JP7413938B2 - parking assist device - Google Patents

Description

The present invention relates to a parking assist device.

Patent Document 1 listed below describes a method of steering the tires of a vehicle toward the edge of the lane at the end of parking so that the vehicle will stop even if it starts rolling in a parking situation on a slope. .

Special Publication No. 2017-507829

By turning the steerable wheels when parking, it is possible to prevent the vehicle from starting to move due to its own weight on a slope, or to stop the vehicle even if it starts moving. Whether it is safer to steer the steerable wheels toward the roadside or the opposite side depends on the situation in which the vehicle is parked.
The present invention has been made with attention to the above-mentioned problem, and an object of the present invention is to provide a parking assistance device that can automatically steer steered wheels in a steered direction depending on the parking situation.

In order to achieve the above object, a parking assistance device according to one aspect of the present invention includes a positioning unit that measures the current position of a vehicle, a parking determination unit that determines whether the vehicle is parked, and a parking determination unit that determines whether the vehicle is parked. a steering direction determining unit that determines whether to steer the steered wheels of the vehicle toward the road edge or toward the opposite side of the road edge based on the positioning information from the positioning unit when the determination is made; and a steering angle control unit that controls the steering angle of the steered wheels so that the steered wheels are steered in the steered direction determined by the steered direction determination unit.

According to the present invention, there is provided a parking assist device that can automatically steer steered wheels in a steered direction depending on the parking situation.

FIG. 1 is a configuration diagram showing an overview of an example of an electric power steering device according to an embodiment. (a) to (c) are explanatory diagrams of the operation of the electric power steering device when parking the vehicle on a slope. 3 is a block diagram of an example of a functional configuration of a control unit 30. FIG. It is a flow chart of an example of the parking assistance method of an embodiment.

Embodiments of the present invention will be described in detail with reference to the drawings.
Note that the embodiments of the present invention shown below exemplify devices and methods for embodying the technical idea of the present invention. is not limited to the following: The technical idea of the present invention can be modified in various ways within the technical scope defined by the claims.

(composition)
FIG. 1 shows a configuration example of an electric power steering (EPS) device according to an embodiment. A steering shaft (steering shaft, handle shaft) 2 of a steering handle 1 of a vehicle passes through a reduction gear (worm gear) 3 that constitutes a reduction mechanism, universal joints 4a and 4b, a pinion rack mechanism 5, tie rods 6a and 6b, and further It is connected to steered wheels 8L and 8R via hub units 7a and 7b. Hereinafter, the steered wheels 8L and 8R may be collectively referred to as "steered wheels 8."

The pinion rack mechanism 5 includes a pinion 5a connected to a pinion shaft to which a steering force is transmitted from a universal joint 4b, and a rack 5b that meshes with the pinion 5a. to convert it into a straight motion in the vehicle width direction.
The steering shaft 2 is provided with a torque sensor 10 that detects the steering torque Th. Further, the steering shaft 2 is provided with a steering angle sensor 11 that detects the steering angle θh of the steering handle 1.

Furthermore, the vehicle includes a vehicle speed sensor 12, a wheel speed sensor 13, a vehicle sensor 14, a positioning device 15, a map database (map DB) 16, an object detection sensor 17, a shift position sensor 18, and a mode switch ( mode SW) 19.
Vehicle speed sensor 12 detects vehicle speed Vv, which is the traveling speed of the vehicle. The wheel speed sensor 13 detects the wheel speed Vw of the steered wheel 8 and the remaining wheels. Note that the vehicle speed Vv may be determined based on the wheel speed Vw.

Vehicle sensor 14 detects vehicle behavior. The vehicle sensor 14 includes a 3-axis acceleration sensor (G sensor) that detects acceleration (including deceleration) in 3-axis directions of the vehicle, a gyro sensor that detects the angular velocity generated in the vehicle, and a yaw rate sensor that detects the yaw rate. good.
Note that the attitude of the vehicle, which will be described later, may be detected based on the behavior of the vehicle detected by the vehicle sensor 14. When the vehicle is stopped, the direction of the gravitational acceleration acting on the vehicle is: when the vehicle is horizontal, when the vehicle is facing upward, and when the vehicle is facing downward. different. That is, the attitude of the vehicle can be determined using the detected values of the three-axis acceleration sensor.
The positioning device 15 measures the current position of the vehicle. The positioning device 15 includes, for example, a global positioning system (GNSS) receiver, and measures the current position of the vehicle by receiving radio waves from a plurality of navigation satellites.

