JP3866223B2 - Vehicle travel support device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle travel support device that obtains a travel locus to a target position and assists vehicle travel so that the vehicle follows the travel locus.
[0002]
[Prior art]
Techniques for performing steering support and automatic steering so that a vehicle follows a predetermined travel locus are known, and automatic travel apparatuses and parking support apparatuses (for example, see Patent Document 1) that employ this technique. It has been known.
[0003]
In the technology of Patent Document 1, when supporting parallel parking or reverse parking, a route (traveling locus) from the current vehicle position to the target parking position is calculated, and the vehicle is guided along the traveling locus. In calculating the travel locus, the locus is calculated by a combination of a straight line and an arc having a radius greater than the minimum turning radius of the vehicle. Thereby, it is possible to easily calculate only a 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 a combination of such an arc and a straight line, the steering amount does not reach the target value, the turning radius becomes large, or the deviation from the target trajectory occurs due to the difference in speed, etc. As it is, the target position cannot be reached even with the minimum turning radius. As a result, it is not possible to reach the target position in a single backward movement, so that a turn-back operation or the like is required, it becomes difficult to reset the trajectory, and operability is not sufficient.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicular travel support apparatus that improves the degree of freedom of resetting the travel trajectory and thus improves operability.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, a vehicle travel support device according to the present invention obtains a target travel locus to a target position and supports the vehicle travel so as to follow the target travel locus. in a minimum be capable of resetting of a target running locus starting from the current position in response to an instruction or the running condition of the driver, the minimum turning radius to be used the first time calculation of target running locus vehicle-specific in driving support If it is set to be larger than the turning radius, it is determined whether or not the target travel locus can be set by the initial calculation, and if it is determined that the target travel locus cannot be set by the initial calculation, the determination result is notified to the driver. Features.
[0008]
In this way, by setting the minimum turning radius used for calculating the travel locus to be larger than the minimum turning radius unique to the vehicle at the time of initial calculation, the target travel locus that is initially set is the limit trajectory using the minimum turning radius. And a trajectory with sufficient control can be set. For this reason, it is necessary to reset the target travel trajectory when the actual travel trajectory deviates from the target trajectory, when the driver moves the target position, or when the driver instructs the resetting itself. In some cases, the resetting is easy and the degree of freedom is increased. For this reason, the case where the target trajectory cannot be reached is reduced if switching is not performed at the time of resetting, and the operability is improved.
[0009]
It is preferable to change the minimum turning radius used when resetting the target travel locus to be smaller than the minimum turning radius used during the initial calculation . Thereby, at the time of resetting, it is possible to take a path with a larger curvature (smaller turning radius) than at the time of the initial calculation , so that the degree of freedom in selecting a target path is increased and the calculation of the path becomes easy.
[0010]
Alternatively, the minimum turning radius used when resetting the target travel locus may be changed to be smaller as the travel distance of the travel locus becomes longer . If it does in this way, a path | route with a large turning curvature (small turning radius) can be taken, so that it approaches a target position, and control becomes easy.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted.
[0012]
Hereinafter, a parking assistance device will be described as an example of the driving assistance device according to the present invention. FIG. 1 is a block configuration diagram of a parking assistance apparatus 100 according to an embodiment of the present invention. The parking assistance device 100 includes a travel control device 110 and an automatic steering device 120, and is controlled by a parking assistance 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, and includes a travel control unit 10 that controls the travel control device 110 and a steering control unit 11 that controls the automatic steering device. And have. The travel control unit 10 and the steering control unit 11 may be separated in hardware in the parking assist ECU 1, but may be separated in software using a common CPU, ROM, RAM, and the like.
