JP2019077376A - Parking support device - Google Patents

Abstract

To provide a parking support device capable of creating a track of as small turning radius as possible even when capacity of an EPS motor is small.SOLUTION: A parking support ECU 2 comprises: a target parking position setting unit 23 which sets a target parking position to park a vehicle 1; a track creating unit 24 which creates an ideal track from a vehicle 1 position to the target parking position; a guiding control unit 26 which performs an automatic steering to move the vehicle 1 along the ideal track by driving the EPS motor 9; and a storage unit 28 which stores correspondence between a seated condition of each seat and an allowable steering angle that is the largest steering angle capable of being operated by the EPS motor 9 while the vehicle 1 is stopped. The allowable steering angle when a maximum number of persons are on board is smaller than the maximum steering angle. The track creating unit 24 acquires a detection result of a seat sensor 44 detecting the seated condition, reads out the allowable steering angle corresponding to the detected seated condition from the storage unit 28, and creates the ideal track based on the allowable steering angle.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a parking assistance device that assists a parking operation of a driver.

  Conventionally, a parking assist device has been developed that assists the driver's parking operation. The parking assistance device creates an ideal track from the current position of the car to the target parking position for parking. Then, the driver assists the parking operation so that the car travels along the track. The parking assistance device inputs a steering angle to an EPS (Electric Power Steering) -ECU (Electronic Control Unit) that is an electronic control unit that controls a steering mechanism. The EPS-ECU drives the EPS motor in accordance with the steering angle to control the steering mechanism. Thus, automatic steering is performed so that the vehicle travels on the track. An example of such a parking assistance device is disclosed, for example, in Patent Document 1.

  When the parking assist device is set to perform automatic steering, the maximum steering that can be steered by the steering mechanism even under the strictest conditions (in the case where the maximum number of passengers are on the stationary side (steering in a stopped state)) An EPS motor with a sufficiently large capacity is used to enable steering to the corner (hereinafter referred to as the "maximum steering angle"). Generally, a motor with a capacity of 65 A is used as an EPS motor. Since the output torque of the motor is sufficiently large, even when the EPS-ECU receives the maximum steering angle as the steering angle under the severest conditions, steering to the maximum steering angle can be performed. However, large capacity motors are heavy and expensive. Since weight reduction of parts and cost reduction are required, making an EPS motor small in capacity is considered.

JP, 2016-60234, A

  However, an EPS motor with a small capacity may not be able to steer up to the maximum steering angle due to a lack of output torque. In this case, the parking assistance device can not continue the parking assistance and is interrupted. In order to avoid this, it is sufficient to create a trajectory to the target parking position within the range of steering angles at which the EPS motor can steer even under the severe conditions. However, in this case, the generated trajectory is a large orbit and a trajectory with a large number of turns.

  The present invention has been conceived under the above-described circumstances, and it is an object of the present invention to provide a parking assistance device capable of creating a small orbit as much as possible even when the capacity of the EPS motor is small.

  In order to solve the above-mentioned subject, in the present invention, the following technical measures are taken.

  The parking assistance device provided by the present invention comprises target parking position setting means for setting a target parking position for parking a car, and track creation for creating an ideal track from the position of the car to the target parking position. Means, guidance control means for performing automatic steering for moving the car along the ideal track by driving a motor, a seating condition regarding the presence or absence of seating of each seat, and the stop of the car And a storage unit for storing the correspondence relationship with the allowable steering angle, which is the maximum steering angle at which the motor can steer, and the allowable steering angle when the maximum number of people can ride can be steered by the steering mechanism of the vehicle The trajectory creating means acquires the detection result of the seating condition detection unit for detecting the seating condition, and the allowable steering angle corresponding to the detected seating condition is smaller than the maximum steering angle, which is the maximum steering angle. Read from 憶部, based on the allowable steering angle, and wherein the creating the ideal trajectory.

  In a preferred embodiment of the present invention, the track creating means drives the motor to steer at a predetermined steering angular velocity up to the read out allowable steering angle, and the actual steering is performed until the allowable steering angle is reached. When the angular velocity becomes smaller than the threshold angular velocity, the ideal trajectory is created based on the steering angle at this time.

  According to the present invention, the track creating means creates an ideal track based on the allowable steering angle corresponding to the actual seating situation. Therefore, it is possible to create an ideal trajectory as small as possible according to the actual number of passengers.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is a block diagram showing composition of a car in which a parking assistance device concerning a 1st embodiment was applied. (A) is an example of the figure which shows the relationship between a steering angle and the output torque of an EPS motor at the time of a stop for every boarding number of people, (b) is a figure which shows an example of an allowable steering angle table. It is a figure which shows an example of the flowchart for demonstrating the start process of the parking assistance process which concerns on 1st Embodiment. It is a figure for demonstrating the ideal track | orbit when the target parking position which needs switching is selected. It is a figure which shows an example of the flowchart for demonstrating the repetition process of the parking assistance process which concerns on 1st Embodiment. It is a figure which shows an example of the image displayed on the display screen of a display.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of a car 1 to which a parking assistance device according to the first embodiment is applied. As shown in FIG. 1, the car 1 includes a parking assist ECU 2, a right side camera 31, a left side camera 32, a front camera 33, a rear camera 34, a steering angle sensor 41, a steering angular velocity sensor 42, a vehicle speed sensor 43, and a seat sensor 44. , An operation device 5, a speaker 6, a display 7, an EPS-ECU 8, and an EPS motor 9. In addition, although the vehicle 1 is also equipped with the other structure, description is abbreviate | omitted in FIG.

