JP2009161082A - Vehicle parking support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable parking without causing a deviation by a change in the rotational center, when deviating from a target line in rotation around the center set in response to front-rear spaces in the entering direction of a vehicle. <P>SOLUTION: When own vehicle tries to deviate from a target parking space PA in a rear target line in the vehicle entering direction when rotating the own vehicle around the center O1, the rotational center O1 is changed to O2 moved in the inverse direction of the moving direction of a deviated vehicle part. That is, a steering angle of respective wheels is changed so that the intersection O2 between a line β provided by offsetting a line α parallel to a vehicle side target line SL by passing through the deviated vehicle part in the direction for going away from the target line SL so that the own vehicle does not go over the target line SL in rotation and a line γ provided by offsetting a front target line FL in the vehicle entering direction backward in the vehicle entering direction so that the own vehicle does not go over the front target line FL in the vehicle entering direction in rotation, becomes the new rotational center of the own vehicle, to be set as the final parking position while rotating the own vehicle around the intersection O2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention operates when parking a vehicle such as a four-wheel steering vehicle capable of individually steering each wheel, or an in-wheel motor type electric vehicle in which each wheel is driven by an individual built-in motor and individually steerable. The present invention relates to a parking assist device for a vehicle that operates to assist a person.

  A vehicle that can individually steer each wheel as described above can set the rotation center (turning center) when viewed from above the vehicle to a position far from the own vehicle as in a two-wheel steering vehicle. Needless to say, the vehicle can be steered such that the center of rotation (turning) of the vehicle is located in the own vehicle area, which is particularly advantageous when parking in parallel in a narrow space.

By the way, when this type of vehicle is parked, since each vehicle is steered individually, a complicated movement of the vehicle occurs. Therefore, a parking assist device that assists the driver during parking is necessary.
As a parking assist device for this type of vehicle, a device as described in Patent Document 1, for example, has been proposed.

This parking assist device steers each wheel individually so as to eliminate the inner wheel difference and the outer wheel difference when guiding the vehicle at the time of parking, thereby avoiding the difficulty of vehicle guidance calculation due to the inner and outer wheel differences. This is intended to simplify the vehicle guidance calculation.
JP 2000-128008 A

However, the above-described conventional parking assistance device merely steers each wheel so that there is no difference between the inner and outer wheels, which complicates the vehicle guidance calculation. It intends to assist the parking by the guidance of the vehicle based on.
For this reason, there is a problem that complicated and troublesome trajectory calculation and precise vehicle guidance based on this are indispensable, and obstacles are detected during parking operation, and vehicle guidance according to the calculation trajectory is parked. When the situation cannot be completed, it is troublesome that the trajectory calculation must be performed again from the beginning, and the parking must be performed again by guiding the vehicle based on the calculation.

In the case of a vehicle in which each wheel can be steered individually, the present invention can arbitrarily set the center of rotation when viewed from above the vehicle by the individual steering of the wheel. From the viewpoint that it is possible to realize parking assistance that does not need to rely on precise vehicle guidance based on this,
Further, in the case of a vehicle in which each wheel can be steered individually, even if it is found that the vehicle deviates from the target parking space during parking operation, the vehicle rotation center is changed (moved) by individual steering of each wheel at that time. Based on the fact that the vehicle's movement trajectory after that can be made such that it does not deviate from the parking space,
It aims at proposing the parking assistance apparatus of the vehicle which actualized these ideas and implement | achieved said problem solution.

For this purpose, the parking assistance device for a vehicle according to the present invention is configured as described in claim 1.
First, the vehicle which is the premise of the present invention can change the steering angle of each wheel individually.

The parking assist device of the present invention is a vehicle of the above type,
Target parking space setting means for automatically setting the target parking space according to the driver's driving operation or by the driver according to a command;
Deviation determination means for determining whether the vehicle deviates from the target parking space set by the means;
When it is determined that the vehicle departs from the target parking space by the means, the rotation center of the vehicle changes from the rotation center of the vehicle based on the current steering angle of each wheel to a direction opposite to the moving direction of the departure vehicle part. It is characterized by a configuration comprising own vehicle rotation center changing means for changing the steering angle of each wheel so as to move.

In the parking assist device according to the present invention, when it is determined that the host vehicle departs from the target parking space, the center of rotation of the host vehicle deviates from the center of rotation of the vehicle based on the current steering angle of each wheel. Because it is a configuration that changes the steering angle of each wheel to move in the direction opposite to the moving direction of the part,
Even if it is known that the vehicle deviates from the target parking space during the parking operation, the steering angle of each wheel that changes (moves) the vehicle rotation center in the direction opposite to the moving direction of the vehicle part deviating as described above at that time As a result of the change, the subsequent movement trajectory of the vehicle can be made so as not to deviate from the target parking space.

