JP2512951B2 - Automatic guided vehicle guidance device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used for a guide device for an automated guided vehicle that travels using a metal and a magnetic material as a marker. Automated guided vehicles are used to transport materials and products in factories.

〔Overview〕

INDUSTRIAL APPLICABILITY According to the present invention, in an unmanned guided vehicle guidance device, the central axis of the exciting coil that generates an alternating magnetic field and produces an eddy current in the metal marker is substantially orthogonal to each other Phase detection output of the phase detection coil that detects the phase of the AC magnetic field generated by the excitation coil by detecting the magnetic field due to the eddy current of the metal marker when the automated guided vehicle is displaced from the metal marker by the generated magnetic field detection coil. By synchronously detecting with and outputting a signal corresponding to the left-right deviation, the deviation from the metal sign can be detected with one magnetic field detection coil, and the width in the width direction of the vehicle is reduced. It is a thing.

[Conventional technology]

FIG. 6 is a plan view of a conventional guided vehicle guided apparatus. In the first, 8 is an unmanned guided vehicle guiding device, 9 is a metal proximity sensor (coil), 10 is an unmanned guided vehicle, and 11 is a metal sign indicating the traveling path of the unmanned guided vehicle 10.

Conventionally, an unmanned guided vehicle guiding apparatus has been used in which two metal proximity sensors 9 are installed side by side in the vehicle width direction as shown in FIG. If the metal proximity sensors 9 are arranged side by side in the vehicle width direction of the vehicle at intervals slightly smaller than the width of the metal marker 11, two metal proximity sensors are used when the vehicle is traveling along the center of the metal marker 11. 9 is a metal label
11 is detected, but when the vehicle approaches to one side, one of the two metal proximity sensors 9 detects the metal marker 11, but the other one is not detected.
10 determines the steering direction according to the signal.

The metal proximity sensor 9 uses a coil, and detects the metal by utilizing the fact that the inductance of the coil changes (decreases) when approaching the metal.

[Problems to be solved by the invention]

However, in such an unmanned guided vehicle guiding apparatus of the conventional example, since the two metal proximity sensors 9 must be installed at the same distance as the width of the metal marker 11, the length in the vehicle width direction is the metal marker. It cannot be made smaller than the width of the body 11, and the detection distance of the metal proximity sensor 9 utilizing the inductance change becomes shorter as the metal becomes smaller, so that it is difficult to make the width of the metal band of the metal marker 11 small. Therefore, the automatic guided vehicle guiding device 8 has a drawback that it cannot be downsized.

The present invention solves the above-mentioned drawbacks, and an object of the present invention is to provide an unmanned guided vehicle guiding apparatus capable of reducing the length of the unmanned guided vehicle in the vehicle width direction.

[Means for solving problems]

The present invention, in an unmanned guided vehicle guiding apparatus that detects a metal marker indicating a traveling path and guides an automatic guided vehicle along the metal marker, generates an AC magnetic field to generate an eddy current in the metal marker. An exciting coil, an oscillator for exciting the exciting coil, and a central axis of the exciting coil located near the exciting coil and orthogonal to the central axis of the exciting coil and symmetrical with respect to the central axis of the exciting coil. A magnetic field detection coil for detecting a magnetic field generated by an eddy current of the marker when the center axis thereof is arranged in the left-right direction with respect to the traveling direction of the automatic guided vehicle and the automatic guided vehicle is displaced from the metal marker. And a phase detection coil located near the excitation coil for detecting the phase of the alternating magnetic field generated by the excitation coil, and a magnetic field detection output of the magnetic field detection coil for detecting the phase of the phase detection coil. Synchronous detection with known output, characterized in that a synchronous detection circuit for outputting a signal corresponding to the deviation from the metal label.

[Action]

An alternating magnetic field is generated by the excitation coil to generate an eddy current in the metal marker. The magnetic field detection coil detects the magnetic field generated by the eddy current of the metal marker when the automatic guided vehicle is displaced from the metal marker. The phase detection coil detects the phase of the alternating magnetic field generated by the excitation coil and outputs the phase detection output.
The synchronous detection circuit synchronously detects the magnetic field detection output with the phase detection output and outputs a signal corresponding to the deviation from the metal marker. With the above operation, the deviation from the metal marker can be detected by one magnetic field detection coil, and the length of the vehicle in the vehicle width direction can be reduced.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an automated guided vehicle guiding apparatus according to an embodiment of the present invention. In FIG. 1, the automatic guided vehicle guiding device is
Excitation coil 1 for generating an alternating magnetic field to generate an eddy current in a metal marker and an oscillator 2 connected to the excitation coil 1
A phase detection coil 3 for detecting the phase of the magnetic field generated by the excitation coil 1 and an amplifier circuit 4 for amplifying the phase detection output of the phase detection coil 3; and the central axis thereof is substantially orthogonal to the central axis of the excitation coil 1. A magnetic field detection coil 5 and a magnetic field detection coil 5 that are installed substantially symmetrically with respect to the central axis of the excitation coil 1 and that detect the magnetic field generated by the eddy current of the metal marker when the automatic guided vehicle is displaced from the metal marker. The magnetic field detection output of the amplifier circuit 6 and the output of the amplifier circuit 6 are amplified circuit 4
And a synchronous detection circuit 7 that outputs a signal corresponding to a left-right shift.

