Sorting system and sorting method

Abstract

This provides a novel sorting method for selecting items to be sorted. [Solution] The first sorting system 1A includes a transport unit 20 that transports the objects to be sorted 3 so that they pass through a sound collection space 34, a sound collection unit 33 that collects sound when the objects to be sorted 3 come into contact with a metal member 31 surrounding the sound collection space 34 as they pass through the sound collection space 34, an acoustic analysis unit 40 that performs spectral analysis to decompose the sound collected by the sound collection unit 33 into frequency components, a sorting unit 50 that sorts the objects to be sorted 3 that have passed through the sound collection space 34, and a control device 60 having a control unit that controls the sorting unit 50 based on the frequency components of the first frequency band in the results of the spectral analysis.

Description

Technical Field

[0001] The present invention relates to a sorting system and a sorting method for sorting waste.

Background Art

[0002] In order to recycle waste, a technique for sorting an object to be sorted by utilizing differences in physical properties of materials constituting the object to be sorted is known. For example, Patent Document 1 discloses a technique for sorting natural rubber and polyethylene by utilizing differences in hardness (compressive strength or elastic modulus) depending on the material of the object to be sorted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the field related to waste recycling, development of new technologies for sorting waste is still desired.

Means for Solving the Problems

[0005] The sorting system for solving the above problems includes a conveying unit that conveys the object to be sorted so that the object to be sorted passes through a sound collecting space, a sound collecting unit that collects the sound when the object to be sorted contacts a member surrounding the sound collecting space when the object to be sorted passes through the sound collecting space, an acoustic analysis unit that performs spectral analysis to decompose the sound collected by the sound collecting unit into frequency components, a sorting unit that sorts the object to be sorted that has passed through the sound collecting space, and a control unit that controls the sorting unit based on the frequency components in a first frequency band in the result of the spectral analysis.

[0006] The sound produced when an object to be sorted comes into contact with the material surrounding the sound collection space varies depending on the hardness of the object. Therefore, by controlling the sorting unit based on the frequency components of a specific frequency band when the object to be sorted comes into contact with the material surrounding the sound collection space, it is possible to sort objects that tend to produce relatively large frequency components in that frequency band from objects that tend to produce relatively small frequency components.

[0007] In the sorting system described above, the control unit may control the sorting unit based on a determination result obtained from the spectral analysis, which determines whether the representative value of the frequency component in the first frequency band is greater than or equal to a threshold value. With the above configuration, by performing a determination process using a threshold value for the representative value of the frequency component in the first frequency band, it is possible to sort objects that tend to have relatively large frequency components in the first frequency band and objects that tend to have relatively small frequency components.

[0008] In the sorting system described above, the control unit may control the sorting unit based on the results of comparing the representative value of the frequency component in the first frequency band with the representative value of the frequency component in a second frequency band different from the first frequency band, as determined by the spectral analysis. With this configuration, objects to be sorted can be sorted based on the relative magnitudes of the frequency components in the first frequency band and the frequency components in the second frequency band. With this configuration, sorting can be performed effectively even when there is variation in the loudness of the sound when the objects to be sorted come into contact with the members surrounding the sound collection space.

[0009] In the sorting system described above, the object to be sorted is one of a plurality of objects to be sorted, and the plurality of objects to be sorted include a first object to be sorted containing plastic and a second object to be sorted containing rubber, and the control unit may control the sorting unit to sort the plurality of objects to be sorted into the first object to be sorted and the second object to be sorted based on the frequency components of the first frequency band in the results of the spectral analysis. The first object to be sorted containing plastic is harder than the second object to be sorted containing rubber. Therefore, the sound produced when the first object to be sorted comes into contact with the member surrounding the sound collection space is different from the sound produced when the second object to be sorted comes into contact with the member surrounding the sound collection space. Accordingly, in a system like this one, in which objects to be sorted are sorted based on how they make sound, the first object to be sorted containing plastic and the second object to be sorted containing rubber can be suitably sorted.

[0010] In the sorting system described above, the lower limit of the first frequency band may be 1000 Hz or higher. The first sorting target, which includes plastic, tends to have relatively larger frequency components than the second sorting target, which includes rubber, at 1000 Hz or higher. Therefore, materials with relatively large frequency components in the first frequency band of 1000 Hz or higher can be sorted as the first sorting target, and those with relatively small frequency components can be sorted as the second sorting target.

[0011] In the above sorting system, the member surrounding the sound collection space may have protrusions that extend toward the sound collection space. With this configuration, when the objects to be sorted pass through the sound collection space, the objects to be sorted come into contact with the protrusions, thereby generating sound effectively.

[0012] In the sorting system described above, the maximum length of the object to be sorted may be 20 mm or more. This system allows for the appropriate sorting of relatively large objects, such as those with a maximum length of 20 mm or more. Furthermore, sorting can be performed while the objects are still relatively large, thereby reducing the number of sorting cycles. In addition, sorting can be performed while the objects are still relatively large, which allows for the appropriate generation of sound when the objects come into contact with the components surrounding the sound collection space.

[0013] The sorting system comprises an upstream sorting system and a downstream sorting system that sorts the sorted objects selected by the upstream sorting system, wherein one of the upstream sorting system and the downstream sorting system comprises a transport unit, a sorting unit which is a first sorting unit, a sound collection unit, an acoustic analysis unit, and a control unit, and the other of the upstream sorting system and the downstream sorting system supports a plurality of objects taken out from a group of sorting objects including a first sorting object and a second sorting object which is softer than the first sorting object. The system comprises a holding portion and a second sorting portion that presses a plurality of needles against the plurality of objects placed on the support portion with a specific load, wherein the specific load is set such that the needles that come into contact with the first sorting object do not penetrate the first sorting object, and the needles that come into contact with the second sorting object penetrate the second sorting object, and the other system may include a buffer portion that, when any of the plurality of needles come into contact with the first sorting object, allows the needles that are not in contact with the first sorting object to be displaced toward the support portion. By combining the upstream sorting system and the downstream sorting system, sorting can be performed with greater accuracy.

[0014] The sorting system described above may include an upstream sorting system and a downstream sorting system that sorts the sorted objects sorted by the upstream sorting system, wherein one of the upstream sorting system and the downstream sorting system comprises a transport unit, a sorting unit which is a first sorting unit, a sound collection unit, an acoustic analysis unit, and a control unit, and the other of the upstream sorting system and the downstream sorting system may include a support unit on which a specific sorting object, which is either a first sorting object or a second sorting object which is softer than the first sorting object, is placed, a position information acquisition unit which acquires position information of the specific sorting object placed on the support unit, and a second sorting unit which, based on the position information acquired by the position information acquisition unit, presses a sorting needle against the specific sorting object placed on the support unit with a specific load.

[0015] The sorting system described above may include an upstream sorting system and a downstream sorting system that sorts the sorted objects selected by the upstream sorting system, wherein one of the upstream sorting system and the downstream sorting system includes a transport unit, a sound collection unit, an acoustic analysis unit, a sorting unit which is a first sorting unit, and a control unit which is a first control unit, and the other of the upstream sorting system and the downstream sorting system may include a charging unit that charges objects, a charge amount measuring unit that measures the amount of charge of the objects charged by the charging unit, a second sorting unit that sorts the objects, and a second control unit that controls the second sorting unit according to the measurement result of the charge amount.

[0016] A sorting method for solving the above problems includes: transporting objects to be sorted so that they pass through a sound collection space; collecting sound when the objects to be sorted come into contact with a member surrounding the sound collection space as they pass through the sound collection space; performing spectral analysis to decompose the collected sound into frequency components; and sorting the objects that have passed through the sound collection space based on the frequency components of the first frequency band in the results of the spectral analysis. [Effects of the Invention]

[0017] According to the present invention, a novel sorting method for sorting objects can be provided. [Brief explanation of the drawing]

[0018] [Figure 1] Figure 1 is a schematic diagram showing the overall configuration of the first sorting system. [Figure 2] Figure 2 is a block diagram of the control device included in the first sorting system. [Figure 3] Figure 3 is a graph showing the results of spectral analysis of the sound of plastic (polypropylene) measured in the first sorting system. [Figure 4]Figure 4 is a graph showing the results of spectral analysis of the sound of plastic (polyethylene) measured in the first sorting system. [Figure 5] Figure 5 is a graph showing the results of spectral analysis of the sound of plastic (ABS) measured in the first sorting system. [Figure 6] Figure 6 is a graph showing the results of spectral analysis of the sound of rubber measured in the first sorting system. [Figure 7] Figure 7 is a graph showing the results of spectral analysis of the sound of a mixture of rubber and resin measured in the first sorting system. [Figure 8] Figure 8 is a graph showing the results of spectral analysis of the sound of plastic (polypropylene) measured in the first sorting system. [Figure 9] Figure 9 is a graph showing the results of spectral analysis of the sound of rubber measured in the first sorting system. [Figure 10] Figure 10 is a diagram for explaining a sorting form combining a plurality of systems. [Figure 11] Figure 11 is a schematic diagram showing the overall configuration of the second sorting system. [Figure 12] Figure 12 is a block diagram of the control device included in the second sorting system. [Figure 13] Figure 13 is a schematic diagram showing a configuration example of the sorting unit of the second sorting system. [Figure 14] Figure 14 is a schematic diagram showing an operation example of the sorting unit of the second sorting system. [Figure 15] Figure 15 is a schematic diagram showing a configuration example of the sorting unit of the second sorting system. [Figure 16] Figure 16 is a schematic diagram showing a configuration example of the support unit of the second sorting system. [Figure 17] Figure 17 is a schematic diagram showing the configuration of the third sorting system. [Figure 18] Figure 18 is a block diagram of the control device included in the third sorting system. [Figure 19]Figure 19 is a schematic diagram showing the overall configuration of the fourth sorting system. [Figure 20] Figure 20 is a block diagram of the control device included in the fourth sorting system. [Figure 21] Figure 21 is a schematic diagram illustrating the charging tendency of materials. [Modes for carrying out the invention]

[0019] [First Embodiment] A first embodiment of the sorting system and sorting method will be described with reference to Figures 1 to 9. As shown in Figure 1, the first sorting system 1A, for example, in a plant for recycling waste such as end-of-life automobiles, end-of-life home appliances, and miscellaneous scrap, sorts multiple sorting targets 3 made of different materials according to the difference in the sound they make.

