Sensor-integrated electromagnetic induction cable and electromagnetic induction system

Abstract

To provide a sensor integrated electromagnetic induction cable obtained by adding moving body detection capability on a road to an electromagnetic induction cable used for an automatic drive system.SOLUTION: A sensor-integrated electromagnetic induction cable includes: a long body; one or more optical fibers; one or more electromagnetic induction wires; and one or more tension members. The optical fiber, the electromagnetic induction wires, and the tension members are positioned inside the body apart from each other, and extend in a longitudinal direction of the body. It is preferable that two or more tension members are provided, and the optical fiber and the electromagnetic induction wire are positioned between an arbitrary tension member and any other arbitrary tension member.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sensor-integrated electromagnetic induction cable and an electromagnetic induction system. [Background technology]

[0002] In recent years, systems using optical fiber-based distributed vibration / acoustic sensing (DAS) devices have been put into practical use, such as road monitoring using existing communication optical fiber buried along roads, and site boundary or border monitoring systems using newly buried optical fiber. As an example of a newly installed optical fiber, an optical fiber cable has been proposed in which an outer jacket, multiple tension members, a tight core for strain measurement, and a loose core for temperature measurement are arranged in the same line (Patent Document 1).

[0003] In areas where it is difficult to continue using public transportation, the introduction of self-driving cars is being considered as a way to ensure mobility. Self-driving technology includes systems that rely solely on on-board sensors and systems that also use electromagnetic induction wires buried in the road. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-189566 Summary of the Invention [Problem to be solved by the invention]

[0005] In an autonomous driving system using electromagnetic induction lines, route information is obtained from the electromagnetic induction lines and obstacle detection is performed using various on-board sensors. Obstacle detection using on-board sensors has problems such as performance degradation due to weather conditions and limited detection distance due to unseen curves, etc. The present invention has been made in view of the above circumstances, and provides an electromagnetic induction cable with an integrated sensor, which is an electromagnetic induction cable that is equipped with the ability to detect moving objects on a road. [Means for solving the problem]

[0006] The present invention has the following aspects. <1> The optical fiber has an elongated body, one or more optical fibers, and one or more electromagnetic induction wires. The optical fiber and the electromagnetic induction wire are located inside the main body, spaced apart from each other, and extend in the longitudinal direction of the main body. <2> Furthermore, it has one or more tension members, the tension member is located inside the main body, spaced apart from the optical fiber and the electromagnetic induction line, and extends in the longitudinal direction of the main body. <1> The sensor-integrated electromagnetic induction cable described in <3> The tension member has two or more members, the optical fiber and the electromagnetic induction wire are located between any one of the tension members and any other one of the tension members; <2> The sensor-integrated electromagnetic induction cable described in <4> the arbitrary tension member, the other arbitrary tension member, and the optical fiber and the electromagnetic induction line positioned between these tension members are aligned on a straight line in a cross-sectional view; <3> The sensor-integrated electromagnetic induction cable described in <5> For electromagnetic induction systems, <1> ~ <4> 1. The sensor-integrated electromagnetic induction cable according to claim 1,

[0007] <6> <1> ~ <4> 10. An electromagnetic induction system having the sensor-integrated electromagnetic induction cable according to any one of claims 1 to 9. [Effects of the Invention]

[0008] According to the sensor-integrated electromagnetic induction cable of the present invention, the capability of detecting moving objects on the road can be added to the electromagnetic induction cable. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view of a sensor-integrated electromagnetic induction cable according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram of an electromagnetic guidance system according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0010] In this specification and claims, the use of "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. The drawings are schematic diagrams for easily explaining the configuration, and the dimensional ratios of each component may differ from the actual ones.

[0011] (Electromagnetic induction cable with integrated sensor) The sensor-integrated electromagnetic induction cable of the present invention includes a long main body, one or more optical fibers, one or more electromagnetic induction wires, and one or more tension members. The sensor-integrated electromagnetic induction cable of the present invention will be described below with reference to one embodiment.

[0012] FIG. 1 is a cross-sectional view (cross-section perpendicular to the longitudinal direction) of a sensor-integrated electromagnetic induction cable 1. The sensor-integrated electromagnetic induction cable 1 of FIG. 1 has a long main body 10, two tension members 20, one optical fiber 30, and one electromagnetic induction wire 40. The two tension members 20, one optical fiber 30, and one electromagnetic induction wire 40 are located inside the main body 10 and extend in the longitudinal direction of the main body 10. The two tension members 20, one optical fiber 30, and one electromagnetic induction wire 40 are spaced apart from each other. The main body 10 is joined to two tension members 20, one optical fiber 30, and one electromagnetic induction wire 40. This allows the optical fiber 30 to more accurately detect vibrations transmitted to the sensor-integrated electromagnetic induction cable 1.

