GB2578031A

GB2578031A - Position detection system

Info

Publication number: GB2578031A
Application number: GB1918547.9A
Authority: GB
Inventors: Nishio Miki; Fukuhara Yuki; Togano Takeshi; HAYASHIDA Takashi; MATSUSHITA Hironobu
Original assignee: Mitsubishi Electric Engineering Co Ltd
Current assignee: Mitsubishi Electric Engineering Co Ltd
Priority date: 2017-06-28
Filing date: 2017-06-28
Publication date: 2020-04-15
Also published as: JPWO2019003340A1; CN110832413A; WO2019003340A1; GB201918547D0

Abstract

The present invention comprises: a vibration detection unit (1) that is attached to a mobile body (12), the vibration detection unit (1) detecting vibration and transmitting a signal that has vibration information and identification information indicating the detected vibration; a transmitter (2) that is attached to the mobile body (12), the transmitter (2) periodically transmitting a signal that has the identification information; a plurality of receivers (3) that receive the signals; an identification unit (402) that identifies, from the identification information possessed by the signals received by the receiver (3), the source from which the signals were transmitted; a position detection unit (403) that detects, from the reception strength of the signals received by the receiver (3) and the identification results obtained from the identification unit (402), the position of the transmitter (2) that is the source from which the signals were transmitted; and a work status detection unit (404) that detects, from the vibration information possessed by the signals received by the receiver (3), the identification results obtained from the identification unit (402), and the detection results obtained from the position detection unit (403), the work status with respect to the mobile body (12) to which the vibration detection unit (1) that is the source from which the signals were transmitted is attached, or a work object (11) disposed on the mobile body (12).

Description

DESCRIPTION

TITLE OF INVENTION: POSITION DETECTION SYSTEM

TECHNICAL FIELD

[0001] The present invention relates to a position detection system that detects the position of a movable body on which a work object is placed, and detects a work state for the movable body or the work object placed on the movable body.

BACKGROUND ART

[0002] In related art, a device disclosed in Patent Literature 1, for example, is known as a device that detects the position of a worker. The device disclosed in Patent Literature I detects the position of a worker by using an ultrasonic transmitter mounted on a helmet of the worker and an ultrasonic receiver installed on an industrial vehicle.

CITATION LIST

PATENT LITERATURE

[0003] Patent Literature 1 Japanese Patent Application Laid-Open Publication No.: 2010-20548

SUMMARY OF INVENTION

TECHNICAL PROBLEM

[0004] The device disclosed in Patent Literature 1, however, has a problem in that the states work carried out by workers cannot be detected. In addition, the device disclosed in Patent Literature I has a problem in that a great burden is imposed on the workers because ultrasonic transmitters are mounted on the helmets of the workers [0005] The present invention has been made to solve such problems as described above, and an object thereof is to provide a position detection system capable of detecting the work state without imposing a burden on a worker.

SOLUTION TO PROBLEM

[0006] A position detection system according to the present invention includes: a vibration detecting unit mounted on a movable body on which a work object is placed, for detecting vibration and transmitting a signal containing vibration information representing the detected vibration and identification information; a transmitter mounted on the movable body, for periodically transmitting a signal containing identification information; a plurality of receivers for receiving signals; an identification unit for identifying a transmission source of a signal received by each receiver on the basis of identification information contained in the signal; a position detecting unit for detecting a position of the transmitter that is the transmission source of the signal received by each receiver on the basis of reception strength of the signal and a result of identification performed by the identification unit; and a work state detecting unit for detecting a work state for the movable body on which the vibration detecting unit that is the transmission source of the signal received by each receiver is mounted or on the work object placed on the movable body on the basis of the vibration information contained in the signal, the result of identification performed by the identification unit, and a result of detection performed by the position detecting unit.

ADVANTAGEOUS EFFECTS OF INVENTION

[0007] According to the present invention, the configuration as described above allows detection of a work state without imposing a burden on a worker.

BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a diagram illustrating an example configuration of a position detection system according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an example configuration of a controller according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating an example arrangement in a production site to which the position detection system according to the first embodiment of the present invention is applied.

FIG. 4 is a flowchart illustrating example operation of the position detection system according to the first embodiment of the present invention FIG. 5 is a chart illustrating an example of a result of reception of a receiver in the first embodiment of the present invention FIG. 6 is a diagram illustrating example operation of the position detection system according to the first embodiment of the present invention.

FIG. 7 is a table explaining a case in which the work state is detected on the basis of a vibration pattern in the position detection system according to the first embodiment of the present invention.

FIG. 8 is a table explaining a case in which the work state is detected on the basis of a vibration pattern and in which vibration patterns are registered for each process in the position detection system according to the first embodiment of the present invention.

