Abnormality detection system

Abstract

To improve detection accuracy of signs of failure of a power transmission belt.SOLUTION: An anomaly detection system provided herein is configured to detect anomalies of a belt based on a result of comparison between a signal generated by reading an information carrier fixed on a surface of a power transmission belt using a reader device and a reference signal.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a technique for detecting an abnormality in a belt for power transmission.

Background Art

[0002] A technique for detecting damage to a belt conveyor is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, with the technique described in Patent Document 1, although damage to the belt can be detected, elongation of the belt cannot be detected. Belt elongation is one of the signs of belt failure. Therefore, if belt elongation cannot be detected, the accuracy of detecting signs of belt failure decreases.

[0005] One object of the present invention is to improve the accuracy of detecting signs of failure of a belt for power transmission.

Means for Solving the Problems

[0006] One aspect of the present invention provides an abnormality detection system that detects an abnormality related to the belt based on a comparison result between a signal generated by reading, with a reading device, an information holding body fixed to the surface of a belt for power transmission and a reference signal.

[0007] The information holding body having different information depending on the position in the driving direction of the belt is fixed to the surface of the belt, and the abnormality detection system may specify an abnormal portion of the belt based on the comparison result.

[0008] Each of the signal generated by the reading device and the reference signal may be a signal of the same pseudo-random sequence in which the autocorrelation value is 1 and the cross-correlation value is 0.

[0009] Each of the signal generated by the reading device and the reference signal may be a signal obtained by Manchester-encoding the pseudo-random sequence.

[0010] The belt may be a toothed belt.

[0011] The belt rotates and moves along with the rotation of a rotating member that contacts the belt and applies tension, and the reading device may read the information storage body in the vicinity of the rotating member.

[0012] The abnormality detection system may detect the elongation or contraction of the belt based on the difference in the time axis direction between the waveform of the signal generated by the reading device and the waveform of the reference signal.

[0013] Each of the signal generated by the reading device and the reference signal has a pulse waveform, and the abnormality detection system may detect the elongation or contraction of the belt based on the comparison result between the time width of the high level period or the low level period included in the signal generated by the reading device and the time width of the corresponding period included in the reference signal.

[0014] Each of the signal generated by the reading device and the reference signal has a pulse waveform, and the abnormality detection system may determine the degree of abnormality based on the difference between the time width of the high level period or the low level period included in the signal generated by the reading device and the time width of the corresponding period included in the reference signal.

Advantages of the Invention

[0015] According to the present invention, the detection accuracy of the failure omen of the belt for power transmission is improved.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0017] 1. Configuration FIG. 1 is a diagram showing an example of the internal configuration of the abnormality detection system 1 according to the present embodiment. In the present embodiment, the case where the abnormality detection system 1 is applied to the abnormality detection of the timing belt 12 of the home door device 10 will be described as an example. The abnormality of the timing belt 12 includes a sign of a failure such as elongation of the timing belt 12. When the timing belt 12 elongates, the accuracy of controlling the position of the door 14 of the home door device 10 decreases. Therefore, in the home door device 10, the allowable range of the elongation amount of the timing belt 12 is small. Further, if the timing belt 12 is used continuously while being elongated, there is a risk that the timing belt 12 will break and the home door device 10 will stop operating. Therefore, when the timing belt 12 elongates, it is preferable to replace the timing belt 12 early.

[0018] The abnormality detection system 1 includes a home door device 10, a photosensor 20, and a state management device 30. The home door device 10 is installed in a part facing the track on the platform of a railway station and is used to prevent passengers from falling onto the track or getting into contact accidents with trains. The photosensor 20 and the state management device 30 are used to detect abnormalities related to the timing belt 12 of the home door device 10. The state management device 30 is connected to a server device 40 via a network such as a LAN (Local Area Network) or the Internet.

[0019] FIG. 1 shows a state in which the front panel of the housing 11 of the home door device 10 is removed. The home door device 10 includes a housing 11, a timing belt 12, pulleys 13a and 13b (hereinafter also collectively referred to as "pulley 13"), a door 14, a control device 15, and a connecting member 16. The housing 11 houses the timing belt 12, the pulleys 13a and 13b, the door 14, the control device 15, the connecting member 16, the photosensor 20, and the state management device 30.

[0020] The timing belt 12 is an endless toothed belt wound around the pulleys 13a and 13b and opens and closes the door 14. The outer peripheral surface of the timing belt 12 is flat, and teeth are provided on the inner peripheral surface. The timing belt 12 is an example of the belt for power transmission according to the present invention. Since the timing belt 12 is formed of a resin such as rubber, elongation occurs due to deterioration during use, and it may break when further deteriorated.

