JP2017015473A - Speed measurement device, its attachment method, and vehicle attached with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speed measurement device, speed control device of the speed measurement device, attachment method of the speed control device, and vehicle attached with the speed control device that reduce a speed measurement error due to an electromagnetic wave reflected in a reflection angle direction on a travelling road surface.SOLUTION: On a floor surface of a transport vehicle upon which an electromagnetic wave radiated from an antenna reflected in a reflection angle direction from a travelling road surface is incident, a planar reflection control member is arranged, and in addition to the arrangement, further, an angle of incidence θ in an incident direction between the incident direction of the electromagnetic wave radiated from the antenna and the travelling road surface is set to an angle range of 20°-40°. The electromagnetic wave is returned through the almost same route due to the planar reflection control member, and thereby the electromagnetic wave is not reflected in an unexpected direction to enable reduction in a measurement error. Further, the angle of incidence in the incident direction of the electromagnetic wave is set to 20°-40°, which in turn a speed can be measured within a prescribed error range even when a plane part of the reflection control member and the travelling road surface are not parallel with each other.SELECTED DRAWING: Figure 10

Description

  The present invention radiates millimeter-wave band or microwave band electromagnetic wave toward the traveling road surface, measures the frequency change of the reflected wave to calculate the speed of the transportation vehicle, its mounting method, and It relates to the vehicle to which it is attached.

  In general, as a method for detecting a ground speed in a transportation vehicle such as an automobile or a railway vehicle, a method for obtaining a speed by measuring the number of rotations of a wheel is used. In this method, it is known that the ground speed cannot be measured when a wheel slips, and that in a car, the tire diameter changes due to tire deflation, tire wear, or the like, resulting in a measurement error. Therefore, it is required to obtain a more accurate ground speed.

  In response to such a request, for example, as disclosed in Japanese Patent Application Laid-Open No. 2006-184144 (Patent Document 1), a radar module that emits electromagnetic waves in the millimeter wave band or microwave band is used, and electromagnetic waves are emitted from the radar module. 2. Description of the Related Art A speed measurement device that radiates a traveling road surface such as the ground and receives a reflected wave thereof, measures a frequency change amount of the reflected wave, and calculates a ground speed is known. According to this method, the ground speed can be measured even during a slip, and since it is not affected by the change in the diameter of the tire, a more accurate ground speed can be obtained. Of course, an accurate ground speed can be obtained even in a railway vehicle. The traveling road surface is a road surface in an automobile and a track surface in a railway vehicle.

  In such a speed measuring device using electromagnetic waves, the electromagnetic waves are irradiated (incident) on the road surface at a predetermined incident angle (0 ° <θ <90 °). The incident electromagnetic wave generates a scattered wave on the surface of the traveling path, and the velocity is calculated by measuring the frequency of the directly reflected wave that is a part of the scattered wave.

JP 2006-184144 A

  In this way, in the speed measurement device using electromagnetic waves, it is possible to measure the speed by making the electromagnetic waves incident on the traveling road surface at a predetermined incident angle and receiving a part of the electromagnetic waves scattered on the traveling road surface by the speed measuring device. It will be.

  By the way, when a speed measuring device using electromagnetic waves is provided in a transportation vehicle, it is generally installed outside the floor surface, which is the bottom surface of the transportation vehicle. Therefore, electromagnetic waves incident on the traveling road surface from the floor surface of the transport vehicle propagate in the reflection angle direction. If there is a reflector (for example, a propeller shaft or an exhaust pipe in an automobile or an air conditioner or an inverter device in a railway vehicle) attached to the transport vehicle in the direction of the reflection angle, May be reflected in an unexpected direction, and the reflected electromagnetic wave may be reflected again on the road surface, and the returned electromagnetic wave may be received by the speed measuring device. In this case, since it is indistinguishable from electromagnetic waves that are reflected and returned directly from the traveling road surface (for example, a road surface in an automobile, a rail in a railway vehicle, etc.), there is a great risk of speed measurement errors. Therefore, there is a strong demand for reducing this speed measurement error. These phenomena will be described later in detail with reference to the drawings.

  An object of the present invention is to provide a novel speed measurement device that reduces a speed measurement error based on electromagnetic waves reflected in a reflection angle direction on a traveling road surface, a method for attaching the speed measurement device, and a vehicle to which the speed measurement device is attached.

  The first feature of the present invention is that a planar reflection control member that reflects incident electromagnetic waves in a predetermined angle direction is disposed on the floor surface of a transportation vehicle on which electromagnetic waves reflected in the reflection angle direction from the traveling road surface are incident. By the way.

  Furthermore, in addition to this, the second feature of the present invention is that the incident direction angle θ between the incident direction of the electromagnetic wave radiated from the antenna and the traveling road surface is 20 ° or more and 40 ° or less (20 ° ≦ θ ≦ 40). The angle range is set to °).

  According to the first feature of the present invention, the electromagnetic wave reflected in the reflection angle direction from the traveling road surface is incident again on the traveling road surface at a predetermined angle determined by a planar reflection control member provided on the floor surface of the vehicle. By returning the electromagnetic wave through almost the same path, the electromagnetic wave does not reflect in an unexpected direction, so that the measurement error can be reduced.

