JP2004352110A - Travel supporting device for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a travel supporting device for vehicles improved in a degree of freedom in re-setting of a travelling locus and also improved in operation performance. <P>SOLUTION: In the travel supporting device for vehicles such as a parking supporting device to support a vehicle 200 in travelling to follow a travelling locus Lt2 based on that to a target position G, the turning radius used for calculating the travelling radius is restricted to set a route using a large turning radius at an initial stage, thereby improving flexibility in re-setting of a route so as to correspond to a possible deviation from the set route. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicular travel support device that obtains a travel locus to a target position and assists the vehicle in traveling such that the vehicle follows the travel locus.
[0002]
[Prior art]
2. Description of the Related Art Techniques for performing steering assistance and automatic steering so that a vehicle travels following a predetermined traveling locus are known, and automatic traveling apparatuses and parking assistance apparatuses (for example, see Patent Literature 1) adopting this technique. It has been known.
[0003]
In the technique of Patent Literature 1, a path (traveling locus) from a current vehicle position to a target parking position is calculated when assisting parallel parking or reverse parking, and a vehicle is guided along the traveling locus. In calculating the traveling locus, the locus is calculated by a combination of a straight line and an arc having a radius equal to or larger than the minimum turning radius of the vehicle. As a result, it is possible to easily calculate only the feasible trajectory.
[0004]
[Patent Document 1]
JP 2000-72019 (Paragraph 0024, FIG. 3)
[0005]
[Problems to be solved by the invention]
However, when the trajectory is calculated by such a combination of an arc and a straight line, when the steering amount does not reach the target value and the turning radius increases, or when a deviation from the target trajectory occurs due to a difference in speed, As it is, it is impossible to reach the target position even with the minimum turning radius. As a result, a single retreat cannot reach the target position, necessitating a switching operation or the like, making it difficult to reset the trajectory, and resulting in insufficient operability.
[0006]
Accordingly, it is an object of the present invention to provide a vehicle travel support device that improves the degree of freedom in resetting a travel locus and thereby improves operability.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a vehicular travel support device according to the present invention obtains a target travel locus to a target position and assists the vehicle to travel so as to follow the target travel locus. In the driving support, it is possible to reset the target traveling trajectory starting from the current position according to the driver's instruction or traveling state, and the minimum turning radius used for the first time calculation of the target traveling trajectory is the vehicle-specific minimum radius. The turning radius is set to be larger than the turning radius.
[0008]
By setting the minimum turning radius used for calculating the traveling locus larger than the minimum turning radius specific to the vehicle at the time of the first calculation in this way, the target traveling locus initially set is the ultimate locus using the minimum turning radius. Therefore, it is possible to set a trajectory with sufficient control. For this reason, it is necessary to reset the target traveling locus such as when the actual traveling locus deviates from the target locus, when the driver moves the target position, or when the driver instructs the re-establishment. In that case, the resetting is facilitated, and the degree of freedom is increased. For this reason, the case where it is not possible to reach the target trajectory without switching back when resetting is reduced, and the operability is also improved.
[0009]
It is preferable to change the minimum turning radius used at the time of recalculating the target traveling locus to be small. Thereby, at the time of recalculation, a path having a larger curvature (small turning radius) can be taken, so that the degree of freedom in selecting the target trajectory is increased, and the trajectory is easily calculated.
[0010]
Alternatively, the minimum turning radius used at the time of recalculating the target traveling locus may be changed to a small value according to the moving distance of the traveling locus. In this manner, a path having a larger turning curvature (small turning radius) can be taken as the position approaches the target position, and control becomes easier.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate understanding of the description, the same components are denoted by the same reference numerals as much as possible in each drawing, and redundant description is omitted.
[0012]
Hereinafter, a parking assist device will be described as an example of the driving assist device according to the present invention. FIG. 1 is a block configuration diagram of a parking assistance device 100 according to an embodiment of the present invention. The parking assist device 100 includes a travel control device 110 and an automatic steering device 120, and is controlled by a parking assist ECU 1 that is a control device. The parking assist ECU 1 includes a CPU, a ROM, a RAM, an input signal circuit, an output signal circuit, a power supply circuit, and the like. The traveling control unit 10 controls the traveling control device 110 and the steering control unit 11 controls the automatic steering device. And The traveling control unit 10 and the steering control unit 11 may be divided in hardware in the parking assist ECU 1, but may be divided in software using a common CPU, ROM, RAM and the like.