The GNSS receiver may be, for example, a Global Positioning System (GPS) receiver. Furthermore, the positioning device 15 may measure the current position of the vehicle using inertial navigation or odometry.
The positioning device 15 outputs positioning information indicating the measurement result of the current position of the vehicle. The positioning information may include altitude information of the vehicle and measurement results of the attitude of the vehicle (that is, the direction of the vehicle, the front-rear direction).
The positioning device 15 may detect position information of at least two locations of the vehicle. The positioning device 15 includes two antennas (not shown) that receive positioning signals, and each antenna can be placed at a separate location. For example, one antenna can be placed at a first position and the other antenna can be placed at a second position that is rearward of the vehicle from the first position. By arranging the antennas in this manner, the current positions of the first position and the second position can be respectively detected. Vehicle attitude information can be determined based on the current position of the first position and the current position of the second position. For example, if the altitude of the first position is greater than the altitude of the second position, it may be determined that the vehicle is pointing upwards. Also, for example, if the altitude of the first position is less than the altitude of the second position, it may be determined that the vehicle is facing downward.

A map database (map DB) 16 stores road map information for car navigation. High-precision map data suitable for automatic driving control may be stored. The map information includes road gradient information and regulation information of regulations (e.g., ordinances and laws) that apply regarding parking in a specific geographical area (e.g., region, region, state, province, country, etc.). Good too.

Rules that apply to parking include, for example, rules that require the wheels to be steered while parking on a slope (hereinafter sometimes referred to as "parking steering"), and rules that require drivers to turn their wheels while parking on a slope, and rules that require drivers to turn their wheels while parking on a slope, and those that require drivers to turn their wheels while parking on a slope (hereinafter sometimes referred to as ``parking steering''), and those that require vehicles to steer while parking on a slope. May include rules prohibiting parking.
Further, the map information may include altitude information indicating the altitude at each point.
Note that the map information and rule information may be acquired by wireless communication using a public mobile telephone network, vehicle-to-vehicle communication, road-to-vehicle communication, or satellite communication.

The object detection sensor 17 detects objects around the vehicle and the direction and distance to the objects. The object detection sensor 17 may be a distance measuring sensor such as a laser radar, a millimeter wave radar, a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), a camera, or the like.
The shift position sensor 18 detects the position of the shift lever (shift position).

The mode switch 19 is a switch operated by a vehicle occupant (for example, a driver) to turn on and off parking assist control using an electric power steering device.
Parking support control is control that automatically performs parking steering when parallel parking on a slope. Details of the parking assist control will be described later.

A motor 21 that generates a steering assist force for assisting the steering of the steering handle 1 is connected to the steering shaft 2 via a reduction gear 3 . Note that the means for applying the steering assist force is not limited to a motor, and various types of actuators can be used.
The EPS controller 20 is an electronic control unit (ECU) that controls the electric power steering device.

The EPS controller 20 calculates the current command value of the assist control command based on the steering torque Th detected by the torque sensor 10 and the vehicle speed Vv detected by the vehicle speed sensor 12, and performs compensation etc. on the current command value. The current supplied to the motor 21 is controlled based on the applied voltage control command value.
The rotation angle sensor 22 detects the rotation angle of the rotation shaft of the motor 21. The EPS controller 20 measures the steered angle θt of the steered wheels 8 based on the rotation angle detected by the rotation angle sensor 22.

The control unit 30 is an electronic control unit that executes parking assistance control using an electric power steering device. The control unit 30 may be a dedicated electronic control unit for parking assistance control, or may be a unit integrated with another electronic control unit (for example, the EPS controller 20) mounted on the vehicle.
The positioning device 15, the object detection sensor 17, the mode switch 19, the EPS controller 20, and the control unit 30 form the parking assist device of the embodiment. The positioning device 15 is an example of a "positioning unit" described in the claims.

The control unit 30 may include, for example, a computer including a processor and peripheral components such as a storage device. The processor may be, for example, a CPU (Central Processing Unit) or an MPU (Micro-Processing Unit).
The storage device may include any one of a semiconductor storage device, a magnetic storage device, and an optical storage device. The storage device may include memory such as a register, a cache memory, a ROM (Read Only Memory) used as a main storage device, and a RAM (Random Access Memory).
Further, the control unit 30 may be provided with a user interface (user I/F) 31 for presenting an auditory signal or a visual signal to the occupant. The control unit 30 can output a warning to the occupant via the user interface 31.

The functions of the control unit 30 described below are realized, for example, by a processor of the control unit 30 executing a computer program stored in a storage device.
Note that the control unit 30 may be formed of dedicated hardware for executing each information process described below.
For example, the control unit 30 may include a functional logic circuit set in a general-purpose semiconductor integrated circuit. For example, the control unit 30 may include a programmable logic device (PLD) such as a field-programmable gate array (FPGA).

