Risk detection system and risk detection method

Abstract

To provide a risk detection system and a risk detection method that reduce risky behavior of a worker who uses a stepladder.SOLUTION: A risk detection system comprises: a first position detecting tag that generates a first positional signal relating to a position of a top plate of a stepladder; a second position detecting tag that generates a second positional signal relating to a position of a head; a head-mounted display device that displays an image superimposed on real space; and a risk detection device capable of communicating with each of the first position detecting tag, the second position detecting tag, and the head-mounted display device. The risk detection device includes: an acquisition unit that acquires the first positional signal transmitted from the first position detecting tag and the second positional signal transmitted from the second position detecting tag; a position generation unit that generates top plate positional information for indicating the position of the top plate based on the first positional signal, and generates head positional information for indicating the position of the head based on the second positional signal; a detection unit that detects a risk based on the top plate positional information and the head positional information; and a notification unit that notifies the head-mounted display device of the result of detection by the detection unit.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a hazard detection system and a hazard detection method. [Background technology]

[0002] 2. Description of the Related Art There are known techniques for reducing the risk of injury to workers at various work sites, such as manufacturing facilities. By reducing the risk, the occurrence of accidents can be reduced.

[0003] For example, leaving tools inside an aircraft undergoing maintenance may cause a serious accident. For this reason, maintenance tools are checked thoroughly after work, and only controlled maintenance tools must be used. There are many tasks in which only controlled tools are used in this way. In recent years, it has become common to attach location detection tags to maintenance tools in order to manage them. Furthermore, it has become common to attach location detection tags or two-dimensional codes such as QR codes (registered trademark) to helmets in order to identify workers.

[0004] In addition, support systems that support the actions of workers to prevent accidents are becoming widespread. Patent Document 1 discloses that an augmented reality application that displays virtual objects superimposed on real space is used to reduce the risk of danger to a user. In this document, the presence of an obstacle that may collide with the user in real space is recognized as a danger, and the user is notified of the presence of the obstacle. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2012-155655 A Summary of the Invention [Problem to be solved by the invention]

[0006] Among various types of accidents, many fall accidents are caused by ladders or stepladders. In particular, workers who use stepladders have difficulty recognizing the danger. However, no technology has been known to date that can grasp the usage status of stepladders during work and notify workers of the danger. For this reason, it is difficult to reduce the dangerous behavior of workers who use stepladders.

[0007] Let us consider a case where a technology such as that of Patent Document 1 is used to reduce dangerous actions of workers who use stepladders. In this case, by using a technology such as that of Patent Document 1, the presence of an obstacle that actually exists can be recognized as a danger, and a worker who uses a stepladder can be notified that he or she may collide with the obstacle. However, even if the technology can be used to avoid collisions with obstacles that exist in real space, it cannot detect and notify potential dangers that humans tend to commit. For this reason, even if conventional technology is used, it is difficult to reduce dangerous actions of workers who use stepladders. [Means for solving the problem]

[0008] In order to solve the above problems, a hazard detection system according to a preferred embodiment of the present disclosure is a hazard detection system for detecting hazards in work using a stepladder, comprising: a first position detection tag attached to a top plate of the stepladder and generating a first position signal related to the position of the top plate of the stepladder; a second position detection tag worn on a worker's head and generating a second position signal related to the position of the head; a head-mounted display device worn on the head and displaying an image superimposed on real space; and a head-mounted display device capable of communicating with each of the first position detection tag, the second position detection tag, and the head-mounted display. and a danger detection device, the danger detection device having an acquisition unit that acquires the first position signal transmitted from the first position detection tag and the second position signal transmitted from the second position detection tag, a position generation unit that generates tabletop position information indicating the position of the tabletop based on the first position signal and generates head position information indicating the position of the head based on the second position signal, a detection unit that detects the danger based on the tabletop position information and the head position information, and an alarm unit that alarms the head-mounted display device of the result of detection by the detection unit.

