JP3828654B2 - Automatic vehicle steering system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic vehicle steering apparatus for automatically parking a vehicle without depending on a driver's steering operation.
[0002]
[Prior art]
Such an automatic steering device for a vehicle is already known, for example, from Japanese Patent Laid-Open No. 4-55168. This automatic vehicle steering device uses an actuator of a conventionally known electric power steering device, and controls the actuator based on the relationship between the moving distance of the vehicle and the turning angle stored in advance, thereby enabling back parking and tandem Parking is done automatically.
[0003]
[Problems to be solved by the invention]
By the way, the conventional automatic steering device for a vehicle detects the moving distance of the vehicle from the number of pulse signals output as the wheels rotate. The pulse signals are the same regardless of the rotation direction of the wheels. Therefore, it is impossible to detect the moving direction of the vehicle. Therefore, if the currently established shift range is the “D” range, it is estimated that the vehicle is traveling forward, and if the currently established shift range is in the “R” range, the vehicle travels backward. It can be estimated that
[0004]
However, even if the shift range is in the “N” range or the “P” range, the vehicle may move due to the inclination or inertia of the road surface. In such a case, the moving direction of the vehicle cannot be estimated. If the automatic steering device is continued as it is, the vehicle may move in an unexpected direction.
[0005]
The present invention has been made in view of the above circumstances, and it is an object of the present invention to reliably prevent a vehicle from moving in an unexpected direction by an automatic steering device when the moving direction of the vehicle becomes indistinguishable. To do.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 includes an actuator for turning a wheel, a shift range detecting means for detecting a shift range of an automatic transmission mounted on a vehicle, and a moving distance of the vehicle. , A movement trajectory setting means for storing or calculating a movement trajectory of the vehicle up to the target position as a relationship of a wheel turning angle with respect to a movement distance including the movement direction of the vehicle, and a movement trajectory setting means In the automatic steering apparatus for a vehicle, the shift range detecting means includes: an actuator control means for controlling the driving of the actuator based on the movement trajectory stored or calculated by the movement distance and the movement distance of the vehicle detected by the movement distance detection means. When the travel distance detecting means detects the travel distance of the vehicle when the travel range is not detected, the actuator Control means is characterized in that it stops the drive of the actuator based on the movement trajectory and the distance traveled.
[0007]
According to the above configuration, if the vehicle moves when the shift range detection means does not detect the travel range, it cannot be determined whether the moving direction is forward or reverse, and therefore, the movement trajectory setting means sets the vehicle. However, in such a case, the actuator control means stops driving the actuator, and the vehicle is prevented from moving in an unexpected direction. It can be avoided.
[0008]
The travel range is a range in which the vehicle travels forward or backward, and corresponds to the “D” range and “R” range of the embodiment. The time when the travel range is not detected is not limited to the case where the shift range is in the stop range (that is, the “N” range or the “P” range). This includes cases where it becomes impossible.
[0009]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, when the shift range detecting means does not detect a travel range, the moving distance detecting means determines the moving distance of the vehicle greater than or equal to a predetermined value. If detected, the actuator control means stops driving the actuator.
[0010]
According to the above configuration, if the moving distance of the vehicle when the shift range detection unit does not detect the travel range is less than the predetermined value, the actuator control unit does not stop driving the actuator, so that the deviation of the target position is large. Convenience can be improved by avoiding that the automatic steering control is interrupted one by one by a slight movement of the vehicle that does not affect the vehicle.
[0011]
The predetermined value is a value at which the deviation of the target position becomes unacceptable when the moving distance of the vehicle exceeds that value, and is set to 20 cm in the embodiment, but can be changed as appropriate.
[0012]
According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, when the shift range detecting means changes from a state in which a travel range is detected to a state in which a travel range is not detected. When the moving distance detecting means continuously detects the moving distance of the vehicle, the actuator control means assumes that the detected travel range is continuously established and drives the actuator. It is characterized by controlling.
[0013]
According to the above configuration, when it is possible to determine the moving direction of the vehicle even if the shift range is not in the traveling range, the automatic steering control is unnecessary by continuing the driving of the actuator by the actuator control means. The convenience can be improved by avoiding the cancellation.
