Powder and granular volume estimation device and powder and granular volume estimation method

Abstract

To provide a powder and granular material volume estimation device and a powder and granular material volume estimation method for accurately estimating the volume of powder and granular materials stored in a container without increasing the number of devices.SOLUTION: The powder and granular material volume estimation device has transmission and reception means located at the top of a container for transmitting a transmission wave in multiple azimuth directions that are different from each other towards the surfaces of the powder and granular materials and receiving multiple reflected waves from multiple reflection points on the surfaces to output a received signal, distance calculation means for calculating a distance to each of the multiple reflection points by processing the received signal, and granular material volume estimation means for estimating the volume of the powder and granular material on the basis of the distances and the azimuth directions.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a powder / granular material volume estimation device and a powder / granular material volume estimation method for estimating the volume of powder / granular material contained in a container. [Background technology]

[0002] Conventionally, methods for measuring the volume of liquid or powder contained in a container such as a tank have been proposed. For example, Patent Document 1 relates to a liquid level gauge for measuring the liquid level of the liquid in a tank. This liquid level gauge is a device that detects the liquid level in a tank without contacting the liquid, and is installed above the liquid level and has multiple wave transmission and reception sets (sensors) consisting of a wave transmitter and a wave receiver. The liquid level gauge calculates the liquid level (height from the tank bottom to the liquid level) based on the time from when the sensor transmits a wave to when it receives the wave reflected from the liquid surface and the propagation speed of the wave transmitted from the sensor, and displays the average value of multiple liquid level positions taking into account the fluctuation of the liquid surface on the display unit.

[0003] As a method for measuring the volume of powdery or granular material such as gravel or ready-mixed concrete in a tank, for example, as shown in FIG. 5, there is a method using level switches 101a-101d (FIG. 5(a)) and a method using horn-type radars 111a-111d, which are a type of non-contact sensor (FIG. 5(b)). In the former method, multiple level switches 101a-101d (four in FIG. 5(a)) are attached to the top of the tank 5, and the "presence" of powdery or granular material is detected based on the presence or absence of contact. In FIG. 5(a), only the level switch 101a that is in contact with the powdery or granular material 6 at contact point C detects "powder presence", and the other level switches 101b-101d that are not in contact with the powdery or granular material 6 detect "absence of powdery or granular material". In the latter method, multiple horn-type radars 111a to 111d (four in Figure 5(b)) are installed on the top of the tank 5, and waves are transmitted vertically downward from the antennas of the horn-type radars 111a to 111d. The reflected waves are received from multiple reflection points R1 to R4 on the surface of the powder or granular material 6, thereby measuring the distances between the reflection points and the horn-type radars (111a-R1, 111b-R2, 111c-R3, 111d-R4). The volume of the powder or granular material 6 in the tank 5 is calculated based on these distances. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-133310 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, powder and granular materials exhibit unique behaviors that are different from fluids such as liquids. For example, as shown in FIG. 4, when powder and granular materials 6 are dropped into the tank 5 from the inlet 7 of the tank 5, the powder and granular materials 6 accumulate in a mountain shape with a peak just below the inlet 7 and a valley just above the outlet 8. That is, the surface shape of the powder and granular materials 6 in the tank 5 is not horizontal, and the difference in height of the surface is larger than when the content is liquid. For example, even in the example shown in FIG. 4, the height of the surface of the powder and granular materials 6 near the inlet 7 is significantly different from the height of the surface of the powder and granular materials 6 near the outlet 8. Therefore, in order to measure the volume of the powder and granular materials 6 in the tank 5 with high accuracy, the method of averaging the values ​​of multiple liquid level positions as described in Patent Document 1 is insufficient, and the method of measuring the volume of the powder and granular materials 6 in the tank 5 by the method shown in FIG. 5(b) has a problem that as many horn-type radars as possible must be installed.

