JP2010269707A - Parking assist system of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of assisting parking capable of automatically parking a vehicle in a parking space by one or more turnabouts while reducing a calculation load and avoiding a cost increase. <P>SOLUTION: The system for parking by automatic steering detects the width of the parking space and the width of a road facing the parking space. A parking route table 41 in which a parking route for parking the vehicle in the parking space by one turnabout and a parking route for parking the vehicle in the parking space by a plurality of turnabouts are defined in advance in accordance with the width of the parking space and the width of the road facing the parking space. Candidate parking routes are read from the parking route table 41 based on the widths of the detected parking space and road. One of the read candidate parking routes is selected based on a vehicle position which is specified when the vehicle is stopped for parking. The steering of the vehicle is driven so that the vehicle is guided following the selected parking route. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a system for assisting parking of a vehicle in a parking space.

  Conventionally, a parking assist device by automatic steering of a vehicle has been proposed. According to this device, the vehicle can be parked in a desired parking space by automatic steering. For example, Patent Document 1 below discloses an automatic parking control device that can automatically park in a parking space even when the width of a road in front of the parking space is narrow.

JP 2008-179345 A

  Many conventional parking assistance devices are based on the premise that a vehicle is parked in a parking space by only one turnover. If the width of the road facing the parking space is narrow, it is difficult to park the vehicle in the parking space with only one turn.

  Moreover, in said patent document 1, parking control is performed by predicting the driving | running | working locus of a vehicle in real time using sensors, such as a radar, in front of a parking space. However, always predicting the travel locus is computationally expensive and requires a relatively expensive computing device. In addition, the use of radar also increases costs.

  Therefore, an object of the present invention is to provide a parking support capable of automatically parking a vehicle in a parking space by not only one turnover but also a plurality of turnovers while reducing calculation load and avoiding an increase in cost. Is to provide a method.

  According to one aspect of the present invention, a parking assistance system for parking a vehicle in a parking space by automatic steering detects a width of the parking space and a width of a road facing the parking space. Means for identifying the position of the vehicle relative to the parking space, a parking path for parking in the parking space by one turn-back, and a parking path for parking in the parking space by a plurality of turn-backs. And a parking route table defined in advance according to the width of the road facing the parking space, and means for reading the parking route candidates from the parking route table based on the detected width of the parking space and the width of the road And the position of the vehicle specified by the position specifying means when the vehicle stops for parking Based on provided selection means for selecting one of the candidate of the read parking path, to direct the vehicle in accordance with the selected parking path, and driving means for driving the wheel of the vehicle, a.

  According to the present invention, since the parking route to be parked in the parking space by one turn and a plurality of turns is defined in the parking route table in advance, it is not necessary to predict the travel locus of the vehicle in real time, and the calculation load is reduced. And cost can be reduced. In addition, the parking route table defines not only one turnover but also a parking route to be parked by multiple turns, so even if the road facing the parking space is narrow, parking by automatic steering is realized. can do. Furthermore, based on the position of the vehicle specified when the vehicle stops for parking, it is possible to accurately determine which parking route to guide the vehicle.

  According to an embodiment of the present invention, for each of the read parking path candidates, the position of the vehicle specified by the position specifying means when the vehicle stops for parking is the position of the read parking path. Means for determining whether or not the vehicle is ahead of the direction of travel of the vehicle relative to the position where the turning is completed toward the first turn-back position defined by the candidate, and the selection means includes at least the vehicle For the parking route starting from the route proceeding in the forward direction, the parking route determined to be in front of the vehicle in the traveling direction is selected from the read parking route candidates.

  According to this invention, at least for the parking route starting from the forward direction, the parking route is selected according to the determination result of whether or not the host vehicle is ahead of the position where the steering toward the first turn-back position is completed. Therefore, the vehicle can be guided more accurately on the parking route.

  According to an embodiment of the present invention, further, means for driving the steering of the vehicle so as to guide the vehicle to a position where the turning is started toward the first turn-back position defined by the selected parking route. Is provided.

  According to this invention, even when the vehicle is located at a location outside the selected parking route, the vehicle can be automatically guided on the selected parking route. Further, since such automatic guidance is performed, there is no need to separately define a route for guiding the vehicle from a location deviating from the selected route to the selected route.

  According to one embodiment of the present invention, the display means for displaying the area on the road through which the vehicle parks based on the selected parking route, and the display of the area on the road An input means for causing the occupant to input a decision as to whether or not to start the automatic steering, and the drive means receives a decision to start the automatic steering via the input means by the occupant And initiating guidance of the vehicle according to the selected parking route.

  According to this invention, since the area on the road through which the vehicle passes during parking is displayed to the occupant, the occupant starts automatic steering after determining whether there is an obstacle in the area on the road. be able to. Therefore, the driver can recognize that parking by automatic steering can be performed safely. Also, no special obstacle detection device is required for parking.

  According to an embodiment of the present invention, the means for detecting the width of the parking space and the means for detecting the width of the road are when the vehicle is traveling on the road facing the parking space toward the parking space. In addition, the width of the parking space and the width of the road are detected. Thus, when the vehicle is traveling toward the parking space, it is possible to automatically detect these widths and select an appropriate parking route.

  Other features and advantages of the present invention will be apparent from the detailed description that follows.

The figure which shows the whole structure of the parking assistance system mounted in the vehicle according to one Example of this invention. The functional block diagram of the control apparatus for parking assistance according to one Example of this invention. The figure for demonstrating the method to detect the width of the parking space and the width of the road according to one Example of this invention. The figure for demonstrating the coordinate system according to one Example of this invention. The figure which shows the table which prescribed | regulated the aspect of the parking mode parked by one turn back, and the parking path | route of this parking mode according to one Example of this invention. The figure which shows the table which prescribed | regulated the aspect of the parking mode which turns and stops the head part of a vehicle according to one Example of this invention, and parks in three turns, and the parking route of this parking mode. The figure which shows the table which prescribed | regulated the aspect of the parking mode which parks a vehicle substantially parallel to the entrance of a parking space according to one Example of this invention, and parks by turning back twice, and the parking route of this parking mode. The figure which shows an example of the display for inputting the determination of the start of automatic steering according to one Example of this invention. 1 is a flowchart of an automatic parking assistance process according to one embodiment of the present invention. The flowchart of the parking permission determination process according to one Example of this invention. The flowchart of the parking route determination process according to one Example of this invention. The flowchart of the parking route determination process according to one Example of this invention. The flowchart of the parking control process according to one Example of this invention. The flowchart of the parking control process according to one Example of this invention. The flowchart of the advance width-shifting control process according to one Example of this invention. The figure for demonstrating the outline | summary of advance width-shifting control according to one Example of this invention. The flowchart of the retreating and shifting control process according to one Example of this invention. 5 is a flowchart of a forward right turn control process according to an embodiment of the present invention. The figure for demonstrating the outline | summary of forward right turn control according to one Example of this invention. The flowchart of the reverse left turn control process according to one Example of this invention. The figure for demonstrating the outline | summary of reverse left turn control according to one Example of this invention.

  Next, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an overall configuration of a vehicle and its parking assist system according to an embodiment of the present invention.

  The vehicle V includes a steering wheel 1, a steering shaft 2, a steering actuator 3 having an electric motor that rotationally drives the steering shaft 2, a steering angle sensor 4 that detects a rotation angle (steering angle) of the steering shaft 2, and An electronic control unit (referred to as ECU) 5 is provided. The ECU 5 is a computer including a central processing unit (CPU) and a memory.