  The right side camera 31, the left side camera 32, the front camera 33, and the rear camera 34 are respectively imaging devices for capturing an image around the car 1, and include, for example, imaging devices such as CCD and CMOS, The area is photographed at a predetermined frame rate. The right side camera 31 is attached to the right door mirror (for example, the bottom surface thereof) and captures an image of the right side of the car 1 including the right side surface of the car 1 and the road surface. The left side camera 32 is attached to a left door mirror (for example, the bottom surface thereof) and captures an image of the left side of the car 1 including the left side surface of the car 1 and the road surface. The front camera 33 is attached near the center in the vehicle width direction of the front of the car 1 and captures an image of the front of the car 1 including the front of the car 1 and the road surface. The rear camera 34 is attached, for example, near the center in the vehicle width direction of the back door, and captures an image of the rear of the car 1 including the rear surface of the car 1 and the road surface. In addition, the attachment position of these cameras is not limited. Image data captured by each of the cameras 31 to 34 is output to the parking assist ECU 2.

  The steering angle sensor 41 is a sensor that detects the steering angle of a steering wheel (not shown). The steering angle sensor 41 detects the rotation angle from the neutral position of the steering wheel as the steering angle θ. The steering angle sensor 41 sets the neutral position to 0 [deg], takes a positive value when the steering wheel is rotated in one direction, and takes a negative value when the steering wheel is rotated in the other direction, the steering angle θ To detect In the present embodiment, since the maximum steering angle is 550 [deg], −550 [deg] ≦ θ ≦ 550 [deg] is obtained. The steering angle sensor 41 detects the steering angle θ by detecting the rotation angle of the steering shaft to which the steering wheel is connected, for example, with a Hall element. The method of detecting the steering angle θ is not limited. The steering angle sensor 41 outputs a signal indicating the detected steering angle θ to the parking assist ECU 2.

  The steering angular velocity sensor 42 is a sensor that detects the angular velocity of the steering wheel. The steering angular velocity sensor 42 detects an amount of change per hour (angular velocity) of the steering angle of the steering wheel as a steering angular velocity. In addition, the detection method of a steering angular velocity is not limited. Instead of providing the steering angular velocity sensor 42 separately, it may be calculated from the steering angle detected by the steering angle sensor 41 and the time measured by the timer. The steering angular velocity sensor 42 outputs a signal indicating the detected steering angular velocity to the parking assist ECU 2.

  The vehicle speed sensor 43 is a sensor that detects the wheel speed of each wheel of the car 1. The vehicle speed sensor 43 detects the rotational speed of the axle of each wheel, and calculates the wheel speed of each wheel based on these. The vehicle speed sensor 43 outputs a signal indicating each detected wheel speed to the parking assist ECU 2.

  The seat sensor 44 is a sensor that detects the seating condition of the driver and the passenger. Specifically, the seat sensor 44 includes a pressure sensor installed inside the seat of each seat, and detects the presence or absence of the seating of the seat based on the pressure detected by the pressure sensor. In this embodiment, the case where the car 1 is a mini car will be described. Therefore, the pressure sensors are respectively installed on the driver's seat (seat D), the passenger seat (seat P), the rear seat right side (rear R seat), and the rear seat left side (rear L seat). The number of pressure sensors provided in the sheet sensor 44 is not limited to this. The seat sensor 44 is provided with a number of pressure sensors corresponding to the number of people in the car 1. For example, if the car 1 is a 2-seater, two pressure sensors are installed, and if the passenger capacity is eight vans, eight pressure sensors are installed. The seat sensor 44 outputs a signal indicating the detected seating condition to the parking assist ECU 2. The seat sensor 44 corresponds to the “seating state detection unit” in the present invention. The configuration of the sheet sensor 44 is not limited to this. For example, a sensor that detects the attachment / detachment status of the seat belt of each seat may be provided to detect the seating status of each seat. Further, instead of the seat sensor 44, a camera for photographing the inside of a car and an image processing apparatus for recognizing a person from an image photographed by the camera may be provided to detect the seating condition of each seat. In this case, the camera and the image processing apparatus correspond to the “seating state detection unit” in the present invention. Also, the number of passengers may be detected instead of detecting the seating condition of each seat. In this case, the detected number of passengers corresponds to the "seating situation" of the present invention.