[0006] Therefore, an object of the present invention is to provide a powdered or granular material volume estimation device and a powdered or granular material volume estimation method that can accurately estimate the volume of powdered or granular material contained in a container without increasing the number of devices. [Means for solving the problem]

[0007] In order to solve the above problem, the invention described in claim 1 is a powdered or granular material volume estimation device for estimating the volume of powdered or granular material contained in a container, characterized in having: a transmitting / receiving means located at an upper part of the container, transmitting a transmission wave toward the surface of the powdered or granular material in a plurality of different azimuth directions, receiving a plurality of reflected waves from a plurality of reflection points on the surface, and outputting a received signal; a distance calculation means for calculating a distance to each of the plurality of reflection points by processing the received signal; and a powdered or granular material volume estimation means for estimating the volume of the powdered or granular material based on the distance and the azimuth direction.

[0008] The invention described in claim 2 is a powder / granular material volume estimation method for estimating the volume of powder / granular material contained in a container, comprising: a transmission / reception process for transmitting a transmission wave from an upper part of the container toward a surface of the powder / granular material in a plurality of different azimuth directions, receiving a plurality of reflected waves from a plurality of reflection points on the surface, and outputting a received signal; a distance calculation process for calculating a distance to each of the plurality of reflection points by processing the received signal; and a powder / granular material volume estimation process for estimating the volume of the powder / granular material based on the distance and the azimuth direction. Effect of the Invention

[0009] According to the inventions of claims 1 and 2, since a transmission wave is transmitted from one device in a plurality of different azimuth directions, the volume of powder or granular material in a container can be estimated with high accuracy without providing a plurality of devices, which simplifies the configuration and reduces costs. Moreover, by increasing the azimuth directions in which the transmission wave is transmitted, the accuracy of the volume estimation of the powder or granular material can be easily improved. Moreover, since it becomes possible to accurately grasp the timing for refilling the container with powder or granular material and the volume to be refilled, it becomes possible to easily store and manage the powder or granular material in the container. [Brief description of the drawings]

[0010] [Figure 1] 1 is a block diagram showing a schematic configuration of a powder / granular material volume estimation device according to an embodiment of the present invention; [Diagram 2]FIG. 2A illustrates the transmission of a transmission wave to the surface of a powder or granular material and the reception of a reflected wave by the device of FIG. 1, and FIGS. 2B and 2C illustrate a method for calculating the position of a reflection point on the surface of a powder or granular material from the distance to the reflection point and the azimuth direction of the transmission wave. [Diagram 3] 2 is a flowchart showing a procedure for estimating the volume of powder or granular material using the device of FIG. 1. [Figure 4] 10A and 10B are diagrams for explaining the behavior of powdered or granular material when the powdered or granular material is carried into a container. [Diagram 5] FIG. 1 is a diagram for explaining a conventional method for measuring the volume of powder or granular material. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the present invention will be described based on the illustrated embodiment.

[0012] Fig. 1 is a block diagram showing a schematic configuration of a powdered material volume estimation device according to an embodiment of the present invention. A radar device (powdered material volume estimation device) 1 is installed on top of a tank (container) 5, and includes a transmitting / receiving unit (transmitting / receiving means) 2, a distance calculation unit (distance calculation means) 3, and a powdered material volume estimation unit (powdered material volume estimation means) 4. Specific examples of powdered material include gravel, ready mixed concrete, grains, etc.

[0013] The radar device 1 is one embodiment of the powder / granular material volume estimation device of the present invention, and is a mechanism that is installed, for example, on top of a tank 5, transmits a transmission wave that is a radar signal and receives a reflected wave of the transmission wave to estimate the volume of the powder / granular material 6 contained in the tank 5, and specifically, may be a phase monopulse FMCW (Frequency Modulated Continuous Wave) radar.

[0014] In the FMCW method, a frequency-modulated continuous wave (specifically, radio waves) is transmitted as a transmission wave, and the reflected wave that is reflected off the surface of the powder or granular material 6 is received, outputting a received signal, and the distance between the radar device 1 and the surface of the powder or granular material 6 is calculated by processing the received signal.