[0021] Pulleys 13a and 13b are both toothed pulleys, which mesh with the timing belt 12 to apply tension and cause the timing belt 12 to rotate and move. Also, pulleys 13a and 13b are provided with flanges to prevent the timing belt 12 from coming off. Pulleys 13a and 13b are an example of the rotating members according to the present invention. Pulley 13a is a driving pulley, which is driven by a motor and rotates clockwise or counterclockwise in the figure about an axis. When pulley 13a rotates, the timing belt 12 rotates and moves in the direction of the arrow in the figure. The moving direction of the timing belt 12 is an example of the driving direction according to the present invention. Pulley 13b is a driven pulley, which rotates clockwise or counterclockwise in the figure about an axis as the pulleys 13a and the timing belt 12 rotate.

[0022] The door 14 opens and closes an opening facing the track on the platform. The door 14 is connected to the timing belt 12 by a connecting member 16, and moves between the closed position shown in Fig. 1(a) and the open position shown in Fig. 1(b) as the timing belt 12 rotates. The door 14 basically operates in a predetermined operation pattern. When the train arrives at the platform, the door 14 accelerates from the state of stopping at the closed position until it reaches a constant speed, then moves at a constant speed, decelerates, and then stops at the open position. When closing the door 14, the door 14 accelerates from the state of stopping at the open position until it reaches a constant speed, then moves at a constant speed, decelerates, and then stops at the closed position.

[0023] The control device 15 controls the opening and closing of the door 14 by rotating the motor of the pulley 13a clockwise or counterclockwise in the figure.

[0024] FIG. 2 is a plan view showing an example of the outer peripheral surface of the timing belt 12. The outer peripheral surface of the timing belt 12 is an example of the surface according to the present invention. The surface referred to here means a surface that can be read by the photosensor 20. A barcode is printed on the outer peripheral surface of the timing belt 12 so as to go around the outer peripheral surface by the printer. The barcode indicates a signal obtained by Manchester-encoding a pseudo-random sequence. The barcode is an example of the information carrier according to the present invention.

[0025] The pseudo-random sequence is a sequence of numbers having random number characteristics. The pseudo-random sequence used here is a random sequence of 1s and 0s, and has an autocorrelation value of 1 and a cross-correlation value of 0. The pseudo-random sequence is, for example, a pseudo-noise sequence, and preferably an M-sequence (Maximum Length Sequence). However, the pseudo-random sequence is not limited to the M-sequence, and other pseudo-random sequences may be used. The pseudo-random sequence has different patterns depending on the position. Therefore, the position of a value in the pseudo-random sequence can be specified by reading, as a pattern, a sequence of a predetermined length before and after a certain value included in the pseudo-random coefficient.

[0026] The pseudo-random sequence is Manchester-encoded so that the width of one period of the signal can be accurately recognized even if the pseudo-random sequence includes a long sequence of consecutive 0s or 1s. By Manchester encoding, the value 1 in the pseudo-random sequence is converted to 1 and 0, and the value 0 in the pseudo-random sequence is converted to 0 and 1. Further, the Manchester-encoded signal includes a clock.

[0027] In the example shown in FIG. 2, the value 0 included in the Manchester-encoded signal is represented by the black bars of the barcode, and the value 1 is represented by the white spaces. Since the pseudo-random sequence has different patterns depending on the position as described above, the barcode also has different information depending on the position in the moving direction of the timing belt 12. When elongation occurs in the timing belt 12, the width of the black bars or the width of the white spaces of the barcode increases. On the other hand, when contraction occurs in the timing belt 12, the width of the black bars or the width of the white spaces of the barcode decreases. Also, when a scratch occurs in the timing belt 12, at least a part of the black bars or the white spaces of the barcode is missing.

[0028] Returning to FIG. 1, the photosensor 20 is installed at a position facing the outer peripheral surface of the timing belt 12 in the vicinity of the pulley 13b. The vicinity referred to here means a position on the timing belt 12 where a tension equal to or greater than a predetermined tension is applied by the pulley 13b. For example, the vicinity is a position within a predetermined range from the position where the timing belt 12 contacts the pulley 13b where the barcode can be read. The photosensor 20 reads the barcode printed on the outer peripheral surface of the timing belt 12 and generates a read signal. For example, the photosensor 20 has a light emitting part and a light receiving part, irradiates the barcode with light from the light emitting part, receives the reflected light with the light receiving part, and converts it into an electrical signal. The photosensor 20 is an example of the reading device according to the present invention. In the example shown in FIG. 2, a read signal is generated with the black bar portion of the barcode being 0 and the white space portion being 1. This read signal has a pulse waveform.