[0020] The first sorting system 1A comprises a storage unit 10 and a plurality of recovery units 11. The storage unit 10 stores a group of sorting targets 2 consisting of a plurality of sorting targets 3 before sorting by the first sorting system 1A. The group of sorting targets 2 includes a plurality of sorting targets 3 made of different materials. The recovery units 11 store the sorted sorting targets 3 by material.

[0021] As an example, the sorting target group 2 includes, as multiple sorting target objects 3 before sorting, a first sorting target object 3A containing plastic and a second sorting target object 3B containing rubber. Of the multiple recovery units 11, the recovery unit 11 that contains the first sorting target object 3A is designated as the first recovery unit 11A, and the recovery unit 11 that contains the second sorting target object 3B is designated as the second recovery unit 11B.

[0022] The first sorting target 3A is sorting target 3 whose main raw material is plastic, and is a material that can be reused as a heat source. The second sorting target 3B is sorting target 3 whose main raw material is rubber. Having a specific material as the main raw material means that it contains more than 50% by mass of that specific material.

[0023] The shape of the object to be sorted 3 is not particularly limited and can take any form, such as block-shaped, rod-shaped, or chip-shaped. Furthermore, it is preferable that the multiple objects to be sorted 3 included in the object to be sorted group 2 are pre-sorted to a predetermined size. The maximum length of the object to be sorted 3 is, for example, 20 mm or more and 200 mm or less, preferably 100 mm or more and 200 mm or less. The maximum length of the object to be sorted 3 refers to the maximum value that can be taken as the length of the line segment connecting any two points on the outer surface of the object to be sorted 3. Note that the maximum length of the object to be sorted 3 is not limited to 20 mm or more and 200 mm or less, and may be less than 20 mm or more than 200 mm.

[0024] The first sorting system 1A comprises a transport unit 20, a sound collection unit 30, an acoustic analysis unit 40, a sorting unit 50, and a control device 60. The transport unit 20 transports the sorting targets 3 from the storage unit 10 to the recovery unit 11. The operation of the transport unit 20 is controlled by the control device 60. The transport unit 20 is, for example, a conveyor, but it may also be other devices such as a robotic arm. The sorting targets 3 are arranged in the transport unit 20 so that sufficient distance is maintained between each other. In Figure 1, the transport path TR1 of the sorting targets 3 by the transport unit 20 is shown by a solid line or a dashed-dot arrow.

[0025] A sound collection unit 30 and a sorting unit 50 are arranged on the transport path TR1 from the storage unit 10 to the recovery unit 11. The transport unit 20 includes, for example, a first part 21, a second part 22, and a third part 23. The first part 21 transports the sorting target 3 from the storage unit 10 to the sound collection unit 30. After being transported to the sound collection unit 30, the sorting target 3 passes through the sound collection unit 30 and then falls toward the sorting unit 50.

[0026] The sorting unit 50 sorts the objects to be sorted 3 according to the sound they make when they pass through the sound collection unit 30. The objects to be sorted 3 are sorted by the sorting unit 50 into either the second part 22 or the third part 23 according to the sound they make when they pass through the sound collection unit 30, and then transported to the recovery unit 11 by either the second part 22 or the third part 23. The operation of the sorting unit 50 is controlled by the control device 60.

[0027] The sound collection unit 30 comprises a plate-shaped metal member 31, a sound-insulating member 32 surrounding the upper part of the metal member 31, and a sound collection section 33. The sound collection unit 30 is configured as a cylindrical shape with openings at the top and bottom by combining the metal member 31 and the sound-insulating member 32. The sound collection unit 30 includes a sound collection space 34 enclosed by the metal member 31 and the sound-insulating member 32.

[0028] The metal member 31 is configured in a slope shape. The metal member 31 is located below the sound collection space 34. The metal member 31 has a projection 31A that protrudes toward the sound collection space 34. The presence of the projection 31A on the metal member 31 makes it easier for sound to be produced when the object to be sorted 3 passes through the sound collection space 34.

[0029] The soundproofing member 32 prevents external noise from entering the sound collection space 34. The soundproofing member 32 is composed of, for example, a soundproofing board or soundproofing sheet made of any material, or a combination thereof. For example, the soundproofing member 32 has a load capacity of 200 kg / m 3 A soundproofing board with a density of 25 kg / m 3 It is constructed by combining it with a soundproofing sheet having a certain density.

[0030] The sound collection unit 33 is positioned inside the sound collection space 34. The sound collection unit 33 collects sound when the object to be sorted 3 comes into contact with the metal member 31 surrounding the sound collection space 34 as the object to be sorted 3 passes through the sound collection space 34. The sound collection unit 33 is, for example, a sound-collecting microphone that converts the collected sound into an electrical signal.

[0031] The sound collected by the sound collection unit 33 is transmitted as acoustic data to the acoustic analysis unit 40. The acoustic analysis unit 40 performs spectral analysis on the acoustic data transmitted from the sound collection unit 33 to decompose the sound collected by the sound collection unit 33 into frequency components. The acoustic analysis unit 40 transmits the results of the spectral analysis to the control device 60. The control device 60 controls the sorting unit 50 based on the results of the spectral analysis.

[0032] The sorting unit 50 sorts the objects to be sorted 3 by changing the transport path TR1 in accordance with the control signal from the control device 60. Specifically, the sorting unit 50 transports the objects to be sorted 3 to either the second section 22 or the third section 23 in accordance with the control signal from the control device 60 output based on the results of spectral analysis.

[0033] For example, the second part 22 and the third part 23 are arranged vertically. In this case, the sorting unit 50 includes a fall direction switching unit that switches the direction in which the falling objects to be sorted 3 fall. The fall direction switching unit switches between a first state and a second state in response to a control signal from the control device 60.

[0034] For example, if the object to be sorted 3 is the first object to be sorted 3A, the drop direction switching unit switches to the first state in accordance with the control signal from the control device 60. In the first state, the drop direction switching unit drops the first object to be sorted 3A to the second section 22 located at the lower level, as shown by the transport path TR1 indicated by the solid arrow. The second section 22 transports the first object to be sorted 3A to the first recovery unit 11A.

[0035] For example, if the object to be sorted 3 is the second object to be sorted 3B, the drop direction switching unit switches to the second state in accordance with the control signal from the control device 60. In the second state, the drop direction switching unit drops the second object to be sorted 3B onto the third section 23 located on the upper level, as shown by the transport path TR1 indicated by the dashed arrow. The third section 23 then transports the second object to be sorted 3B to the second retrieval section 11B.

[0036] The sorting method of the first sorting system 1A begins with the first part 21 of the transport unit 20 transporting the objects to be sorted 3 so that they pass through the sound collection space 34. Next, the sound collection unit 33 collects the sound as the objects to be sorted 3 pass through the sound collection space 34. Then, the acoustic analysis unit 40 performs spectral analysis to decompose the collected sound into frequency components. Finally, the control device 60 controls the sorting unit 50 to sort the objects 3 that have passed through the sound collection space 34 based on the results of the spectral analysis.

[0037] [Control device 60] As shown in Figure 2, the control device 60 is connected to the transport unit 20, the acoustic analysis unit 40, and the sorting unit 50. The control device 60 comprises a control unit 61, a storage unit 62, an input unit 63, an output unit 64, and a communication unit 65.

[0038] The control unit 61 is hardware for executing the instruction set described in the program. The control unit 61 is composed of an arithmetic unit, registers, peripheral circuits, etc. The control unit 61 is, for example, a processor such as a CPU or MPU.

[0039] The memory unit 62 includes volatile memory and non-volatile memory. The volatile memory temporarily stores programs, processing data, etc. The volatile memory is, for example, DRAM (Dynamic Random Access Memory). The non-volatile memory is, for example, flash memory, HDD (Hard Disk Drive), or other storage for saving data.

[0040] The input unit 63 is an input device for receiving operation input from an external source. The input unit 63 includes, for example, a pointing device such as a mouse and a keyboard. The output unit 64 is an output device for displaying information to the outside. The output unit 64 is, for example, a display panel such as a liquid crystal display panel or an organic EL panel. The input unit 63 and the output unit 64 may also be a touch panel, for example, which combines a touchpad as an input device for receiving user operations and a display panel as an output device for displaying images. The communication unit 65 is a communication device for inputting and outputting signals for communication with an external device.

[0041] The control unit 61 functions as a transport control unit 61A, a sorting control unit 61B, etc., by executing a sorting program. The sorting program is stored in the storage unit 62. The transport control unit 61A controls various operations of the transport unit 20, such as turning it on and off and adjusting the transport speed. The sorting control unit 61B controls the sorting operation of the sorting unit 50 based on the results of spectral analysis transmitted from the acoustic analysis unit 40.

[0042] [How different materials produce different sounds] Here, we will explain the differences in how each material produces sound when the sorting target 3 passes through the sound collection space 34. The sound produced when the sorting target 3 passes through the sound collection space 34 differs depending on the material. Specifically, when the first sorting target 3A, which contains plastic, passes through the sound collection space 34, sounds above 1000Hz are relatively more likely to be produced. Also, when the second sorting target 3B, which contains rubber, passes through the sound collection space 34, sounds above 1000Hz are relatively less likely to be produced.

