Remaining amount estimation system

Abstract

Provided is a remaining amount estimation system that is attached to a container (T) which contains contents (C) and that estimates the remaining amount of the contents (C), said remaining amount estimation system comprising a sensor unit (6) that measures the distance (df) to the contents (C) by measuring the time until a transmitted radio wave is reflected by a surface (F) of the contents (C) and received, and that outputs the measurement result information which indicates the measured distance, and a remaining amount estimation unit that estimates the remaining amount on the basis of the measurement result information. The remaining amount estimation unit estimates the remaining amount without use of a measured distance that, among measured distances indicated by the measurement result information, is less than or equal to a first threshold value (d1) which is set in advance in accordance with a specification of the container (T) and / or the sensor unit (6).

Description

Remaining amount estimation system

[0001] The present disclosure relates to a remaining capacity estimation system.

[0002] Patent Document 1 discloses an inventory notification system for managing the remaining amount of kerosene stored in an ordinary home, etc. The inventory notification system disclosed in Patent Document 1 includes an inventory detection means such as a pressure sensor, a transmitting terminal that transmits data on the remaining amount of kerosene detected by the inventory detection means by wireless or the like, a receiving terminal that receives the data on the remaining amount of kerosene transmitted from the transmitting terminal, and an inventory management device that stores the remaining amount data received from the receiving terminal and notifies the user of the remaining amount of kerosene, etc.

[0003] Patent Document 2 discloses an inventory estimation method for estimating the inventory amount in a storage tank that stores a solid, liquid, or a mixture thereof from the readings of a level meter such as an ultrasonic sensor. The inventory estimation method disclosed in Patent Document 2 includes a first step of conducting a model experiment to match the scale of a scale model of the storage tank to obtain the relationship between the readings of the level meter in the actual storage tank and the inventory amount, a second step of measuring the pile height of the stored material in the actual storage tank with the level meter, and a third step of estimating the inventory amount in the actual storage tank from the relationship between the readings of the level meter obtained in the actual storage tank and the inventory amount corresponding to the readings of the level meter in the actual storage tank obtained by the model experiment.

[0004] JP 2012-86941 A JP 2019-158854 A

[0005] In the techniques disclosed in Patent Document 1 and Patent Document 2, a sensor is used to estimate the remaining amount of the contained material (kerosene in Patent Document 1, and the stored material in Patent Document 2). Some sensors have a range in which they cannot detect accurately due to their sensitivity characteristics, etc., and depending on the sensor used, there is a problem in that the remaining amount of the contained material cannot be accurately estimated.

[0006] Therefore, there is a need for a remaining amount estimation system that can more accurately estimate the remaining amount of stored items.

[0007] The characteristic configuration of the remaining amount estimation system disclosed herein is a remaining amount estimation system that is attached to a container that holds an item and estimates the remaining amount of the item, and includes a sensor unit that measures the distance to the item by measuring the time it takes for a transmitted radio wave to be reflected off the surface of the item and received, and outputs measurement result information indicating the measured distance, and a remaining amount estimation unit that estimates the remaining amount based on the measurement result information, wherein the remaining amount estimation unit estimates the remaining amount without using any measured distance indicated by the measurement result information that is below a first allowable threshold that is preset in accordance with the specifications of the sensor unit and / or the container.

[0008] With this characteristic configuration, the remaining amount can be estimated without using a measurement distance equal to or less than the first allowable threshold that is preset according to the specifications of the sensor unit (for example, the area that cannot be accurately measured due to the sensitivity characteristics of the sensor unit) and the specifications of the container (for example, the area that cannot be accurately measured due to the specifications of the container size, shape, etc.). Therefore, the remaining amount of the contained item can be estimated more accurately.

[0009] In addition, the remaining amount estimation unit preferably determines whether the measured distance exceeds a predetermined second tolerance threshold based on a bottom distance indicating the distance between the sensor unit and the bottom surface of the container, and if it determines that the measured distance exceeds the second tolerance threshold, it preferably estimates that the remaining amount of the contained item is full.

[0010] When the container contains an item with a high dielectric constant compared to air, the measured distance to the bottom indicated by the measurement result information output from the sensor unit becomes larger than the actual bottom distance, and a value exceeding the second allowable threshold is output as the measured distance. By utilizing this phenomenon, if the measured distance exceeds the second allowable threshold set in advance based on the bottom distance, it is possible to determine that the remaining amount of the item is full, thereby enabling a more accurate estimation of the remaining amount of the item.

[0011] Preferably, the remaining amount estimation unit estimates that the remaining amount of the contained item is full when it determines that the measured distance is equal to or less than the first allowable threshold.

[0012] With this configuration, even if the reflected wave reflected from the bottom surface is attenuated depending on the size or type of the contents and is not received by the sensor unit, or is not detected (determined to be received) by the sensor unit, the remaining amount of the contents can be determined to be full, and the remaining amount of the contents can be estimated more accurately.

[0013] Furthermore, when the remaining capacity estimation unit determines that the measured distance is equal to or less than the second tolerance threshold, it preferably determines whether the measured distance is within a predetermined tolerance range for the bottom distance, and if it determines that the measured distance is within the tolerance range, it preferably estimates that the remaining capacity is empty.

[0014] With this configuration, by determining whether the measured distance is within a preset tolerance range for the bottom distance, it is possible to estimate that the container is empty, thereby enabling a more accurate estimation of the remaining amount of contents.

[0015] Preferably, when it is determined that the measured distance is not within the allowable range, the remaining capacity estimation unit estimates the remaining capacity based on the measured distance.

[0016] With this configuration, the remaining amount of the contents can be calculated when the contents are neither full nor empty, so the remaining amount of the contents can be estimated more accurately.

[0017] It is also preferable that the bottom distance is the measurement result information acquired by the sensor unit when the container does not contain any items.

[0018] With this configuration, the value actually measured and acquired by the sensor unit attached to the container can be set as the bottom distance, so the remaining amount of the contained item can be estimated more accurately.

[0019] Preferably, the bottom distance is container-specific information based on the specifications of the container.

[0020] With this configuration, the bottom distance can be set based on the container specifications, such as catalog values, eliminating the need to attach a sensor unit to the container to obtain (measure) the bottom distance, thereby avoiding complication of the work.

[0021] It is also preferable to further include a storage unit capable of storing the container-specific information.

[0022] With this configuration, for example, there is no need to perform the work of communicating with an external device that stores the container-specific information to obtain the container-specific information, thereby improving the responsiveness of the sensor unit.