Conventionally, when it was found that the vehicle departed from the target parking space during parking operation, it was troublesome to perform the vehicle trajectory calculation from the beginning, and to perform parking again by guiding the vehicle based on this. ,
According to the present invention, when the departure from the target parking space is found, the departure can be avoided only by changing (moving) the vehicle rotation center by changing the steering angle of each wheel. It is possible to realize the excellent parking support by avoiding the above trouble that the vehicle must be redone from the beginning and the parking must be redone by guiding the vehicle based on this.

  In addition, according to the present invention, the above-described excellent parking assistance can be realized simply by setting the center of rotation of the vehicle by individual steering of each wheel. There is no need to resort to precise vehicle guidance based, which is a great advantage.

Hereinafter, embodiments of the present invention will be described in detail based on examples shown in the drawings.
FIG. 1 shows a steering control system for an electric vehicle provided with a parking assist apparatus according to an embodiment of the present invention, wherein 1L and 1R are left and right front wheels, and 2L and 2R are left and right rear wheels, respectively.

The left and right front wheels 1L and 1R can be individually controlled by the steering actuators 3L and 3R, and the left and right rear wheels 2L and 2R can also be individually controlled by the steering actuators 4L and 4R.
Also, the left and right front wheels 1L and 1R and the left and right rear wheels 2L and 2R are individually driven by a so-called in-wheel motor (not shown) built in each wheel to electrically drive the vehicle.

Reference numeral 5 denotes a vehicle body in which the left and right front wheels 1L and 1R and the left and right rear wheels 2L and 2R are suspended, and a controller 6 for calculating a steering angle command value to the steering actuators 3L and 3R and the steering actuators 4L and 4R as described later. Installed in 5.
Further, a camera (or a distance sensor for measuring the distance to the obstacle) 7L, 7R, 8L, 8R for confirming the surrounding situation of the own vehicle when setting the target parking space is attached to the vehicle body 5.

Cameras (or distance sensors that measure the distance to the obstacles) 7L and 7R are placed at the left and right corners of the front of the vehicle body 5 to check the vehicle front and side conditions, The distance to the obstacle on the side of the vehicle shall be measured, and the cameras (or distance sensors for measuring the distance to the obstacle) 8L and 8R are arranged at the left and right corners of the rear part of the vehicle body 5 to The surrounding situation on the side of the vehicle is confirmed, and the distance to the obstacle at the rear and side of the vehicle is measured, and corresponding information is input to the controller 6.
Therefore, the cameras (or distance sensors for measuring the distance to the obstacle) 7L, 7R, 8L, 8R correspond to the obstacle detection means and the distance detection means in the present invention.

The vehicle body 5 is further equipped with a monitor 9 for allowing the driver to indicate the target parking space on the screen, and a parking assist switch 10 is provided near the steering wheel 10.
The parking assistance switch 11 is turned on when the driver wants to enter the place where the driver wants to park and starts the parking assistance, and is turned off when the parking is finished. A parking assistance start signal is sent to 6, and parking assistance by the controller 6 is started.

Hereinafter, the parking support control executed by the controller 6 will be described based on the flowchart shown in FIG.
The control program in FIG. 2 is started when the engine is turned on when the engine ignition switch is turned on, and thereafter repeatedly executed until the engine is stopped when the engine ignition switch is turned off.

In step S11, it is determined whether the parking assistance switch 11 is ON or OFF, and it is checked whether or not the driver is driving in a parking area for which parking assistance is desired.
While the parking assistance switch 11 is OFF, the control is returned to the original state, and the driver turns on the parking assistance switch 11 and waits until it desires parking assistance.

The driver enters the place where the vehicle is to be parked, and when the driver wishes to start parking assistance, the driver turns on the parking assistance switch 11 and commands the parking assistance.
The approach direction when approaching the place where the host vehicle is to be parked may be approach by advance of the host vehicle or approach by march.
When it is determined in step S11 that the parking assist switch 11 is ON, control proceeds from step S11 to step S12, and in this step S12, the target parking space is set as follows.