[0043] Figures 3 to 9 show the results of spectral analysis when the sorting target object 3, made of plastic or rubber, passes through the sound collection space 34. In the spectral analysis results, the horizontal axis represents frequency on a logarithmic scale. The vertical axis represents the magnitude (unit: dB) of the frequency components contained in the sound. The frequency components contained in the sound refer to the sound pressure level of a specific frequency contained in the sound. The sound pressure level is given by 10 times the common logarithm of the value obtained by dividing the square of the target sound pressure by the square of the reference sound pressure. The reference sound pressure is 20 μPa. In the following, frequency components below 1000 Hz are referred to as low-frequency components, and frequency components above 1000 Hz are referred to as high-frequency components.

[0044] Figures 3 to 7 show the spectral analysis results of the sound when the object to be sorted 3 is slid on the metal member 31 so that it contacts the projection 31A. Figures 8 and 9 show the spectral analysis results of the sound when the object to be sorted 3 is dropped from a height of 100 mm to 200 mm onto the metal member 31 that does not have the projection 31A. In all cases, the inclination angle of the metal member 31 was set to 45 degrees relative to the horizontal.

[0045] Figure 3 shows the spectral analysis results when the first sorting target object 3A made of polypropylene passes through the sound collection space 34. Figure 4 shows the spectral analysis results when the first sorting target object 3A made of polyethylene passes through the sound collection space 34. Figure 5 shows the spectral analysis results when the first sorting target object 3A made of ABS passes through the sound collection space 34.

[0046] As shown in Figures 3-5, in the first sorting target material 3A, which includes plastics such as polypropylene, polyethylene, and ABS, it was confirmed that there was no significant difference when comparing the frequency components on the low-frequency side and the high-frequency side.

[0047] Figure 6 shows the spectral analysis results when the second sorting target object 3B, made of rubber, passes through the sound collection space 34. Figure 7 shows the spectral analysis results when the second sorting target object 3B, a mixture of rubber and resin in block form, passes through the sound collection space 34.

[0048] As shown in Figures 6 and 7, it was confirmed that in the second sorting target object 3B, which contains rubber, the high-frequency components were smaller compared to the low-frequency components. Therefore, it was confirmed that in the second sorting target object 3B, which contains rubber, the high-frequency components tend to be smaller compared to the first sorting target object 3A, which contains plastic.

[0049] Figure 8 shows the spectral analysis results when the first sorting target object 3A, made of polypropylene, is dropped toward the metal member 31 and passes through the sound collection space 34. Figure 9 shows the spectral analysis results when the second sorting target object 3B, made of rubber, is dropped toward the metal member 31 and passes through the sound collection space 34.

[0050] As shown in Figure 8, even when the first object to be sorted 3A was dropped toward the metal member 31, the same spectral analysis results were observed as when the first object to be sorted 3A came into contact with the projection 31A. Similarly, as shown in Figure 9, even when the second object to be sorted 3B was dropped toward the metal member 31, the same spectral analysis results were observed as when the second object to be sorted 3B came into contact with the projection 31A.

[0051] [Control method for sorting unit 50] The sorting control unit 61B controls the sorting unit 50 so that the first sorting target 3A and the second sorting target 3B are sorted based on the frequency components of the first frequency band in the spectral analysis of the sound when the sorting target 3 passes through the sound collection space 34.

[0052] For example, the first frequency band is a frequency band where both the upper and lower limits are 1000 Hz or higher. The lower limit of the first frequency band is more preferably 3000 Hz or higher, and even more preferably 6000 Hz or higher. The upper limit of the first frequency band is, as an example, 10000 Hz or lower.

[0053] For example, the sorting control unit 61B controls the operation of the sorting unit 50 based on pre-set judgment information and the results of spectral analysis transmitted from the acoustic analysis unit 40. The judgment information is, for example, information that associates judgment conditions for performing judgment processing using the results of spectral analysis with commands for sorting operations to the sorting unit 50 in cases where the results of spectral analysis satisfy the judgment conditions and cases where they do not. The judgment information is stored in the storage unit 62.

[0054] The sorting control unit 61B determines whether the spectral analysis results satisfy the judgment conditions, and then controls the sorting unit 50 to perform sorting operations according to the judgment results. For example, the judgment conditions are numerical ranges or thresholds for distinguishing between the spectral analysis results of the sound when the first sorting target object 3A passes through the sound collection space 34 and the spectral analysis results of the sound when the second sorting target object 3B passes through the sound collection space 34.

[0055] As an example of a method for controlling the sorting unit 50, the sorting control unit 61B may control the sorting unit 50 based on a determination result obtained by determining whether the representative value of the frequency component in the first frequency band is greater than or equal to a threshold value in the spectral analysis results transmitted from the acoustic analysis unit 40. The representative value is one of the mean, median, mode, or maximum value.

[0056] In the second sorting target object 3B, which contains rubber, the frequency components in the first frequency band tend to be smaller compared to the first sorting target object 3A, which contains plastic. Therefore, the threshold in this case should be smaller than the representative value of the frequency components in the first frequency band in the spectral analysis results of the first sorting target object 3A, and larger than the representative value of the frequency components in the first frequency band in the spectral analysis results of the second sorting target object 3B.

[0057] By setting the threshold as described above, if the object to be sorted 3 is the first object to be sorted 3A, the representative value of the frequency component in the first frequency band in the spectral analysis results transmitted from the acoustic analysis unit 40 will be greater than the threshold. Conversely, if the object to be sorted 3 is the second object to be sorted 3B, the representative value of the frequency component in the first frequency band in the spectral analysis results transmitted from the acoustic analysis unit 40 will be smaller than the threshold.

[0058] Therefore, if the determination result is that the representative value of the frequency components in the first frequency band is above the threshold, the sorting control unit 61B controls the sorting unit 50 to drop the sorting target object 3 (first sorting target object 3A) that has passed through the sound collection space 34 into the second section 22. Also, if the determination result is that the representative value of the frequency components in the first frequency band is below the threshold, the sorting control unit 61B controls the sorting unit 50 to drop the sorting target object 3 (second sorting target object 3B) that has passed through the sound collection space 34 into the third section 23.

[0059] As an alternative control method, the sorting control unit 61B may control the sorting unit 50 based on the results of a spectral analysis comparing representative values ​​of frequency components in the first frequency band with representative values ​​of frequency components in a second frequency band different from the first frequency band. For example, the second frequency band is a frequency band where both the upper and lower frequency limits are less than 1000 Hz.

[0060] For example, the sorting control unit 61B may control the sorting unit 50 based on a determination result obtained by determining whether the value obtained by subtracting the representative value of the frequency component of the first frequency band from the representative value of the frequency component of the second frequency band in the spectral analysis results in a threshold or greater.

[0061] In the first sorting target object 3A, which contains plastic, the frequency components do not differ significantly between the first and second frequency bands, whereas in the second sorting target object 3B, which contains rubber, the frequency components in the first frequency band are smaller compared to the frequency components in the second frequency band. Therefore, the threshold in this case should be greater than the difference in frequency components between the first and second frequency bands in the first sorting target object 3A, and smaller than the difference in frequency components between the first and second frequency bands in the second sorting target object 3B.

[0062] By setting the threshold as described above, if object 3 is the first object 3A, the result of the spectral analysis transmitted from the acoustic analysis unit 40 will be such that the value obtained by subtracting the representative value of the frequency component in the first frequency band from the representative value of the frequency component in the second frequency band is less than the threshold. If object 3 is the second object 3B, the result of the spectral analysis transmitted from the acoustic analysis unit 40 will be such that the value obtained by subtracting the representative value of the frequency component in the first frequency band from the representative value of the frequency component in the second frequency band is greater than or equal to the threshold.

[0063] Therefore, for example, if the result of subtracting the representative value of the frequency component of the first frequency band from the representative value of the frequency component of the second frequency band is less than the threshold, the sorting control unit 61B controls the sorting unit 50 to drop the object to be sorted 3 into the second section 22. If the result of subtracting the representative value of the frequency component of the first frequency band from the representative value of the frequency component of the second frequency band is greater than or equal to the threshold, the sorting control unit 61B controls the sorting unit 50 to drop the object to be sorted 3 into the third section 23.

[0064] As explained above, the control method of the sorting unit 50 by the sorting control unit 61B may be in a form that uses the frequency components of the first frequency band in the results of spectral analysis. The control method of the sorting unit 50 may include a determination process using a threshold value for the representative value of the frequency components of the first frequency band, or it may include a determination process using the result of comparing the representative value of the frequency components of the first frequency band with the representative value of the frequency components of the second frequency band.

[0065] [Effects of the First Embodiment] (1-1) The sound produced when the object to be sorted 3 comes into contact with the metal member 31 surrounding the sound collection space 34 varies depending on the hardness of the object to be sorted 3. Therefore, by controlling the sorting unit 50 based on the frequency components of a specific first frequency band when the object to be sorted 3 comes into contact with the metal member 31, it is possible to sort objects 3 that tend to have relatively large frequency components in the first frequency band and objects 3 that tend to have relatively small frequency components.

[0066] (1-2) An example of how the sorting control unit 61B controls the sorting unit 50 is to control the sorting unit 50 based on the determination result of a determination process using a threshold value for the magnitude (representative value) of the frequency components of the first frequency band. With this control method, the sorting unit 50 can be controlled so that sorting target objects 3 that tend to have relatively large frequency components of the first frequency band and sorting target objects 3 that tend to have relatively small frequency components are sorted.

[0067] (1-3) An example of how the sorting control unit 61B controls the sorting unit 50 is to control the sorting unit 50 based on the result of comparing the representative value of the frequency component of the first frequency band with the representative value of the frequency component of the second frequency band. With such a control method, the objects to be sorted 3 can be sorted based on the relative magnitudes of the frequency components of the first frequency band and the frequency components of the second frequency band. With this configuration, sorting can be performed effectively even if there is variation in the loudness of the sound when the objects to be sorted 3 come into contact with the metal member 31.

