JP7027651B2 - Parking support device - Google Patents

Description

The present invention relates to a parking support device that assists a driver in parking operations.

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

When the parking support device is set to perform automatic steering, the maximum steering that can be steered by the steering mechanism even under the harshest conditions (when the maximum number of passengers is on board and the vehicle is stationary (steering while the vehicle is stopped)). An EPS motor with a sufficiently large capacity is used so that steering can be performed up to an angle (hereinafter referred to as "maximum steering angle"). Generally, a motor having a capacity of 65 A is used as the EPS motor. Since the output torque of the motor is sufficiently large, it is possible to steer to the maximum steering angle even when the EPS-ECU inputs the maximum steering angle as the steering angle under the strictest conditions. However, a motor having a large capacity is heavy and expensive. Since the weight reduction of parts and cost reduction are required, it is considered to make the EPS motor a small capacity.

Japanese Unexamined Patent Publication No. 2016-60234

However, the EPS motor having a small capacity may not be able to steer up to the maximum steering angle due to insufficient output torque. In this case, the parking support device cannot continue the parking support and is interrupted. In order to avoid this, it is sufficient to create a trajectory to the target parking position within the steering angle range in which the EPS motor can steer even under the harshest conditions. However, in this case, the created orbit becomes a large round orbit and becomes an orbit with a large number of turns.

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

In order to solve the above problems, the following technical means are taken in the present invention.

The parking support device provided by the present invention includes a target parking position setting means for setting a target parking position for parking a vehicle and a track creation for creating an ideal track from the position of the vehicle to the target parking position. Means, guidance control means for driving the motor to automatically steer the vehicle along the ideal track, seating status regarding the presence or absence of seating of each seat, and when the vehicle is stopped. The motor is provided with a storage unit that stores a correspondence relationship with an allowable steering angle, which is the maximum steering angle that can be steered, and the allowable steering angle when a maximum number of passengers are on board can be steered by the steering mechanism of the vehicle. It is smaller than the maximum steering angle, which is the maximum steering angle, and the trajectory creating means acquires the detection result of the seating condition detecting unit that detects the seating condition, and obtains the allowable steering angle corresponding to the detected seating condition. It is characterized in that the ideal trajectory is created by reading from the storage unit and based on the allowable steering angle.

In a preferred embodiment of the present invention, the trajectory creating means drives the motor so as to steer to the read allowable steering angle at a predetermined steering angular velocity, and actually steers 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 trajectory creating means creates an ideal trajectory based on the allowable steering angle corresponding to the actual sitting situation. Therefore, it is possible to create an ideal trajectory with as small a turn as possible according to the actual number of passengers.

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

It is a block diagram which shows the structure of the car to which the parking support device which concerns on 1st Embodiment is applied. (A) is an example of a diagram showing the relationship between the steering angle and the output torque of the EPS motor when the vehicle is stopped for each number of passengers, and (b) is a diagram showing 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 support process which concerns on 1st Embodiment. It is a figure for demonstrating the ideal trajectory when the target parking position which needs turning back is selected. It is a figure which shows an example of the flowchart for explaining the iterative process of the parking support 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 a configuration of a vehicle 1 to which the parking support device according to the first embodiment is applied. As shown in FIG. 1, the vehicle 1 includes a parking support 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. , The operating device 5, the speaker 6, the display 7, the EPS-ECU 8, and the EPS motor 9. Although the vehicle 1 has other configurations, the description is omitted in FIG.