This step S12 corresponds to the target parking space setting means in the present invention, and in setting the target parking space, first, an obstacle on the side of the own vehicle is detected by the cameras 7L, 7R, 8L, 8R, and the detected side The obstacle is displayed on the monitor 9 together with the own vehicle, and the driver sets the vehicle side target line SL of the target parking space on the monitor 9.
An example of the vehicle side target line SL on the monitor 9 at this time is shown in FIGS. 3 and 6 together with a front other vehicle in front of the vehicle approach direction and a rear other vehicle in the rear of the vehicle entrance direction.

The vehicle side target line SL may be automatically set as follows instead of being set by the driver as described above.
That is, the distance sensor 7L, 7R, 8L, 8R detects the distance to the obstacle on the side of the vehicle, and the vehicle side target line SL of the target parking space based on the detected distance to the side obstacle. Is automatically set as illustrated in FIGS.

  Further, in step S12 of FIG. 2, the forward target in the vehicle traveling direction is exemplified as shown in FIGS. 3 and 6 based on the vehicle side target line SL set by the driver or automatically set as described above. A line FL and a vehicle target direction rear target line RL are set.

  In setting the target lines FL and RL, obstacles (other vehicles in FIGS. 3 and 6) in front of the vehicle in the approach direction and behind the approach direction are detected by the cameras 7L, 7R, 8L, and 8R and detected by the means. 3 and 6 are displayed on the monitor 9 together with the host vehicle in the approach direction forward obstacle and the approach direction rear obstacle, and the driver can display the front target line FL in the vehicle entrance direction of the target parking space PA on the monitor 9 and A vehicle target direction rear target line RL is set.

The setting of the vehicle approach direction front target line FL and the vehicle approach direction rear target line RL may be automatically performed as follows instead of being performed by the driver as described above.
That is, the line that is orthogonal to the vehicle side target line SL while passing through the front direction of the host vehicle and the rearmost direction of the approach direction, respectively, is the vehicle target direction front target line FL and the vehicle target direction rear target line RL, or
The distance to the obstacle in the front direction and the rear direction of the vehicle is detected by the distance sensors 7L, 7R, 8L, 8R, and based on the distance to the obstacle in the front direction and the rear direction detected by the means. The vehicle approach direction front target line FL and the vehicle approach direction rear target line RL may be automatically set.

  In step S12, a space surrounded by the vehicle side target line SL set as described above, the vehicle approach direction front target line FL, and the vehicle approach direction rear target line RL is shown in FIGS. The target parking space PA is defined as follows, which contributes to the following parking support control.

In step S13, the distance between the front and rear target lines (target parking space length) between the vehicle approach direction front target line FL and the vehicle approach direction rear target line RL is based on the diagonal dimension when viewed from above the host vehicle. It is checked whether it is the target parking space length that can park the own vehicle according to whether it is larger.
When it is determined in step S13 that the distance between the front and rear target lines (target parking space length) is not larger than the diagonal dimension of the own vehicle (not the target parking space length that can park the own vehicle), in step S14, the monitor 9 A warning “Insufficient parking space length (no parking)” is displayed above to make the driver recognize this.

  At this time, the warning “Insufficient parking space (parking not possible)” is not displayed on the monitor 9, and the distance between the vehicle approach direction front target line FL and the vehicle approach direction rear target line RL increases. If the distance between the vehicle approach direction front target line FL and the vehicle approach direction rear target line RL is still smaller than the diagonal dimension of the own vehicle in step S13, It is practical to display “no parking”.

In order to make it more practical, instead of monitoring the distance between the front and rear target lines FL, RL in step S13, the front-rear obstacle between the obstacle ahead of the vehicle in the approach direction and the obstacle behind the approach direction Check whether the distance between objects (parking space length) is larger than the diagonal dimension of the vehicle, and whether the parking space length can park the vehicle.
When it is determined in step S13 that the distance between the front and rear obstacles (actual parking space length) is not larger than the diagonal dimension of the own vehicle (not the parking space length that can park the own vehicle), in step S14, on the monitor 9 A warning “Insufficient parking space length (no parking)” is displayed and the driver is made aware of this.

If it is determined in step S13 that the vehicle can be parked in space, the vehicle is rotated in the target parking space PA in step S15.
When rotating the vehicle, the rotation center is determined as follows unless the vehicle deviates from the target parking space PA during the rotation.