Next, an overview of parking assistance control by the control unit 30 will be explained. Refer to FIGS. 2(a) to 2(c).
The control unit 30 acquires positioning information from the positioning device 15 when determining that the vehicle 40 is parked. Furthermore, the control unit 30 detects a curb 42 on the roadside 41 based on the output signal of the object detection sensor 17.

The control unit 30 determines whether the vehicle 40 is parked on an uphill slope or downhill based on the positioning information. In FIG. 2, the U direction indicates the upward direction of the slope, the D direction indicates the downward direction of the slope, the W direction indicates the sidewalk direction, and the R direction indicates the road side. FIG. 2(a) shows a case where the vehicle 40 is parked on a downhill slope, and FIG. 2(b) and FIG. 2(c) show a case where the vehicle 40 is parked on an uphill slope.
Here, an uphill slope refers to a slope where the height position in the direction in which the vehicle is traveling is higher than the height position in the opposite direction to the direction in which the vehicle is traveling. Further, a downhill slope refers to a slope where the height position in the direction in which the vehicle is traveling is lower than the height position in the opposite direction to the direction in which the vehicle is traveling.
The control unit 30 steers the steered wheels 8 toward the road edge 41 or toward the opposite side of the road edge 41 depending on whether the vehicle 40 is parked on an uphill slope or downhill. Decide whether to steer.

When the vehicle 40 is parked on a downhill slope, the steering direction is determined so that the steerable wheels 8 are steered toward the road edge 41 as shown in FIG. 2(a).
As a result, even if the occupant forgets to apply the parking brake, for example, the steered wheels 8 will come into contact with the roadside 41, thereby preventing the vehicle 40 from starting to move under its own weight, or even if the vehicle 40 starts moving, it can be stopped. .

On the other hand, when the vehicle 40 is parked on an uphill slope, the control unit 30 steers the steered wheels 8 toward the road edge 41 depending on whether there is a curb 42 on the road edge 41. It is determined whether to turn the steering wheel toward the opposite side of the road edge 41.
When there is a curb 42 on the road edge 41, the steering direction is determined so that the steered wheels 8 are steered toward the opposite side of the road edge 41, as shown in FIG. 2(b). Thereby, when the steered wheels 8 come into contact with the road edge 41, the vehicle 40 can be prevented from starting to move due to its own weight, or even if the vehicle 40 starts moving, it can be stopped.

On the other hand, if there is no curb 42 on the road edge 41, the steering direction is determined so that the steered wheels 8 are steered toward the road edge 41, as shown in FIG. 2(c).
Thereby, even if the vehicle 40 starts moving under its own weight, it can be prevented from moving toward the roadway.
The control unit 30 causes the EPS controller 20 to drive the motor 21 to steer the steered wheels 8 in the determined steered direction up to the target steered angle θd.
As described above, the vehicle 40 can be parked more safely on a slope by automatically steering the steered wheels 8 in the steered direction according to the parking situation. Furthermore, failure to turn the vehicle when parking can be prevented in geographical areas where there are rules requiring steering when parking on a slope.

Next, with reference to FIG. 3, the functions of the control unit 30 will be explained in detail. The control unit 30 receives vehicle speed Vv information, wheel speed Vw information, positioning information, map information, and shift position information from the vehicle speed sensor 12, wheel speed sensor 13, positioning device 15, map database 16, and shift position sensor 18, respectively. Load information.
Furthermore, the control unit 30 detects whether the mode switch 19 is turned on or off.

The control unit 30 also reads detection signals from the acceleration sensor, gyro sensor, and yaw rate sensor of the vehicle sensor 14.
Furthermore, the control unit 30 reads image signals of objects around the vehicle 40 from the camera of the object detection sensor 17, and reads distance measurement information of objects around the vehicle 40 from the distance measurement sensor.

The control unit 30 includes a parking determination section 50, a curb detection section 51, an availability determination section 52, a steering direction determination section 53, a steering angle determination section 54, a steering angle control section 55, and an engine control section. 56 and an alarm generation section 57.
The parking determination unit 50 determines whether the vehicle 40 is parked on the roadside 41 or not. Parking determination unit 50 determines that vehicle 40 is parked, for example, when vehicle speed Vv and wheel speed Vw are below a predetermined speed (eg, zero km/h) and the shift position is parking.