  Further, according to the second feature of the present invention, by setting the incident angle of the electromagnetic wave to 20 ° or more and 40 ° or less (20 ° ≦ θ ≦ 40 °), the planar portion of the reflection control member, the traveling road surface, Even if they are not parallel, the speed can be measured within a predetermined measurement error.

It is a block diagram which shows the state attached to the speed measurement apparatus in the motor vehicle which is an example of a transport vehicle. It is a block diagram which shows the state attached to the speed measurement apparatus in the rail vehicle which is an example of a transport vehicle. It is an external appearance perspective view which shows the structure of the radar module used for a speed measuring device. It is an external appearance perspective view which shows the structure of the focusing lens shown in FIG. It is sectional drawing which shows the side surface of the focusing lens part of the radar module of FIG. It is a disassembled perspective view of a speed measuring device. It is sectional drawing which shows the cross section of the speed measuring device shown in FIG. It is a circuit block diagram which shows the specific circuit structure of a speed measuring device. It is explanatory drawing which mounts the speed measuring device which becomes one Example of this invention in the floor surface part of a railway vehicle, and demonstrates the relationship between incidence | injection and reflection of electromagnetic waves. It is explanatory drawing which mounts the speed measuring device which becomes the other Example of this invention in the floor surface part of a railway vehicle, and demonstrates the relationship between incidence | injection and reflection of electromagnetic waves. It is a characteristic view which shows the relationship between an incident angle, a fraction term, and a fraction term change rate. It is explanatory drawing explaining the relationship between the inclination of a reflection control member, and a measurement error. It is an external appearance perspective view which shows the other structure of the radar module used for a speed measurement apparatus. It is explanatory drawing explaining the structure which put the speed measuring device inside the hanging metal fitting. It is explanatory drawing explaining the structure which has arrange | positioned the resin board to the opening part of the millimeter wave inside the hanging metal fittings of the speed measuring device. It is explanatory drawing explaining the structure which integrated the reflection control member and the hanging metal fitting. It is explanatory drawing which mounts the conventional speed measurement apparatus on the floor part of a rail vehicle, and demonstrates the relationship between incidence | injection and reflection of electromagnetic waves.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and application examples are included in the technical concept of the present invention. Is included in the range.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Before describing examples of the present invention, a speed measuring device provided in a transportation vehicle will be described in order to help understanding of the present invention. In the present embodiment, a speed measurement device using a radar module that uses electromagnetic waves in the 77 GHz band (hereinafter referred to as millimeter waves) will be described as an example. Further, it can be similarly applied to an electromagnetic wave type velocity measuring device using other frequencies.

  For example, as shown in FIG. 1, the speed measuring device 2 is installed on the floor surface B of the automobile A, radiates a millimeter wave M toward the road surface R (= traveling road surface) obliquely downward toward the traveling direction, The speed is calculated by measuring the frequency change amount of the reflected wave from the road surface R. Further, for example, as shown in FIG. 2, a millimeter wave M is radiated toward a rail which is installed on the floor surface S of the railway vehicle C and is a track surface G (= traveling road surface) obliquely downward toward the traveling direction, It is good also as a structure which measures the frequency variation | change_quantity of the reflected wave from the track surface G, and calculates speed. Hereinafter, the speed measuring device 2 installed in the railway vehicle C will be described as an example.

  FIG. 3 is an external perspective view showing an example of the configuration of the millimeter wave radar module 1 which is a main part of the speed measuring device. The millimeter wave radar module 1 mainly includes a substrate 20, a MMIC (Monolithic Microwave Integrated Circuit) chip 15, and a focusing lens 10. In the drawing, the focusing lens 10 is shown before being fixed to the substrate 20.

  A series of wirings 23 used to connect the planar antenna 22, the feeder line 21, and an external circuit are formed on the substrate 20, the IC mounting cavity 14 on which the MMIC chip 15 is bonded and mounted, and the focusing lens 10. Lens mounting cavities 25A to 25D for determining the mounting position are formed.

  As an example of the substrate 20, a ceramic multilayer substrate or a printed circuit board is used, a patch antenna is used as the planar antenna 22, and a microstrip line is used as the feeder line 21. In addition, a GND plane parallel to the planar antenna 22 extends over the inner layer of the substrate 20.

  For external power supply to the MMIC chip 15 and signal input / output, the MMIC chip 15 and the series of wirings 23 are connected by wire bonding 19 and connected to an external circuit through the pad portion 23A. Further, the connection between the millimeter waveband signal terminal of the MMIC chip 15 and the feeder line 21 extending from the planar antenna 22 is performed by wire bonding 19A. The GND surface of the inner layer of the substrate 20 and the GND terminal of the MMIC chip 15 are connected by wire bonding 19B and wire bonding 19C.

  With these connections, the millimeter-wave transmission signal generated by the MMIC chip 15 can be radiated into the air and received from the air via the planar antenna 22. Since the antenna and the focusing lens are reversible, the same configuration can be used for transmission and reception. In the following description, the antenna will be described for transmission unless otherwise specified.