  The ECU 5 is connected to a brake actuator 9 that operates a brake and a shift actuator 10 that changes a shift lever of the automatic transmission. A shift position sensor 6 for detecting the shift lever position of the automatic transmission is provided, and a detection signal from the sensor is supplied to the ECU 5. A left wheel speed sensor 7 for detecting the left wheel speed and a right wheel speed sensor 8 for detecting the right wheel speed are provided in the vicinity of the left and right rear wheels. A pulse (hereinafter referred to as a wheel speed pulse) is output. The ECU 5 can detect the rotational distance of each wheel and the rotational direction (forward or reverse) of the wheel based on the received wheel speed pulse.

  Furthermore, cameras 11F and 11R that acquire front and rear images of the vehicle are provided at the front center and the rear center of the vehicle V, respectively. Left and right in front of the vehicle are provided with a sonar 13R capable of measuring the distance to the object existing in the right front area of the vehicle and 13L capable of measuring the distance to the object existing in the left front area of the vehicle. Yes. Signals from the cameras 11F and 11R and the sonars 13R and 13L are supplied to the ECU 5.

  The vehicle V is provided with a display device 15 so that the driver can visually recognize the vehicle. The ECU 5 can display images acquired by the cameras 11F and 11R on the display device 15. Further, the ECU 5 can notify the occupant via the display on the display device 15. Further, the display screen of the display device 15 constitutes a touch panel, and input data from the occupant can be supplied to the ECU 5. The vehicle V is provided with a speaker 16, and the ECU 5 can notify the occupant by sound or voice via the speaker 16.

  The ECU 5 recognizes the situation around the vehicle based on the signals supplied from the sensors, the camera and the sonar, controls the steered wheels 1 via the steering actuator 3, and controls the vehicle via the shift actuator 10. Forward / reverse switching control and vehicle stop control via the brake actuator 9 are performed. The ECU 5 implements automatic parking assist control for parking the vehicle in a desired parking space by automatic steering through these controls.

  FIG. 2 shows a functional block diagram of the ECU 5 that performs automatic parking assistance control. The function of each block can be realized by the CPU of the ECU 5.

  The width detector 31 detects the width of the parking space and the width of the road facing the parking space based on signals from the sonars 13R and 13L. Referring now to FIG. 3, a state where the vehicle V is traveling on the road R toward the parking space P is shown. Area 101L indicates the detection area of sonar 13L, and area 101R indicates the detection area of sonar 13R.

  The distance DL to the object existing on the left side of the vehicle V, in the example shown, is measured by the sonar 13L, and the distance DR from the sonar 13R to the object present on the right side of the vehicle V, the wall in the example shown in the figure. Is measured. The ECU 5 can detect the road width RoadW by receiving these measured distances DL and DR from the sonars 13L and 13R, and calculating DL + DR + Wv using the vehicle width of the vehicle V as Wv.

  Moreover, the width PslotL of the parking space P can be detected by detecting an empty parking space. An empty parking space can be detected in any suitable manner. For example, the distance measured by the sonar 13L becomes a predetermined value or less when the vehicle passes in front of another vehicle adjacent to the parking space P, and becomes a predetermined value or more when the vehicle passes in front of the parking space P. Therefore, the travel distance of the vehicle V while the measurement distance of the sonar 13L is equal to or greater than the predetermined value (this can be calculated from the detection values of the wheel speed sensors 7, 8 as is well known) Can be used as the width PslotL of the parking space P.

  Alternatively, an empty parking space may be detected based on an image captured by the camera 11F. Any appropriate technique can be used. For example, the width PslotL of the parking space P is calculated by recognizing the vehicles adjacent to both sides of the parking space P by image processing and calculating the distance between the two vehicles. be able to. Further, when the parking space is divided by a white line as shown in FIG. 3, the white line is detected, and if no other vehicle is detected in the area between the white lines, it is determined as an empty parking space, The distance between the white lines can be the width PslotL of the parking space P. Note that the image processing may be performed on the overhead image converted based on the captured image.

  A coordinate system as shown in FIG. 4A is set for the parking space P thus detected. In this embodiment, the center of the portion (entrance) in contact with the road R of the parking space P is set as the origin O, the y-axis is taken in a direction perpendicular to the entrance, and the x-axis is taken along the entrance. The inclination with respect to the x-axis is represented by θ. θ takes a negative value in the clockwise direction and takes a positive value in the counterclockwise direction. 4B, the position of the vehicle V is represented by the position of the midpoint of the rear wheel (on the axle) (alternatively, for example, the position of the center of gravity of the vehicle) May be used). In response to the detection of the parking space P, the position of the vehicle V is tracked according to the wheel speed pulses from the wheel speed sensors 7 and 8, and the coordinate system of FIG. 4A is (Px, Py). And the vehicle orientation is represented by the inclination θ of the axle with respect to the x-axis.

  Returning to FIG. 2, the parking possibility determination unit 33 refers to the parking route table 41 stored in advance in the memory of the ECU 5 based on the detected width PSlotL of the parking space P and the detected width RoadW of the road R. And the candidate of the parking route which can park in the parking space P is extracted from this table.

  Here, the parking route table 41 will be described. In this embodiment, the parking route includes a route for parking in the parking space with only one turnover and a route for parking in the parking space with a plurality of turnovers, and the latter is further classified into two types.

  FIG. 5 shows a route in which the vehicle head portion is turned with respect to the parking space P to stop and parked in the parking space P with only one turn, which is indicated by a solid line. The parking route includes a route 121 that moves forward while turning right and a route 123 that moves backward while turning left. Therefore, the parking route includes a steering start point (x0, y0) which is a position where the steering in the right direction is started, and a steering completion point (x1, y1) which is a position where the steering in the right direction is finished. ), As shown in the path 121, the center point (cx1, cy1) of the turning circle when moving forward while turning rightward, the radius Rr0 of the turning, the first turning point (x2) that is the position to turn back from forward to backward , Y2), the center point (cx2, cy2) of the turning circle when turning backward while turning left as shown in the path 123, and the radius Rr of the turning.

  The coordinate value and radius value of these points can be determined in advance based on the width of the parking space P and the width of the road R. Therefore, as shown in the table at the bottom of the figure, the parking route table 41 includes, for parking mode 0, for each combination of the width of the parking space and the width of the road (the width of the parking space set in the table is TblPslot). The road width is represented by TblLoadW), and the coordinate values and radius values of these points are determined in advance by simulation or the like and stored. As shown in the table, even when the width of the parking space and the width of the road are the same, the number of paths for parking is not limited to one, and a plurality of possible parking paths can be defined. These coordinate values and radius values follow the coordinate system of FIG. 4 (a), and this is the same hereinafter.

  FIG. 6 shows a route in which the vehicle head part is turned with respect to the parking space and stopped, and the parking space P is parked in three turns, which is indicated as a solid line. The parking path includes a path 131 that moves forward while turning right, a path 133 that moves backward while turning left, a path 135 that moves forward while turning right, and a path that moves backward while turning left. 137. Therefore, the parking route includes a steering start point (x0, y0) which is a position where the steering in the right direction is started, and a steering completion point (x1, y1) which is a position where the steering in the right direction is finished. ), As shown in the path 131, the center point (cx1, cy1) of the turning circle when moving forward while turning rightward, the radius Rr0 of the turning circle, and the first turning point that is the position to turn back from forward to backward ( x2, y2), the center point (cx2, cy2) of the turning circle when turning backward while turning left as shown in the path 133, the radius Rr of the turning circle, and the second position that switches from backward to forward The turning point (x3, y3), the center point (cx3, cy3) of the turning circle when moving forward while turning right as shown in the path 135, the radius Rr of the turning circle, and the position where the turning circle is turned from forward to backward. Third turning point (x4, y4), The center point of the turning circle when retracted while turning to the left as shown in the road 137 (cx4, cy4), is defined by the radius Rr of the orbiting circle.