[0013]
The travel control device 110 includes the travel control unit 10 described above, a braking system, and a drive system. The braking system is an electronically controlled brake (ECB) system in which the braking force applied to each wheel is electronically controlled by the brake ECU 31, and the brake hydraulic pressure applied to the wheel cylinder 38 of the hydraulic brake disposed on each wheel by the actuator 34. Adjust the braking force by adjusting. The brake ECU 31 is disposed in a wheel speed sensor 32 that is disposed on each wheel to detect the wheel speed, an acceleration sensor 33 that detects vehicle acceleration, and an actuator 34, and is added to the inside and the wheel cylinder 38. Each output signal of a master cylinder (M / C) hydraulic sensor 36 that detects the hydraulic pressure of a master cylinder 35 that is connected between the brake pedal 37 and the actuator 34 is not shown. Have 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 communicate with each other and perform cooperative control with the travel control unit 10. 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 that also serves as a power steering device disposed between the steering wheel 40 and the steering gear 41, and a displacement sensor 43 that detects a displacement amount of the steering, and the steering control unit 11 is driven. While controlling the drive of the motor 42, the output signal of the displacement sensor 43 is input.
[0016]
The parking support ECU 1 including the travel control unit 10 and the steering control unit 20 includes an input unit 16 that receives an image signal acquired by the rear camera 15 for acquiring an image behind the vehicle and a driver's operation input for parking support. Are connected to a monitor 13 that displays information by an image to a driver and a speaker 14 that presents information by voice.
[0017]
Next, the assistance operation in this parking assistance device will be specifically described. In the following, as shown in FIG. 2, a description will be given of a support operation when performing so-called garage storage in which a vehicle 200 is accommodated by retreating in a garage 220 provided facing a road 210. FIG. 3 is a control flowchart of this support operation, and FIG. 4 is a graph for explaining a set travel locus (route) in this control.
[0018]
The control shown in FIG. 3 is performed until the driver reaches the vicinity of the instructed target parking position after the driver operates the input means 16 to instruct the parking assist ECU 1 to start the parking assist control. Until it is determined that the vehicle cannot be reached by one backward movement, the parking assistance ECU 1 continues to execute unless the driver cancels the assistance operation from the input means 16.
[0019]
Specifically, the driver moves the vehicle to the parking assistance start position, that is, the position where the target position is reflected in the image captured by the rear camera 15 displayed on the monitor 13, and then the input means 16. To start this 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 point A as shown in FIG. The driver moves the parking frame displayed on the screen to the target parking position by operating the input unit 16 while viewing the image captured by the rear camera 15 displayed on the monitor 13. By doing so, the target parking position G is set (step S2).
[0020]
The parking assist ECU 1 obtains the position of the point G by image recognition processing. What is necessary is just to obtain | require the position of this G point as a relative coordinate which makes the present vehicle position A the origin, for example. 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 larger than the actual minimum turning radius Rmin.
[0021]
Then, using this minimum turning radius Rcal, a route (traveling locus) 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 travel distance. Here, the turning curvature is the reciprocal of the turning radius. In the following description, the case of turning to the left is represented by plus, and the case of turning to the right is represented by minus. Thus, by setting the target travel locus as the correspondence between the travel distance and the steering angle, the travel distance can be obtained from the output of the wheel speed sensor 32, and the steering angle is obtained from the output of the displacement sensor 43 which is a steering angle sensor. Since it can be obtained, its detection is easy. Further, since the target travel locus does not depend on the speed and acceleration of the vehicle, there is an advantage that the control can be simplified.
[0022]
As shown by the thick lines in FIGS. 4 (a) and 4 (b), the target route obtained at this time is steered to a predetermined turning curvature, held constant, and then returned to steering in the neutral position. The target position is reached.
[0023]
In step S8, it is determined whether a route has been set. Even if the maximum turning curvature is maintained, the target position G cannot be reached from the current position A, and if 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. The driver is notified 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]
When the target route can be set, the process proceeds to step S12, and the process proceeds to actual support control. Here, it is preferable that the travel control unit 10 of the parking assist ECU 1 instructs the engine ECU 21 to torque up the engine 22 when the shift lever is set to the reverse position. As a result, the engine 22 rotates at a higher rotational speed than during normal idling, and shifts to a torque-up state with a high driving force. For this reason, 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 operated in accordance with the pedal opening to adjust the wheel cylinder hydraulic pressure (brake hydraulic pressure) applied to the wheel cylinder 38, and the braking force applied to each wheel. Adjust. This adjusts the vehicle speed. At this time, the upper limit vehicle speed is guarded by applying a braking force by adjusting the brake hydraulic 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.