FIG. 9 is a table explaining a case in which the work state is detected on the basis of a vibration pattern and in which vibration patterns in each process are changed in the position detection system according to the first embodiment of the present invention.

FIG. 10 is a diagram illustrating an example configuration of a transmitting side in a position detection system according to a second embodiment of the present invention.

FIG. 11 is a diagram illustrating an example configuration of a controller according to the second embodiment of the present invention.

FIG. 12 is a flowchart illustrating example operation of the position detection system according to the second embodiment of the present invention.

FIG. 13 is a diagram illustrating an example configuration of a transmitting side in a position detection system according to a third embodiment of the present invention.

FIG. 14 is a diagram illustrating an example configuration of a controller according to the third embodiment of the present invention FIGS. 15A and 15B are diagrams illustrating example hardware configurations of a controller according to the first to fourth embodiments of the present invention.

DESCRIPTION OF EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First Embodiment FIG. 1 is a diagram illustrating an example configuration of a position detection system according to a first embodiment of the present invention.

The position detection system detects the position of a wheeled platform (movable body) 12 on which a work object 11 (see FIG. 6, etc.) such as a product is placed, and detects a work state, carried out by a worker, on the wheeled platform 12 or the work object 11 placed on the wheeled platform 12, at a production site. Note that one or more wheeled platforms 12 are used at a production site. As illustrated in FIG. I, the position detection system includes a vibration detecting unit 1, a transmitter 2, a plurality of receivers 3, and a controller 4 In the example of FIG. 1, two receivers 3 are illustrated.

[0010] The vibration detecting unit 1 is mounted on the wheeled platform 12 and detects vibration. In addition, each time vibration is detected, the vibration detecting unit I transmits a signal containing vibration information representing the detected vibration and identification information for identifying the vibration detecting unit 1 outward. Note that the signal transmitted by the vibration detecting unit I is set to have a high radio field strength so that the receivers 3 do not fail to receive the signal An example of the vibration detecting unit 1 is a vibration sensor.

[0011] The transmitter 2 is mounted on the wheeled platform 12, and periodically (every 0.5 seconds, for example) transmits a signal containing identification information for identifying the transmitter 2 outward.

[0012] The receivers 3 receive signals. The receivers 3 are arranged for respective processes at the production site, for example.

[0013] The controller 4 processes results of reception of the receivers 3. As illustrated in FIG. 2, the controller 4 includes a storage unit 401, an identification unit 402, a position detecting unit 403, and an work state detecting unit 404 [0014] The storage unit 401 stores the identification information of the vibration detecting unit 1 and the identification information of the transmitter 2. The storage unit 401 also stores association between the vibration detecting unit 1 and the transmitter 2. The storage unit 401 may be a nonvolatile or volatile semiconductor memory such as a random access memory (RAM), a read only memory (ROM), a flash memory, an erasable programmable ROM (EPROM), or an electrically EPROM (EEPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disc, or a digital versatile disc (DVD), for example.

[0015] The identification unit 402 identifies the source of transmission of a signal received by a receiver 3 on the basis of the identification information contained in the signal. In this process, the identification unit 402 identifies the source of transmission of the signal received by the receiver 3 by comparing the identification information contained in the signal with the identification information stored in the storage unit 401. [0016] The position detecting unit 403 detects the position of the transmitter 2 that is the source of transmission of the signal received by the receiver 3 on the basis of the reception strength of the signal and the result of identification performed by the identification unit 402. In this process, the position detecting unit 403 first determines, among the receivers 3, a receiver 3 that received the signal having the highest reception strength, from the transmitter 2 that is an object identified by the identification unit 402. The position detecting unit 403 then detects the area (the process, for example) in which the determined receiver 3 is located as the position of the transmitter 2.

[0017] The work state detecting unit 404 detects the state of work, which is being carried out by the worker, on the wheeled platform 12 mounted with the vibration detecting unit 1, which is the transmission source of the signal received by the receiver 3, or on the work object 11 placed on the wheeled platform 12 on the basis of the vibration information contained in the signal, the result of identification performed by the identification unit 402, and the result of detection performed by the position detecting unit 403. In this process, the work state detecting unit 404 detects the work state on the basis of the vibration information contained in the signal from the vibration detecting unit 1 to be detected, which is identified by the identification unit 402, and the position of the transmitter 2 mounted on the same wheeled platform 12 as that on which the vibration detecting unit 1 is mounted.

[0018] Next, example operation of the position detection system according to the first embodiment will be explained with reference to FIGS. 3 to 5.