  The coordinate values and radius values of these points can be predetermined based on the width of the parking space and the width of the road. Therefore, as shown in the table below, in the parking route table 41, for the parking mode 1, the coordinate values and radius values of these points are simulated for each combination of the width of the parking space and the width of the road. Etc. are determined in advance and stored.

  FIG. 7 shows a route in which the vehicle is stopped in a state substantially parallel to the entrance of the parking space and parked in the parking space P by turning back twice, which is referred to as a parking mode 2. This parking path includes a path 141 that moves backward while turning left, a path 143 that moves forward while turning right, and a path 145 that moves backward while turning left. Therefore, the parking path includes a steering start point (x0, y0) that is a position at which leftward steering is started, and a steering completion point (x1, y1) that is a position at which the leftward steering ends. ), As shown in the path 141, the center point (cx1, cy1) of the turning circle when moving backward while turning leftward, the radius Rr of the turning circle, and the first turning point (the position at which turning from backward to forward) ( x2, y2), the center point (cx2, cy2) of the turning circle when moving forward while turning right as shown in the path 143, the radius Rr of the turning circle, and the second position that switches back from forward to backward The turning point (x3, y3), the center point (cx3, cy3) of the turning circle when turning backward while turning left as shown in the path 145, and the radius Rr of the turning circle are defined.

  The coordinate values and radius values of these points can be predetermined based on the width of the parking space and the width of the road. Therefore, as shown in the table at the bottom of the figure, in the parking route table 41, for the parking mode 2, for each combination of the width of the parking space and the width of the road, the coordinate value and the radius value of these points are respectively simulated. Etc. are determined in advance and stored.

  Returning to FIG. 2, the parking availability determination unit 33 refers to the parking table 41 as described above, the parking space width PSlotL and the road width RoadW detected by the width detection unit 31, and each parking path of the table 41. Are compared with the width TblPslot of the parking space and the width TblLoadW of the road defined in the above, and based on the comparison result, a parking route suitable for the detected width PSlotL of the parking space and the road width RoadW is extracted as a candidate. . If a candidate is extracted, it is determined that parking is possible, and if a candidate is not extracted, it is determined that parking is impossible.

  If it is determined that parking is possible, the parking route selection determination unit 35 selects a parking route most suitable for the initial position (Px0, Py0) where the vehicle V is stopped for parking from among these candidates.

  Specifically, in one embodiment, a parking route having the y coordinate value y0 of the turning start point closest to the y coordinate value Py0 of the initial position of the vehicle V is selected. Thereby, guidance to the parking route of the vehicle can be realized more accurately and easily.

  In one embodiment, for at least parking modes 0 and 1, a parking route is selected in which the x-coordinate value Px0 of the initial position of the vehicle V is ahead of the x-coordinate value x1 of the turning completion point. Explaining this basis, the route between the turning start point (x0, y0) and the turning completion point (x1, y1) described above with reference to FIGS. 5 to 6 is the first turning point (x2). , Y2), it is set as a margin route for guiding the vehicle. For example, when the x-coordinate value Px0 of the vehicle V is smaller than the x-coordinate value x0 of the turning start point (Px0 <x0), the turning start point of the vehicle V is controlled by forward shifting control (described later). The vehicle V is gradually steered and guided to the first turning point by turning control along a turning circle having a radius Rr0 centered on (cx1, cy1) after that. Can do. Even when the x coordinate value Px0 of the vehicle V is between the x coordinate value x0 of the turning start point and the x coordinate value x1 of the turning completion point (x0 ≦ Px0 <x1), (cx1, cy1) is the center By turning control along the turning circle of radius Rr0, the vehicle V can be guided to the first turning point by turning faster than the above. In any case, the “deviation” with respect to the parking path of the vehicle V in the y direction when starting the turn control can be corrected in the turn control.

  Thus, the x-coordinate value x1 of the turning completion point is the state in which the vehicle V is separated from the parking route by a predetermined distance (this is determined in advance according to the road width of the parking route) in the y direction. Even when the turning control is started, the upper limit x-coordinate value at which the vehicle V can be guided to the first turning point is set. Therefore, in this embodiment, at least in the parking modes 0 and 1, the parking route is selected on the condition that the x coordinate value Px0 of the initial position of the vehicle V does not exceed the x coordinate value x1 of the turning completion point. . By doing so, the vehicle can be guided to the first turning point while maintaining the traveling direction of the vehicle.

  On the other hand, in the parking mode 2, the route between the turning start point (x0, y0) and the turning completion point (x1, y1) in FIG. 7 moves the vehicle toward the first turning point (x2, y2). The point set as a margin route for guidance is the same as in parking modes 0 and 1. The x-coordinate value x1 of the turning completion point starts turning control in a state where the vehicle V is separated from the parking route by a predetermined distance (this is determined in advance according to the road width of the parking route) in the y direction. Even so, it is set to indicate the lower limit x-coordinate value at which the vehicle V can be guided to the first turning point.

  However, parking paths in parking modes 0 and 1 start from the forward movement of the vehicle (see paths 121 and 131), whereas parking paths in parking mode 2 start from the backward movement of the vehicle (see path 141). . Therefore, in the parking mode 2, when the x-coordinate value Px0 of the initial position of the vehicle V is in front of the x-coordinate value x1 of the turning completion point (Px0 <x1), the vehicle moves forward as in the parking modes 0 and 1. By performing the width shifting control, the vehicle can be guided to the x coordinate value x0 of the turning start point. When Px0 is between the x-coordinate value x0 of the turning start point and the x-coordinate value x1 of the turning completion point (x1 ≦ Px0 <x0), as in the parking modes 0 and 1, the vehicle is first controlled by turning control. Can be guided to the turning point. When Px0 is equal to or greater than x0 (Px0 ≧ x0), the vehicle can be guided to the x coordinate value x0 of the turning start point by performing the reverse width-shifting control (described later). That is, in the case of the parking mode 2, the vehicle can be guided to the parking route not only when Px0 is smaller than x1 but also when it is large. The route selection based on the comparison process between Px0 and x1 may not be performed.

  The parking route selection determination unit 35 displays to the occupant which area on the road R the parking route thus selected uses. Specifically, when the parking route for the parking mode 0 or 1 is selected, the parking route selection determining unit 35 is a road through which the selected parking route passes through the image ahead of the vehicle imaged by the front camera 11F. The area is superimposed and displayed on the display device 15. The occupant can confirm whether there is an obstacle on the route through which the vehicle passes when parking, by visually recognizing the display.

  FIG. 8 shows an example of such a display, and an area 151 is superimposed and displayed on an image captured by the camera 11F of the vehicle V. The area 151 indicates a road area through which the parking route passes.

  In the parking mode 0, as shown in FIG. 5, on the road R ahead of the vehicle, an area from the initial position (Px0, Py0) of the vehicle to the first turning point (x2, y2) is used. Further, when the vehicle reaches the first turning point, the head of the vehicle is set to the x coordinate value x2 in the length in the axle direction of the vehicle (more precisely, between the pair of rear wheels used as the position of the vehicle). The distance from the point to the front end of the vehicle). Therefore, the boundary 151d in the distance direction of the region 151 is calculated to correspond to the value obtained by adding the length in the vehicle axle direction to the x coordinate value x2 of the first turning point, and the left and right boundary 151h of the region 151 is It is calculated so as to correspond to the road width TblLoadW defined for the parking route. Also in the parking mode 1, as in the parking mode 0, the area up to the first turning point (x2, y2) is superimposed and displayed as the area 151.

