Ultrasonic anemometer and wind speed measuring method

Abstract

To provide an ultrasonic anemometer capable of improving measurement accuracy.SOLUTION: An ultrasonic anemometer 100 includes: a first ultrasonic transmitter / receiver 31; a second ultrasonic transmitter / receiver 32 arranged spaced from the first ultrasonic transmitter / receiver 31 at a first distance D1 in a first direction; a third ultrasonic transmitter / receiver 33 arranged spaced from the first ultrasonic transmitter / receiver 31 at a second distance D2 shorter than the first distance D1; and a control circuit 210 that uses transmission / reception results between the first ultrasonic transmitter / receiver 31 and the second ultrasonic transmitter / receiver 32 and transmission / reception results between the first ultrasonic transmitter / receiver 31 and the third ultrasonic transmitter / receiver to perform arithmetic processing. The control circuit 210 uses the transmission / reception results between the first ultrasonic transmitter / receiver 31 and the second ultrasonic transmitter / receiver 32 to calculate a first wind speed, and uses the transmission / reception results between the first ultrasonic transmitter / receiver 31 and the third ultrasonic transmitter / receiver 33 to calculate a second wind speed, and when a different between the first wind speed and the second wind speed does not satisfy a first condition, outputs the first wind speed, and when a different between the first wind speed and the second wind speed satisfies a first condition, outputs the second wind speed.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an ultrasonic anemometer and a method for measuring wind speed. [Background technology]

[0002] For example, an ultrasonic anemometer is known in which a plurality of transducers each equipped with a piezoelectric vibrator are arranged so that they can transmit and receive ultrasonic signals to and from each other (see, for example, Patent Document 1). This ultrasonic anemometer measures the propagation time of the ultrasonic signal in both directions between the transducers for all combinations of transducer pairs by repeating the operation of transmitting an ultrasonic signal from one of the transducers and receiving it with the remaining transducers by sequentially switching the transducer that transmits the ultrasonic signal.

[0003] This ultrasonic anemometer calculates n·(n-1) / 2 wind direction and speed vectors for n transducers from the measured ultrasonic signal propagation time. Among the calculated wind direction and speed vectors, this ultrasonic anemometer excludes wind direction and speed values ​​that differ by more than a predetermined threshold. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-229256 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the ultrasonic anemometer according to the prior art does not address the problem of erroneous determination of wind direction and speed in strong winds.

[0006] An object of the present disclosure is to provide an ultrasonic anemometer and a wind speed measurement method that can improve measurement accuracy. [Means for solving the problem]

[0007] An ultrasonic anemometer according to the present disclosure includes a first ultrasonic transceiver, a second ultrasonic transceiver located a first distance in a first direction from the first ultrasonic transceiver, a third ultrasonic transceiver located a second distance from the first ultrasonic transceiver in a direction different from the first direction that is shorter than the first distance, and a control circuit that performs arithmetic processing using the results of ultrasonic transmission and reception between the first ultrasonic transceiver and the second ultrasonic transceiver and the results of ultrasonic transmission and reception between the first ultrasonic transceiver and the third ultrasonic transceiver, wherein the control circuit calculates a first wind speed using the results of ultrasonic transmission and reception between the first ultrasonic transceiver and the second ultrasonic transceiver, calculates a second wind speed using the results of ultrasonic transmission and reception between the first ultrasonic transceiver and the third ultrasonic transceiver, outputs the first wind speed when the difference between the first wind speed and the second wind speed does not satisfy a first condition, and outputs the second wind speed when the difference between the first wind speed and the second wind speed satisfies the first condition. [Effects of the Invention]

[0008] The present disclosure can provide an ultrasonic anemometer and a wind speed measurement method that can improve measurement accuracy. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view illustrating an ultrasonic anemometer according to an embodiment; [Figure 2] 1 is a schematic cross-sectional view illustrating an ultrasonic anemometer according to an embodiment. [Figure 3] FIG. 2 is a plan view showing an example of the arrangement of a reflecting plate and an ultrasonic transmitter / receiver. [Figure 4] FIG. 1 is a schematic diagram illustrating an example of vectors between multiple ultrasonic transmitters and receivers. [Figure 5] 10 is a diagram showing an example of a vector indicating a wind speed V, an X-axis component of the wind speed V, and a Y-axis component of the wind speed V. FIG. [Figure 6] 1 is a block diagram illustrating a hardware configuration of an ultrasonic anemometer according to an embodiment. [Figure 7]Figure 7(a) is a graph illustrating the waveforms of signals corresponding to the first and second observation waves, and Figure 7(b) is a graph illustrating the waveforms of signals corresponding to the third and fourth observation waves. [Figure 8] 4 is a graph illustrating waveforms of signals corresponding to a first observation wave and a second observation wave. [Figure 9] 1 is a flowchart illustrating a procedure of a wind speed measurement method according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an ultrasonic anemometer according to an embodiment will be described with reference to the accompanying drawings. In this specification and the drawings, substantially identical components may be designated by the same reference numerals to avoid redundant description. In addition, the terms "upper" and "lower" may be used in this specification. These refer to the "upper" and "lower" in the state shown in FIG. 2, where the side where the top plate 11 is located is the "upper" and the side where the reflector plate 21 is located is the "lower" in the Z-axis direction. The actual arrangement of the ultrasonic anemometer 100 is not limited to this.

[0011] [Ultrasonic anemometer 100 according to the embodiment] FIG. 1 is a schematic perspective view illustrating an ultrasonic anemometer 100 according to an embodiment. FIG. 2 is a schematic cross-sectional view illustrating an ultrasonic anemometer 100 according to an embodiment. FIG. 3 is a plan view illustrating an example of an arrangement of a reflector 21 and ultrasonic transceivers 30. FIG. 4 is a schematic view illustrating an example of vectors Vx, Vy, Va, Vc, and Vd between multiple ultrasonic transceivers 30. Note that each figure may illustrate an X-axis direction, a Y-axis direction, and a Z-axis direction that are orthogonal to each other. The X-axis direction, the Y-axis direction, and the Z-axis direction do not have to be orthogonal to each other. The X-axis direction, the Y-axis direction, and the Z-axis direction may be any direction. The X-axis direction is an example of a first direction. The Y-axis direction is an example of a second direction that intersects with the first direction. The Z-axis direction is an example of a third direction that intersects with the first direction and the second direction.

[0012] 1 and 2 is a wind direction and speed measurement device that measures the wind direction and speed of a fluid to be measured based on the propagation time of ultrasonic waves transmitted and received between an ultrasonic transmitter and an ultrasonic receiver. The ultrasonic anemometer 100 can determine wind speed from fluctuations in the speed of sound in the air (approximately 340 m / s). The distance between the ultrasonic transmitter and the ultrasonic receiver is known, and the wind direction and speed of the fluid can be measured based on the difference in the propagation time of the ultrasonic waves.

[0013] As shown in Fig. 1, the ultrasonic anemometer 100 includes a first housing 10, a second housing 20, and multiple support columns 13. The first housing 10 and the second housing 20 are spaced apart in the Z-axis direction. The multiple support columns 13 extend in the Z-axis direction and support the first housing 10 relative to the second housing 20. The lower ends of the support columns 13 are fixed to the second housing 20, and the upper ends of the support columns 13 are fixed to the first housing 10. The first housing 10 mounts multiple ultrasonic transmitters / receivers 30 and a circuit board. Note that a cover that covers the top of the first housing 10 is not shown in Fig. 1.

[0014] As shown in FIG. 2, the ultrasonic anemometer 100 includes a first housing 10 that also functions as a top plate 11, a plurality of ultrasonic transmitters and receivers 30, and a second housing 20 that also functions as a reflector 21.

[0015] [Tabletop 11] The top plate 11 is provided on the first housing 10. The top plate 11 is arranged on the bottom of the first housing 10. The top plate 11 is, for example, disk-shaped. The top plate 11 is provided with a holder that holds multiple ultrasonic transceivers 30. The top plate 11 also has a surface (first plane 12) that reflects ultrasonic waves transmitted from the ultrasonic transceivers 30.