  Further, since the focusing lens 10 has a wide directivity angle of the millimeter wave radiated from the planar antenna 22, it is used for the purpose of sharpening the directivity by the focusing effect. The focusing lens 10 is mounted from the upper side of the planar antenna 22 and fixed to the substrate 20.

  FIG. 4 is an external perspective view of the focusing lens 10 as seen from the fixed surface. As an example of the material of the focusing lens 10, a material such as a synthetic resin having a dielectric constant of about 2 to 10 is used. The focusing lens 10 is formed of a curved surface portion 10A and a flat surface portion 10B. The planar portion 10B is in direct contact with the planar antenna 22 of the substrate 20. Further, the focusing lens 10 has a flange 11A and a flange 11B integrally formed of the same material as the focusing lens 10, and has a structure having alignment bosses 12A to 12D on the flange 11A and the flange 11B. The positions of these alignment bosses 12A to 12D are the same as the lens mounting cavities 25A to 25D of the substrate 20 described above in FIG. Accordingly, the alignment bosses 12A to 12D of the focusing lens 10 are inserted into the lens mounting cavities 25A to 25D, and the focusing lens 10 is integrated with the substrate 20.

  Returning to FIG. 3, the focusing lens 10 is fixed to the substrate 20 by bonding at the alignment bosses 12A to 12D and the lens mounting cavities 25A to 25D. When fixing, the flanges 11 </ b> A and 11 </ b> B are fixed in a direction that does not overlap the power supply line 21.

  FIG. 5 is a side view of the millimeter wave radar module 1 as viewed from the side. The planar portion 10B of the focusing lens 10 is in direct contact with the planar antenna 22. That is, the planar portion 10 </ b> B is located in the near field of the planar antenna 22. On the other hand, the curved surface portion 10 </ b> A is located at a wavelength λ or more from the center portion of the planar antenna 22. That is, it is located in the far field of the planar antenna 22. Since the spatial impedance can be regarded as uniform by being located in the far field, even if the distance between the curved surface portion 10A and the planar antenna 22 varies somewhat, the variation in the focusing effect of the millimeter wave does not affect the operation of the radar module 1. Small enough.

  Further, by setting the positions of the flange 11A and the flange 11B at a position away from the central axis of the focusing lens 10 by an angle β or more, the flanges 11A to 11B can prevent the focusing effect of the focusing lens from being hindered. In general, since the radiation angle of the planar antenna 22 is about ± 45 degrees, the angle β is preferably about 60 degrees or more.

  6 and 7 are an external perspective view and a cross-sectional view showing the configuration of the speed measuring device 2. The speed measuring device 2 is mainly composed of the millimeter wave radar module 1, the peripheral circuit 31, the aluminum base 32, the synthetic resin housing 33, and the synthetic resin cover 37 described above. The millimeter wave radar module 1 and the peripheral circuit 31 are mounted on a circuit board 38. The aluminum base 32 is made of aluminum or aluminum alloy from the viewpoint of heat dissipation, mounting strength to the vehicle, and the like. In FIG. 6, the cover 37 is shown in a state before being fixed to the housing 33.

  Here, the peripheral circuit 31 mainly converts a power supply voltage supplied from the outside of the speed measuring device 2 into a desired voltage, and supplies power to the electronic and electrical components and the millimeter wave radar module 1 that constitute the peripheral circuit 31. A power supply voltage generation function unit, an arithmetic function unit that controls the millimeter wave radar module 1 and converts a signal output from the millimeter wave radar module 1 into measurement speed information, and the measurement speed information outside the speed measurement device 2 At least an output function unit.

  As shown in FIG. 6, the aluminum base 32 includes a fixing hole 36 that fixes the speed measuring device 2 to the floor surface S of the railway vehicle C via a mounting bracket, and also has a heat dissipation function of the speed measuring device 2. Yes. Further, the millimeter wave radar module 1, the circuit board 38 on which the peripheral circuit 31 is mounted, and the housing 33 are fixed to the aluminum base 32. The housing 33 has a connector portion 33A used for connection to the outside, and the lower end surface of the housing 33 is fitted and fixed in a groove 32B of the aluminum base 32. In addition, the electrical connection between the peripheral circuit 31 and the connector portion 33A is performed using wire bonding 34.

  The cover 37 is made of a synthetic resin, and lens regions 37A and 37B are formed near the center. The lens regions 37A and 37B have a function of further sharpening the directivity of the millimeter wave emitted from the focusing lens 10 of the millimeter wave radar module 1 by the focusing effect. The lens region 37A is formed in a planar shape, and the lens region 37B is formed in a shape protruding toward the millimeter wave radar module 1 side. Thus, the space formed in the cover 37 and the housing 33 is effectively used.

  The lower end surface of the cover 37 is fitted and fixed in a groove 33 </ b> B of the housing 33. Therefore, the millimeter wave radar module 1 and the peripheral circuit 31 can be protected from rainwater and dust by the aluminum base 32, the housing 33, and the cover 37.