[0015] FMCW radar is a continuous wave radar that performs frequency modulation over time, and generates and transmits a burst wave including multiple chirps. Each chirp included in the burst wave is generated by sweeping the frequency over time, so that the frequency changes linearly (specifically, increases / decreases) over time. The modulation width and modulation period of the chirp frequency (i.e., the repetition period of the chirp) may be adjusted as appropriate.

[0016] The radar device 1 is installed so that its transmitting / receiving unit 2 is located at the top of the tank 5. Specifically, the radar device 1 is preferably installed at a position where, when transmitting a transmission wave from the transmitting unit 21 to the surface of the powder or granular material 6, there is no area on the surface of the powder or granular material 6 where the transmission wave does not reach, or where the area where the transmission wave does not reach is minimized; for example, it is preferable to install the radar device 1 near the entrance 7 at the top of the tank 5.

[0017] The transmitting section 21 of the transmitting / receiving unit 2 transmits transmission waves in a plurality of different azimuth directions toward the surface of the powder or granular material 6. The transmitting section 21 is configured as a mechanism including, for example, a voltage generator, a voltage controlled oscillator, and a transmitting antenna.

[0018] The voltage generator generates and outputs a control voltage that changes in a triangular (or sawtooth) waveform, with successive alternating sections on the time axis where the level gradually increases and sections where the level gradually decreases.

[0019] The voltage-controlled oscillator generates and outputs a transmission signal that changes in a triangular (or sawtooth) waveform in which modulation sections in which the frequency gradually increases and modulation sections in which the frequency gradually decreases on the time axis in response to a control voltage alternate continuously.

[0020] The transmitting antenna generates a transmission wave based on the transmission signal, and transmits the transmission wave toward the surface of the powder or granular material 8 contained in the tank 5.

[0021] The transmitter 21 generates radio waves (also called "millimeter waves") having a frequency of, for example, 79 GHz, 76 GHz, or 60 GHz, and radiates them via a transmitting antenna toward the surface of the powder or granular material 6. In the present invention, it is preferable to use radio waves in a high frequency band.

[0022] The receiving section 22 of the transmitting / receiving unit 2 receives a plurality of reflected waves from a plurality of reflecting points on the surface of the powder or granular material 6 and outputs a received signal. The receiving section 22 is configured as a mechanism including, for example, a receiving antenna, a mixer, and an A / D converter.

[0023] The receiving antenna receives a reflected wave that is the transmission wave transmitted from the transmitting antenna of the transmitting unit 21 and reflected back by the surface of the powder or granular material 6 contained in the tank 5, and converts the received reflected wave (received wave) into a received signal and outputs it.

[0024] The mixer mixes the radio waves (transmission signal) distributed and transmitted from the transmitter 21 with the radio waves (reception signal) output from the reception antenna to generate and output a differential signal (an analog signal).

[0025] The A / D converter performs sampling processing (analog-to-digital conversion processing) on ​​the differential signal output from the mixer using a predetermined sampling frequency, converts the differential signal into digital data, and outputs the digitized differential signal.

[0026] As shown in FIG. 2(a), the radar device 1 of the present invention is characterized in that the transmitter 21 transmits a transmission wave toward the surface of the powder or granular material 6 through a transmission antenna in a plurality of different azimuth angles. In this case, the transmission wave may be transmitted simultaneously in a plurality of different azimuth angles, or the transmission wave may be transmitted in a plurality of different azimuth angles by changing the azimuth angle direction for each transmission timing. In FIG. 2(a), the transmission wave is transmitted in 10 azimuth angles, but the number of azimuth angles for transmitting the transmission wave is preferably as large as possible in terms of increasing the estimation accuracy of the volume of the powder or granular material. In addition, it is preferable that the transmitter 21 uses digital beamforming when transmitting the transmission wave. By using digital beamforming, the transmission wave can be reliably directed in a desired azimuth angle direction without using a mechanical rotation mechanism.

