JP3166418B2 - Unmanned guided vehicle steering control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an automatic guided vehicle, and more particularly to a method for controlling an automatic guided vehicle of a three-wheeled vehicle so as to reduce the amount of a vehicle body protruding inside a corner when the automatic guided vehicle is traveling along a guide line at a corner. It is something devised.

[0002]

2. Description of the Related Art An example of an automatic guided vehicle is a three-wheeled vehicle having one front wheel and two rear wheels. The vehicle travels along a guide line while detecting the guide line using a sensor provided on the bottom of the vehicle body. There is something going on.

[0003]

In the above-described automatic guided vehicle of the three-wheeled vehicle type described above, when traveling along a guide line at a corner, an inner wheel difference occurs, the vehicle body protrudes inside the corner, and ground equipment existing inside the corner is present. And the vehicle may interfere with each other.

[0004] In view of the above-mentioned prior art, the present invention relates to a three-wheeled automatic guided vehicle traveling along a corner,
An object of the present invention is to provide a method for controlling an automatic guided vehicle that reduces the amount of a vehicle body protruding inside a corner.

[0005]

The present invention for solving the above-mentioned problems has one front wheel (3) and two rear wheels (4a, 4b), and has a front wheel (3) and one rear wheel (4a). , The other rear wheel (4b) is a driven wheel, and a front sensor (5S) and a rear sensor for detecting a guide line (6) on the front side and the rear side of the bottom surface of the vehicle body (2). (5T) is a steering control method for steering an front wheel (3) and the other rear wheel (4b) when traveling on a corner by an automatic guided vehicle (1), A set point (Pi) behind the center point (Sc) of the front sensor by a distance proportional to the vehicle speed and a front sensor detection, which is a position where the front sensor (5S) detects the guide line (L). a point (S) perpendicular to and drawn from the middle point of a line connecting the (r _f), in proportion to the vehicle speed be on the vehicle body center line (L) Distance rear sensor central point (T
c), the set point (Qi) on the front side and the rear sensor (5
T), a perpendicular (r _b ) drawn from the midpoint of a line connecting the rear sensor detection point T, which is the position where the guide line (L) is detected.
And the intersection point of the turning center point (C) and the turning center point (C)
, A perpendicular (r) is drawn to the vehicle center line (L), and the angle (θ _f ) formed by the perpendicular (r) and the line connecting the turning center point (C) and the front wheel center point (P) is defined as the front wheel steering angle. The angle (θ _b ) formed between the line connecting the turning center point (C) and the rear wheel center point (Q) and the perpendicular (r) is defined as the rear wheel steering angle, and the front wheel (3)
The front wheel (3) is steered so that the steering angle of the rear wheel (4a) becomes the front wheel steering angle (θ _f ), and the rear wheel (4a) is turned so that the steering angle of the rear wheel (4a) becomes the rear wheel steering angle (θ _b ). )
It is characterized by steering.

[0006]

According to the present invention, the front wheel (3) and the rear wheel (4a) are steered such that the center of the front sensor (5S) and the center of the rear sensor (5T) are located directly above the guidance sensor (b). Perform control.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an automatic guided vehicle 1 according to an embodiment of the present invention. This automatic guided vehicle 1 has one front wheel 3
And two rear wheels 4a and 4b, the front wheel 3 performs steering and rotational driving, one rear wheel 4a performs steering and rotational driving, and the other rear wheel 4b is a driven wheel. Furthermore, body 2
On the bottom surface of the vehicle, a front sensor 5S is provided on the front side of the front wheel 3 and a rear sensor 5T is provided on the rear side of the rear wheels 4a and 4b. The sensors 5S and 5T It detects how much (distance) the center points Sc and Tc (that is, the center point in the width direction of the vehicle body 2) deviate from the position of the guide line 6. In this embodiment, the front wheel 3 and the rear wheel 4
By performing the steering of “a”, the steering control is performed so that the center points Sc and Tc of the sensors 5S and 5T are located right above the guidance line 6.

In the method of the present invention, the steering control of the front wheel 3 and the rear wheel 4a is controlled as shown in FIGS. In this case, the meaning of each point is as follows.