[0068] (1-4) The first sorting target object 3A, which contains plastic, is harder than the second sorting target object 3B, which contains rubber. Therefore, the sound produced when the first sorting target object 3A comes into contact with the metal member 31 is different from the sound produced when the second sorting target object 3B comes into contact with the metal member 31. Thus, if the sorting target objects 3 are sorted based on the sound produced, as in the first sorting system 1A, the first sorting target object 3A containing plastic and the second sorting target object 3B containing rubber can be suitably sorted.

[0069] (1-5) In the spectral analysis results, the lower limit of the first frequency band used by the sorting control unit 61B to control the sorting unit 50 is 1000 Hz or higher. The first sorting target object 3A, which contains plastic, tends to have relatively larger frequency components than the second sorting target object 3B, which contains rubber, at 1000 Hz or higher. Therefore, objects with relatively large frequency components in the first frequency band above 1000 Hz can be sorted as the first sorting target object 3A, and objects with relatively small frequency components can be sorted as the second sorting target object 3B.

[0070] (1-6) The metal member 31 is provided with a projection 31A that protrudes toward the sound collection space 34, so that when the object to be sorted 3 passes through the sound collection space 34, the object to be sorted 3 comes into contact with the projection 31A, thereby generating sound effectively.

[0071] (1-7) The first sorting system 1A can suitably sort even relatively large sorting targets 3, such as those with a maximum length of 20 mm or more. Furthermore, by sorting the sorting targets 3 while they are still relatively large, the number of sorting cycles required to sort multiple sorting targets 3 included in the sorting target group 2 can be reduced. In addition, by sorting the sorting targets 3 while they are still relatively large, sound can be suitably generated when the sorting targets 3 come into contact with the metal member 31.

[0072] [Example of modification of the first embodiment] The first embodiment described above can be implemented with the following modifications. The following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0073] In the sound collection unit 30, the member surrounding the sound collection space 34 is not limited to the metal member 31, but may be made of other materials that easily produce sound when the object to be sorted 3 comes into contact with it. Also, if the object to be sorted 3 is dropped from a predetermined height into the sound collection space 34, the metal member 31 does not need to have the protrusion 31A.

[0074] The first frequency band is not limited to 1000Hz or higher; it should be any frequency band that allows for the distinction between the sound produced by the first sorting target object 3A, which includes plastic, and the sound produced by the second sorting target object 3B, which includes rubber.

[0075] The first sorting system 1A can be applied not only to the sorting of the first sorting target object 3A, which contains plastic, and the second sorting target object 3B, which contains rubber, but also to the sorting of other sorting target objects 3 made of materials that produce different sounds. In this case, the first frequency band and the second frequency band should be set appropriately based on the sound produced by the material of the sorting target object 3.

[0076] The sorting target group 2 may include a third sorting target other than the first sorting target 3A which includes plastic and the second sorting target 3B which includes rubber. If the sound produced by the third sorting target is different from that of either the first sorting target 3A or the second sorting target 3B, the sorting unit 50 may sort the sorting target group 2 into three items: the first sorting target 3A, the second sorting target 3B, and the third sorting target. If the sound produced by the third sorting target is the same as that of either the first sorting target 3A or the second sorting target 3B, the third sorting target may first be sorted together with the first sorting target 3A or the second sorting target 3B, and then the third sorting target may be sorted by other sorting means.

[0077] The first sorting system 1A may have multiple sound collection spaces 34, each separated from the others. In this case, multiple objects to be sorted 3 can be sorted in parallel, making the sorting of objects 3 more efficient. In the above configuration, soundproofing measures should be taken in each sound collection space 34 to prevent sound from other sound collection spaces 34 from entering.

[0078] [Second to Fourth Embodiments] The second to fourth embodiments of the sorting system and sorting method will be described with reference to Figures 10 to 21.

[0079] As shown in Figure 10, the sorting systems of the second to fourth embodiments include an upstream sorting system S1 and a downstream sorting system S2. In the sorting systems of the second to fourth embodiments, the downstream sorting system S2 further sorts the sorted objects sorted by the upstream sorting system S1, thereby improving the sorting accuracy and expanding the range of types and shapes of materials that can be sorted.

[0080] One of the upstream sorting system S1 and the downstream sorting system S2 is the first sorting system 1A described in the first embodiment. The other of the upstream sorting system S1 and the downstream sorting system S2 is one of the systems described in the second to fourth embodiments below. Note that each system described in the second to fourth embodiments can also function as a standalone sorting system.

[0081] [Second Embodiment] A second embodiment of the sorting system and sorting method will be described with reference to Figures 11 to 16. The second sorting system 1B shown in Figure 11 is the other system when the first sorting system 1A in the first embodiment is one of the upstream sorting system S1 and the downstream sorting system S2. The second sorting system 1B sorts multiple objects 3 made of different materials according to their differences in hardness.

[0082] If the second sorting system 1B is the upstream sorting system S1, the second sorting system 1B sorts multiple objects 3 before they are sorted by the first sorting system 1A. In this case, the objects 3 sorted by the second sorting system 1B are sorted as post-sorted objects by the first sorting system 1A, which is the downstream sorting system S2. Also, if the second sorting system 1B is the downstream sorting system S2, the second sorting system 1B sorts multiple objects 3 that have been sorted by the first sorting system 1A as post-sorted objects.

[0083] The second sorting system 1B comprises a storage unit 110, a first recovery unit 111, and a second recovery unit 112. The storage unit 110 stores a group of sorting targets 2 consisting of multiple sorting targets 3 before sorting by the second sorting system 1B. The first recovery unit 111 contains the first sorting target 3A. The second recovery unit 112 contains the second sorting target 3B.

[0084] In the second sorting system 1B, the sorting target group 2 includes, as multiple sorting target objects 3 before sorting, a first sorting target object 3A containing plastic and a second sorting target object 3B containing wood or rubber. The second sorting target object 3B is softer than the first sorting target object 3A. The sorting target group 2 may include only the second sorting target object 3B containing wood, or only the second sorting target object 3B containing rubber, or both the second sorting target object 3B containing wood and the second sorting target object 3B containing rubber.

[0085] The second sorting system 1B comprises a transport unit 120, a sorting unit 130, and a control device 140. The transport unit 120 transports the sorting target 3 from the storage unit 110 to the first recovery unit 111 or the second recovery unit 112. The operation of the transport unit 120 is controlled by the control device 140. The transport unit 120 is, for example, a conveyor.

[0086] The transport unit 120 comprises, for example, a first part 121, a second part 122, a third part 123, and a fourth part 124. The first part 121 transports the sorting target 3 from the storage unit 110 to the second part 122. The second part 122 transports the sorting target 3 toward the third part 123. Of the sorting target 3, the second sorting target 3B is transported to the fourth part 124 by the sorting unit 130 while being transported by the second part 22. Therefore, of the sorting target 3, only the first sorting target 3A is transported to the third part 123 by the second part 122. The third part 123 transports the first sorting target 3A to the first recovery unit 111. The fourth section 124 transports the second sorting target material 3B, which has been transported from the second section 122 by the sorting section 130, to the second recovery section 112.

[0087] The second part 122 corresponds to a support part that supports the objects to be sorted 3 when the sorting unit 130 sorts the objects to be sorted 3. The second part 122 is provided with an inclined surface 122S that supports the objects to be sorted 3. As an example, the second part 122 conveys the objects to be sorted 3 in an oblique upward direction.

[0088] The sorting unit 130 is equipped with multiple needles 131 arranged in a direction perpendicular to the transport direction (the depth direction of the paper in Figure 11). The sorting unit 130 presses the multiple needles 131 against the object to be sorted 3 placed on the inclined surface 122S, along the direction normal to the inclined surface 122S.

[0089] The sorting unit 130 presses each of the multiple needles 131 against the object to be sorted 3 with a specific load. The specific load is set so that the needle 131 that comes into contact with the first object to be sorted 3A does not penetrate the first object to be sorted 3A, and the needle 131 that comes into contact with the second object to be sorted 3B penetrates the second object to be sorted 3B. In other words, when the sorting unit 130 presses the multiple needles 131 toward the object to be sorted 3, the multiple needles 131 do not penetrate the first object to be sorted 3A, which contains plastic, located in the second section 122, but only penetrate the second object to be sorted 3B, which contains wood or rubber.

[0090] The sorting section 130 includes a detachment section 132 for removing the second sorting target object 3B that has been impaled on the needle 131 from the needle 131. The detachment section 132 is located above the fourth section 124. The detachment section 132 is, for example, a plate-shaped member having a hole through which the needle 131 can be inserted. Alternatively, the detachment section 132 is two plate-shaped members spaced apart to allow the needle 131 to be inserted. When the sorting section 130 pulls up the multiple needles 131, it brings the second sorting target object 3B impaled on the needle 131 into contact with the detachment section 132, thereby removing the second sorting target object 3B from the needle 131. The second sorting target object 3B that has been removed from the needle 131 falls toward the fourth section 124.

[0091] The sorting method in the first sorting system 1A involves first transporting multiple objects to be sorted 3 from the storage section 110 through the first section 121 to the second section 122. The sorting section 130 then presses multiple needles 131 against the multiple objects to be sorted 3 that have reached the second section 122 with a specific load.

[0092] Of the multiple sorting targets 3 placed on the second section 122, the first sorting target 3A is hard and therefore does not get pierced by the multiple needles 131, and is transported to the third section 23 by the second section 22. The third section 123 transports the first sorting target 3A to the first recovery section 111.

