JPH11198843A - Automatic vehicle steering system - Google Patents

Abstract

(57) [Problem] To surely prevent a vehicle from moving in an unexpected direction when a moving distance detecting means of an automatic steering device fails. A based on a pulse of the same wheel two front wheel rotational angle detecting means provided in Sa _3, Sb ₃ outputs, first, second moving distance detecting means 13a, 13b are two moving distance Xa, and Xb To detect. The comparing means 14 compares the two moving distances Xa and Xb, and when the difference or ratio between the two is outside a predetermined range, the two front wheel rotation angle detecting means S
It is determined that one of a ₃ and Sb ₃ has failed. In this case, the automatic steering control stopping means 16 outputs an automatic steering control stop command signal to the steering actuator driving means 17, thereby stopping the automatic steering control and preventing the vehicle from moving in an unexpected direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic vehicle steering system for automatically parking a vehicle without relying on a driver's steering operation.

[0002]

2. Description of the Related Art An automatic steering apparatus for such a vehicle is disclosed in Japanese Patent Laid-Open Publication No.
No. 74256 and JP-A-4-55168. The automatic steering devices for these vehicles use an actuator of a conventionally known electric power steering device, and control the actuator based on a relationship between a moving distance of the vehicle and a steering angle stored in advance to control the back parking or the like. Parallel parking is performed automatically.

[0003]

By the way, in the prior art, the driving of the actuator is controlled so that the turning angle of the vehicle coincides with a reference turning angle stored in advance corresponding to the moving distance of the vehicle. However, if the moving distance detecting means for detecting the moving distance of the vehicle breaks down, there is a problem that the vehicle cannot be moved along the target moving path. For example, if the moving distance detected by the moving distance detecting means fails during the automatic steering control is held at a constant value,
In practice, the control device erroneously recognizes that the vehicle is stopped despite the vehicle is moving, and holds the reference steering angle, so that the vehicle may move in an unexpected direction.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to surely prevent a vehicle from moving in an unexpected direction when a moving distance detecting means of an automatic steering device fails. I do.

[0005]

In order to achieve the above object, according to the present invention, there is provided a trajectory setting means for storing or calculating a trajectory of a vehicle to a target position;
An actuator for steering wheels, a moving distance detecting means for detecting a moving distance of the vehicle, and an actuator for driving the actuator in accordance with the moving distance of the vehicle detected by the moving distance detecting means to move the vehicle along the moving trajectory. In an automatic steering apparatus for a vehicle having an actuator control unit for controlling, a moving distance detecting unit includes a first moving distance detecting unit and a second moving distance detecting unit, and the actuator controlling unit includes the first and second moving units. The control of the actuator based on the movement trajectory is stopped when the outputs of the distance detecting means do not match.

According to the above construction, the first moving distance detecting means and the second moving distance detecting means respectively detect the moving distance of the vehicle, and when the outputs of the two moving distance detecting means do not match, any one of the moving distances is detected. Since the control of the actuator based on the movement trajectory is stopped by determining that the detection means is out of order, the automatic steering control based on the incorrect movement distance is performed and the vehicle is reliably prevented from moving in an unexpected direction. can do.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, at least one of the first and second moving distance detecting means includes a vehicle speed detecting means for detecting a vehicle speed. I do.

[0010] According to the above configuration, by using the vehicle speed detecting means provided as standard in the vehicle as the moving distance detecting means, the number of parts can be reduced and the cost can be reduced.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the actuator control means includes a difference between the two movement distances detected by the first and second movement distance detection means. Alternatively, the control of the actuator based on the movement trajectory is stopped when the ratio is out of the predetermined range.

According to the above configuration, by comparing the difference or ratio of the two moving distances detected by the first and second moving distance detecting means with the predetermined range, the failure is accurately determined and the control of the actuator is performed. Can be stopped exactly.

According to a fourth aspect of the present invention, in addition to the configuration of the third aspect, the first and second moving distance detecting means detects a moving distance based on a rotation angle or a rotation speed of the same wheel. It is characterized by the following.