[0014]
According to a fourth aspect of the present invention, in addition to the configuration of any one of the first to third aspects, when the shift range detecting unit does not detect a travel range, the moving distance detecting unit moves the vehicle. When the actuator is detected, the actuator control means ignores the detected moving distance of the vehicle, and controls the driving of the actuator by assuming that the vehicle is not moving.
[0015]
According to the above configuration, when the moving direction of the vehicle cannot be determined, the control is performed by assuming that the vehicle is stopped, thereby reliably stopping the driving of the actuator. Can be prevented from moving in an unexpected direction.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings.
[0017]
1 to 5 show an embodiment of the present invention. FIG. 1 is an overall configuration diagram of a vehicle equipped with an automatic steering device, FIG. 2 is an explanatory diagram of the operation of a back parking / left mode, and FIG. The figure which shows a switch and an automatic parking start switch, FIG. 4 is a flowchart explaining an effect | action, FIG. 5 is explanatory drawing of an effect | action.
[0018]
As shown in FIG. 1, the vehicle V includes a pair of front wheels Wf, Wf and a pair of rear wheels Wr, Wr. A steering wheel 1 and front wheels Wf and Wf which are steering wheels are rotated integrally with the steering wheel 1, a pinion 3 provided at the lower end of the steering shaft 2, a rack 4 meshing with the pinion 3, and a rack 4 Are connected by left and right tie rods 5, 5 provided at both ends, and left and right knuckles 6, 6 connected to tie rods 5, 5. A steering actuator 7 made of an electric motor is connected to the steering shaft 2 via a worm gear mechanism 8 in order to assist the operation of the steering wheel 1 by the driver or to perform automatic steering for garage entry, which will be described later.
[0019]
The steering control device 21 includes a control unit 22 and a storage unit 23, and the control unit 22 constitutes an actuator control unit of the present invention, which includes front wheels Wf, based on the rotation angle of the steering wheel 1. Steering angle detection means S ₁ for detecting the steering angle θ of Wf, steering torque detection means S ₂ for detecting the steering torque of the steering wheel 1, and front wheel rotation angle for detecting the rotation angles of the left and right front wheels Wf, Wf Detection means S ₃ , S ₃ , brake operation amount detection means S ₄ for detecting the operation amount (brake operation amount) of the brake pedal 9, and accelerator opening detection for detecting the operation amount (accelerator opening amount) of the accelerator pedal 10 a means S _5, the shift range selected by the select lever 11 ( "D" range, "R" range, "N" range, the "P" range, etc.) and shift range detecting means S ₆ for detecting the Front portion of the vehicle V, the central part and a total of eight object detecting means signals from S ₇ ... and provided on a rear portion is inputted. The object detection means S ₇ is composed of a known sonar, radar, TV camera and the like. The lines connecting the eight object detection means S ₇ ... And the control unit 22 are omitted in order to prevent the drawing from becoming complicated.
[0020]
The front wheel rotation angle detection means S ₃ and S ₃ constituting the movement distance detection means of the present invention outputs a pulse each time the front wheels Wf and Wf rotate by a predetermined angle, and the front wheels Wf and Wf are output at the detected number of pulses. The moving distance X of the vehicle V can be calculated by multiplying a constant determined according to the radius of the vehicle V.
[0021]
Furthermore the control unit 22, the mode selection switch S ₈ and automatic parking start switch S ₉ is operated by the driver are connected. As apparent from FIG. 3, the mode selection switch S ₈ is four parking mode, i.e. reverse parking / right mode, reverse parking / left mode, select one of parallel parking / right mode and parallel parking / left mode It has four switch buttons corresponding to each mode. Automatic parking start switch S ₉ is operated to start automatic parking according to any of the mode selected by the mode selection switch S _8.
[0022]
The storage unit 23 constitutes the movement trajectory setting means of the present invention, which includes the four types of parking mode data, that is, the moving distance X of the vehicle V including the moving direction (forward or reverse) of the vehicle V. The relationship of the reference turning angle θref is stored in advance as a table.