[0093] Of the multiple sorting targets 3 placed on the second section 122, the second sorting target 3B becomes impaled on one of the multiple needles 131. The sorting unit 130 then pulls up the multiple needles 131 along the direction normal to the inclined surface 122S. As a result, the sorting unit 130 brings the second sorting target 3B, which is impaled on the needles 131, into contact with the detachment unit 132, causing the second sorting target 3B, which is impaled on the needles 131, to fall toward the fourth section 124. The fourth section 124 transports the second sorting target 3B to the second retrieval unit 112. In this manner, the sorting unit 130 sorts the first sorting target 3A and the second sorting target 3B.

[0094] [Control device 140] As shown in Figure 12, the control device 140 is connected to the transport unit 120 and the sorting unit 130. The control device 140 comprises a control unit 141, a storage unit 142, an input unit 143, an output unit 144, and a communication unit 145. The hardware configuration of the control device 140 can be the same as that of the control device 60 in the first embodiment.

[0095] The control unit 141 functions as a transport control unit 141A, a sorting control unit 141B, etc., by executing a sorting program. The sorting program is stored in the storage unit 142. The transport control unit 141A controls the operation of the transport unit 120. The sorting control unit 141B controls the sorting operation of the sorting unit 130. For example, the sorting control unit 141B controls the operation of multiple needles 131 according to the amount of displacement of the needles 131 and the load on the needles 131.

[0096] [Configuration of the sorting unit 130] The configuration of the sorting unit 130 will be described in detail below with reference to Figure 13. Figure 13 shows the cross-sectional structure of the second sorting system 1B, perpendicular to the transport direction, in the section where sorting is performed by the sorting unit 130. As shown in Figure 13, the sorting unit 130 includes a displacement adjustment unit 133. The displacement adjustment unit 133 independently displaces each of the multiple needles 131 toward the second section 122.

[0097] The displacement adjustment unit 133 may be, for example, an actuator for independently displacing each of the multiple needles 131. The sorting control unit 141B controls the actuator corresponding to each of the multiple needles 131, thereby independently displacing the multiple needles 131 toward the second part 122 until each of the multiple needles 131 reaches a specific load or a predetermined displacement.

[0098] The sorting unit 130 is equipped with a displacement adjustment unit 133. This prevents the displacement of other needles 131 from being hindered by contact between a specific needle 131 and an object 3 when multiple needles 131 simultaneously come into contact with multiple objects 3. In other words, the displacement adjustment unit 133 functions as a buffer that, when any of the multiple needles 131 come into contact with the first object 3A, allows the needles 131 that are not in contact with the first object 3A to be displaced toward the second unit 122.

[0099] For example, in the example shown in Figure 13, the needles 131 that come into contact with the first object to be sorted 3A are pressed against the first object to be sorted 3A until a specific load is reached, without penetrating the first object to be sorted 3A. The needles 131 that do not come into contact with the first object to be sorted 3A are displaced toward the second portion 122 more than the needles 131 that come into contact with the first object to be sorted 3A. Then, the needles 131 that do not come into contact with the first object to be sorted 3A and come into contact with the second object to be sorted 3B penetrate the second object to be sorted 3B.

[0100] The second part 122 comprises a plurality of recesses 122H that are lower than the inclined surface 122S supporting the object to be sorted 3. The recesses 122H are, for example, grooves (recesses) that extend in the direction of transport of the object to be sorted 3. Each recess 122H is positioned to correspond to each of the plurality of needles 131 provided by the sorting section 130. The recesses 122H allow the needles 131 to be displaced below the inclined surface 122S. Therefore, the needles 131 can be inserted more deeply into the relatively thin second object to be sorted 3B, making it more difficult for the needles 131 to come out of the second object to be sorted 3B.

[0101] [Effects of the second embodiment] (2-1) By combining the first sorting system 1A and the second sorting system 1B, even if there are objects 3 that cannot be sorted by one system, those objects 3 can be sorted by the other system. The second sorting system 1B is equipped with a buffer, so that even if one of the multiple needles 131 comes into contact with the first object 3A, the needles 131 that are not in contact with the first object 3A can be further displaced toward the second part 122. Therefore, even when multiple needles 131 are pressed against multiple objects 3 that have different hardnesses, a suitable load can be applied to the objects 3 from each needle 131. Thus, multiple objects 3 can be sorted simultaneously using multiple needles 131. Furthermore, even relatively large objects 3 with a maximum length of 20 mm or more can be sorted suitably with the second sorting system 1B.

[0102] (2-2) The displacement adjustment unit 133 of the sorting unit 130 functions as a buffer by independently displacing each of the multiple needles 131 toward the second part 122. Even in this configuration, when any of the multiple needles 131 come into contact with the first sorting target 3A, the needles 131 that are not in contact with the first sorting target 3A can be further displaced toward the second part 122.

[0103] (2-3) The sorting section 130 presses multiple needles 131 against the object to be sorted 3 along a direction inclined from the vertical (normal direction of the inclined surface 122S). When the second object to be sorted 3B is lifted by raising the needles 131 in this state, the direction of gravity and the direction in which the needles 131 are released are not the same, so the second object to be sorted 3B is prevented from falling away from the needles 131. At this time, by placing the object to be sorted 3 on the inclined surface 122S, the load from the needles 131 can be applied to the second object to be sorted 3B in an appropriate manner.

[0104] (2-4) The second part 122 is provided with recesses 122H that are recessed more deeply than the inclined surface 122S at positions corresponding to each of the multiple needles 131, thereby allowing the needles 131 to be displaced to a greater depth than the inclined surface 122S. Therefore, the needles 131 can be inserted deeper into the second object to be sorted 3B, making it more difficult for the needles 131 to come out of the second object to be sorted 3B.

[0105] (2-5) The sorting target group 2 includes a first sorting target 3A containing plastic and a second sorting target 3B containing wood or rubber. The first sorting target 3A is harder than the second sorting target 3B. Therefore, by pressing the needle 131 against them, the first sorting target 3A, which the needle 131 cannot penetrate, and the second sorting target 3B, which the needle 131 can penetrate, can be separated.

[0106] [Example of modification of the second embodiment] The second embodiment described above can be implemented with the following modifications. The following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0107] As shown in Figure 14, the sorting unit 130 may perform sorting operations from different positions that are offset in a direction perpendicular to the conveying direction. For example, first, the sorting unit 130 performs a first sorting operation in which it presses a plurality of needles 131 toward the second section 122 from a first position and then pulls up the plurality of needles 131. In Figure 14, the needles 131 when the first sorting operation is performed are shown by a dashed line. Next, the sorting unit 130 performs a second sorting operation in which it presses a plurality of needles 131 toward the second section 122 from a second position that is offset by a predetermined distance from the first position in a direction perpendicular to the conveying direction and then pulls up the plurality of needles 131. In Figure 14, the needles 131 when the second sorting operation is performed are shown by a solid line. At this time, the distance from the first position to the second position is smaller than the distance between adjacent needles 131 in the plurality of needles 131, for example, half the distance between adjacent needles 131. This sorting method allows the needles 131 to make suitable contact with objects 3 to be sorted, even if the distance between adjacent needles 131 is smaller than the distance between adjacent needles 131. In this case, the second part 122 may be provided with recesses 122H at both the position of the needles 131 when performing the first sorting operation and the position of the needles 131 when performing the second sorting operation.

[0108] In the sorting unit 130, the direction in which the multiple needles 131 are arranged is not limited to a direction perpendicular to the conveying direction, but the multiple needles 131 may be arranged along the conveying direction. Furthermore, multiple rows of multiple needles 131 arranged perpendicular to the conveying direction may be arranged along the conveying direction.

[0109] The sorting target group 2 may include sorting target 3 made of a material that the needle 131 cannot penetrate under a specific load, and sorting target 3 made of a material that the needle 131 can penetrate. In other words, the second sorting system 1B can be applied to sorting other sorting target 3 besides the first sorting target 3A which contains plastic and the second sorting target 3B which contains wood or rubber. Furthermore, sorting target group 2 may also include a third sorting target other than the first sorting target 3A which contains plastic and the second sorting target 3B which contains wood or rubber. In this case, the specific load may be set appropriately according to the material of the sorting target 3.

[0110] If the object to be sorted 3 is of sufficient size (especially thickness), the second part 122 may have a flat inclined surface 122S without a recess 122H. If the needles 131 embedded in the second object to be sorted 3B do not come off unintentionally, the sorting unit 130 may press multiple needles 131 against the object to be sorted 3 in a vertical direction. In this case, the second part 122 may have a horizontal surface as a support part instead of an inclined surface 122S.

[0111] The displacement adjustment unit 133 of the sorting unit 130 only needs to function as a buffer by independently displacing each of the multiple needles 131 toward the second part 122. For example, as shown in Figure 15, the sorting unit 130 includes a base 134 to which multiple needles 131 are connected. The multiple needles 131 are connected to the base 134 via the displacement adjustment unit 133. In this case, the displacement adjustment unit 133 is an elastic member such as a spring that functions as a buffer. The sorting unit 130 displaces the multiple needles 131 toward the second part 122 by displacing the base 134 toward the second part 122. Even in this configuration, if any of the needles 131 come into contact with the first object to be sorted 3A, the displacement adjustment unit 133, which is an elastic member, deforms, thereby further displacing the needles 131 that are not in contact with the first object to be sorted 3A toward the second part 122.

[0112] Instead of the sorting section 130 having a displacement adjustment section 133 that functions as a buffer, the second section 122, which is a support section, may have a configuration that functions as a buffer. For example, as shown in Figure 16, the second section 122 may be configured to have a Young's modulus lower than that of the first object to be sorted 3A and a Young's modulus higher than that of the second object to be sorted 3B. In this case, the sorting section 130 may be configured to operate multiple needles 131 together by the base 134 without having a displacement adjustment section 133. Even in this configuration, when any of the needles 131 come into contact with the first object to be sorted 3A, the second section 122 flexes, thereby further displacing the needles 131 that are not in contact with the first object to be sorted 3A toward the second section 122.