[0029] FIG. 3 is a diagram showing an example of the functional configuration of the state management device 30. The state management device 30 includes an A / D (Analog-to-digital) conversion unit 31, a high-speed sampling unit 32, a storage unit 33, a waveform generation unit 34, a comparison unit 35, an abnormality detection unit 36, and a notification unit 37. These functions may be realized by hardware resources such as circuits and memories, or may be realized by the cooperation of software and hardware resources. For example, the storage unit 33 is realized by a memory, and at least a part of the functions other than the storage unit 33 may be realized by a processor such as a CPU (Central Processing Unit) executing a program stored in the memory to perform calculations or control a communication device.

[0030] The A / D conversion unit 31 converts the reading signal generated by the photosensor 20 from an analog signal to a digital signal.

[0031] The high-speed sampling unit 32 performs high-speed sampling on the reading signal converted by the A / D conversion unit 31 at a sampling frequency higher than its sampling frequency. In high-speed sampling, for example, a sampling frequency of 10 times or more the original sampling frequency is used. FIG. 4 is a diagram showing an example of high-speed sampling. Here, it is assumed that the symbol rate of the Manchester code is T / 10 and the sampling frequency is T, which is 10 times this symbol rate. In this case, the reading signal is high-speed sampled at the sampling frequency T. Due to this high-speed sampling, 10 signal values are included in one cycle.

[0032] Returning to FIG. 3, the storage unit 33 stores the read signal in the initial state as a reference signal. This reference signal is, like the read signal, a signal obtained by Manchester-encoding a pseudo-random sequence. Specifically, when the home door apparatus 10 is installed, an operation of opening and closing the door 14 is performed. At this time, the barcode on the timing belt 12 is read by the photosensor 20, and a read signal in the initial state is generated. This read signal is converted into a digital signal by the A / D conversion unit 31, and is high-speed sampled by the high-speed sampling unit 32, and then stored in the storage unit 33 as a reference signal. Note that the operation of opening and closing the door 14 may be performed multiple times when the home door apparatus 10 is installed. In this case, any one of the plurality of read signals generated by these operations may be stored as the reference signal.

[0033] The waveform generation unit 34 generates a waveform indicating the reference signal read from the storage unit 33. The reference signal has a pulse waveform.

[0034] The comparison unit 35 is, for example, a comparator, and compares the read signal obtained by the high-speed sampling of the high-speed sampling unit 32 with the reference signal whose waveform is generated by the waveform generation unit 34, and outputs the comparison result. Note that the read signal and the reference signal may be synchronized prior to this comparison. As a synchronization method, for example, a cross-correlation value is calculated by taking the product while shifting the read signal and the reference signal by a predetermined time each, a delay time is obtained from the position of the peak of the cross-correlation value, and the read signal or the reference signal is shifted by this delay time.

[0035] The comparison unit 35 outputs a value of 0 when, for example, the read signal and the reference signal match, and outputs a value of 1 when they do not match. When the timing belt 12 is in a normal state, the read signal has the same waveform as the comparison signal. In this case, since the read signal and the comparison signal match, a signal with all values being 0 is output from the comparison unit 35 as the comparison result. On the other hand, when the timing belt 12 stretches or shrinks, the read signal has a waveform different from that of the comparison signal. In this case, since at least a part of the read signal and the comparison signal do not match, a signal with at least a part of the values being 1 is output from the comparison unit 35 as the comparison result.

[0036] FIG. 5 is a diagram showing an example of the waveforms of the reference signal and the read signal. In FIG. 5, the vertical axis represents the amplitude and the horizontal axis represents the time. FIG. 5 shows an example when the timing belt 12 stretches. When the timing belt 12 stretches, a difference occurs in the time axis direction between the waveforms of the reference signal and the read signal. In the example shown in FIG. 5, the time width of the low-level period TA included in the reference signal is 10T, and the time width of the corresponding low-level period TA included in the read signal is 11T. The time width 11T of the low-level period TA included in the read signal is larger than the time width 10T of the low-level period TA included in the reference signal by the length corresponding to one sampling period. This indicates that a stretch corresponding to the length of one sampling period has occurred at the position corresponding to the low-level period TA of the read signal in the timing belt 12. Also, the time width of the high-level period TB included in the reference signal is 5T, and the time width of the corresponding high-level period TB included in the read signal is 6T. The time width 6T of the high-level period TB included in the read signal is larger than the time width 5T of the high-level period TB included in the reference signal by the length corresponding to one sampling period. This indicates that a stretch corresponding to the length of one sampling period has occurred at the position corresponding to the high-level period TB of the read signal in the timing belt 12. In the example shown in FIG. 5, since a non-matching portion occurs between the read signal and the comparison signal in the low-level period TA and the high-level period TB, a signal with the value of this portion being 1 is output from the comparison unit 35 as the comparison result.