[0027] As shown in Fig. 2(a), the radar device 1 of the present invention is characterized in that the receiver 22 receives a plurality of reflected waves from a plurality of reflection points on the surface of the powder or granular material 6 via the receiving antenna. In Fig. 2(a), the number of reflection points is 10, R1 to R10, but the more the number of reflection points, the more preferable it is in terms of increasing the estimation accuracy of the volume of the powder or granular material. When receiving the reflected waves, the receiver 22 preferably uses digital beamforming. By using digital beamforming, it becomes possible to more reliably receive a plurality of reflected waves from a plurality of reflection points in mutually different azimuth angle directions.

[0028] Here, the azimuth angle direction to the reflection point refers to the angle θRn (θRn≧0 or θRn≦0) obtained by assuming the beam direction of the vertically downward radar beam as 0 degrees, as shown in Fig. 2(b). As shown in Fig. 2(c), for example, the azimuth angle direction of reflection point R1 is negative (θRn<0), and the azimuth angle direction of reflection point R8 is positive (θRn>0).

[0029] The direction of digital beamforming may be two-dimensional or three-dimensional, but three-dimensional is preferable in terms of increasing the accuracy of estimating the volume of the powder or granular material 6. In addition, the method of digital beamforming is not particularly limited.

[0030] The transmitting / receiving unit 2 may include one transmitting antenna and one receiving antenna, or may include multiple transmitting and receiving antennas. In addition, the transmitting and receiving antennas may be phased array antennas that can change the direction of the signal by controlling the phase of the radio waves being transmitted and received.

[0031] Distance calculation unit 3 is composed of, for example, a CPU and a memory in which a program for causing this CPU to perform a specified operation is stored, and functions as distance calculation unit 3 when the CPU operates according to the program.

[0032] The distance calculation unit 3 processes the received signal to calculate the distance from the radar device 1 (receiving antenna) to each of the multiple reflection points (R1 to R10 in the example of FIG. 2(a)). The distance calculation method in the distance calculation unit 3 is not particularly limited in the present invention, and any known method can be used. For example, if the radar device 1 of the present invention is an FMCW type radar, the distance to each reflection point (R1 to R10 in the example of FIG. 2(a)) can be calculated based on the frequency difference between the transmission signal frequency modulated at a constant period and the received signal of the wave reflected from the reflection points on the surface of the powder or granular material 6 (R1 to R10 in the example of FIG. 2(a)).

[0033] The powder / granular material volume estimation unit 4 estimates the volume of the powder / granular material 6 based on the distances from the radar device 1 (receiving antenna) to each of the multiple reflection points (R1 to R10 in the example of FIG. 2(a)) obtained by the distance calculation unit 3 and the azimuth angles between the radar device 1 (receiving antenna) and each of the multiple reflection points (R1 to R10 in the example of FIG. 2(a)). The method of estimating the volume of the powder / granular material 6 in the powder / granular material volume estimation unit 4 is not particularly limited in the present invention, and any known method can be used. For example, as shown in FIG. 2(b), the vertical distance lRn from the radar device 1 (receiving antenna) to the reflection point Rn is calculated based on the distance from the radar device 1 (receiving antenna) to the reflection point Rn and the azimuth angle direction θRn between the radar device 1 (receiving antenna) and the reflection point Rn. The position of the reflection point Rn (the height from the bottom of the tank 5 to the reflection point Rn) is calculated by subtracting the vertical distance lRn from the height L0 from the bottom of the tank 5 to the radar device 1 (receiving antenna). This is multiplied by the cross-sectional area per reflection point Rn to calculate the volume of the powder or granular material at the reflection point Rn. This operation is performed for all of the multiple reflection points (R1 to R10 in the example of FIG. 2(a)) and the volumes of the powder or granular material 6 at each of the multiple reflection points (R1 to R10 in the example of FIG. 2(a)) are added up, whereby the volume of the powder or granular material 6 in the tank 5 can be estimated. As described above, the surface shape of the powder 6 in the tank 5 is not horizontal due to its characteristics, but changes in a complex manner, so the greater the number of reflection points, the higher the accuracy of estimating the volume of the powder 6. The obtained estimated volume of the powder 6 may be displayed on the display unit of the radar device 1 or an external display device.