According to the above configuration, the first and second moving distance detecting means detect the moving distance based on the rotation angle or the rotation speed of the same wheel, so that the failure determination can be performed more accurately.

According to a fifth aspect of the present invention, in addition to the configuration of the first or second aspect, the first and second moving distance detecting means move based on the rotation speed or rotation speed of each separate wheel. The actuator control means detects the distance, and when the relation between the outputs of the first and second movement distance detection means is not a predetermined relation determined according to the movement trajectory, the actuator control means detects the distance based on the movement trajectory. The control is stopped.

According to the above arrangement, even if the first and second moving distance detecting means detects the moving distance based on, for example, the rotational speed or rotational speed of the left or right or front and rear different wheels, the first and second moving distance detecting means can be used. By comparing the output relationship of the two-movement-distance detecting means with a predetermined relationship determined according to the movement trajectory, it is possible to accurately perform a failure determination and accurately stop the actuator control.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

FIGS. 1 to 4 show a first embodiment of the present invention. FIG. 1 is an overall configuration diagram of a vehicle provided with a steering control device.
FIG. 2 is a diagram illustrating the operation of the back parking / left mode, FIG. 3 is a diagram illustrating a mode selection switch and an automatic parking start switch, and FIG. 4 is a block diagram of a control system.

As shown in FIG. 1, the vehicle V has a pair of front wheels W
f, Wf and a pair of rear wheels Wr, Wr. The steering wheel 1 and the front wheels Wf, Wf, which are the steered wheels,
A steering shaft 2 that rotates 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, left and right tie rods 5, 5 provided at both ends of the rack 4, and a tie rod 5 , 5 are connected by left and right knuckles 6, 6. A steering actuator 7 composed of an electric motor is connected to the steering shaft 2 via a worm gear mechanism 8 in order to assist the driver in operating the steering wheel 1 or to perform automatic steering for garage described later.

The steering control device 21 includes a control unit 22 and a storage unit 2
3 which are composed of, the control unit 22, and the steering angle detecting means S ₁ for detecting a steering angle θ of the front wheels Wf based on a rotation angle of the steering wheel 1, detects the steering torque of the steering wheel 1 Steering torque detecting means S ₂
Left or right front wheel Wf, Wf (for example, left front wheel W
f) Two front wheel rotation angle detecting means Sa for detecting the rotation angle
₃ , Sb ₃ , brake operation amount detecting means S ₄ for detecting the operation amount of the brake pedal 9, and the shift range (“D” range, “R” range, “N” range, “N”) selected by the select lever 10. the shift range detecting means S ₅ for detecting the P "range, etc.), the front of the vehicle V, the central portion and the signal from the total of eight object detecting means S ₆ ... and provided on a rear portion is inputted. The object detecting means S ₆ comprises a known sonar, radar, television camera or the like. In addition, 8
Lines connecting the individual object detecting means S ₆ to the control unit 22 are omitted to avoid complication of the drawing. The control unit 22 constitutes an actuator control unit of the present invention, and the storage unit 23 constitutes a movement locus setting unit of the present invention.

As is apparent from FIG.
Mode selection switch S ₇ and automatic parking start switch S ₈ is operated by the driver is connected to the control unit 22. Mode selection switch S _7, the four types of parking mode, which will be described later, that is the back parking / right mode, the back parking /
It has four buttons operated when selecting any of the left mode, the parallel parking / right mode, and the parallel parking / left mode. Automatic parking start switch S ₈ is operated to start automatic parking according to any of the mode selected by the mode selection switch S _7.

The storage unit 23 stores in advance a table of the data of the four types of parking modes, that is, the relationship of the reference turning angle θref to the moving distance X of the vehicle V.

The control unit 22 includes the detection means S _{1 to} S _6.
Based on the signals from the switches S ₇ and S ₈ and the parking mode data stored in the storage unit 23, the operation of the steering actuator 7 and the operation including the liquid crystal monitor, speaker, lamp, chime, buzzer, etc. The operation of the step teaching device 11 is controlled.