[0023]
Thus, the control unit 22 determines the steering actuator 7 based on the signals from the detection means S _{1 to} S ₇ and the switches S ₈ and S ₉ and the parking mode data stored in the storage unit 23. The operation and the operation of the operation stage teaching device 12 including a liquid crystal monitor, a speaker, a lamp, a chime, a buzzer, and the like are controlled.
[0024]
By the way, when the control unit 22 controls the operation of the steering actuator 7 based on the parking mode data stored in the storage unit 23 and the moving distance X of the vehicle V including the moving direction of the vehicle V, the movement of the vehicle V If the direction cannot be detected correctly, an error occurs in the movement locus and the vehicle V cannot be guided to the target position. Therefore, when the detection of the moving direction of the vehicle V becomes impossible, the control unit 22 stops the automatic steering control.
[0025]
Next, the operation of the embodiment of the present invention having the above-described configuration will be described.
[0026]
During normal not used to automatically steering control (when the automatic parking start switch S ₉ is not ON), the steering control apparatus 21 functions as a general power steering control unit. Specifically, when the driver operates the steering wheel 1 to turn the vehicle V, a steering torque detecting means S ₂ detects the steering torque inputted to the steering wheel 1, the control unit 22 based on the steering torque The driving of the steering actuator 7 is controlled. As a result, the left and right front wheels Wf and Wf are steered by the driving force of the steering actuator 7, and the driver's steering operation is assisted.
[0027]
Next, the content of the automatic steering control will be described by taking the back parking / left mode (a mode in which the vehicle is parked while backing to the parking position on the left side of the vehicle V) as an example.
[0028]
First, as shown in FIG. 2A, the vehicle V is moved to the vicinity of the garage where the vehicle V is to be parked, and a predetermined reference (for example, a door) is set with the left side of the vehicle body as close as possible to the garage entrance line. The vehicle V is stopped at a position (start position {circle around (1)}) where a mark or a side mirror provided inside the vehicle coincides with the center line of the garage. Then, ON the automatic parking start switch S ₉ with to select the back parking / left mode by operating the mode selection switch S ₈ Then, the automatic steering control is started. While the automatic steering control is being performed, the operation stage teaching device 12 switches the current position of the own vehicle, surrounding obstacles, the parking position, the predicted movement trajectory of the own vehicle from the start position to the parking position, and forward to reverse. The turn-back position and the like are displayed, and various instructions and warnings such as operation of the select lever 11 at the turn-back position {circle around (2)} are also given to the driver by sound from the speaker.
[0029]
With the automatic steering control, the driver can loosen the brake pedal 9 and cause the vehicle V to creep, or the accelerator pedal 10 can be slightly depressed to drive the vehicle V without operating the steering wheel 1. the front wheels Wf, Wf are automatically steered based on the data of the selected by the selection switch S ₈ reverse parking / left mode. That is, while the vehicle V moves forward from the start position {circle over (1)} to the turning position {circle around (2)}, the front wheels Wf and Wf are automatically steered to the right, while the vehicle V moves backward from the turning position {circle around (2)} to the target position {circle around (3)} The front wheels Wf, Wf are automatically steered to the left.
[0030]
As apparent from FIG. 2 (B), during automatic steering, the control unit 22 adds the back parking / left mode data read from the storage unit 23 to the front wheel rotation angle detection means S ₃ , S ₃ . The reference turning angle θref is searched by applying the moving distance X of the vehicle V calculated based on the output. And wherein calculating a deviation E (= θref-θ) based on the norm steering angle .theta.ref and the steering angle theta input from the steering angle detecting means S _1, the steering actuator so that the deviation E is zero 7 is controlled. At this time, since the data of the reference turning angle θref is set corresponding to the moving distance 8 of the vehicle V, the moving distance X is correctly detected even if there is some fluctuation in the vehicle speed during the automatic steering control. As long as the vehicle V is moving, the vehicle V always moves on the movement locus.