As shown in FIG. 3, when there is enough space behind the direction of entry of the vehicle, the rotation center O1 of the vehicle is positioned near the front of the direction of entry of the vehicle on the side close to the vehicle side target line SL. Determine the steering angle.
The steering angle of each wheel that realizes such a rotation center O1 is such that the rotation axis of each wheel passes through the vehicle rotation center O1, as shown in FIG. 3, and the controller 6 uses this steering angle as the steering angle of each wheel. The command value is transmitted to the steering actuators 3L, 3R, 4L, 4R.
By such steering angle control of each wheel, the vehicle heads toward the parking position while being rotated in the direction indicated by the arrow in FIG. 3 around the front portion in the approach direction of the vehicle on the side close to the vehicle side target line SL. However, at this time, since the rotation center O1 is as described above, it is possible to move the vehicle toward the parking position while moving backward in the approach direction with sufficient space. Parking is possible.

In step S16, while the vehicle is rotating around the center O1, the vehicle position in the target parking space PA is continuously detected, and the vehicle is set at a predetermined parking position parallel to the vehicle side target line SL, for example. Check if it has been reached.
In step S16, when the vehicle reaches a predetermined parking position, it is determined that parking is completed, and the control is terminated.
However, while it is determined in step S16 that parking is not completed, the control is advanced to step S17 and thereafter, and it is continuously checked whether or not the vehicle deviates from the target parking space PA by determining the position of the vehicle in the target parking space PA. If not deviating, the control is returned to step S13 and the above loop is repeatedly executed, so that the host vehicle is continuously rotated around the center O1 to the parking completion position.

By the way, when the host vehicle is rotating around the center O1, as shown in FIG. 4, when the host vehicle tries to deviate from the target parking space PA in the rear target line RL in the vehicle approach direction, step S17 selects step S18. After changing the rotation center of the own vehicle as follows, the control is returned to step S13.
In step S18, in response to the vehicle deviating from the target parking space PA in the vehicle approach direction rearward target line RL as described above (see FIG. 4), the deviating vehicle part about to deviate as shown in FIG. A line β obtained by offsetting a line α parallel to the vehicle side target line SL in a direction away from the vehicle side target line SL so that the vehicle does not exceed the vehicle side target line SL at the time of rotation,
The intersection O2 with the line γ obtained by offsetting the vehicle target direction forward target line FL to the rear of the vehicle approach direction so that the vehicle does not exceed the vehicle target direction front target line FL when the host vehicle is rotating is the new center of rotation of the host vehicle. In other words, the steering angle of each wheel is changed so that the vehicle rotation center moves from the previous O1 in the direction opposite to the moving direction of the deviating vehicle part and is changed to the intersection O2.

The new rotation center O2 thus changed replaces the previous rotation center O1 in the subsequent rotation of the host vehicle in step S15.
The steering angle of each wheel that realizes the rotation center O2 is also a steering angle such that the rotation axis of each wheel passes through the vehicle rotation center O2, as shown in FIG. 4, and the controller 6 uses this steering angle as the steering angle of each wheel. The command value is transmitted to the steering actuators 3L, 3R, 4L, 4R.
As a result of the steering angle control of each wheel, the host vehicle continues to rotate in the same direction around the new center O2 changed as described above and moves toward the final target parking position as shown in FIG.
By the way, since the center of rotation is changed from the current O1 to O2 moved in the direction opposite to the moving direction of the deviating vehicle part, the vehicle part is prevented from deviating from the target parking space PA, while The car can be parked at the final target position shown in FIG.

By the way, conventionally, when it was found that the vehicle departed from the target parking space during the parking operation, there was a trouble that the vehicle trajectory calculation must be performed again from the beginning and the parking must be performed again based on the guidance of the vehicle based on this. But,
According to the present embodiment, as described above, when deviation from the target parking space PA is found, it is possible to avoid the deviation only by changing (moving) O1 → O2 of the vehicle rotation center by changing the steering angle of each wheel. Thus, it is possible to realize the excellent parking support by avoiding the above trouble of having to restart the vehicle trajectory calculation from the beginning and to perform the parking again by the guidance of the vehicle based on this.

  In addition, according to the present embodiment, the above-described excellent parking assistance can be realized only by setting the rotation center of the vehicle by individual steering of each wheel. There is no need to rely on precise vehicle guidance based on the

Contrary to the case of FIG. 3, when there is a space in front of the own vehicle as shown in FIG. 6, in step S15 of FIG. 2, the own vehicle is rotated in the target parking space PA as follows. Let it be done.
When the host vehicle is rotating, unless the host vehicle deviates from the target parking space PA during the rotation, the center of rotation O3 as shown in FIG. 6 is the front part of the host vehicle in the approach direction on the side far from the vehicle side target line SL. The steering angle of each wheel is determined so that the center of rotation O3 exists at this position.