The right side camera 31, the left side camera 32, the front camera 33, and the rear camera 34 are photographing devices for photographing an image around the vehicle 1, for example, provided with an image pickup element such as a CCD or CMOS, and predetermined photographing. The area is photographed at a predetermined frame rate. The right side camera 31 is attached to a right door mirror (for example, the bottom surface thereof), and captures an image of the right side of the vehicle 1 including the right side surface and the road surface of the vehicle 1. 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 vehicle 1 including the left side surface and the road surface of the vehicle 1. The front camera 33 is attached to the front portion of the vehicle 1 near the center in the vehicle width direction, and captures an image of the front of the vehicle 1 including the front surface of the vehicle 1 and the road surface. The rear camera 34 is attached to, for example, near the center of the back door in the vehicle width direction, and captures an image of the rear of the vehicle 1, including the rear surface and the road surface of the vehicle 1. The mounting position of these cameras is not limited. The image data taken by each of the cameras 31 to 34 is output to the parking support 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 of the steering wheel from the neutral position as the steering angle θ. The steering angle sensor 41 has a neutral position of 0 [deg], a positive value when the steering wheel is rotated in one direction, and a negative value when the steering wheel is rotated in the other direction. Is detected. In the present embodiment, since the maximum steering angle is 550 [deg], −550 [deg] ≦ θ ≦ 550 [deg]. 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 for 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 support 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 the amount of change (angular velocity) of the steering angle of the handle per hour as the steering angular velocity. The method for detecting the steering angular velocity is not limited. Instead of separately providing the steering angular velocity sensor 42, 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 support ECU 2.

The vehicle speed sensor 43 is a sensor that detects the wheel speed of each wheel of the vehicle 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 support ECU 2.

The seat sensor 44 is a sensor that detects the seating status of the driver and the passenger. Specifically, the seat sensor 44 includes a pressure sensor installed inside each seat, and detects whether or not the seat is seated based on the pressure detected by the pressure sensor. In this embodiment, a case where the vehicle 1 is a light vehicle will be described. Therefore, the pressure sensors are installed on the driver's seat (D seat), the passenger seat (P seat), the right side of the rear seat (rear R seat), and the left side of the rear seat (rear L seat), respectively. The number of pressure sensors included in the seat sensor 44 is not limited to this. The seat sensor 44 includes a number of pressure sensors corresponding to the capacity of the vehicle 1. For example, if the vehicle 1 is a two-seater, two pressure sensors are installed, and if the vehicle has a passenger capacity of eight, eight pressure sensors are installed. The seat sensor 44 outputs the detected signal indicating the seating status to the parking support ECU 2. The seat sensor 44 corresponds to the "seating state detection unit" of the present invention. The configuration of the seat sensor 44 is not limited to this. For example, a sensor for detecting 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 the vehicle and an image processing device for recognizing a person from the image captured by the camera may be provided to detect the seating status of each seat. In this case, the camera and the image processing device correspond to the "seating status detection unit" of the present invention. Further, instead of detecting the seating status of each seat, the number of passengers may be detected. In this case, the detected number of passengers corresponds to the "seating situation" of the present invention.

The vehicle 1 is also provided with other sensors, and the detection values detected by these sensors may also be used for parking support. In the following, when the steering angle sensor 41, the steering angular velocity sensor 42, the vehicle speed sensor 43, the seat sensor 44, and other sensors are collectively expressed, they are described as “various sensors 4”.

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

The display 7 is composed of, for example, an LCD (Liquid Crystal Display) and is installed in the center console portion of the vehicle 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 that can be seen by the driver. The display 7 displays a bird's-eye view image based on the image signal input from the parking support ECU 2 at the time of parking support. The bird's-eye view 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 for a navigation system or the like. In this case, when an operation signal instructing the start of parking support is input from the operation device 5, the navigation screen may be switched to the parking support screen (overhead image).

The operation device 5 is operated by the driver (or a passenger) and outputs an operation signal corresponding to the operation to the parking support ECU 2. In the present embodiment, the operation device 5 is a touch panel arranged 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 the 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 passenger) can instruct the parking support ECU 2 to start parking support or specify a target parking position by operating the operation device 5.