[0031]
However, in order for the vehicle V to move correctly on the movement locus, the vehicle V travels forward from the start position (1) to the turn-back position (2), and from the turn-back position (2) to the target position (3). V needs to travel backwards. The pulse signals output by the front wheel rotation angle detection means S ₃ and S ₃ are output regardless of whether the vehicle V is traveling forward or backward, and the detected moving distance X is also the moving distance X in the forward direction. or, it is not possible to perform the determination of whether a movement distance X of the reverse direction to confirm the movement direction of the vehicle V by the detected shift range by the shift range detecting means S _6. That is, if the shift range detected between the start position (1) and the turn-back position (2) is the “D” range, it is confirmed that the vehicle V is traveling forward correctly, and the target position from the turn-back position (2) is reached. If the shift range detected up to position {circle around (3)} is the “R” range, it can be confirmed that the vehicle V is traveling backward correctly.
[0032]
The automatic steering control described above, the driver but is released when OFF the mode selecting switch S _8, if the driver also has otherwise operates the steering wheel 1, one of the object detecting means S ₇ is an obstacle When detected, when the vehicle speed exceeds a predetermined value or when the shift range is in the “N” range or the “P” range, the vehicle V moves due to inertia or the inclination of the road surface, and the moving direction is discriminated. When it becomes impossible, it is canceled and returns to normal power steering control.
[0033]
Next, the operation when the moving direction of the vehicle V cannot be determined and the automatic steering control is stopped will be described with reference to the flowchart of FIG.
[0034]
First, when the front wheel rotation angle detection means S ₃ and S ₃ output a pulse signal in step S1 and the movement of the vehicle V is detected, the process proceeds to step S2. If the shift range detected by the shift range detecting means S ₆ at step S2 is the driving range ( "D" range or "R" range), the step S3 it is determined that the moving direction of the vehicle V can be determined Transition. If the shift range is the “D” range in step S3, it is determined in step S4 that the vehicle V is traveling forward. In step S5, the start position {circle around (1)} and the return position are determined based on the back parking / left mode data. Automatic steering of the front wheels Wf, Wf during (2) is executed. If the answer to step S3 is NO and the shift range is the “R” range, it is determined in step S6 that the vehicle V is traveling backward, and in step S5, the return position ▲ based on the back parking / left mode data. Automatic steering of the front wheels Wf, Wf between 2 and the target position (3) is executed.
[0035]
Incidentally, the front wheel rotation angle detecting means S _3, S ₃ is not output the pulse signal at step S1, thus when the movement of the vehicle V is not detected, step S7 in the command to hold the θ current turning angle output In step S5, the turning angle θ of the front wheels Wf, Wf of the vehicle V is maintained as it is.
[0036]
On the other hand, if the detected shift range is stopped range by the shift range detecting means S ₆ in step S2 ( "N" range or the "P" range), it is determined that the moving direction of the vehicle V is indistinguishable Although the process proceeds to step S8, even if the shift range is in the stop range, if a predetermined condition described later is satisfied, it is assumed that the moving direction of the vehicle V can be estimated, and execution of automatic steering is permitted. In this case, it is determined that the moving direction of the vehicle V cannot be determined, and the execution of automatic steering is stopped.
[0037]
That is, when the vehicle V moves despite the shift range being in the stop range in step S8, it is determined whether or not the total movement distance is a predetermined value (for example, 20 cm) or more. If the sum does not reach the predetermined value, the process proceeds to step S9 in order to estimate the moving direction.
[0038]
Previously, if the shift range is the drive range in step S9, i.e., pulses from continuous wheel rotation angle detecting means S _3, S ₃ from a state where the traveling range is selected over the state of stop range is selected If a signal is detected, the process proceeds to step S10. In step S10, if the previous shift range is the “D” range, it is estimated in step S11 that the vehicle V is traveling forward. In step S10, if the previous shift range is the “R” range, in step S12. It is estimated that the vehicle V is traveling backward, and automatic steering is executed in step S5.
