performing a parking operation.

(Description of automatic parking overview)
Hereinafter, the outline of the operation performed in the parking assistance device 1 will be described in order with reference to FIGS. 3 to 8, the images respectively captured by the cameras 20 b to 20 e (FIG. 2) installed in the vehicle 2 are coordinate-converted by the image conversion unit 10 (FIG. 1) as seen from above. This is an example in which a single overhead image is synthesized.

  As shown in FIGS. 3 to 8, for example, images captured by the cameras 20 b to 20 e are synthesized around the current position of the vehicle 2 created by CG. Hereinafter, this image is referred to as a surrounding map I. This coordinate conversion and composition is started, for example, with the ON operation of the system operation SW 30b (FIG. 2), and thereafter continuously executed at a predetermined time interval. The synthesized surrounding map I is displayed as needed. 20f (FIG. 2). In the present embodiment, the vehicle 2 is parked at the target parking position S1 shown in FIGS.

(Description of lane markings indicating parking frames)
First, a lane marking indicating a parking frame will be described with reference to FIG.

  As shown in FIG. 3, the parking frame constituting the target parking position S <b> 1 in which the parking assistance device 1 operates is configured by a lane marking drawn on the road surface with a white line or a yellow line, for example. FIG. 3 is an example of a lane marking Wi drawn so as to define the left and right of the target parking position S1. The vehicle 2 is parked with respect to the target parking position S1 on which the lane marking Wi is drawn.

(Description of how to specify the target parking position)
Next, a method for specifying the target parking position S1 when the parking assist device 1 is operated will be described with reference to FIG.

  The driver of the vehicle 2 stops the vehicle 2 and specifies the target parking position S1 while confirming the surrounding map I displayed on the display 20f (FIG. 2). Specifically, the driver of the vehicle 2 moves the vehicle 2 to a position where the target parking position S1 that the user wants to park is reflected in the surrounding map I displayed on the display 20f. Stop. Thereafter, the user touches the target parking position S1 (one point inside the parking frame) in the display 20f with a finger, and inputs the coordinates of the target parking position S1.

  Information indicating the coordinates of the input target parking position S1 is transmitted to the parking frame information detection unit 11 (FIG. 1). The parking frame information detection unit 11 detects a marking line Wi that defines a parking frame including the target parking position S1.

  The lane marking Wi is detected, for example, by capturing an image including the coordinates of the target parking position S1 among the four cameras (front camera 20b, left camera 20c, rear camera 20d, and right camera 20e) constituting the imaging unit. This is performed on an image picked up by the camera to be selected.

  The detection of white lines and yellow lines drawn on the road surface by image processing is generally performed nowadays, and any of these methods may be used.

  For example, a lane marking composed of white lines or yellow lines drawn on a road surface is generally brightly imaged with respect to the road surface. Therefore, a point (pixel) having a positive luminance difference with respect to the road surface is detected, and an area surrounded by the detected point and having a predetermined width is detected as an area representing a lane marking. do it. In addition, according to this method, dirt or dirt on the road surface may be detected. Therefore, after detecting a corresponding point, a constraint condition such that a plurality of detected points form a straight line is set. It is preferable to apply and select a region representing a lane marking.

(Explanation of the travel control method in the parking lane front road)
After the setting of the target parking position S1 is completed, the driver designates a parking method. Specifically, a parking method to be performed is selected from a menu for selecting a parking method displayed on the display 20f. In the present embodiment, it is assumed that the parallel parking is selected by retreating.

  When the parking method is selected, next, the parking in front of the parking frame W including the target parking position S1, as shown in FIG. A target movement locus of the vehicle 2 on the front frame lane R1 is calculated.

Parked car frame preceding vehicle road travel control unit 14, the target moves and the center of gravity G of the center line CL1 of the vehicle 2 bisects, the extension line of the center line CL2 of the parking space W between the intersection P1 which crosses the path connecting the Calculate as a route. The center line CL1 is a line segment having the position B of the front camera 20b and the position C of the rear camera 20d as both ends. The center line CL2 passes through the point D that bisects the line segment K having the end points K1 and K2 at both ends of the two left and right dividing lines Wi on the side on which the vehicle 2 enters, and is perpendicular to the line segment K. It is a line segment.

  Information necessary for calculating the target movement route is read out as needed from the coordinates on the surrounding map I as parking frame information and used.