[0023] It is also preferable to further include an input unit that allows input of the container-specific information.

[0024] With this configuration, for example, the work of attaching a sensor unit to a container to acquire (measure) the bottom distance becomes unnecessary, and the complexity of the work can be avoided.

[0025] It is also preferable that the contents are organic matter.

[0026] With this configuration, it is possible to estimate the remaining amount of various organic substances contained in the container.

[0027] 1 is a diagram showing an outline of a remaining amount estimation system according to an embodiment; FIG. 2 is a perspective view showing the configuration of a container and a remaining amount estimation device according to an embodiment; FIG. 3 is a cross-sectional view of a state in which a remaining amount estimation device is attached to the container shown in FIG. 2; FIG. 4 is an exploded perspective view of the remaining amount estimation device shown in FIG. 2; FIG. 5 is an exploded perspective view of the remaining amount estimation device shown in FIG. 2; FIG. 6 is a diagram showing an example of measurement result information according to an embodiment; FIG. 7 is a diagram showing an example of measurement result information according to an embodiment; FIG. 8 is a graph showing an example of the relationship between the depth of a contained item and the remaining amount according to an embodiment; FIG. 9 is a flowchart showing a remaining amount estimation process according to an embodiment; FIG. 10 is a diagram showing an outline of a remaining amount estimation system according to another embodiment.

[0028] Below, a description will be given of a remaining amount estimation system including a remaining amount estimation device according to an embodiment of the present disclosure. Note that the components of the embodiments described below can be combined with each other as long as they are not inconsistent with each other. Furthermore, the materials, shapes, dimensions, numbers, and arrangements of the components in each aspect of the embodiments described below are merely examples, and any design modifications are possible as long as the same functions can be achieved.

[0029] [Remaining Amount Estimation System] The schematic configuration of a remaining amount estimation system 200 including a remaining amount estimation device 100 will be described with reference to Figures 1 to 3. Figure 1 is a diagram showing the schematic configuration of the remaining amount estimation system 200. Figure 2 is a perspective view showing the configuration of a container T and the remaining amount estimation device 100, and Figure 3 is a cross-sectional view of the remaining amount estimation device 100 attached to the container T shown in Figure 2.

[0030] As shown in Figure 1, the remaining amount estimation system 200 includes a remaining amount estimation device 100 that estimates the remaining amount Ra of the contents C (see Figure 3) contained in a container T (see Figure 2), as well as a first external device 201 and a second external device 202 that are configured to be able to communicate with the remaining amount estimation device 100.

[0031] [First External Device] The first external device 201 is, for example, a monitoring device for monitoring the remaining amount Ra of the contained item C. The first external device 201 is capable of communication with the remaining amount estimation device 100 in accordance with a long-distance wireless standard corresponding to a first communication distance (1 km or more in this embodiment). In this embodiment, the first external device 201 is a server present on a network such as a cloud server provided by a telecommunications carrier or the like, and is configured to be able to communicate with the remaining amount estimation device 100 via a base station.

[0032] [Second External Device] The second external device 202 is, for example, a maintenance management device for performing maintenance on the remaining amount estimation device 100. The second external device 202 is capable of communication with the remaining amount estimation device 100 in accordance with a short-range wireless standard corresponding to a second communication distance (up to 300 m in this embodiment). In this embodiment, the second external device 202 is an information processing terminal such as a mobile phone or a smartphone, and is configured to be able to communicate with the remaining amount estimation device 100 within a distance (range) within which the remaining amount estimation device 100 is visible.

[0033] 2 and 3, the container T has a container body T1, a cylindrical opening T2 protruding from the container body T1, and a lid T3 closing the opening T2. In this embodiment, the container T is a kerosene tank, and the contents C are kerosene.

[0034] The container body T1 includes a bottom surface T11, a side surface T12, and a top surface T13, and the bottom surface T11, the side surface T12, and the top surface T13 form a storage space TS (see FIG. 3) for storing (storing) the contents C. The opening T2 connects the storage space TS to the outside of the container T. The opening T2 is disposed on the top surface T13 opposite the bottom surface T11 of the container body T1, and protrudes in a direction away from the bottom surface T11 (a direction perpendicular to the top surface T13) relative to the top surface T13. The opening T2 has, for example, a diameter (inner diameter) of 50 mm or more and 65 mm or less, and has a smaller area than the top surface T13 when viewed from a direction perpendicular to the top surface T13. The top surface T13 has, for example, a diameter of 5000 mm. ２ Over 7000mm ２ The following is the result.

[0035] The contents C are supplied to the storage space TS through the opening T2 and stored in the storage space TS (stored in the storage space TS). The opening T2 is configured to allow a lid T3 to be attached, and is closed by attaching the lid T3. The lid T3 contains resin as a material, and the remaining amount estimation device 100 is attached to the lid T3. In other words, the remaining amount estimation device 100 is disposed opposite the bottom surface T11 of the container main body T1.

[0036] In the following, when the lid portion T3 to which the remaining amount estimation device 100 is attached is attached to the opening T2, the direction from the remaining amount estimation device 100 toward the bottom surface T11 of the container main body portion T1 will be referred to as the "vertical direction Z," the side of the vertical direction Z on which the bottom surface T11 is located will be referred to as the "lower side Z1," and the opposite side (the side on which the remaining amount estimation device 100 is located) will be referred to as the "upper side Z2."

[0037] [Remaining Amount Estimating Device] The remaining amount estimating device 100 estimates the remaining amount Ra of the contents C contained in the container T. FIGS.

[0038] 4 and 5, the remaining capacity estimation device 100 includes a housing 1, a lens unit 2, a board 3, a power supply unit 4 (see FIG. 5), a control unit 5 (see FIG. 5), a sensor unit 6 (see FIG. 4), a memory unit 7 (see FIG. 5), a remaining capacity estimation unit 8 (see FIG. 5), and a communication unit 9 (see FIG. 5). The communication unit 9 is an example of an input unit.

[0039] [Housing] The housing 1 is insulating and contains resin as a material. As shown in FIG. 3 , the housing 1 is disposed so as to cover the lid T3 of the container T and is held by the lid T3. The housing 1 and the lid T3 form a storage space 1S (see FIG. 4 ) that houses the lens unit 2, the substrate 3, the power supply unit 4, the control unit 5, the sensor unit 6, the memory unit 7, the remaining amount estimation unit 8, and the communication unit 9. In this embodiment, the storage space 1S is configured to be watertight. The storage space 1S is configured to be watertight, for example, by applying a sealant such as adhesive or grease to the gap between the lid T3 and the housing 1.