  Furthermore, the parking route selection determination unit 35 displays two selection buttons 155 and 157 that can be selected by the occupant together with a character display “Is there an obstacle in the area?”. The OK button 155 represented by a circle is provided so that the occupant can select when there is no obstacle in the area 151, and in response to the OK button 155 being selected, the parking route selection determining unit 35 determines the parking path selected and displayed as a parking path used for automatic steering. The NG button 157 represented by a cross is provided so that the occupant can select, for example, when there is an obstacle in the area 151, and the parking route selection decision is made according to the selection of the NG button 157. The unit 35 stops execution of automatic steering using the selected and displayed parking route.

  Even when the parking route for the parking mode 2 is selected, the parking route selection determination unit 35 performs the display as shown in FIG. 8. In this case, the parking route selection determination unit 35 selects the image behind the vehicle captured by the rear camera 11R. The road area through which the parking path is passed is displayed in a superimposed manner on the display device 15. Here, the boundary 151d in the distance direction of the region 151 is calculated so as to correspond to the x coordinate value x2 (see FIG. 7) of the first turning point (more precisely, the position of the vehicle (the middle of the pair of rear wheels)). The distance from the point) to the rear end of the vehicle may be added), and the left and right boundaries 151h of the region 151 are calculated to correspond to the road width TblLoadW. The point that the character display and the two selection buttons are displayed in a superimposed manner is the same as described above.

  In addition, it is preferable that selection and determination of a parking route are performed according to the priority of parking mode 0, 1 and 2. It is preferable to check at least the parking route in the parking mode 0 in preference to the other parking modes 1 and 2. This is because the parking route in the parking mode 0 is the simplest route, so that the vehicle can be efficiently guided with a low load.

  Returning to FIG. 2, the parking control unit 37 uses the parking route determined by the parking route selection determination unit 35 as the target parking route, and turns the steering wheel (steering) 1 of the vehicle to guide the vehicle V along the target route. Control is performed via the steering actuator 3.

  Thus, since the parking route suitable for the width of the parking space and the road width is stored in advance in the parking route table 41 for each parking mode, it is not necessary to calculate the target parking route in real time. As a result, it is possible to reduce a calculation load when performing automatic steering, and it is possible to suppress an increase in cost because a radar or the like necessary for real-time calculation is not required.

  In addition, a parking space that requires turning back when parked can be parked by automatic steering. That is, when there is a margin in the width of the road R facing the parking space P, the vehicle can be parked according to the parking route in the parking mode 0, and parking can be performed with only one turn. On the other hand, even when there is relatively little margin in the width of the road R, the vehicle can be parked according to the parking mode 1 or 2 in which the turnover is performed multiple times. Moreover, even when the vehicle V has gone too far with respect to the parking space P, it can park according to the parking mode 2. FIG.

  Next, with reference to FIGS. 9-21, the process performed by CPU of ECU5 which performs the automatic vehicle assistance control shown in FIG. 2 is demonstrated concretely.

  FIG. 9 shows the main flow of the automatic parking assistance process. In this embodiment, the process starts in response to the occupant selecting a predetermined switch for starting automatic parking provided on the vehicle.

  In step S1, the driver is notified via voice and / or display to move forward at a low speed (preferably 10 km / h or less) while bringing the vehicle toward the parking space. Here, the player may be prompted to take out the winker in the direction in which the user wants to park through voice and / or display.

  While the driver is traveling the vehicle as described above, in step S2, as described above, based on the distance signal measured by the sonars 13R and 13L, the vacant parking space P is detected, and the An attempt is made to detect the width PSlotL of the parking space P and the width RoadW of the road R. In step S3, it is determined whether or not these width data have been acquired. If not, the process returns to step S1. If these width data are acquired, it will progress to step S4.

  In step S4, a parking permission determination process (FIG. 10) is executed, the parking route table 41 is referenced based on the detected width PslotL of the parking space P and the width RoadW of the road R, and parking route candidates are extracted. Determine if parking is possible. In step S5, if the result of the determination is that parking is possible, the process proceeds to step S6, and if parking is not possible, the process returns to step S1. By returning to step S1, it is possible to determine whether or not parking is possible for the next empty parking space.

  In step S6, the driver is instructed to stop the vehicle via voice and / or display. In step S7, it is determined whether the vehicle has stopped. If not stopped, the process returns to step S6. If the vehicle stops, the stop position is stored in the memory as the initial position (Px0, Py0). In step S8, a parking route selection determination process (FIGS. 11 and 12) is executed, and a parking route is selected from the parking route candidates based on the stop position (Px0, Py0) of the vehicle, and input from the occupant. Based on this, it is determined whether to use the selected parking route as the target parking route.

  In step S9, a parking control process (FIGS. 13 to 14) is executed, the vehicle is automatically steered according to the target parking route, and the vehicle is parked in the parking space.

  FIG. 10 shows the parking permission / inhibition determination process executed in step S4 of FIG. In step S101, nPark represents the parking mode, and takes one of the values 0, 1, and 2 as described above. Step S101 indicates that the processes in steps S102 to S106 are repeated for each parking mode.

  In step S102, the width PslotL of the parking space P detected in step S2 of FIG. 9 is compared with the width TblPslot of the parking space defined for each parking route in the parking route table 41, and TblPslot ≦ PslotL <TblPslot + 0.1. A parking route that satisfies the condition is extracted as a candidate. Here, the unit is meters (m), and 0.1 meter indicates an example of a value set as a margin.

  In step S103, the road width LoadW detected in step S2 is compared with the road width TblLoadW of the parking path extracted as a candidate in step S102, and a parking path satisfying LoadW ≧ TblLoadW is extracted in step S102. Further extracted from the candidate parking route. TblLoadW indicates the minimum road width necessary for the parking route. Since the narrower the road, the more difficult the parking is, so a parking route is selected on the premise that the road width is equal to or smaller than the detected road width LoadW. Thereby, the path | route which can be parked reliably can be selected.

  Thus, for example, if the detected parking space width is 2.5 m and the detected road width is 4.6 m, the parking space width is 2.5 m or more and less than 2.6 m, and A parking route having a road width of 4.6 m or less is finally extracted as a candidate. Note that the order of steps S102 and S103 may be switched.

  In step S104, it is determined whether or not there are finally extracted candidates as a result of steps S102 and S103. If array data POK [] having each parking mode (nPark) as an entry is set in advance and there is a candidate for parking mode 0, a value 1 is set to POK [0] in step S105. If there is no candidate for the parking mode nPark = 0, zero is set to POK [0] in step S106. The same applies to other parking modes.

  In step S107, the values of all entries of the array data POK [] are summed. If the value 1 is set in any entry, that is, if there is a candidate for any parking mode, the total value should be greater than zero. In this case, since parking can be performed using the parking route extracted as a candidate, it is determined in step S108 that parking is possible. If the total value is zero, it indicates that no candidate has been extracted for any parking mode, so it is determined in step S109 that parking is impossible. One or a plurality of parking routes extracted as candidates are stored in the memory of the ECU 5 and used in subsequent processing.

  11 and 12 show the flow of the parking route selection determination process executed in step S8 of FIG.