The steering angle of each wheel that realizes the rotation center O3 is a steering angle such that the rotation axis of each wheel passes through the vehicle rotation center O3 as shown in FIG. 6, and the controller 6 determines this steering angle as the steering angle of each wheel. The command value is transmitted to the steering actuators 3L, 3R, 4L, 4R.
By such steering angle control of each wheel, the vehicle heads toward the parking position while being rotated in the direction indicated by the arrow in FIG. 6 around the front portion in the approach direction of the vehicle on the side far from the vehicle side target line SL. However, at this time, the rotation center O3 is as described above, so that the vehicle can be moved to the parking position while moving forward in the approach direction with sufficient space, and the space can be used effectively. Parking is possible.

  In step S16 of FIG. 2, when it is determined that the vehicle has reached a predetermined parking position parallel to the vehicle side target line SL due to rotation around the center O3, the control is terminated as parking completed. While it is determined that parking is not completed in step S16, the control is advanced to step S17 and thereafter, and it is continuously checked whether or not the vehicle deviates from the target parking space PA by determining the position of the vehicle in the target parking space PA. If it does not deviate, control is returned to step S13 and the above loop is repeatedly executed to continuously rotate the host vehicle around the center O3 to the parking completion position.

By the way, if the vehicle is going to deviate from the target parking space PA in the vehicle side target line SL as shown in FIG. 7 while the vehicle is rotating around the center O3, step S17 selects step S18. After changing the center of rotation of the car as follows, control is returned to step S13.
In step S18, in response to the vehicle deviating from the target parking space PA in the vehicle side target line SL as described above (see FIG. 7), the vehicle passes through the deviating vehicle portion that is about to deviate as shown in FIG. A line ε obtained by offsetting a line δ parallel to the vehicle approach direction rear target line RL to the rear of the vehicle approach direction so that the host vehicle does not exceed the vehicle approach direction front target line FL during the rotation,
The intersection point O4 with the line η obtained by offsetting the vehicle side target line SL in a direction away from the vehicle side target line SL so that the vehicle does not exceed the vehicle target direction rear target line RL at the time of the rotation described above is the own vehicle The steering angle of each wheel is adjusted so that it becomes a new center of rotation, that is, the vehicle center of rotation moves from the previous O3 in the direction opposite to the moving direction of the deviating vehicle part and is changed to the intersection point O4. change.

The new rotation center O4 thus changed replaces the previous rotation center O3 in the subsequent rotation of the vehicle in step S15.
The steering angle of each wheel that realizes this rotational center O4 is also a steering angle such that the rotational axis of each wheel passes through the vehicle rotational center O4 as shown in FIG. 7, and the controller 6 determines this steering angle as the steering angle of each wheel. The command value is transmitted to the steering actuators 3L, 3R, 4L, 4R.
By such steering angle control of each wheel, the host vehicle continues to rotate in the same direction around the new center O4 that has been changed as described above, and goes toward the final target parking position as shown in FIG.
By the way, since the center of rotation is changed from O3 so far to O4 moved in the direction opposite to the moving direction of the deviating vehicle part, the vehicle part is prevented from deviating from the target parking space PA, while The car can be parked at the final target position shown in FIG.

  Moreover, as in the past, when it is found that the vehicle deviates from the target parking space, the vehicle trajectory calculation is restarted from the beginning, and the parking of the target is performed without the hassle of performing the parking again by guiding the vehicle based on this. When departure from space PA is found, it is possible to avoid the departure by simply changing (moving) O3 → O4 at the center of rotation of the vehicle by changing the steering angle of each wheel. it can.

9 to 11 show a steering control system for an electric vehicle including a parking assist apparatus according to another embodiment of the present invention, wherein 1L and 1R are left and right front wheels, and 2L and 2R are left and right rear wheels, respectively.
The left and right front wheels 1L and 1R and the left and right rear wheels 2L and 2R are attached to the vehicle body 5 so as to protrude from the corresponding four corners of the vehicle body 5, respectively.
For this reason, the wheels 1L, 1R, 2L, and 2R are not directly attached to the vehicle body 5, but are indirectly attached to the vehicle body 5 via the wheel unit bases 12L, 12R, 13L, and 13R.
Accordingly, the wheels 1L, 1R, 2L, and 2R are attached to the individual wheel unit bases 12L, 12R, 13L, and 13R, and these wheel unit bases 12L, 12R, 13L, and 13R are attached to the vehicle body 5.