  FIG. 8 is a diagram showing a schematic circuit configuration of the speed measuring device 2. The MMIC chip 15 in the millimeter wave radar module 1 mainly includes a transmitter 134, a transmission amplifier 110, an isolator 119, a reception amplifier 113, and a mixer 112. The port 120 connected to the isolator 119 transmits and receives millimeter waveband signals. Further, a signal is transmitted by connecting the port 120 and the planar antenna 22 by the feeder line 21.

  The operation of the millimeter wave radar module 1 will be described in detail below. The high frequency signal in the 77 GHz band generated by the oscillator 134 is amplified by the transmission amplifier 110, then propagated to the planar antenna 22 through the isolator 119, and radiated as a millimeter wave from the planar antenna 22 to the space. The emitted millimeter wave is focused by the focusing lens 10 and the cover 37 having a lens function, and is incident on the track surface G.

  The incident millimeter wave is reflected by the track surface G, and the frequency of the reflected wave is changed by the Doppler effect in proportion to the ground speed with the track surface G. The millimeter wave reflected by the track surface G is incident on the planar antenna 22 through the cover 37 and the focusing lens 10.

  The signal received by the planar antenna 22 is propagated to the reception amplifier 113 by the isolator 119. This signal is amplified by the receiving amplifier 113 and mixed with the high frequency signal output from the oscillator 134 by the mixer 112 to generate an IF (Intermediate Frequency) signal, which is input to the arithmetic circuit 201.

  The frequency of the IF signal is a frequency change due to the Doppler effect. The operation of the arithmetic circuit 201 constituting the arithmetic function unit is mainly performed by converting an IF signal into a digital signal by the AD conversion function unit 201A, and this digital signal is converted into an IF signal by a fast Fourier transform (FFT) processing unit 201B. Is then converted into a speed v by the speed conversion function unit 201C.

Here, the frequency f _d (Doppler frequency) due to the Doppler effect is such that the speed of light is c, the frequency of the signal output from the oscillator is f ₀ (millimeter wave transmission frequency), the speed is v, and the millimeter wave travels to the orbital plane G. If the incident direction angle between the incident direction and the orbital plane is θ,

It is expressed by the relational expression.

According to the expression (1), the fraction term on the right side can be regarded as a constant. When the millimeter wave transmission frequency f ₀ is 76.5 GHz and the incident direction angle θ is 45 °, the constant on the right side is about 100 Hz. / (Km / h). Therefore, the speed measuring device 2, the speed of the transport vehicle v is faster, the higher in proportion Doppler frequency f _d.

  The speed v of the transport vehicle calculated by the arithmetic circuit 201 is output from the speed measuring device 2 to the automatic train control device (ATC) 601. Here, the automatic train control device 601 automatically brakes the train speed according to the signal / speed information from the ground, or releases the brake when the speed becomes lower than the limit speed. Moreover, the speed is controlled so as not to exceed the speed limit of the own train generated according to the position of the preceding train.

  Next, the reflection of millimeter waves in a conventional transportation vehicle in which the speed measuring device is mounted on the floor surface of the railway vehicle will be described. In FIG. 17, vehicle equipment 41 such as an inverter control device and an air conditioning control device that controls the rotation of an electric motor is suspended and exposed in a casing skeleton 40 on the floor side of a railway vehicle. Further, the speed measuring device 2 is attached and fixed via a mounting bracket 43 to a hanging metal fitting 42 composed of columns 42a and 42b and a beam 42c.

  The millimeter wave radiated from the velocity measuring device 2 propagates along the route M11, reflects and scatters at the point X on the orbital plane G, and partly propagates along the route M12 in the direction opposite to the incident route M11. The data is directly returned to the measuring device 2 and received. If only the primary reflected millimeter wave returning directly from this point X can be received, an accurate speed can be measured.

  However, in the actual environment, the millimeter wave is reflected at the point X, propagates along the path M21a that is in the reflection angle direction, and reaches the floor surface of the railway vehicle. Here, when there is the vehicle device 41 exposed from the floor as described above, the vehicle device 41 functions as a millimeter wave reflecting member. For this reason, the millimeter wave is reflected at a point Ya on the surface of the vehicle device 41 and then propagates along the path M22a and enters the point Za on the track surface G at an angle α. In this case, the angle α in the direction of reflection by the vehicle device 41 is determined by various shapes of the vehicle device 41 and the like and cannot be substantially managed. Then, the secondary reflected millimeter wave reflected after entering the track surface G through the path M22a propagates through the path M23a, the path M24a, and the path M25a in the direction opposite to the incident path, and is received by the velocity measuring device 2. .

  Here, the millimeter wave of the secondary reflection also causes the Doppler effect according to the velocity v. Therefore, when the incident direction angle α between the path M22a and the orbital plane G is different from the incident direction angle θ first incident on the orbital plane, it is caused by the Doppler effect of the secondary wave of millimeter waves as can be seen from the equation (1). The change in frequency is different from the change in the frequency of millimeter wave of primary reflection.

Since the velocity measuring device 2 cannot distinguish between the first primary reflection millimeter wave and the secondary reflection millimeter wave, the incident direction angle θ and the incident direction angle α are greatly different when the fast Fourier transform processing is performed. In some cases, two frequencies are calculated on the frequency domain, or when the incident direction angle θ and the incident direction angle α are substantially close to each other, two different frequencies are overlapped on the frequency domain to become a peak position. can not accurately calculate the frequency change f _d frequencies appeared to frequencies different from the position of only the primary reflection components, both the measurement error.