  The car 1 also includes other sensors, and detection values detected by these sensors may also be used for parking assistance. In the following, when collectively expressing the steering angle sensor 41, the steering angular velocity sensor 42, the vehicle speed sensor 43, the seat sensor 44, and other sensors, it will be referred to as "various sensors 4".

  The speaker 6 outputs a voice, and outputs a voice based on the voice signal input from the parking assistance ECU 2.

  The display 7 is configured of, for example, an LCD (Liquid Crystal Display), and is installed at a center console portion of the car 1. The display 7 is not limited to the LCD, and may be an organic EL display, a plasma display, or the like. Further, the installation position is not limited to the center console portion, and may be within a range where it can be seen by the driver. The display 7 displays the overhead view image based on the image signal input from the parking assistance ECU 2 at the time of parking assistance. The overhead image is an image displayed as if looking down from a virtual viewpoint above the car. The display 7 may also be used as a display of a navigation system or the like. In this case, when an operation signal for instructing the start of parking assistance is input from the operating device 5, the navigation screen may be switched to the parking assistance screen (the bird's-eye view image).

  The operating device 5 is operated by a driver (or a passenger) and outputs an operation signal corresponding to the operation to the parking assist ECU 2. In the present embodiment, the controller device 5 is a touch panel disposed on the screen of the display 7. When a button or the like displayed on the screen of the display 7 is operated with a fingertip, the touch panel reads a touch position and outputs a corresponding operation signal. The operation device 5 is not limited to this, and may be an input device such as an operation button or a joystick. The driver (or the passenger) can instruct the parking assistance ECU 2 to start parking assistance or designate a target parking position by the operation of the operation device 5.

  The EPS-ECU 8 is an electronic control unit that controls the steering mechanism. Under normal conditions, the EPS-ECU 8 controls the steering mechanism according to the steering wheel operation by the driver. That is, the EPS-ECU 8 detects the driver's steering wheel operation and drives the EPS motor 9 to assist the rotation in the detected operation direction. Further, at the time of parking assistance, the EPS-ECU 8 receives a steering angle from the parking assistance ECU 2 and drives the EPS motor 9 according to the steering angle to control the steering mechanism.

  In the present embodiment, the EPS motor 9 is a motor having a capacity of, for example, 50A. When a general 65A motor is used for the EPS motor, the output torque of the motor is large enough, so even under the most severe conditions (in the case of performing stationary operation with the maximum number of people on board), the EPS motor has maximum steering It is possible to steer to an angle (the maximum steering angle steerable by the steering mechanism). However, in the present embodiment, since the EPS motor 9 is a 50A motor, the steering angle that can be steered under the severest conditions is smaller than the maximum steering angle. Therefore, there is a limitation of the steering angle in the creation of the ideal trajectory described later. The capacity of the EPS motor 9 is not limited. In order to further reduce the size and weight of the EPS motor 9, for example, the capacity may be 45A. Also, in order to ease the restriction at the time of creation of the ideal trajectory, the capacity may be 55 A, for example.

  The EPS motor can output a torque according to the capacity, and can output a larger torque as the capacity is larger. The steering angle at which the EPS motor can steer is determined by the vehicle speed and the axle weight of the axle to be steered (hereinafter referred to as "steering axle weight"). The larger the vehicle speed, the larger the steerable steering angle. Also, the smaller the steering shaft weight, the larger the steerable steering angle. Further, the steering shaft weight changes depending on the number of passengers of the car 1 and becomes smaller as the number of passengers is smaller. Therefore, the smaller the number of passengers, the larger the steerable steering angle. Hereinafter, the maximum steering angle that can be steered when the vehicle is stopped (the vehicle speed is 0 km / h) will be referred to as “permissible steering angle”.

  FIG. 2A is an example of a diagram showing the relationship between the steering angle and the output torque of the EPS motor when the car 1 is stopped for each number of passengers. FIG. 2A is created by a simulation that calculates the output torque of the EPS motor while changing the steering angle. As shown in FIG. 2A, when the number of passengers is the same, the output torque increases as the steering angle increases. In the case of the same steering angle, the output torque is larger as the number of passengers is larger (as the steering shaft weight is larger). Further, in the case of the same output torque, the steering angle is smaller as the number of passengers is larger (as the steering shaft weight is larger). From FIG. 2A, from the maximum output torque N of the EPS motor 9, an allowable steering angle for each passenger can be determined. For example, when the number of passengers is four, the allowable steering angle is 150 [deg], and when the number of passengers is one, the allowable steering angle is 300 [deg]. In addition, the numerical value of the steering angle shown in FIG. 2 (a) is an illustration, Comprising: It is not limited to this. An allowable steering angle table indicating an allowable steering angle for each number of passengers is created in advance using the result of the simulation and set in the parking assist ECU 2.