Hereinafter, assume that the production line system at the production site is a cell manufacturing system. At the production site, a plurality of processes (cells) is provided as illustrated in FIG. 3, for example. In addition, one or more workers are arranged for one or more processes, and carry out work on the work object 11 placed on the wheeled platform 12. Note that no worker is arranged and no work is carried out for some processes. The stop position of the wheeled platform 12 is determined for each process. The wheeled platform 12 may be moved to a next process by a worker who carried out work in a previous process, or may be taken from a previous process by a worker who carries out work in a next process. After the wheeled platform 12 is stopped at a stop position, a worker sets a part, when the part needs to be attached, and takes a tool to carry out work. Some workers carry out work without moving and others carry out work while moving around the wheeled platform 12.

[0019] Note that the storage unit 401 stores in advance the identification information of the vibration detecting unit 1 and the identification information of the transmitter 2, and the association between the vibration detecting unit 1 and the transmitter 2. A set of vibration detecting unit 1 and the transmitter 2 is mounted on the wheeled platform 12. For example, two vibration sensors having functions of vibration detection and position beacons can be used as the set of vibration detecting unit 1 and the transmitter 2. The vibration detecting unit 1 detects vibration, and transmits a signal containing vibration information representing the detected vibration and the identification information outward. In addition, the transmitter 2 periodically transmits a signal containing the identification information outward. The receivers 3 are arranged for respective processes and receive signals.

[0020] In the controller 4, as illustrated in FIG. 4, the identification unit 402 first identifies the source of transmission of a signal received by a receiver 3 on the basis of the identification information contained in the signal (step ST401). In this process, the identification unit 402 identifies the source of transmission of the signal received by the receiver 3 by comparing the identification information contained in the signal with the identification information stored in the storage unit 401.

[0021] Subsequently, the position detecting unit 403 detects the position of the transmitter 2 that is the source of transmission of the signal received by the receiver 3 on the basis of the reception strength of the signal and the result of identification performed by the identification unit 402 (step ST402). In this process, the position detecting unit 403 first determines, among the receivers 3, a receiver 3 that received the signal having the highest reception strength, from the transmitter 2 that is an object identified by the identification unit 402. The position detecting unit 403 then detects the process for which the determined receiver 3 is arranged as the position of the aforementioned transmitter 2.

As described above, the transmitter 2 that periodically transmits a signal is mounted on the wheeled platform 12, and a plurality of receivers 3 is arranged in the production site, which enables the controller 4 to detect the position of the transmitter 2 on the basis of the reception strengths of the signals received by the receivers 3. The controller 4 is thus capable of detecting the position of the wheeled platform 12 on which the transmitter 2 is mounted. The controller 4 is also capable of instructing a worker to start working by a display (screen display, light, or the like), audio, or the like when the wheeled platform 12 is determined to have stopped at a stop position of a process [0022] In addition, the work state detecting unit 404 detects the state of work, which is being carried out by the worker, on the wheeled platform 12 mounted with the vibration detecting unit 1, which is the transmission source of the signal received by the receiver 3, or on the work object 11 placed on the wheeled platform 12 on the basis of the vibration information contained in the signal, the result of identification performed by the identification unit 402, and the result of detection performed by the position detecting unit 403 (step ST403). In this process, the work state detecting unit 404 detects the work state on the basis of the vibration information contained in the signal from the vibration detecting unit 1 to be detected, which is identified by the identification unit 402, and the position of the transmitter 2 mounted on the same wheeled platform 12 as that on which the vibration detecting unit 1 is mounted.

As described above, the vibration detecting unit 1 that detects vibration is mounted on the wheeled platform 12, which enables the controller 4 to detect the work state (whether or not the wheeled platform 12 is moved or whether or not work on the work object 11 placed on the wheeled platform 12 is carried out) on the basis of the vibration detected by the vibration detecting unit 1 and the result of detection performed by the position detecting unit 403.

[0023] FIG. 5 illustrates a result of reception of a signal by a receiver 3 arranged for a specific process. In FIG. 5, the horizontal axis represents time, and the vertical axis represents reception strength. In addition, in FIG. 5, reference numeral "501" represents a signal transmitted by the transmitter 2 mounted on a specific wheeled platform 12, reference numeral "502-represents vibration (acceleration) in the x axis direction detected by the vibration detecting unit 1 mounted on the specific wheeled platform 12, reference numeral "503" represents vibration (acceleration) in the y axis direction detected by the vibration detecting unit 1, and reference numeral "504" represents vibration (acceleration) in the z axis direction detected by the vibration detecting unit 1.

[0024] In FIG. 5, during a time zone 505, because the reception strength of a signal 501 received by the receiver 3 is low, the position detecting unit 403 determines that the specific wheeled platform 12 is not position at the specific process. In addition, during the time zone 505, vibrations 502 to 504 are detected by the vibration detecting unit 1. Thus, the work state detecting unit 404 determines that the wheeled platform 12 is being moved on the basis of the result of detection performed by the position detecting unit 403 and the vibrations 502 to 504.