  The parking frame front road travel control unit 14 controls the in-wheel motor 40b (FIG. 2) to cause the vehicle 2 to travel forward toward the intersection P1 along the target movement route. That is, the parking frame front road travel controller 14 rotates the right front wheel 20FR and the right rear wheel 20RR, and the left front wheel 20FL and the left rear wheel 20RL in the same direction, as indicated by the broken lines in FIG. Until the center of gravity G of the vehicle 2 coincides with the extended line of the center line CL2 of the parking frame W, the direction indicated by the white arrow in FIG. 3, that is, the extended line of the center line CL1 of the vehicle 2 and the parking frame W The vehicle 2 is moved in a direction intersecting with the extended line of the center line CL2.

  Hereinafter, when it is not necessary to specify the positions of the right front wheel 20FR, the right rear wheel 20RR, the left front wheel 20FL, and the left rear wheel 20RL, they are simply referred to as drive wheels 20.

(Explanation of the travel stop control method in the parking lane front road)
Even while the parking frame front road travel control unit 14 is performing the travel control on the parking frame front road, the center of gravity G of the vehicle 2 is at the center line CL2 of the parking frame W at any time in the camera ECU 20a (FIG. 1). Whether or not the extension line is matched is detected using the camera image.

  When the coincidence is detected, the parking frame stop control unit 15 then operates the brake caliper 50b (FIG. 2) to stop the vehicle 2 on the parking frame front road R1 as shown in FIG. Let

  Information necessary for the travel stop control is read out as needed from the coordinates on the surrounding map I as parking frame information and used.

(Explanation of vehicle rotation control method in front of parking frame)
Whether or not the vehicle 2 has stopped on the lane R1 in front of the parking frame is detected at any time using the camera image by the camera ECU 20a (FIG. 2).

  When the stop is detected, the in-wheel motor 40b (FIG. 2) is then controlled in the vehicle rotation control unit 16, and the vehicle 2 rotates in the direction of the arrow shown in white in FIG. Control is performed. That is, the vehicle rotation control unit 16 causes the right front wheel 20FR and the right rear wheel 20RR, the left front wheel 20FL, and the left rear wheel so that the center line CL1 of the vehicle 2 is parallel to the extension line of the center line CL2 of the parking frame W. The vehicle 2 is rotated on the spot around the center of gravity G of the vehicle 2 by rotating the 20RL in reverse. In this embodiment, the left front wheel 20FL and the left rear wheel 20RL are rotated forward, and the right front wheel 20FR and the right rear wheel 20RR are rotated backward to rotate the vehicle 2 clockwise.

  Information necessary for vehicle rotation control is read out as needed from the coordinates on the surrounding map I as parking frame information and used.

(Explanation of center of gravity deviation detection method)
In the vehicle 2, on-site rotation control is performed only by driving the right front wheel 20FR and the right rear wheel 20RR, and the left front wheel 20FL and the left rear wheel 20RL in the reverse direction. However, in this rotation control, not all the drive wheels 20 are steered, so the frictional resistance with the road surface is large, and the center of gravity G of the vehicle 2 is the center line of the parking frame W during the rotation control. It may deviate from the extension line of CL2. For example, as shown in FIG. 5, the position of the center of gravity G gradually changes from the point P1 to the point P2.

  As shown in FIG. 5, with the center of gravity G shifted, the camera ECU 20a (FIG. 2) continues to detect the length of the line segment B1 and the length of the line segment B2. If there is no deviation of the center of gravity G, the extension line of the center line CL2 of the parking frame W coincides with the center line CL1 of the vehicle 2 when the rotation control is finished. If the vehicle 2 is moved backward as it is, it can be guided to the parking frame W.

  However, when the rotation control is finished in a state where the center of gravity G is shifted, in this case, the extension line of the center line CL2 of the parking frame W and the center line CL1 of the vehicle 2 are in parallel. If the vehicle 2 is guided to the parking frame W in the parallel state, the target locus line assumed to be drawn by the vehicle 2 becomes an S-shaped curve and becomes complicated. In this respect, the present embodiment performs the following control in order to guide the vehicle 2 to the parking frame W by only one steering, instead of drawing an S-shaped curve.

  In the process in which the vehicle 2 is rotated around the center of gravity G by the vehicle rotation control unit 16, the center of gravity deviation detection unit 17 detects the deviation of the center of gravity G of the vehicle 2 from the extension line of the center line CL 2 of the parking frame W.