  In order to solve such a problem, the present embodiment proposes a configuration in which a planar reflection control member is arranged on the floor surface S of the railway vehicle C on which the millimeter wave reflected in the reflection angle direction from the track surface is incident. To do. According to this, the millimeter wave reflected in the reflection angle direction from the track surface G is incident again on the track surface at a predetermined angle determined by a planar reflection control member provided on the floor surface of the vehicle, and substantially the same path. By returning the electromagnetic wave, the millimeter wave does not reflect in an unexpected direction, so that the measurement error can be reduced.

  According to the present embodiment, the millimeter wave reflected in the reflection angle direction from the first orbital plane G is controlled in the angle of the reflection angle direction by the planar reflection control member, and the millimeter wave incident on the first orbital plane is incident. It can be controlled to be almost the same as the direction angle.

  The first embodiment of the present invention will be described below with reference to FIG. In the present embodiment, a configuration for reducing the measurement error due to the secondary reflection component as described above is proposed.

  In FIG. 9, a reflection control member 44 that covers the entire vehicle equipment 41 is fixed to the floor surface S of the railway vehicle C. The reflection control member 44 is configured by suspending a flat plate 44c from the housing skeleton 40 via a column 44a and a column 44b. Here, the flat plate 44c is installed so as to be substantially parallel to the track surface G. Therefore, although the millimeter wave reflected in the reflection angle direction from the track surface G is incident on the plane plate 44c, it is reflected at a predetermined angle predetermined by the plane plate 44c, that is, an angle close to the first incident direction angle θ. Thus, the light can be incident again on the track surface G side.

  In FIG. 9, the millimeter wave radiated from the velocity measuring device 2 propagates along the path M11, is reflected at the point X on the orbital plane G, propagates along the path M21b, and enters the point Yb on the flat plate 44c. Here, since the flat plate 44c is substantially parallel to the track surface G, the incident direction angle between the path M21b and the flat plate 44c is an angle θ.

  On the other hand, the reflection direction angle between the millimeter wave path M22b propagating in the reflection angle direction on the plane plate 44c and the plane plate 44c is also an angle θ, and the millimeter wave reflected on the point Yb propagates along the path M22b and passes through the orbital plane G. Is incident on the point Zb. As described with reference to FIG. 17, this millimeter wave component also causes a Doppler effect according to the speed v.

The secondary reflected millimeter wave that is incident on the track surface G and reflected by the path M22b propagates through the path M23b, the path M24b, and the path M25b in the opposite direction to the incident path, and is received by the velocity measuring device 2. The velocity measuring device 2 cannot distinguish between the primary reflection component and the secondary reflection component, but the incident directions of the primary reflection component and the secondary reflection component on the track surface G are almost the same. it is possible to accurately calculate the frequency f _d for is possible to use both.

  Here, the flat plate 44c is shaped so as to cover all the vehicle equipment 41, but it is sufficient that the flat plate 44c is positioned at least in a region where the route M21b and the route M23b intersect. Therefore, the arrangement relationship between the flat plate 44c and the velocity measuring device 2 is determined by the incident angle θ of the millimeter wave from the velocity measuring device 2 and the distance between the flat plate 44c and the track surface G.

  That is, if the incident direction angle θ is small, the distance between the flat plate 44c and the speed measuring device 2 is long, and if the distance between the flat plate 44c and the raceway surface G is long, the flat plate 44c and the speed measuring device 2 are long. The distance between becomes longer. Therefore, when the velocity measuring device 2 irradiates the millimeter wave in an oblique direction with respect to the track surface G, the floor surface is positioned at a position where the millimeter wave reflected in the reflection angle direction can enter the plane plate 44c. What is necessary is just to be fixed to S.

  On the contrary, when the arrangement position of the velocity measuring device 2 is used as a reference, the millimeter wave is irradiated obliquely with respect to the track surface G, and the millimeter wave reflected in the reflection angle direction is flattened near the floor surface S. What is necessary is just to arrange | position the face plate 44c. In any case, it suffices if the millimeter wave reflected in the reflection angle direction can be incident on the flat plate 44c.

  Further, the width of the flat plate 44c along the traveling direction of the railway vehicle C is sufficient if it has at least the width of the range in which the incident direction and the reflection direction of the millimeter wave are projected. As a result, a millimeter-wave propagation path can be secured.

  Further, the reflection control member 44 is configured such that the side surfaces are opened by using columnar columns 44a and 44b other than the flat plate 44c from the viewpoint of cooling, maintenance, and management of the vehicle equipment 41. However, if there is no problem in terms of cooling, maintenance, and management, the reflection control member 44 may use a box-like sealed container to cover the vehicle equipment 41. In this case, the surface corresponding to the flat plate 44c is naturally necessary.

  The speed measuring device 2 is attached to the floor surface S of the railway vehicle C by fixing the aluminum base 32 shown in FIG. 6 to the mounting bracket 43. The aluminum base 32 is attached to the floor surface S in a predetermined incident direction. It is attached with an inclination so as to satisfy the angle θ.