[0013]
The traveling control device 110 includes the traveling control unit 10 described above, a braking system, and a driving system. The braking system is an electronic control brake (ECB) system in which a braking force applied to each wheel is electronically controlled by a brake ECU 31. The braking system applies a brake hydraulic pressure applied to a wheel cylinder 38 of a hydraulic brake disposed on each wheel by an actuator 34. The braking force is adjusted by adjusting. The brake ECU 31 is disposed in each wheel and detects a wheel speed, a wheel speed sensor 32 for detecting the vehicle speed, an acceleration sensor 33 for detecting the acceleration of the vehicle, and disposed in an actuator 34. The output signals of a master cylinder (M / C) oil pressure sensor 36 for detecting the oil pressure of a master cylinder 35 connected between the brake pedal 37 and the actuator 34 are shown in FIG. Has been entered.
[0014]
The engine 22 constituting the drive system is controlled by the engine ECU 21, and the engine ECU 21 and the brake ECU 31 mutually communicate information with the travel control unit 10 to perform cooperative control. Here, the output of the shift sensor 12 that detects the shift state of the transmission is input to the engine ECU 21.
[0015]
The automatic steering device 120 includes a drive motor 42 also serving as a power steering device disposed between the steering wheel 40 and the steering gear 41, and a displacement sensor 43 for detecting a displacement of the steering. The output signal of the displacement sensor 43 is input while controlling the driving of the motor 42.
[0016]
The parking assist ECU 1 including the traveling control unit 10 and the steering control unit 20 includes an image signal acquired by a rear camera 15 for acquiring an image behind the vehicle, and an input unit 16 for receiving an operation input of a driver for parking assistance. Is output, and a monitor 13 for displaying information to the driver by image and a speaker 14 for presenting information by voice are connected.
[0017]
Next, a support operation in the parking support device will be specifically described. In the following, as shown in FIG. 2, a description will be given of a support operation in a case where the vehicle 200 is accommodated by retreating in a garage 220 provided facing the road 210, that is, in a garage. FIG. 3 is a control flowchart of this support operation, and FIG. 4 is a graph for explaining a set traveling locus (path) in this control.
[0018]
The control shown in FIG. 3 is performed after the driver operates the input means 16 to instruct the parking assist ECU 1 to start the parking assist control until the vehicle reaches the vicinity of the instructed target parking position or the target parking position. Until it is determined that the vehicle cannot be reached by one retreat, the parking assist ECU 1 continues to execute the process unless the driver cancels the assisting operation from the input unit 16.
[0019]
Specifically, the driver moves the vehicle to the parking assist start position, that is, a position where the target position is reflected in the image captured by the rear camera 15 displayed on the monitor 13, and then inputs the input means 16. To start the parking assist control (start of the control process shown in FIG. 3). The center of gravity of the vehicle 200 at this time is represented by a point A as shown in FIG. The driver operates the input unit 16 while watching the image captured by the rear camera 15 displayed on the monitor 13 to move the parking frame displayed on the screen to the target parking position. Then, the target parking position G is set (step S2).
[0020]
The parking assist ECU 1 obtains the position of the point G by the image recognition processing. The position of the point G may be obtained, for example, as relative coordinates with the current vehicle position A as the origin. Next, the parking assist ECU 1 sets a minimum turning radius Rcal to be used in the next route calculation (step S4). This Rcal is obtained by multiplying the actual minimum turning radius Rmin of the vehicle 200 by a coefficient 1 + α (where α is a positive constant). That is, the minimum turning radius Rcal used in the route calculation is set to be larger than the actual minimum turning radius Rmin.
[0021]
Then, using this minimum turning radius Rcal, a route (travel locus) leading to the target parking position G is calculated (step S6). Here, the trajectory is set as a steering angle (turning curvature) with respect to the traveling distance. Here, the turning curvature is the reciprocal of the turning radius. In the following description, the case of turning left is represented by plus, and the case of turning right is represented by minus. In this way, by setting the target travel locus as the correspondence between travel distance and steering angle, the travel distance can be obtained from the output of the wheel speed sensor 32, and the steering angle can be obtained from the output of the displacement sensor 43 that is a steering angle sensor. Since it can be obtained, its detection is easy. Further, since the target traveling locus does not depend on the speed and acceleration of the vehicle, there is an advantage that control can be simplified.
[0022]
At this time, as shown by the thick line in FIGS. 4 (a) and 4 (b), the target route obtained after steering to a predetermined turning curvature, after maintaining the curvature constant, returning the steering to the neutral position, It reaches the target position.