[0040] 4 and 5 improves the sensitivity of the sensor unit 6. The lens unit 2 has a lens 21 (convex lens) and a lens holder 22 that holds the lens 21. The lens 21 is a resin lens made of resin, and is held by the lens holder 22 so that the lens 21 faces the sensor unit 6 with the container T side raised. In this embodiment, the lens holder 22 is configured separately from the lid T3 and is supported by the lid T3 of the container T. Note that the lens holder 22 may be configured integrally with the lid T3.

[0041] [Circuit Board] The circuit board 3 is mounted with a power supply unit 4, a control unit 5, a sensor unit 6, a memory unit 7, a remaining capacity estimation unit 8, and a communication unit 9. In this embodiment, the sensor unit 6 is arranged on one first surface 31 of the circuit board 3 (see FIG. 4), and the power supply unit 4, the control unit 5, the memory unit 7, the remaining capacity estimation unit 8, and the communication unit 9 are arranged on the other second surface 32 of the circuit board 3 (see FIG. 5). The circuit board 3 is housed in the housing 1 so that the side on which the sensor unit 6 is arranged (first surface 31) faces the lower side Z1, and is attached to the lid T3 (see FIG. 3).

[0042] [Power Supply Unit] The power supply unit 4 supplies power to each unit of the remaining capacity estimation device 100. The power supply unit 4 has a power supply circuit 41 and a battery unit 42. The power supply circuit 41 converts (DC-AC conversion and / or voltage conversion) the power from the battery unit 42 and supplies the converted power to each unit of the remaining capacity estimation device 100 (the control unit 5, the sensor unit 6, the memory unit 7, the remaining capacity estimation unit 8, and the communication unit 9). In this embodiment, the battery unit 42 is a built-in primary battery, but the battery unit 42 may also be a secondary battery or a combination of a self-power-generating device and a secondary battery.

[0043] [Control Unit] The control unit 5 can control the operation of each unit of the remaining capacity estimation device 100. The control unit 5 can control the power supply to the power supply unit 4 and communication with the communication unit 9. The control unit 5 can also update firmware for devices such as the sensor unit 6 and the communication unit 9. The control unit 5 is configured with a microcontroller or the like equipped with a processor.

[0044] [Sensor Unit] The sensor unit 6 outputs estimation source information C1 used to estimate the remaining amount Ra of the contents C contained in the container T. In this embodiment, the sensor unit 6 is a distance measuring sensor (millimeter wave sensor for distance measurement) that uses radio waves (millimeter waves) to measure the distance to a measurement target. As shown in FIG. 3 , the sensor unit 6 measures the time it takes for radio waves transmitted from a transmitter included in the sensor unit 6 to be reflected by a reflective surface and received by a receiver (light receiving element) included in the sensor unit 6. In other words, the sensor unit 6 is a ToF (Time Of Flight) level sensor that can measure the distance to the contents C without contacting the contents C. Note that the transmission and reception efficiency of radio waves from the sensor unit 6 is improved by the radio waves passing through the lens 21 of the lens unit 2.

[0045] The reflective surfaces include the boundary surface F of the contained item C (the liquid surface of kerosene in this embodiment), the bottom surface T11 of the container T, and the wall surfaces constituting the opening T2 of the container T. In this embodiment, the relative dielectric constant εr of the contained item C is "2", which is larger than the relative dielectric constant εr of air, "1 (approximately 1)". In other words, the relative dielectric constant εr changes at the boundary surface F of the contained item C. It is preferable that the gas (air) present between the sensor unit 6 and the boundary surface F does not contain water vapor.

[0046] The sensor unit 6 outputs measurement result information C2 (see FIGS. 6A to 6C) indicating the distance to the measurement target based on the measured time.

[0047] Each of Figures 6A to 6C shows an example of measurement result information C2 output by sensor unit 6. In each of Figures 6A to 6C, the vertical axis indicates the reflection intensity Ri of the radio wave transmitted from sensor unit 6, and the horizontal axis indicates the measured distance ds between sensor unit 6 and the reflective surface. Figure 6A shows an example of measurement result information C2 output by sensor unit 6 when the remaining amount Ra of contained items C is estimated to be full. Figure 6B shows an example of measurement result information C2 output by sensor unit 6 when the remaining amount Ra of contained items C is estimated to be empty. Figure 6C shows an example of measurement result information C2 output by sensor unit 6 when the remaining amount Ra of contained items C is estimated to be a specific amount that is neither full nor empty. Note that "full amount" refers to, for example, the remaining amount Ra of contained items C when the volume of contained items C contained in storage space TS is equal to the storage capacity of container T (hereinafter referred to as "storage capacity"). "Empty" refers to, for example, the remaining amount Ra of the contents C when the capacity of the contents C stored in the storage space TS is "0." However, the capacity of the contents C when estimated to be full and the capacity of the contents C when estimated to be empty can be adjusted by an administrator of the remaining amount estimation device 100, and an allowable range, which will be described later, can also be set. When the contents C are at the remaining amount Ra of the storage capacity, it is preferable to set the full state of the contents C so that there is an air area of ​​about several centimeters between the lid portion T3 and the contents C.

[0048] As shown in Figures 6A to 6C, in this embodiment, two thresholds (a first threshold d1 and a second threshold d2) are set for the measurement distance ds (the distance between the sensor unit 6 and the reflective surface that reflects the radio waves) indicated by the measurement result information C2 output by the sensor unit 6.

[0049] [First Threshold] The first threshold d1 is a threshold that is set in advance according to the specifications of the sensor unit 6 and / or the container T. More specifically, the first threshold d1 is set in advance by an administrator or the like based on the sensitivity characteristics of the sensor unit 6 (the distance from the sensor unit 6 at which distance measurement by the sensor unit 6 becomes unstable), the shape of the container T (e.g., the shape of the opening T2), the size of the container T (e.g., the size of the opening T2), etc. In this embodiment, the distance between the first dividing line L1 shown in FIG. 3 and the sensor unit 6 is set as the first threshold d1, taking into consideration the sensitivity characteristics of the sensor unit 6 (whether the distance is at which the sensor unit 6 can output an accurate value).