[0016] [1st plane 12] The top plate 11 has a first plane 12. The first plane 12 is a surface along the X-axis direction and the Y-axis direction. The first plane 12 is the bottom surface of the top plate 11.

[0017] [Multiple ultrasonic transmitters / receivers 30] The multiple ultrasonic transceivers 30 include a first ultrasonic transceiver 31, a second ultrasonic transceiver 32, a third ultrasonic transceiver 33, and a fourth ultrasonic transceiver 34. The multiple ultrasonic transceivers 30 are mounted on the top board 11. The ultrasonic transceivers 30 are ultrasonic transmitting units that transmit ultrasonic waves and ultrasonic receiving units that receive ultrasonic waves. The arrangement of the multiple ultrasonic transceivers 30 will be described later.

[0018] [Reflector 21] Specifically, the reflecting plate 21 is provided on the upper part of the second housing 20. The reflecting plate 21 is disposed so as to face the top plate 11 in the Z-axis direction. A space is formed between the top plate 11 and the reflecting plate 21, through which the fluid to be measured can pass. The fluid to be measured may be, for example, air. The reflecting plate 21 has a surface that reflects ultrasonic waves transmitted from the ultrasonic transceiver 30. The reflecting plate 21 is an example of a bottom plate.

[0019] [2nd plane 22] The reflecting plate 21 has a second plane 22 and a third plane 23. The second plane 22 may be the upper surface of the reflecting plate 21. The second plane 22 faces the first plane 12 in the Z-axis direction and is parallel to the second plane 22. The second plane 22 is a plane extending along the X-axis direction and the Y-axis direction. As shown in FIG. 3 , the second plane 22 is disposed at the center of the reflecting plate 21 when viewed in the Z-axis direction. The reflecting plate 21 has, for example, a substantially cross shape. Here, the portion extending outside the substantially cross shape in the Z-axis direction can be disposed between adjacent ultrasonic transceivers (e.g., the first ultrasonic transceiver 31 and the third ultrasonic transceiver 33). Furthermore, when viewed in the Z-axis direction, the second plane 22 includes an area overlapping with the first plane 12. The shape of the second plane 22 is not limited to a substantially cross shape and may be rectangular or another shape.

[0020] [Side 3 23] The third surface 23 is formed around the second plane 22 when viewed in the Z-axis direction. The third surface 23 is formed so as to surround the second plane 22. The third surface 23 may be, for example, a conical slope. As shown in FIG. 2, in a cross section along the XZ plane, the third surface 23 includes an inclined surface that is inclined with respect to the second plane 22. The upper end of the third surface 23 is located closer to the second plane 22 than the lower end of the third surface 23 in the X-axis direction. The lower end of the third surface 23 is located further outward than the upper end of the third surface 23 in the Z-axis direction. The third surface 23 is inclined outward so as to face the opposite side to the second plane 22. The outer end of the third surface 23 is located lower than the inner end. "Outward" may also mean that the outer end is located lower than the inner end. "Downward" refers to a direction away from the top plate 11 in the Z-axis direction. The third surface 23 includes a position overlapping with the ultrasonic transceivers 30 when viewed in the Z-axis direction. The third surface 23 includes a surface disposed directly below the plurality of ultrasonic transceivers 30. The reflecting plate 21 may have only the second plane 22 and may not have the third surface 23.

[0021] [Height H] As shown in FIG. 2, the height between the first plane 12 and the second plane 22 in the Z-axis direction is height H.

[0022] [Arrangement of ultrasonic transceiver 30] Next, the arrangement of the ultrasonic transceivers 30 will be described with reference to FIG. 3. The first ultrasonic transceiver 31 and the second ultrasonic transceiver 32 are arranged spaced apart in the X-axis direction. The third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34 are arranged spaced apart in the Y-axis direction. The first ultrasonic transceiver 31, the second ultrasonic transceiver 32, the third ultrasonic transceiver 33, and the fourth ultrasonic transceiver 34 are arranged at positions corresponding to the vertices 14c of the imaginary square 14 when viewed in the Z-axis direction. The multiple ultrasonic transceivers 30 may be arranged outside the second plane 22 when viewed in the Z-axis direction. The multiple ultrasonic transceivers 30 may be arranged at positions overlapping the third plane 23 when viewed in the Z-axis direction.

[0023] [Ultrasonic transmission and reception path] Next, referring to Fig. 4, ultrasonic transmission and reception paths in the ultrasonic anemometer 100 will be described. The ultrasonic anemometer 100 has diagonal transmission and reception paths UTx and UTy, and adjacent transmission and reception paths UTa, UTb, UTc, and UTd. The diagonal transmission and reception path UTx is a transmission and reception path between the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32. When viewed in the Z-axis direction, the diagonal transmission and reception path UTx is formed along the X-axis direction. The diagonal transmission and reception path UTy is a transmission and reception path between the third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34. When viewed in the Z-axis direction, the diagonal transmission and reception path UTy is formed along the Y-axis direction.

[0024] The adjacent transmission / reception path UTa is a transmission / reception path between the second ultrasonic transceiver 32 and the third ultrasonic transceiver 33. The adjacent transmission / reception path UTb is a transmission / reception path between the second ultrasonic transceiver 32 and the fourth ultrasonic transceiver 34. The adjacent transmission / reception path UTc is a transmission / reception path between the first ultrasonic transceiver 31 and the fourth ultrasonic transceiver 34. The adjacent transmission / reception path UTd is a transmission / reception path between the first ultrasonic transceiver 31 and the third ultrasonic transceiver 33.

[0025] The ultrasonic anemometer 100 can directly acquire vectors Vx and Vy on the diagonal transmission / reception paths UTx and UTy. This allows the ultrasonic anemometer 100 to detect wind direction and speed with high accuracy. As shown in Fig. 4, the vector Vx is along the X-axis direction between the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32. The vector Vy is along the Y-axis direction between the third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34.

[0026] The ultrasonic anemometer 100 can acquire vectors Va, Vb, Vc, and Vd on adjacent transmission / reception paths UTa, UTb, UTc, and UTd. The ultrasonic anemometer 100 can calculate vectors Vx and Vy from vectors Va, Vb, Vc, and Vd. The ultrasonic anemometer 100 can avoid erroneous determinations in strong winds by comparing vectors Vx and Vy acquired directly from diagonal transmission / reception paths UTx and UTy with vectors Vx and Vy acquired from adjacent transmission / reception paths UTa, UTb, UTc, and UTd.

[0027] [X-axis and Y-axis components of wind speed V] FIG. 5 is a diagram showing an example of a vector indicating wind speed V, and the X-axis component and Y-axis component of wind speed V. In the diagonal transmission / reception paths, as shown in FIG. 5, the ultrasonic anemometer 100 calculates wind speed V and wind direction using vectors Vx and Vy. In the adjacent transmission / reception path, for example, vector Vx, the X-axis component, is calculated from vectors Va to Vd. For example, Vx={(Vc) 2 +(Vd) 2} 1 / 2 ×COSθ cd , or Vx={(Va) 2 +(Vb) 2} 1 / 2 ×COSθ ab Similarly, the Y-axis component vector Vy is calculated from the vectors Va to Vd. Here, θ cd =tan -1 (Vc / Vd)-π / 4, and θ ab =tan -1 (Va / Vb)-π / 4. For example, Vy={(Vd) 2 +(Va) 2} 1 / 2 ×COSθ da , or Vy={(Vb) 2 +(Vc) 2} 1 / 2 ×COSθ bc Here, θ da =tan -1 (Vd / Va)-π / 4, and θ bc =tan -1(Vb / Vc)-π / 4. Then, the wind speed V and wind direction are calculated from the vectors Vx and Vy in the same way as in FIG.

[0028] [Reflected wave] For example, in the diagonal transmission / reception path UTx, one reflected wave is transmitted from the first ultrasonic transceiver 31, reflected at a point on the second plane 22, and received by the second ultrasonic transceiver 32.