  As described above, in this embodiment, the millimeter wave reflected in the reflection angle direction from the track surface G is returned to the track surface G again at a predetermined angle determined by the planar reflection control member provided on the floor surface of the vehicle. Incident light and electromagnetic waves return along almost the same path. That is, the millimeter wave reflected in the reflection angle direction from the first orbital plane G is controlled in angle by the planar reflection control member, and is substantially the same as the incident angle of the millimeter wave incident on the first orbital plane. Can be controlled. Thereby, since electromagnetic waves do not reflect in an unexpected direction, it becomes possible to reduce a measurement error.

  Next, a second embodiment of the present invention will be described. This embodiment proposes a method for dealing with a case where the flat plate 44c constituting the reflection control member 44 cannot secure a parallel relationship with the track surface G. .

  As shown in FIG. 10, since the reflection control member 44 is attached to the floor surface S of the railway vehicle C, it is difficult to maintain the flat plate 44c so that the flat plate 44c and the track surface G are in a parallel relationship. Cases are also envisaged. This state is shown in FIG. 10, and the flat plate 44c is attached to the front side in the traveling direction so as to be inclined downward, and the angle deviation from the horizontal of the flat plate 44c is defined as an angle δ.

  In FIG. 10, the millimeter wave radiated from the velocity measuring device 2 propagates along the path M11, reflects at the point X on the orbital plane G, propagates along the path M21c, and enters the point Yc on the flat plate 44c. Here, since the flat plate 44c is inclined downward by an angle δ, the angle between the path M21c and the flat plate 44c and the angle between the path M22c and the flat plate 44c at the point Yc are the angle θ + δ. Further, the angle between the path M22c and the track surface G is an angle θ + 2δ.

  Then, the secondary reflected millimeter wave reflected by entering the track surface G through the path M22c propagates through the path M23c, the path M24c, and the path M25c in the direction opposite to the incident path, and is received by the velocity measuring device 2. As described above, due to the inclination of the flat plate 44c, the angle between the path 21c and the flat plate 44c at the point Yc and the angle between the path 22c and the flat plate 44c are the angle θ + δ, and the path 22c. And the track surface G is an angle θ + 2δ.

The frequency f _d2 due to the Doppler effect of this secondary reflection component is

It is expressed by the relational expression.

Since the velocity measuring device 2 cannot distinguish between the primary reflection millimeter wave and the secondary reflection millimeter wave, when the high-speed Fourier transform processing is performed, the frequency f _d expressed by the equation (1) and ( The frequency at which two different frequencies _fd2 expressed by the equation (2) overlap and the peak position appears at a position different from the frequency of only the primary reflection component causes a measurement error.

  By the way, as shown in FIG. 11, the smaller the incident direction angle θ between the incident direction of the millimeter wave on the track surface G and the track surface G, the smaller the rate of change of the constant with respect to the change of the incident direction angle θ.

  Therefore, in order to reduce the above-described measurement error, the present inventors have shown that the smaller the incident direction angle θ between the incident direction of the millimeter wave on the track surface G and the track surface G is, as shown in FIG. The following examination was conducted by paying attention to the fact that the rate of change of the constant with respect to the change of the direction angle θ becomes smaller, and therefore the measurement error can be absorbed as the incident direction angle θ becomes smaller.

  FIG. 12 shows the result of estimating the measurement error when the change of the angle δ from the horizontal of the flat plate 44c is set to 0.05 °, 0.1 °, and 0.2 °. Since the measurement error increases as the change in the angle δ increases, the case of 0.2 ° may be considered. When the change in the angle δ from the horizontal of the flat plate 44c is 0.2 °, the measurement error is within 0.3% (for example, an error of 1 km / h occurs when the railway vehicle runs at 300 km / h). In order to achieve this, the incident direction angle θ to the track surface G needs to be 40 ° or less.

  However, if the incident direction angle θ is decreased too much, the propagation distance of the millimeter wave becomes longer and the loss due to propagation increases, so the reception intensity in the speed measuring device 2 decreases. Therefore, when the incident direction angle θ is 20 °, the measurement error is about 0.15%, and even if the incident direction angle θ is made smaller than this, the error improvement effect is small. From these examination results, it has been found that the incident direction angle θ is in an appropriate range of 20 ° ≦ θ ≦ 40 °.

  The speed measuring device 2 is attached to the mounting bracket 43 so that the incident direction angle θ is within a range of 20 ° ≦ θ ≦ 40 °. Therefore, the mounting surface of the mounting bracket 43 to which the aluminum base 32 of the speed measuring device 2 shown in FIG. 6 is fixed may be formed so that the incident direction angle θ falls within the range of 20 ° ≦ θ ≦ 40 °. Is.

  Further, as in the first embodiment, even when the flat plate 44c is maintained in a parallel relationship with the track surface G, the incident direction angle θ is formed so as to be within a range of 20 ° ≦ θ ≦ 40 °. However, there is no problem. For example, even if the parallel relationship between the flat plate 44c and the raceway surface G is lost due to some cause, it is possible to fall within a predetermined measurement error range for the reason described above.