[0009] In order to solve the above problems, a hazard detection method according to a preferred embodiment of the present disclosure is a hazard detection method for detecting hazards in working on a stepladder, the hazard detection method being executed by a hazard detection device having a processor capable of communicating with each of a first position detection tag attached to a top plate of the stepladder and generating a first position signal related to the position of the top plate of the stepladder, a second position detection tag worn on a worker's head and generating a second position signal related to the position of the head, and a head-mounted display device worn on the head and displaying an image superimposed on real space, the hazard detection device acquiring the first position signal transmitted from the first position detection tag and the second position signal transmitted from the second position detection tag, generating top plate position information indicating the position of the top plate based on the first position signal, and generating head position information indicating the position of the head based on the second position signal, detecting the hazard based on the top plate position information and the head position information, and reporting the result of detection by the detection unit to the head-mounted display device. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a danger detection system according to an embodiment. [Diagram 2] 2 is a block diagram of the first location detection tag of FIG. 1. [Diagram 3] 2 is a block diagram of the second location detection tag of FIG. 1. [Figure 4] FIG. 2 is a block diagram of the head-mounted display device of FIG. [Diagram 5] FIG. 2 is a block diagram of the danger detection device of FIG. 1. [Figure 6] FIG. 13 is a diagram showing an example of safe use of a stepladder. [Figure 7] FIG. 13 shows examples of dangerous use of stepladders. [Figure 8] FIG. 13 shows examples of dangerous use of stepladders. [Figure 9] FIG. 13 shows examples of dangerous use of stepladders. [Figure 10] FIG. 13 shows examples of dangerous use of stepladders. [Figure 11]FIG. 13 is a diagram showing a worker climbing a stepladder. [Figure 12] 2 is a flow diagram showing an example of an operation of the danger detection system of FIG. 1. [Figure 13] FIG. 2 is a diagram showing the state before a worker climbs up the stepladder. [Figure 14] 1 is a flow diagram showing an example of a danger detection method. [Figure 15] 13 is a flow chart showing an example of another danger detection method. [Figure 16] 13 is a flow chart showing an example of another danger detection method. [Figure 17] 13 is a flow chart showing an example of another danger detection method. [Figure 18] FIG. 13 is a schematic diagram of a modified example of a danger detection system. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, preferred embodiments of the present disclosure will be described with reference to the accompanying drawings. Note that the dimensions and scale of each part in the drawings may differ from the actual dimensions, and some parts are shown diagrammatically to facilitate understanding. In addition, the scope of the present disclosure is not limited to these forms unless otherwise specified in the following description to the effect that the present disclosure is limited.

[0012] 1. Overview of the Hazard Detection System 100 FIG. 1 is a schematic diagram of a danger detection system 100 according to an embodiment. The danger detection system 100 shown in FIG. 1 detects danger to a worker W working on a stepladder S. Many fall accidents are caused by the stepladder S. Therefore, by detecting danger in working on the stepladder S, it is possible to prevent harm to the worker W and reduce the number of fall accidents. Furthermore, work using the stepladder S is performed at various work sites, such as manufacturing work sites and manufacturing facilities. Therefore, detecting danger in working on the stepladder S is effective in preventing accidents at many work sites.

[0013] As shown in FIG. 1, the danger detection system 100 includes a first position detection tag 2, a second position detection tag 3, a head-mounted display device 4, and a danger detection device 5.

[0014] The first position detection tag 2 is attached to a top board S0 of a stepladder S. The first position detection tag 2 generates a first position signal related to the position of the top board S0.

[0015] The stepladder S is a stepladder that can also be used as a ladder. The stepladder S includes a first member S8, a second member S9, a fastener S4, a locking portion S5, and a top plate S0. Each of the first member S8 and the second member S9 includes two posts S2 and a plurality of steps S3. A plurality of steps S3 spaced apart from each other are provided between the two posts S2. The plurality of steps S3 are connected to the two posts S2. The fastener S4 is long. One end of the fastener S4 is rotatably attached to the first member S8. The other end of the fastener S4 is configured to be lockable with the locking portion S5. The locking portion S5 is attached to the second member S9. The top plate S0 is connected to one end of the first member S8 and the other end of the second member S9.