[0029] [First ultrasonic wave (first ultrasonic transceiver 31 → second ultrasonic transceiver 32)] The ultrasonic wave transmitted from the first ultrasonic transceiver 31 and received by the second ultrasonic transceiver 32 shown in Fig. 4 is referred to as the "first ultrasonic wave 31x." The first ultrasonic wave 31x is reflected by the second plane 22 and received by the second ultrasonic transceiver 32. The first ultrasonic wave 31x received by the second ultrasonic transceiver 32 during wind speed measurement is referred to as the "first observation wave 31xr."

[0030] [Second ultrasonic wave (second ultrasonic transceiver 32 → first ultrasonic transceiver 31)] The ultrasonic wave transmitted from the second ultrasonic transceiver 32 and received by the first ultrasonic transceiver 31 is referred to as the "second ultrasonic wave 32x." The second ultrasonic wave 32x is reflected by the second plane 22 and received by the first ultrasonic transceiver 31. When measuring wind speed, the second ultrasonic wave 32x received by the first ultrasonic transceiver 31 is referred to as the "second observation wave 32xr."

[0031] [First ultrasonic wave (third ultrasonic transceiver 33 → fourth ultrasonic transceiver 34)] The ultrasonic wave transmitted from the third ultrasonic transceiver 33 and received by the fourth ultrasonic transceiver 34 is referred to as the "first ultrasonic wave 33y." The first ultrasonic wave 33y is reflected by the second plane 22 and received by the fourth ultrasonic transceiver 34. When measuring wind speed, the first ultrasonic wave 33y received by the fourth ultrasonic transceiver 34 is referred to as the "first observation wave 33yr."

[0032] [Second ultrasonic wave (fourth ultrasonic transceiver 34 → third ultrasonic transceiver 33)] The ultrasonic wave transmitted from the fourth ultrasonic transceiver 34 and received by the third ultrasonic transceiver 33 is referred to as the "second ultrasonic wave 34y." The second ultrasonic wave 34y is reflected by the second plane 22 and received by the fourth ultrasonic transceiver 34. When measuring wind speed, the second ultrasonic wave 34y received by the fourth ultrasonic transceiver 34 is referred to as the "second observation wave 34yr."

[0033] [Third ultrasonic wave (first ultrasonic transceiver 31 → third ultrasonic transceiver 33)] The ultrasonic wave transmitted from the first ultrasonic transceiver 31 and received by the third ultrasonic transceiver 33 is referred to as the "third ultrasonic wave 31d." The third ultrasonic wave 31d is reflected by the second plane 22 and received by the third ultrasonic transceiver 33. The third ultrasonic wave 31d received by the third ultrasonic transceiver 33 during wind speed measurement is referred to as the "third observation wave 31dr."

[0034] [Fourth ultrasonic wave (third ultrasonic transceiver 33 → first ultrasonic transceiver 31)] The ultrasonic wave transmitted from the third ultrasonic transceiver 33 and received by the first ultrasonic transceiver 31 is referred to as the "fourth ultrasonic wave 33d." The fourth ultrasonic wave 33d is reflected by the second plane 22 and received by the first ultrasonic transceiver 31. When measuring wind speed, the fourth ultrasonic wave 33d received by the first ultrasonic transceiver 31 is referred to as the "fourth observation wave 33dr."

[0035] [Third ultrasonic wave (first ultrasonic transceiver 31 → fourth ultrasonic transceiver 34)] The ultrasonic wave transmitted from the first ultrasonic transceiver 31 and received by the fourth ultrasonic transceiver 34 is referred to as the "third ultrasonic wave 31c." The third ultrasonic wave 31c is reflected by the second plane 22 and received by the fourth ultrasonic transceiver 34. When measuring wind speed, the third ultrasonic wave 31c received by the fourth ultrasonic transceiver 34 is referred to as the "third observation wave 31cr."

[0036] [Fourth ultrasonic wave (fourth ultrasonic transceiver 34 → first ultrasonic transceiver 31)] The ultrasonic wave transmitted from the fourth ultrasonic transceiver 34 and received by the first ultrasonic transceiver 31 is referred to as the "fourth ultrasonic wave 34c." The fourth ultrasonic wave 34c is reflected by the second plane 22 and received by the first ultrasonic transceiver 31. When measuring wind speed, the fourth ultrasonic wave 34c received by the first ultrasonic transceiver 31 is referred to as the "fourth observation wave 34cr."

[0037] [Third ultrasonic wave (second ultrasonic transceiver 32 → third ultrasonic transceiver 33)] The ultrasonic wave transmitted from the second ultrasonic transceiver 32 and received by the third ultrasonic transceiver 33 is referred to as the "third ultrasonic wave 32a." The third ultrasonic wave 32a is reflected by the second plane 22 and received by the third ultrasonic transceiver 33. When measuring wind speed, the third ultrasonic wave 32a received by the third ultrasonic transceiver 33 is referred to as the "third observation wave 32ar."

[0038] [Fourth ultrasonic wave (third ultrasonic transceiver 33 → second ultrasonic transceiver 32)] The ultrasonic wave transmitted from the third ultrasonic transceiver 33 and received by the second ultrasonic transceiver 32 is referred to as the "fourth ultrasonic wave 33a." The fourth ultrasonic wave 33a is reflected by the second plane 22 and received by the second ultrasonic transceiver 32. When measuring wind speed, the fourth ultrasonic wave 33a received by the second ultrasonic transceiver 32 is referred to as the "third observation wave 33ar."

[0039] [Third ultrasonic wave (second ultrasonic transceiver 32 → fourth ultrasonic transceiver 34)] The ultrasonic wave transmitted from the second ultrasonic transceiver 32 and received by the fourth ultrasonic transceiver 34 is referred to as the "third ultrasonic wave 32b." The third ultrasonic wave 32b is reflected by the second plane 22 and received by the fourth ultrasonic transceiver 34. When measuring wind speed, the third ultrasonic wave 32b received by the fourth ultrasonic transceiver 34 is referred to as the "third observation wave 32br."

[0040] [Fourth ultrasonic wave (fourth ultrasonic transceiver 34 → second ultrasonic transceiver 32)] The ultrasonic wave transmitted from the second ultrasonic transceiver 32 and received by the fourth ultrasonic transceiver 34 is referred to as the "fourth ultrasonic wave 34b." The fourth ultrasonic wave 34b is reflected by the second plane 22 and received by the fourth ultrasonic transceiver 34. The fourth ultrasonic wave 34b received by the fourth ultrasonic transceiver 34 during wind speed measurement is referred to as the "fourth observation wave 3bbr."

[0041] [First distance D1 between opposing sensors] In the X-axis direction, the distance between the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32 is a first distance D1. In the Y-axis direction, the distance between the third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34 is a first distance D1. The first distance D1 between the opposing sensors may be, for example, 23.3 mm.

[0042] [Second distance D2 between adjacent sensors] The distance between the first ultrasonic transceiver 31 and the third ultrasonic transceiver 33 is a second distance D2. The distance between the first ultrasonic transceiver 31 and the fourth ultrasonic transceiver 34 is a second distance D2. The distance between the second ultrasonic transceiver 32 and the third ultrasonic transceiver 33 is a second distance D2. The distance between the second ultrasonic transceiver 32 and the fourth ultrasonic transceiver 34 is a second distance D2. The second distance D2 between adjacent sensors may be, for example, 16.4 mm. In other words, the second distance D2 is shorter than the first distance D1.

[0043] [Reach distance A1 of one reflected wave on the opposite path] The opposing paths are diagonal transmission / reception paths UTx and UTy. The transmission distance A1 of a single reflected wave on the opposing path is the distance that the first ultrasonic wave 31x transmitted from the first ultrasonic transceiver 31 travels after being reflected once by the second plane 22 and reaching the second ultrasonic transceiver 32, as shown in FIG.