The parking determination unit 50 may determine whether the vehicle 40 is parked at the roadside 41 based on, for example, positioning information and map information. For example, the parking determination unit 50 may determine that the vehicle 40 has stopped at the road edge 41 when the distance between the vehicle 40 and the road edge 41 closest to the vehicle 40 is less than or equal to a threshold value.
For example, it may be determined whether the parking position of the vehicle 40 is at the roadside 41 based on image signals of objects around the vehicle 40. For example, the road edge 41 may be recognized by performing image recognition processing on image signals of objects around the vehicle 40.

The curb detection unit 51 detects a curb 42 located at a roadside 41. For example, the curb detection unit 51 may recognize the curb 42 on the roadside 41 by performing image recognition processing on image signals of objects around the vehicle 40.
The curb detection unit 51 detects the distance from the vehicle 40 to the curb 42 based on distance measurement information obtained by detecting an object recognized as the curb 42 through image recognition processing using a distance measurement sensor. Note that since the detection range of radar and LIDAR is narrow, if there is an object for which ranging information has been obtained, this object may be regarded as the curbstone 42.

When the parking determination unit 50 determines that the vehicle 40 is parked on the roadside 41, the availability determination unit 52 determines whether or not to execute parking assistance control, that is, whether to execute steering when parking on a slope. do.
For example, the availability determining unit 52 determines to execute the parking assist control when the vehicle 40 is parked on a slope and the mode switch 19 is on. The permission determination unit 52 may permit parking assistance control when the slope of the parking position of the vehicle 40 is equal to or greater than a threshold value.

The availability determination unit 52 may determine the slope and its inclination based on, for example, positioning information and slope information of map information.
Further, for example, the availability determining unit 52 may determine whether the vehicle is on a slope based on a change in the altitude information of the positioning information until the vehicle 40 is parked. The availability determining unit 52 may determine the inclination of the slope based on changes in altitude information and changes in the horizontal position until the vehicle 40 is parked.
For example, the availability determining unit 52 may determine a slope or its inclination based on a detection signal from an acceleration sensor or a yaw rate sensor of the vehicle sensor 14.

For example, the availability determination unit 52 may determine that parking assistance control is not performed in accordance with the rules applied to parking at the parking position, based on the positioning information and the rule information of the map information.
For example, the availability determination unit 52 determines that parking assistance control is to be performed when steering when parking on a slope is required at the parking position, and determines that parking assistance control is not to be performed if it is not required. good.

Furthermore, if parking is prohibited at the parking position, the permission/impossibility determination unit 52 may determine that the parking assistance control is not performed.
For example, the rule information in the map information may include information on the colors of curbs 42 and signs that prohibit parking in a particular geographic area (eg, region, area, state, province, country, etc.).
The permission determining unit 52 may detect the color of the curb 42 based on the image signal of the curb 42, and determine whether parking is prohibited at the current position of the vehicle 40 based on the color of the curb 42. Further, the permission determining unit 52 may recognize a sign from an image signal around the roadside 41 and determine whether parking is prohibited.

When the availability determining unit 52 determines to perform parking assistance control, the steering direction determining unit 53 steers the steered wheels 8 toward the road edge 41 or toward the opposite side of the road edge 41. is determined based on the detection result of the curb 42 by the curb detection unit 51 and the positioning information.
Specifically, the steering direction determining unit 53 determines whether the vehicle 40 is parked on an uphill slope or downhill based on the positioning information.

When the vehicle 40 is parked on a downhill slope, the steering direction determination unit 53 steers the steered wheels 8 toward the road edge 41, as shown in FIG. 2(a). Determine direction.
Furthermore, when the vehicle 40 is parked on an uphill slope and there is a curb 42 on the road edge 41, the steered wheels 8 are turned toward the opposite side of the road edge 41, as shown in FIG. 2(b). Determine the steering direction so as to turn the steering wheel.
Further, if the vehicle 40 is parked on an uphill slope and there is no curb 42 on the road edge 41, the steered wheels 8 are steered toward the road edge 41 as shown in FIG. 2(c). Determine the steering direction.

The steering direction determining unit 53 determines whether the vehicle 40 is parked on an uphill slope or downhill based on the positioning information.
For example, the steering direction determination unit 53 may make the determination based on positioning information and slope information of map information. For example, the steering direction determination unit 53 determines the orientation of the vehicle 40 (i.e., the forward direction of the vehicle 40) based on changes in positioning information (i.e., position changes) until the vehicle 40 is parked, and determines the orientation of the vehicle 40 and the slope of the vehicle 40. Based on the information, it may be determined whether the vehicle 40 is parked on an uphill slope or downhill.