  Step S121 is similar to step S101 in FIG. 10, and indicates that steps S122 to S126 are repeated for each parking mode.

  In step S122, it is determined whether 1 is set for the array data POK [nPark]. If 1 is not set, it indicates that no candidate parking route has been extracted for the parking mode indicated by nPark, and the process proceeds to step S131. If 1 is set, it indicates that a candidate parking route is extracted for the parking mode, and the process proceeds to step S123. Steps S123 and S124 are the steps that define the conditions for selecting the parking route described above.

  In step S123, the absolute value of the y-coordinate value Py0 of the position (Px0, Py0) when the vehicle stops in steps S6 and S7 in FIG. A parking route with a minimum value obtained by adding the y coordinate value y0 of the start point is selected. Here, y0 takes a negative value as shown in FIGS. The absolute value of Py0 represents the distance from the entrance of the parking space P of the host vehicle. Therefore, the parking route having the steering start point closest to the host vehicle in the y direction is selected. In this way, it is possible to select a parking route that most easily guides the vehicle.

  In step S124, the x coordinate value Px0 of the stop position of the vehicle is compared with the x coordinate value x1 of the turning completion point of the parking route selected in step S123, and it is determined whether the former is smaller than the latter. . It is checked whether at least one of Px0 <x1 is established and the parking mode (nPark) is 2 is established. As for the parking modes 0 and 1, as described above, it is difficult to guide the vehicle to the parking route even if a parking route having a turning completion point located behind the vehicle is selected. Therefore, for parking modes 0 and 1, if Px0 <x1 is satisfied, the determination in step S124 is Yes. Thus, since the parking route having the steering completion point on the traveling direction of the vehicle is selected, the vehicle can be guided to the parking route while maintaining the traveling direction of the vehicle.

  On the other hand, in the parking mode 2, as described above, the vehicle can be guided to the parking path even if the parking path having the turning completion point located behind the vehicle is selected. Therefore, if nPark = 2, even if Px0 <x1 does not hold (here, the comparison process between Px0 and x1 does not have to be performed), the determination in step S124 is Yes.

  If the determination in step S124 is Yes, the value 1 is set in the array data POK [nPark] in step S125. If the determination in step S124 is No, in step S126, array data POK [nPark] is set to zero. At this time, the parking route selected as satisfying steps S123 and S124 is stored in the memory of the ECU 5. Thus, for each parking mode, a parking route having a steering start point closest to the vehicle is selected, and at least for parking modes 0 and 1, a parking route having a steering completion point in the traveling direction of the vehicle is selected. Will be.

  In addition, the order of step S124 and S123 may be switched and the parking route which satisfy | fills the conditions of step S123 may be selected among the parking routes which satisfy | fill the conditions of step S124. Alternatively, if the condition of step S124 is not satisfied for the parking route selected in step S123, the parking route in which | Py0 | + y0 is the next smallest is selected, and the condition of step S124 is satisfied for the selected route. It may be determined whether or not. Thus, the parking route may be selected in ascending order of | Py0 | + y0 until a parking route satisfying the condition of step S124 is found.

  Proceeding to step S131 (FIG. 12), it is determined whether or not the value of entry POK [0] of parking mode 0 in the array data is 1. If it is 1, it indicates that a parking route in the parking mode 0 is selected, so the process proceeds to step S132, and PMODE is set to zero. In step S133, a display as shown in FIG. That is, as described above, the size of the road area 151 used by the selected parking route is calculated based on the x coordinate x2 of the first turning point of the selected parking route and the road width TblLoadW, The road area 151, characters for prompting confirmation of obstacles on the road area 151, and selection buttons 155 and 157 indicating OK and NG are superimposed on the captured image in front of the vehicle acquired by the camera 11F. The occupant confirms whether or not there is an obstacle on the road area 151 through this display, and if not, selects the OK button 155, otherwise selects the NG button 157.

  In step S134, it is determined whether or not the OK button 155 has been selected by the passenger. If the OK button 155 is selected, the parking route is determined as the target parking route in step S135.

  If the determination in step S131 is No, it indicates that the parking route in the parking mode 0 has not been selected, and the process proceeds to step S136. If the NG button 157 is selected in step S134, it indicates that, for example, an obstacle exists in the selected parking route and the parking route cannot be used, and the process proceeds to step S136.

  In step S136, it is determined whether the value of the entry POK [1] in the parking mode 1 of the array data is 1. If it is 1, it indicates that the parking route in the parking mode 1 is selected, so the process proceeds to step S137, and 1 is set in PMODE. Proceeding to step S138, similarly to step S133, the size of the road area 151 used by the selected parking route is determined based on the x coordinate x2 of the first turning point of the selected parking route and the road width TblLoadW. The road area 151, characters for prompting confirmation of obstacles on the road area 151, and selection buttons 155 and 157 indicating OK and NG are added to the captured image in front of the vehicle acquired by the camera 11F. Superimposed display. The occupant confirms whether or not there is an obstacle on the road area 151 through this display, and if not, selects the OK button 155, otherwise selects the NG button 157.

  In step S139, it is determined whether or not the OK button 155 has been selected by the passenger. If the OK button 155 is selected, the parking route is determined as the target parking route in step S135. If the NG button 157 is selected, in step S143, the occupant is notified through voice and / or display that parking is impossible, and the automatic parking assistance process is stopped.

  If the determination in step S136 is No, it indicates that there is no selected parking route for parking modes 0 and 1. In step S140, it is determined whether or not the value of the entry POK [2] in the parking mode 2 of the array data is 1. If it is 1, it indicates that the parking route in the parking mode 2 is selected, so the process proceeds to step S141, and 2 is set in PMODE. In step S138, the size of the road area 151 used by the selected parking route is calculated based on, for example, the x coordinate x2 of the first turning point of the selected parking route and the road width TblLoadW, and the camera 11R The road area 151, characters for prompting confirmation of obstacles on the road area 151, and selection buttons 155 and 157 indicating OK and NG are superimposed and displayed on the captured image of the rear of the vehicle acquired by the above. The occupant confirms whether or not there is an obstacle on the road area 151 through this display, and if not, selects the OK button 155, otherwise selects the NG button 157. The processing after step S139 is as described above.

  If the determination in step S140 is No, it indicates that the selected parking route does not exist in any of the parking modes 0, 1, and 2. Therefore, in step S143, the automatic parking assistance process is stopped.

  In the parking mode 0, the width of the road area to be used is relatively wide compared to the parking modes 1 and 2. Due to the presence of some kind of obstacle, the parking path in the parking mode 0 cannot be used, but the parking path in the parking mode 1 or 2 can be used. Therefore, in this embodiment, when the parking route in the parking mode 0 cannot be determined as the target parking route (when Step S134 is No), the determination of the parking route in the parking mode 1 or 2 is attempted. In this embodiment, since the parking modes 1 and 2 have substantially the same width of the road area to be used, if the determination in step S139 is No, the process proceeds to step S143 as it is. When determination of S139 is No, you may progress to step S140.

  13 and 14 show a flow of the parking control process executed in step S9 of FIG. In this process, the vehicle is automatically steered so that the vehicle is placed on the target parking route determined in the parking route selection determination process and guided along the route.

  In step S151, it is checked whether or not the value of PMODE is 2. If the value of PMODE is 2, it indicates that the parking mode of the target parking route is the parking mode 2, and the process proceeds to step S152. If the value of PMODE is 0 or 1, it indicates that the parking mode of the target parking route is the parking mode 0 or 1, and the process proceeds to step S153.