[0050] The first division line L1 is set, for example, as a boundary between an area including the measured distance ds output by the sensor unit 6 that receives radio waves reflected from the wall surfaces (other than the boundary surface F and the bottom surface T11) that constitute the opening T2 and an area including the measured distance ds output by the sensor unit 6 that receives radio waves reflected from the wall surfaces that constitute the opening T2 but are not the wall surfaces that constitute the opening T2, but are the boundary surface F or the bottom surface T11, taking into consideration the sensitivity characteristics of the sensor unit 6. In this embodiment, the first division line L1 is set to the boundary surface F (liquid level) of the contained items C when the remaining amount Ra of the contained items C is estimated to be full (considered to be full) taking into consideration the sensitivity characteristics of the sensor unit 6. In the example shown in FIG. 3 , the first division line L1 is set at a position a predetermined distance away from the bottom end of the opening T2. However, the first division line L1 may also be set at the bottom end of the opening T2.

[0051] [Second Threshold Value] The second threshold value d2 is set in advance based on the distance (actual distance) between the second dividing line L2 and the sensor unit 6. In this embodiment, the second dividing line L2 is set in advance by an administrator or the like, so that the second dividing line L2 is the bottom surface T11 of the container T. In other words, the second threshold value d2 is set to a value equal to the value indicating the actual distance between the sensor unit 6 and the bottom surface T11 (hereinafter referred to as "bottom distance dt").

[0052] [Acceptable Range] In this embodiment, an acceptable range (first acceptable range R1 and second acceptable range R2) is set for each of the first dividing line L1 and the second dividing line L2. The upper limit of the first acceptable range R1 (a value larger than the first dividing line L1) is an example of a first acceptable threshold, and the upper limit of the second acceptable range R2 (a value larger than the second dividing line L2) is an example of a second acceptable threshold. The second acceptable range R2 is also an example of an acceptable range.

[0053] The first allowable range R1 and the second allowable range R2 are set, for example, so as to straddle the first dividing line L1 and the second dividing line L2, respectively. More specifically, the first allowable range R1 and the second allowable range R2 are set to values ​​(values ​​corresponding to several centimeters to several tens of centimeters) that include the ranges above Z2 (the sensor unit 6 side) and below Z1 (the bottom surface T11 side) of each of the first dividing line L1 and the second dividing line L2. The values ​​set as the first allowable range R1 and the second allowable range R2 are determined in advance by an administrator or the like.

[0054] By setting the first allowable range R1 and the second allowable range R2, it is possible to absorb individual differences in the characteristics of the sensor unit 6 (sensor IC), and to provide a margin for estimating the remaining amount Ra. For example, by setting the first allowable range R1, it is possible to accommodate variations in the sensitivity characteristics of the sensor unit 6. Furthermore, for example, by setting the second allowable range R2, it is possible to estimate (regard as empty) the remaining amount Ra of the contained items C when the remaining amount Ra of the contained items C is extremely small.

[0055] The second allowable range R2 is set to a value that exceeds the measurement distance ds indicated by the measurement result information C2 output from the sensor unit 6 when the actual remaining amount Ra of the contents C is full (a value that includes the third measurement result information C23 described below in the measurement result information C2).

[0056] An example of a method for determining the value set as the second allowable range R2 will be described below with reference to equations (1) and (2).

[0057] As a premise, the measured distance ds output from the sensor unit 6 is proportional to the 1 / 2 power of the relative dielectric constant εr of the medium (contained item C) through which the radio waves pass relative to the actual distance dm of the medium (contained item C) through which the radio waves pass, and can therefore be calculated using the following formula (1): ds = dm × √εr Formula (1)

[0058] The measured distance ds output from the sensor unit 6 as the distance between the sensor unit 6 and the bottom surface T11 is calculated by the following equation (2), which is the sum of the contained item distance df (see Figure 3) between the sensor unit 6 and the contained item C and the depth dc1 of the contained item C (a value taking into account the relative dielectric constant εr: see Figure 3). ds = df + dc1 ... equation (2) For example, if the bottom distance dt (a value indicated by the container-specific information C3) indicating the actual distance between the sensor unit 6 and the bottom surface T11 is "100 cm," and the relative dielectric constant εr of air is "1" (approximately 1), and the actual distance (content distance df) between the contained item C, whose relative dielectric constant εr is "2," and the sensor unit 6 is 10 cm or less, and it is estimated (deemed) that the remaining amount Ra of the contained item C is full, the measured distance ds output from the sensor unit 6 as the distance between the sensor unit 6 and the bottom surface T11 is given by ds = 10 × √1 + (100 - 10) × √2 ≈ 137 by substituting the respective values ​​into the above equation (2). Therefore, in order to estimate that the remaining amount Ra of the contained item C is full when the actual distance (contained item distance df) between the contained item C having a relative dielectric constant εr of "2" and the sensor unit 6 is 10 cm or less, the value of the lower side Z1 with respect to the second dividing line L2 of the second allowable range R2 can be set to less than 37 cm (137 cm - 100 cm).

[0059] Furthermore, for example, if the remaining amount Ra of the contained item C is estimated to be empty when the depth dc (actual distance) of the contained item C is 5 cm or less (the depth dc1 when taking the relative dielectric constant into account from equation (1) is 5 × √2), the measured distance ds can be calculated by substituting the respective values ​​into equation (2) above, as follows: ds = (100 - 5) × √1 + 5 × √2 ≈ 102. Therefore, in order to estimate the remaining amount Ra as empty when the depth dc (actual distance) of the contained item C is 5 cm or less, it is sufficient to set a value greater than 2 cm as the value of the lower side Z1 with respect to the second dividing line L2 of the second allowable range R2.

[0060] From the above, if the allowable range Z1 below the second dividing line L2 is set to a value between more than 2 cm and less than 37 cm, it is possible to estimate that the remaining amount Ra of the contained items C is full when the actual distance between the contained items C and the sensor unit 6 is 10 cm or less, and to accurately estimate that the remaining amount Ra of the contained items C is empty when the depth dc (actual distance) of the contained items C is 5 cm or less. Note that by increasing the value set as the second allowable range R2 below the second dividing line L2, it is possible to increase the actual remaining amount Ra of the contained items C when it is estimated that the remaining amount Ra of the contained items C is empty.

[0061] 6A to 6C, the region below the upper limit of the first allowable range R1 will be referred to as the "first region A1," the region above the upper limit of the first allowable range R1 and below the upper limit of the second allowable range R2 will be referred to as the "second region A2," and the region above the upper limit of the second allowable range R2 will be referred to as the "third region A3." Furthermore, of the measurement result information C2 output from the sensor unit 6, the measurement result information C2 included in the first region A1 will be referred to as "first measurement result information C21," the measurement result information C2 included in the second region A2 will be referred to as "second measurement result information C22," and the measurement result information C2 included in the third region A3 will be referred to as "third measurement result information C23."