The steering direction determination unit 53 may determine whether the vehicle 40 is parked on an uphill slope or downhill based on the attitude information and slope information of the vehicle 40 included in the positioning information.
For example, the steering direction determining unit 53 may determine whether the vehicle 40 is parked on an uphill slope or downhill based on changes in altitude information of the positioning information until the vehicle 40 is parked. good.
For example, the steering direction determination unit 53 may determine whether the vehicle 40 is parked on an uphill slope or a downhill slope based on a detection signal from an acceleration sensor or a yaw rate sensor of the vehicle sensor 14. .

When the availability determining unit 52 determines to perform parking assistance control, the turning angle determining unit 54 determines the absolute value of the target turning angle θd for turning the steered wheels 8 in the parking assistance control.
At this time, if the tires of the steered wheels 8 hit the curbs 42, there is a risk that the tires will be damaged.
Moreover, if the steering angle reaches the end stop position, there is a risk that the pinion rack mechanism 5 will be damaged. The end contact position is a position where the absolute value of the steering angle θt cannot be increased any further, and is, for example, a position where the rack shaft of the pinion rack mechanism 5 reaches the stroke end.

Therefore, the turning angle determining unit 54 calculates the absolute value of the maximum turning angle at which the turning wheels on the road edge 41 side do not come into contact with the curb 42, based on the position information of the curb 42 detected by the curb detection unit 51.
The steering angle determination unit 54 determines the smaller of the absolute value of the calculated maximum steering angle and the set steering angle preset according to the end stop position as the absolute value of the target steering angle θd. do. This set turning angle may be, for example, a value obtained by subtracting a predetermined margin angle from the absolute value of the turning angle at the end rest position.

The steering angle control unit 55 outputs a steering command to the EPS controller 20 to drive the motor 21 so that the steered wheels 8 are steered, and changes the steered angle θt of the steered wheels 8 to the target steered angle θd. do.
Specifically, the steering angle control unit 55 acquires the steering angle θt of the steered wheels 8, which is measured based on the rotation angle of the motor 21 detected by the rotation angle sensor 22, from the EPS controller 20.

The steered angle control section 55 controls the steered wheels 8 to be steered in the steered direction determined by the steered direction determination section 53, and the absolute value of the steered angle θt of the steered wheels 8 to be determined by the steered angle determination section 54. The steering angle θt is controlled so that it becomes the absolute value of the determined target steering angle θd.
Note that the steering angle control section 55 may calculate the steering angle θt based on the steering angle θh detected by the steering angle sensor 11.

The turning angle control unit 55 may start turning the steered wheels 8, for example, at any of the following timings (A) to (D).
(A) After a predetermined period of time has passed since the shift position was changed to Park (B) When the ignition switch is turned off (C) When the occupant exits the vehicle and receives a key lock command (D) When the shift position is changed to Park The point in time when the crew member performs the prescribed operation to steer the rudder.

Note that if the torque sensor 10 detects an excessive steering torque Th while the steering angle is changing due to parking assist control, there is a possibility that the occupant is interfering with the steering wheel 1.
Therefore, when the torque sensor 10 detects an excessive steering torque Th during the steering angle control in parking assistance control (for example, when the absolute value of the steering torque Th is equal to or greater than a threshold value), the steering angle control unit 55 Parking assistance control may also be canceled. In this case, the steering angle control section 55 may return the steering angle of the steered wheels 8 to the angle before executing the parking assist control. Alternatively, it may be returned to the neutral position.

Furthermore, when the parking of the vehicle 40 is completed (that is, when the engine of the vehicle 40 is restarted or the ignition switch of the vehicle 40 is changed from OFF to ON), the steering angle control unit 55 returns to the neutral position. The turning angle of the turning wheels 8 may be controlled so that the turning angle of the turning wheels 8 is as follows.
The start timing of the control to return the steered angle of the steered wheels 8 to the neutral position is, for example, when the engine is restarted, when the ignition switch of the vehicle 40 is changed from off to on, or when the shift lever or brake pedal is operated. This may be the time when some kind of steering by the occupant is detected, and the user may arbitrarily set whether to return at any of these timings.

Note that instead of the steering angle control unit 55 controlling the steering angle, the EPS controller 20 may control the steering angle in parking assist control. In this case, the control unit 30 outputs a steering command signal that includes information on the steering direction determined by the steering direction determination section 53 and information on the absolute value of the target steering angle θd determined by the steering angle determination section 54. may be output to the EPS controller 20. The EPS controller 20 steers the steered wheels 8 in the steered direction included in the steered command signal, and the absolute value of the steered angle θt of the steered wheels 8 becomes the steered angle included in the steered command signal. The steering angle may be controlled as follows.