  Specifically, the line segment B1 connects the right rear wheel 20RR and the left rear wheel 20RL from the intersection A where the extension line of the center line CL1 of the vehicle 2 and the extension line of the center line CL2 of the parking frame W intersect. It is a line segment that extends along the center line CL1 of the vehicle 2 up to the center position F of the axle. The line segment B2 is a line segment extending along the center line CL2 of the parking frame W from the intersection point A to the point D.

(Explanation of vehicle rotation stop control method in the road ahead of the parking frame)
When the deviation of the center of gravity G is detected by the center-of-gravity deviation detection unit 17, the in-wheel motor 40b (FIG. 2) is controlled by the vehicle rotation stop control unit 18 (FIG. 1), and the vehicle 2 is as shown in FIG. Stop rotation in posture. That is, the vehicle rotation stop control unit 18 temporarily stops the rotation about the center of gravity G of the vehicle 2 at a position where the length of the line segment B1 is equal to the length of the line segment B2, as shown in FIG. . As shown in FIG. 6, the length of the line segment B1 is the sum of the length of the line segment B0 and the length of the line segment B3. As shown in FIG. 6, the line segment B0 is a line segment having the intersection A and the position C of the rear camera 20d as both ends. As shown in FIG. 6, the line segment B3 is a length along the center line CL1 of the vehicle 2 from the center position F of the axle connecting the right rear wheel 20RR and the left rear wheel 20RL to the position C of the rear camera 20d. This is a line segment having (offset value).

(Explanation of tire angle calculation method)
Whether the vehicle 2 has stopped rotating is detected by the camera ECU 20a (FIG. 2) at any time using the camera image.

  When the stop is detected, the rotation angle calculation unit 19 calculates the tire angle δ to be steered from now on. That is, as shown in FIG. 6, the rotation angle calculation unit 19 calculates the tire angle δ of the vehicle 2 to be steered from when the vehicle 2 is stopped from rotating about the center of gravity G.

Specifically, the rotation angle calculation unit 19 calculates the tire angle δ using the following equation (1) based on a two-wheel model in which a four-wheel vehicle is replaced with a two-wheel vehicle as shown in FIG.

  Here, L is a wheel base of the vehicle 2. As shown in FIG. 6, the wheel base L has an axle center position E connecting the right front wheel 20FR and the left front wheel 20FL and an axle center position F connecting the right rear wheel 20RR and the left rear wheel 20RL at both ends. Is a line segment. R is a radius of a circle having the line segment B1 and the line segment B2 as two tangent lines.

  Information necessary for calculating the tire angle δ is read and used as parking frame information from the coordinates on the surrounding map I by the rotation angle calculation unit 19 as necessary.

(Explanation of target track line setting method)
Information indicating the tire angle δ calculated by the rotation angle calculation unit 19 is transmitted to the vehicle target locus line setting unit 21 (FIG. 1).

  When the information is received, the vehicle target trajectory line setting unit 21 uses the information indicating the tire angle δ to set a target trajectory line M that the vehicle 2 follows when the vehicle 2 is guided to the parking frame W. That is, the vehicle target trajectory line setting unit 21 sets, as the target trajectory line M, an arc having two tangents to the line segment B1 and the line segment B2, as shown in FIG. The target trajectory line M draws a monotonous arc from the center position F of the axle connecting the right rear wheel 20RR and the left rear wheel 20RL to the point D, as shown in FIG. Thereby, the target locus line M assumed to be drawn by the vehicle 2 when the vehicle 2 enters the parking frame W can be simplified.

  Note that the tangent information of the line segment B1 and the line segment B2 necessary for setting the target trajectory line M is read as needed from the coordinates on the surrounding map I as parking frame information and used.

  When the target trajectory line M is set, the vehicle target trajectory line travel control unit 22 (FIG. 1) moves the vehicle 2 along the target trajectory line M. That is, the vehicle target locus line travel control unit 22 calculates the tire angle calculated by the rotation angle calculation unit 19 for the steerable right front wheel 20FR and the left front wheel 20FL among all the drive wheels 20, as shown in FIG. Steer based on δ. Specifically, in the vehicle target locus line travel control unit 22, the power steering motor 60b (FIG. 2) is controlled, and the right front wheel 20FR and the left front wheel 20FL are steered leftward as shown in FIG.