[0037] Returning to FIG. 3, the abnormality detection unit 36 detects an abnormality in the timing belt 12 based on the comparison result output from the comparison unit 35. The abnormalities of this timing belt 12 include elongation, contraction, scratches, and dirt. For example, when the comparison result output from the comparison unit 35 indicates that the read signal and the reference signal match, the abnormality detection unit 36 does not detect an abnormality in the timing belt 12. On the other hand, as shown in FIG. 5, when the comparison result output from the comparison unit 35 indicates that the reference signal and the read signal do not match during the low-level period TA and the high-level period TB, the abnormality detection unit 36 detects elongation or contraction of the timing belt 12. Also, when there are scratches or dirt on the timing belt 12, at least a part of the black bars or white spaces of the barcode is missing, so the barcode cannot be read. In this case, the abnormality detection unit 36 may detect scratches or dirt on the timing belt 12. Since the scratches on the timing belt 12 may cause the timing belt 12 to break, detecting the scratches on the timing belt 12 can indicate a sign that the timing belt 12 may break.

[0038] Also, the abnormality detection unit 36 identifies the abnormal location of the timing belt 12 based on the comparison result output from the comparison unit 35. As shown in FIG. 5, when there is a portion where the values of the read signal and the comparison signal do not match during the low-level period TA and the high-level period TB, first, the position of this portion within the pseudo-random sequence is identified from the patterns before and after this portion. Here, the positional relationship between the position on the timing belt 12 and the position of the value of the pseudo-random sequence indicated by the barcode is predetermined, for example, when the home door device 10 is installed. Based on this positional relationship, the position on the timing belt 12 corresponding to the position within the identified pseudo-random sequence is identified. The identified position is the abnormal location where elongation or contraction has occurred in the timing belt 12.

[0039] Furthermore, the abnormality detection unit 36 determines the degree of abnormality of the timing belt 12 based on the comparison result output from the comparison unit 35. As shown in FIG. 5, when there is a portion where the values of the read signal and the comparison signal do not match during the low-level period TA and the high-level period TB, from the time width of this portion indicated by the comparison result, the time widths of the low-level period TA and the high-level period TB included in the reference signal and the corresponding low-level period TA and high-level period TB included in the read signal are respectively obtained. The larger the difference in this time width, the larger the amount of elongation of the timing belt 12. For example, when the difference in this time width is equal to or greater than the threshold value, the abnormality detection unit 36 determines that the degree of abnormality is high, and when it is less than the threshold value, it determines that the degree of abnormality is low. Here, it is assumed that the threshold value is the length corresponding to 10 sampling periods. In the example shown in FIG. 5, the difference in the time width of the low-level period TA and the difference in the time width of the high-level period TB are both the length corresponding to 1 sampling period. In this case, since the difference in the time width is less than the threshold value, the abnormality detection unit 36 determines that the degree of abnormality is low.

[0040] Note that the abnormality detection unit 36 may store the abnormality detection history in the storage unit 33. This abnormality detection history includes the date and time when the abnormality was detected, the abnormal location, and the degree of abnormality.

[0041] The notification unit 37 notifies the server device 40 of the abnormality detected by the abnormality detection unit 36. Specifically, when the abnormality detection unit 36 detects an abnormality, the notification unit 37 transmits notification information for notifying the abnormality to the server device 40. This notification information includes the abnormal location and the degree of abnormality.

[0042] Further, the notification unit 37 may issue different notifications depending on the degree of abnormality determined by the abnormality detection unit 36. For example, the notification information includes warning information and caution information. The warning information is information warning that there is a risk of failure. The caution information is information cautioning that there is a risk of failure. The warning information is information indicating that it requires more urgency than the caution information. For example, when the abnormality detection unit 36 determines that the degree of abnormality is high, the notification unit 37 transmits the warning information. On the other hand, when the abnormality detection unit 36 determines that the degree of abnormality is low, the notification unit 37 transmits the caution information.

[0043] Alternatively, the notification unit 37 may notify only the server device 40 of the abnormalities with a high degree of abnormality determined by the abnormality detection unit 36. For example, when an abnormality is detected by the abnormality detection unit 36 and it is determined that the degree of that abnormality is high, the notification unit 37 transmits the notification information to the server device 40. On the other hand, when an abnormality is detected by the abnormality detection unit 36 but it is determined that the degree of that abnormality is low, the notification unit 37 does not transmit the notification information to the server device 40.