[0044] The reach A1 [m] of one reflected wave on the opposite path can be calculated by the following formula (1).

number

[0045] The reach A1 of a single reflected wave on the opposing path is 31.0 mm, for example, when the first distance D1 between the opposing sensors is 23.2 mm and the height H between the first plane 12 and the second plane 22 is 10.3 mm. Similarly, the reach A1 [m] of a single reflected wave on the opposing path is the reach of the second ultrasonic wave 32x transmitted from the third ultrasonic transceiver 33, reflected once by the second plane 22, and then reaching the fourth ultrasonic transceiver 34.

[0046] Furthermore, the travel distance A1 of one reflected wave on the opposing path is 37.8 mm when, for example, the first distance D1 between the opposing sensors is 30.0 mm and the height H is 11.5 mm.

[0047] [Reaching distance B1 of one reflected wave from an adjacent path] The adjacent paths are adjacent transmission / reception routes UTa, UTb, UTc, and UTd. The transmission distance B1 of one reflected wave of the adjacent path is the distance that the third ultrasonic wave 31c transmitted from the first ultrasonic transceiver 31 is reflected once by the second plane 22 and reaches the third ultrasonic transceiver 33.

[0048] The propagation distance B1 [m] of one reflected wave of an adjacent path can be calculated using the following formula (2).

number

[0049] For example, when the second distance D2 between adjacent sensors is 16.4 mm and the height H is 10.3 mm, the travel distance B1 of a single reflected wave of an adjacent path is 26.3 mm. Similarly, the travel distance B1 [m] of an ultrasonic wave transmitted from the first ultrasonic transceiver 31, after being reflected once by the second plane 22, to reach the fourth ultrasonic transceiver 34 is the travel distance B1 [m] of a single reflected wave of an adjacent path. Similarly, the travel distance B1 [m] of an ultrasonic wave transmitted from the second ultrasonic transceiver 32, after being reflected once by the second plane 22, to reach the third ultrasonic transceiver 33 is the travel distance B1 [m] of a single reflected wave of an adjacent path. Similarly, the travel distance B1 [m] of an ultrasonic wave transmitted from the second ultrasonic transceiver 32, after being reflected once by the second plane 22, to reach the fourth ultrasonic transceiver 34 is the travel distance B1 [m] of a single reflected wave of an adjacent path.

[0050] [Propagation time] The propagation time T31x of the first observation wave 31xr and the propagation time T32x of the second observation wave 32xr are expressed by the formulas (3) and (4), respectively, using the reach A1, the sound speed C1, and the wind speed V. T31x=A1 / (C1+V) (3) T32x=A1 / (C1-V) (4)

[0051] Furthermore, equation (5) regarding the wind speed V can be obtained from [equation (3)-equation (4)]. V=(A1 / 2)[(1 / T31x)-(1 / T32x)] ···(5)

[0052] [Measurement unit 200] Next, the measurement unit 200 will be described. Fig. 6 is a block diagram illustrating an example of the hardware configuration of an ultrasonic anemometer according to an embodiment. The ultrasonic anemometer 100 includes the measurement unit 200. The measurement unit 200 calculates the wind speed V in the flow path 101 based on data received from the ultrasonic transceiver 30. The measurement unit 200 can also calculate the wind direction. The measurement unit 200 may further have a function to display the calculation results of the wind speed V and the like. The measurement unit 200 may also output the calculation results of the wind speed V and the like to an external information processing device.

[0053] The measurement unit 200 includes a control circuit 210, a signal generation circuit 221, and a detection circuit 222. The ultrasonic anemometer 100 may include a temperature sensor 231. The measurement unit 200 is electrically connected to a plurality of ultrasonic transceivers 30 and the temperature sensor 231. The measurement unit 200 may be a computer including the control circuit 210, the signal generation circuit 221, and the detection circuit 222. The measurement unit 200 may calculate the X-axis component Vx of the wind speed V using data acquired from the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32. The measurement unit 200 may calculate the Y-axis component Vy of the wind speed V using data acquired from the third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34. This will be described in more detail below.

[0054] [Signal generation circuit 221] The signal generation circuit 221 generates an AC signal for causing the first ultrasonic transceiver 31 to oscillate a first observation wave 31xr, and outputs the first observation wave 31xr from the first ultrasonic transceiver 31. The signal generation circuit 221 also generates an AC signal for causing the second ultrasonic transceiver 32 to oscillate a second observation wave 32xr, and outputs the second observation wave 32xr from the second ultrasonic transceiver 32. An example of the AC signal generated by the signal generation circuit 221 is an analog electrical signal corresponding to a sine wave having a predetermined period and amplitude. It is preferable that the sine wave corresponding to the AC signal to the first ultrasonic transceiver 31 and the sine wave corresponding to the AC signal to the second ultrasonic transceiver 32 have approximately the same period (frequency).

[0055] An example of the signal generating circuit 221 is a circuit that includes an oscillator circuit including a quartz oscillator, a digital-to-analog converter that converts a digital signal such as a pulse signal oscillated from the oscillator circuit into an analog AC signal, and a switching circuit that switches a transceiver to which the AC signal is output in accordance with a selection signal input from the control circuit 210. However, the configuration of the signal generating circuit 221 is not limited to this.

[0056] [Detection circuit 222] The detection circuit 222 detects a signal related to the second observation wave 32xr received by the first ultrasonic transceiver 31. The signal related to the second observation wave 32xr may be referred to as a "second signal 32Sx." The detection circuit 222 also detects a signal related to the first observation wave 31xr received by the second ultrasonic transceiver 32. The signal related to the first observation wave 31xr may be referred to as a "first signal 31Sx."

[0057] The detection circuit 220 outputs the detected first signal 31Sx and second signal 32Sx to the control circuit 210.

[0058] An example of the detection circuit 220 is a circuit including a switching circuit that switches the output signal to the control circuit 210 between the first signal 31Sx and the second signal 32Sx, an amplifier circuit that amplifies the first signal 31Sx or the second signal 32Sx output through the switching circuit, and an analog-to-digital converter that converts an analog AC signal related to the amplified first signal 31Sx or second signal 32Sx into a digital signal. However, the configuration of the detection circuit 220 is not limited to this.

[0059] [Temperature Sensor 231] The temperature sensor 231 may detect the temperature inside the flow path 101, for example, when measuring the wind speed. The temperature sensor 231 outputs information related to the detected temperature to the control circuit 440. The information related to the temperature detected by the temperature sensor 430 may be stored in the storage unit 212 of the control circuit 210. The information related to the temperature detected by the temperature sensor 231 can be used, for example, when calculating the sound speed C1.

[0060] The temperature sensor 231 may be any sensor capable of detecting the temperature inside the flow path 101. Examples of the temperature sensor 231 include a thermistor, a linear resistor, a platinum resistance thermometer, a thermocouple, and a thermopile.

[0061] [Control circuit 210] The control circuit 210 includes, for example, a central processing unit (CPU) 211 and a storage unit 212. The storage unit 212 includes a read-only memory (ROM) 213 and a random access memory (RAM). The CPU 211 executes various processes according to, for example, programs stored in the storage unit 212. The programs, when executed by the CPU 211, can cause the measurement unit 200 to function as a means for measuring the wind speed V. The programs may be stored in an external storage medium, such as a hard disk or flash memory. The programs may also be transmitted to the control circuit 210 via a communication line. The transmitted programs are installed in the storage unit 212 of the control circuit 210. The storage unit 212 stores various pieces of information required for calculating the wind speed V. The storage unit 211 stores information regarding the height H between the first plane 12 and the second plane 22, and information regarding the first distance D1 and the second distance D2 between the multiple ultrasonic transmitters / receivers 30. Furthermore, the control circuit 210 can output the calculated wind speed V to, for example, an external device.