[0113] [Third Embodiment] A third embodiment of the sorting system and sorting method will be described with reference to Figures 17 and 18. The third sorting system 1C shown in Figure 17 is the other system when the first sorting system 1A in the first embodiment is one of the upstream sorting system S1 and the downstream sorting system S2. Similar to the second sorting system 1B, the third sorting system 1C sorts the first sorting target 3A, which includes plastic, and the second sorting target 3B, which includes wood or rubber, according to the difference in their hardness.

[0114] If the third sorting system 1C is the upstream sorting system S1, the second sorting system 1B sorts multiple objects 3 before they are sorted by the first sorting system 1A. In this case, the objects 3 sorted by the third sorting system 1C are sorted as post-sorted objects by the first sorting system 1A, which is the downstream sorting system S2. Also, if the third sorting system 1C is the downstream sorting system S2, the third sorting system 1C sorts multiple objects 3 that have been sorted by the first sorting system 1A as post-sorted objects.

[0115] The third sorting system 1C is equipped with a transport unit 120 similar to that of the second sorting system 1B. Figure 17 illustrates the second part 122 of the transport unit 120 where sorting takes place, and the fourth part 124 to which the sorted second sorting target objects 3B are transported.

[0116] The third sorting system 1C comprises a sorting unit 210, an imaging unit 220, and a control device 230. The sorting unit 210 comprises a sorting needle 211 and an arm unit 212. The sorting needle 211 is attached to the tip of the arm unit 212, which is a robotic arm. The movement of the arm unit 212 is controlled by the control device 230.

[0117] In the sorting unit 210, the arm unit 212 is driven to press the sorting needle 211 against the sorting target object 3 placed on the inclined surface 122S, along the direction normal to the inclined surface 122S. At this time, the arm unit 212 presses the sorting needle 211 against the sorting target object 3 with a specific load. Therefore, the sorting needle 211 does not penetrate the first sorting target object 3A, which contains plastic, located in the second section 122, but penetrates only the second sorting target object 3B, which contains wood or rubber.

[0118] The sorting section 210 includes a detachment section 213 for removing the second object to be sorted 3B that has been impaled on the sorting needle 211. The detachment section 213 is located above the fourth section 124. The detachment section 213 is, for example, a plate-shaped member. The arm section 212 removes the second object to be sorted 3B impaled on the sorting needle 211 by pulling up the sorting needle 211 so that the second object to be sorted 3B that has been impaled on the sorting needle 211 comes into contact with the detachment section 213. The second object to be sorted 3B that has been removed from the sorting needle 211 falls toward the fourth section 124.

[0119] The imaging unit 220 acquires an image of the object to be sorted 3, which is placed on the second part 122, which functions as a support. The imaging unit 220 transmits the acquired image to the control device 230. Based on the image acquired by the imaging unit 220, the control device 230 acquires positional information of the object to be sorted 3, which is placed on the second part 122. Then, based on the acquired positional information, the control device 230 drives the arm 212 to press the sorting needle 211 against the object to be sorted 3 placed on the second part 122.

[0120] [Control device 230] As shown in Figure 18, the control device 230 is connected to the transport unit 120, the sorting unit 210, and the imaging unit 220. The control device 230 comprises a control unit 231, a storage unit 232, an input unit 233, an output unit 234, and a communication unit 235. The hardware configuration of the control device 230 can be the same as that of the control device 60 in the first embodiment.

[0121] The control unit 231 functions as a transport control unit 231A, an image processing unit 231B, a sorting control unit 231C, etc., by executing a sorting program. The sorting program is stored in the storage unit 232. The transport control unit 231A controls the operation of the transport unit 120. The image processing unit 231B is an example of a position information acquisition unit that acquires position information of the sorting target object 3 placed on the second part 122 based on the image acquired by the imaging unit 220. For example, the image processing unit 231B acquires the coordinates of the position where the sorting target object 3 is placed on the second part 122 as position information from the image acquired by the imaging unit 220. The sorting control unit 231C controls the operation of the sorting unit 210. For example, the sorting control unit 231C drives the arm unit 212 based on the position information acquired by the image processing unit 231B, thereby pressing the sorting needle 211 against the sorting target object 3 placed on the second part 122 with a specific load.

[0122] [Selection method in the third selection system 1C] In the third sorting system 1C, the sorting method first involves the imaging unit 220 acquiring an image of the sorting target 3 transported to the second section 122 and transmitting it to the control device 230. The image processing unit 231B acquires position information of any sorting target 3 (hereinafter referred to as a specific sorting target) placed on the second section 122 from the image acquired by the imaging unit 220. The sorting control unit 231C drives the arm section 212 based on the position information of the specific sorting target to press the sorting needle 211 against the specific sorting target placed on the second section 122 with a specific load.

[0123] If the object to be sorted is the first object to be sorted 3A, the sorting needle 211 cannot penetrate the first object to be sorted 3A because it is hard. Therefore, the first object to be sorted 3A is transported as is, in the same manner as in the first embodiment. If the object to be sorted is the second object to be sorted 3B, the sorting control unit 231C drives the arm 212 to pull up the sorting needle 211 so that the second object to be sorted 3B that has been impaled on the sorting needle 211 comes into contact with the detachment unit 213. This causes the second object to be sorted 3B that has been impaled on the sorting needle 211 to fall toward the fourth unit 124. In this way, the sorting unit 210 sorts the first object to be sorted 3A and the second object to be sorted 3B.

[0124] If the sorting needle 211 does not penetrate the specified object to be sorted, the detachment operation may be omitted and the system may proceed to the next sorting operation. In this case, for example, it may be determined whether or not the sorting needle 211 penetrated the object to be sorted 3 from a load sensor that measures the load on the sorting needle 211 or from an image captured by the imaging unit 220.

[0125] [Effects of the Third Embodiment] (3-1) By combining the first sorting system 1A and the third sorting system 1C, even if there are sorting targets 3 that cannot be sorted by one system, those sorting targets 3 can be sorted by the other system. Furthermore, the third sorting system 1C is configured to press the sorting needle 211 against a specific sorting target based on positional information. Therefore, the problem that can occur when multiple needles 131 are provided, where the entire set of multiple needles 131 stops descending when the needles 131 come into contact with a relatively hard sorting target 3, does not occur. In other words, with the configuration of the third sorting system 1C, sorting can be performed appropriately even when relatively hard sorting targets 3 and relatively soft sorting targets 3 are mixed together. Furthermore, the same effects as (2-3) to (2-5) in the second embodiment can be obtained with the third sorting system 1C as well. With the third sorting system 1C, even relatively large sorting targets 3 with a maximum length of 20 mm or more can be sorted appropriately.

[0126] [Example of modification of the third embodiment] The third embodiment described above can be implemented with the following modifications. The following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0127] The material of the object to be sorted 3 should include both the object to be sorted 3 made of a material that the sorting needle 211 cannot penetrate under a specific load, and the object to be sorted 3 made of a material that the sorting needle 211 can penetrate. In this case, the specific load should be set appropriately according to the material of the object to be sorted 3.

[0128] If the object to be sorted 3 is of sufficient size (especially thickness), the second part 122 may have a flat inclined surface 122S without a recess 122H. Alternatively, if the sorting needle 211 embedded in the second object to be sorted 3B does not come off unintentionally, the sorting unit 210 may be configured to press the sorting needle 211 against the object to be sorted 3 along the vertical direction. In this case, the second part 122 may have a horizontal surface as a support part instead of an inclined surface 122S.

[0129] In the third sorting system 1C, only sorting objects 3 having any desired appearance may be selected as specific sorting objects. For example, if the color or pattern of the second sorting object 3B can be limited, the system may be set to recognize only sorting objects 3 that match the color or pattern of the second sorting object 3B as specific sorting objects. For example, if there are second sorting objects 3B that include wood and second sorting objects 3B made of black rubber, the system may be set to recognize sorting objects 3 having a wood-grain or black appearance as specific sorting objects. In this case, the first sorting object 3A made of plastic with a wood-grain appearance and the second sorting object 3B containing wood are sorted by the sorting needle 211. Also, the first sorting object 3A made of black plastic and the second sorting object 3B made of black rubber are sorted by the sorting needle 211. With such a configuration, sorting can be performed efficiently.

[0130] [Fourth Embodiment] A fourth embodiment of the sorting system and sorting method will be described with reference to Figures 19 to 21. The fourth sorting system 1D shown in Figure 19 is the other system when the first sorting system 1A in the first embodiment is one of the upstream sorting system S1 and the downstream sorting system S2. Similar to the first sorting system 1A, the fourth sorting system 1D sorts the first sorting target 3A, which includes plastic, and the second sorting target 3B, which includes wood or rubber, according to their charge tendency. Charge tendency refers to the material-specific properties of how easily a substance becomes electrostatically charged and whether it tends to have a positive or negative charge when charged.

[0131] If the fourth sorting system 1D is the upstream sorting system S1, the fourth sorting system 1D sorts multiple objects 3 before they are sorted by the first sorting system 1A. In this case, the objects 3 sorted by the fourth sorting system 1D are sorted as post-sorted objects by the first sorting system 1A, which is the downstream sorting system S2. Also, if the fourth sorting system 1D is the downstream sorting system S2, the fourth sorting system 1D sorts multiple objects 3 that have been sorted as post-sorted objects by the first sorting system 1A.

[0132] The fourth sorting system 1D comprises a storage unit 310, a first recovery unit 311, and a second recovery unit 312. The storage unit 310 stores a group of sorting targets 2 consisting of multiple sorting targets 3 before sorting by the fourth sorting system 1D. The sorting target group 2 of the fourth sorting system 1D consists of multiple sorting targets 3 from which objects made of metallic material have been removed in a process prior to the fourth sorting system 1D. The first recovery unit 311 contains the first sorting target 3A. The second recovery unit 312 contains the second sorting target 3B.