[0023]
In step S8, it is determined whether a route has been set. If the target position G cannot be reached from the current position A even if the maximum turning curvature is maintained, and it is determined that the route cannot be set, the process proceeds to step S10, and the target position G cannot be reached from the current position A. This is reported to the driver using the monitor 13 and the speaker 14, and the process is terminated. If necessary, the driver may move the vehicle 200 and activate the parking assist operation again.
[0024]
If the target route has been set, the process moves to step S12, and moves to actual support control. Here, it is preferable that the traveling control unit 10 of the parking assist ECU 1 instruct the engine ECU 21 to increase the torque of the engine 22 when the shift lever is set to the reverse position. As a result, the engine 22 rotates at a higher rotation speed than during normal idling, and shifts to a torque-up state in which the driving force is high. Therefore, the vehicle speed range that can be adjusted only by the brake pedal 37 without performing the accelerator operation is expanded, and the controllability of the vehicle is improved. When the driver operates the brake pedal 37, the actuator 34 is actuated in accordance with the pedal opening to adjust the wheel cylinder oil pressure (brake oil pressure) applied to the wheel cylinder 38, and the braking force applied to each wheel To adjust. This adjusts the vehicle speed. At this time, the braking force is applied by adjusting the brake oil pressure applied to each wheel cylinder 38 by the actuator 34 so that the vehicle speed detected by the wheel speed sensor 32 does not exceed the upper limit vehicle speed, and the upper limit vehicle speed is guarded.
[0025]
While monitoring the output of the displacement sensor 43, the steering control unit 11 controls the drive motor 42 to operate the steering gear 41 to control the steering angle to match the steering angle displacement obtained by the parking assist ECU 1. Since the vehicle travels along the route set in this way, the driver can concentrate on the safety check on the course and the vehicle speed adjustment. When an obstacle or a pedestrian is present on the course, when the driver depresses the brake pedal 37, a braking force corresponding thereto is applied to the wheel cylinder 38 via the actuator 34 under the control of the brake ECU 31. Can decelerate and stop.
[0026]
Next, the current position is determined (step S14). This current position determination can be made based on the movement of a feature point in an image captured by the rear camera 15, and can be determined based on the travel distance change based on the output of the wheel speed sensor 32 or the acceleration sensor 33. The determination may be made based on a change in the steering angle based on the output of the displacement sensor 43.
[0027]
Then, it is determined whether the current position is shifted from the target route. If the current position is significantly shifted, it is determined that the route needs to be reset (step S16). If the route needs to be reset, the process proceeds to step S22, where the minimum turning radius Rcal is replaced with the minimum turning radius Rmin. Then, the process returns to step S6 to reset the route.
[0028]
On the other hand, if the deviation from the target route is small, the process proceeds to step S18, and it is determined whether the vehicle has reached the vicinity of the target parking position G point. If the vehicle has not reached the target parking position, the process returns to step S12 to continue the support control. If it is determined that the vehicle has reached the target parking position, the process proceeds to step S20, where the monitor 13 and the speaker 14 notify the driver that the vehicle has reached the target parking position, and the process ends.
[0029]
As described above, in the present embodiment, the minimum turning radius used at the time of setting the first route is set to be larger than the minimum turning radius specific to the actual vehicle (the maximum turning curvature used at the time of setting the route is smaller than the maximum turning curvature specific to the actual vehicle). Setting).
[0030]
Here, a case where the route setting is always performed using the minimum turning curvature unique to the vehicle as in the related art and a route setting according to the present embodiment will be described in comparison. In the conventional route setting, first, as shown by a solid line in FIG. 2, a route Lt1 (a travel locus indicated by a thick line in FIG. 4A) using a minimum turning radius Rmin possible for the vehicle is set, and control is performed. If so, for some reason (for example, the output of the drive motor 42 is insufficient, the driver is applying a reaction force to the steering wheel 40, or the vehicle speed is too high, etc.), the route La1 is actually moved. In such a case (the locus indicated by the bold line in FIG. 4A), even if an attempt is made to reset the route at point B where the deviation from the route is large enough to require resetting, the minimum possible vehicle distance from that point Even if the vehicle moves along a path (path Lt1 ′ in FIG. 2) that takes a turning radius Rmin (maximum turning curvature), the vehicle cannot move to point G, which is the target parking position. Smaller than the minimum turning radius Rmin It is necessary to move along a path (path Lt1 ″ in FIG. 2 and a trajectory indicated by a broken line in FIG. 4A) that takes a large turning radius R ₁ (turning curvature exceeding the maximum turning curvature). It is determined that it is impossible, and in order to move to the point G which is the target parking position, it is necessary to perform the turning back once forward.