FIG. 4 shows the structure of a part of the control unit 22 which controls the steering actuator 7.

The two front wheel rotation angle detecting means Sa ₃ , S
b ₃ are both and outputs a pulse signal by detecting the proximity of a plurality of dogs projecting from the outer periphery of the rotor rotating with the left front wheel Wf of the axle. One of the front wheel rotation angle detecting means Sa ₃ and Sb ₃ is used in advance as a vehicle speed detecting means.
The rotational speed of the front wheel Wf (that is, the vehicle speed) is detected from the number of pulses per unit time.

Two front wheel rotation angle detecting means Sa ₃ , Sb ₃
Includes first moving distance detecting means 13a and second moving distance detecting means 13a
The moving distance detecting means 13b is connected. The first and second moving distance detecting means 13a and 13b calculate the rotation angle of the front wheel Wf from the integrated value of the pulses respectively output by the two front wheel rotation angle detecting means Sa ₃ and Sb ₃ and calculate the rotation angle of the front wheel Wf. By multiplying the rotation angle by the known circumference of the front wheel Wf, 2 is obtained.
The two moving distances Xa and Xb are detected.

The comparing means 14, to which the two moving distances Xa and Xb are input, compares the two moving distances Xa and Xb to determine whether the two front wheel rotation angle detecting means Sa ₃ and Sb ₃ are functioning normally. Determine whether or not. If the two front wheel rotation angle detecting means Sa ₃ and Sb ₃ are both normal, the high and low select values of the two moving distances Xa and Xb are calculated.
Alternatively, the average value is selected as the moving distance X of the vehicle V,
The reference turning angle θref (see FIG. 2B) read from the storage unit 23 based on the moving distance X is used as the deviation calculating means 1.
5 is input. The deviation calculating means 15 calculates the reference turning angle θre.
f and the deviation E between the turning angle θ detected by the turning angle detecting means S _1.
(= Θref−θ), and the steering actuator driving means 17 controls the operation of the steering actuator 7 so that the deviation E becomes zero. At this time,
Since the data of the reference turning angle θref is set in accordance with the moving distance X of the vehicle V, the vehicle V always moves on the movement locus even if there is some fluctuation in the vehicle speed of the creep running. .

On the other hand, in the comparing means 14,
Front wheel rotation angle detecting means Sa_Three, Sb _ThreeIs determined to have failed
Then, the automatic steering control stopping means 16
Automatic steering control stop command signal to the actuator driving means 17
Is output.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

[0028] Usually when not performing the automatic parking (when the mode selecting switch S ₇ is not operated), 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, Wf are steered by the driving force of the steering actuator 7, and the steering operation of the driver is assisted.

Next, the contents of the automatic steering control will be described by taking a back parking / left mode (a mode in which the vehicle is parked while backing at a parking position on the left side of the vehicle V) as an example.

First, as shown in FIG. 2A, the driver moves the vehicle V to the vicinity of the garage to be parked by the driver's own steering operation, and keeps the left side of the vehicle body as close to the garage entrance line as possible. Predetermined criteria (for example, marks or side mirrors inside doors)
Stops the vehicle V at a position (start position) that coincides with the center line of the garage. Then, ON the automatic parking start switch S ₈ with to select the back parking / left mode by operating the mode selection switch S ₇ Then, the automatic steering control is started. While the automatic steering control is being performed, the operation stage teaching device 11 switches the current position of the own vehicle, surrounding obstacles, the parking position, the expected movement trajectory of the own vehicle from the start position to the target position, and forward to reverse. The turning position and the like are displayed, and various instructions and warnings such as operation of the select lever 10 at the turning position are given to the driver by voice from the speaker.

[0031] by the automatic steering control, driver of alone without operating the steering wheel 1, which is selected by the mode selection switch S ₇ back parking / left mode to creep running the vehicle V loosen the brake pedal 9 data , The front wheels Wf, Wf are automatically steered. That is, the front wheels Wf, Wf are automatically steered to the right while the vehicle V moves forward from the start position to the turning position, and the front wheels Wf, Wf are automatically steered to the left while the vehicle V moves backward from the turning position to the target position. .