In contrast, during a time zone 506, because the reception strength of the signal 501 received by the receiver 3 is high, the position detecting unit 403 determines that the specific wheeled platform 12 is positioned at the specific process. In addition, during the time zone 506, vibrations 502 to 504 are detected by the vibration detecting unit I Thus, the work state detecting unit 404 determines that work on the work object 11 placed on the wheeled platform 12 is being carried out on the basis of the result of detection performed by the position detecting unit 403 and the vibrations 502 to 504.

[0025] In addition, as illustrated in FIG 5, the reception strength of the signal 501 changes during the time zone 505 during which the wheeled platform 12 is being moved, whereas the reception strength of the signal 501 is substantially constant during the time zone 506 during which the wheeled platform 12 is stopped. Thus, the work state detecting unit 404 may detect the work state considering the change in the reception strength of the signal 501.

[0026] The controller 4 then performs progress management at the production site on the basis of the position of the wheeled platform 12 detected by the position detecting unit 403 and the work state for the wheeled platform 12 or the work object 11 placed on the wheeled platform 12, which is detected by the work state detecting unit 404. [0027] FIG. 6 illustrates a case in which the controller 4 uses receivers 3-1 to 3-4 arranged in the first to fourth processes, respectively, to detect the states of work on three wheeled platforms 12-1 to 12-3 or on work objects 11 placed on the wheeled platforms 12-1 to 12-3. The upper part of FIG. 6 illustrates the positional relation of the receivers 3-1 to 3-4 and the wheeled platforms 12-1 to 12-3, and the states of work on the wheeled platforms 12-1 to 12-3 or on the work objects 11 placed on the wheeled platforms 12-1 to 12-3. The lower part of FIG. 6 illustrates results of reception of signals by the receivers 3-1 to 3-4.

In FIG. 6, the receiver 3-1 arranged for the first process and the receiver 3-2 arranged for the second process receive a signal containing vibration information representing the vibration detected by the vibration detecting unit 1 and a signal transmitted by the transmitter 2, which are mounted on the wheeled platform 12-1 The reception strength of the signal from the transmitter 2 becomes gradually lower at the receiver 3-1, while the reception strength of the signal from the transmitter 2 becomes gradually higher at the receiver 3-2. Specifically, the results of reception of the receivers 3-1 and 3-2 indicate that vibration is detected by the vibration detecting unit 1 mounted on the wheeled platform 12-1 and that the wheeled platform 12-1 is moving away from the receiver 3-1 and approaching the receiver 3-2. The controller 4 thus determines that the wheeled platform 12-1 is moving from the first process side toward the second process side.

[0028] In addition, in FIG. 6, the receiver 3-3 arranged for the third process and the receiver 3-4 arranged for the fourth process receive a signal containing vibration information representing the vibration detected by the vibration detecting unit 1 and a signal transmitted by the transmitter 2, which are mounted on the wheeled platform 122. The reception strengths of the signal from the transmitter 2 at the receivers 3-3 and 3-4 do not change, and the reception strength of the signal at the receiver 3-3 is higher than that at the receiver 3-4. Specifically, the results of reception of the receivers 3-3 and 3-4 indicate that the vibration is detected by the vibration detecting unit 1 mounted on the wheeled platform 12-2 and that the wheeled platform 12-2 is close to the receiver 3-3 but is far from the receiver 3-4. The controller 4 thus determines that work on the work object 11 placed on the wheeled platform 12-2 is being carried out in the third process [0029] In addition, in FIG. 6, the receiver 3-4 arranged for the fourth process receives a signal transmitted by the transmitter 2 mounted on the wheeled platform 12-3 with a high reception strength. The receiver 3-4 receives no signal from the vibration detecting unit 1 mounted on the wheeled platform 12-3. Specifically, the result of reception of the receiver 3-4 indicates that no vibration is detected by the vibration detecting unit 1 mounted on the wheeled platform 12-3 and that the wheeled platform 12-3 is close to the receiver 3-4. The controller 4 thus determines that the wheeled platform 12-3 is stopped at the fourth process.