  Following this steering, the vehicle target trajectory line travel control unit 22 controls the in-wheel motor 40b (FIG. 2) to direct all the drive wheels 20 in the same direction along the target trajectory line M. Run backwards. That is, the vehicle target trajectory line travel control unit 22 rotates the right front wheel 20FR and the right rear wheel 20RR, and the left front wheel 20FL and the left rear wheel 20RL in the same direction, as shown in FIG. The vehicle 2 is moved until the extension line of the center line CL1 coincides with the extension line of the center line CL2 of the parking frame W. In this state, the center position F of the axle connecting the right rear wheel 20RR and the left rear wheel 20RL coincides with the point D as shown in FIG.

  Although not shown in FIG. 7, in the state after the movement, the vehicle target trajectory line travel control unit 22 controls the power steering motor 60b (FIG. 2) so that the right front wheel 20FR and the left front wheel 20FL go straight ahead. The vehicle is steered to a state and returned to a direction parallel to the center line CL1 of the vehicle 2 as shown in FIG.

(Description of the vehicle stop control method at the target parking position)
In the camera ECU 20a (FIG. 2), the vehicle target locus line travel control unit 22 detects whether the vehicle 2 has reached the target parking position S1 as needed.

  When it is detected that the vehicle has arrived, the vehicle stop control unit 23 stops the vehicle 2 at the target parking position S1. That is, as shown in FIG. 8, the vehicle stop control unit 23 is equal to the line segment K having both ends of the end points K1 and K2 of the two left and right dividing lines Wi on the side on which the vehicle 2 enters and the width of the vehicle 2. The vehicle 2 is stopped at the target parking position S1 based on the positional relationship with the line segment H that has a length and is in contact with the position B of the front camera 20b.

  Specifically, as shown in FIG. 8, when the position B of the front camera 20b straddles the line segment K and further enters the parking frame W by a predetermined distance, the camera ECU 20a (FIG. 2) It is determined that the parallel parking to W is completed, and the vehicle stop control unit 23 operates the brake caliper 50b (FIG. 2) to stop the vehicle 2.

  Information necessary for the vehicle stop control at the target parking position is read out from the coordinates on the surrounding map I as parking frame information as needed.

(Description of the flow of processing in the embodiment)
The outline of the process performed in the parking support apparatus 1 has been described above. Next, the overall process flow will be described with reference to the flowchart of FIG.

  (Step S10) The vehicle 2 traveling control unit 14 (FIG. 1) performs straight traveling control of the vehicle 2 on the parking frame front road R1 (FIG. 3).

  (Step S11) In the camera ECU 20a (FIG. 2), it is detected whether or not the center of gravity G of the vehicle 2 matches the extension line of the center line CL2 of the parking frame W. When the match is detected, the process proceeds to step S12. When the match is not detected, step S10 is repeated.

  (Step S12) The stop control of the vehicle 2 is performed in the parking frame stop control unit 15 (FIG. 1). Following this stop control, the vehicle rotation control unit 16 (FIG. 1) performs rotation control of the vehicle 2 on the spot with the center of gravity G of the vehicle 2 as the center.

  (Step S13) In the camera ECU 20a (FIG. 2), it is detected whether or not the center of gravity G of the vehicle 2 is on an extension line of the center line CL2 of the parking frame W. When it is detected that the center of gravity G is on the extension line of the center line CL2, the process proceeds to step S14. When it is not detected that the center of gravity G is on the extension line of the center line CL2, that is, the position of the center of gravity G is an extension of the center line CL2. When it deviates from a line, it progresses to Step S17.

  (Step S14) In the camera ECU 20a (FIG. 2), it is detected whether or not the extension line of the center line CL1 of the vehicle 2 matches the extension line of the center line CL2 of the parking frame W. When the match is detected, the process proceeds to step S15. When the match is not detected, the process proceeds to step S12.

  (Step S15) In the vehicle rotation stop control unit 18 (FIG. 1), the rotation of the vehicle 2 around the center of gravity G of the vehicle 2 is stopped. When there is no left-right difference in road friction resistance, the position of the center of gravity G of the vehicle 2 does not move. At this time, since the extension line of the center line CL1 of the vehicle 2 coincides with the extension line of the center line CL2 of the parking frame W, the stop control of the vehicle 2 may be performed on the spot.

  (Step S16) In the vehicle target locus line setting unit 21 (FIG. 1), a target locus line for causing the vehicle 2 to travel backward toward the parking frame W is set.

  (Step S17) In the camera ECU 20a (FIG. 2), it is detected whether or not the length of the line segment B1 (FIG. 6) matches the length of the line segment B2 (FIG. 6). When the coincidence is detected, the process proceeds to step S18. When the coincidence is not detected, step S12 is repeated.