[0039]
Specifically, such a case will be described, for example, while the vehicle is traveling forward from the start position (1) to the return position (2) while performing the automatic steering control in the back parking / left mode shown in FIG. If the shift range is switched from the “D” range to the “N” range just before reaching ▼, and the vehicle V travels forward toward the turn-back position (2) due to inertia, the shift range is normally set to “D”. At the moment when the range is switched from the “N” range to the “N” range, the moving direction of the vehicle V becomes indistinguishable and the automatic steering control is stopped, so that the shift range before the shift range is switched to the “N” range is the “D” range. Therefore, even if the current shift range is the “N” range, it is considered that the vehicle V continues to travel forward, and the automatic steering control is stopped. It is continued without a. As described above, even when the shift range is in the stop range, when the moving direction of the vehicle V can be grasped, the automatic steering control is continued unnecessarily by continuing the automatic steering control. It can be avoided to increase convenience.
[0040]
In step S9, if the shift range is not previously in the travel range, that is, if the stop range is continuously selected from the stop state to the moving state of the vehicle V, the process proceeds to step S13. In step S13, since it is impossible to estimate the moving direction of the vehicle V, it is instructed to maintain the current turning angle θ of the front wheels Wf and Wf, and in step S5, the turning angle θ is held. The automatic steering is executed. That is, the movement distance detected in a state where the moving direction of the vehicle V is unknown is ignored, and automatic steering is performed assuming that the movement distance is not detected.
[0041]
Specifically, such a case will be described. For example, the vehicle V is temporarily stopped at the turn-back position (2) in the back parking / left mode shown in FIG. 2, and the pulse signals from the front wheel rotation angle detection means S ₃ and S ₃ are received. If the road surface is downhill when the shift range is switched from the “D” range to the “N” range after the suspension, the vehicle V may move in the forward direction when the brake is released. In this case, even if the pulse signals from the front wheel rotation angle detecting means S _3, S ₃ is output, that the shift range is the vehicle V is determined whether the reverse running whether the forward running to the "N" range Can not. Therefore, in practice even started backward to shift change to "R" range from moving forward by a distance X ₁ in the folded position ▲ 2 ▼ at the "N" range is folded as being backward from the beginning When automatic steering control between the position {circle around (2)} and the target position {circle around (3)} is started, as shown in FIG. 5 (A), automatic steering is performed even during forward movement, and the movement locus of the vehicle V is shown in FIG. 5 (B). As shown by the broken line, there is a possibility that the position is greatly deviated from the target position (3).
[0042]
However, according to the present embodiment, when the moving direction of the vehicle V cannot be grasped, the current turning angle θ of the front wheels Wf and Wf is held assuming that the vehicle V is stopped. As shown by a thick solid line in FIG. 5 (A), automatic steering is not performed at the time of forward movement, and automatic steering is performed after the vehicle V starts to reverse in the “R” range. As indicated by the solid line, the problem can be improved by minimizing the positional deviation from the target position (3).
[0043]
If the total moving distance in the stop range becomes greater than or equal to the predetermined value in step S8, the automatic steering control is stopped in step S14, so that it is prevented from being greatly displaced from the target position (3) as described above. can do.
[0044]
Further, when the moving distance of the vehicle V in the stop range is less than the predetermined value, the execution of the automatic steering control is not prohibited. Therefore, the automatic steering is performed each time when the final deviation at the target position (3) is not greatly affected. Convenience can be improved by avoiding the interruption of control. The moving distance of the vehicle V in the stop range is added during one automatic steering control, and the automatic steering control is stopped when the added value is equal to or greater than the predetermined value. For example, if the vehicle V moves 10 cm in the “P” range at the start position {circle over (1)} and the vehicle V moves 10 cm in the “N” range at the subsequent turn-back position {circle around (2)}, the total moving distance reaches 20 cm. Therefore, the automatic steering control is stopped. Thereby, it is possible to reliably prevent the vehicle V from moving to an unintended place by the automatic steering control.
[0045]
As mentioned above, although the Example of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.
[0046]
For example, in the embodiment, the movement locus of the vehicle V up to the target position is stored in the storage unit 23 in advance, but the movement locus can be calculated from the current position and the target position of the vehicle V. Also in the case where in the step S2 of the flowchart of FIG. 4 running range is not detected not only when the stop range is detected, if the shift range detecting means S ₆ is the shift range out of order it becomes undetectable is included.