As is apparent from FIG. 2B, during the automatic steering, the control unit 22 reads the reference steering angle θref of the back parking / left mode read from the storage unit 23 and detects the steering angle. calculates the deviation E (= θref-θ) based on the steering angle theta detected by means S _1, the deviation E to control the operation of the steering actuator 7 so that 0.

Since the above-mentioned automatic steering control is performed while the driver depresses the brake pedal 9 and the vehicle V is creeping, the driver depresses the brake pedal 9 immediately when the driver finds an obstacle. Can be stopped.

The automatic steering control described above, the driver but is released when OFF the mode selecting switch S _7, if the driver also has otherwise takes his foot from the brake pedal 9, the driver operates the steering wheel 1 If any one of the object detecting means S ₆ detects an obstacle, the first and second moving distance detecting means 13a, 13
If the output of b does not match, it is released and returns to normal power steering control.

Next, the first and second moving distance detecting means 13
The suspension of the automatic steering control when the outputs of a and 13b do not match will be further described.

On the outer periphery of the rotor rotating with the left front wheel Wf
Two front wheel rotation angle detection hands for a plurality of protruding dogs
Step Sa_Three, Sb_ThreeAngle detection for both front wheels according to the mounting phase
Outgoing means Sa_Three, Sb_ThreeTemporarily increases the number of pulses detected by
Pulse difference may occur, but the difference is 0 pulse
Alternatively, in the case of one pulse, both front wheel rotation angle detecting means S
a _Three, Sb_ThreeCan be determined to be functioning properly
When the difference becomes two or more pulses, one of the front wheel rotations
Shift angle detecting means Sa_Three, Sb_ThreeTo determine that has failed
Can be.

In FIG. 4, two moving distances Xa and Xb detected by the first and second moving distance detecting means 13a and 13b based on the rotation angle of the front left wheel Wf are input to a comparing means 14 and compared. . At this time, the two moving distances Xa, X output by the first and second moving distance detecting means 13a, 13b are output.
If the difference b is less than the distance corresponding to two pulses, both front wheel rotation angle detection means Sa ₃ and Sb ₃ are normal. If the difference b is more than the distance corresponding to two pulses, both front wheel rotation angle detection means Sa _3. , Sb ₃ have failed.

As described above, both front wheel rotation angle detecting means Sa ₃ ,
If it is determined that any one of Sb ₃ has failed, if a high select value, a low select value, or an average value of both moving distances Xa and Xb is used as the moving distance X, an error in the moving distance X automatically Steering control cannot be performed accurately, and the trajectory of the vehicle V may deviate from the reference trajectory. Therefore, the automatic steering control stopping means 16 is switched to the steering actuator driving means 17.
By outputting the automatic steering control stop command signal to stop the automatic steering control, it is possible to prevent the vehicle V from moving in an unexpected direction. At this time, the operation stage teaching device 11 notifies the driver that the automatic steering control has been stopped by voice from a speaker.

In the above-described embodiment, the two moving distances X detected by the first and second moving distance detecting means 13a and 13b are used.
Failure determination is performed when the difference between a and Xb exceeds a predetermined value corresponding to two pulses of the output of the front wheel rotation angle detection means Sa ₃ and Sb ₃ .
When the ratio Xa / Xb of Xb is, for example, Xa / Xb ≧ 1.05 or Xa / Xb ≦ 0.95, or when one of the two moving distances Xa and Xb changes but the other does not change. Failure determination may be performed.

Next, a second embodiment of the present invention will be described with reference to FIGS.

In the first embodiment described above, the two front wheel rotation angle detecting means Sa ₃ and Sb ₃ are the same wheel (left front wheel Wf).
(See FIG. 1), but in the second embodiment, two front wheel rotation angle detecting means Sa ₃ and Sb ₃ are provided on the left and right wheels (left front wheel Wf and right front wheel Wf), respectively. When the vehicle V runs straight, the failure determination of the front wheel rotation angle detecting means Sa ₃ and Sb ₃ can be performed in the same manner as in the first embodiment. Since the trajectories of the inner rings do not match, an accurate failure determination cannot be made by simply comparing the two moving distances Xa and Xb detected by the first and second moving distance detecting means 13a and 13b.