[0062] The sensor unit 6 outputs measurement result information C2 including at least one of first measurement result information C21, second measurement result information C22, and third measurement result information C23. The first measurement result information C21 may be output by the sensor unit 6 receiving radio waves reflected off the wall surface of the opening T2. In other words, the measured distance ds indicated by the first measurement result information C21 appearing in the first area A1 may not accurately represent the distance between the sensor unit 6 and the contained item C and is therefore not suitable for estimating the remaining amount Ra of the contained item C. Therefore, the measured distance ds indicated by the first measurement result information C21 (the measured distance ds included in the first area A1) is not used to estimate the remaining amount Ra of the contained item C. This prevents a decrease in the accuracy of the sensor unit 6.

[0063] The second measurement result information C22 can be output, for example, by the sensor unit 6 that receives radio waves reflected from the boundary surface F (liquid surface) or the bottom surface T11 of the container T. In other words, the second measurement result information C22 that appears in the second area A2 indicates the distance between the sensor unit 6 and the contained item C or the bottom surface T11, and is suitable for estimating the remaining amount Ra of the contained item C. Therefore, the measured distance ds indicated by the second measurement result information C22 (the measured distance ds included in the second area A2) is used for the remaining amount Ra of the contained item C.

[0064] The third measurement result information C23 is the measurement result information C2 that is output due to a change in the propagation speed of the radio waves (a change in the distance measurement amount) caused by the remaining contained item C. In detail, when the contained item C having a higher relative dielectric constant εr than air remains in the container T, the third measurement result information C23 can be output by the sensor unit 6 that receives the radio waves reflected from the bottom surface T11 of the container T as a reflection surface.

[0065] For example, when radio waves are propagated when the contents C are full, the radio waves are propagated only through the contents C (without passing through the air). In contrast, when radio waves are propagated when the contents C is "0" (empty), the radio waves are propagated only through the air (without passing through the contents C). As described above, the relative dielectric constant εr of the contents C, "2," is larger than the relative dielectric constant εr of air, "1." Therefore, the measured distance ds (apparent distance) to the bottom surface T11 of the container T indicated by the measurement result information C2 output from the sensor unit 6 is larger than the bottom distance dt, which is the actual distance, and a value exceeding the second threshold value d2 (i.e., third measurement result information C23) is output.

[0066] Specifically, the bottom distance dt between the sensor unit 6 and the bottom surface T11 is theoretically calculated as the sum of the distance from the sensor unit 6 to the boundary surface F of the contained item C and the depth dc of the contained item C. However, as described above, if a contained item C with a relative dielectric constant εr greater than "1" remains, the measured distance ds indicated by the measurement result information C2 output from the sensor unit 6 indicates a value greater than the actual bottom distance dt. That is, the depth dc1 (measured distance ds) of the contained item C calculated based on the measurement result information C2 output from the sensor unit 6 is greater than the actual depth dc of the contained item C. Unless multiple media with different relative dielectric constants εr are mixed as the contained item C, the second measurement result information C22 is considered to be a single value. Therefore, the third measurement result information C23, which indicates a distance (value) greater than the second measurement result information C22, is assumed to indicate the distance between the sensor unit 6 and the reflective surface (bottom surface T11) when the bottom surface T11 is the reflective surface. In other words, the measured distance ds indicated by the third measurement result information C23 appearing in the third area A3 does not indicate the distance between the sensor unit 6 and the contained item C, and is not suitable for estimating the remaining amount Ra (specific value) of the contained item C. Therefore, the measured distance ds indicated by the third measurement result information C23 (the measured distance ds included in the third area A3) is not used for estimating the remaining amount Ra (specific value) of the contained item C. Note that there may be cases where the third measurement result information C23 is not output due to the sensitivity characteristics of the sensor unit 6 (sensor IC), such as the measurement limit distance, the size of the container T, the relative dielectric constant εr of the contained item C, etc. However, since the third measurement result information C23 is not used for estimating the remaining amount Ra of the contained item C, there is no effect on the accuracy of the estimation of the remaining amount Ra of the contained item C.

[0067] 4 and 5 is configured with a non-volatile semiconductor memory, etc. The memory 7 is configured to be able to store container-specific information C3 based on the specifications of the container T to which the remaining amount estimation device 100 is attached, and estimation-related information C4 related to the estimation of the remaining amount Ra of the contents C stored in the container T. The memory 7 also stores information indicating the first threshold value d1, the second threshold value d2, the first allowable range R1, and the second allowable range R2.

[0068] [Container-Specific Information] The container-specific information C3 is information relating to specifications (size) specific to the container T. The container-specific information C3 includes information indicating the bottom distance dt between the sensor unit 6 fixed to the lid portion T3 and the bottom surface T11 of the container T. In this embodiment, the container-specific information C3 is acquired by measurement using the sensor unit 6 attached to the lid portion T3 when the container T does not contain any contents C (i.e., when the remaining amount Ra of the contents C is empty). However, the container-specific information C3 may be set based on the specifications (catalog values) of the container T, or may be set to a value obtained by actual measurement using a tape measure or the like.

[0069] [Estimated Related Information] The estimated related information C4 is information indicating the relationship between the measurement result information C2 output from the sensor unit 6 and the remaining amount Ra of the contained items C (see FIG. 7). FIG. 7 is a graph showing an example of the relationship between the depth dc of the contained items C and the remaining amount Ra of the contained items C, where the horizontal axis in FIG. 7 indicates the depth dc of the contained items C and the vertical axis indicates the remaining amount Ra of the contained items C. Note that the depth dc of the contained items C indicates the actual distance between the boundary surface F of the contained items C (the side of the sensor unit 6 (upper side Z2) shown in FIG. 3) and the bottom surface T11 of the container T.

[0070] The remaining amount estimation unit 8 includes a processor such as a CPU (Central Processing Unit). The remaining amount estimation unit 8 estimates the remaining amount Ra of the contained items C based on the measurement result information C2 output from the sensor unit 6 and the information stored in the memory unit 7 (container-specific information C3 and estimation-related information C4).

[0071] In this embodiment, the remaining amount estimation unit 8 estimates the remaining amount Ra of the contained item C by utilizing the fact that the propagation speed of the radio wave changes (the measured distance changes) depending on the relative dielectric constant εr of the contained item C. In detail, as described above, the remaining amount Ra of the contained item C is estimated by utilizing the fact that the measured distance ds output by the sensor unit 6 that receives the reflected wave reflected by the bottom surface T11 of the container T is larger than the actual bottom distance dt (the actual distance between the sensor unit 6 and the bottom surface T11).