  The step S152 will be described. As described above, in the parking mode 2, the guidance for placing the vehicle on the target parking route differs according to the position of the x coordinate value Px0 of the initial position of the vehicle. That is, there are three patterns for the guidance, and the first pattern is when Px0 is in front of the x coordinate value x1 of the turning completion point (that is, Px0 <x1), and the vehicle is turned by moving the vehicle forward. Guide to the rudder start point. The second pattern is a case where Px0 is between the x-coordinate value x1 of the turning completion point and the x-coordinate value x0 of the turning start point (that is, x1 ≦ Px0 <x0), and the vehicle is moved backward. The vehicle is guided to the first turning point by turning control to turn left. The third pattern is a case where Px0 is greater than or equal to the x coordinate value of the turning start point (that is, Px0 ≧ x0), and is guided to the turning start point by reversing the vehicle. In the case of the first and third patterns, after the vehicle is guided to the turning start point, the vehicle is guided to the first turning point by turning control as in the second pattern.

  In the first pattern, guidance to the target parking path of the vehicle starts from the forward direction, and in the second and third patterns, guidance to the target parking path of the vehicle starts from the backward direction. The distinction between forward and reverse is performed in step S152. That is, if Px0 <x1, the process proceeds to step S153 in order to start guidance of the vehicle to the target parking route from forward. If Px0 ≧ x1, the process proceeds to step S165 in order to start guiding the vehicle to the target parking route from the reverse.

  In step S153, in order to guide the vehicle toward the steering start point defined for the target parking route, forward width-shifting control is performed to bring the vehicle closer to the line y = y0. This will be described later. Also in the case of the first pattern in the parking mode 2, the advance width adjustment control is performed.

  In step S154, it is checked whether or not the value of PMODE is 2. As described above, if the value of PMODE is 2, it indicates that the target parking route is the parking mode 2. If the value of PMODE is 0 or 1, the apparent parking route is the parking mode 0 or 1. It shows that.

  In the latter case (No in step S154), the process proceeds to step S155, where the x-coordinate value Px of the current position of the vehicle is compared with the x-coordinate value x0 of the turning start point of the target parking route. It is determined whether or not has reached the turning start point. If judgment of Step S155 is No, it will return to Step S153 and will continue advance width adjustment control. Thus, if the x-coordinate value x0 of the steering start point is reached while the vehicle is getting closer to y = y0, the process proceeds to step S156. As described above, when the x-coordinate value Px0 of the initial position of the vehicle is between x0 and x1, it indicates that the vehicle has already reached the turning start point, so the determination in step S155 is It becomes Yes and progresses to step S156. The “deviation” with respect to the target parking path of the vehicle in the y direction when starting the forward right turn control in step S156 can be corrected until the vehicle is guided to the first turning point.

  Steps S156 and S157 are executed for the target parking route in the parking mode 0 or 1. In step S156, forward right turn control is executed to move forward with a turn radius Rr0 (m) while turning rightward. With this control, the vehicle is guided along the route 121 (FIG. 5) in the parking mode 0, and the vehicle is guided along the route 131 (FIG. 6) in the parking mode 1.

  In step S157, the current position (Px, Py) of the vehicle is compared with the first turning point (x2, y2) of the target parking route to determine whether or not the vehicle has reached the first turning point. If not, the process returns to step S156 to continue forward right turn control. If it has reached, the process proceeds to step S158, and a vehicle stop request is issued to the brake actuator 9. The brake is driven by the brake actuator 9, and the vehicle stops. Alternatively, in step S158, the driver may be notified via voice and / or display to stop the vehicle, and this also applies to the following.

  If the vehicle has stopped, the process proceeds to step S160, and reverse left turn control is started with the turn radius Rr (m) turning backward while turning left. In step S161, it is determined whether or not the shift position detected by the shift position sensor 6 is R (reverse). If not, a request to set the shift position to R is issued to the shift actuator 10 in step S162. As a result, the shift position is changed to R by the shift actuator 10. If it is determined that the shift position is R, the process proceeds to step S171 (FIG. 14). Alternatively, in step S162, the driver may be notified via voice and / or display to change the shift position to R. This also applies to the following.

  On the other hand, when the determination in step S154 is Yes, that is, in the parking mode 2, the process proceeds to step S159. As described above, the x-coordinate value Px of the current position of the vehicle is between the x-coordinate value x0 of the turning start point and the x-coordinate value x1 of the turning completion point (referred to as the reverse start position). ), It is necessary to switch to turning control. Therefore, in step S159, it is determined whether or not the Px has entered between x0 and x1 (reverse starting position). If this judgment is No, it will return to Step S153 and will continue advance width adjustment control. If this determination is Yes, the vehicle is stopped (S158), the steering is started and the reverse left turn control is executed (S160 to S162), and the vehicle is guided to the first turning point. The “deviation” with respect to the target parking path of the vehicle in the y direction when starting the reverse left turn control in step S160 can be corrected until the vehicle is guided to the first turning point.

  Returning to step S152, if the determination in step S152 is No, the process proceeds to step S165 as described above. In step S165, it is determined whether or not the shift position detected by the shift position sensor 6 is R (reverse). If not, a request to set the shift position to R is issued to the shift actuator 10 in step S166. As a result, the shift position is changed to R by the shift actuator 10. If it is determined that the shift position is R, the process proceeds to step S167, and the backward width-shifting control to the line y = y0 is executed. This will be described later. In step S168, the x-coordinate value Px of the vehicle is compared with the x-coordinate value x0 of the turning start point, and it is determined whether or not the vehicle has reached the turning start point in the x direction. If judgment of Step S168 is No, it will return to Step S167 and will continue retreat width adjustment control of vehicles. If the determination in step S168 is yes, the process proceeds to step S160, and the above-described reverse left turn control is executed. As described for the second pattern, when the x coordinate value Px0 of the initial position of the vehicle is between x0 and x1, the steering start point has already been reached, so the determination in step S168 is performed. Becomes Yes, and the process immediately proceeds to the backward left turn control in step S160. Also in this case, the “deviation” with respect to the target parking path of the vehicle in the y direction when starting the reverse left turn control in step S160 is the reverse left turn control until the vehicle is guided to the first turning point. Can be modified.

  Proceeding to step S171 (FIG. 14), it is determined whether PMODE is greater than zero. If it is greater than zero, PMODE represents parking mode 1 or 2. In this case, since the turn-back is performed a plurality of times, steps S172 to S185 are executed.

  In step S172, the backward left turn control is executed to move backward while turning leftward at the turn radius Rr. With this control, in the parking mode 1, the vehicle is guided along the route 133 (FIG. 6), and in the parking mode 2, the vehicle is guided along the route 141 (FIG. 7).

  In step S173, when the target parking route is the parking mode 1, the current position (Px, Py) of the vehicle is compared with the second turning point (x3, y3) of the route. It is determined whether or not the turning point is reached. When the target parking route is in the parking mode 2, the current position (Px, Py) of the vehicle is compared with the first turning point (x2, y2) of the route, and the vehicle becomes the first turning point. Determine if it has been reached. In any case, if not reached, the process returns to step S172, and the reverse left turn control is continued. If it has reached, the process proceeds to step S174, and the vehicle is stopped by driving the brake actuator 9.

  In step S181, forward right turn control is started to move forward while turning right at the turn radius Rr (m). In step S182, it is determined whether or not the shift position detected by the shift position sensor 6 is D (forward). If not, in step S183, the shift actuator 10 is driven to set the shift position to D, and the process proceeds to step S181. Return. If it is determined in step S182 that the shift position is D, the process proceeds to step S184.