When each wheel 1L, 1R, 2L, 2R is attached to each wheel unit base 12L, 12R, 13L, 13R, each wheel 1L, 1R, 2L, 2R is driven by an individual built-in motor (in-wheel motor) In addition, the steering angle can be individually controlled by the individual steering actuators 3L, 3R, 4L, 4R.
When attaching the wheel unit bases 12L, 12R, 13L, 13R to the vehicle body 5, the position of the wheel unit bases 12L, 12R, 13L, 13R is individually controlled with respect to the vehicle body 5 by the base movement actuators 14L, 14R, 15L, 15R. Install as possible.

As shown in FIG. 11, the vehicle body 5 is provided with a controller 6 that issues a steering angle command to the steering actuators 3L, 3R, 4L, 4R and issues a wheel unit base movement command to the base movement actuators 14L, 14R, 15L, 15R.
The wheel unit bases 12L, 12R, 13L, and 13R also have cameras (or distance sensors that measure the distance to obstacles) 7L, 7R, for checking the surrounding conditions of the vehicle when setting the target parking space. Install 8L and 8R.

  Cameras (or distance sensors that measure the distance to the obstacle) 7L and 7R are attached to the wheel unit bases 12L and 12R that protrude from the front left and right corners of the vehicle body 5, and are mounted on the front and side of the vehicle. Check the surrounding conditions and measure the distance to the obstacle in front of the vehicle and on the side of the vehicle. The cameras (or distance sensors that measure the distance to the obstacle) 8L, 8R Mounted on the wheel unit bases 13L and 13R that protrude from the corners, check the surrounding conditions of the rear and side of the vehicle, and measure the distance to the obstacle in the rear and side of the vehicle. Information to be input to the controller 6.

The vehicle body 5 is further equipped with a monitor 9 for allowing the driver to indicate the target parking space on the screen, and a parking assist switch 10 is provided near the steering wheel 10.
The parking assistance switch 11 is turned on when the driver wants to enter the place where the driver wants to park and starts the parking assistance, and is turned off when the parking is finished. A parking assistance start signal is sent to 6, and parking assistance by the controller 6 is started.

The parking assistance control executed by the controller 6 will be described below based on FIGS.
Regarding the setting of the vehicle side target line SL, the vehicle approach direction forward target line FL, and the vehicle approach direction rear target line RL related to the target parking space PA, the driver may perform the setting or automatically. This is basically done in the same manner as described above with reference to FIGS.
In addition, the rotation of the vehicle when the vehicle is parked at a predetermined position in the target parking space PA, and the change of the rotation center when the vehicle deviates from the target parking space PA during this rotation are basically This is done in the same manner as described above for FIGS.

Incidentally, as described above with reference to FIGS. 3 to 5, parking assistance control when there is a space margin behind the vehicle approach direction will be described below with reference to FIGS. 12 to 14.
As shown in FIG. 12, when there is a sufficient space behind the direction of entry of the vehicle, the rotation center O1 of the vehicle is positioned so that the rotation center O1 of the vehicle is located near the front direction of the vehicle on the side close to the vehicle side target line SL. Determine the steering angle.
That is, the steering angle of each wheel is set so that the rotation axis of each wheel is directed toward the vehicle rotation center O1, as shown in FIG. 12, and the controller 6 uses these steering angles as steering angle command values for each wheel. Send to 3L, 3R, 4L, 4R.
By such steering angle control of each wheel, the vehicle heads toward the parking position while being rotated in the direction indicated by the arrow in FIG. 12 around the front near the front direction of the vehicle on the side close to the vehicle side target line SL. .

  During the rotation of the vehicle around the center O1, the vehicle position in the target parking space PA is continuously detected, and parking is performed when the vehicle reaches a predetermined parking position parallel to the vehicle side target line SL, for example. The control is terminated by determining that the vehicle is complete, but until then, the vehicle position in the target parking space PA is checked to see if it deviates from the target parking space PA. For example, the vehicle is continuously rotated around the center O1 to the parking completion position.

By the way, if the vehicle (the left wheel unit at the rear in the approach direction) tries to deviate from the target parking space PA in the vehicle approach direction rear target line RL as shown in FIG. It is possible to avoid the departure from the target parking space PA by changing the rotation center of the vehicle from the above O1 in the same manner as described above with reference to FIG.
However, in the present embodiment, each wheel unit can control the relative position with respect to the vehicle body 5, and the amount of protrusion from the vehicle body 5 can be adjusted, so in conjunction with the change of the rotation center, or separately from this, The deviating wheel unit that is about to deviate from the target parking space PA is moved backward so as to approach the vehicle body 5 and reduce the amount of protrusion in the future by the corresponding actuator.