[0072] 6A to 6C, the remaining amount estimating unit 8 estimates the remaining amount Ra without using the measured distances ds included in the first area A1 (measured distances ds equal to or less than the upper limit of the first allowable range R1) among the measured distances ds output by the sensor unit 6. In this embodiment, the remaining amount estimating unit 8 estimates the remaining amount Ra of the contained items C by determining whether the measured distance ds is included in the second area A2 (an area exceeding the upper limit of the first allowable range R1 and equal to or less than the upper limit of the second allowable range R2). Note that the remaining amount estimating unit 8 may determine that the remaining amount Ra of the contained items C is full if the measured distance ds indicated by the measurement result information C2 (second measurement result information C22) is equal to or less than the first allowable range R1.

[0073] When the remaining amount estimation unit 8 determines that the measured distance ds is not included in the second area A2, it determines whether the measured distance ds exceeds the upper limit of the second allowable range R2, and if it determines that the measured distance ds exceeds the upper limit of the second allowable range R2, it estimates that the remaining amount Ra of the contained items C is full.

[0074] When the remaining amount estimation unit 8 determines that the measured distance ds output by the sensor unit 6 is within the second area A2 (the measured distance ds exceeds the upper limit of the first allowable range R1 and is equal to or less than the upper limit of the second allowable range R2), it determines whether the measured distance ds is within the second allowable range R2 (between the lower limit and the upper limit of the second allowable range R2), and if it determines that the measured distance ds is within the second allowable range R2 (i.e., the measured distance ds is a value close to the distance between the sensor unit 6 and the bottom surface T11), it estimates that the remaining amount Ra of the contained items C is "0" (empty).On the other hand, if it determines that the measured distance ds is not within the second allowable range R2 (i.e., the measured distance ds is a value far from the distance between the sensor unit 6 and the bottom surface T11), it calculates the remaining amount Ra of the contained items C based on the measured distance ds.

[0075] [Calculation of remaining amount] When the remaining amount Ra of the contained items C is full, the remaining amount estimation unit 8 outputs remaining amount result information C5 indicating, for example, a value preset as the remaining amount Ra (the capacity of the contained items C when estimated to be full), and when the remaining amount Ra is empty, it outputs remaining amount result information C5 indicating "0". Furthermore, when the remaining amount Ra of the contained items C is neither full nor empty, the remaining amount estimation unit 8 calculates the remaining amount Ra of the contained items C and outputs remaining amount result information C5 indicating the calculation result. Note that, hereinafter, the process of calculating the remaining amount Ra may be referred to as the "remaining amount estimation process".

[0076] [Communication Unit] The communication unit 9 is capable of transmitting and receiving data indicating the remaining amount result information C5 output from the remaining amount estimation unit 8. The communication unit 9 has an antenna (not shown). The antenna may be, for example, an antenna member mounted on the substrate 3, a pattern antenna formed on the surface of the substrate 3, or an antenna built into a communication IC mounted on the substrate 3, or may be connected to an antenna member arranged in the accommodation space 1S by a communication wire or the like.

[0077] The communication unit 9 has a first communication unit 91 and a second communication unit 92 that have different communication distances (communication standards). The container-specific information C3 stored in the memory unit 7 can be input to the memory unit 7 of the remaining amount estimation device 100 via the first communication unit 91 or the second communication unit 92.

[0078] The first communication unit 91 is capable of communication in accordance with a long-distance wireless standard. The first communication unit 91 is configured with a communication device that complies with the long-distance wireless standard. In this embodiment, the first communication unit 91 is configured with a communication device that complies with LPWA (Low Power Wide Area). Note that the first communication unit 91 may also be a communication device that complies with 5G, LTE, or the like.

[0079] The first communication unit 91 is configured to be able to transmit remaining amount result information C5 estimated by the remaining amount estimation unit 8 to the first external device 201 described with reference to FIG. 1 . In other words, the first external device 201 is configured to be able to receive remaining amount result information C5 output from the remaining amount estimation unit 8. The first external device 201 has a first external communication unit (not shown) that is capable of communication using the same communication standard as the first communication unit 91, and is capable of communication with the first communication unit 91 in accordance with a long-distance wireless standard. This makes it possible to remotely monitor the remaining amount Ra of the container T output from the remaining amount estimation device 100. By monitoring the remaining amount Ra, it becomes possible for the contents C replenishment service system to replenish the contents C into the container T at the appropriate time.

[0080] The second communication unit 92 is capable of communication in accordance with a short-range wireless standard. The second communication unit 92 is configured with a communication device that complies with a short-range wireless standard. In this embodiment, the second communication unit 92 is configured with a communication device that complies with BLE (Bluetooth Low Energy). Note that the second communication unit 92 may also be a device that complies with standards other than BLE, such as Bluetooth (registered trademark), Wi-Fi, Private LoRa, Z-Wave, ZigBee (registered trademark), Thread, or Matter.

[0081] The second communication unit 92 receives control data for the remaining battery level estimation device 100 (control unit 5) from the second external device 202 described with reference to Fig. 1. In other words, the second external device 202 is configured to be able to transmit control data for the remaining battery level estimation device 100. The second external device 202 has a second external communication unit (not shown) that is capable of communication using the same communication standard as the second communication unit 92, and is capable of communication with the second communication unit 92 in accordance with a short-range wireless standard (for example, P-to-P wireless communication with the remaining battery level estimation device 100).

[0082] [Remaining Amount Estimation Process] Next, the remaining amount estimation process (remaining amount estimation method) performed by the remaining amount estimation unit 8 will be described with reference to Fig. 8. Fig. 8 is a flowchart showing the remaining amount estimation process. The remaining amount estimation process is performed, for example, at a predetermined (scheduled) frequency (for example, every hour). However, the remaining amount estimation process may also be performed in response to an instruction from an operator who estimates the remaining amount Ra of the contained items C.

[0083] 8, when execution is instructed at a preset timing or by an operator, the sensor unit 6 measures the distance to the reflective surface by transmitting radio waves from the transmitter, receives the radio waves, and outputs measurement result information C2 (step S101). When the remaining amount estimation unit 8 acquires the measurement result information C2 from the sensor unit 6 (step S103), it determines whether the measurement result information C2 includes second measurement result information C22 other than the first measurement result information C21 (step S105). That is, the remaining amount estimation unit 8 determines whether the measured distance ds indicated by the measurement result information C2 exceeds the upper limit of the first allowable range R1 and is equal to or smaller than the upper limit of the second allowable range R2.