Further, steering of the steered wheels 8 by the motor 21 involves power consumption of a battery mounted on the vehicle 40. Therefore, even if the ignition switch of the vehicle 40 is turned off, the engine control unit 56 does not operate the engine of the vehicle 40 until the parking assist control is completed (that is, until the turning of the steered wheels 8 is completed). Stopping may be prohibited (ie, the engine of vehicle 40 may continue to operate).

Note that depending on the remaining capacity (SoC: State of Charge) of the vehicle-mounted battery, if it is sufficiently charged, the steered wheels 8 may be steered while the engine is stopped. For this reason, the engine control unit 56 prohibits the engine stop of the vehicle 40 until the parking assistance control is completed when the remaining capacity of the on-board battery is less than the threshold value, and provides parking assistance when the remaining capacity of the on-board battery is equal to or higher than the threshold value. Engine stop during control may be permitted.

The warning generation unit 57 generates a warning and outputs it from the user interface 31 when performing parking assistance control.
For example, a warning may be generated to notify the occupant that the steering wheel 1 will rotate in conjunction with parking assist control. This can prevent interference between the rotating steering handle 1 and the occupant. For example, the alarm generation unit 57 determines that the occupant is in contact with the steering wheel 1 when the absolute value of the steering torque Th detected by the torque sensor 10 is greater than or equal to a threshold value, and prevents the steering wheel 1 from rotating. An alert may be generated to notify the user.

For example, the warning generation unit 57 generates a warning to notify the occupant that the vehicle 40 is too close to the curb 42 and that steering during parking cannot be performed in order to avoid contact between the tires and the curb 42. Good too. Further, since the absolute value of the maximum steering angle at which the steered wheels do not come into contact with the curb 42 is smaller than the predetermined lower limit value and the target steered angle θd is less than the lower limit value, the steered wheels 8 cannot be sufficiently steered. An alert may be generated to notify the occupants.
For example, when the object detection sensor 17 detects an object (person or object) outside the vehicle existing around the steered wheel 8, the alarm generation unit 57 prevents the steered wheel 8 from interfering with this object. In order to prevent this, an alarm may be generated to notify the occupant that the steered wheels 8 are being steered or that an object is present near the steered wheels 8.

For example, the warning generation unit 57 may generate a warning to inform the occupant that after the steering angle of the steered wheels 8 changes due to parking assistance control, operations to move the vehicle 40 forward or to update the vehicle 40 are prohibited.
For example, the warning generation unit 57 may not execute parking assistance control because of a rule prohibiting parking on the roadside, or may not execute parking assistance control because turning when parking on a slope is not required. An alert may be generated to notify the occupants.

Although the case where the parking assist device of the present invention is implemented in a vehicle equipped with an electric power steering device has been described above, the present invention is not limited to this. The parking assist device of the present invention can be realized as long as it has an actuator that can steer steerable wheels, a positioning function, and a curb detection function.
For example, instead of an electric power steering device, a steering mechanism (FFA: Force Feedback Actuator, steering reaction force generating device) that accepts steering operations by the driver, and a steering mechanism (RWA: Road Wheel Actuator, tire steering device) that steers wheels can be used. The parking assist device of the present invention may be implemented in a vehicle equipped with a steer-by-wire (SBW) type steering device in which the steering device and the steering device are mechanically separated.

(motion)
Next, parking assistance control by the electric power steering device of the embodiment will be explained. See FIG. 4.
In step S1, the parking determination unit 50 determines whether the vehicle 40 is parked on the roadside 41. When the vehicle 40 is parked on the roadside 41 (step S1: Y), the process proceeds to step S2. If the vehicle 40 is not parked on the roadside 41 (step S1: N), the process ends.

In step S2, the availability determination unit 52 determines whether or not to execute parking assistance control. If parking assistance control is to be executed (step S2: Y), the process proceeds to step S3. If parking assistance control is not executed (step S2: N), the process ends.
In step S3, the positioning device 15 measures the current position of the vehicle 40. In step S4, the control unit 30 reads map information around the current location of the vehicle 40 from the map database 16.

In step S5, the curb detection unit 51 detects the presence or absence of a curb 42 on the roadside 41.
In step S6, the steering direction determination unit 53 steers the steered wheels 8 toward the road edge 41 or to the opposite side of the road edge 41 based on the detection result of the curb 42 by the curb detection unit 51 and the positioning information. Decide whether to steer towards.
In step S7, the turning angle determining unit 54 determines the absolute value of the target turning angle θd for turning the turning wheels 8 in parking assist control.