[0047]
【The invention's effect】
As described above, according to the first aspect of the present invention, when the vehicle moves when the shift range detecting means does not detect the travel range, it can be determined whether the moving direction is forward or reverse. Therefore, automatic steering control cannot be performed accurately based on the movement trajectory set by the movement trajectory setting means. In such a case, the actuator control means stops driving the actuator and the vehicle is expected. It is possible to avoid moving in an unforeseen direction.
[0048]
According to the second aspect of the present invention, if the moving distance of the vehicle when the shift range detection means does not detect the travel range is less than a predetermined value, the actuator control means does not stop driving the actuator. Therefore, it is possible to improve convenience by avoiding that the automatic steering control is interrupted each time the vehicle is moved slightly so as not to greatly affect the deviation of the target position.
[0049]
According to the invention described in claim 3, when it is possible to determine the moving direction of the vehicle even if the shift range is not in the travel range, the actuator control means continues driving the actuator, Convenience can be improved by avoiding the automatic steering control being stopped unnecessarily.
[0050]
According to the fourth aspect of the present invention, when the moving direction of the vehicle cannot be determined even if the vehicle moves, the control is performed by assuming that the vehicle is stopped, thereby driving the actuator. Can be reliably stopped to prevent the vehicle from moving in an unexpected direction.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a vehicle equipped with an automatic steering device. FIG. 2 is an explanatory diagram of the operation of a back parking / left mode. FIG. 3 is a diagram showing a mode selection switch and an automatic parking start switch. Flow chart [Fig. 5] Illustration of action
7 Steering actuator (actuator)
22 Control unit (actuator control means)
23 storage unit (movement trajectory setting means)
S ₃ Front wheel rotation angle detection means (movement distance detection means)
S ₆ Shift range detection means V Vehicle Wf Front wheel (wheel)
X Travel distance θ Steering angle

Claims (4)

An actuator (7) for steering the wheel (Wf);
Shift range detecting means (S ₆ ) for detecting the shift range of the automatic transmission mounted on the vehicle (V);
A moving distance detecting means (S ₃ ) for detecting a moving distance (X) of the vehicle (V);
Movement trajectory setting means for storing or calculating the movement trajectory of the vehicle (V) to the target position as the relationship of the turning angle (θ) of the wheel (Wf) to the movement distance (X) including the movement direction of the vehicle (V). (23)
The driving of the actuator (7) is controlled based on the movement trajectory stored or calculated by the movement trajectory setting means (23) and the movement distance (X) of the vehicle (V) detected by the movement distance detection means (S ₃ ). An actuator control means (22);
In an automatic steering device for a vehicle equipped with
When the movement distance detection means (S ₃ ) detects the movement distance (X) of the vehicle (V) when the shift range detection means (S ₆ ) does not detect the travel range, the actuator control means ( 22) An automatic steering apparatus for a vehicle, wherein driving of the actuator (7) based on the movement locus and the movement distance (X) is stopped. When the movement distance detection means (S ₃ ) detects a movement distance (X) of the vehicle (V) that is equal to or greater than a predetermined value when the shift range detection means (S ₆ ) does not detect a travel range, The automatic steering device for a vehicle according to claim 1, wherein the actuator control means (22) stops driving the actuator (7). When the shift range detecting means (S ₆ ) changes from the state in which the traveling range is detected to the state in which the traveling range is not detected, the moving distance detecting means (S ₃ ) continues and the vehicle (V) When the movement distance (X) is detected, the actuator control means (22) controls the driving of the actuator (7) by assuming that the detected travel range is continuously established. The automatic steering device for a vehicle according to claim 1, wherein the automatic steering device is used. When the movement distance detection means (S ₃ ) detects the movement distance (X) of the vehicle (V) when the shift range detection means (S ₆ ) does not detect the travel range, the actuator control means ( 22) ignores the detected moving distance (X) of the vehicle (V), and considers that the vehicle (V) is not moving, and controls the driving of the actuator (7). The automatic steering device for a vehicle according to any one of claims 1 to 3.

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