[0084] When the remaining amount estimation unit 8 determines that the measurement result information C2 does not include the second measurement result information C22 (the measured distance ds is less than the upper limit of the first tolerance range R1 or exceeds the upper limit of the second tolerance range R2) (step S105; No), it estimates that the remaining amount Ra of the contained item C is full (step S107) and proceeds to step S115.

[0085] On the other hand, when the remaining amount estimation unit 8 determines that the measurement result information C2 includes second measurement result information C22 other than the first measurement result information C21 (the measured distance ds exceeds the upper limit of the first allowable range R1 and is equal to or less than the upper limit of the second allowable range R2) (step S105; Yes), it determines whether the measured distance ds is included in the second allowable range R2 (i.e., whether it is equal to or greater than the lower limit of the second allowable range R2) (step S109).

[0086] If the remaining amount estimation unit 8 determines that the measured distance ds is within the second allowable range R2 (step S109; Yes), it estimates that the remaining amount Ra is empty (remaining amount Ra "0") (step S111) and proceeds to step S115.

[0087] On the other hand, if the remaining amount estimation unit 8 determines that the measured distance ds is not included in the second allowable range R2 (step S109; No), the remaining amount estimation unit 8 obtains the remaining amount Ra of the contained item C by calculating it based on the measurement result information C2 estimated by the sensor unit 6 and the measurement result information C2 stored in the memory unit 7 (step S113), and proceeds to step S115.

[0088] For example, if the value indicated by the container-specific information C3 (the bottom distance dt between the sensor unit 6 and the bottom surface T11) is "100 cm" and the item distance df between the sensor unit 6 and the item C having a relative dielectric constant εr of "2" is "50 cm," the depth dc (actual distance) of the item C is calculated as 100-50=50 cm. The remaining amount estimation unit 8 calculates the remaining amount Ra of the item C based on the calculated depth dc (actual distance) of the item C and the estimation-related information C4. For example, as shown in the graph in FIG. 7, when the depth dc (actual distance) of the item C is "50 cm," the remaining amount estimation unit 8 calculates the remaining amount Ra of the item C as "100 L." Note that the remaining amount estimation unit 8 may calculate the remaining amount Ra using a value within the second allowable range R2 (a value shifted to the lower side Z1 or the upper side Z2).

[0089] Next, in step S115, the remaining amount estimation unit 8 outputs remaining amount result information C5 indicating the remaining amount Ra of the contained item C. In this embodiment, the remaining amount result information C5 is transmitted to the first external device 201 via the first communication unit 91. This completes the remaining amount estimation process.

[0090] Effects of the embodiment The remaining capacity estimating device 100 configured as above provides the following effects.

[0091] (1) According to the above embodiment, the measurement distance ds equal to or less than the upper limit of the first allowable range R1, which is preset according to the specifications of the sensor unit 6 (the area that cannot be accurately measured due to the sensitivity characteristics of the sensor unit 6, etc.) and the specifications of the container T (the area that cannot be accurately measured due to the specifications of the container T (particularly the size of the opening T2) of the container T, the shape of the opening T2 of the container T, etc.), is not used to estimate the remaining amount Ra. Therefore, the remaining amount Ra of the contained items C can be estimated more accurately.

[0092] (2) When there is a remaining amount Ra of the contained items C whose relative dielectric constant εr is large relative to air, the measured distance ds to the bottom surface T11 indicated by the measurement result information C2 output from the sensor unit 6 becomes larger than the actual bottom distance dt, and a value exceeding the upper limit of the second allowable range R2 is output as the measured distance ds. By utilizing this phenomenon, when the measured distance ds exceeds the upper limit of the second allowable range R2 that is preset based on the bottom distance dt, it is possible to determine that the remaining amount Ra of the contained items C is full, and it is possible to more accurately estimate the remaining amount Ra of the contained items C.

[0093] (3) Even if the reflected wave reflected by the bottom surface T11 is attenuated and not received by the sensor unit 6 due to the size or type of the contained item C, or is not detected (determined to have been received) by the sensor unit 6, the remaining amount Ra of the contained item C can be determined to be full, and the remaining amount Ra of the contained item C can be estimated more accurately.

[0094] (4) According to the above embodiment, by determining whether the measured distance ds is included in the second allowable range R2 preset based on the bottom distance dt indicating the distance between the sensor unit 6 and the bottom surface T11 of the container T, the remaining amount Ra can be estimated as empty, and the remaining amount Ra of the contained items C can be estimated more accurately. Furthermore, by adjusting the second allowable range R2, it is possible to estimate (regard) the remaining amount Ra as empty when it is small. Alternatively, by adjusting the first allowable range R1, it is possible to estimate (regard) the remaining amount as full even when there is a margin for storage capacity.

[0095] (5) According to the above embodiment, the remaining amount Ra of the contents C is calculated when the contents C is neither full nor empty, so the remaining amount Ra of the contents C can be estimated more accurately.

[0096] (6) According to the above embodiment, the value actually measured and acquired by the sensor unit 6 attached to the container T can be set as the bottom distance dt, thereby enabling a more accurate estimation of the remaining amount Ra of the contained item C. In addition, it becomes possible to distinguish between the second measurement result information C22 and the third measurement result information C23.

[0097] (7) According to the above embodiment, the bottom distance dt can be set based on the specifications of the container T, such as catalog values. This eliminates the need for the work (command creation) of attaching the sensor unit 6 to the container T and obtaining (measuring) the bottom distance dt, thereby avoiding complication of the work.

[0098] (8) According to the above embodiment, for example, the work (command creation) of executing communication to acquire the container-specific information C3 between an external device (e.g., the first external device 201) that stores the container-specific information C3 is not required, thereby improving the responsiveness of the sensor unit 6.

[0099] (9) According to the above embodiment, for example, the work (command creation) of attaching the sensor unit 6 to the container T and acquiring (measuring) the bottom distance dt is not required, thereby avoiding the complexity of the work. Furthermore, it is possible to store the container-specific information C3 in the memory unit 7 via the communication unit 9 without disassembling the remaining amount estimation device 100 during the manufacturing process of the remaining amount estimation device 100, at the time of shipment, after shipment, after attachment to the container T, etc.

[0100] (10) According to the above embodiment, the remaining amount Ra of various organic substances as the contained item C can be estimated. Because millimeter waves are absorbed by water and water vapor, millimeter waves that are not reflected by the water surface but penetrate the water are absorbed by the water. Therefore, if the sensor unit 6 is a millimeter wave sensor, the sensor unit 6 cannot receive waves reflected from the bottom surface T11, and therefore cannot output the measured distance ds. Furthermore, because oxygen absorbs millimeter waves at frequencies around 60 GHz, oxygen is affected in the same way as water and water vapor when the radio wave frequency of the millimeter wave sensor used is around 60 GHz. However, if the contained item C is organic, the sensor unit 6 can output the measured distance ds.