[0013] The cross section of the sensor-integrated electromagnetic induction cable 1 is a rectangle with the width direction as the long side and the thickness direction as the short side. In a cross-sectional view, the two tension members 20 are located on both sides in the width direction. In a cross-sectional view, the optical fiber 30 and the electromagnetic guide wire 40 are located between the two tension members 20. In this embodiment, the two tension members 20, the optical fiber 30, and the electromagnetic guide line 40 are aligned in a straight line. Note that "aligned in a straight line" means that when an imaginary line P is drawn in the width direction in a cross-sectional view, the tension members 20, the optical fiber 30, and the electromagnetic guide line 40 are positioned on the imaginary line P.

[0014] The length of the sensor-integrated electromagnetic induction cable 1 can be determined appropriately depending on the installation location. The width W1 of the sensor-integrated electromagnetic induction cable 1 (the width of the main body 10) is, for example, 4 mm to 30 mm. The thickness T1 of the sensor-integrated electromagnetic induction cable 1 (thickness of the main body 10) is, for example, 1.5 mm to 15 mm.

[0015] <Main body> The main body 10 is preferably flexible. Materials for the main body 10 include resin, ceramics, etc. Among these, resin is preferred as the material for the main body 10 because of its excellent flexibility. The resin constituting the main body 10 is polyolefin, elastomer, rubber, polyamide, polyester, etc. The polyolefin is polyethylene, polypropylene, etc. The elastomer is an olefin-based elastomer, a styrene-based elastomer, a polyester-based elastomer, etc. Among these, polyolefins and elastomers are preferred as the resins constituting the main body 10, as they are easy to mold and have excellent strength, polyolefins are more preferred, and polyethylene is even more preferred. When the body 10 is made of resin, the body 10 may contain optional components such as a colorant, an ultraviolet absorber, and talc. Furthermore, when the main body 10 is made of resin, the main body 10 may be a foamed body or a non-foamed body.

[0016] <Tension member> The tension member 20 is a so-called reinforcing member and extends in the longitudinal direction of the sensor-integrated electromagnetic induction cable 1. The tension member 20 may be made of any material that can function as a reinforcing member, such as a metal wire, a resin wire, or a glass wire. An example of a metal wire is a copper wire. An example of a resin wire is an aramid fiber reinforced plastic (AFRP) wire or a glass fiber reinforced plastic (GFRP) wire. Since metal wires such as steel wires may be subject to induction from power lines, etc., a resin wire is preferred for the tension member 20.

[0017] The outer diameter R20 of the tension member 20 is preferably 125 μm to 5000 μm, more preferably 250 μm to 2000 μm, and even more preferably 900 μm to 1500 μm. If the outer diameter R20 is equal to or greater than the above-mentioned lower limit, breakage of the sensor-integrated electromagnetic guide cable 1 and disconnection of the optical fiber 30 and the electromagnetic guide wire 40 can be more reliably prevented. If the outer diameter R20 is equal to or less than the above-mentioned upper limit, excessive increase in thickness T1 of the sensor-integrated electromagnetic guide cable 1 can be prevented. If the cross section of the tension member 20 is not a perfect circle, the outer diameter R20 is the diameter of the circumscribed circle of the cross section.

[0018] <Optical fiber> The optical fiber 30 extends in the longitudinal direction of the sensor-integrated electromagnetic induction cable 1. The optical fiber 30 may be a bare fiber, a fiber strand, or a fiber core. A bare fiber is a fiber that consists of a core and at least one cladding layer surrounding the core, and is made up of only glass. The fiber strand is a bare fiber whose outer periphery is coated with an ultraviolet curable resin. The optical fiber is a fiber in which the outer periphery of a bare fiber is coated with a thermoplastic resin (a fiber having a coating resin layer of a thermoplastic resin).

[0019] The optical fiber 30 can be, for example, for measuring dynamic strain or temperature. The optical fiber 30 for measuring dynamic strain is preferably a single-mode optical fiber. The optical fiber 30 for measuring temperature is preferably a multi-mode optical fiber.