[0016] The second position detection tag 3 is attached to the helmet H. The helmet H is worn on the head W0 of the worker W. Therefore, the second position detection tag 3 is worn on the head W0. The second position detection tag 3 generates a second position signal related to the position of the head W0. The helmet H is assigned to each worker W. Information about the worker W, such as his / her height, is recorded in the second position detection tag 3.

[0017] The head-mounted display device 4 is, for example, an augmented reality (AR) glass or a mixed reality (MR) glass. The head-mounted display device 4 is worn on the head W0 of the worker W. A head-mounted display device 4 is assigned to each worker W. The head-mounted display device 4 displays an image by superimposing it on a real space. For example, a work manual, a notice of danger, and the like are displayed as images.

[0018] The danger detection device 5 may be, for example, a mobile information terminal such as a smartphone or a tablet, or a personal computer. The danger detection device 5 can communicate with each of the first position detection tag 2, the second position detection tag 3, and the head-mounted display device 4. These can communicate with each other by short-distance wireless communication or wireless or wired LAN conforming to communication standards such as Wi-Fi (registered trademark), Bluetooth (registered trademark), ZigBee (registered trademark), and UWB (Ultra Wide Band). For example, as shown in FIG. 18, the danger detection device 5 may be a server. In this case, for example, the danger detection device 5, the first position detection tag 2, the second position detection tag 3, and the head-mounted display device 4 may be able to communicate with each other via a communication network 9 such as the Internet. Note that the communication network 9 also includes a case where a plurality of communication devices can communicate with each other. For example, the head-mounted display device 4 may have the function of the danger detection device 5.

[0019] 1-2. Configuration of the danger detection system 100 Fig. 2 is a block diagram of the first location detection tag 2 of Fig. 1. As shown in Fig. 2, the first location detection tag 2 includes a processing device 21, a storage device 22, a communication device 23, a first location signal generating device 25, and a power supply device 26.

[0020] The processing device 21 is a processor that controls the entire first position detection tag 2. The processing device 21 includes, for example, a central processing unit (CPU). The processing device 21 realizes various functions by reading and executing various programs and the like stored in the storage device 22.

[0021] The storage device 22 is a recording medium that can be read and written by the processing device 21. The storage device 22 includes one or more storage circuits, such as a Read Only Memory (ROM) and a Random Access Memory (RAM). Although not shown, the storage device 22 stores information including an identifier for identifying the device itself.

[0022] The communication device 23 includes, for example, an antenna for transmitting and receiving radio waves for connecting to the communication network 9, and a communication circuit connected to the antenna for transmitting and receiving signals.

[0023] The first position signal generator 25 generates a first position signal related to the position of the tabletop S0 to which the first position detection tag 2 is attached. The first position signal generator 25 includes an antenna for transmitting and receiving radio waves related to the detection of the position, and a communication circuit connected to the antenna for transmitting and receiving signals. For example, one or more of ToF (Time of Flight), AoA (Angle of Arrival), and TDoA (Time Defference of Arrival) are used to detect the position in the first position signal generator 25.

[0024] The power supply device 26 supplies power to each device included in the first position detection tag 2. The power supply device 26 includes, for example, a battery and a power supply circuit that supplies power from the battery to each device.

[0025] Fig. 3 is a block diagram of the second location detection tag 3 of Fig. 1. As shown in Fig. 3, the second location detection tag 3 includes a processing device 31, a storage device 32, a communication device 33, a second position generating device 35, and a power supply device 36.

[0026] The processing device 31 is similar to the processing device 21, the memory device 32 is similar to the memory device 22, the communication device 33 is similar to the communication device 23, the second position generating device 35 is similar to the first position signal generating device 25, and the power supply device 36 is similar to the power supply device 26.

[0027] The processing device 31 is a processor that controls the entire second position detection tag 3. The storage device 32 is a recording medium that can be read and written by the processing device 31. The second position generation device 35 generates a second position signal related to the position of the head W0 to which the second position detection tag 3 is attached. The power supply device 36 supplies power to each device of the second position detection tag 3.