[0062] The control circuit 210 calculates a first wind speed V1 using the results of diagonal ultrasonic wave transmission and reception by the first ultrasonic transceiver 31 to the fourth ultrasonic transceiver 34. The control circuit 210 calculates a second wind speed V2 using the results of adjacent ultrasonic wave transmission and reception by the first ultrasonic transceiver 31 to the fourth ultrasonic transceiver 34. The control circuit 210 outputs the second wind speed V2 when the difference between the first wind speed V1 and the second wind speed V2 satisfies a first condition. The control circuit 210 outputs the first wind speed V1 when the difference between the first wind speed V1 and the second wind speed V2 does not satisfy the first condition.

[0063] The first condition may be, for example, that the second wind speed Vd is equal to or greater than twice the first wind speed Vx. When the second wind speed Vd is equal to or greater than twice the first wind speed Vx, the control circuit 210 determines that the first condition is met and outputs the second wind speed V2 as the wind speed V. The first condition may be another condition. The control circuit 210 can compare the first wind speed V1 with the second wind speed V2 to determine whether the first condition is met. For example, the control circuit 210 may determine whether the first condition is met by determining whether the first wind speed V1 is below a determination threshold. For example, the control circuit 210 may determine whether the second wind speed V2 exceeds the first determination threshold and the first wind speed V1 is below a second determination threshold that is lower than the first determination threshold to determine whether the first condition is met.

[0064] The first condition may be a judgment threshold set depending on whether or not a "Tof shift" is likely to occur. For example, if a Tof shift is likely to occur at a wind speed of 45 m / s or more, a wind speed of 45 m / s or more can be the first condition. Here, a "Tof shift" can be defined as a case where the difference (phase difference) between the propagation time of the outgoing ultrasonic wave and the propagation time of the returning ultrasonic wave exceeds one period. In other words, "the occurrence of a Tof shift" can be expressed as "the phase rotates one period."

[0065] The control circuit 210 calculates the first wind speed Vy using the results of ultrasonic transmission and reception between the third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34. The control circuit 210 calculates the second wind speed Vy2 using the results of ultrasonic transmission and reception between the third ultrasonic transceiver 33 and the second ultrasonic transceiver 32, and between the second ultrasonic transceiver 32 and the fourth ultrasonic transceiver 34. When the difference between the first wind speed Vy and the second wind speed Vy2 does not satisfy the first condition, the control circuit 210 calculates the wind speed V using the first wind speed Vy. When the difference between the first wind speed Vy and the second wind speed Vy2 satisfies the first condition, the control circuit 210 calculates the wind speed using the second wind speed Vy2. In other words, the first condition can also be determined using the vector components that are the basis for calculating the wind speed V. Furthermore, although the Y-axis component has been described as an example here, the first condition may also be determined using the X-axis component.

[0066] The control circuit 210 can calculate the second wind speed Vc using the results of transmission and reception of ultrasonic waves between the first ultrasonic transceiver 31 and the fourth ultrasonic transceiver .

[0067] The control circuit 210 can calculate the second wind speed Va using the results of transmission and reception of ultrasonic waves between the second ultrasonic transceiver 32 and the third ultrasonic transceiver 33.

[0068] The control circuit 210 can calculate the second wind speed Vb using the results of transmission and reception of ultrasonic waves between the second ultrasonic transceiver 32 and the fourth ultrasonic transceiver .

[0069] When determining whether or not the first condition is satisfied, the control circuit 210 may use at least one of the second wind velocities Va to Vd to determine whether or not the first condition is satisfied.

[0070] Figure 7(a) is a graph illustrating the waveforms of signals corresponding to the first and second observation waves, and Figure 7(b) is a graph illustrating the waveforms of signals corresponding to the third and fourth observation waves.

[0071] The horizontal axis in Fig. 7(a) represents the elapsed time from the start of transmission of the first observation wave 31xr or the second observation wave 32xr. The origin of the horizontal axis in the figure corresponds to a point in time a predetermined time has elapsed from the start of transmission of the first observation wave 31xr or the second observation wave 32xr. The vertical axis in Fig. 7(a) represents the amplitude of the first signal 31Sx corresponding to the first observation wave 31xr and the second signal 32Sx corresponding to the second observation wave 32xr.

[0072] The horizontal axis of Fig. 7(b) represents the time elapsed since the start of transmission of the third observation wave 31dr or the fourth observation wave 33dr. However, the origin of the horizontal axis of the figure corresponds to a point in time a predetermined time has elapsed since the start of transmission of the third observation wave 31dr or the fourth observation wave 33dr. The vertical axis of Fig. 7(b) represents the amplitude of the third signal 31Sd corresponding to the third observation wave 31dr and the fourth signal 33Sd corresponding to the second observation wave 32xr.

[0073] The control circuit 210 calculates the first wind speed Vx using the first time t31xa when the first ultrasonic wave 31x is transmitted from the first ultrasonic transceiver 31 and the first ultrasonic wave 31x is received by the second ultrasonic transceiver 32, and the second time t32xa when the second ultrasonic wave 32x is transmitted from the second ultrasonic transceiver 32 and the second ultrasonic wave 32x is received by the first ultrasonic transceiver 31.

[0074] The control circuit 210 can calculate the second wind speed Vd using the third time t31da when the third ultrasonic wave 31d is transmitted from the first ultrasonic transceiver 31 and received by the third ultrasonic transceiver 33, and the fourth time t33da when the fourth ultrasonic wave 33d is transmitted from the third ultrasonic transceiver 33 and received by the first ultrasonic transceiver 31.

[0075] The control circuit 210 calculates the first wind speed Vy using the first time t33ya when the first ultrasonic wave 33y is transmitted from the third ultrasonic transceiver 33 and received by the fourth ultrasonic transceiver 34, and the second time t34ya when the second ultrasonic wave 34y is transmitted from the fourth ultrasonic transceiver 34 and received by the third ultrasonic transceiver 33.

[0076] The control circuit 210 calculates the second wind speed Vc using the third time t31ca when the third ultrasonic wave 31c is transmitted from the first ultrasonic transceiver 31 and received by the fourth ultrasonic transceiver 34, and the fourth time t34ca when the fourth ultrasonic wave 33c is transmitted from the fourth ultrasonic transceiver 34 and received by the first ultrasonic transceiver 31.

[0077] The control circuit 210 can calculate the second wind speed Va using the third time t32aa when the third ultrasonic wave 32a is transmitted from the second ultrasonic transceiver 32 and received by the third ultrasonic transceiver 33, and the fourth time t33aa when the fourth ultrasonic wave 33a is transmitted from the third ultrasonic transceiver 33 and received by the second ultrasonic transceiver 32.

[0078] The control circuit 210 can calculate the second wind speed Vb using the third time t32ba when the third ultrasonic wave 32b is transmitted from the second ultrasonic transceiver 32 and received by the fourth ultrasonic transceiver 34, and the fourth time t34ba when the fourth ultrasonic wave 34b is transmitted from the fourth ultrasonic transceiver 34 and received by the second ultrasonic transceiver 32.

[0079] The control circuit 210 determines that the time closest to the fifth time t5 when the amplitude is 0 when the second ultrasonic transceiver 32 receives the first ultrasonic wave 31x is the first time t31xa. The control circuit 210 determines that the time closest to the fifth time t5 when the amplitude is 0 when the first ultrasonic transceiver 31 receives the second ultrasonic wave 32x is the second time t32xa. The control circuit 210 calculates the first wind speed Vx using the first time t31xa and the second time t32xa.

[0080] The control circuit 210 determines the time closest to the fifth time t5 among the times when the amplitude is 0 when the third ultrasonic wave 31d is received by the third ultrasonic transceiver 33 as the third time t31da.The control circuit 210 determines the time closest to the fifth time t5 among the times when the amplitude is 0 when the first ultrasonic wave transceiver 31 receives the fourth ultrasonic wave 33d as the fourth time t33da, and calculates the second wind speed Vd.

[0081] The control circuit 210 determines that the time closest to the fifth time t5 when the amplitude is 0 when the fourth ultrasonic transceiver 34 receives the first ultrasonic wave 33y is the first time t33ya. The control circuit 210 determines that the time closest to the fifth time t5 when the amplitude is 0 when the third ultrasonic transceiver 33 receives the second ultrasonic wave 34y is the second time t34ya. The control circuit 210 calculates the first wind speed Vy using the first time t33ya and the second time t34ya.

