JPH03113515A - Steering controller for switchback of vehicle - Google Patents

Abstract

PURPOSE:To position a vehicle even in a limited space with high accuracy and high efficiency by deciding a vehicle shift distance in a switchback action based on the position and the attitude of the vehicle set at the start of shift of the vehicle and at the same time repeating the switchback action until the position and the attitude of the vehicle are set under each prescribed allowable level. CONSTITUTION:An image pickup means 1 is provided to photograph the surface of a traveling route of a vehicle together with an attitude position calculation means 3 which calculates the attitude and the position of the vehicle based on the picture information obtained via the means 1, a distance calculation means 5 which calculates the distance between the vehicle and a prescribed position, and a switchback means 7 which repeats the switchback action to a prescribed position until the position and the attitude of the vehicle are set under each prescribed allowable level. Then a switchback deciding means 9 decides a shift distance of the vehicle in a switchback action based on the position and the attitude of the vehicle set when the shift of the vehicle is started. In such a constitution, the vehicle is positioned even in a limited space with high accuracy and high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a vehicle reversing steering control device that controls the reversing steering of an unmanned vehicle to bring it closer to a predetermined position.

(Prior Art) As an abroaching method for bringing a vehicle closer to a station, which is a predetermined position at which a vehicle is to be stopped, a guide line such as a light reflective tape, magnetic wire, or separable mark is drawn to the station, and the conveyor vehicle is moved along the guide line. There are methods such as controlling the steering to guide the vehicle, making the vehicle contact the station to obtain stopping accuracy at the station, and providing a locking mechanism on the vehicle or the floor.

(Problems to be Solved by the Invention) As described above, in the conventional method of controlling the steering so as to guide the vehicle along the guide line, when traveling along the guide line with a large curvature, the vehicle winds in a meandering manner. There was a problem with putting it away.

Furthermore, conventionally, in order to improve positioning accuracy, a contact wall is provided at the station or a locking mechanism is provided on the vehicle or the floor, so there is a problem that a smooth approach cannot be made.

The present invention has been made in view of the above, and an object of the present invention is to provide a turning steering control device for a vehicle that can perform an appropriate turning operation so as to smoothly approach a predetermined position.

[Structure of the Invention] (Means for Solving the Problem) In order to achieve the above-mentioned object, as shown in FIG. A turning steering control device for a vehicle that approaches a vehicle, comprising: an image capturing means 1 for capturing an image of a road surface of a running road; an attitude position calculating means 3 for calculating a vehicle attitude and a vehicle position based on image information captured by the image capturing means; distance calculation means 5 for calculating the distance of the vehicle to the predetermined position;
a switching means 7 which repeats a switching operation to a predetermined position until the vehicle posture and vehicle position are within predetermined tolerance values; The gist thereof is to have a turning distance determining means 9 for determining the turning distance.

(Function) In the turning steering control device of the present invention, the vehicle movement distance in the turning operation is determined based on the vehicle attitude and the vehicle position at the start of movement, and the vehicle attitude and the vehicle position are determined until the vehicle attitude and the vehicle position are within a predetermined tolerance value. Repeatedly switching back to position.

(Example) Hereinafter, the present invention will be explained in detail using the drawings.

As shown in FIG. 2, an unmanned vehicle to which a steering control device according to an embodiment of the present invention is applied is equipped with a camera 11 in a vehicle body 10, and guide lines drawn on both sides of the road surface of a traveling path 12. The vehicle travels along a route along the white line 13 while taking images of the white line 13 at a predetermined control cycle.

As shown in FIG. 3, the vehicle steering control device according to an embodiment of the present invention inputs an image signal of a white line, etc. imaged by the camera 11, forms image data, and calculates the distance from the white line. an image processing device 21 that detects the vehicle attitude indicated by the indicated position coordinates and the tangential angle of the point; a map information section 23 that indicates the distance of the path to be traveled; and a travel control section 25 that determines the movement target point. , the image processing device 21
, a steering control section 27 that estimates and calculates the steering angle to the target point from information from the map information section 23 and the travel control section 25, and a steering output parameter section 29 that determines the steering output angle.
It is comprised of a mileage control section 31 that determines the mileage, and a motor drive section 33 that drives a motor to move the vehicle by the distance determined by the mileage control section 31.

Next, the effect will be explained.

First, as shown in FIG. 4, a vehicle 10 that is an automatic guided vehicle
The white line 13 is imaged by the camera 11, and from this image signal, the image processing device 21 calculates the vehicle attitude θS, which is the tangential angle of the vehicle 10 to the white line 13 in the traveling direction, and the position of the vehicle 10, from the white line 13. Detect the distance dX. Also, white line 1 from the center of the front wheel (drive wheel)
Let the distance between the three points be dx (-f(dx, θS)).

Next, as shown in FIG. 5, the vehicle 10 that has traveled on the route to approach station S1, which is a predetermined target point, captures an image with the camera 11 at point A1, and the vehicle attitude θS is determined.

and distance dx+ are detected. Also, at this time, y to the station S obtained from the travel control section 25
Let dy be the traveling distance in the axial direction.