In step S<b>8 , the warning generation unit 57 generates a warning associated with parking assistance control as necessary, and outputs it from the user interface 31 .
In step S9, the steered angle control section 55 steers the steered wheels 8 in the steered direction determined by the steered direction determination section 53, and determines that the absolute value of the steered angle θt of the steered wheels 8 determines the steered angle. The motor 21 is rotated so that the absolute value of the target steering angle θd determined by the unit 54 is achieved.

In step S10, the steering angle control unit 55 determines whether the torque sensor 10 has detected excessive steering torque Th. If excessive steering torque Th is detected (step S10: Y), the process proceeds to step S11. If excessive steering torque Th is not detected (step S10: N), the process proceeds to step S12.
In step S11, the steered angle control section 55 cancels the parking assist control and returns the steered angle θt of the steered wheels 8 to the angle before executing the parking assist control. Or return it to the neutral position. After that, the process ends.

In step S12, the steering angle control unit 55 determines whether or not the parking steering is completed. That is, the steered wheels 8 are steered in the steered direction determined by the steered direction determination unit 53, and the absolute value of the steered angle θt of the steered wheels 8 becomes the target steered angle determined by the steered angle determination unit 54. It is determined whether the absolute value of θd has been reached.
If the steering during parking is not completed (step S12: N), the process returns to step S9. If the parking steering is completed (step S12: Y), the process ends.

(Effects of embodiment)
(1) The parking support device includes a positioning device 15 that measures the current position of the vehicle 40, a parking determination unit 50 that determines whether the vehicle 40 is parked, and a parking determination unit 50 that determines whether the vehicle 40 is parked. a steering direction determination unit 53 that determines whether to steer the steered wheels of 40 toward the road edge 41 or toward the opposite side of the road edge 41 based on positioning information from the positioning unit; A steering angle control section 55 is provided that controls the steering angle of the steered wheels 8 so that the steered wheels 8 are steered in the steered direction determined by the steered direction determination section 53.

Thereby, the steered wheels 8 can be automatically steered in the steered direction according to the parking situation. The vehicle 40 can be parked more safely on a slope by automatically steering the steered wheels 8 in the steered direction according to the parking situation. Furthermore, failure to turn the vehicle when parking can be prevented in geographical areas where there are rules requiring steering when parking on a slope.

(2) The steering direction determining unit 53 determines whether the vehicle 40 is parked on an uphill slope or a downhill slope based on the positioning information from the positioning device 15, and determines whether the vehicle 40 is parked on an uphill slope. The steering direction may be determined depending on whether the vehicle is parked on a downhill slope or parked on a downhill slope. The steering direction determination unit 53 may further determine the steering direction depending on whether there is a curb at the roadside.
This makes it possible to determine the steering direction depending on the parking situation.

(3) The steering direction determination unit 53 determines whether the vehicle 40 is parked on an uphill slope or a downhill slope based on the change in the position of the vehicle 40 until the vehicle 40 is parked and the map information. You may do so.
The steering direction determining unit 53 may determine whether the vehicle 40 is parked on an uphill slope or downhill based on the change in altitude of the vehicle 40 until the vehicle 40 is parked.
The steering direction determining unit 53 may determine whether the vehicle 40 is parked on an uphill slope or downhill based on posture information representing the posture of the vehicle 40 and map information. The attitude information may be detected by the vehicle sensor 14 that detects the behavior of the vehicle 40, or may be detected by the positioning device 15.
Thereby, it can be determined whether the vehicle 40 is parked on an uphill slope or on a downhill slope.

(4) The vehicle may further include a propriety determination unit 52 that determines whether or not the steered angle control unit 55 can control the steered angle of the steered wheels 8 based on the positioning information and the map information. This makes it possible to avoid unnecessary execution of parking assist control on a slope where steering during parking is not necessary or in a section where parking is prohibited.
For example, the feasibility determining unit 52 determines whether or not the steering angle control unit 55 can control the turning angle of the steered wheels 8, depending on the color of a roadside curb or the recognition result of a sign provided at the roadside. It's fine.

(5) A curb detection unit 51 that detects the position of the curb 42 on the roadside 41 and a maximum steering angle at which the steered wheels 8 do not come into contact with the curb 42 or a preset steering angle, whichever is smaller. A steering angle determination unit 54 that determines the target steering angle θd may be included. The steered angle control unit 55 may control the steered angle of the steered wheels 8 so as to reach the target steered angle θd. Thereby, it is possible to prevent damage to the steered wheels 8 and the steered mechanism due to the parking assist control.