[0020] When the sensor-integrated electromagnetic induction cable 1 has two or more optical fibers 30, the types of the two or more optical fibers 30 may be the same or different from each other. The sensor-integrated electromagnetic induction cable 1 may have a tight core wire for measuring dynamic strain and another optical fiber (for example, an optical fiber for measuring temperature).

[0021] The outer diameter R30 of the optical fiber 30 is preferably 125 μm to 2000 μm, and more preferably 150 μm to 1000 μm. When the outer diameter R30 is equal to or greater than the above lower limit, the optical fiber is less likely to break when a load is applied, which improves productivity and durability. When the outer diameter R30 is equal to or less than the above upper limit, the balance between durability and ease of handling is improved.

[0022] The core may be made of, for example, quartz glass. The material of the cladding is the same as that of the core. The core material and the clad material may be the same or different.

[0023] When the optical fiber 30 is a fiber core, examples of the resin that constitutes the coating resin layer include polyolefin, polyester, polyamide, polyimide, and fluororesin.

[0024] <Electromagnetic induction wire> The electromagnetic induction wire 40 extends in the longitudinal direction of the sensor-integrated electromagnetic induction cable 1. The electromagnetic induction wire 40 may be any wire that enables travel control by electromagnetic induction using a current of a predetermined frequency (induced current). The electromagnetic induction wire 40 may be, for example, a conductor made of a good electrical conductor such as a twisted copper wire, copper wire, aluminum wire, or an alloy wire of these, or a twisted wire thereof.

[0025] The cross-sectional area of ​​the electromagnetic induction wire 40 is, for example, 0.5 mm 2 ~5.5mm 2 The outer diameter R40 of the electromagnetic induction wire 40 is, for example, 0.8 mm to 2.7 mm. If the cross section of the electromagnetic induction wire 40 is not a perfect circle, the outer diameter R40 is the diameter of the circumscribed circle of the cross section.

[0026] <Manufacturing method> An example of a method for manufacturing the sensor-integrated electromagnetic induction cable 1 will be described below, taking as an example a case where the main body 10 is made of resin. The resin that constitutes the main body 10, the tension member 20, the optical fiber 30, and the electromagnetic induction wire 40 are supplied to the mold of an extrusion molding machine, and the molded body in which the tension member 20, the optical fiber 30, and the electromagnetic induction wire 40 are positioned within the main body 10 is taken up using a take-up machine installed downstream of the mold, thereby obtaining a sensor-integrated electromagnetic induction cable 1.

[0027] (Electromagnetic Induction System) The electromagnetic guidance system of the present invention includes one or more sensor-integrated electromagnetic guidance cables of the present invention. That is, in this embodiment, the sensor-integrated electromagnetic guidance cables are used for the electromagnetic guidance system. An example of the vibration measuring device is a distributed vibration / acoustic sensing (DAS) device. The electromagnetic induction system 110 in FIG. 2 is an example having one sensor-integrated electromagnetic induction cable 1, a vibration measuring device 100, and an electromagnetic induction signal generating device 200.

[0028] The sensor-integrated electromagnetic induction cable 1 is connected to a vibration measuring device 100 via an optical fiber 30. The sensor-integrated electromagnetic induction cable 1 is connected to an electromagnetic induction signal generator 200 via an electromagnetic induction wire 40. That is, in this embodiment, the sensor-integrated electromagnetic induction cable 1 is used for both the vibration measuring device and the electromagnetic induction signal generator. The vibration measuring device 100 includes a detection unit 101, a data processing unit 102, and a data output unit 103. To the detection unit 101, an optical fiber 30 is connected. The data processing unit 102 comprises a processor configured to process the signals measured by the detection unit 101 . The data processing unit 102 may be located at the same location as the detection unit 101 or may be located at a location separate from the detection unit 101 . The data output unit 103 has an interface to a communication network that transmits the output information of the data processing unit 102 to an external device. The data output unit 103 may be located in the same place as the data processing unit 102, or may be located at a location separate from the data processing unit 102.

[0029] During operation of the vibration measuring device 100, the detecting unit 101 repeatedly emits light pulses into the optical fiber 30. In the optical fiber 30, a portion of the repeatedly emitted light pulses returns to the detecting unit 101 due to backscattering of light. The detection unit 101 detects the returned backscattered light and outputs measurement signals representing disturbances such as temperature, vibration, and strain acting on the optical fiber 30 to the data processing unit 102 as measurement signals DT from multiple individual sensing portions distributed along the length of the optical fiber 30.