  (Step S18) In the vehicle rotation stop control unit 18 (FIG. 1), the rotation of the vehicle 2 around the center of gravity G of the vehicle 2 is stopped.

  (Step S19) In the vehicle target locus line setting unit 21 (FIG. 1), a target locus line M (FIG. 6) for causing the vehicle 2 to travel backward toward the parking frame W is set.

  (Step S20) In the vehicle target locus line travel control unit 22 (FIG. 1), traveling control of the vehicle 2 along the target locus line M (FIG. 6) is performed.

  (Step S21) In the camera ECU 20a (FIG. 2), it is detected whether or not the position of the vehicle 2 matches the target parking position S1 (FIG. 8). When the coincidence is detected, the process proceeds to step S22. When the coincidence is not detected, step S20 is repeated.

  (Step S22) In the vehicle stop control unit 23 (FIG. 1), stop control of the vehicle 2 is performed at the target parking position S1.

  As described above, according to the parking assist device 1 of the first embodiment configured as described above, when the shift of the center of gravity G is detected by the center of gravity shift detection unit 17, the vehicle rotation stop control unit 18 performs the in-wheel operation. The motor 40b (FIG. 2) is controlled, and the vehicle 2 stops rotating in a posture as shown in FIG. That is, the vehicle rotation stop control unit 18 temporarily stops the rotation about the center of gravity G of the vehicle 2 at a position where the length of the line segment B1 is equal to the length of the line segment B2, as shown in FIG. .

  For this reason, in the process of rotating the vehicle 2 on the spot, even if the position of the center of gravity G of the vehicle 2 changes due to the difference between the left and right road surface friction resistances, automatic parking control is performed after the rotation control by the vehicle rotation control unit 16 ends. When performing, the vehicle 2 can be stopped at the target parking position S1 only by operating the steering direction in one direction toward the target parking position S1.

  That is, when the automatic parking control is performed, as shown in FIG. 6, the right front wheel 20FR and the left front wheel 20FL are steered leftward in the vehicle target locus line travel control unit 22. Following this steering, the vehicle target locus line travel control unit 22 performs the backward traveling of the vehicle 2 with all the drive wheels 20 directed in the same direction along the target locus line M. In the state after the reverse travel, the vehicle target trajectory line travel control unit 22 steers the right front wheel 20FR and the left front wheel 20FL straightly and returns them to a direction parallel to the center line CL1 of the vehicle 2 as shown in FIG. It is.

  According to the parking assist device 1 of the first embodiment configured as described above, the right front wheel 20FR and the left front wheel 20FL are steered to the left, and then steered straight and in a direction parallel to the center line CL1 of the vehicle 2. The vehicle 2 can be guided to the target parking position S1 only by returning the control. That is, the vehicle 2 can be guided to the target parking position S1 only by performing two-stage control including one steering and one return. Thereby, the target locus line M assumed to be drawn by the vehicle 2 when the vehicle 2 enters the parking frame W can be simplified. As a result, the vehicle 2 can be smoothly parked at the target parking position S1 in the parking frame W.

  In the first embodiment, an example in which the parking assist device of the present invention is applied to a vehicle is shown. However, the parking assist apparatus of the present invention can be similarly applied to a moving body (for example, an electric wheelchair or the like) including a steering wheel, a steering mechanism, and a drive system thereof.

  Furthermore, in Example 1, the example which stops the vehicle 2 in the parking frame which has the division line Wi drawn so that the right and left of target parking position S1 may be prescribed | regulated was shown. However, it is not limited to this. For example, a parking frame having a lane line drawn so as to surround the four sides of the target parking position S1, a parking frame having a lane line drawn to define the left and right of the target parking position S1, and the front or rear, The vehicle 2 may be stopped at a parking frame having lane lines drawn so as to define the front and rear of the parking position and the left or right side. In addition, for example, the vehicle 2 may be stopped in a parking frame on which no lane marking that defines the target parking position is drawn.

  Furthermore, in the first embodiment, an example is shown in which the center line CL1 of the vehicle 2 is configured by line segments having both ends of the position B of the front camera 20b and the position C of the rear camera 20d. However, it is not limited to this. For example, as shown in FIG. 6, a line segment having both ends at the center position E of the axle connecting the right front wheel 20FR and the left front wheel 20FL and the center position F of the axle connecting the right rear wheel 20RR and the left rear wheel 20RL. Thus, the center line CL1 of the vehicle 2 may be configured.