  FIG. 2B is a diagram showing an example of the allowable steering angle table. The allowable steering angle table is set with the number of passengers corresponding to the seating condition detected by the seat sensor 44. For example, when the pressure sensor at the driver's seat (D seat) is ON and the other pressure sensors are OFF, the number of passengers is one, and when all the pressure sensors are ON, the number of passengers is four. In the present embodiment, when the pressure sensor at the driver's seat (seat D) is off, that is, the case where the driver is not seated at the driver's seat is not considered. However, it may be considered that the pressure sensor at the driver's seat (seat D) is off. Further, an allowable steering angle corresponding to the number of passengers is set in the allowable steering angle table. For example, the allowable steering angle when the number of passengers is four is 150 [deg]. That is, in this case, the EPS motor 9 can perform steering at a steering angle of -150 [deg] or more and 150 [deg] or less when the vehicle is stopped. On the other hand, when the vehicle is at a stop, the EPS motor 9 can not perform steering at steering angles less than -150 [deg] and greater than 150 [deg]. In addition, the numerical value of the allowable steering angle shown in FIG. 2 (b) is an example and is not limited thereto.

  In FIG. 2 (b), the allowable steering angle is set according to the number of passengers regardless of the seating position. For example, the number of passengers is the same when sitting in the driver's seat (D seat) and the passenger seat (P seat) and in the driver's seat (D seat) and the rear right seat (rear R seat). The steering angle is the same. Since the steering shaft weight changes in the case of sitting in the front passenger seat and in the case of sitting in the rear seat, the allowable steering angle may be set according to the sitting condition. Also, instead of the allowable steering angle table in which the correspondence relationship between the seating condition and the allowable steering angle is set, a first table in which the correspondence relationship between the seating condition and the number of passengers is set, the number of passengers and the allowable steering angle And the second table in which the correspondence relationship is set.

  The parking assistance ECU 2 is an electronic control unit for performing parking assistance, and is realized by a microcomputer including a CPU and a memory. The parking assist ECU 2 receives image data from each of the cameras 31 to 34 and creates an overhead image. And based on each signal inputted from various sensors 4 and the operation signal inputted from operation device 5, control for parking assistance is performed. For example, the parking assistance ECU 2 creates an ideal trajectory for parking, outputs a steering angle to the EPS-ECU 8 to assist steering wheel operation, creates an image for parking assistance, and displays it on the display 7 Let The parking assistance ECU 2 corresponds to the "parking assistance device" of the present invention.

  As shown in FIG. 1, the parking assistance ECU 2 has, as functional blocks, an overhead image creation unit 21, a parking frame detection unit 22, a target parking position setting unit 23, a track creation unit 24, a vehicle position estimation unit 25, and a guidance control unit 26, an image control unit 27, and a storage unit 28.

  The overhead image creation unit 21 creates an overhead image. The bird's-eye view image creation unit 21 creates a bird's-eye view image displayed as if looking down from a virtual viewpoint above the vehicle 1 from the image data input from each of the cameras 31 to 34 by predetermined image processing.

  The parking frame detection unit 22 detects a parking frame from the overhead image created by the overhead image creation unit 21. The parking frame detection unit 22 detects, for example, a white line, and detects a rectangular area formed by the white line as a parking frame. In addition, the method to detect a parking frame is not limited. The parking frame may be detected by image recognition processing such as pattern matching. The lines forming the parking frame are not limited to white lines, and may be yellow lines or lines of other colors, or may be broken lines. In addition, the parking frame is not limited to being formed in a rectangular shape, and may be formed in a parallelogram shape, or may be formed by only two parallel lines. Also in these cases, it is desirable to be able to detect as a parking frame.

  The target parking position setting unit 23 sets a target parking position. The target parking position setting unit 23 selects a parking frame for parking the car 1 from the parking frames detected by the parking frame detecting unit 22 and sets the position of the selected parking frame as a target parking position. A parking frame for parking the car 1 is automatically selected from the parking frames detected by the parking frame detection unit 22 according to a predetermined algorithm. Alternatively, all (or to some extent) the parking frame detected by the parking frame detection unit 22 may be displayed on the display 7, and the driver may be selected by the operation of the operating device 5. Alternatively, the parking frame detection unit 22 may not detect and display the parking frame, and the driver may set the parking frame on the overhead image by the operation of the operation device 5. In addition, the target parking position may be set by another method without using the overhead image. For example, a parking space may be detected by an ultrasonic sensor (sonar), and a parking space for parking the car 1 may be selected from the detected parking spaces and set as the target parking position. The setting method of the target parking position is not limited.

  The track creating unit 24 creates an ideal track for parking at the target parking position set by the target parking position setting unit 23 from the current position of the car 1. Hereinafter, the ideal trajectory created by the trajectory creation unit 24 will be referred to as an “ideal trajectory”. The trajectory creating unit 24 creates an ideal trajectory based on the allowable steering angle set in the allowable steering angle table (see FIG. 2B) stored in the storage unit 28. The trajectory generation unit 24 includes, as functional blocks, an allowable steering angle reference unit 241, a confirmation processing unit 242, and a trajectory generation unit 243.