  In step S184, if the target parking is in the parking mode 1, the current position (Px, Py) of the vehicle is compared with the third turning point (x4, y4) of the route, and the vehicle Determine if the cut-off point has been reached. When the target parking is in the parking mode 2, the current position (Px, Py) of the vehicle is compared with the second turning point (x3, y3) of the route, and the vehicle reaches the second turning point. Determine if you did. In any case, if not reached, the process returns to step S181 to continue forward right turn control. Accordingly, in the parking mode 1, the vehicle is guided along the route 135 (FIG. 6), and in the parking mode 2, the vehicle is guided along the route 143. If it has reached, the process proceeds to step S185, and the vehicle is stopped by driving the brake actuator 9.

  If the vehicle stops, the process proceeds to step S191. In step S171, if PMODE is not greater than zero, that is, if the parking mode is zero, the process proceeds to step S191. That is, the process of steps S191 to S196 is executed regardless of the parking mode in which the target parking is performed.

  In step S191, reverse left turn control is started to turn backward while turning leftward at the turn radius Rr (m). In step S192, it is determined whether or not the shift position detected by the shift position sensor 6 is R (reverse). If not, in step S193, the shift actuator 10 is driven to set the shift position to R.

  If it is determined that the shift position is R, it is determined in step S194 whether the vehicle inclination θ is smaller than (−90 + predetermined value). The predetermined value is, for example, 5 degrees. As the vehicle retreats to the parking space P, the vehicle inclination (inclination of the axle with respect to the x-axis as described above) θ approaches −90 degrees. Therefore, when this determination is No, it is determined that the retreat to the parking space P is insufficient, and the process returns to step S191 to continue the reverse left turn control. Thus, in the parking mode 0, the vehicle is guided along the route 123 (FIG. 5), in the parking mode 1, the vehicle is guided along the route 137 (FIG. 6), and in the parking mode 2, the vehicle is guided along the route 145. Is guided along.

  If the determination in step S194 is Yes, in step S195, reverse width-shifting control is executed in order to park the vehicle along the y-axis (that is, the line x = 0). This will be described later. In step S196, the current position (Px, Py) of the vehicle is compared with a predetermined completion point to determine whether or not the vehicle has reached the completion point. The completion point is a point having a positive value on the y-axis located at a predetermined distance from the origin O. The completion point indicates a final parking position and is determined in advance. If the completion point has not been reached, the process returns to step S195 to continue the backward width adjustment control. When the completion point is reached, the process is exited.

  FIG. 15 shows the process of forward shifting control executed in step S153 of FIG. In step S201, based on the wheel speed pulses from the rear wheel speed sensors 7 and 8, the vehicle current position (Px, Py) and the vehicle inclination θ are calculated.

As described above, the stop position (Px0, Py0) is used as the initial position, and the inclination of the vehicle at the stop position is θ0. From the stopped position, the position (Px, Py) and the inclination θ of the vehicle after the lapse of time Δt can be calculated as follows. That is, the amount of change dθ (degrees) in the slope at time Δt is calculated by equation (1). Here, dLR and dLL indicate the distance of the right rear wheel and the distance of the left rear wheel, respectively, and the right wheel speed obtained from the wheel speed pulses of the right wheel speed sensor 8 and the left wheel speed sensor 7 and It is obtained by multiplying the left wheel speed by the time Δt. LB represents the tread size of the rear wheel (the length (m) between the right rear wheel and the left rear wheel).

Therefore, the inclination θ can be calculated by the equation (2).
θ = θ0 + dθ (2)

By using the inclination θ, the x-coordinate change amount dx and the y-coordinate change amount dy are calculated by the equations (3) and (4), respectively.
dx = 0.5 × (dLR + dLL) · cos θ (3)
dy = 0.5 × (dLR + dLL) · sin θ (4)

Therefore, the position (Px, Py) of the vehicle after the lapse of Δt is calculated by equations (5) and (6).
Px = Px0 + dx (5)
Py = Py0 + dy (6)

  Next, in step S202, the vehicle V is widened to the line of the y coordinate value y0 of the steering start point of the parking path determined as the target parking path based on the current position and the inclination θ of the vehicle calculated in step S201. A target steering angle TA for approaching is calculated.

Here, referring to FIG. 16, a state in which the vehicle V is brought closer to positions A1 to A3 with the target of a straight line y = y0 represented by a dotted line is shown. The position (Px, Py) of the vehicle is indicated by a black circle. The target steering angle TA is determined according to the following equation (7) so that the distance and angle with respect to the target locus with respect to the target locus (y = y0 straight line) of the vehicle are zero.
TA (degrees) = − A × (Py−y0) −B × θ (degrees) (7)

  Here, A and B are coefficients that take a predetermined positive value. The target steering angle TA takes a negative value when steering in the clockwise direction, and takes a positive value when steering in the counterclockwise direction.

  As an example, if A = 400 and B = 30, the distance (Py−y0) at position A1 in FIG. 16 is −1.0 m and the inclination θ is 2.0 degrees, the target steering angle TA is 340 degrees. Steer leftward. If the value of the distance (Py−y0) at the position A2 is −0.7 m and the inclination θ is 6.0 degrees, the target steering angle is 100 degrees, and the steering angle is also reduced according to the shortening of the distance. . If the value of the distance (Py−y0) at the position A3 is −0.3 m and the inclination θ is 10 degrees, the target steering angle is −180 degrees, steering to the right is performed, and the vehicle is moved to the left. It works to return the tilt. Thus, the target steering angle TA is determined so as to correct the steering angle using the term of the coefficient A relating to the distance and the term of the coefficient B relating to the angle.

  Returning to FIG. 15, since the maximum value Smax and the minimum value −Smax of the steering angle are determined (for example, Smax = 520 degrees), limit processing is performed in steps S203 to S206. Specifically, if the calculated target steering angle TA is larger than the maximum value Smax in step S203, the maximum value is set as the target steering angle TA in step S204, and the process proceeds to step S207. If the calculated target steering angle is smaller than the minimum value −Smax in step S205, the minimum value is set as the target steering angle TA in step S206, and the process proceeds to step S207. If both the determinations in steps S203 and S205 are No, the process proceeds to step S207 without performing a limit process on the calculated target steering angle TA.

  In step S207, the steering 1 is steered via the steering actuator 3 so that the current steering angle detected by the steering angle sensor 4 (FIG. 1) matches the target steering angle TA.

In the backward width-shifting control executed in step S167 of FIG. 13, the target line is the same as the above-described forward width-shifting control (y = y0), but the sign of angle correction with respect to the target locus of the vehicle is the same. Vice versa. Therefore, the target steering angle TA is calculated according to the equation (8). Coefficients A and B may be the same as in equation (7). The process of FIG. 15 can be similarly applied except that the target steering angle TA is calculated according to the equation (8) in step S202.
TA (degrees) = − A × (Py−y0) + B × θ (degrees) (8)

  FIG. 17 shows a flow of the backward width adjusting control process executed in step S195 of FIG. The difference from FIG. 15 is step S212, and the other steps are the same, and thus the description thereof is omitted.

In the backward width adjusting control, the y-axis (x = 0 straight line) is used, and the target line is different from the forward width adjusting control of FIG. Therefore, the target steering angle TA is calculated according to the following equation (9). Coefficients A and B may be the same as in equation (7).
TA (degrees) = − A × Px + B × (θ + 90) (degrees) (9)

  FIG. 18 shows a process of forward right turn control executed in step S156 of FIG. 13 and step S181 of FIG. Here, the case where it is executed in step S156 will be described as an example.