For example, as shown in FIG. 5, when the vehicle V turns backward by turning the steering wheel 1 to the left, the front wheel rotation angle detecting means Sa ₃ provided on the left front wheel Wf, which is the turning inner wheel, is used.
Moving distance Xa of the first moving distance detecting unit 13a detects on the basis of the output of the second moving distance detecting unit 13b based on the output of the front wheel rotation angle detecting means Sb ₃ provided in the right front wheel Wf is the outer turning wheel is It becomes smaller than the detected moving distance Xb.

The graph of FIG. 6A shows that the vehicle V corresponds to FIG.
The relationship between the moving distance Xa of the turning inner wheel (left front wheel Wf) and the moving distance Xb of the turning outer wheel (right front wheel Wf) when the vehicle moves backward from the turnback position of (A) to the target position is shown. When the vehicle V is at the turning position (point a), the steering angle θ is 0, and as the vehicle V moves backward, the steering wheel 1 is steered to the left from the neutral position, and b
The turning angle θ that has reached the maximum value at the point is maintained at the maximum value up to the point c. As the vehicle V further moves backward toward the target position (point d), the steering wheel 1 is steered rightward toward the neutral position, and the steered angle θ decreases from the maximum value to zero. Meanwhile, the two moving distances Xa and Xb are Xa = f
It changes based on the function of (Xb).

That is, when the vehicle V moves backward from the turning position shown in FIG. 2A to the target position, if the two front wheel rotation angle detecting means Sa ₃ and Sb ₃ are both normal, the first and second movements are performed. 2 detected by the distance detecting means 13a and 13b
The two moving distances Xa and Xb are Xa = f in FIG.
It should satisfy the relationship of (Xb). Therefore, an error corresponding to the allowable detection error of the two moving distance detecting means 13a and 13b is E ₀ (for example, 20 cm), and the relationship between the two moving distances Xa and Xb is f (Xb) −E ₀ <Xa <. f
When (Xb) + E ₀ is satisfied, a normality determination is made, and Xa ≦
f (Xb) -E ₀ or Xa ≧ Xa <f (Xb) + E
_In the case of ₀ (see the hatched portion in FIG. 6B), the failure determination is performed, so that the front wheel rotation angle detection means Sa ₃ and Sb ₃ can be provided on the left and right front wheels Wf and Wf respectively. The failure determination of Sa ₃ and Sb ₃ can be accurately performed.

Although the embodiment of the present invention has been described above, various design changes can be made in the present invention without departing from the gist thereof.

For example, in the embodiment, the vehicle V
Is stored in the storage unit 23 in advance, but it is also possible to calculate the movement trajectory from the current position and the target position of the vehicle V. In the second embodiment, the left and right front wheels W
The front wheel rotation angle detection means Sa ₃ , Sb ₃
However, it is also possible to provide rotation angle detecting means for each of the front and rear wheels, and make a failure determination by comparing the moving distances obtained from each of them.

As a modification of the first embodiment, dXa / dt and dXb / are the rates of change of the two moving distances Xa and Xb.
dt, and when the difference or ratio between the two deviates from a predetermined range, a failure determination can be made. Further, as a modification of the second embodiment, a function of the two rates of change dXa / dt and dXb / dt Failure determination can be performed when the relationship deviates from a predetermined range determined according to the movement locus of the vehicle V.

The vehicle speed detecting means provided in advance in the vehicle V to detect the vehicle speed is replaced by first and second moving distance detecting means 13.
The cost can be reduced by using at least one of a and 13b. Since the moving distance of the vehicle V is an integral value of the vehicle speed, the vehicle speed detecting means can be substantially diverted as the moving distance detecting means.