(6) The engine control unit 56 may further include an engine control unit 56 that prohibits the engine of the vehicle 40 from stopping until the control of the steered wheels 8 by the steering angle control unit 55 is completed.
This can prevent the remaining capacity of the vehicle battery from decreasing.
(7) The steering angle control unit 55 determines whether the engine of the vehicle 40 is restarted or the ignition switch of the vehicle 40 is turned on after the steered wheels 8 are steered in the steering direction determined by the steering direction determination unit 53. The steering angle of the steered wheels 8 may be controlled so that the steering wheel 8 is in the neutral position when it changes from off to on.
Thereby, when the vehicle 40 is restarted after parking, the effort of the occupant to return the steering wheel 1 to the position can be saved.

DESCRIPTION OF SYMBOLS 1... Steering handle, 2... Steering shaft, 3... Reduction gear, 4a, 4b... Universal joint, 5... Pinion rack mechanism, 5a... Pinion, 5b... Rack, 6a, 6b... Tie rod, 7a, 7b... Hub unit, 8L, 8R... Steered wheel, 10... Torque sensor, 11... Steering angle sensor, 12... Vehicle speed sensor, 13... Wheel speed sensor, 14... Vehicle sensor, 15... Positioning device, 16... Map database, 17... Object detection sensor, 18... Shift position sensor, 19... Mode switch, 20... EPS controller, 21... Motor, 22... Rotation angle sensor, 30... Control unit, 31... User interface, 50... Parking determination section, 51... Curb detection section, 52... Possibility determination section, 53... Turning direction determining section, 54... Turning angle determining section, 55... Turning angle control section, 56... Engine control section, 57... Warning generation section

Claims (12)

a positioning unit that measures the current position of the vehicle;
a parking determination unit that determines whether the vehicle is parked;
When it is determined that the vehicle is parked, it is determined based on the positioning information from the positioning unit whether the steered wheels of the vehicle are to be steered toward a road edge or toward the opposite side of the road edge. a steering direction determination unit that determines based on the steering direction;
a steered angle control unit that controls a steered angle of the steered wheels so that the steered wheels are steered in the steered direction determined by the steered direction determination unit;
Equipped with
The steering direction determination unit steers the vehicle toward the opposite side of the road edge when there is a curb at the road edge and the vehicle is parked on an uphill slope, and when there is no curb at the road edge. and when the vehicle is parked on an uphill slope, the parking assist device determines the steering direction so as to steer the vehicle toward the opposite side of the roadway and toward the end of the road . The steering direction determining unit includes:
Determining whether the vehicle is parked on an uphill slope or downhill based on positioning information from the positioning unit,
determining the steering direction depending on whether the vehicle is parked on an uphill slope or downhill;
The parking assist device according to claim 1, characterized in that: The steering direction determining unit determines whether the vehicle is parked on an uphill slope or a downhill slope based on a change in the position of the vehicle until the vehicle is parked and map information. The parking assist device according to claim 2. The steering direction determination unit determines whether the vehicle is parked on an uphill slope or downhill based on a change in altitude of the vehicle until the vehicle is parked. The parking assistance device according to item 2. The steering direction determining unit determines whether the vehicle is parked on an uphill slope or downhill based on posture information representing a posture of the vehicle and map information. The parking assistance device according to item 2. 6. The parking assist device according to claim 5, wherein the posture information is detected by a vehicle sensor that detects behavior of the vehicle. The parking assistance device according to claim 5, wherein the posture information is detected by the positioning section. Any one of claims 1 to 7 , further comprising a propriety determination unit that determines whether or not the steering angle control unit can control the steering angle of the steered wheels based on the positioning information and map information. The parking assistance device according to item (1). The availability determination unit determines whether or not the steering angle control unit can control the steering angle of the steered wheels, depending on the color of the curb at the roadside or the recognition result of a sign provided at the roadside. 9. The parking assist device according to claim 8 . a curb detection unit that detects the position of the roadside curb;
a steering angle determination unit that determines the smaller of a maximum steering angle at which the steered wheels do not contact the curb or a preset steering angle, whichever is smaller, as a target steering angle,
The parking assist device according to any one of claims 1 to 9 , wherein the steering angle control section controls the steering angle of the steered wheels so that the steering angle becomes the target steering angle. The vehicle according to any one of claims 1 to 10 , further comprising an engine control unit that prohibits the engine of the vehicle from stopping until the steering angle control unit completes control of the steered wheels. parking assist device. The steering angle control unit is configured to restart the engine of the vehicle or turn the ignition switch of the vehicle from OFF to ON after the steered wheels are steered in the steering direction determined by the steering direction determination unit. 12. The parking assist device according to claim 1, wherein the steering angle of the steered wheels is controlled so that the steered wheels are at a neutral position when the steering wheel changes to a neutral position.

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