Sc: front sensor center point Tc: rear sensor center point S: front sensor detection point (position at which guide line 6 is detected by front sensor 5S) T: rear sensor detection point (guide line by rear sensor 5T) L: vehicle center line (line extended in the front-rear direction at the center of the vehicle width) P: front wheel center point (steering rotation axis of front wheel 3) Q: rear wheel center point (steering rotation axis of rear wheel 4a) Pi: A point on the vehicle body center line L, which is shifted rearward from the front sensor center point Sc by a distance obtained by multiplying the vehicle speed v by a preset time dt Qi: Vehicle body center line L be a point of the upper, a distance obtained by multiplying the vehicle speed v preset time dt, the point displaced from the rear sensor center point Tc in front r _f: from the midpoint of the line segment SPi, a line SPi perpendicular line was vertical for r _b: from the midpoint of the line segment TQi, line segment T perpendicular and perpendicular to the i C: pivot point r: a perpendicular from the pivot point C minus the vehicle body center line L theta _f: front wheel steering angle theta _b: rear-wheel steering angle

First, an outline of a steering control method during turning traveling will be described with reference to FIG.

When the automatic guided vehicle 1 enters a corner as shown in FIG. At this time, the center point Sc of the front sensor 5S is shifted from the detection point S at which the guide line 6 is detected, and the center point Tc of the rear sensor 5T is coincident with the detection point T at which the guide line 6 is detected. At this time, the intersection M between the vehicle body center line L and a perpendicular drawn from the turning center point C (a method for obtaining this point will be described later) to the vehicle body center line L is between the rear wheels 4a, 4b and the rear sensor 5T. The steering direction of the front wheel 3 and the steering direction of the rear wheel 4a are the same. The detailed operation will be described later with reference to FIG.

When the automatic guided vehicle 1 is in a corner as shown in FIG. At this time, the front sensor 5S
Is shifted from the center point Sc where the guide line 6 is detected, and the center point Tc of the rear sensor 5T and the detection point T where the guide line 6 is detected are also shifted. At this time, the intersection M between the vertical line drawn from the turning center point C (the method of obtaining this point will be described later) to the vehicle body center line L and the vehicle body center line L is between the front wheel 3 and the rear wheels 4a and 4b. The steering direction of the front wheels 3 and the steering direction of the rear wheels 4a are reversed. The detailed operation will be described later with reference to FIG.

When the automatic guided vehicle 1 moves away from the corner as shown in FIG. At this time, the center point Sc of the front sensor 5S and the detection point S at which the guide line 6 is detected coincide, and the center point Tc of the rear sensor 5T and the detection point T at which the guide line 6 is detected are shifted. At this time, a perpendicular line extending from the turning center point C (a method for obtaining this point will be described later) to the vehicle body center line L,
An intersection M with the vehicle center line L is located between the front wheel 3 and the front sensor 5S, and the steering direction of the front wheel 3 and the steering direction of the rear wheel 4a are the same. The detailed operation will be described later with reference to FIG.

Here, based on FIG. 3, the automatic guided vehicle 1 has a corner.
The steering control when entering the vehicle (the state shown in Fig. 2 (a))
The control method will be described. Perpendicular r from the midpoint of line segment SPi_fThe shape
And from the midpoint of the line segment TQi (where Tc = T)
Line r_bTo form a perpendicular r_f, R_bAt the intersection of the turning center point C
And From the turning center line C, the front wheel center point P and the rear wheel center
A line is formed at the point Q, and the vehicle center line L
To form a perpendicular line r (where r = r_b). And line
The angle θ between the minute PC and the perpendicular r_fThe front wheel steering angle and
And the angle θ between the line segment QC and the perpendicular r_bThe rear wheel stearin
Angle. And the steering angle of the front wheel 3 is θ_fTona
And the steering angle of the rear wheel 4a is the angle θ. _bSo that
Then, the steering operation of the front wheel 3 and the rear wheel 4b is performed.

Here, a steering control method when the automatic guided vehicle 1 is in a corner (the state of FIG. 2B) will be described with reference to FIG. Forming a perpendicular line r _b from the midpoint of the line segment TQi to form a perpendicular line r _f from the midpoint of the line segment SPi, perpendicular r
_f, and the pivot point C intersection of r _b. Lines are formed from the turning center line C to the front wheel center point P and the rear wheel center point Q, and a perpendicular line r is formed from the turning center point C to the vehicle center line L. Then the angle theta _f forming in the line PC and the perpendicular r to the front wheel steering angle, the rear wheel steering angle corners theta _b which forms with the line segment QC and the perpendicular r. Then, the steering angle of the front wheel 3 becomes θ _f and the steering angle of the rear wheel 4a becomes the angle θ _b
The steering operation of the front wheel 3 and the rear wheel 4b is performed so that