[0030] As described above, according to the first embodiment, the vibration detecting unit 1 mounted on the wheeled platform 12, for detecting vibration and transmitting a signal containing vibration information representing the detected vibration and identification information, the transmitter 2 mounted on the wheeled platform 12, for periodically transmitting a signal containing identification information, a plurality of receivers 3 for receiving signals, the identification unit 402 for identifying the transmission source of a signal received by a receiver 3 on the basis of the identification information contained in the signal, the position detecting unit 403 for detecting the position of the transmitter 2 that is the transmission source of the signal received by the receiver 3 on the basis of the reception strength of the signal and the result of identification performed by the identification unit 402, and the work state detecting unit 404 for detecting the work state for the wheeled platform 12 on which the vibration detecting unit 1 that is the transmission source of the signal received by the receiver 3 or on the work object 11 placed on the wheeled platform 12 on the basis of the vibration information contained in the signal, the result of identification performed by the identification unit 402, and the result of detection performed by the position detecting unit 403 are provided, which enables detection of work states. In addition, because the vibration detecting unit 1 and the transmitter 2 are mounted on the wheeled platform 12, the burden imposed on the worker is reduced as compared with the related art.

[0031] The case in which the production line system at the production site is a cell manufacturing system and in which the wheeled platform 12 is used as the movable body is described above, however, it is limited to this, and the movable body may be anything on which a work object 11 is placed. For example, the position detection system according to the first embodiment is also applicable to a case where the production line system is a line production system and in which a conveyor belt is used as the movable body.

[0032] In addition, the case in which the position detecting unit 403 determines, among the receivers 3, a receiver 3 that received the signal having the highest reception strength, from the transmitter 2 that is an object identified by the identification unit 402, and detects the area in which the determined receiver 3 is located as the position of the transmitter 2 is described above; however, it is limited to this, and the position detecting unit 403 may detect the position of the transmitter 2 on the basis of a difference between reception strengths of the signal from the transmitter 2 at the receivers 3. In this manner, position detection using a plurality of receivers 3 enables more specific position detection in the area [0033] In addition, the case in which the work state detecting unit 404 detects the work state by using the presence/absence of vibration represented by the vibration information contained in the signal received by the receiver 3 is described above; however, it is limited to this, and the work state detecting unit 404 may detect the work state by machine learning by using the pattern of vibration represented by the vibration information contained in the signal received by the receiver 3, for example. In this case, the work state detecting unit 404 performs in advance machine learning of vibration patterns from vibration detected by the vibration detecting unit 1 when corresponding work is carried out by a manager (a team leader or the like at the production site). This enables the work state detecting unit 404 to detect the content of work on the work object 11.

[0034] Note that a plurality of works is normally carried out in each processes at a production site. Thus, the work state detecting unit 404 detects the states of works by using an enormous number of vibration patterns. For example, FIG. 7 illustrates a case in which a plurality of (first to ninth) processes is present and a total of 45 works are performed, and in which the work state detecting unit 404 detects the work state by using 45 vibration patterns in each process. In this case, the processing at the work state detecting unit 404 takes a long time.

[0035] Thus, in such a case, contents of works performed in each process and corresponding vibration patterns are registered in advance in association with each other in the work state detecting unit 404. This can reduce the number of vibration patterns used in the respective processes, and shortens the processing at the work state detecting unit 404. An example illustrated in FIG. 8 shows a case in which the contents of three works performed in the first process and corresponding vibration patterns are registered in association with each other in the work state detecting unit 404.

[0036] In addition, the contents of works in each process and vibration patterns registered in the work state detecting unit 404 may be changed. This enables a work to be carried out in a process to be changed to a work to be carried out in another process depending on the workload on each day. An example illustrated in FIG. 9 shows a case in which the 45th work (thread fastening of a compressor) to be carried out in the first process is changed to be carried out in the second process.

[0037] Second Embodiment.

In the first embodiment, the case in which the set of vibration detecting unit 1 and the transmitter 2 are mounted on the wheeled platform 12, so that the position detecting unit 403 detects the position of the wheeled platform 12 and the work state detecting unit 404 detects the work state for the wheeled platform 12 or on the work object 11 placed on the wheeled platform 12 is presented.

In the meantime, methods of mounting a vibration detecting unit on a tool and detecting whether or not a work is successfully carried out has been known in the related art (refer to patent Literatures 2 and 3, for example). With these technologies of the related art, however, whether or not a worker is working at a correct work position cannot be detected. Thus, a method for solving this will be described below.

Patent Literature 2: Japanese Patent Application Laid-Open Publication No.: 2000-117357 Patent Literature 3: Japanese Patent Application Laid-Open Publication No.: 2012-139766 [0038] FIG. 10 is a diagram illustrating an example configuration of a transmitting side (functional units excluding receivers 3 and a controller 4) in a position detection system according to a second embodiment of the present invention, and FIG. 11 is a diagram illustrating an example configuration of the controller 4 in the second embodiment of the present invention. The position detection system according to the second embodiment illustrated in FIGS. 10 and 11 additionally includes a plurality of vibration detecting units (second vibration detecting units) lb and a work position determining unit 405 as compared with the position detection system according to the first embodiment illustrated in FIGS. 1 and 2. The other components are similar and represented by the same reference numerals Description will be provided only the difference.