The EPS-ECU 8 is an electronic control unit that controls the steering mechanism. The EPS-ECU 8 normally controls the steering mechanism in response to a 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 so as to assist the rotation in the detected operation direction. Further, at the time of parking support, the EPS-ECU 8 receives a steering angle from the parking support 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 sufficiently large, so that the EPS motor can be steered at the maximum even under the strictest conditions (when the maximum number of passengers is on board and the stationary steering is performed). It is possible to steer up to an angle (the maximum steering angle that can be steered by the steering mechanism). However, in the present embodiment, since the EPS motor 9 is a motor of 50 A, the steering angle that can be steered under the strictest conditions is smaller than the maximum steering angle. Therefore, there is a limitation on the steering angle in creating the ideal trajectory, which will be described later. The capacity of the EPS motor 9 is not limited. In order to make the EPS motor 9 smaller and lighter, the capacity may be, for example, 45A. Further, in order to further relax the limitation at the time of creating the ideal trajectory, the capacity may be set to, for example, 55A.

The EPS motor can output torque according to the capacity, and the larger the capacity, the larger the torque can be output. The steering angle that the EPS motor can steer is determined by the vehicle speed and the axle load of the axle to be steered (hereinafter referred to as "steering axle load"). The higher the vehicle speed, the larger the steering angle that can be steered. Further, the smaller the steering axle load, the larger the steering angle that can be steered. Further, the steering axle load changes depending on the number of passengers in the vehicle 1, and decreases as the number of passengers decreases. Therefore, the smaller the number of passengers, the larger the steering angle that can be steered. In the following, the maximum steering angle that can be steered when the vehicle is stopped (vehicle speed is 0 km / h) is referred to as an “allowable 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 vehicle 1 is stopped for each number of passengers. FIG. 2A is created by a simulation of calculating 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. Further, in the case of the same steering angle, the output torque increases as the number of passengers increases (the heavier the steering axle load). Further, for the same output torque, the steering angle becomes smaller as the number of passengers increases (the heavier the steering axle load). From FIG. 2A, the allowable steering angle for each number of passengers can be determined from the maximum output torque N of the EPS motor 9. 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]. The numerical value of the steering angle shown in FIG. 2A is an example, and is not limited thereto. Using the result of the simulation, an allowable steering angle table showing an allowable steering angle for each number of passengers is created in advance and set in the parking support ECU 2.

FIG. 2B is a diagram showing an example of an allowable steering angle table. In the allowable steering angle table, the number of passengers corresponding to the seating condition detected by the seat sensor 44 is set. For example, when the pressure sensor of 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 this embodiment, the case where the pressure sensor of the driver's seat (D seat) is OFF, that is, the case where the driver is not seated in the driver's seat is not considered. However, the case where the pressure sensor in the driver's seat (D seat) is OFF may be considered. Further, the 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 steer at a steering angle of −150 [deg] or more and 150 [deg] or less when the vehicle is stopped. On the other hand, the EPS motor 9 cannot steer at a steering angle of less than −150 [deg] and larger than 150 [deg] when the vehicle is stopped. The numerical value of the allowable steering angle shown in FIG. 2B is an example, and is not limited thereto.

In FIG. 2B, 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 seated in the driver's seat (D seat) and passenger seat (P seat) and when seated in the driver's seat (D seat) and the right side of the rear seat (rear R seat), so it is permissible. The steering angles are the same. Since the steering axle load changes depending on whether the passenger is seated in the passenger seat or the rear seat, the allowable steering angle may be set according to the seating situation. Further, instead of the permissible steering angle table in which the correspondence between the seating situation and the permissible steering angle is set, the first table in which the correspondence between the seating status and the number of passengers is set, and the number of passengers and the permissible steering angle are used. It may be provided with a second table in which the correspondence of the above is set.