[0044] When an abnormality is notified by the notification unit 37, for example, a plan for maintenance work to replace the timing belt 12 at the timing when the abnormality is detected is created, and the timing belt 12 is replaced by a maintenance staff. Also, the server device 40 may store the history of the notification information transmitted from a plurality of home door devices 10, and an analysis of the abnormality of the timing belt 12 may be performed using this history of the notification information. The analysis result may be fed back to the development of a new timing belt 12. For example, when the abnormal portions of the timing belt 12 are concentrated at specific positions such as the portion in contact with the pulley 13 in the closed state of the door 14 or the portion adjacent to the connecting member 16, it can be understood that that position is a position where an abnormality is likely to occur in the timing belt 12. In this case, for example, by changing the thickness or material of the position where an abnormality is likely to occur, the timing belt 12 may be improved to be less likely to develop an abnormality.

[0045] 2. Operation FIG. 6 is a flowchart showing an example of the operation of the abnormality detection system 1. When the operation of opening and closing the door 14 of the home door device 10 is started in step S101 (the determination in step S101 is YES), in step S102, the photosensor 20 reads the barcode on the timing belt 12 and generates a read signal. In step S103, the A / D conversion unit 31 converts this read signal into a digital signal. In step S104, the high-speed sampling unit 32 performs high-speed sampling on this read signal. In step S105, the comparison unit 35 compares the reference signal read from the storage unit 33 and generated by the waveform generation unit 34 with this read signal and outputs a comparison result. In step S106, the abnormality detection unit 36 detects an abnormality in the timing belt 12 based on this comparison result. At this time, the abnormality detection unit 36 also specifies the abnormal location and determines the degree of abnormality. If no abnormality in the timing belt 12 is detected (the determination in step S106 is NO), this process ends. On the other hand, if an abnormality in the timing belt 12 is detected (the determination in step S106 is YES), in step S107, the notification unit 37 notifies this abnormality to the server device 40.

[0046] According to the above-described embodiment, since an abnormality including elongation or contraction of the timing belt 12 is detected, the detection accuracy of a sign of failure of the timing belt 12 can be improved. Further, since the abnormal location of the timing belt 12 is specified, the position where the abnormality has occurred in the timing belt 12 can be recognized. Furthermore, when abnormalities occur at a plurality of locations in the timing belt 12, these abnormalities can be detected separately. Furthermore, since the degree of abnormality of the timing belt 12 is determined, the degree of abnormality that has occurred in the timing belt 12 can be recognized. Furthermore, since each of the read signal and the reference signal is Manchester encoded, even if the same value continues in the pseudo-random sequence, the abnormal location on the timing belt 12 can be accurately recognized. Furthermore, since the photosensor 20 reads the barcode at a position where tension is applied by the pulley 13 on the outer peripheral surface of the timing belt 12, the reading accuracy of the barcode is improved.

[0047] 3. Modification Examples The present invention is not limited to the above-described embodiments. The above-described embodiments may be modified as follows. Also, two or more of the following modification examples may be used in combination.

[0048] Modification Example 1 In the above-described embodiment, the method of fixing the barcode to the outer peripheral surface of the timing belt 12 is not limited to printing. For example, the barcode may be engraved on the surface of the timing belt 12 by irradiating the outer peripheral surface of the timing belt 12 with laser light. Also, when forming the timing belt 12, unevenness indicating the barcode may be formed on the outer peripheral surface of the timing belt 12. Further, a magnetic tape for recording the barcode may be attached to the outer peripheral surface of the timing belt 12. When a magnetic tape is used, a magnetic sensor for reading the magnetic tape may be used instead of the photosensor 20. The fixing mentioned here includes not only printing but also engraving, forming, and attaching a magnetic tape. Even with this modification example, it is possible to detect an abnormality including elongation and contraction of the timing belt 12.

[0049] Modification Example 2 In the above-described embodiment, the location where the barcode is fixed is not necessarily limited to the outer peripheral surface of the timing belt 12. For example, when the side surface of the timing belt 12 does not contact the pulley 13, the barcode may be fixed to the side surface of the timing belt 12. Even with this modification example, it is possible to detect an abnormality including elongation and contraction of the timing belt 12.

[0050] Modification Example 3 In the above-described embodiment, the reading device according to the present invention is not limited to the photosensor 20. As in the above-described modification example, a magnetic sensor may be used instead of the photosensor 20. Also, a camera and illumination for photography may be used instead of the photosensor 20. The camera photographs and reads the barcode. Even with this modification example, it is possible to detect an abnormality including elongation and contraction of the timing belt 12.

[0051] Modification Example 4 In the above-described embodiment, the barcode does not necessarily have different information depending on its position in the moving direction of the timing belt 12. For example, the barcode may indicate a sequence of numbers repeating a predetermined pattern. Since the door 14 operates in the same operation pattern, based on the time when a portion where the reference signal and the reading signal do not match is read and the moving speed of the timing belt 12, the moving distance of the timing belt 12 is obtained. Based on the reference position of the timing belt 12 at which the reading of the barcode is started by the photosensor 20 and this moving distance, an abnormal portion of the timing belt 12 is specified. Also by this modification example, an abnormal portion of the timing belt 12 can be specified.