[0082] The control circuit 210 determines the time closest to the fifth time t5 among the times when the amplitude is 0 when the fourth ultrasonic wave 31c is received by the fourth ultrasonic transceiver 34 as the third time t31ca.The control circuit 210 determines the time closest to the fifth time t5 among the times when the amplitude is 0 when the first ultrasonic wave 34c is received by the first ultrasonic transceiver 31 as the fourth time t34ca, and calculates the second wind speed Vc.

[0083] The control circuit 210 determines the time closest to the fifth time t5 among the times when the amplitude is 0 when the third ultrasonic wave 32a is received by the third ultrasonic transceiver 33 as the third time t32aa.The control circuit 210 determines the time closest to the fifth time t5 among the times when the amplitude is 0 when the second ultrasonic wave 33a is received by the fourth ultrasonic transceiver 32 as the fourth time t33aa, and calculates the second wind speed Va.

[0084] The control circuit 210 determines the time closest to the fifth time t5 among the times when the amplitude is 0 when the fourth ultrasonic transceiver 34 receives the third ultrasonic wave 32b as the third time t32ba. The control circuit 210 determines the time closest to the fifth time t5 among the times when the amplitude is 0 when the second ultrasonic transceiver 32 receives the fourth ultrasonic wave 34b as the fourth time t34ba, and calculates the second wind speed Vb.

[0085] [Measuring principle of wind speed V] Next, an example of the measurement principle of wind speed V will be described. An example of the measurement principle of wind speed V will be described with reference to FIG. 8 . FIG. 8 is a graph illustrating the waveforms of signals corresponding to the first observation wave and the second observation wave. The horizontal axis of FIG. 8 indicates the elapsed time from the start of transmission of the first observation wave 31xr or the second observation wave 32xr. The origin of the horizontal axis of the graph corresponds to a predetermined time after the start of transmission of the first observation wave 31xr or the second observation wave 32xr. The vertical axis of FIG. 8 indicates the amplitude of the first signal 31Sx corresponding to the first observation wave 31xr and the second signal 32Sx corresponding to the second observation wave 32xr. FIG. 8(a) shows the waveforms of the first signal 31Sx and the second signal 32Sx when the wind speed V in the flow path 101 is Vxa [m / s]. Note that Vxa is a non-zero value. FIG. 8(b) shows the waveform of the first signal 31Sx and the waveform of the second signal 32Sx when the wind speed V in the flow path 101 is Vxb [m / s] which is greater than Vxa.

[0086] In the comparative example, for example, a time point at which the peak value of the first signal 31Sx becomes zero (time point t31xa in FIG. 8A) is detected for the propagation time T31x, and a time point at which the peak value of the second signal 32Sx becomes zero (time point t32xa in FIG. 8A) is detected for the propagation time T32x. Time point t31xa is set to be a time point belonging to the n-th period of the first signal 31Sx. Time point t32xa is set to be a time point belonging to the n-th period of the second signal 32Sx. In other words, time point t31xa and time point t32xa are time points identified by the same peak value that belong to the same numbered periods of the first signal 31Sx and the second signal 32Sx. Note that for the propagation time T1, a time point at which the peak value of the first signal 31Sx is a value other than zero may be detected. For the propagation time T32x, a time point at which the peak value of the second signal 32Sx is a value other than zero may be detected.

[0087] 8(a), if the difference between the phase corresponding to time t31xa of the first signal 31Sx and the phase corresponding to time t32xa of the second signal 32Sx is equal to or less than the value of one period of the first signal 31Sx or the second signal 32Sx (for example, 2π), the points in time at which the first signal 31Sx and the second signal 32Sx have the same peak value and belong to the same numbered periods will be close in time series. Therefore, the points in time at which the first signal 31Sx and the second signal 32Sx have the same peak value and belong to the same numbered periods will be properly detected.

[0088] On the other hand, as shown in FIG. 8(b), when the wind speed V increases, the difference between the phase corresponding to time t31xa of the first signal 31Sx and the phase corresponding to time t32xa of the second signal 32Sx exceeds the value of one period of the first signal 31Sx or the second signal 32Sx. In this case, the points in time at which the same crest value is present in the same numbered periods of the first signal 31Sx and the second signal 32Sx are chronologically distant from each other. Therefore, for example, in the second signal 32Sx, there is a possibility that a point t32xb in the (n-1)th period, which is close to the point t31xa of the first signal 31Sx, may be detected. The same applies to the first signal 31Sx. That is, there is a possibility that points in time at which the same crest value is present in different numbered periods of the first signal 31Sx and the second signal 32Sx are detected, resulting in an erroneous measurement of the wind speed V.

[0089] Here, if the starting points of the first signal 31Sx and the second signal 32Sx were aligned, the nth period could be correctly identified. However, because vibrations generated when the ultrasonic transceiver transmits ultrasonic waves travel through the first housing 10 and are transmitted to the other ultrasonic transceiver, the starting point of the first signal 31Sx cannot be identified. This phenomenon is called housing propagation. Similarly, the starting point of the second signal 32Sx cannot be identified due to housing propagation. This phenomenon occurs more noticeably when the distance between the ultrasonic transceivers is shortened due to miniaturization. Therefore, the nth period of the first signal 31Sx is determined to be the point a predetermined time after the transceiver starts transmitting ultrasonic waves, and the period of the second signal 32Sy that is closest to time t31xa is determined to belong to the nth period.

[0090] [Procedure for measuring wind speed] Next, the procedure of the wind speed measurement method according to the embodiment will be described with reference to Fig. 9. Fig. 9 is a flowchart illustrating the procedure of the wind speed measurement method according to the embodiment. In the wind speed measurement method, first, the first wind speed Vx and the first wind speed Vy are calculated (step S11). In step S11, the measurement unit 200 calculates the first wind speed Vx using data acquired from the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32 that face each other in the X-axis direction, as described above. Also in step S11, the measurement unit 200 calculates the first wind speed Vy using data acquired from the third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34 that face each other in the Y-axis direction.

[0091] In step S11, the measurement unit 200 may use the first wind speed Vx and the first wind speed Vy to calculate the wind speed V. The measurement unit 200 can calculate the first wind speed V1 by using the first wind speed Vx as the X-axis component of the wind speed V and the first wind speed Vy as the Y-axis component of the wind speed V.

[0092] Next, in the wind speed measurement method, second wind speeds Va, Vb, Vc, and Vd are calculated (step S12). In step S12, the measurement unit 200 calculates the second wind speed Vd using data acquired from the first ultrasonic transceiver 31 and the third ultrasonic transceiver 33, as described above. Also in step S12, the measurement unit 200 calculates the second wind speed Vc using data acquired from the first ultrasonic transceiver 31 and the fourth ultrasonic transceiver 34. Also in step S12, the measurement unit 200 calculates the second wind speed Va using data acquired from the second ultrasonic transceiver 32 and the third ultrasonic transceiver 33. Also in step S12, the measurement unit 200 calculates the second wind speed Vb using data acquired from the second ultrasonic transceiver 32 and the fourth ultrasonic transceiver 34.

[0093] In step S12, the measurement unit 200 can calculate the second wind speed V2 using the second wind speed Va, the second wind speed Vb, the second wind speed Vc, and the second wind speed Vd.

[0094] Next, in the wind speed measurement method, the measurement unit 200 determines whether or not a first condition is met (step S13). If the first condition is met (step S13; YES), the measurement unit 200 executes the process of step S14. If the first condition is not met (step S13; NO), the measurement unit 200 executes the process of step S15.

[0095] The measurement unit 200 may determine that the first condition is met when the difference between the first wind speed V1 and the second wind speed V2 satisfies the first condition. The measurement unit 200 may determine whether the first condition is met by determining whether the second wind speed V2 is at least twice the first wind speed V1. The measurement unit 200 may, for example, compare the first wind speed V1 with the second wind speed V2 to determine whether the first condition is met. The measurement unit 200 may, for example, determine that the first condition is met when the second wind speed V2 is greater than the first wind speed V1.