The parking support ECU 2 is an electronic control unit for providing parking support, and is realized by a microcomputer provided with a CPU and a memory. The parking support ECU 2 inputs image data from each of the cameras 31 to 34 and creates a bird's-eye view image. Then, control for parking support is performed based on each signal input from the various sensors 4 and the operation signal input from the operation device 5. For example, the parking support ECU 2 creates an ideal trajectory for parking, supports steering wheel operation by outputting the steering angle to the EPS-ECU 8, creates an image for parking support, and displays it on the display 7. Let me. The parking support ECU 2 corresponds to the "parking support device" of the present invention.

As shown in FIG. 1, the parking support ECU 2 has a bird's-eye view 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 as functional blocks. 26, an image control unit 27, and a storage unit 28 are provided.

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

The parking frame detection unit 22 detects the parking frame from the bird's-eye view image created by the bird's-eye view image creation unit 21. The parking frame detection unit 22 detects, for example, a white line, and detects a rectangular region formed by the white line as a parking frame. The method of detecting the parking frame is not limited. The parking frame may be detected by image recognition processing such as pattern matching. The line forming the parking frame is not limited to the white line, but may be a yellow line or a line of another color, or may be a broken line. Further, the parking frame is not limited to the case where it is formed in a rectangular shape, but may be formed in a parallelogram shape or may be formed only by two parallel lines. Even in these cases, it is desirable that the parking frame can be detected.

The target parking position setting unit 23 sets the 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 detection unit 22, and sets the position of the selected parking frame as the target parking position. The 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. It should be noted that all the parking frames detected by the parking frame detection unit 22 may be displayed on the display 7 (or selected to some extent), and the driver may be allowed to select the parking frames by operating the operation device 5. Further, the parking frame may be set on the bird's-eye view image by the driver by operating the operation device 5 without detecting and displaying the parking frame by the parking frame detecting unit 22. Further, the target parking position may be set by another method without using the bird's-eye view image. For example, a parking space may be detected by an ultrasonic sensor (sonar), a parking space for parking the car 1 may be selected from the detected parking space, and the target parking position may be set. The method of setting the target parking position is not limited.

The track creating unit 24 creates an ideal track for parking from the current position of the vehicle 1 to the target parking position set by the target parking position setting unit 23. In the following, 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 creating unit 24 includes a permissible steering angle reference unit 241, a confirmation processing unit 242, and an orbit generation unit 243 as functional blocks.

The permissible steering angle reference unit 241 reads out the permissible steering angle with reference to the permissible 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 in the car 1, the information indicating the seating status indicates that only the driver's seat (D seat) is ON and the others are OFF. In this case, the allowable steering angle is assumed to be 300 [deg] (see FIG. 2B) and is read out.

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, even though 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, if the ideal track is created based on the allowable steering angle when the number of passengers is one, the EPS motor 9 may not be able to steer to the set steering angle during parking assistance. In order to prevent this, the confirmation processing unit 242 determines whether or not the read allowable steering angle is appropriate.

Specifically, the confirmation processing unit 242 instructs the EPS-ECU 8 to actually steer up to the read allowable steering angle while the vehicle 1 is stopped. At this time, the confirmation processing unit 242 gives an instruction to set the steering angular velocity to about half of the maximum angular velocity (for example, 360 [deg / s]). This is to prevent the EPS motor 9 from steering beyond the original allowable steering angle with momentum when steering at a large steering angular velocity, and the steering cannot 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 the actual steering angular velocity based on the signal input from the steering angular velocity sensor 42. If the read allowable steering angle is appropriate, the EPS motor 9 can steer to the allowable steering angle without slowing down the actual steering angular velocity. On the other hand, if the read allowable steering angle is not appropriate, the actual steering angular velocity is slowed down 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 determining the blunting (for example, an angular velocity of about half of the instructed steering angular velocity), and the read allowable steering angle is appropriate. Judge whether or not.