[0052] Modification Example 5 In the above-described embodiment, the information carrier fixed to the timing belt 12 is not limited to a barcode. For example, the information carrier may be numbers, symbols, or the figures themselves. For example, numbers that are consecutive in order from 1 are printed along the moving direction of the timing belt 12. In this modification example, instead of the photosensor 20, a camera and illumination for photography are used, and the camera captures the sequence of numbers on the timing belt 12 to generate an image signal. Then, an abnormality of the timing belt 12 may be detected based on a comparison between the generated image signal and a reference image signal captured and generated at the time of installation of the home door device 10. Also, based on the positions of the respective numbers on the timing belt 12 determined at the time of installation of the home door device 10, an abnormal portion on the timing belt 12 is specified from the numbers including a portion where these image signals do not match. Also by this modification example, it is possible to detect an abnormality including elongation or contraction of the timing belt 12 and specify the abnormal portion.

[0053] Modification Example 6 In the above-described embodiments, the Manchester code does not necessarily have to be used. For example, when the pseudo-random sequence does not include a long sequence consisting of consecutive 0s or 1s, the pseudo-random sequence may be used without being Manchester-encoded. Even with this modification, it is possible to detect an abnormality including elongation or contraction of the timing belt 12.

[0054] Modification Example 7 In the above-described embodiments, a plurality of photo sensors 20 may be provided. For example, two photo sensors 20 may be provided, and one photo sensor 20 may be installed near the pulley 13b as shown in FIG. 1, and the other photo sensor 20 may be installed near the pulley 13a. According to this modification, it is possible to reduce a blind spot portion where an abnormality in the timing belt 12 is not detected.

[0055] Modification Example 8 In the above-described embodiments, the installation location of the photo sensor 20 is not limited to the vicinity of the pulley 13b. For example, the photo sensor 20 may be installed at a position facing the timing belt 12 near the pulley 13a. Further, as shown in FIG. 7, when a tension roller 17 that contacts the timing belt 12 and applies tension is provided between the pulley 13a and the pulley 13b, the photo sensor 20 may be installed at a position facing the timing belt 12 near the tension roller 17. The tension roller 17 is also included in the rotating member according to the present invention. Note that in FIG. 7, illustration of configurations other than the timing belt 12, the pulley 13, the tension roller 17, and the photo sensor 20 is omitted. According to this modification, since the photo sensor 20 reads the barcode at a position where tension is applied to the outer peripheral surface of the timing belt 12 by the tension roller 17, the reading accuracy of the barcode is improved.

[0056] Modification Example 9 In the above-described embodiment, the sampling frequency used for high-speed sampling is not limited to 10 times the original sampling frequency. The sampling frequency used for high-speed sampling may be determined according to the allowable range of the elongation amount of the timing belt 12. For example, if the sampling frequency used for high-speed sampling is set to 100 times the original sampling frequency, it is possible to detect the elongation or contraction of the timing belt 12 up to 1 / 10 of the length when it is set to 10 times. Thus, the higher the sampling frequency used for high-speed sampling, the more the resolution for detecting the elongation or contraction of the timing belt 12 can be improved. On the other hand, if the sampling frequency used for high-speed sampling is set to 5 times the original sampling frequency, it is only possible to detect the elongation or contraction of the timing belt 12 up to twice the length when it is set to 10 times. However, the smaller the sampling frequency, the lower the processing amount of sampling, so the manufacturing cost of the system can be reduced.

[0057] Modification Example 10 In the above-described embodiment, when the comparison unit 35 can distinguish and output three comparison results, i.e., the value of the read signal matches the value of the reference signal, the value of the read signal is greater than the value of the reference signal, and the value of the read signal is less than the value of the reference signal, the abnormality detection unit 36 may further distinguish and detect elongation and contraction. For example, as shown in FIG. 5, when elongation occurs in the timing belt 12, the time width of the low-level period or high-level period included in the read signal becomes larger than the time width of the corresponding period included in the reference signal. Therefore, a comparison result indicating that the value of the read signal is less than the value of the reference signal is output in a part of this period. When such a comparison result is output, the abnormality detection unit 36 detects the elongation of the timing belt 12. On the contrary, when contraction occurs in the timing belt 12, the time width of the low-level period or high-level period included in the read signal becomes smaller than the time width of the corresponding period included in the reference signal. Therefore, a comparison result indicating that the value of the read signal is greater than the value of the reference signal is output in a part of this period. When such a comparison result is output, the abnormality detection unit 36 detects the contraction of the timing belt 12. In this case, the notification information may include the type of the detected abnormality. According to this modification example, the type of abnormality occurring in the timing belt 12 can be recognized.