  The allowable steering angle reference unit 241 reads the allowable steering angle with reference to the allowable steering angle table. Specifically, the allowable steering angle reference unit 241 acquires information indicating the seating state based on the signal input from the seat sensor 44. Then, based on the acquired information, the allowable steering angle set in the allowable steering angle table is read out. For example, when only the driver is on the car 1, the information indicating the seating condition indicates that only the driver's seat (D seat) is ON and the others are OFF. In this case, the allowable steering angle is read out as 300 [deg] (see FIG. 2 (b)).

  The confirmation processing unit 242 confirms whether or not the allowable steering angle read by the allowable steering angle reference unit 241 is appropriate. For example, although the actual number of passengers is two, it may be determined that the number of passengers is one due to a detection error of the seat sensor 44 or the like. In this case, when the ideal track is created based on the allowable steering angle when the number of passengers is one, there is a possibility that the EPS motor 9 can not steer to the set steering angle at the time of parking assistance. In order to prevent this, the confirmation processing unit 242 determines whether the read allowable steering angle is appropriate.

  Specifically, the confirmation processing unit 242 instructs the EPS-ECU 8 to actually steer the vehicle to the read allowable steering angle while the vehicle 1 is stopped. At this time, the confirmation processing unit 242 issues an instruction to set the steering angular velocity to about half the maximum angular velocity (for example, 360 [deg / s]). This is to prevent that, when the EPS motor 9 steers at a large steering angular velocity, the steering force can be steered beyond the original allowable steering angle and the steering can not be returned. The steering angular velocity to be instructed is not limited, and may be about 25% to 75% of the maximum angular velocity. Then, the confirmation processing unit 242 acquires an actual steering angular velocity based on a signal input from the steering angular velocity sensor 42. If the read-out allowable steering angle is appropriate, the EPS motor 9 can steer to the allowable steering angle without the actual steering angular velocity being reduced. On the other hand, if the read-out allowable steering angle is not appropriate, the actual steering angular velocity is reduced before the EPS motor 9 steers to the allowable steering angle. The confirmation processing unit 242 compares the actual steering angular velocity with the threshold angular velocity (for example, the angular velocity about half of the instructed steering angular velocity) for determining the blunting, and the read allowable steering angle is appropriate. Determine if it is or not.

  If the EPS motor 9 can steer to the allowable steering angle while the actual steering angular velocity is larger than the threshold angular velocity, the confirmation processing unit 242 determines that the read allowable steering angle is appropriate, and the allowable steering is performed. The angle is output to the trajectory generation unit 243. On the other hand, when the actual steering angular velocity becomes equal to or less than the threshold angular velocity before the EPS motor 9 steers to the allowable steering angle, it is determined that the read allowable steering angle is not appropriate. In this case, the confirmation processing unit 242 stops the steering of the EPS motor 9 when the actual steering angular velocity becomes equal to or less than the threshold angular velocity, and the allowable steering angle table is detected based on the steering angle detected by the steering angle sensor 41 at this time. Refer to to read the allowable steering angle. For example, it is assumed that it is determined that the number of passengers is one, and the allowable steering angle is read as 300 [deg] based on the allowable steering angle table of FIG. 2 (b). When the actual steering angular velocity becomes equal to or less than the threshold angular velocity at 210 [deg] although the user is instructed to actually steer up to 300 [deg], the actual number of passengers is three. It can be guessed that it was. Therefore, the confirmation processing unit 242 reads the allowable steering angle when the number of passengers is 3, and outputs the allowable steering angle to the track generation unit 243.

  The trajectory generation unit 243 creates an ideal trajectory in consideration of the allowable steering angle input from the confirmation processing unit 242. That is, the track creating unit 24 creates the ideal track such that the steering angle is equal to or less than the allowable steering angle. For example, when only the driver is on board (when the number of passengers is one), an ideal track is created such that the steering angle does not exceed 300 [deg]. The specific method of creating the ideal trajectory is not limited.

  The vehicle position estimation unit 25 estimates the current position of the car 1. The vehicle position estimation unit 25 estimates the current position of the car 1 from detection signals sequentially input from the various sensors 4 based on the position of the car 1 when parking assistance is started. Hereinafter, the estimated current position of the car 1 will be referred to as “estimated position”.

  The guidance control unit 26 guides the vehicle 1 so that the vehicle 1 can move on the ideal trajectory from the estimated position estimated by the vehicle position estimation unit 25 and the ideal trajectory generated by the trajectory creation unit 24. Specifically, the guidance control unit 26 calculates a steering angle at which the vehicle 1 can move on the ideal trajectory at the estimated position, and outputs the steering angle to the EPS-ECU 8.

