JPH0313768Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a guidance device for an automatic guided vehicle in an unmanned transportation system using a guide line as a guide path.

(Prior Art) An unmanned guided vehicle system guides an unmanned guided vehicle along a preprogrammed or set running course and route by controlling the steering of the automated guided vehicle along a guideway installed on a track or on the ground side. Among these, AC or DC current is passed through a guide wire installed on the ground side as a guideway, and the magnetic field generated by this guide wire is detected by a detection coil installed on the automatic guided vehicle. A guidance method is known in which the angle of the steered wheels of a guided vehicle is controlled in the direction of the guide line so that the vehicle can travel in a manner that follows the guide line.

As shown in Figure 2, the conventional direction detection method using a guide wire and a detection coil involves passing a low-frequency current through the guide wire R buried in the guide path, and moving the magnetic field generated by this from the center line of the carrier. Detection is performed by a pair of detection coils 1A, 1B installed at equal intervals on the left and right and in a direction perpendicular to the center line, and the induced power of both detection coils 1A, 1B is transmitted to a deviation amplifier 3 via amplifiers 2A, 2B. There is a system in which the servo motor 4 is rotated forward or reverse in the direction in which the difference disappears by comparing the sizes, and the servo motor 4 guides the conveyance vehicle along the guide line R by changing the direction of the steered wheels.

(Problem that the invention aims to solve) In the conventional guidance method, the higher the magnetic field deviation detection sensitivity, the better the followability at the curved part of the guidance line R, but even a slight lateral deviation when driving straight will change the steering angle. It becomes vibrational control. On the other hand, if the sensitivity is lowered, the followability at curved portions will deteriorate and there is a risk that the guide wire will fall off when the approach speed is high.

On the other hand, as shown in FIG. 3, there is a sensor in which the detection coils 1A and 1B are tilted so that their axes intersect on the vehicle center line ahead of the coil installation position (for example, in Japanese Patent Laid-Open No. 55 -9288).
In this case, the deviation detection sensitivity of the magnetic field is lowered to eliminate vibration when traveling straight, while the deviation at the curved portion becomes larger and its followability becomes better.

However, as shown in Fig. 4, the guide line R ₁
When entering the intersection of guide line R ₂ and guide line R ₂ , the magnetic field from guide line R ₂ is detected in addition to the magnetic field from guide line R 1, and the car is guided in a direction away from guide line R ₁ and approaches the intersection. After passing through, it will start following the original line R ₁ , resulting in unstable control and may fall off the guide line at high speeds. (Means and effects for solving the problem) The present invention includes a pair of first detection coils installed as detection coils at equal intervals left and right from the center line of the vehicle and in a direction perpendicular to the center line; A pair of second detection coils are installed on the left and right sides at equal intervals from the center line of the car, and are tilted so as to intersect on the center line of the car ahead of the installation position, and the steering wheel control circuit has a guide wire that is connected to the other guide wire. During normal driving without intersecting the guide line, the direction of the steered wheels is controlled according to the detected deviation of the second detection coil, and at the intersection of the guide lines, the direction of the steered wheels is controlled according to the detected deviation of the first detection coil. When driving, it suppresses directional vibration when traveling straight while improving followability in curved sections, and at intersections of guide lines, it eliminates the influence of magnetic fields from intersecting guide lines to perform stable follow-up steering. .

(Example) Figures 1A, B, and C show an example of the present invention,
Figure 1A is a front view of the transport vehicle, Figure 1B is a bottom view,
FIG. 1C shows the main circuit configuration diagram. In FIGS. 1A and B, the rear two wheels of the vehicle body 11 are connected to the driving wheels 12.
A and 12B, one front wheel is a steered wheel 13, drive wheels 12A and 12B are accelerated and decelerated by a drive control device (not shown), and the steered wheel 13 is directionally controlled by a servo motor 15 via a gear 14. It will be done. The control circuit 16 of this servo motor 15 is
The rotation angle of the servo motor 15 is determined according to detection signals from two pairs of detection coils 17A, 17B and 18A, 18B, which are installed symmetrically on the left and right at equal intervals from the center line of the vehicle body 11 (position of the steering wheel 13). Control.