  In step S221, as described above with respect to step S201, the vehicle current position (Px, Py) and the vehicle inclination θ are calculated based on the wheel speed pulses from the wheel speed sensors 7 and 8 for the rear wheels.

  In step S222, based on the current position (Px, Py) and the inclination θ of the vehicle calculated in step S221, a right turn with a turning radius Rr0 around the point (cx1, cy1) of the parking path determined as the target parking path. A target steering angle TA for turning the vehicle V in the direction is calculated.

Here, referring to FIG. 19, a state in which the vehicle V is guided to the turning circle 301 having the radius Rr0 of the point (cx1, cx2) is shown. The position (Px, Py) of the vehicle V is separated from the turning circle 301 by a distance of dR in the radial direction. Further, the angle of the tangent 303 of the turning circle 301 perpendicular to the line connecting the vehicle position (Px, Py) and the center of the circle (cx1, cx2) with respect to the x axis is represented by θ ′. The difference between the vehicle inclination θ and θ ′ is represented by dθ. The target steering angle TA is determined according to the following equation (10) so that the distance dR and the angle difference dθ are zero. Here, D and E are coefficients that take a predetermined positive value.
TA = −D · dR−E · dθ−TA0 (10)

The target steering angle TA takes a negative value when steering in the clockwise direction, and takes a positive value when steering in the counterclockwise direction. TA0 is a basic turning angle necessary to maintain the turning travel at the radius Rr0. Therefore, the equation (10) is corrected by the terms of dR and dθ when deviating from the turning circle 301 having the radius Rr0. Here, dR, dθ, and TA0 are respectively expressed as follows.

  Here, LWB indicates the wheel base of the vehicle (distance between the front wheel axis and the rear wheel axis), and LB indicates the tread size as described above. C is a coefficient set to the ratio (TP / TW) of the steering angle TP of the steered wheels to the outer wheel turning angle TW of the vehicle V, and is preset (for example, 16.2). The outer wheel turning angle TW is the turning angle of the front wheel that follows the outer locus when the vehicle is turned. Since the relationship between the inner wheel turning angle (the front wheel turning angle that follows the inner locus during turning) and the steering wheel steering angle TP is not linear, the outer wheel turning angle TW is used instead of the inner wheel turning angle. .

  Returning to FIG. 18, the processing in steps S223 to S227 is the same as the processing in steps S203 to S207 in FIG.

  When executing the process of FIG. 18 in step S181, the coordinates of the turning radius and the center point of the turning circle may be changed. That is, when executing Step S181 for the parking route in the parking mode 1, the turning radius is Rr, and the coordinates of the center point of the turning circle are (cx3, cy3). Therefore, in each of the above equations, Rr0 may be replaced with Rr, and cx1 and cy1 may be replaced with cx3 and cy3. When step S181 is executed for the parking route in the parking mode 2, the turning radius is Rr, and the coordinates of the center point of the turning circle are (cx2, cy2). Therefore, in each of the above equations, Rr0 may be replaced with Rr, and cx1 and cy1 may be replaced with cx2 and cy2.

  FIG. 20 shows a flow of the reverse left turn control process executed in steps S160, S172, and S191 of FIGS. What is different from FIG. 18 is step S232, and the other steps are the same, and the description thereof will be omitted. Here, the backward left turn control executed in step S160 will be described as an example for the parking routes in the parking modes 0 and 1.

FIG. 21 is similar to FIG. 19 and shows a state in which the vehicle V is guided to the turning circle 401 having the radius Rr and the center point (cx2, cy2) while moving backward. The position (Px, Py) of the vehicle V is separated from the turning circle 401 by a distance of dR in the radial direction. Further, the angle of the tangent line 403 of the turning circle 401 perpendicular to the line connecting the vehicle position (Px, Py) and the center of the circle (cx2, cy2) to the x-axis is represented by θ ′. The difference between the vehicle inclination θ and θ ′ is dθ. The target steering angle TA can be determined according to the equation (15) so that the distance dR and the angle difference dθ are zero. Coefficients D and E may be the same as in equation (10).
TA = D · dR + E · dθ + TA0 (15)

  Equations (11)-(14) above can be applied similarly, where cx1 and cy1 are replaced with cx2 and cy2, and Rr0 is replaced with Rr.

  With respect to the parking route in the parking mode 2, in the backward left turn control executed in step S160, the center of the turn circle may be set to (cx1, cy1). In the backward left turn control executed in step S172, (cx2, cy2) is used as the center point for the parking mode 1 route, and (cx1, cy1) is used as the center point for the parking mode 2 route. It is done. In the reverse left turn control executed in step S191, (cx2, cy2) is used as the center point for the parking mode 0 route, and (cx4, cy4) is used as the center point for the parking mode 1 route. For the parking mode 2 route, (cx3, cy3) is used as the center point.

  In the above-described embodiment, the form of parking while retreating to the parking space on the left side of the vehicle has been described. However, the present invention can be similarly applied to the form of parking while retreating to the parking space on the right side of the vehicle. is there. Further, the present invention can be similarly applied to parallel parking. In these cases, the parking route table 41 defines the parking route for these parking modes according to the width of the parking space and the width of the road.

  As described above, specific embodiments of the present invention have been described. However, the present invention is not limited to these embodiments.

1 Steering 3 Steering actuator 5 ECU
11R, 11L Camera 13R, 13L Sonar

Claims (5)

A parking assistance system for parking a vehicle in a parking space by automatic steering,
Means for detecting the width of the parking space;
Means for detecting the width of the road facing the parking space;
Position specifying means for specifying the position of the vehicle with respect to the parking space;
A parking route table in which a parking route to be parked in the parking space by one turn-back and a parking route to be parked in the parking space by a plurality of turn-backs are defined in advance according to the width of the parking space and the width of the road facing the parking space;
Means for reading the parking route candidates from the parking route table based on the detected width of the parking space and the width of the road;
Selecting means for selecting one of the read out parking route candidates based on the position of the vehicle specified by the position specifying means when the vehicle stops for parking;
Drive means for driving steering of the vehicle to guide the vehicle according to the selected parking path;
A parking assistance system comprising: For each of the read parking route candidates, the position of the vehicle specified by the position specifying means when the vehicle stops for parking is defined by the read parking route candidate. Means for determining whether or not the vehicle is ahead of the traveling direction of the vehicle from the position where the steering is completed toward the turning position;
The selection means selects a parking route that is determined to be in front of the traveling direction of the vehicle, from among the read parking route candidates, at least for the parking route that starts from a route in which the vehicle advances in the forward direction To
The parking assistance system according to claim 1. Means for driving steering of the vehicle to guide the vehicle to a position where steering is started toward the first turn-back position defined by the selected parking route;
The parking assistance system according to claim 1 or 2. Display means for displaying an area on the road through which the vehicle is parked based on the selected parking route;
An input means for causing the occupant to input a determination as to whether or not to start automatic steering of the vehicle with respect to the display of the area on the road,
The driving means starts guidance of the vehicle according to the selected parking route when a decision to start the automatic steering is input by the occupant via the input means;
The parking assistance system according to any one of claims 1 to 3. The means for detecting the width of the parking space and the means for detecting the width of the road are arranged such that when the vehicle is traveling toward the parking space on the road facing the parking space, the width of the parking space and the road Detect the width of the road,
The parking assistance system according to any one of claims 1 to 4.

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