  The image control unit 27 creates an image for parking assistance and causes the display 7 to display the image. In the present embodiment, an image (see FIG. 6) in which the display of a frame indicating a target parking position, the display of a trajectory indicating an ideal trajectory, and the display of a stop line for indicating a turning position is superimposed on the overhead image Let

  The storage unit 28 stores various programs and data for performing the parking assistance process, and also stores an allowable steering angle table (see FIG. 2B). The allowable steering angle table is stored in advance in the storage unit 28 in which the allowable steering angle for each passenger is set by simulation or experiment. The allowable steering angle table is referred to when creating the ideal trajectory in the parking assistance processing.

  Next, the parking support processing performed by the parking support ECU 2 will be described below with reference to the flowcharts shown in FIGS. 3 and 5.

  FIG. 3A is an example of a flowchart for explaining the process of starting the parking assistance process. The processing is performed at the start of the parking support processing, and is performed, for example, when an operation signal instructing the start of the parking support is input from the operating device 5. Note that this operation may be performed when there is an operation indicating an intention to perform parking, such as when the R range (reverse range) is selected by the shift operation.

  First, the position of the car 1 at the start of parking assistance (hereinafter referred to as "start position") is set (S1). In the following processing, each position is represented by coordinates with the start position as a reference (origin). Next, image data is input from each of the cameras 31 to 34 (S2), and the overhead image creation unit 21 creates a overhead image (S3). Next, a target parking position is set (S4). Specifically, the parking frame detection unit 22 detects a parking frame from the bird's-eye view image, and the target parking position setting unit 23 sets the position of the parking frame selected from among the detected parking frames as a target parking position. Information on the target parking position and direction (position and direction based on the starting position) is stored. Then, a trajectory creating process is performed by the trajectory creating unit 24 (S5), and the start process is ended.

  FIG. 3B is an example of a flowchart for explaining the trajectory creation process. The trajectory creating process is a subroutine shown in step S5 of the flowchart shown in FIG. 3 (a).

  First, the allowable steering angle reference unit 241 acquires information indicating the seating condition from the signal input from the seat sensor 44 (S11). Then, based on the acquired information, the allowable steering angle reference unit 241 reads the allowable steering angle set in the allowable steering angle table with reference to the allowable steering angle table (S12).

  Next, the confirmation processing unit 242 performs confirmation processing based on the read allowable steering angle (S13). Specifically, the confirmation processing unit 242 instructs the EPS-ECU 8 to actually steer to the allowable steering angle. Then, the confirmation processing unit 242 compares the actual steering angular velocity detected by the steering angular velocity sensor 42 with the threshold angular velocity. Then, the confirmation processing unit 242 determines whether the read allowable steering angle is appropriate (S14). When the EPS motor 9 can steer to the allowable steering angle while the actual steering angular velocity is larger than the threshold angular velocity, the confirmation processing unit 242 determines that the read allowable steering angle is appropriate (S14: YES And the trajectory generation unit 243. On the other hand, when the actual steering angular velocity becomes equal to or less than the threshold angular velocity before the EPS motor 9 steers to the allowable steering angle, it is determined that the read allowable steering angle is not appropriate (S14: NO). Based on the steering angle when the steering angular velocity becomes equal to or less than the threshold angular velocity, the allowable steering angle is read with reference to the allowable steering angle table (S15), and the allowable steering angle is output to the track generation unit 243.

  Next, the trajectory generation unit 243 creates an ideal trajectory in consideration of the allowable steering angle input from the confirmation processing unit 242 (S16). The ideal trajectory is stored as a set of position information based on the start position.

  FIG. 4 is a diagram for describing an ideal trajectory when a target parking position requiring a turnaround is selected. In FIG. 4, it is assumed that the parking assistance processing is started when the car 1 is located at the point P1. The point P1 is, for example, the center position of the car 1 (the same applies to the points P2 and P3).

  FIG. 4A shows the ideal trajectory when the number of passengers is one. The start processing of the parking assistance processing is executed at the point P1, and the point P1 is set as the start position. Then, it is assumed that the parking frame shown at point P2 is set as the target parking position from the detected parking frame. In the case of parking from the start position P1 to the target parking position P2, it is necessary to switch back and forth, and the trajectory L1 and the trajectory L2 are created as the ideal trajectory. The trajectory L1 is an ideal trajectory from the start position P1 to the turning position P3, and the trajectory L2 is an ideal trajectory from the turning position P3 to the target parking position P2. In the present embodiment, when it is necessary to switch back in parking, a stop line K1 for indicating the switch back position is set. The ideal trajectory consisting of the trajectory L1 and the trajectory L2 is created in consideration of the allowable steering angle (see FIG. 2B) when the number of passengers is one. In FIG. 4A, the ideal trajectory is created such that the steering angle does not become larger than 300 [deg].

  FIG. 4B shows the ideal trajectory when the number of passengers is four. As in the case of FIG. 4A, it is assumed that the point P1 is set as the start position and the point P2 is set as the target parking position. The ideal trajectory in FIG. 4B is created in consideration of the allowable steering angle (see FIG. 2B) when the number of passengers is four. In FIG. 4 (b), the ideal trajectory is created so that the steering angle does not become larger than 150 [deg]. Therefore, the ideal orbit is a large orbit, and it is an orbit that does not need to be turned back once, but needs to be turned back twice.