[0133] The fourth sorting system 1D comprises a transport unit 320, a charging unit 330, a measuring unit 340, a sorting unit 350, and a control device 360. The control device 360 ​​controls the transport unit 320, the charging unit 330, the measuring unit 340, and the sorting unit 350.

[0134] The transport unit 320 transports the sorting targets 3 from the storage unit 310 to the first recovery unit 311 or the second recovery unit 312. The transport unit 320 is, for example, a conveyor, but other devices such as a robotic arm may also be used. The sorting targets 3 are arranged in the transport unit 320 so that sufficient distance is maintained between each other. In Figure 19, the transport path TR2 of the sorting targets 3 by the transport unit 320 is shown by a solid line or a dashed-dot arrow.

[0135] The transport unit 320 comprises, for example, a first part 321, a second part 322, and a third part 323. The objects to be sorted 3 are first transported from the storage unit 310 to the charging unit 330 by the first part 321. The charging unit 330 charges the objects to be sorted 3 while they are being transported. The first part 321 drops the charged objects to be sorted 3 toward the sorting unit 350. The charge level of the objects to be sorted 3 while they are falling is measured by the charge level measuring unit 341 of the measuring unit 340. After the charge level measurement, the objects to be sorted 3 are sorted by the sorting unit 350 into either the second part 322 or the third part 323 according to the charge level measurement result, and then transported to the first recovery unit 311 or the second recovery unit 312.

[0136] The charging unit 330 is, for example, a charging device such as a charging bar that charges the objects to be sorted 3 during transport by corona discharge. With such a charging device, it is possible to stably impart a similar amount of charge to multiple objects to be sorted 3 made of materials with the same charging tendency. The charging unit 330 may charge the objects to be sorted 3 to the positive side or to the negative side.

[0137] The distance from the charged section 330 to the object to be sorted 3 is, for example, 10 mm to 200 mm. The charged section 330 may be fixed so as to be at a constant distance from the conveying section 320, or it may be mounted so as to be at an adjustable distance from the conveying section 320.

[0138] The measuring unit 340 comprises a charge amount measuring unit 341 and a distance measuring unit 342. The charge amount measuring unit 341 measures the charge amount of the object to be sorted 3, which has been charged by the charging unit 330. The charge amount measuring unit 341 is, for example, a surface potential meter, but is not particularly limited as long as it is a measuring instrument capable of quantifying the charge amount. The distance measuring unit 342 measures the distance from the charge amount measuring unit 341 to the object to be sorted 3. The distance measuring unit 342 is, for example, a laser distance meter.

[0139] The measurement results from the charge amount measuring unit 341 and the distance measuring unit 342 are input to the control device 360. The control device 360 ​​controls the sorting unit 350 according to the charge amount measurement result measured by the charge amount measuring unit 341 and the distance from the charge amount measuring unit 341 to the sorting target object 3 measured by the distance measuring unit 342.

[0140] The measurements by the charge amount measuring unit 341 and the distance measuring unit 342 are performed on the object to be sorted 3 while it is falling. If the charge amount were measured with the charged object to be sorted 3 placed on a conductive material, there is a possibility that the charge from the charged object to be sorted 3 could transfer from the object to be sorted 3 to the conductive material. Also, if the charge amount were measured with the charged object to be sorted 3 placed on an insulating material, the insulating material itself could become charged, potentially affecting the measurement results. In this respect, by performing the measurement on the object to be sorted 3 in the air, the above-mentioned influences can be eliminated and the charge amount can be measured, thereby improving the accuracy of the charge amount measurement results.

[0141] When dropping the object to be sorted 3, there is a possibility of variation in the distance from the charge amount measurement unit 341 to the object to be sorted 3. The distance from the charge amount measurement unit 341 to the object to be sorted 3 may also vary depending on the size of the object to be sorted 3. Therefore, the control device 360 ​​controls the sorting unit 350 according to the measurement result of the charge amount of the object to be sorted 3 by the charge amount measurement unit 341 and the distance measured by the distance measurement unit 342. This reduces the impact of variations in the distance from the charge amount measurement unit 341 to the object to be sorted 3 on the measurement accuracy of the charge amount measurement unit 341.

[0142] The objects to be sorted 3 that fall from the first section 321 are measured by the measuring unit 340 and then reach the sorting unit 350. The sorting unit 350 sorts the objects to be sorted 3 according to the control signal from the control device 360. The method of controlling the sorting unit 350 by the control device 360 ​​will be described later.

[0143] The sorting unit 350 sorts the objects to be sorted 3 by changing the transport path TR2 in accordance with the control signal from the control device 360. Specifically, the sorting unit 350 transports the objects to be sorted 3 to either the second section 322 or the third section 323 in accordance with the control signal from the control device 360 ​​output according to the measurement result from the measurement unit 340.

[0144] Based on the above, the sorting method by the fourth sorting system 1D includes the steps of: the charging unit 330 charging the object to be sorted 3; the measuring unit 340 measuring the amount of charge on the object to be sorted 3; and the sorting unit 350 sorting the object to be sorted 3 according to the measurement result of the amount of charge. In the fourth sorting system 1D, the above steps are performed on the object to be sorted 3 while it is being transported by the transport unit 320.

[0145] Furthermore, the sorted objects 3 may undergo even more detailed sorting after the initial sorting. For example, after sorting by charging them to one positive or negative state with the charging unit 330, the sorted objects 3 may be charged to the other positive or negative state and then sorted again.

[0146] [Control device 360] As shown in Figure 20, the control device 360 ​​is connected to the transport unit 320, the charging unit 330, the measurement unit 340, and the sorting unit 350. The control device 360 ​​comprises a control unit 361, a storage unit 362, an input unit 363, an output unit 364, and a communication unit 365. The hardware configuration of the control device 360 ​​can be the same as the hardware configuration of the control device 60 in the first embodiment.

[0147] The control unit 361 functions as a transport control unit 361A, a charge control unit 361B, a sorting control unit 361C, etc., by executing a sorting program. The sorting program is stored in the storage unit 362.

[0148] The transport control unit 361A controls the operation of the transport unit 320. The charging control unit 361B controls various operations of the charging unit 330, such as turning it on and off and adjusting the output voltage. The sorting control unit 361C controls the sorting operation of the sorting unit 350 according to the measurement results of the measurement unit 340.

[0149] Here, we will explain how the sorting unit 350 is controlled by the sorting control unit 361C. Figure 21 shows an example of the triboelectric series, which relatively represents the charging tendencies of several types of materials. As shown in Figure 21, most plastics, with the exception of nylon (polyamide), are less likely to lose electrons and tend to become negatively charged than rubber or wood. Nylon, on the other hand, is more likely to lose electrons and tend to become positively charged than rubber or wood.

[0150] When the sorting target objects 3 are charged by the charging unit 330, each sorting target object 3 will have a charge corresponding to the charging tendency of the material. For example, consider a case where the first sorting target object 3A is made of plastic such as polyethylene or polystyrene, and the second sorting target object 3B is made of wood or rubber. In this case, if each of the first sorting target object 3A and the second sorting target object 3B is charged to the negative side by the charging unit 330, the first sorting target object 3A will exhibit a negative potential with a larger absolute value compared to the second sorting target object 3B. For example, consider a case where the first sorting target object 3A is made of nylon, and the second sorting target object 3B is made of wood or rubber. In this case, if each of the first sorting target object 3A and the second sorting target object 3B is charged to the positive side by the charging unit 330, the first sorting target object 3A will exhibit a positive potential with a larger absolute value compared to the second sorting target object 3B.

[0151] The sorting control unit 361C controls the operation of the sorting unit 350 based on pre-set judgment information and the measurement results from the measurement unit 340. The judgment information is stored in the storage unit 362. The judgment information is, for example, information that associates one or more judgment conditions, such as a numerical range or threshold, for the measurement result of the charge amount by the charge amount measurement unit 341, with sorting operation commands for the sorting unit 350 in cases where the measurement result satisfies the judgment condition and when it does not.

[0152] The sorting control unit 361C determines whether the charge measurement result from the charge measurement unit 341 satisfies the determination conditions, and then controls the sorting unit 350 to perform sorting operations according to the determination result. As an example, consider the case where a first sorting target object 3A made of plastic and a second sorting target object 3B made of rubber or wood, which are less likely to become negatively charged than the first sorting target object 3A, are to be sorted. In this case, the determination conditions are numerical ranges or thresholds for distinguishing between the charge amount shown by the first sorting target object 3A and the charge amount shown by the second sorting target object 3B when each of the first sorting target object 3A and the second sorting target object 3B are negatively charged by the charging unit 330.

[0153] For example, if the charge measurement result from the charge measurement unit 341 shows a negative potential with an absolute value greater than the threshold, it can be determined that the object to be sorted 3 is the first object to be sorted 3A. In this case, the sorting control unit 361C controls the sorting unit 350 to transport the object to be sorted 3 to the second section 322.

[0154] Conversely, if the charge measurement result from the charge measurement unit 341 shows a negative potential with an absolute value smaller than the threshold, it can be determined that the object to be sorted 3 is the second object to be sorted 3B. In this case, the sorting control unit 361C controls the sorting unit 350 to transport the object to be sorted 3 to the third section 323.

[0155] The determination conditions may, for example, be a numerical range or threshold value relative to the value obtained by correcting the measured charge amount by the charge amount measuring unit 341 with the distance measured by the distance measuring unit 342. Alternatively, the determination conditions may be defined as a function that has the distance measured by the distance measuring unit 342 as a variable, or as a table corresponding to the distance measured by the distance measuring unit 342, where the numerical range or threshold value of the measured charge amount by the charge amount measuring unit 341 is used.