Each data θs+, dx+ and dy obtained in this way
From then on, steering travel is performed with station S as the target point using fuzzy steering control, and image input is performed at the stopping point.In this case, the allowable value of the vehicle state at station S point is determined by θSS and dxss, if these stop tolerance values are exceeded due to road surface conditions, output errors, etc., the obtained input value dyiSdxi
, θsi is used to perform fuzzy steering control for reversing with the target point S, and image input is performed at the stopping point. And again,
If the stop tolerance is exceeded, the forward fuzzy steering control toward the target point S is performed again.
If the stopping point is 8 points, as is (dyi=c and S°
It advances by dyi from the point (dy 1 = dy') and finally stops.

The flow of such a switching operation is shown as a flowchart in FIG. 7, and its repeated operation is illustrated in FIG.

Here, the turning width dy i (-I dy (N
) l) is dy (N)=dy (N-1)-α(
N), and the switching width is gradually reduced.

This turning width will be explained with reference to FIGS. 9(a) and 9(b). First, in FIG. 9(a), the vehicle 10 is a
Assume that as a result of approaching the target point S by moving forward from the position (0), the position a(1) is reached. As a result,
Vehicle attitude θ5 (1) and distance dx (1) are the allowable values θ
If it is not within SS and dxss, further switching is performed. In this case, for example, subtracting an arbitrary distance α from the distance dy(0) to gradually reduce the turning distance dy(N) is performed in a normal turning operation. However, if this distance α is arbitrarily determined,
911 As shown in (a), because the steering operation is performed too rapidly (dx (1) becomes smaller, the steering operation becomes larger), as shown in the same figure, the vehicle 10 and the adjacent The possibility of colliding with a vehicle, etc. increases.

Therefore, as shown in FIG. 9(b), the value of the distance α is determined by providing a function f that changes according to the vehicle attitude θ5 (1) and the distance dx (1), and the sudden steering operation is dy(N) is determined such that the process is not performed. As a result, as shown in FIG. 9(b), it is possible to approach without colliding with the side wall 9 or an adjacent vehicle.

Here, the membership function, control rule, and function f for determining the α value in steering control are set depending on the road surface condition and surrounding conditions (side walls, etc.). That is, in FIG. 9(b), this function f is expressed by the following equation.

a (N)-g-dx(N) + h-θ5(N)+
fL·dw(N) Here, dw(N) is the distance to the side wall measured by a sensor such as an ultrasonic sensor attached to the vehicle. This means that the larger Idx(N)l is, the larger θs(N) is in the positive direction, and the smaller dw(N) is, the smaller the a(N) value is, and the smaller 1dx(N)l is.
This is a function in which α(i) increases as θs (N) increases in the negative direction and dw(N) increases.

In this way, the steering output parameters (control rules) can be determined depending on the situation, such as whether there is a side wall nearby or the road is sloping, making it extremely effective for approaches with restrictions such as entering a narrow garage. be.

[Effects of the Invention] As explained above, according to the present invention, the distance traveled by the vehicle in a turnback operation is determined based on the vehicle attitude and vehicle position at the start of the movement, while the vehicle attitude and the vehicle position are determined to be within predetermined tolerance values. Since the operation of switching back to a predetermined position is repeated until the line is within It can accurately approach a predetermined position, eliminate unnecessary turnarounds, and position accurately and efficiently even in a restricted space.

[Brief explanation of drawings]

Figure 1 is a claim correspondence diagram of the present invention, and Figure 2 is a diagram of the claims of the present invention.
・A side explanatory view showing a model of a vehicle to which a turning steering control device according to an embodiment is applied; FIG. 3 is a block diagram showing the configuration of a turning steering control device for a vehicle according to an embodiment of the present invention; FIG. An explanatory diagram showing the vehicle attitude θS, which is the tangential angle of the vehicle's traveling direction to the white line, and the distance dx from the white line, which is the vehicle position. Fig. 5 is an explanatory diagram showing the approach of the vehicle to the target point. Fig. 6 is the target point. An explanatory diagram showing the permissible value of the vehicle state at a point, FIG. 7 is a flowchart showing the operation of the vehicle turning steering control device of FIG. 3, FIG. 8 is an explanatory diagram of the operation of FIG. 7, and FIG. It is an explanatory view showing width determination. 11...Camera 21...Image processing device 0 3...Map information unit 5...Traveling control unit 7...Steering control 1 unit 9...Steering output parameter unit 1...Driving distance control Section 3...Motor drive section

Claims (1)

[Claims] A steering control device for a vehicle that controls steering of an unmanned vehicle to bring it closer to a predetermined position, the device comprising: an imaging means for taking an image of a road surface of a traveling route; and a vehicle attitude and a vehicle position based on image information taken by the imaging means. Attitude position calculation means for calculating, distance calculation means for calculating the distance of the vehicle to the predetermined position, and switching means for repeating the switching operation to the predetermined position until the vehicle attitude and the vehicle position are within a predetermined tolerance value. A turning steering control device for a vehicle, comprising: a turning distance determining means for determining a distance traveled by the vehicle in the turning operation based on a vehicle attitude and a vehicle position at the time of starting the movement.