[0030] The data processing unit 102 estimates information about the moving object, such as the position and speed of the moving object, and road conditions, based on the measurement signals DT distributed along the optical fiber 30 . The data processing unit 102 may temporarily store the measurement signal DT.

[0031] The data output unit 103 efficiently transmits the information DM about the moving object estimated by the data processing unit 102 to the road-vehicle cooperative system via a network.

[0032] (How to use) As an example of how the electromagnetic guidance system 110 is used, an example of using it as a road monitoring system in an automatic driving system will be described. The sensor-integrated electromagnetic induction cable 1 is buried under the road surface. When a moving object passes over the road on which the sensor-integrated electromagnetic induction cable 1 is buried, when a heavy object falls onto the road, or when vibrations occur due to a landslide, earthquake, or the like, these vibrations propagate through the sensor-integrated electromagnetic induction cable 1 and are then transmitted to the optical fiber 30 within the sensor-integrated electromagnetic induction cable 1. When vibrations are transmitted to the optical fiber 30, they are detected by the detection unit 101 as dynamic distortion at the vibrating point of the optical fiber 30. Based on these inputs, the data processing unit 102 estimates information about the moving object, such as its position and speed, as well as road conditions. The output information of the data processing unit 102 is transmitted to an external road-vehicle cooperation system via the data output unit 103. In-vehicle sensors may lose their ability to detect obstacles in bad weather (for example, thick fog or snowfall) or around curves with poor visibility. However, the sensor-integrated electromagnetic induction cable 1 directly detects vibrations that occur on the road surface, making it possible to grasp road conditions more accurately even in bad weather or around curves with poor visibility. This makes it possible to grasp road conditions at distances that cannot be seen with the naked eye from the location of the moving object.

[0033] As described above, the sensor-integrated electromagnetic induction cable of the present invention makes it possible to continuously and sensitively detect vibrations caused by moving objects and the like over the entire length of the road in which it is buried. In addition, based on vibration information detected by the sensor-integrated electromagnetic induction cable, information about the moving object, such as its position and speed, and road information are generated. The generated information on the moving object, etc. is provided to the road-vehicle cooperative safe driving support device.

[0034] (Other embodiments) Although the above-described embodiment has one optical fiber, the present invention is not limited to this, and the main body may have two or more optical fibers.

[0035] Although the above-described embodiment has one electromagnetic induction wire, the present invention is not limited to this, and the main body may have two or more electromagnetic induction wires.

[0036] In the above embodiment, there are two tension members, but the present invention is not limited to this, and the number of tension members in the main body may be one, or three or more. The sensor-integrated electromagnetic induction cable of the present invention does not need to have a tension member, but if the main body is flexible or stretchable, it is preferable that it has a tension member.

[0037] In the above-described embodiment, the optical fiber and the electromagnetic induction line are located between the two tension members, but the present invention is not limited to this, and one or both of the optical fiber and the electromagnetic induction line may not be located between the tension members. [Explanation of symbols]

[0038] 1. Sensor integrated electromagnetic induction cable 10 Main Unit 20 tension members 30 Optical Fiber 40 Electromagnetic Induction Lines 100 Vibration measuring device 101 Detector 102 Data processing section 103 Data output section 110 Electromagnetic Induction System 200 Electromagnetic induction signal generator

Claims

1. The optical fiber has an elongated body, one or more optical fibers, and one or more electromagnetic induction wires; The optical fiber and the electromagnetic induction wire are located inside the main body, spaced apart from each other, and extend in the longitudinal direction of the main body.

2. Further, it has one or more tension members, 2. The sensor-integrated electromagnetic induction cable according to claim 1, wherein the tension member is located inside the main body, spaced apart from the optical fiber and the electromagnetic induction line, and extends in the longitudinal direction of the main body.

3. The tension member has two or more members, 3. The sensor-integrated electromagnetic induction cable according to claim 2, wherein the optical fiber and the electromagnetic induction line are located between any one of the tension members and another one of the tension members.

4. 4. The sensor-integrated electromagnetic induction cable according to claim 3, wherein the arbitrary tension member, the other arbitrary tension member, and the optical fiber and the electromagnetic induction line located between these tension members are aligned in a straight line in a cross-sectional view.

5. The sensor-integrated electromagnetic induction cable according to any one of claims 1 to 4, which is used for an electromagnetic induction system.

6. An electromagnetic induction system comprising the sensor-integrated electromagnetic induction cable according to any one of claims 1 to 4.

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