  Further, in the first embodiment, the point at which the target trajectory line M ends at the point D that bisects the line segment K having the end points K1 and K2 at both ends of the left and right lane markings Wi on the vehicle 2 approach side. An example of setting is shown. However, it is not limited to this. For example, points such as the vicinity of the center of the parking frame or the rear end of the parking frame may be set as points where the target locus line M ends.

  Furthermore, in Example 1, the parking frame information detection part 11 showed the example which detects parking frame information from the bird's-eye view image which converted the image imaged by the imaging part. However, it is not limited to this. For example, parking frame information may be detected using a sensor that can perform three-dimensional measurement such as a laser sensor, or parking frame information may be detected using GPS (Global Positioning System) data.

  As mentioned above, although the Example of this invention was explained in full detail with drawing, since an Example is only an illustration of this invention, this invention is not limited only to the structure of an Example. Of course, changes in design and the like within a range not departing from the gist are included in the present invention.

DESCRIPTION OF SYMBOLS 1 ... Parking assistance apparatus 2 ... Vehicle 10 ... Image conversion part 11 ... Parking frame information detection part 14 ... Parking frame front road travel control part (vehicle travel control part)
15 ... Parking frame stop control unit (vehicle running control unit)
16 ... Vehicle rotation control unit 17 ... Center of gravity deviation detection unit 18 ... Vehicle rotation stop control unit 19 ... Rotation angle calculation unit 20 ... Drive wheel 20FL ... Left front wheel (steering wheel)
20FR ... Right front wheel (steering wheel)
20RL ... Left rear wheel 20RR ... Right rear wheel 20b ... Front camera (imaging unit)
20c ... Left camera (imaging unit)
20d: Rear camera (imaging unit)
20e ... Right camera (imaging part)
22 ... Vehicle target locus line travel control unit (vehicle travel control unit)
23 ... Vehicle stop control unit (vehicle travel control unit)
B0, B1, B2, B3 ... line segments CL1, CL2 ... center line G ... center of gravity L ... wheel base P1 ... intersection W ... parking frame delta ... tire angle (rotation) Corner)

Claims (3)

A parking assist device for setting a trajectory that guides a vehicle having driving wheels that all wheels independently drive to a parking frame,
The vehicle is driven in a direction in which an extension line of the center line of the vehicle and an extension line of the center line of the parking frame intersect, and the center of gravity of the vehicle coincides with the extension line of the center line of the parking frame. A vehicle travel control unit for stopping the vehicle;
By rotating the right driving wheel and the left driving wheel of all the wheels in reverse so that the extension line of the center line of the vehicle is parallel to the extension line of the center line of the parking frame, the center of gravity is A vehicle rotation control unit that rotates the vehicle as a center;
In the course of rotation of the vehicle by the vehicle rotation control unit, a center-of-gravity shift detection unit that detects a shift of the center of gravity with respect to an extension line of the center line of the parking frame;
When the deviation of the center of gravity is detected by the center-of-gravity deviation detection unit, the center line of the vehicle from the intersection where the extension line of the center line of the vehicle intersects with the extension line of the center line of the parking frame to the vehicle. A vehicle rotation stop control unit that stops rotation around the center of gravity of the vehicle at a position where the length along the center line of the parking frame from the intersection to the parking frame is equal. A parking assistance device characterized by comprising: When the vehicle stops rotating around the center of gravity, a line segment having a length along the center line of the vehicle from the intersection to the vehicle, and from the intersection to the parking frame A rotation angle calculation unit for calculating a rotation angle of the vehicle based on a radius of a circle having two tangent lines having a length along the center line of the parking frame and a wheel base of the vehicle Have
The vehicle rotation control unit steers steerable steering wheels among all the wheels based on the rotation angle calculated by the rotation angle calculation unit, and in the state where the steering wheel is steered, 2. The vehicle according to claim 1, wherein the vehicle is moved to a state in which an extension line of the center line of the vehicle coincides with an extension line of the center line of the parking frame by rotating the left driving wheel in the same direction. The parking assistance device described. An imaging unit for imaging the periphery of the vehicle;
An image conversion unit that converts an image obtained by imaging by the imaging unit into an overhead image,
The parking frame information related to the parking frame acquired from the overhead image includes information indicating a length along the center line of the vehicle from the intersection to the vehicle, and the parking from the intersection to the parking frame. The parking assistance device according to claim 1 or 2, wherein at least information indicating a length along a center line of the frame is included.