  FIG. 5A is an example of a flowchart for explaining the repetitive process of the parking assistance process. The processing is repeated until parking assistance is interrupted (for example, when an operation signal instructing termination of parking assistance is input from the operation device 5) after the start processing (see FIG. 3A) is ended. To be executed.

  First, detection signals are input from the various sensors 4 (S21), and the current position (estimated position) of the vehicle 1 is estimated by the vehicle position estimation unit 25 (S22). The estimated position is calculated as a position based on the start position P1. Next, a guidance process is performed by the guidance control unit 26 (S23). The guidance processing is processing for calculating a steering angle that allows the vehicle 1 to move on the ideal trajectory based on the estimated position and the ideal trajectory, and outputting the steering angle to the EPS-ECU 8. The EPS-ECU 8 performs steering by driving the EPS motor 9 according to the steering angle input from the guidance control unit 26. Then, the screen control process (S24) is performed by the image control unit 27.

  FIG. 5B is an example of a flowchart for explaining the screen display process. The screen display process is a subroutine shown in step S24 of the flowchart shown in FIG. 5 (a).

  First, it is determined whether image data is input from each of the cameras 31 to 34 (S31). When the input is not made (S31: NO), the screen display process is ended. When it is input (S31: YES), the overhead image creation unit 21 creates a overhead image (S32). The created bird's-eye view image data is stored by the image control unit 27 in an output buffer. Next, the display of the trajectory is superimposed on the overhead image (S33). Specifically, the image control unit 27 creates a trajectory after the estimated position based on the stored information of the ideal trajectory and the information of the estimated position, and uses the created image data of the trajectory as information of the buffer for output. Make it overlap. Next, the frame display is superimposed on the overhead image (S34). Specifically, the image control unit 27 creates a frame based on the stored information of the target parking position and direction and the information of the estimated position, and superimposes the created image data of the frame on the information of the output buffer Let Next, the display of the stop line for turning back is superimposed on the overhead image (S35). Specifically, the image control unit 27 creates a stop line based on the stored information on the position and direction of the stop line and the information on the estimated position, and generates the image data of the created stop line as a buffer for output. Superimpose on information. Then, the image data of the buffer for output is output to the display 7 by the image control unit 27, so that the overhead image on which the display of the track, the frame, and the stop line is superimposed is displayed on the display screen of the display 7. Then (S36), the screen display process is ended. Since the image displayed on the display 7 is rewritten each time the image data is input from each of the cameras 31 to 34, the display 7 is displayed as a moving image.

  FIG. 6 shows an example of an image displayed on the display screen of the display 7. FIG. 6A is an image when the parking assistance processing is started, and is an image displayed on the display screen of the display 7 in the state of FIG. 4A. FIG. 6 (b) is an image after the car 1 has traveled along the track L1 for a while. These images are overhead images displayed with the car 1 facing the top of the screen at the center of the screen. Then, in these images, the trajectories L1 and L2, the frame F1, and the stop line K1 are superimposed and displayed. By looking at these images, the driver can recognize the positional relationship between the car 1 and the frame F1 indicating the target parking position and the stop line K1 indicating the turnaround position, and the trajectory that the car 1 is to follow Can be recognized. The driver operates the accelerator and the brake to slowly advance the car 1 until the tip of the car 1 reaches the stop line K1. As the steering angle is input from the parking assist ECU 2 to the EPS-ECU 8 at any time according to the progress of the vehicle 1 and the steering mechanism is controlled, the driver does not have to operate the steering wheel. The track L1 and the track L2 are created in consideration of the allowable steering angle according to the number of passengers of the car 1. Therefore, the steering angle input from the parking assistance ECU 2 to the EPS-ECU 8 does not become a steering angle at which the EPS motor 9 can not be steered. When the car 1 reaches the turning position, the track L1 and the stop line K1 are not displayed. The driver selects the R range (reverse range) by the shift operation and then operates the accelerator and the brake to slowly reverse the car 1 until the car 1 falls within the frame F1.

  Note that each process shown in the flowcharts of FIGS. 2 and 4 is an example, and the parking assistance process is not limited to that described above.

  Next, the operation and effects of the parking assist ECU 2 according to the present embodiment will be described.

  According to the present embodiment, the track creation unit 24 reads out the allowable steering angle corresponding to the number of passengers from the allowable steering angle table according to the seating condition detected by the seat sensor 44. In the allowable steering angle table, an allowable steering angle for each number of passengers is set in advance. Then, the track creating unit 24 creates the ideal track in consideration of the read allowable steering angle. The ideal track is a smaller turning track because the smaller the actual number of passengers, the larger the allowable steering angle. Therefore, the parking assistance ECU 2 can create an ideal trajectory as small as possible according to the actual number of passengers. As a result, the parking assistance ECU 2 can propose an ideal trajectory with as little switching as possible. For example, the ideal trajectories L1 and L2 shown in FIG. 4 (a) when the number of passengers is one is smaller than the ideal trajectory shown in FIG. 4 (b) when the number of passengers is four. There is. In the case of FIG. 4 (a), since it is possible to create a small-turn ideal trajectory, a trajectory that requires only one turn is created.