[0034] Next, the operation of the above embodiment will be described with reference to the flow chart of Fig. 3. The radar device 1 transmits a transmission wave from the transmitting unit 21 toward the surface of the powder or granular material 6 contained in the tank 5 in a plurality of different azimuth angle directions (10 azimuth angle directions in the example of Fig. 2(a)) (step S1). The transmission wave transmitted from the transmitting unit 21 is reflected by a plurality of reflection points (R1 to R10 in the example of Fig. 2(a)) on the surface of the powder or granular material 6, and the receiving unit 22 receives a plurality of reflected waves from the plurality of reflection points, converts the received reflected waves into received signals, and outputs them (step S2).

[0035] The distance calculation unit 3 processes the received signal obtained in step S2, and calculates the distance from the radar device 1 (receiving antenna) to each of the multiple reflection points (R1 to R10 in the example of FIG. 2(a)) (step S3).

[0036] The powder / granular material volume estimation unit 4 estimates the volume of the powder / granular material 6 in the tank 5 based on the distance from the radar device 1 (receiving antenna) to each of the multiple reflection points (R1 to R10 in the example of Figure 2(a)) obtained in step S3 and the azimuth angle direction between the radar device 1 (receiving antenna) and the multiple reflection points (θRn in the example of Figure 2(b)) (step S4).

[0037] As described above, according to the radar device 1 of this embodiment, since a single device transmits transmission waves in a plurality of mutually different azimuth directions, the volume of the powder or granular material 6 in the tank 5 can be estimated with high accuracy without providing a plurality of devices, and the configuration can be simplified and costs can be reduced. Moreover, by increasing the azimuth directions in which the transmission waves are transmitted, the accuracy of the volume estimation of the powder or granular material 6 can be easily improved. Moreover, since the timing for refilling the tank 5 with the powder or granular material 6 and the refill volume can be accurately grasped, the storage and management of the powder or granular material 6 in the tank 5 can be facilitated.

[0038] Although the embodiment of the present invention has been described above, the specific configuration is not limited to the above embodiment, and even if the design is changed within the scope of the present invention, it is included in the present invention. For example, in the above embodiment, a radar device is used as an example, but the powder volume estimation device of the present invention is not limited to a radar device. For example, it may be a non-contact distance sensor that can send a transmission wave in a plurality of different azimuth angles. [Explanation of symbols]

[0039] 1. Radar device (powder volume estimation device) 2. Transmitting / receiving unit (transmitting / receiving means) 21 Transmitter 22 Receiving section 3. Distance calculation unit (distance calculation means) 4 Powder volume estimating section (powder volume estimating means) 5 Tank (container) 6 Powder 7 Loading entrance 8 Exit 101a~101d Level switch 111a~111d Horn type radar R1~R10 Reflection point C Contact point

Claims

1. A powder / granular material volume estimation device for estimating the volume of powder / granular material contained in a container, comprising: a transmitting / receiving means located at an upper portion of the container, for transmitting a transmission wave toward a surface of the powder or granular material in a plurality of mutually different azimuth angles, receiving a plurality of reflected waves from a plurality of reflection points on the surface, and outputting a received signal; a distance calculation means for calculating a distance to each of the plurality of reflection points by processing the received signal; a powder volume estimation means for estimating a volume of the powder based on the distance and the azimuth angle; A powder / granular material volume estimation device comprising:

2. A method for estimating the volume of powder or granular material contained in a container, comprising: a transmitting and receiving step of transmitting a transmission wave from an upper portion of the container toward a surface of the powder or granular material in a plurality of mutually different azimuth angle directions, receiving a plurality of reflected waves from a plurality of reflection points on the surface, and outputting a received signal; a distance calculation step of calculating a distance to each of the plurality of reflection points by processing the received signal; a powder / granule volume estimating step of estimating a volume of the powder / granule based on the distance and the azimuth angle direction; A powder / granular material volume estimation method comprising the steps of:

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