[0039] A plurality of vibration detecting units lb is mounted on a work object 11 and detect vibration. Each time vibration is detected, the vibration detecting units lb each transmit a signal containing vibration information representing the detected vibration and identification information for identifying the vibration detecting unit lb outward. Note that the signals transmitted by the vibration detecting units lb are set to have a high radio field strength so that the receivers 3 do not fail to receive the signals. An example of the vibration detecting units lb is vibration sensors. In the example of FIG. 10, two vibration detecting units lb are illustrated.

[0040] Note that the storage unit 401 stores the identification information of each of the vibration detecting unit 1, the vibration detecting units lb, and the transmitter 2, and the association between the vibration detecting unit 1, the vibration detecting units lb, and the transmitter 2.

[0041] The work position determining unit 405 determines whether or not the work position for the work object 11, on which the vibration detecting unit lb that is the transmission source of a signal received by a receiver 3 is mounted, is correct on the basis of the vibration information contained in the signal, the result of identification performed by the identification unit 402, and the result of detection performed by the position detecting unit 403. The work position determining unit 405 performs the determination by machine learning. In this process, the work position determining unit 405 determines whether or not the work position for the work object 11 is correct, on the basis of the vibration information contained in the signal from the vibration detecting unit lb subjected to the determination, which is identified by the identification unit 402, and the position of the transmitter 2 mounted on the wheeled platform 12 on which the vibration detecting unit lb is mounted. Note that the work position determining unit 405 performs in advance machining learning of vibration patterns from vibrations detected by the vibration detecting units lb when work is carried out at the correct work position and when work is carried out at an incorrect work position by a manager (a team leader of the like at the production site).

[0042] Next, example operation of the position detection system according to the second embodiment will be explained with reference to FIG. 12.

In the position detection system according to the second embodiment, as illustrated in FIG. 12, the controller 4 first detects a work on the work object 11 on the basis of a signal received by a receiver 3 (step ST1201). The process in step ST1201 is achieved by the processes illustrated in FIG. 4.

[0043] Subsequently, the work position determining unit 405 determines the work position for the work object 11, on which the vibration detecting unit lb that is the transmission source of a signal received by a receiver 3 is mounted, on the basis of the vibration information contained in the signal, the result of identification performed by the identification unit 402, and the result of detection performed by the position detecting unit 403 (step ST1202).

[0044] Subsequently, the work position determining unit 405 determines whether the work position is correct (step ST1203). When the work position determining unit 405 determines that the work position is correct in step ST1203, the sequence is terminated. Thereafter, the work position determining unit 405 proceeds to work position determination of the next work.

When the work position determining unit 405 determines that the work position is incorrect in step ST1203, notification of the same is provided to the outside by display, audio, or the like.

[0045] Because a plurality of vibration detecting units lb for detecting vibration is mounted on the work object 11 as described above, when a worker carried out thread fastening by on the work object 11 by using a driver, for example, the work position determining unit 405 can determine whether or not the position of the thread fastening is correct on the basis of combination of vibration patterns detected by the vibration detecting units lb. In addition, for work requiring accuracy, the work is repeated a plurality of times in advance and the work position determining unit 405 performs machine learning of the vibration pattern, which enables the vibration pattern to be standardized. [0046] As described above, according to the second embodiment, the vibration detecting units lb mounted on the work object II, for detecting vibration and transmitting a signal containing vibration information representing the detected vibration and identification information, and the work position determining unit 405 for determining whether the work position for the work object 11 on which the vibration detecting unit lb that is the transmission source of a signal received by a receiver 3 is mounted correct on the basis of the bration information contained in the signal, the result of identification performed by the identification unit 402, and the result of detection performed by the position detecting unit 403 are provided, which enables detection of whether or not a worker is working at a correct work position in addition to the effects produced in the first embodiment.

[0047] Note that the case in which the work position determining unit 405 determines whether or not a work position is correct is presented above, however, it is limited to this, and the work position determining unit 405 may determine whether or not the number of works or the order of works is correct in addition to the above.

[0048] Third Embodiment.

In the first embodiment, the case in which the transmitter 2 is mounted on the wheeled platform 12, a plurality of receivers 3 is arranged in a production site, and the position detecting unit 403 detects the position of the transmitter 2 on the basis of the reception strengths of signals received by the receivers 3 is presented. In contrast, in the third embodiment, a sheet-like irregular part 5 is provided on the ground on which the wheeled platform 12 moves, and a method by which a position detecting unit 403b detects the position of the wheeled platform 12 on the basis of a pattern of vibration generated when the wheeled platform 12 moves on the irregular part 5 will be explained.