[0025]
While monitoring the output of the displacement sensor 43, the steering control unit 11 controls the drive motor 42 and operates the steering gear 41 to control the steering angle so as to match the steering angle displacement obtained by the parking assist ECU 1. Since the movement along the route set in this way is performed, the driver can concentrate on safety confirmation on the route and vehicle speed adjustment. If there are obstacles, pedestrians, etc. on the path, when the driver depresses the brake pedal 37, the braking force corresponding thereto is applied to the wheel cylinder 38 via the actuator 34 under the control of the brake ECU 31, which is safe. You can slow down and stop.
[0026]
Next, the current position is determined (step S14). The current position can be determined based on the movement of the feature point in the image captured by the rear camera 15, or 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 or not the current position is deviated from the target route. If the deviation is large, it is determined that the route needs to be reset (step S16). When it is necessary to reset the route, the process proceeds to step S22, and the minimum turning radius Rcal is replaced with the minimum turning radius Rmin. And it returns to step S6 and resets a path | route.
[0028]
On the other hand, when the deviation from the target route is small, the process proceeds to step S18 to determine whether or not the vicinity of the target parking position G point has been reached. If the target parking position has not been reached, the support control is continued by returning to step S12. If it is determined that the vehicle has reached the target parking position, the process proceeds to step S20, the driver is notified that the vehicle has reached the target parking position by the monitor 13 and the speaker 14, and the process is terminated.
[0029]
In this embodiment, the minimum turning radius used at the time of setting the first route is set larger than the actual minimum turning radius specific to the vehicle (the maximum turning curvature used at the time of setting the route is smaller than the actual maximum turning curvature specific to the vehicle). Set).
[0030]
Here, the case where the route setting is always performed using the minimum turning curvature inherent to the vehicle as in the prior art and the route setting of the present embodiment will be compared and described. In the conventional route setting, first, as shown by a solid line in FIG. 2, a route Lt1 (traveling locus shown by a thick line in FIG. 4A) using the minimum turning radius Rmin possible for the vehicle is set and control is performed. If so, the route La1 was actually moved due to some reason (for example, insufficient output of the drive motor 42, the driver was applying a reaction force to the steering wheel 40, the vehicle speed was too fast, etc.) In such a case (the trajectory indicated by a thick line in FIG. 4A), even if an attempt is made to reset the route at point B where the deviation from the route becomes so large that resetting is required, the minimum possible vehicle from there Even if the vehicle travels on a route that takes the turning radius Rmin (maximum turning curvature) (route Lt1 ′ in FIG. 2), the vehicle cannot move to the point G, which is the target parking position, and the vehicle can reach the point G. Turning radius R smaller than minimum turning radius Rmin _{1 Since} it is necessary to move along a path (path Lt1 ″ in FIG. 2, a locus indicated by a broken line in FIG. 4A) that takes (the turning curvature exceeding the maximum turning curvature), it is actually determined that the movement is impossible. Then, in order to move to the point G, which is the target parking position, it is necessary to perform turning back to advance once.
[0031]
On the other hand, according to the present invention, when the route is set for the first time, 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. (Trajectory indicated by bold line) is set. For this reason, the locus cannot be traced for some reason (see the route La2 in FIG. 2 and the locus of the broken line in FIG. 4A), a deviation occurs, and the deviation from the route is large enough to require resetting. When there is an attempt to reset the route at the point C, the available curvature (turning radius) has a margin, so a larger steering angle (route Lt2 ′ in FIG. 2) is used to reach the target position. Is possible.