  By moving the deviating wheel unit in this way, even if the vehicle continues to rotate in the same direction around the same center O1, the wheel unit deviates from the target parking space PA in the vehicle target direction rearward target line RL. The vehicle can finally be directed to the target parking position as shown in FIG.

1 is a schematic system diagram showing a steering control system for a vehicle including a parking assist device according to an embodiment of the present invention. 2 is a flowchart of a parking assistance control program to be executed by a controller in FIG. FIG. 3 is an explanatory diagram of a monitor screen showing a state when there is a space margin behind the entry direction when the own vehicle enters the parking space to start parking support by the control program of FIG. FIG. 4 is an explanatory diagram of a monitor screen showing a state when the rear part of the vehicle approach direction deviates from the vehicle entry direction rear target line of the parking space when the own vehicle is rotated from the approach position of FIG. 3 toward the parking position. FIG. 5 is an explanatory diagram of a monitor screen showing a parking completion state in which the own vehicle has finished rotating from the position of FIG. 4 to a predetermined parking position in the parking space. FIG. 3 is an explanatory diagram of a monitor screen showing a state where there is a space margin ahead in the approach direction when the host vehicle enters the parking space to start parking support by the control program of FIG. FIG. 7 is an explanatory diagram of a monitor screen showing a state where the front part of the vehicle approach direction deviates from the side target line of the parking space when the own vehicle is rotated from the approach position of FIG. 6 toward the parking position. FIG. 8 is an explanatory diagram of a monitor screen showing a parking completion state in which the own vehicle has finished rotating from the position of FIG. 7 to a predetermined parking position in the parking space. It is a top view of the vehicle provided with the parking assistance apparatus which becomes another Example of this invention. FIG. 10 is a side view of the vehicle shown in FIG. FIG. 11 is a schematic system diagram showing the vehicle steering control system and the wheel unit moving system shown in FIGS. FIG. 12 is an explanatory diagram of a monitor screen showing a state when there is a space margin behind the entry direction when the vehicle shown in FIGS. FIG. 13 is an explanatory diagram of a monitor screen showing a state in a case where a rear wheel unit in the vehicle entry direction deviates from a vehicle entry direction rear target line in the parking space when the vehicle is rotated from the entry position in FIG. 12 to the parking position. FIG. 14 is an explanatory diagram of a monitor screen showing a parking completion state in which the vehicle has finished rotating from the position of FIG. 13 to a predetermined parking position in the parking space.

Explanation of symbols

1L, 1R left and right front wheels
2L, 2R left and right rear wheels
3L, 3R Steering actuator for left and right front wheels
4L, 4R Steering actuator for left and right rear wheels 5 Car body 6 Controller
7L, 7R, 8L, 8R camera (or distance sensor)
9 Monitor
10 Steering wheel
11 Parking support switch
12L, 12R, 13L, 13R Wheel unit
14L, 14R, 15L, 15R Wheel unit movement actuator

Claims (13)