The operation of the unmanned guided vehicle guiding apparatus having such a configuration will be described. FIG. 2 is a layout drawing of each coil of the automatic guided vehicle guiding apparatus of the present invention. FIG. 3 is a diagram showing the relationship between the magnetic field detection coil and the magnetic field lines of the excitation coil when the automatic guided vehicle guide apparatus of the present invention is not displaced from the metal marker. Fourth
The figure is a diagram showing the relationship between the magnetic field detection coil and magnetic field lines due to eddy currents when the automatic guided vehicle guiding apparatus of the present invention is displaced to the left from the metal identifying body when viewed from the traveling direction of FIG. Fifth
The figure is a diagram showing the relationship between the detection output of the synchronous detection circuit of the automatic guided vehicle guiding apparatus of the present invention and the deviation from the metal marker.
In FIG. 1, the magnetic field detection output of the magnetic field detection coil 5 passes through the amplifier circuit 6 and is detected by the synchronous detection circuit 7 using the phase detection output of the phase detection coil 3 as a synchronization signal. As shown in FIG. 2, the magnetic field detection coil 5 is installed symmetrically in the direction in which the excitation coil 1 and the central axis of the coil are orthogonal to each other. The magnetic field lines from the excitation coil 1 are applied to the magnetic field detection coil 5 installed as shown in FIG. Is zero.

Consider a case where the automatic guided vehicle guidance device is brought close to the metal marker 11. An eddy current is generated on the metal surface by the magnetic field of the excitation coil 1, and a magnetic field is generated by the eddy current. The state is shown in FIG. 4, 13 is the magnetic field line by the excitation coil 1,
The broken line 14 indicates the magnetic field line due to the eddy current generated in the metal marker 11. As described above, the magnetic force lines 13 do not induce a voltage in the magnetic field detection coil 5, but the magnetic force lines 14 penetrate the magnetic field detection coil 5 from left to right, so that an induced electromotive force is generated in the magnetic field detection coil 5. When the metal marker 11 comes to the right side of the excitation coil 1 and the magnetic field detection coil 5, the magnetic field lines penetrate from the right to the left in the magnetic field detection coil 5 contrary to FIG. The magnetic field detection coil 5 depends on whether the metal marker 11 is on the left or right.
The phase of the induced electromotive force of is inverted. If the coil of the phase detection coil 3 is positioned on the center line in the traveling direction of the guiding device as shown in FIG. 2, the phase is obviously unchanged regardless of whether the metal marker 11 is on the left or right. As shown in FIG. 6, by synchronously detecting the detection output of the magnetic field detection coil 5 using this phase detection output as a synchronization signal, the output signal is inverted between positive and negative depending on whether the metal marker 11 is on the left or right side. To do. FIG. 5 shows the detection output characteristics when the automatic guided vehicle guiding device is moved left and right with respect to the metal marker 11 while keeping the same height.

〔The invention's effect〕

As described above, the present invention has an excellent effect that one magnetic field detection coil can identify whether the metal marker is on the left or right, and the length in the vehicle width direction of the vehicle can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of an automated guided vehicle guiding apparatus according to an embodiment of the present invention. FIG. 2 is a layout drawing of each coil of the automatic guided vehicle guiding apparatus of the present invention. FIG. 3 is a diagram showing a relationship between a magnetic field detection coil and a magnetic field due to an eddy current when the automatic guided vehicle guide apparatus of the present invention is not displaced from a metal marker. FIG. 4 is a diagram showing a relationship between a magnetic field detection coil and a magnetic field due to an eddy current when the automatic guided vehicle guide apparatus of the present invention is displaced from a metal marker. FIG. 5 is a diagram showing the relationship between the detection output of the synchronous detection circuit of the automatic guided vehicle apparatus of the present invention and the deviation from the metal marker. FIG. 6 is a plan view of a conventional guided vehicle guided apparatus. 1 ... Excitation coil, 2 ... Oscillator, 3 ... Phase detection coil,
4, 6 ... Amplification circuit, 5 ... Magnetic field detection coil, 7 ... Synchronous detection circuit, 8 ... Automated guided vehicle guidance device, 9 ... Metal proximity sensor,
10 ... Automated guided vehicle, 11 ... Metallic sign.

Claims (1)

(57) [Claims] 1. An unmanned guided vehicle guiding apparatus for detecting a metal marker indicating a traveling path and guiding a guided vehicle along the metal marker, the apparatus being arranged so as to be orthogonal to the metal marker and having an alternating magnetic field. And an excitation coil for generating an eddy current in the metal marker, an oscillator for exciting the excitation coil, and a central axis located near the excitation coil and orthogonal to the central axis of the excitation coil. The central axis of the excitation coil is arranged in the left-right direction with respect to the traveling direction of the automatic guided vehicle so as to be symmetrical with respect to the central axis of the excitation coil, and the marker is displaced when the automatic guided vehicle is displaced from the metal marker. Magnetic field detection coil for detecting the magnetic field generated by the eddy current of the above, a phase detection coil located near the excitation coil for detecting the phase of the alternating magnetic field generated by the excitation coil, and the magnetic field detection Yl AGV guidance system which is characterized in that a synchronous detection circuit for outputting a signal corresponding to the deviation from magnetic field detecting outputs synchronous detection the metal label with the phase detection output of the phase detection coil.