[0032]
In this way, since a route with a margin that can be further turned at the time of resetting can be set, 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 the difference between the current position and the target route is determined as a condition for resetting the target route, and the reset is performed when it is determined that the difference is large. However, the resetting condition is not limited to this. For example, the driver may further include means for instructing route resetting, and the route resetting may be performed in accordance with the instruction. This resetting instruction can be given by the input means 16, for example. Alternatively, even when the driver moves the target position with the input means 16 during driving support, the current position cannot be reached on the current route, and route setting is necessary. This case can also be included in the reset condition.
[0034]
Here, an example has been described in which the route is set using the minimum turning radius unique to the vehicle at the time of resetting, but the present invention is not limited to this. For example, when the number of resets exceeds a predetermined number or step by step, the minimum turning radius used for calculation may be reduced (maximum turning curvature is increased), and the longer the travel distance is ( 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 resetting the route according to the driver's instruction, the minimum turning radius can be reduced every time the driver instructs resetting. If the target position is reset, the minimum turning radius may be reduced each time the setting is reset, or the distance to the previous target position and the distance to the target position after setting are compared. Thus, the minimum turning radius at the time of resetting may be obtained. In this way, the degree of freedom for resetting the route is improved.
[0035]
In the above description, the embodiment of the parking assist device having the automatic steering function has been described. However, not only the technology for performing the steering automatically, but also the parking for performing the steering guidance for instructing the appropriate steering amount to the driver. The support device can be used similarly. Further, the present invention is not limited to a parking assistance device, and can be applied to a traveling assistance 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 route to be moved is set using a turning radius larger than the minimum turning radius unique to the vehicle, and a smaller turning radius is set in the subsequent resetting. By making it possible to set the route that moves, it is easy to reset even if there is a deviation from the first set route, and the degree of freedom in setting the route increases, so the vehicle is surely guided to the target position. be able to. For this reason, operability is improved.
[Brief description of the drawings]
FIG. 1 is a block configuration diagram of a parking assistance device as an embodiment of a driving assistance device according to the present invention.
FIG. 2 is a diagram for explaining a travel locus when a garage assist operation is performed by the apparatus of FIG. 1;
FIG. 3 is a flowchart of the support operation of FIG. 2;
4 is a graph for explaining a set travel locus (route) in the control of FIG. 3;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Parking assistance ECU, 10 ... Driving control part, 11 ... Steering control part, 12 ... Shift sensor, 13 ... Monitor, 14 ... Speaker, 15 ... Rear camera, 16 ... Input means, 21 ... Engine ECU, 22 ... Engine, DESCRIPTION OF SYMBOLS 31 ... Brake ECU, 32 ... Wheel speed sensor, 33 ... Acceleration sensor, 34 ... Actuator, 35 ... Master cylinder, 36 ... Hydraulic sensor, 37 ... Brake pedal, 38 ... Wheel cylinder, 40 ... Steering wheel, 41 ... Steering gear, DESCRIPTION OF SYMBOLS 42 ... Drive motor, 43 ... Displacement sensor, 5 ... Vehicle, 61, 62 ... Other vehicle, 100 ... Parking assistance apparatus, 110 ... Traveling control apparatus, 120 ... Automatic steering apparatus.

Claims (3)

In a vehicle travel support device for obtaining a target travel locus to a target position and assisting the vehicle to follow the target travel locus,
It is possible to reset the target travel locus starting from the current position according to the driver's instruction or the travel state during the travel support, and the minimum turning radius used for the initial calculation of the target travel locus is the minimum turn specific to the vehicle. Setting larger than the radius , determining whether the target travel locus can be set by the initial calculation, and notifying the driver of the result of the determination when it is determined that the target travel locus cannot be set by the initial calculation. A vehicle travel support apparatus characterized by the above. The vehicle travel support apparatus according to claim 1 , wherein the minimum turning radius used when resetting the target traveling locus is changed to be smaller than the minimum turning radius used during initial calculation . The vehicle travel support apparatus according to claim 1 , wherein the minimum turning radius used when resetting the target travel locus is changed as the travel distance of the travel locus becomes longer .

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