[0058] Modification Example 11 In the above-described embodiment, the abnormality detected by the abnormality detection unit 36 is not limited to the abnormality of the timing belt 12. For example, when problems such as stiffness, clogging, and oil depletion of the movable part included in the home door device 10 are linked to the abnormality of the timing belt 12, the operation of the part where these problems occur becomes slow, and the waveform of the read signal changes. Therefore, by comparing the read signal and the reference signal as in the above-described embodiment, it is also possible to detect the abnormality of the movable part included in the home door device 10. The abnormality related to the timing belt 12 includes, in addition to the abnormality of the timing belt 12, the abnormality of the part linked to the timing belt 12. According to this modification example, in addition to the abnormality of the timing belt 12, the abnormality of the part linked to the timing belt 12 can be recognized.

[0059] Modification Example 12 In the above-described embodiment, the notification unit 37 does not necessarily have to notify the server device 40 of an abnormality every time an abnormality is detected by the abnormality detection unit 36. For example, the notification unit 37 may notify the server device 40 of an abnormality only when an abnormality is continuously detected a predetermined number of times or more at the same position on the timing belt 12 by the abnormality detection unit 36. In other words, when the number of times an abnormality is continuously detected at the same position on the timing belt 12 by the abnormality detection unit 36 is less than the predetermined number of times, the notification unit 37 does not notify the server device 40 of the abnormality. According to this modification, only highly accurate abnormalities can be notified.

[0060] Further, the notification unit 37 may notify the server device 40 of an abnormality only when the number of abnormal locations detected by the abnormality detection unit 36 is equal to or greater than a predetermined number. In other words, when the number of abnormal locations detected by the abnormality detection unit 36 is less than the predetermined number, the notification unit 37 does not notify the server device 40 of the abnormality. According to this modification, only serious abnormalities can be notified.

[0061] Furthermore, the notification unit 37 may notify the server device 40 of an abnormality only when the amount of change in the abnormality detected by the abnormality detection unit 36 is equal to or greater than a predetermined amount. In other words, when the amount of change in the abnormality detected by the abnormality detection unit 36 is less than the predetermined amount, the notification unit 37 does not notify the server device 40 of the abnormality. This amount of change includes the amount of change in the degree of abnormality and the amount of change in the number of abnormal locations. According to this modification, only serious abnormalities can be notified.

[0062] Furthermore, when an area where an abnormality is likely to occur is specified by analyzing the notification information, the notification unit 37 may notify the abnormality differently between the area where the abnormality is likely to occur and other areas. For example, when the abnormal location is not an area where an abnormality is likely to occur as specified in advance, the notification unit 37 notifies the server device 40 of the abnormality only when the degree of abnormality is high. On the other hand, when the abnormal location is an area where an abnormality is likely to occur as specified in advance, the notification unit 37 notifies the server device 40 of the abnormality regardless of the degree of abnormality. According to this modification, the abnormality in the area where an abnormality is likely to occur can be preferentially notified.

[0063] Modification Example 13 In the above-described embodiment, the operation of detecting an abnormality in the timing belt 12 does not necessarily have to be performed every time the door 14 of the home door device 10 opens and closes. For example, the operation of detecting an abnormality in the timing belt 12 may be performed only once a day. Further, the door 14 of the home door device 10 basically operates according to a predetermined operation pattern, but in the case where a person is pinched by the door 14 or the like, an exception operation different from the predetermined operation pattern may be performed. When such an exception operation is performed, a signal indicating the exception operation is supplied from the control device 15 to the state management device 30. When receiving this signal, the state management device 30 discards, for example, the reading signal generated by the photosensor 20 and does not perform the operation of detecting an abnormality in the timing belt 12. According to this modification example, the load of the process of detecting an abnormality in the timing belt 12 can be reduced.

[0064] Modification Example 14 In the above-described embodiment, the destination of the abnormality notification is not limited to the server device 40. For example, when the control device 15 is connected to a comprehensive control device that manages a plurality of home door devices 10, the notification unit 37 may notify the comprehensive control device of the abnormality via the control device 15. According to this modification example, even if the state management device 30 itself does not have a communication function with an external device, the server device 40 can be notified of the abnormality.

[0065] Modification Example 15 In the above-described embodiment, the server device 40 may store the history of the notification information received from a plurality of home door devices 10 and analyze the locations where abnormalities are likely to occur using this history of the notification information. Artificial intelligence may be used for this analysis. According to this modification example, it is possible to recognize the locations where abnormalities are likely to occur in the timing belt 12.