  As described above, according to this embodiment, the incident direction angle θ between the incident direction of the electromagnetic wave radiated from the antenna and the orbital surface is an angle range of 20 ° or more and 40 ° or less (20 ° ≦ θ ≦ 40 °). Thus, even if the plane portion of the reflection control member and the track surface are not parallel, the speed can be measured within a predetermined measurement error range.

  By the way, the speed measuring device 2 uses the mounting bracket 43 to set the incident direction angle θ between the incident direction of the electromagnetic wave radiated from the antenna and the track surface to an angle between 20 ° and 40 ° (20 ° ≦ θ ≦ 40 °). Although the range is set, the incident direction angle θ can be set by the following configuration.

  In FIG. 13, the incident direction angle θ can be set by forming the shape of the focusing lens 10 into a shape that radiates the millimeter wave radiated from the planar antenna 22 to the incident direction angle θ described above. That is, the traveling direction of the millimeter wave radiated from the planar antenna 22 is changed in the process of passing through the focusing lens 10, and is radiated at the incident angle θ described above. In this case, since the lens regions 37A and 37B of the cover 37 need to be positioned in the millimeter wave radiation direction from the focusing lens 10, the shape of the cover 37 may be adapted to this. .

And if it is the structure shown in FIG. 13, since the mounting bracket 43 can be abbreviate | omitted fundamentally, even if it is a case where the mounting bracket 43 cannot be provided in a floor surface depending on a transport vehicle, it is easy to measure a speed. 2 can be attached to the floor of the transport vehicle. Of course, the mounting bracket 43 can be used together.
As another embodiment, as shown in FIG. 14, the speed control device 2 is arranged inside the hanging metal fitting 46. In this case, if an opening through which millimeter waves pass can be provided in a part of the hanging metal fitting 46, the same effects as those described above can be obtained. Further, as shown in FIG. 15, when the resin plate 50 that can transmit millimeter waves is disposed in the opening, the speed control device 2 needs to be exposed to an external environment such as raindrops, dust, and the like. it can.
Moreover, as shown in FIG. 16, the structure which integrated the reflection control member and the hanging metal fitting can be considered, but also in this case, the same effects as described above can be obtained.

  Although there are various technical ideas other than the claims that can be understood from the above-described embodiment, typical ones will be described below.

  (1) An electromagnetic wave is focused by a focusing lens and irradiated on a traveling road surface, and a speed measuring device for calculating the speed of the transportation vehicle by measuring the frequency variation of the reflected wave is attached to the floor surface of the transportation vehicle. In the transport vehicle, a flat reflection control member is provided on the floor surface of the transport vehicle, and the speed measurement device is configured to detect the electromagnetic wave reflected in the reflection angle direction when the electromagnetic wave is irradiated obliquely on the traveling road surface. It is fixed to the floor surface at a position where it can enter the reflection control member.

  (2) A speed measuring device that focuses electromagnetic waves by a focusing lens and irradiates the traveling road surface, measures the amount of frequency change of the reflected wave, and calculates the speed of the transportation vehicle is attached to the floor surface of the transportation vehicle. In a transportation vehicle, a planar reflection control member is provided on the floor surface of the transportation vehicle, and the speed measuring device reflects the electromagnetic wave reflected in the reflection angle direction when the electromagnetic wave is irradiated obliquely on the traveling road surface. The speed measuring device is fixed to the floor surface at a position where it can be incident on the control member, and the speed measuring device further sets the angle formed between the incident direction of the electromagnetic wave to the traveling road surface and the traveling road surface to 20 ° or more and 40 ° or less. The incident direction angle in the range of (20 ° ≦ θ ≦ 40 °) is set and attached to the floor surface of the transport vehicle.

  (3) The reflection control member is composed of a flat plate disposed substantially parallel to the traveling road surface.

  (4) The flat plate is a flat plate that is suspended from the floor surface of the transport vehicle and has an open periphery.

  (5) The speed measuring device is fixed to the floor surface via a mounting bracket, and the incident direction angle is set by the mounting bracket.

  (6) The velocity measuring device includes at least an electromagnetic wave generating unit that generates an electromagnetic wave in a millimeter wave band or a microwave band, an antenna that radiates an electromagnetic wave from the electromagnetic wave generating unit, and a focusing that focuses the electromagnetic wave radiated from the antenna. A radar module equipped with a lens is housed in a housing space consisting of an aluminum base and a housing, and is composed of a cover fixed to the housing so as to face the converging lens, and the mounting bracket is attached via the aluminum base. Features.

  (7) The transport vehicle is an automobile traveling on a road surface, and the flat plate is arranged so as to cover the vehicle equipment exposed from the floor surface of the automobile from the lower side.

  As described above, according to the present invention, a planar reflection control member that reflects incident electromagnetic waves is disposed on the floor surface of a transportation vehicle on which electromagnetic waves reflected in the reflection angle direction from the traveling road surface are incident. As a result, the electromagnetic wave returns in substantially the same path by the planar reflection control member, so that the electromagnetic wave is not reflected in an unexpected direction, so that the measurement error can be reduced.