FIG. 13 is a diagram illustrating an example configuration of a transmitting side (functional units excluding receivers 3 and a controller 4) in a position detection system according to the third embodiment of the present invention, and FIG. 14 is a diagram illustrating an example configuration of the controller 4 in the third embodiment of the present invention In the position detection system according to the third embodiment illustrated in FIGS. 13 and 14, the transmitter 2 is eliminated, the irregular part 5 is added, and the position detecting unit 403 is replaced with a position detecting unit 403b as compared with the position detection system according to the first embodiment illustrated in FIGS. 1 and 2. In addition, a plurality of receivers 3 may be replaced with a single receiver 3 The other components are similar and represented by the same reference numerals, and description thereof will not be repeated. [0049] The irregular part 5 is a sheet member having an irregular pattern and arranged on the ground on which the wheeled platform 12 moves. The irregular pattern is a pattern with which the position of the wheeled platform 12 can be identified.

[0050] The position detecting unit 403b detects the position of the vibration detecting unit 1 that is the transmission source of a signal received by the receiver 3 on the basis of vibration information contained in the signal and the result of identification performed by the identification unit 402. The position detecting unit 403b performs the detection by machine learning. In this process, the position detecting unit 403b detects the position of the vibration detecting unit 1 on the basis of the vibration information contained in the signal from the vibration detecting unit 1 to be detected, which is identified by the identification unit 402. Note that the position detecting unit 403b performs in advance machine learning of vibration patterns from vibrations detected by the vibration detecting unit 1 when the wheeled platform 12 is moved on the irregular part 5 by a manager (a team leader or the like at the production site).

[0051] As described above, the irregular part 5 is provided on the ground on which the wheeled platform 12 moves, and the position detecting unit 403b detects the position of the wheeled platform 12 on the basis of the pattern of vibration detected by the vibration detecting unit 1 when the wheeled platform 12 moves on the irregular part 5, which enables detection of the position of the wheeled platform 12 and the work state for the wheeled platform 12 or the work object 11 by a single vibration detecting unit 1 without using the transmitter 2, as compared with the first embodiment.

In addition, this improves the maintenance of the position detection system. Specifically, button batteries are used in some sensors such as the vibration detecting unit 1 and the transmitter 2, and these batteries need to be changed in such a case. In particular, the battery of the transmitter 2, which is used as a position beacon, is readily exhausted. In addition, parameter setting is needed for each of the sensors to detect vibration or function as position beacons. Thus, the frequency of battery change and the number of parameter settings are suppressed by using only a single vibration detecting unit 1 without the transmitter 2, which improves the maintenance.

[0052] Fourth Embodiment.

The case in which the vibration detecting unit 1 is mounted on the wheeled platform 12 is presented in the first and third embodiments, and the case in which the vibration detecting units lb are mounted on the work object 11 is presented in the second embodiment. In contrast, a vibration detecting unit similar to the vibration detecting units 1 and lb may further be mounted on a worker or a tool, to perform progress management at a production site.

[0053] For example, a vibration detecting unit is worn on an arm of a worker, and when there is a shortage of a part in an assembly process, the worker moves the arm in a predetermined manner (such as shaking) so that the vibration detecting unit detects the vibration. The controller 4 then recognizes the shortage of the part from the pattern of the vibration and provide notification of the same to the outside by display, audio, or the like.

Alternatively, for example, a vibration detecting unit is mounted on a driver, and the vibration detecting unit detects vibration of thread fastening with the driver. The controller 4 then calculates the time and the number of turns of the thread fastening with the driver from the pattern (amplitude, period, and the like) of the vibration, and when the thread fastening ends in a time equal to or shorter than a predetermined time or with the number of turns equal to or smaller than a predetermined number of turns, determines the thread fastening as unfastened and provides notification of the same to the outside by display, audio, or the like.

[0054] Finally, an example hardware configuration of the controller 4 in the first to fourth embodiments will be described with reference to FIG 15. While an example hardware configuration of the controller 4 in the first embodiment will be described below, the same is applicable to that in the second to fourth embodiment.

The functions of the identification unit 402, the position detecting unit 403, and the work state detecting unit 404 of the controller 4 are implemented by a processing circuit 51. The processing circuit 51 may be dedicated hardware as illustrated in FIG. 15A, or may be a central processing unit (CPU; also called a central processor, a processing unit, a computing unit, a microprocessor, a microcomputer, a processor, or a digital signal processor (DSP)) 52 that executes programs stored in a memory 53 as illustrated in FIG. 15B.

[0055] In a case where the processing circuit 51 is dedicated hardware, the processing circuit 51 may be a single circuit, a composite circuit, a programmed processor, a parallel-programmed processor, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or a combination thereof, for example. Each of the functions of the identification unit 402, the position detecting unit 403, and the work state detecting unit 404 may be implemented by the processing circuit 51, or the functions of the respective units may be collectively implemented by the processing circuit 51.