If the EPS motor 9 can steer to the permissible steering angle while the actual steering angular velocity remains higher than the threshold angular velocity, the confirmation processing unit 242 determines that the read permissible steering angle is appropriate, and determines that the permissible steering angle is appropriate. The angle is output to the orbit generation unit 243. On the other hand, if 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 at this time, the allowable steering angle table is based on the steering angle detected by the steering angle sensor 41. Read the allowable steering angle with reference to. For example, it is assumed that the number of passengers is determined to be one, and the allowable steering angle is read as 300 [deg] based on the allowable steering angle table of FIG. 2 (b). Then, even though it was instructed to actually steer up to 300 [deg], if the actual steering angular velocity becomes equal to or less than the threshold angular velocity at 210 [deg], the actual number of passengers is three. It can be inferred that it was. Therefore, the confirmation processing unit 242 reads out the allowable steering angle when the number of passengers is three, 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 trajectory creating unit 24 creates an ideal trajectory so 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 trajectory is created so that the steering angle does not become larger than 300 [deg]. The specific method for creating an ideal orbit is not limited.

The own vehicle position estimation unit 25 estimates the current position of the vehicle 1. The own vehicle position estimation unit 25 estimates the current position of the vehicle 1 from the detection signals sequentially input from the various sensors 4 with reference to the position of the vehicle 1 when the parking support is started. In the following, the estimated current position of the vehicle 1 will be referred to as an “estimated position”.

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

The image control unit 27 creates an image for parking support and displays it on the display 7. In the present embodiment, an image (see FIG. 6) in which a frame indicating the target parking position, a track indicating the ideal trajectory, and a stop line indicating the turning position are superimposed on the bird's-eye view image is displayed. Let me.

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

Next, the parking support process 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 start processing of the parking support processing. The process is executed at the start of the parking support process, and is executed, for example, when an operation signal instructing the start of the parking support is input from the operation device 5. It should be noted that the execution may be performed when there is an operation indicating an intention to park, such as when the R range (reverse range) is selected by the shift operation.

First, the position of the vehicle 1 at the start of parking support (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 bird's-eye view image creating unit 21 creates a bird's-eye view image (S3). Next, the target parking position is set (S4). Specifically, the parking frame detection unit 22 detects the 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 the detected parking frames as the target parking position. Information on the target parking position and direction (position and direction based on the start position) is stored. Then, the trajectory creation process is performed by the trajectory creation unit 24 (S5), and the start process is completed.

FIG. 3B is an example of a flowchart for explaining the trajectory creation process. The trajectory creation 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 status from the signal input from the seat sensor 44 (S11). Then, the allowable steering angle reference unit 241 refers to the allowable steering angle table based on the acquired information, and reads out the allowable steering angle set in the allowable steering angle table (S12).

Next, the confirmation processing unit 242 performs confirmation processing based on the read-out 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 or not the read allowable steering angle is appropriate (S14). The confirmation processing unit 242 determines that the read allowable steering angle is appropriate when the EPS motor 9 can steer to the allowable steering angle while the actual steering angular velocity remains higher than the threshold angular velocity (S14: YES). ), The allowable steering angle is output to the track generation unit 243. On the other hand, if 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), and the actual steering angle is actual. 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 out (S15) with reference to the allowable steering angle table, and the allowable steering angle is output to the trajectory 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 with respect to the start position.

FIG. 4 is a diagram for explaining an ideal trajectory when a target parking position that requires turning back is selected. In FIG. 4, it is assumed that the parking support process is started when the vehicle 1 is located at the point P1. The point P1 is, for example, the center position of the vehicle 1 (the same applies to the points P2 and P3).

FIG. 4A shows an ideal trajectory when the number of passengers is one. The parking support process start process is executed at the point P1, and the point P1 is set as the start position. Then, it is assumed that the parking frame indicated by the point P2 is set as the target parking position from the detected parking frame. When parking from the start position P1 to the target parking position P2, it is necessary to turn back, so the orbit L1 and the orbit L2 are created as ideal orbits. The orbit L1 is an ideal orbit from the start position P1 to the turning position P3, and the orbit L2 is an ideal orbit from the turning position P3 to the target parking position P2. In the present embodiment, when turning back is required for parking, a stop line K1 for indicating the turning back position is set. The ideal track composed of the track L1 and the track L2 is created in consideration of the allowable steering angle (see FIG. 2B) when the number of passengers is one. In FIG. 4A, an ideal trajectory is created so that the steering angle does not become larger than 300 [deg].