The detection coils 17A and 17B are provided in parallel in a direction perpendicular to the center line of the vehicle body 11, and the detection coils 18A and 18B are provided at an angle so as to intersect on the center line in front of their mounting positions, as shown in the figure. In this case, the intersection position is on the axis of the detection coils 17A and 17B.

The detection signals of each detection coil are switched by changeover switches 19A, 19B as shown in FIG. 1C, and are taken into amplifiers 2A, 2B. The changeover switches 19A and 19B are interlocked, and under normal conditions, the induced voltage of the detection coils 18A and 18B is transferred to the amplifiers 2A and 19B.
2B, and the induced voltages of the detection coils 17A, 17B are introduced as inputs of the amplifiers 2A, 2B in the vicinity where the guide wire intersects with other guide wires. Switching control of the changeover switches 19A and 19B can be achieved by preparing an appropriate mark pointer and its detection means, such as having the control circuit 16 receive light from a light emitting element provided just before the intersection of the guide lines and controlling the switching. be done. The outputs of the amplifiers 2A and 2B are connected to the motor 4 by the differential amplifier 3 as in the conventional device.
It consists of a servo motor system that drives the

With this configuration, guidance control along the guide line R is performed according to the detection deviation of the detection coils 18A and 18B during normal times when the guide line R does not intersect with other guide lines, and its detection sensitivity is lowered to maintain straight travel without vibration. To improve followability at a curved part while providing good steering. In the vicinity of the intersection of the guide wires, steering is performed according to the detection deviation of the detection coils 17A and 17B, and the detection of the magnetic field from the crossed guide wires is almost eliminated, resulting in good tracking of the target guide wire R. Can be steered.

(Effects of the invention) According to the invention, a pair of detection coils in a direction perpendicular to the guide wire and a pair of inclined detection coils whose intersection is in front are switched between the normal state and the position where the guide wire crosses for detection. In order to obtain the deviation, it is possible to control with good followability while reliably preventing vibration and falling off from the guide wire.

[Brief explanation of the drawing]

FIG. 1A is a front view of an automatic guided vehicle showing an embodiment of the present invention, FIG. 1B is a bottom view thereof, FIG. 1C is a main circuit diagram showing an embodiment of the present invention, and FIGS. Third
The figure is a conventional main circuit diagram, and FIG. 4 is a magnetic field state diagram at a guide line intersection. 1A, 1B, 17A, 17B, 18A, 18B
...Detection coil, 2A, 2B...Amplifier, 3...
Differential amplifier, 4...Servo motor, 11...Vehicle body, 12A, 12B...Drive wheel, 13...Steering wheel, 14...Gear, 15...Servo motor, 16
... Control circuit, 19A, 19B ... Changeover switch, R, R ₁ , R ₂ ... Guide wire.

Claims (1)

[Scope of utility model registration request] A current is applied to a guide wire installed on the ground side, the magnetic field generated in the guide wire is detected by a detection coil installed on the automatic guided vehicle, and the control circuit controls the steering wheel of the automatic guided vehicle according to this detected amount. A guidance device for an automatic guided vehicle that controls the angle in the direction of a guide line to control the course along the guide line, wherein the detection coils are arranged at equal intervals left and right from the center line of the guided vehicle and in a direction perpendicular to the center line. A pair of first detection coils installed on the center line of the transport vehicle, and a pair of second detection coils installed on the left and right sides at equal intervals from the center line of the transport vehicle and tilted so as to intersect on the center line of the transport vehicle in front of the mounting position. , the control circuit controls the direction of the steered wheels according to the detected deviation of the second detecting coil during normal driving, and controls the direction of the steering wheel according to the detected deviation of the first detecting coil when the guiding line intersects with another guiding line. Therefore, a guidance device for an automatic guided vehicle is characterized in that the steering wheel is configured to control the direction.