[0031]
On the other hand, according to the present invention, at the time of the initial route setting, the route Lt2 (FIG. 4B) using the turning radius R2 (curvature smaller than the maximum turning curvature) larger than the minimum turning radius Rmin possible for the vehicle. (A locus indicated by a thick line). For this reason, it is impossible to follow this path for some reason (see the path La2 in FIG. 2 and the path indicated by the broken line in FIG. 4A), and a deviation occurs, and the deviation from the path is large enough to require resetting. When the route is to be reset at point C, the available curvature (turning radius) has a margin. Therefore, the steering angle is further increased (the route Lt2 ′ in FIG. 2) to reach the target position. Is possible.
[0032]
As described above, since a route that can be further turned can be set at the time of resetting, the degree of freedom of resetting is increased, and the operability of parking assistance is also improved.
[0033]
In the embodiment described above, an example has been described in which a deviation between the current position and the target route is determined as a condition for resetting the target route, and the resetting is performed when it is determined that the deviation is large. However, the condition for resetting is not limited to this. For example, the driver may further include means for instructing a route reset, and the route may be reset according to the instruction. This resetting instruction can be performed by, for example, the input unit 16. Alternatively, even when the driver moves the target position by the input unit 16 during the driving support, the current route cannot reach the target position, so that the route setting is required. This case can also be included in the reset condition.
[0034]
Here, an example in which the route is set using the minimum turning radius unique to the vehicle at the time of resetting has been described, but the present invention is not limited to this. For example, if the number of resets exceeds a predetermined number, or every time the reset is performed, the minimum turning radius used in the calculation may be reduced (the maximum turning curvature is increased), or as the traveling distance increases ( Alternatively, the minimum turning radius may be reduced (the maximum turning curvature is increased) as the distance from the target parking position becomes shorter. When the route is reset according to the driver's instruction, the minimum turning radius can be reduced every time the driver instructs the reset. When the target position is reset, the minimum turning radius may be reduced each time the setting is reset, or a comparison between the distance to the previous target position and the distance to the target position after the setting may be made. May be used to determine the minimum turning radius at the time of resetting. By doing so, the degree of freedom in resetting the route is improved.
[0035]
In the above description, the embodiment in the parking assist device having the automatic steering function has been described. However, not only the technology for automatically steering, but also the parking guidance for providing a steering guidance for instructing an appropriate steering amount to a driver. The support device can be used similarly. Further, the present invention is not limited to the parking assist device, and can be applied to a travel assist device that guides movement according to a route, a lane keeping system, and the like.
[0036]
【The invention's effect】
As described above, according to the present invention, in the initial stage, a path to be moved is set using a turning radius larger than the minimum turning radius specific to the vehicle, and in the subsequent resetting, a small turning radius is set. It is possible to set the route to move, so that even if there is a deviation from the first set route, it is easy to reset and the freedom of setting the route increases, so that the vehicle is reliably guided to the target position be able to. Therefore, the operability is improved.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram of a parking assistance device that is an embodiment of a traveling assistance device according to the present invention.
FIG. 2 is a diagram for explaining a traveling locus when performing a garage assisting operation by the device of FIG. 1;
FIG. 3 is a flowchart of the support operation in FIG. 2;
FIG. 4 is a graph illustrating a set traveling locus (path) in the control of FIG. 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Parking assistance ECU, 10 ... Running control part, 11 ... Steering control part, 12 ... Shift sensor, 13 ... Monitor, 14 ... Speaker, 15 ... Rear camera, 16 ... Input means, 21 ... Engine ECU, 22 ... Engine 31: brake ECU, 32: wheel speed sensor, 33: acceleration sensor, 34: actuator, 35: master cylinder, 36: oil pressure sensor, 37: brake pedal, 38: wheel cylinder, 40: steering wheel, 41: steering gear, 42: Drive motor, 43: Displacement sensor, 5: Vehicle, 61, 62: Other vehicle, 100: Parking assist device, 110: Travel control device, 120: Automatic steering device.

Claims (3)

In a vehicle travel support device that determines a target travel locus to a target position and assists the vehicle in traveling so as to follow the target travel locus,
It is possible to reset a target traveling locus starting from the current position according to a driver's instruction or traveling state during traveling assistance, and the minimum turning radius used for the first calculation of the target traveling locus is a vehicle-specific minimum turning radius. A driving support device for a vehicle, wherein the driving support device is set to be larger than the radius. 2. The driving support device for a vehicle according to claim 1, wherein the minimum turning radius used when resetting the target traveling locus is changed to a small value. The travel support device for a vehicle according to claim 1, wherein the minimum turning radius used when resetting the target travel locus is changed to be small according to the travel distance of the travel locus.

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