[0096] The measurement unit 200 may determine whether the first condition is met by comparing the first wind speed V1 calculated using the first wind speeds Vx and Vy with the second wind speed V2 calculated using the second wind speeds Va-Vd. The measurement unit 200 may determine whether the first condition is met by determining whether the difference between the first wind speed Vx and the vector wind speed Vx2 in the X-axis direction calculated using part of the second wind speeds Va-Vd satisfies the first condition. The measurement unit 200 may determine whether the first condition is met by determining whether the difference between the first wind speed Vy and the vector wind speed Vy2 in the Y-axis direction calculated using part of the second wind velocities Va-Vd satisfies the first condition. The measurement unit 200 may determine whether the wind speeds Vx2 and Vy2 calculated using the second wind speeds Va to Vd are at least twice the wind speed V calculated using the first wind speeds Vx and Vy, thereby determining whether the first condition is met.

[0097] The measurement unit 200 may determine whether or not the first condition is met by comparing at least one of the first wind speed Vx and the first wind speed Vy with at least one of the second wind speeds Va to Vd.

[0098] Furthermore, the diagonal transmission and reception paths UTx and UTy are longer than the adjacent transmission and reception paths UTa, UTb, UTc, and UTd. This means that the diagonal transmission and reception paths UTx and UTy experience a longer period of time in which the ultrasonic waves are exposed to the wind than the adjacent transmission and reception paths UTa, UTb, UTc, and UTd. Therefore, the accuracy of the wind speed is higher for the diagonal transmission and reception paths UTx and UTy than for the adjacent transmission and reception paths UTa, UTb, UTc, and UTd. On the other hand, because the diagonal transmission and reception paths UTx and UTy experience a longer period of time in which they are exposed to the wind, they are more likely to experience a Tof shift than the adjacent transmission and reception paths UTa, UTb, UTc, and UTd.

[0099] The first condition assumes that a Tof shift occurs in the diagonal transmission / reception paths UTx and Uty, but not in the adjacent transmission / reception paths UTa, UTb, UTc, and UTd. Here, if the wind speed increases, a Tof shift occurs in the diagonal transmission / reception paths UTx and Uty, causing the wind speed calculated from the diagonal transmission / reception paths UTx and Uty to be calculated as extremely small. In other words, the wind speed calculated for the diagonal transmission / reception paths UTx and Uty deviates by more than two times from the wind speed calculated for the adjacent transmission / reception paths UTa, UTb, UTc, and UTd. Here, because a Tof shift does not occur in the adjacent transmission / reception paths UTa, UTb, UTc, and UTd, the wind speed is calculated correctly. This deviation is used as the first condition. If the first condition is met, the correct second wind speed is output. If the first condition is not met, the first wind speed, which has a higher accuracy, is output.

[0100] If the first condition is not met (step S13; NO), the measurement unit 200 outputs the first wind velocities Vx and Vy (step S14). The measurement unit 200 may output the wind speed V calculated using the first wind speed Vx and the first wind speed Vy. Note that "output" may mean displaying on a display unit, outputting audio by an audio output unit, or outputting to a processing device connected to the ultrasonic anemometer 100.

[0101] If the first condition is met (step S13; YES), the measurement unit 200 outputs the second wind velocities Va to Vd (step S15). The measurement unit 200 may output the wind speed V calculated using the second wind velocities Va to Vd.

[0102] [Actions and Effects of the Ultrasonic Anemometer 100 According to the Embodiment] The ultrasonic anemometer 100 according to this embodiment includes a first ultrasonic transceiver 31, a second ultrasonic transceiver 32 that is separated from the first ultrasonic transceiver 31 by a first distance D1 in the X-axis direction (first direction), and a third ultrasonic transceiver 33 that is separated from the first ultrasonic transceiver 31 by a second distance D2 that is shorter than the first distance D1 in a direction different from the X-axis direction, and calculates an ultrasonic anemometer value using the results of ultrasonic transmission and reception between the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32 and the results of ultrasonic transmission and reception between the first ultrasonic transceiver 31 and the third ultrasonic transceiver 33. The control circuit 210 calculates a first wind speed Vx using the results of ultrasonic transmission and reception between the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32, calculates a second wind speed Vd using the results of ultrasonic transmission and reception between the first ultrasonic transceiver 31 and the third ultrasonic transceiver 33, and outputs the first wind speed Vx when the difference between the first wind speed Vx and the second wind speed Vd satisfies a first condition, and outputs the second wind speed Vd when the difference between the first wind speed Vx and the second wind speed Vd does not satisfy the first condition. Note that the first wind speed may be the first wind speed Vy, and the second wind speed may be the second wind speeds Va, Vb, or Vc.

[0103] Such an ultrasonic anemometer 100 can change whether to output the first wind speed Vx or the second wind speed Vd depending on whether the first condition is met. This can improve the measurement accuracy of the ultrasonic anemometer 100. By changing the wind speed to be output depending on whether the first condition is met, it is possible to adopt either the first wind speed Vx or the second wind speed Vd, whichever is more accurate.

[0104] The ultrasonic anemometer 100 may further include a fourth ultrasonic transceiver 34 that faces the third ultrasonic transceiver 33 in the Y-axis direction (second direction) that intersects with the X-axis direction and is spaced a second distance D2 from the first ultrasonic transceiver 31.

[0105] The control circuit 210 may calculate first wind speeds Vx, Vy using the results of ultrasonic transmission and reception between the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32 and the results of ultrasonic transmission and reception between the third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34, and may calculate second wind speeds Va, Vb, Vc using the results of ultrasonic transmission and reception between the first ultrasonic transceiver 31 and the third ultrasonic transceiver 33, the results of ultrasonic transmission and reception between the first ultrasonic transceiver 31 and the fourth ultrasonic transceiver 34, the results of ultrasonic transmission and reception between the second ultrasonic transceiver 32 and the third ultrasonic transceiver 333, and the results of ultrasonic transmission and reception between the second ultrasonic transceiver 32 and the fourth ultrasonic transceiver 34.

[0106] The ultrasonic anemometer 100 further includes a top plate 11 on which a first ultrasonic transceiver 31, a second ultrasonic transceiver 32, a third ultrasonic transceiver 33, and a fourth ultrasonic transceiver 34 are mounted, a reflecting plate (bottom plate) 21 facing the top plate 11 in the Z-axis direction (third direction), and a plurality of support columns 13 extending from the reflecting plate 21 in the Z-axis direction and supporting the top plate 11. When viewed in the Z-axis direction, the plurality of support columns 13 are arranged at positions that do not overlap with an imaginary first line connecting the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32, and an imaginary second line connecting the third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34.

[0107] In the ultrasonic anemometer 100 having this configuration, the multiple support pillars 13 are not arranged on the ultrasonic transmission / reception path between the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32. Similarly, the multiple support pillars 13 are not arranged on the ultrasonic transmission / reception path between the third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34. In the ultrasonic anemometer 100, it is possible to prevent the multiple support pillars 13 from being arranged on the ultrasonic transmission / reception path between the multiple ultrasonic transceivers 30. As a result, the ultrasonic anemometer 100 can accurately measure wind direction and wind speed by arranging the support pillars 13 so as not to affect the flow of the fluid to be measured.

[0108] In the ultrasonic anemometer 100, ultrasonic transmission and reception paths can be formed on the X-axis and Y-axis, and the X-axis component Vx and Y-axis component Vy of the wind speed V can be directly extracted, allowing for accurate calculation of the wind speed V. Furthermore, in the ultrasonic anemometer 100, the distance between the first ultrasonic transceiver 31 and the second ultrasonic transceiver 32, and the distance between the third ultrasonic transceiver 33 and the fourth ultrasonic transceiver 34 can be long, improving measurement accuracy.