Here, based on FIG. 5, the automatic guided vehicle 1 has a corner.
Steering control when moving away from the vehicle (the state shown in FIG. 2 (c))
The method will be described. Is the midpoint of the line segment SPi (where Sc = S)
Perpendicular r_fAnd a perpendicular from the midpoint of the line segment TQi
r_bTo form a perpendicular r_f, R _bThe intersection of with the turning center point C
I do. From the turning center line C, the front wheel center point P and the rear wheel center point
A line is formed on Q, and further from the turning center point C to the vehicle center line L
A perpendicular line r is formed (where r = r_f). And line segment
Angle θ between PC and perpendicular r_fThe front wheel steering angle and
And the angle θ between the line segment QC and the perpendicular r_bThe rear wheel stearin
Angle. And the steering angle of the front wheel 3 is θ_fTona
And the steering angle of the rear wheel 4a is the angle θ._bSo that
Then, the steering operation of the front wheel 3 and the rear wheel 4b is performed.

When the vehicle travels in a corner, the steering operation is performed as described above, and the steering control is performed so that the center point Sc of the front sensor 5S and the center point Tc of the rear sensor 5T are located directly above the guide line 6. Therefore, the amount of the vehicle body 2 protruding inside the corner is reduced.

[0018]

According to the present invention, the steering control is performed so that the center point of the front sensor and the center point of the rear sensor are always directly above the guide line. Accordingly, the amount of the vehicle body protruding inside the corner while traveling on the corner is reduced. Thus, the interference with the ground equipment existing inside the corner is alleviated, and the amount (area) in which the vehicle body shifts to the inside of the corner when traveling the corner can be determined in advance from the wheelbase length, and the ground equipment is installed in this area. It can be dealt with in advance so as not to do it.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an automatic guided vehicle to which the method of the present invention is applied.

FIG. 2 is an explanatory view showing an outline of the method of the present invention.

FIG. 3 is an explanatory diagram showing a steering control method when the automatic guided vehicle enters a corner in the method of the present invention.

FIG. 4 is an explanatory view showing a steering control method when the automatic guided vehicle is in a corner in the method of the present invention.

FIG. 5 is an explanatory diagram showing a steering control method when the automatic guided vehicle moves away from a corner in the method of the present invention.

[Explanation of symbols]

Reference Signs List 1 automatic guided vehicle 2 body 3 front wheel 4a, 4b rear wheel 5S front sensor 5T rear sensor 6 guide line Sc front sensor center point Tc rear sensor center point S front sensor detection point T rear sensor detection point L body center line P from the midpoint of the front wheel center point Q rear wheel center point Pi setpoint Qi setpoint r _f line SPi, from normal r _b segment midpoint of TQi was perpendicular to the line segment SPi, relative to the line segment TQi Vertical perpendicular C Turning center point r Vertical line drawn from turning center point C to vehicle center line L θ _f Front wheel steering angle θ _b Rear wheel steering angle

Claims (1)

(57) [Claims] 1. One front wheel (3) and two rear wheels (4a,
4b), and the front wheel (3) and one rear wheel (4a) are steered.
And the other rear wheel (4b) is a driven wheel.
And guide wires (6) at the front and rear sides of the bottom of the vehicle body (2).
Sensor (5S) and rear sensor (5T) for detecting
When the automatic guided vehicle (1) equipped with
To steer the front wheel (3) and the other rear wheel (4b)
The vehicle is located on the center line (L) of the vehicle body and is forward by a distance proportional to the vehicle speed.
Set point (Pi) behind the central sensor (Sc)
And the guidance line (L) was detected by the front sensor (5S)
Is the middle point of the line connecting the front sensor detection point (S)
Vertical line (r _f), And on the vehicle center line (L), after a distance proportional to the vehicle speed
Set point (Qi) on the front side of the center sensor (Tc) of the sensor
And the guide wire (L) was detected by the rear sensor (5T).
From the middle point of the line connecting the rear sensor detection point T
Vertical line (r_b) And the turning center point (C), and a perpendicular (r) is drawn from the turning center point (C) to the vehicle center line (L).
Line connecting the turning center point (C) and the front wheel center point (P)
Angle (θ) between the_f) The front wheel steering angle
And a line connecting the turning center point (C) and the rear wheel center point (Q).
Angle (θ) between the_b) The rear wheel steering angle
And the steering angle of the front wheel (3) is the front wheel steering angle (θ_f) And
The front wheel (3) is steered and the rear wheel (4a)
The steering angle of the rear wheel steering angle (θ_bAfter)
An automatic guided vehicle characterized by steering a wheel (4a).
Steering control method.