[0049]

As described above, according to the first aspect of the present invention, the first moving distance detecting means and the second moving distance detecting means detect the moving distance of the vehicle, respectively. When the outputs do not match, it is determined that one of the moving distance detecting means is out of order and the control of the actuator based on the moving trajectory is stopped. Movement in an unexpected direction can be reliably prevented.

According to the second aspect of the present invention,
By using the vehicle speed detecting means provided as standard in the vehicle as the moving distance detecting means, the number of parts can be reduced and the cost can be reduced.

According to the third aspect of the present invention,
By comparing the difference or ratio between the two moving distances detected by the first and second moving distance detecting means with a predetermined range, it is possible to accurately determine a failure and to appropriately stop the control of the actuator.

According to the fourth aspect of the present invention,
The first and second moving distance detecting means detects the moving distance based on the rotation angle or the rotation speed of the same wheel,
Failure determination can be performed more accurately.

According to the fifth aspect of the present invention,
Even if the first and second moving distance detecting means detect the moving distance based on the number of rotations or the rotational speeds of the left and right or front and rear different wheels, the relationship between the outputs of the first and second moving distance detecting means is determined. By comparing with a predetermined relationship determined according to the movement trajectory, it is possible to accurately perform a failure determination and accurately stop the control of the actuator.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a vehicle including a steering control device.

FIG. 2 is an explanatory diagram of an operation in a back parking / left mode.

FIG. 3 is a diagram showing a mode selection switch and an automatic parking start switch.

FIG. 4 is a block diagram of a control system.

FIG. 5 is a diagram for explaining a difference in a moving distance between a turning inner wheel and a turning inner wheel.

FIG. 6 is a graph showing a relationship between two moving distances Xa and Xb.

[Explanation of symbols]

7 Steering actuator (actuator) 13a First moving distance detecting means (moving distance detecting means) 13b Second moving distance detecting means (moving distance detecting means) 22 Control unit (actuator controlling means) 23 Storage unit (moving locus setting means) Vehicle Wf Front wheel (wheel) X Moving distance Xa Moving distance Xb Moving distance

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B62D 119: 00

Claims (5)

[Claims] 1. A trajectory setting means (23) for storing or calculating a trajectory of a vehicle (V) to a target position, an actuator (7) for turning a wheel (Wf), and a movement of the vehicle (V). A moving distance detecting means (13a, 13b) for detecting the distance (X); and a vehicle (V) detected by the moving distance detecting means (13a, 13b) to move the vehicle (V) along the moving locus.
And an actuator control means (22) for controlling the driving of the actuator (7) according to the moving distance (X) of the vehicle, wherein the moving distance detecting means (13a, 13b) comprises a first moving distance. Detecting means (13a) and second moving distance detecting means (13
b) said actuator control means (22)
Are the first and second moving distance detecting means (13a, 13
An automatic steering device for a vehicle, wherein the control of the actuator (7) based on the movement trajectory is stopped when the outputs of (b) do not match. 2. The first and second moving distance detecting means (13).
2. The automatic steering apparatus for a vehicle according to claim 1, wherein at least one of a, 13b) includes a vehicle speed detection unit that detects a vehicle speed. 3. The actuator control means (22).
Are the first and second moving distance detecting means (13a, 13
The control of the actuator (7) based on the movement trajectory is stopped when a difference or a ratio between the two movement distances (Xa, Xb) detected in b) is out of a predetermined range. Or the automatic steering device for a vehicle according to 2. 4. The first and second moving distance detecting means (13)
4. The automatic steering apparatus for a vehicle according to claim 3, wherein a, 13b) detects the moving distance (X) based on a rotation angle or a rotation speed of the same wheel (Wf). 5. The first and second moving distance detecting means (13).
a, 13b) are for detecting the moving distance (X) based on the number of rotations or the rotating speeds of the separate wheels (Wf), respectively, and the actuator control means (22) is for detecting the first and second moving distances. The control of the actuator (7) based on the movement trajectory is stopped when the output relation of the detection means (13a, 13b) does not have a predetermined relation determined according to the movement trajectory. 3. The automatic steering device for a vehicle according to 2.