  Further, according to the present embodiment, the trajectory creating unit 24 confirms whether or not the read allowable steering angle is appropriate before creating the ideal trajectory. Therefore, the parking assistance ECU 2 can prevent the ideal trajectory from being created based on the improper allowable steering angle.

  In the present embodiment, the track generation unit 24 includes the confirmation processing unit 242, and the confirmation processing unit 242 confirms whether the allowable steering angle is appropriate or not, but the present invention is limited thereto. Absent. The trajectory generation unit 243 may generate the ideal trajectory based on the allowable steering angle read out by the allowable steering angle reference unit 241 without providing the confirmation processing unit 242. In this case, the time until creating the ideal trajectory can be shortened.

  Further, in the present embodiment, the case where the trajectory generation unit 243 creates the ideal trajectory after the confirmation processing unit 242 confirms the appropriateness of the allowable steering angle has been described, but the present invention is not limited thereto. For example, after the permissible steering angle reference unit 241 reads the permissible steering angle, the trajectory generation unit 243 creates an ideal trajectory based on the permissible steering angle, and after the actual parking assistance starts by repeated processing, the confirmation processing unit A confirmation process by 242 may be performed. In this case, when the confirmation processing unit 242 determines that the allowable steering angle is not appropriate, the trajectory generation unit 243 may recreate the ideal trajectory based on the allowable steering angle read by the confirmation processing unit 242.

  Further, when the confirmation processing unit 242 determines that the allowable steering angle is not appropriate, the method of reading out the allowable steering angle from the allowable steering angle table is not limited to the above. For example, the allowable steering angle may be read out when the number of passengers is increased by one in the allowable steering angle table. In this case, the confirmation processing unit 242 may determine again whether the read allowable steering angle is appropriate.

  Moreover, although the case where only the seat sensor 44 detects the seating presence or absence of a seat was demonstrated by the pressure sensor in this embodiment, it is not restricted to this. For example, the weight of the person seated by the seat sensor 44 may be detected by the pressure sensor. In this case, the actual steering shaft weight can be calculated. Therefore, if the allowable steering angle corresponding to the steering shaft weight is set in the allowable steering angle table, the track creating unit 24 reads the allowable steering angle corresponding to the actual steering shaft weight to create the ideal track. Can. Therefore, the parking assistance ECU 2 can create an ideal trajectory that is as small as possible according to the actual steering shaft weight. In this case, the calculated steering axle weight corresponds to the "seating situation" of the present invention.

  The parking assistance apparatus according to the present invention is not limited to the embodiment described above. The specific configuration of each part of the parking assistance device according to the present invention can be varied in design in many ways.

1: Car 2: Parking support ECU
21: overhead image creation unit 22: parking frame detection unit 23: target parking position setting unit 24: trajectory creation unit 241: allowable steering angle reference unit 242: confirmation processing unit 243: trajectory generation unit 25: vehicle position estimation unit 26: Guidance control unit 27: image control unit 28: storage unit 31: right side camera 32: left side camera 33: front camera 34: rear camera 4: sensor 41: steering angle sensor 42: steering angular velocity sensor 43: vehicle speed sensor 44: seat Sensor 5: Operation device 6: Speaker 7: Display 8: EPS-ECU
9: EPS motor L1, L2: Trajectory K1: Stop line P1: Start position P2: Target parking position P3: Turn-back position F1: Frame

Claims (2)

Target parking position setting means for setting a target parking position for parking a car;
Orbit creation means for creating an ideal orbit from the position of the car to the target parking position;
Guidance control means for performing automatic steering for moving the vehicle along the ideal track by driving a motor;
A storage unit for storing a correspondence relationship between a seating condition regarding presence / absence of seating of each seat and an allowable steering angle which is a maximum steering angle at which the motor can steer when the vehicle is stopped;
Equipped with
The allowable steering angle at the time of maximum number of passengers is smaller than the maximum steering angle which is the maximum steering angle steerable by the steering mechanism of the vehicle,
The track creation means acquires a detection result of a seating condition detection unit that detects the seating condition, reads an allowable steering angle corresponding to the detected seating condition from the storage unit, and based on the allowable steering angle, Create the ideal trajectory,
A parking assistance device characterized by. The trajectory creation means
Driving the motor to steer at a predetermined steering angular velocity up to the read-out allowable steering angle;
If the actual steering angular velocity becomes smaller than the threshold angular velocity by the time the allowable steering angle is reached, the ideal trajectory is created based on the steering angle at this time.
The parking assistance device according to claim 1.

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