FIG. 4B shows an 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 track in FIG. 4 (b) is created in consideration of the allowable steering angle (see FIG. 2 (b)) when the number of passengers is four. In FIG. 4B, 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 requires two turns rather than one turn.

FIG. 5A is an example of a flowchart for explaining the iterative process of the parking support process. The process is repeated from the end of the start process (see FIG. 3A) until the parking support is interrupted (for example, when an operation signal instructing the end of the parking support is input from the operation device 5). Will be executed.

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

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. 5A.

First, it is determined whether or not the image data is input from each of the cameras 31 to 34 (S31). If it is not input (S31: NO), the screen display process is terminated. When input (S31: YES), the bird's-eye view image creating unit 21 creates a bird's-eye view image (S32). The created bird's-eye view image data is stored in an output buffer by the image control unit 27. Next, the display of the orbit is superimposed on the bird's-eye view image (S33). Specifically, the image control unit 27 creates an orbit after the estimated position based on the stored ideal orbit information and the estimated position information, and uses the image data of the created orbit as the information of the buffer for output. Superimpose. Next, the display of the frame is superimposed on the bird's-eye view image (S34). Specifically, the image control unit 27 creates a frame based on the stored target parking position and direction information and the estimated position information, and superimposes the image data of the created frame on the information of the output buffer. Let me. Next, the display of the stop line for turning back is superimposed on the bird's-eye view 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 outputs the image data of the created stop line to the buffer for output. Superimpose on information. Then, the image control unit 27 outputs the image data of the output buffer to the display 7, so that the bird's-eye view image on which the display of the trajectory, the frame, and the stop line is superimposed is displayed on the display screen of the display 7. (S36), the screen display process is terminated. Each time image data is input from each of the cameras 31 to 34, the image displayed on the display 7 is rewritten, so that the image is displayed on the display 7 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 support process is started, and is an image displayed on the display screen of the display 7 in the state of FIG. 4A. FIG. 6B is an image after the vehicle 1 has advanced along the track L1 for a while. These images are bird's-eye images in which the vehicle 1 is displayed in the center of the screen and facing upward on the screen. The orbits L1 and L2, the frame F1, and the stop line K1 are superimposed and displayed on these images. By looking at these images, the driver can recognize the positional relationship between the vehicle 1 and the frame F1 indicating the target parking position and the stop line K1 indicating the turning position, and the track that the vehicle 1 plans to follow. Can be recognized. The driver operates the accelerator and the brake to slowly advance the vehicle 1 until the tip of the vehicle 1 reaches the stop line K1. Since the steering angle is input from the parking support 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 need 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 vehicle 1. Therefore, the steering angle input from the parking support ECU 2 to the EPS-ECU 8 does not become a steering angle that the EPS motor 9 cannot steer. When the vehicle 1 reaches the turning position, the track L1 and the stop line K1 are not displayed. After selecting the R range (reverse range) by the shift operation, the driver operates the accelerator and the brake to slowly reverse the vehicle 1 until the vehicle 1 fits in the frame F1.

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

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

According to the present embodiment, the track creating 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. Allowable steering angle The allowable steering angle for each number of passengers is preset in the allowable steering angle table. Then, the trajectory creating unit 24 creates an ideal trajectory in consideration of the read allowable steering angle. The ideal track has a smaller turning angle because the allowable steering angle increases as the actual number of passengers decreases. Therefore, the parking support ECU 2 can create an ideal trajectory with as small a turn as possible according to the actual number of passengers. As a result, the parking support ECU 2 can propose an ideal trajectory with as few turns as possible. For example, the ideal orbits L1 and L2 shown in FIG. 4A when the number of passengers is one are smaller than the ideal orbits shown in FIG. 4B when the number of passengers is four. There is. In the case of FIG. 4A, since an ideal orbit with a small turn can be created, an orbit 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 support ECU 2 can prevent the ideal trajectory from being created based on an inappropriate allowable steering angle.