[0156] The determination conditions may be set for each charging condition when the object to be sorted 3 is charged by the charging unit 330. The charging conditions may include, for example, the output of the charging unit 330, the distance from the charging unit 330 to the object to be sorted 3, the material of the object to be sorted 3 included in the object to be sorted group 2, the shape of the object to be sorted 3, and ambient environmental conditions such as humidity.

[0157] [Effects of the Fourth Embodiment] (4-1) By combining the first sorting system 1A and the fourth sorting system 1D, even if there are sorting targets 3 that cannot be sorted by one system, those sorting targets 3 can be sorted by the other system. Furthermore, by sorting the sorting targets 3 according to the measurement result obtained by measuring the amount of charge of the sorting targets 3 charged by the charging unit 330 using the charge amount measuring unit 341, the sorting targets 3 can be sorted according to the charging tendency of the material. The fourth sorting system 1D can also suitably sort relatively large sorting targets 3, such as those with a maximum length of 20 mm or more.

[0158] (4-2) The sorting control unit 361C controls the sorting operation of the sorting unit 350 based on the charge measurement result from the charge measurement unit 341 and the distance from the charge measurement unit 341 to the sorting target object 3 measured by the distance measurement unit 342. This corrects errors in the charge measurement result due to variations in the distance from the charge measurement unit 341 to the sorting target object 3. Therefore, the sorting target object 3 can be sorted with greater accuracy.

[0159] (4-3) The charge measurement unit 341 measures the charge of the object to be sorted 3 in the air. This improves the accuracy of the charge measurement result by the charge measurement unit 341 compared to when measuring the charge of the object to be sorted 3 placed on a conductive or insulating material.

[0160] (4-4) According to the fourth sorting system 1D, based on the measurement results of the charge amount measuring unit 341, the first sorting target 3A containing plastic and the second sorting target 3B containing wood or rubber can be suitably sorted according to the charge tendency of the materials.

[0161] [Example of modification of the fourth embodiment] The fourth embodiment described above can be implemented with the following modifications. The following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0162] The fourth sorting system 1D can be applied not only to the sorting of the first sorting target object 3A containing plastic and the second sorting target object 3B containing wood or rubber, but also to the sorting of multiple sorting target objects 3 having different electrostatic tendencies. Furthermore, in the fourth sorting system 1D, the sorting target object group 2 may also include a third sorting target object other than the first sorting target object 3A containing plastic and the second sorting target object 3B containing wood or rubber.

[0163] The sorting target group 2 may include a plurality of first sorting target objects 3A made of plastic materials having different charging tendencies. In this case, the plurality of first sorting target objects 3A may include first sorting target objects 3A containing a first plastic that tends to be negatively charged compared to second sorting target objects 3B containing wood or rubber, and first sorting target objects 3A containing a second plastic that tends to be positively charged. The first plastic is, for example, polyethylene or polystyrene. The second plastic is, for example, nylon. In this case, by performing sorting in two stages, the first sorting target objects 3A containing the first plastic and the first sorting target objects 3A containing the second plastic can be separated from the second sorting target objects 3B. For example, by first positively charging the sorting target object 3 and performing sorting, the first sorting target objects 3A containing the second plastic that tends to be positively charged can be separated from the sorting target group 2. Then, by negatively charging the remaining first plastic, which is included in the first sorting target 3A, and the second sorting target 3B, and performing the sorting, it is possible to separate the first sorting target 3A and the second sorting target 3B, which are prone to negative charging, from the first plastic, which is included in the first sorting target 3A.

[0164] If the charge measurement unit 341 can accurately measure the charge of the object to be sorted 3, the configuration for measuring the charge of the object to be sorted 3 in the air may be replaced with a configuration for measuring the charge of the object to be sorted 3 placed on any material. In this case, if the distance from the charge measurement unit 341 to the object to be sorted 3 is approximately constant, the distance measurement unit 342 may not be provided. However, if the distance from the charge measurement unit 341 to the object to be sorted 3 varies due to variations in the size of the object to be sorted 3, the distance measurement unit 342 may be provided.

[0165] The charging unit 330 may charge the object to be sorted 3 by any method other than corona discharge (for example, friction). The charging unit 330 may be equipped with a position adjustment mechanism to adjust the distance from the transport unit 320 to the charging unit 330, in order to maintain a constant distance from the charging unit 330 to the objects to be sorted 3. The position adjustment mechanism is controlled by the control unit 361. For example, first, the distance from the charging unit 330 to the objects to be sorted 3 is measured by a second distance measuring unit separate from the first distance measuring unit 342, or by means such as image recognition. Then, the control unit 361 controls the position adjustment mechanism to maintain a constant distance from the charging unit 330 to the objects to be sorted 3 according to the measurement result of the distance from the charging unit 330 to the objects to be sorted 3. With such a configuration, even if there is variation in the distance from the charging unit 330 to the objects to be sorted 3 due to variations in the size and shape of the objects to be sorted 3, a similar amount of charge can be stably applied to multiple objects to be sorted 3 made of materials with the same charging tendency. [Explanation of symbols]

[0166] TR1... Transport route 1A…First sorting system 2…Group of items to be sorted 3…Items to be sorted 3A...Items subject to first sorting 3B...Items subject to second sorting 10...Storage section 11…Recovery Department 20…Conveyor Unit 21…Part 1 22…Second part 23...Third part 30…Sound collection unit 31… Metal components 31A…Protrusion 32…Soundproofing materials 33…Sound collection section 34…Sound collection space 40…Acoustic analysis department 50… Sorting Department 60...Control device 61... Control Unit 62...Storage section

Claims

1. A transport unit that transports the objects to be sorted so that they pass through a sound collection space, A sound collection unit that collects sound when the object to be sorted passes through the sound collection space and comes into contact with the member surrounding the sound collection space, The sound collection unit performs spectral analysis to decompose the sound collected by the sound collection unit into frequency components, A sorting unit for sorting the objects to be sorted that have passed through the sound collection space, The system includes a control unit that controls the sorting unit based on the frequency components of the first frequency band in the results of the spectral analysis. Sorting system.

2. The control unit controls the sorting unit based on the determination result obtained from the spectral analysis, which determines whether the representative value of the frequency component in the first frequency band is greater than or equal to a threshold. The sorting system according to claim 1.

3. The control unit controls the sorting unit based on the results of comparing the representative value of the frequency component in the first frequency band with the representative value of the frequency component in a second frequency band different from the first frequency band, as determined by the spectral analysis. The sorting system according to claim 1.

4. The aforementioned object to be sorted is one of several objects to be sorted. The aforementioned plurality of sorting targets include a first sorting target containing plastic and a second sorting target containing rubber, The control unit controls the sorting unit to sort the plurality of objects to be sorted into first objects and second objects based on the frequency components of the first frequency band in the results of the spectral analysis. A sorting system according to any one of claims 1 to 3.

5. The lower limit of the first frequency band is 1000 Hz or higher. The sorting system according to claim 4.

6. The member enclosing the sound-collecting space is provided with a projection that extends toward the sound-collecting space. A sorting system according to any one of claims 1 to 3.

7. The maximum length of the object to be sorted is 20 mm or more. A sorting system according to any one of claims 1 to 3.

8. The system comprises an upstream sorting system and a downstream sorting system that performs sorting on the sorted objects selected by the upstream sorting system. One of the upstream sorting system and the downstream sorting system comprises the transport unit, the sorting unit which is the first sorting unit, the sound collection unit, the acoustic analysis unit, and the control unit. The other of the upstream sorting system and the downstream sorting system is A support section for supporting multiple objects taken from a group of objects to be sorted, which includes a first object to be sorted and a second object to be sorted that is softer than the first object to be sorted, The system includes a second sorting unit that presses a plurality of needles against the plurality of objects placed on the support unit with a specific load, The specified load is set such that the needles that come into contact with the first object to be sorted do not penetrate the first object to be sorted, and the needles that come into contact with the second object to be sorted penetrate the second object to be sorted. The other system includes a buffer that, when any of the plurality of needles comes into contact with the first object to be sorted, allows the needles that are not in contact with the first object to be sorted to be displaced toward the support portion. A sorting system according to any one of claims 1 to 3.

9. The system comprises an upstream sorting system and a downstream sorting system that performs sorting on the sorted objects selected by the upstream sorting system. One of the upstream sorting system and the downstream sorting system comprises the transport unit, the sorting unit which is the first sorting unit, the sound collection unit, the acoustic analysis unit, and the control unit. The other of the upstream sorting system and the downstream sorting system is A support section on which a specific sorting target object, which is either a first sorting target object or a second sorting target object that is softer than the first sorting target object, is placed, A location information acquisition unit that acquires location information of the specific object to be sorted, which is placed on the support unit, The system includes a second sorting unit that, based on the position information acquired by the position information acquisition unit, presses a sorting needle with a specific load against the specific sorting target object placed on the support unit. A sorting system according to any one of claims 1 to 3.

10. The system comprises an upstream sorting system and a downstream sorting system that performs sorting on the sorted objects selected by the upstream sorting system. One of the upstream sorting system and the downstream sorting system comprises the transport unit, the sound collection unit, the acoustic analysis unit, the sorting unit which is the first sorting unit, and the control unit which is the first control unit. The other of the upstream sorting system and the downstream sorting system is A charging unit that charges the target object, A charge amount measuring unit that measures the amount of charge on the object that has been charged by the charging unit, A second sorting unit for sorting the aforementioned objects, The system includes a second control unit that controls the second sorting unit according to the measurement result of the amount of charge. A sorting system according to any one of claims 1 to 3.

11. Transporting the objects to be sorted so that they pass through the sound collection space, The process involves collecting sound when the object to be sorted passes through the sound collection space and comes into contact with the member surrounding the sound collection space. Perform spectral analysis to decompose the collected sound into frequency components, This includes selecting the objects to be sorted that have passed through the sound collection space based on the frequency components of the first frequency band in the results of the spectral analysis. Selection method.

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