[0101] Other Embodiments (1) In the above embodiment, the remaining amount estimation device 100 includes the control unit 5, the memory unit 7, the remaining amount estimation unit 8, and the communication unit 9. However, the memory unit 7 and the remaining amount estimation unit 8 may be included in a device different from the remaining amount estimation device 100 (for example, as shown in FIG. 9 , a first external device 201 that is different from the remaining amount estimation device 100 and is included in a device included in the remaining amount estimation system). The first external device 201 may include an external memory unit 201a that can store container-specific information C3 and an external remaining amount estimation unit 201b that can estimate the remaining amount Ra. Note that the memory unit 7 and the remaining amount estimation unit 8 may be included in both the remaining amount estimation device 100 and the first external device 201. In other words, the housing 1 included in the remaining amount estimation device 100 only needs to accommodate at least the lens unit 2, the board 3, the sensor unit 6, and the communication unit 9, and the power supply unit 4, the control unit 5, the memory unit 7, and the remaining amount estimation unit 8 may be accommodated in a housing different from the housing 1. This simplifies the configuration of the remaining capacity estimating device 100. As a result, the cost required for the remaining capacity estimating device 100 can be reduced.

[0102] (2) In the above embodiment, the case where the housing 1 is configured as a single unit has been described, but the housing 1 may be configured as a plurality of divided bodies. Furthermore, the number of boards 3 is not limited to one, and may be multiple.

[0103] (3) In the above embodiment, the storage space 1S is configured to be watertight by applying a sealant such as adhesive or grease to the gap between the lid portion T3 and the housing 1. However, the configuration for making the storage space 1S watertight is not particularly limited. For example, the storage space 1S may be configured to be watertight by disposing an O-ring between the lid portion T3 and the housing 1. Alternatively, the storage space 1S may be configured to be watertight by ultrasonically welding the lid portion T3 and the housing 1. Furthermore, a material that is gas-permeable but liquid-impermeable may be used as part of the lid portion T3. Furthermore, the housing 1 may be configured to be dustproof or explosion-proof. In other words, the housing 1 may be configured to be waterproof, dustproof, explosion-proof, or the like by injecting a sealant such as a potting material.

[0104] (4) A waterproof connector (not shown) may be attached to the housing 1 described in the above embodiment. This allows the antenna to be connected to the connector and placed outside the housing 1. Alternatively, the battery unit 42 can be connected to the connector and placed outside the housing 1. This allows components that occupy a large volume to be placed outside the housing 1. In other words, by attaching a waterproof connector to the housing 1, the remaining battery charge estimation device 100 can be made smaller while maintaining the watertightness of the storage space 1S of the housing 1.

[0105] (5) In the above embodiment, the case where the contained item C is kerosene has been described, but the contained item C is not limited to kerosene, and may be any substance that has a relative dielectric constant εr of "approximately 1" or more (preferably "2" or more) relative to air and can be contained in the container T, for example, an organic substance (organic solvent). Furthermore, the contained item C is not limited to a liquid, and may be a solid or a mixture of a liquid and a solid. However, it is preferable that the contained item C does not contain air. The container T is changed appropriately depending on the contained item C to be contained.

[0106] (6) In the above embodiment, the first allowable range R1 is set to straddle the first dividing line L1, but the first allowable range R1 does not have to be set to straddle the first dividing line L1 (it may be set to straddle only one of the upper side Z2 (sensor unit 6 side) and the lower side Z1 (bottom surface T11 side)). The same applies to the second allowable range R2.

[0107] (7) In the above embodiment, the first allowable range R1 is set for the first dividing line L1, but the first allowable range R1 does not have to be set. The same applies to the second allowable range R2.

[0108] The present disclosure can be used in a remaining amount estimation system.

[0109] 6: Sensor unit 7: Memory unit 8: Remaining amount estimation unit 9: Communication unit (input unit) 200: Remaining amount estimation system C: Contents C2: Measurement result information C3: Container-specific information R2: Second allowable range (allowable range) Ra: Remaining amount T: Container T11: Bottom surface ds: Measurement distance dt: Bottom distance

Claims

1. A remaining amount estimation system that is attached to a container in which an item is stored and estimates the remaining amount of the item, comprising: a sensor unit that measures the distance to the item by measuring the time it takes for a transmitted radio wave to be reflected by the surface of the item and be received back, and outputs measurement result information indicating the measured distance; and a remaining amount estimation unit that estimates the remaining amount based on the measurement result information, wherein the remaining amount estimation unit estimates the remaining amount without using any measured distance indicated by the measurement result information that is below a first allowable threshold that is preset in accordance with the specifications of the sensor unit and / or the container.

2. The remaining amount estimation system of claim 1, wherein the remaining amount estimation unit determines whether the measured distance exceeds a predetermined second tolerance threshold based on a bottom distance indicating the distance between the sensor unit and the bottom surface of the container, and if it determines that the measured distance exceeds the second tolerance threshold, estimates that the remaining amount of the contained item is full.

3. The remaining amount estimation system according to claim 1, wherein the remaining amount estimation unit estimates that the remaining amount of the contained item is full when it determines that the measured distance is equal to or less than the first allowable threshold.

4. The remaining capacity estimation system of claim 2, wherein when the remaining capacity estimation unit determines that the measured distance is equal to or less than the second tolerance threshold, it determines whether the measured distance is within a preset tolerance range for the bottom distance, and if it determines that the measured distance is within the tolerance range, it estimates that the remaining capacity is empty.

5. The remaining capacity estimation system according to claim 4, wherein when the remaining capacity estimation unit determines that the measured distance is not within the allowable range, it estimates the remaining capacity based on the measured distance.

6. The remaining amount estimation system according to claim 2, wherein the bottom distance is the measurement result information acquired by the sensor unit when no item is contained.

7. The remaining amount estimation system according to claim 2, wherein the bottom distance is container-specific information based on the specifications of the container.

8. The remaining amount estimation system according to claim 7, further comprising a memory unit capable of storing the container-specific information.

9. The remaining amount estimating system according to claim 8, further comprising an input unit capable of inputting the container-specific information.

10. A remaining amount estimation system as described in claim 1 or 2, wherein the contents are organic matter.

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