[0066] Modification Example 16 In the above-described embodiment, the abnormality detection system 1 may be applied to the detection of abnormalities in belts for power transmission other than the timing belt 12 of the home door device 10. For example, the belt for power transmission may be a belt used for other purposes, such as a timing belt used for a vehicle engine, a conveyor belt used for transporting articles, a belt used for a machine tool, etc. Further, the belt for power transmission is not limited to a timing belt, and may be a belt other than a timing belt. Furthermore, the belt for power transmission is not limited to a toothed belt. For example, the belt for power transmission may be a V-belt. Furthermore, the belt for power transmission is not limited to one that rotates and moves in both left and right directions, and may be one that rotates in one direction. Furthermore, the belt for power transmission is not limited to an endless belt, and may be an end belt. In the case of an end belt, winding devices are provided at one end and the other end of the belt, respectively, and the belt moves by one winding device feeding out the belt and the other winding device winding up the belt.

[0067] Modification Example 17 In the above-described embodiment, since the barcode has different information depending on its position in the moving direction of the timing belt 12, the state management device 30 can specify the position of the door 14 based on the read signal. Therefore, the state management device 30 may be used to specify the position of the door 14 instead of the encoder provided on the pulley 13. According to this modification example, the position of the door 14 can be specified without providing an encoder.

[0068] Modification Example 18 In the above-described embodiment, the configuration of the abnormality detection system 1 is not limited to the above-described example. The abnormality detection system 1 may be configured to include one or more of the above-described devices, or may be configured without including some of the devices.

[0069] In the above-described embodiment, at least a part of the functions of the state management device 30 may be realized by a circuit such as a DSP (Digital Signal Processor), an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA (Field Programmable Gate Array).

[0070] Modification Example 19 In the above-described embodiment, the operation of the abnormality detection system 1 is not limited to the above-described example. The processing procedure of the abnormality detection system 1 may be reordered as long as there is no contradiction. Also, some of the processing procedures of the abnormality detection system 1 may be omitted.

[0071] Modification Example 20 Another aspect of the present invention may provide a method having steps of processing performed in the abnormality detection system 1. Further, still another aspect of the present invention may provide a program executed in the state management device 30. This program may be provided by being stored in a computer-readable recording medium, or may be provided by being downloaded via the Internet or the like.

Explanation of Reference Numerals

[0072] 1: Abnormality detection system, 10: Home door device, 11: Housing, 12: Timing belt, 13: Pulley, 13a: Pulley, 13b: Pulley, 14: Door, 15: Control device, 16: Connecting member, 17: Tension roller, 20: Photo sensor, 30: State management device, 31: A / D conversion unit, 32: High-speed sampling unit, 33: Storage unit, 34: Waveform generation unit, 35: Comparison unit, 36: Abnormality detection unit, 37: Notification unit, 40: Server device, T: Sampling frequency, TA: Low-level period, TB: High-level period

Claims

1. A state management device that detects an abnormality related to the belt based on a comparison result between a signal generated by reading an information holding body fixed to the surface of a power transmission belt with a reading device and a reference signal, The information holding body having different information depending on the position in the driving direction of the belt is fixed to the surface of the belt, The state management device identifies an abnormal portion of the belt based on the comparison result An abnormality detection system.

2. Each of the signal generated by the reading device and the reference signal is a signal of the same pseudo-random sequence having an autocorrelation value of 1 and a cross-correlation value of 0 The abnormality detection system according to claim 1.

3. Each of the signal generated by the reading device and the reference signal is a signal obtained by Manchester-encoding the pseudo-random sequence The abnormality detection system according to claim 2.

4. The belt is a toothed belt The abnormality detection system according to any one of claims 1 to 3.

5. The belt rotates and moves as the rotating member that contacts the belt and applies tension rotates, and the reading device reads the information holding body in the vicinity of the rotating member The abnormality detection system according to any one of claims 1 to 4.

6. The state management device detects elongation or contraction of the belt based on a difference in the time axis direction between the waveform of the signal generated by the reading device and the waveform of the reference signal The abnormality detection system according to any one of claims 1 to 5.

7. Each of the signal generated by the reading device and the reference signal has a pulse waveform, The state management device detects the elongation or contraction of the belt based on a comparison result between the time width of a high-level period or a low-level period included in the signal generated by the reading device and the time width of the corresponding period included in the reference signal. The abnormality detection system according to claim 6.

8. Each of the signal generated by the reading device and the reference signal has a pulse waveform. The state management device determines the degree of the abnormality based on a difference between the time width of a high-level period or a low-level period included in the signal generated by the reading device and the time width of the corresponding period included in the reference signal. The abnormality detection system according to any one of claims 1 to 7.

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