In the present embodiment, the case where the track creating unit 24 includes the confirmation processing unit 242 and the confirmation processing unit 242 confirms whether or not the allowable steering angle is appropriate has been described, but the present invention is limited to this. do not have. The trajectory creating unit 24 may not include the confirmation processing unit 242, and the trajectory generating unit 243 may create an ideal trajectory based on the allowable steering angle read by the allowable steering angle reference unit 241. In this case, the time required to create the ideal trajectory can be shortened.

Further, in the present embodiment, the case where the trajectory generation unit 243 creates an 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 to this. For example, after the allowable steering angle reference unit 241 reads out the allowable steering angle, the track generation unit 243 creates an ideal trajectory based on the allowable steering angle, and after the actual parking support is started by the iterative process, the confirmation processing unit The confirmation process according to 242 may be performed. In this case, if 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, the method for reading the allowable steering angle from the allowable steering angle table when the confirmation processing unit 242 determines that the allowable steering angle is not appropriate is not limited to the above. For example, in the allowable steering angle table, the allowable steering angle when the number of passengers is increased by one may be read out. In this case, the confirmation processing unit 242 may redetermine whether or not the read allowable steering angle is appropriate.

Further, in the present embodiment, the case where the seat sensor 44 detects only the presence or absence of seating of the seat by the pressure sensor has been described, but the present invention is not limited to this. For example, the seat sensor 44 may be able to detect the weight of a seated person with a pressure sensor. In this case, the actual steering axle load can be calculated. Therefore, if the allowable steering angle corresponding to the steering axle load is set in the allowable steering angle table, the trajectory creating unit 24 reads out the allowable steering angle corresponding to the actual steering axle load and creates an ideal trajectory. Can be done. Therefore, the parking support ECU 2 can create an ideal trajectory with as small a turn as possible according to the actual steering axle load. In this case, the calculated steering axle load corresponds to the "seating condition" of the present invention.

The parking support device according to the present invention is not limited to the above-described embodiment. The specific configuration of each part of the parking support device according to the present invention can be freely redesigned.

1: Car 2: Parking support ECU
21: Overhead image creation unit 22: Parking frame detection unit 23: Target parking position setting unit 24: Track creation unit 241: Allowable steering angle reference unit 242: Confirmation processing unit 243: Track generation unit 25: Own 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: Operating device 6: Speaker 7: Display 8: EPS-ECU
9: EPS motors L1, L2: Track K1: Stop line P1: Start position P2: Target parking position P3: Turning position F1: Frame

Claims (2)

A target parking position setting means for setting a target parking position for parking a car, and a target parking position setting means,
A track creation means for creating an ideal track, which is a track with as small a turn as possible from the position of the vehicle to the target parking position.
Guidance control means for driving a motor to automatically steer the vehicle along the ideal track, and
A storage unit that stores the correspondence between the seating status regarding the presence or absence of seating of each seat and the allowable steering angle, which is the maximum steering angle that the motor can steer when the vehicle is stopped.
Equipped with
The motor cannot perform automatic steering at the maximum steering angle, which is the maximum steering angle that can be steered by the steering mechanism of the vehicle, due to insufficient output torque when the maximum number of passengers are on board.
The trajectory creating means acquires the detection result of the seating condition detection unit that detects the seating condition, reads out the 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 support device characterized by that. The orbit creating means is
The motor is driven so as to steer at a predetermined steering angular velocity up to the read-out allowable steering angle.
When 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 support device according to claim 1.

Images