[0056] In a case where the processing circuit 51 is the CPU 52, the functions of the identification unit 402, the position detecting unit 403, and the work state detecting unit 404 are implemented by software, firmware, or combination of software and firmware. The software and firmware are described in the form of programs and stored in the memory 53. The processing circuit 51 implements the functions of the respective units by reading and executing the programs stored in the memory 53. These programs can also be said to cause a computer to execute the procedures and methods of the identification unit 402, the position detecting unit 403, and the work state detecting unit 404. Note that the memory 53 may be a nonvolatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, or an EEPROM, a magnetic disk, a flexible disk, an optical disk, a compact disc, a mini disc, or a DVD, for example. [0057] Alternatively, some of the functions of the identification unit 402, the position detecting unit 403, and the work state detecting unit 404 may be implemented by dedicated hardware, and others may be implemented by software or firmware. For example, the functions of the identification unit 402 can be implemented by the processing circuit 51, which is dedicated hardware, and the functions of the position detecting unit 403 and the work state detecting unit 404 may be implemented by the processing circuit 51 reading and executing programs stored in the memory 53. [0058] As described above, the processing circuit 51 is capable of implementing the above-described functions by hardware, software, firmware, or combination thereof [0059] Note that the embodiments of the present invention can be freely combined, any components in the embodiments can be modified, and any components in the embodiments can be omitted within the scope of the invention.

INDUSTRIAL APPLICABILITY

[0060] A position detection system according to the present invention is capable of detecting work states, and is suitable for use as a position detection system or the like for detecting the position of a movable body on which a work object is placed, and a work state carried out on the movable body or on the work object placed on the movable body.

REFERENCE SIGNS LIST

[0061] 1: Vibration detecting unit, lb: Vibration detecting unit (second vibration detecting unit), 2: Transmitter, 3: Receiver, 4: Controller, 5: Irregular part, 11: Work object, 12: Movable body, Si: Processing circuit, 52: CPU, 53: Memory, 401. Storage unit, 402: Identification unit, 403, 403b: Position detecting unit, 404: Work state detecting unit, 405: Work position determining unit.

Claims

A position detection system comprising: a vibration detecting unit mounted on a movable body on which a work object is placed, for detecting vibration and transmitting a signal containing vibration information representing the detected vibration and identification information; a transmitter mounted on the movable body, for periodically transmitting a signal containing identification information; a plurality of receivers for receiving signals; an identification unit for identifying a transmission source of a signal received by each receiver on the basis of identification information contained in the signal; a position detecting unit for detecting a position of the transmitter that is the transmission source of the signal received by each receiver on the basis of reception strength of the signal and a result of identification performed by the identification unit; and a work state detecting unit for detecting a work state for the movable body on which the vibration detecting unit that is the transmission source of the signal received by each receiver is mounted or on the work object placed on the movable body on the basis of the vibration information contained in the signal, the result of identification performed by the identification unit, and a result of detection performed by the position detecting unit 2. A position detection system comprising: a vibration detecting unit mounted on a movable body on which a work object is placed, for detecting vibration and transmitting a signal containing vibration information representing the detected vibration and identification information; a sheet-like irregular part arranged on a ground on which the movable body moves a receiver for receiving a signal; an identification unit for identifying a transmission source of a signal received by the receiver on the basis of identification information contained in the signal; a position detecting unit for detecting a position of the vibration detecting unit that is the transmission source of the signal received by the receiver on the basis of vibration information contained in the signal and a result of identification performed by the identification unit; and a work state detecting unit for detecting a work state for the movable body on which the vibration detecting unit that is the transmission source of the signal received by the receiver is mounted or on the work object placed on the movable body on the basis of the vibration information contained in the signal, the result of identification performed by the identification unit, and a result of detection performed by the position detecting unit.
3. The position detection system according to claim 2 wherein the position detecting unit performs in advance machine learning of vibration patterns on the basis of vibration detected by the vibration detecting unit when the movable body moves on the irregular part.
4. The position detection system according to any one of claims 1 to 3, further comprising: a plurality of second vibration detecting units mounted on the work object, for detecting vibration and transmitting a signal containing vibration information representing the detected vibration and identification information; and a work position determining unit for determining whether or not a work position for the work object on which a second vibration detecting unit that is a source of transmission of a signal received by the receiver is mounted is correct on the basis of vibration information contained in the signal, a result of identification performed by the identification unit, and a result of detection performed by the position detecting unit.The position detection system according to claim 4, wherein the work position determining unit performs in advance machine learning of vibration patterns from vibrations detected by the second vibration detecting unit when work is carried out at a correct work position and when the work is carried out at an incorrect work position.