JPH04198712A - Position detecting method for magnetic propulsion running body - Google Patents

Abstract

PURPOSE:To detect a position over a long distance with a simple system by transmitting the coherent light on a light transmission line crossing the magnetic field from a magnetic propulsion running body, and receiving the light-modulated signal with the rotated polarization plane by the magnetic field. CONSTITUTION:The magnetic field from a magnetic propulsion running body 1 on a running path 2 is applied to a light transmission line 3 installed on the running path 2. When the advance direction of the coherent light in the transmission line 3 and the direction of the magnetic field coincide, the polarization plane of the light is rotated in the positive or negative direction in proportion to the magnitude of the magnetic field by the Faraday effect, and the polarization plane is changed by the running of the running body 1. When the light is received by a light receiver 5 via a polarizer 4, the light-modulated signal modulated by since waves is obtained. Then number of speaks of this signal corresponds to the number of the transmission lines 3, when the number of th transmission lines 3 is counted, the position of the running body 1 can be detected. The position can be detected over a long distance with a simple system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting the position of a magnetically propulsion vehicle that generates a high magnetic field, such as a linear motor car. BACKGROUND OF THE INVENTION Conventionally, crossed guide lines have been used to detect the position of a magnetically propelled vehicle that generates a high magnetic field. [Problems to be Solved by the Invention] The longer the cross-guide wire is, the greater the resistance, so the position detection distance with a single cross-guide wire is as short as several kilometers. It would be desirable to extend the possible distance, but it is technically impossible under the current conditions. In addition, because the cable shape of the crossing guide wire is wide, it is susceptible to wind pressure due to the running of magnetic propulsion vehicles traveling at high speed due to its installation position, and the wind pressure causes the cable to dance and become fatigued, resulting in long-term reliability. This is a contributing factor to the decline in sexuality. OBJECTS OF THE INVENTION An object of the present invention is to provide a method for detecting the position of a magnetically propulsion vehicle that is capable of long-distance position detection, is less susceptible to wind pressure, has high reliability, and is inexpensive. [Means for Solving the Problems] The method for detecting the position of a magnetically-propelled traveling body according to the present invention is to detect the position of a magnetically-propelled traveling body 1, such as a linear motor car, along a running path 2 of the magnetically-propelled traveling body 1, such as a linear motor car, as shown in FIG. A magnetic propulsion vehicle l transmits coherent light to a single-mode optical transmission line 3 installed so as to have a component that intersects the magnetic field generated from the magnetic field I, and passes the polarization plane of the coherent light over the running path 2. The coherent light is rotated by the Faraday effect of the magnetic field generated by the light beam and becomes the light modulation signal A shown in FIG. 3, and this light modulation signal A is received through the polarizer 4 to detect the position of the traveling body l. This is what I did. [Operation] In the method for detecting the position of a magnetically propulsion vehicle according to the present invention, FIG.
A magnetic field is also generated by the magnetic propulsion vehicle l passing on the traveling path 2 of , b, which is applied to the optical transmission line 3 installed on the traveling path 2, and changes the traveling direction of the light within the optical transmission line 3. When the directions of the magnetic fields match, the plane of polarization of the light rotates in proportion to the magnitude of the magnetic field due to the Faraday effect as shown in Figure 2. When a magnetic field (in the direction opposite to the traveling direction of When traveling, a magnetic field ■ in the same direction as the traveling direction of the light is applied to the optical transmission line 3,
The plane of polarization rotates in the negative direction (to the left in FIG. 2) as shown in FIG. Thereafter, the plane of polarization changes in the same manner as the magnetic propulsion vehicle 10 travels. When this is received by the light receiver 5 through the polarizer 4 shown in FIG. 1a, it becomes an optical modulation signal A to which sinusoidal modulation has been added as shown in FIG. Since the number of peaks of the modulation signal A corresponds to the number of optical transmission lines 3 that are present perpendicular to the traveling direction of the magnetically propelled vehicle 1, the position of the vehicle I can be detected by counting this number. [Embodiment] Among the embodiments of the present invention, those shown in FIGS. 1a and 1b use a single-mode optical fiber as the optical transmission line 3, which is meandered in advance at a uniform pitch on a carpet-like base material 6. The base material 6 is connected to a linear motor car (magnetic propulsion vehicle) so that the optical transmission path 3 is perpendicular to the traveling direction of the vehicle L.
It is installed on the running path 2 of 1. Among the embodiments of the present invention, the one in FIG. 4 uses two single mode optical fibers 3a and 3b as the optical transmission line 3,
The two optical fibers 3a and 3b are laid on the running path 2 of the magnetic propulsion vehicle 1 with different meandering pitches, and the optical fibers 3a and 3b are arranged at right angles to the traveling direction of the magnetic propulsion vehicle l. It is. In this case, the pitch of the optical fibers 3a with a wide meandering width is 5 to 10 times the pitch of the optical fibers 3b with a narrow meandering width. In this way, the rough position of the traveling body l can be detected using the optical fibers 3a with a large pitch, and the detailed position of the traveling body l can be detected using the optical fibers 3b with a small pitch. [Effects of the Invention] The method for detecting the position of a magnetically propelled vehicle according to the present invention has the following effects. a. Since the position of the magnetic propulsion vehicle can be detected using an optical transmission line such as an optical fiber, the position can be detected over a long distance with a single optical transmission line, compared to the case where a cross-guide line is used. . This makes the system simpler and the cost lower than that of cross-guiding wires. b. Since it uses an optical transmission line, it is not affected by external noise. Since coherent light is transmitted to the C0 optical transmission path and a magnetic field generated from the magnetic propulsion vehicle l is applied thereto, the detection device is also simple. d. Iia Since an optical transmission line that is thinner than the cross guide line is laid along the running path of the magnetic propulsion vehicle, it is less susceptible to wind pressure generated by the travel of the magnetic propulsion vehicle, making it difficult for the optical transmission line to dance due to wind pressure. . For this reason, long-term reliability is improved compared to when using crossed guiding wires.

[Brief explanation of the drawing]

FIG. 1a is an explanatory plan view showing the relationship between the optical transmission direction and the direction of the magnetic field in the present invention, the same figure is a front view thereof, FIG. 2 is an explanatory view of the rotation direction of the polarization plane in the present invention, FIG. 4 is an explanatory diagram of an optical modulation signal, and FIG. 4 is an explanatory diagram showing the other side of the wiring state of the optical transmission line of the present invention. 1 is a magnetic propulsion vehicle 2 is a running path 3 is an optical transmission line 4 is a polarizer Applicant: Railway Technical Research Institute Figure 2 Figure 3 Magnetic flux t-1゜lji+, -' Time axis

Claims (1)

[Claims] Coherent light is transmitted along a running path 2 of a magnetically propulsion vehicle 1 such as a linear motor car to a single-mode optical transmission line 3 installed so as to have a component that intersects the magnetic field generated from the vehicle 1. , the plane of polarization of the coherent light is rotated by the Faraday effect of the magnetic field generated from the magnetic propulsion vehicle 1 passing over the traveling path 2, and the coherent light is made into an optical modulation signal A, and this optical modulation signal A is polarized. Child 4
1. A method for detecting the position of a magnetically propulsion vehicle, characterized in that the position of the vehicle 1 is detected by receiving data through a magnetically propelled vehicle.