[0109] Furthermore, the ultrasonic anemometer 100 can change the wind speed to be output depending on whether the first condition is met. The ultrasonic anemometer 100 can select and output an appropriate wind speed V from among the wind speed V based on the first wind speeds Vx and Vy and the wind speed V based on the second wind velocities Va to Vd, thereby avoiding a windless determination in a strong wind across phases. The ultrasonic anemometer 100 avoids adopting data that differs from the actual phase difference due to a phase shift of one cycle or more. Therefore, the ultrasonic anemometer 100 is prevented from calculating a wind speed that is significantly lower than the actual wind speed.

[0110] When there is a large difference between the wind speed V based on the first wind speeds Vx and Vy and the wind speed V based on the second wind speeds Va to Vd, the ultrasonic anemometer 100 can output the wind speed V based on the second wind speeds Va to Vd. This allows the ultrasonic anemometer 100 to expand the range over which wind speed V can be measured with high accuracy. The ultrasonic anemometer 100 can expand the range over which wind speed V can be measured with high accuracy even in strong winds.

[0111] It should be noted that the present invention is not limited to the configurations shown here, and other embodiments may be possible in which other components are combined with the configurations described in the above embodiments. In this regard, the present invention can be modified within the scope of the present invention, and can be appropriately determined depending on the application form.

[0112] In the above embodiment, an example is given of the ultrasonic anemometer 100 including a first ultrasonic transceiver 31, a second ultrasonic transceiver 32, a third ultrasonic transceiver 33, and a fourth ultrasonic transceiver 34, but the ultrasonic anemometer 100 may also include three or more ultrasonic transceivers 30.

[0113] Furthermore, in the above embodiment, an example is given in which the ultrasonic transceivers 30 are arranged at each corner of a square, but the arrangement of the ultrasonic transceivers 30 is not limited to this. The ultrasonic transceivers 30 may be arranged at the corners of a rhombus, a parallelogram, a trapezoid, or any other polygon.

[0114] In the above embodiment, the X-axis direction is the first direction and the Y-axis direction is the second direction, but the first and second directions are not limited to this. The Y-axis direction may be the first direction and the X-axis direction may be the second direction. The first and second directions may be other directions. Similarly, the direction in which multiple ultrasonic transceivers 30 are adjacent to each other is not limited to the above-mentioned direction. [Explanation of symbols]

[0115] 100: ultrasonic anemometer, 11: top plate, 12: first plane, 21: reflector, 22, 22B: second plane, 23: third plane, 30: multiple ultrasonic transmitter / receivers, 31: first ultrasonic transmitter / receiver, 32: second ultrasonic transmitter / receiver, 33: third ultrasonic transmitter / receiver, 34: fourth ultrasonic transmitter / receiver, X: X-axis direction (first direction), Y: Y-axis direction (second direction), Z: Z-axis direction (third direction).

Claims

1. a first ultrasonic transceiver; a second ultrasonic transceiver spaced a first distance in a first direction from the first ultrasonic transceiver; a third ultrasonic transceiver spaced a second distance from the first ultrasonic transceiver in a direction different from the first direction, the second distance being shorter than the first distance; a control circuit that performs arithmetic processing using a result of transmission and reception of ultrasonic waves between the first ultrasonic transceiver and the second ultrasonic transceiver and a result of transmission and reception of ultrasonic waves between the first ultrasonic transceiver and the third ultrasonic transceiver, The control circuit calculating a first wind speed using a result of transmission and reception of ultrasonic waves between the first ultrasonic transceiver and the second ultrasonic transceiver; calculating a second wind speed using a result of transmission and reception of ultrasonic waves between the first ultrasonic transceiver and the third ultrasonic transceiver; outputting the first wind speed when a difference between the first wind speed and the second wind speed does not satisfy a first condition; The ultrasonic anemometer outputs the second wind speed when a difference between the first wind speed and the second wind speed satisfies a first condition.

2. 2. The ultrasonic anemometer according to claim 1, wherein the first condition is that the second wind speed is at least twice as fast as the first wind speed.

3. The control circuit calculating the first wind speed using a first time when a first ultrasonic wave is transmitted from the first ultrasonic transceiver and received by the second ultrasonic transceiver, and a second time when a second ultrasonic wave is transmitted from the second ultrasonic transceiver and received by the first ultrasonic transceiver; 3. The ultrasonic anemometer according to claim 1, wherein the second wind speed is calculated using a third time when a third ultrasonic wave is transmitted from the first ultrasonic transceiver and received by the third ultrasonic transceiver, and a fourth time when a fourth ultrasonic wave is transmitted from the third ultrasonic transceiver and received by the first ultrasonic transceiver.

4. The control circuit the first time is a time closest to a fifth time among times when the amplitude of the first ultrasonic wave is 0 when the second ultrasonic transmitter / receiver receives the first ultrasonic wave, calculating the first wind speed by setting the second time as the time closest to the fifth time among the times when the amplitude of the second ultrasonic wave is 0 when the first ultrasonic transmitter / receiver receives the second ultrasonic wave; the third time is the time when the amplitude of the third ultrasonic wave is 0 when the third ultrasonic wave is received by the third ultrasonic wave transmitter / receiver, and the time closest to the fifth time is the third time; 4. The ultrasonic anemometer according to claim 3, wherein the second wind speed is calculated by using as the fourth time a time closest to the fifth time among times when the amplitude of the fourth ultrasonic wave is 0 when the first ultrasonic transmitter / receiver receives the fourth ultrasonic wave.

5. a fourth ultrasonic transceiver facing the third ultrasonic transceiver in a second direction intersecting the first direction and spaced the second distance from the first ultrasonic transceiver; The control circuit A result of transmission and reception of ultrasonic waves between the first ultrasonic transceiver and the second ultrasonic transceiver; calculating the first wind speed using a result of transmission and reception of ultrasonic waves between the third ultrasonic transceiver and the fourth ultrasonic transceiver; A result of transmission and reception of ultrasonic waves between the first ultrasonic transceiver and the third ultrasonic transceiver; A result of transmitting and receiving ultrasonic waves between the first ultrasonic transceiver and the fourth ultrasonic transceiver; A result of transmission and reception of ultrasonic waves between the second ultrasonic transceiver and the third ultrasonic transceiver; 2. The ultrasonic anemometer according to claim 1, wherein the second wind speed is calculated using a result of transmission and reception of ultrasonic waves between the second ultrasonic transceiver and the fourth ultrasonic transceiver.

6. a top plate on which the first ultrasonic transceiver, the second ultrasonic transceiver, the third ultrasonic transceiver, and the fourth ultrasonic transceiver are mounted; a bottom plate facing the top plate in a third direction intersecting the first direction and the second direction; a plurality of support columns extending from the bottom plate in the third direction and supporting the top plate; 6. The ultrasonic anemometer according to claim 5, wherein, when viewed in the third direction, the plurality of support columns are arranged at positions that do not overlap with a first imaginary line connecting the first ultrasonic transceiver and the second ultrasonic transceiver, and a second imaginary line connecting the third ultrasonic transceiver and the fourth ultrasonic transceiver.

7. A wind speed measurement method for measuring wind speed using an ultrasonic anemometer including a first ultrasonic transceiver, a second ultrasonic transceiver spaced a first distance in a first direction from the first ultrasonic transceiver, and a third ultrasonic transceiver spaced a second distance from the first ultrasonic transceiver in a direction different from the first direction, the second distance being shorter than the first distance, receiving the ultrasonic waves transmitted from the first ultrasonic transceiver with the second ultrasonic transceiver, and calculating a first wind speed using the transmission and reception results of the ultrasonic waves; receiving the ultrasonic waves transmitted from the first ultrasonic transceiver with the third ultrasonic transceiver, and calculating a second wind speed using the transmission and reception results of the ultrasonic waves; outputting the first wind speed when a difference between the first wind speed and the second wind speed does not satisfy a first condition; A wind speed measurement method that outputs the second wind speed when a difference between the first wind speed and the second wind speed satisfies a first condition.

Images