  In addition to this, the incident direction angle θ between the incident direction of the electromagnetic wave radiated from the antenna and the traveling road surface is set to an angle range of 20 ° to 40 °. Thus, the speed can be measured within a predetermined measurement error range even if the plane portion of the reflection control member and the traveling road surface are not parallel.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

  DESCRIPTION OF SYMBOLS 1 ... Millimeter wave radar module, 2 ... Speed measuring device, 5 ... Running road surface, 9 ... Transportation vehicle floor surface part, 10 ... Condensing lens, 10A ... Curved surface part, 10B ... Plane part, 11A, 11B ... Flange, 12A-12D ... Alignment boss, 14 ... cavity, 15 ... MMIC chip, 19, 19A, 19B, C ... wire bonding, 20 ... substrate, 21 ... feeder, 22 ... planar antenna, 23 ... wiring, 23A ... pad part, 24 ... through Holes, 25A to 25D ... Lens mounting cavity, 31 ... Peripheral circuit, 32 ... Aluminum base, 33 ... Housing, 33A ... Connector part, 34 ... Wire bonding, 36 ... Fixing hole, 37 ... Cover, 37A, 37B ... Lens area, DESCRIPTION OF SYMBOLS 38 ... Circuit board, 40 ... Case frame | skeleton, 41 ... Vehicle equipment, 42 ... Hanging metal fitting, 43 ... Mounting bracket, 44 ... Reflection control member 44c ... a flat plate, 45 ... a structure in which a reflection control member and a hanging metal fitting are integrated, 46 ... a hanging metal fitting with a speed measuring device arranged inside, 50 ... a resin plate, 110 ... a transmission amplifier, 112 ... a mixer, DESCRIPTION OF SYMBOLS 113 ... Receiver amplifier, 119 ... Isolator, 120 ... Port, 134 ... Transmitter, 201 ... Arithmetic circuit, A ... Automobile, B ... Automobile floor, C ... Railway vehicle, G ... Track surface, S ... Railroad vehicle Floor surface, 601 ... Automatic train control device (ATC)

Claims (8)

In a speed measurement device that is mounted on a transport vehicle, irradiates the traveling road surface with electromagnetic waves, measures the amount of change in the frequency of the reflected wave, and calculates the speed of the transport vehicle.
The speed measuring device irradiates the electromagnetic wave obliquely with respect to the traveling road surface, and the electromagnetic wave reflected in the reflection angle direction is directed to a planar reflection control member provided on the floor surface of the transport vehicle. The speed measuring device is fixed to the floor surface at a position where it can be incident. In a speed measurement device that is mounted on a transport vehicle, irradiates the traveling road surface with electromagnetic waves, measures the amount of change in the frequency of the reflected wave, and calculates the speed of the transport vehicle.
The speed measuring device irradiates the electromagnetic wave obliquely with respect to the traveling road surface, and the electromagnetic wave reflected in the reflection angle direction is directed to a planar reflection control member provided on the floor surface of the transport vehicle. Is fixed to the floor surface at a position where it can be incident,
Furthermore, the speed measuring device is configured so that an angle formed between an incident direction of the electromagnetic wave on the traveling road surface and the traveling road surface is in a range of 20 ° to 40 ° (20 ° ≦ θ ≦ 40 °). Is set to the floor surface of the transport vehicle, and the speed measuring device is characterized in that In the speed measuring device according to claim 1 or 2,
The speed measurement device according to claim 1, wherein the reflection control member is formed of a flat plate disposed substantially parallel to the traveling road surface. In the speed measuring device according to claim 3,
The speed measuring device according to claim 1, wherein the flat plate is a flat plate that is suspended from the floor surface of the transport vehicle and has an open side surface. In the speed measuring device according to any one of claims 1 to 4,
The velocity measuring device focuses at least the electromagnetic wave generating means for generating electromagnetic waves in the millimeter wave band or microwave band, the antenna for radiating electromagnetic waves from the electromagnetic wave generating means, and the electromagnetic waves radiated from the antenna. A radar module having a focusing lens is housed in a housing space composed of an aluminum base and a housing, and includes a cover fixed to the housing so as to face the focusing lens. A speed measuring device attached to the floor surface. In the mounting method of the speed measuring device mounted on the transport vehicle, irradiating the traveling road surface with electromagnetic waves, measuring the amount of change in the frequency of the reflected wave to calculate the speed of the transport vehicle,
The speed measuring device irradiates the electromagnetic wave obliquely with respect to the traveling road surface, and the electromagnetic wave reflected in the reflection angle direction is directed to a planar reflection control member provided on the floor surface of the transport vehicle. A method of attaching a speed measuring device having an attaching step of fixing to the floor surface at a position where it can be incident. In the attachment method of the speed measuring device according to claim 6,
In the attaching step, an angle formed between the direction in which the electromagnetic wave is incident on the traveling road surface and the traveling road surface of the speed measuring device is incident in a range of 20 ° to 40 ° (20 ° ≦ θ ≦ 40 °). A method of attaching a speed measuring device, comprising a step of setting a direction angle and attaching the directional angle to the floor surface of the transport vehicle.   A vehicle comprising the speed measuring device according to any one of claims 1 to 5.

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