In a parking assistance device used for a vehicle capable of individually changing the steering angle of each wheel,
Target parking space setting means for automatically setting the target parking space according to the driver's driving operation or by the driver according to a command;
Deviation determination means for determining whether the vehicle deviates from the target parking space set by the means;
When it is determined that the vehicle departs from the target parking space by the means, the rotation center of the vehicle changes from the rotation center of the vehicle based on the current steering angle of each wheel to a direction opposite to the moving direction of the deviating vehicle part. A vehicle parking assistance device comprising own vehicle rotation center changing means for changing the steering angle of each wheel so as to move. In the vehicle parking assistance device according to claim 1,
The target parking space setting means includes obstacle detection means for detecting an obstacle on the side of the own vehicle, and a monitor for displaying the side obstacle detected by the means together with the own vehicle. A vehicle parking assistance apparatus, wherein the vehicle side target line of the target parking space is set above. In the vehicle parking assistance device according to claim 1,
The target parking space setting means includes distance detection means for detecting a distance to an obstacle on the side of the host vehicle, and the vehicle side of the target parking space is based on the distance to the side obstacle detected by the means. A parking assist device for a vehicle, wherein the vehicle target line is set. In the vehicle parking assistance device according to claim 2,
The target parking space setting means includes obstacle detection means for detecting obstacles in the forward direction and the backward direction of the own vehicle, and the forward obstacle and the backward obstacle detected in the approach direction are detected by the means. A vehicle parking support apparatus, wherein the vehicle parking assistance device is configured to display on the monitor and to set a vehicle approach direction front target line and a vehicle approach direction rear target line of the target parking space on the monitor. In the vehicle parking assistance device according to claim 3,
The target parking space setting means passes a line perpendicular to the vehicle side target line while passing through the front direction and the rearmost direction of the own vehicle, respectively, and the vehicle target direction front target line and the vehicle approach of the target parking space, respectively. A parking assist device for a vehicle, characterized in that it serves as a direction rear target line. In the vehicle parking assistance device according to claim 3,
The target parking space setting means includes distance detection means for detecting the distance to the obstacle in the approach direction forward and the approach direction rear of the host vehicle, and to the obstacle in the approach direction forward and the approach direction backward detected by the means. A vehicle parking assistance apparatus, wherein a vehicle approach direction front target line and a vehicle approach direction rear target line of the target parking space are set based on a distance. In the vehicle parking assistance device according to any one of claims 1 to 6,
Before the departure determination means determines the departure of the vehicle from the target parking space, if there is a space behind the vehicle entry direction, the vehicle entry direction on the side close to the vehicle side target line A parking assist device for a vehicle, characterized in that the steering angle of each wheel is determined so that the center of rotation of the vehicle is positioned near the front. In the parking assistance device for a vehicle according to any one of claims 1 to 7,
Before the departure determination means determines the departure of the vehicle from the target parking space, if there is a space in front of the vehicle entry direction, the vehicle entry direction on the side far from the vehicle side target line A parking assist device for a vehicle, characterized in that the steering angle of each wheel is determined so that the center of rotation of the vehicle is positioned near the front. In the parking assistance device for a vehicle according to any one of claims 1 to 8,
The own vehicle rotation center changing means passes through the deviating vehicle portion about to depart when the departure determining means determines that the own vehicle departs from the target parking space in the vehicle approach direction rear target line of the target parking space. A line obtained by offsetting a line parallel to the vehicle side target line of the target parking space in a direction away from the vehicle side target line so that the vehicle does not cross the vehicle side target line when the host vehicle is rotating, and the target parking space Each of the intersections with a line obtained by offsetting the vehicle target direction forward target line to the rear of the vehicle approach direction so that the vehicle does not exceed the vehicle target direction front target line when the host vehicle is rotating becomes a new center of rotation of the host vehicle. A vehicle parking assist device for changing a steering angle of a wheel. In the vehicle parking assistance device according to any one of claims 1 to 9,
When the departure determining means determines that the own vehicle deviates from the target parking space in the vehicle side target line of the target parking space, the own vehicle rotation center changing means passes through the deviating vehicle portion that is about to depart. A line obtained by offsetting a line parallel to the rear target line in the vehicle approach direction of the parking space to the rear in the vehicle approach direction so that the vehicle does not exceed the front target line in the target direction of the target parking space when the host vehicle rotates, and the target A new rotation of the vehicle is the intersection of the vehicle side target line in the parking space and the line obtained by offsetting the vehicle side target line away from the vehicle side target line so that it does not cross the rear target line when the vehicle rotates. A parking assist device for a vehicle, wherein the steering angle of each wheel is changed so as to be the center. In the vehicle parking assistance device according to any one of claims 1 to 10, wherein the vehicle is capable of individually controlling a relative position of each wheel with respect to the vehicle body.
When the departure determining means determines that the wheel departs from the target parking space, the departure from the target parking space in a direction away from the target line of the target parking space that passes when the wheel deviates. A vehicle parking assistance device, characterized in that wheel moving means for moving to a position where there is no problem is provided. In the parking assistance device for a vehicle according to any one of claims 1 to 11,
When the distance between the vehicle target direction forward target line and the vehicle target direction rear target line of the target parking space is smaller than the diagonal dimension when viewed from above the host vehicle, the vehicle target direction forward target line and the vehicle approach A vehicle parking support apparatus, wherein the vehicle approach direction front target line and the vehicle approach direction rear target line are reset so that a distance between the direction rear target lines becomes larger than the diagonal direction dimension. In the vehicle parking assistance device according to any one of claims 1 to 12,
Parking assistance for a vehicle, characterized in that it is configured to issue a parking impossibility warning when the parking space length between obstacles on both sides in the longitudinal direction of the own vehicle is smaller than the diagonal dimension when viewed from above the own vehicle. apparatus.

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