[0028] Fig. 4 is a block diagram of the head-mounted display device 4 in Fig. 1. As shown in Fig. 4, the head-mounted display device 4 includes a processing device 41, a storage device 42, a communication device 43, a sensor 45, a power supply device 46, an imaging device 47, a display device 48, and an input device 49.

[0029] The processing unit 41 is similar to the processing unit 21 , the storage unit 42 is similar to the storage unit 22 , the communication unit 43 is similar to the communication unit 23 , and the power supply unit 46 is similar to the power supply unit 26 .

[0030] The processing device 41 is a processor that controls the entire head-mounted display device 4. The power supply device 46 supplies power to each device of the head-mounted display device 4. The storage device 42 is a recording medium that can be read and written by the processing device 41. For example, a work manual is stored in the storage device 42. The input device 49 accepts instructions from the worker W. The input device 49 includes, for example, some or all of a microphone, a switch, and a button. The input device 49 may also be configured as a touch panel.

[0031] The sensor 45 detects, for example, the position or angle of the head W0 of the worker W in an absolute coordinate system C0 described below. The sensor 45 includes, for example, one or more of an acceleration sensor, a gyro sensor, an inclination sensor, and a geomagnetic sensor. The sensor 45 detects the movement of the head W0, including the position and posture of the head W0, in a state in which the head-mounted display device 4 is mounted on the head W0 of the worker W.

[0032] The imaging device 47 is a camera, and captures an image of real space. The imaging device 47 includes, for example, an imaging element such as a CCD (Charge Coupled Device) image sensor and a lens. The display device 48 includes, for example, a display such as a liquid crystal display and various lenses, and allows the user to view the image. The display device 48 also displays various images as virtual images in accordance with the movement of the head W0 detected by the sensor 45.

[0033] By using such a head-mounted display device 4, the worker W can avoid climbing the stepladder S while holding a manual or the like in his / her hands when working using the stepladder S. This leaves both hands free for the worker W. Thus, by using the head-mounted display device 4, the occurrence of accidents when using the stepladder S can be reduced compared to when working while holding a manual or the like in his / her hands. Furthermore, by leaving both hands free, productivity is improved. Therefore, by incorporating work assistance using the head-mounted display device 4, safety and productivity can be improved.

[0034] Fig. 5 is a block diagram of the danger detection device 5 of Fig. 1. As shown in Fig. 5, the danger detection device 5 includes a processing device 51, a storage device 52, a communication device 53, and an input device 56. The processing device 51 is similar to the processing device 21, the storage device 52 is similar to the storage device 22, and the communication device 53 is similar to the communication device 23.

[0035] The input device 56 accepts input from a user. The input device 56 includes, for example, a reader that reads tags on which information about the first position detection tag 2 and the second position detection tag 3 is recorded. The input device 56 also includes, for example, some or all of a keyboard, a mouse, a microphone, a switch, and a button. The input device 56 and the display device 55 may also be configured as a touch panel.

[0036] The storage device 52 stores a control program P1 and various data. The control program P1 is a program for executing a danger detection method. The various data include data related to guidance on how to lock the fasteners S4 of the stepladder S, data related to guidance on an appropriate installation location for the stepladder S, and data related to guidance on how to use the stepladder S. Further, the various data includes an operation manual.

[0037] The processing device 51 reads out and executes the control program P1 from the storage device 52. As a result, the processing device 51 functions as an acquisition unit 511, a position generation unit 512, a detection unit 513, and a notification unit 514.

[0038] The acquisition unit 511 acquires the first position signal transmitted from the first position detection tag 2 and the second position signal transmitted from the second position detection tag 3. The acquisition unit 511 also acquires a captured image from the head-mounted display device 4. Furthermore, the acquisition unit 511 acquires information on the height H1 of the worker W, information on the height H2 of the top board S0 when the stepladder S is installed, and information on the maximum usable height HA2 at which the stepladder S can be used safely.

[0039] The position generating unit 512 generates tabletop position information indicating the position of the tabletop S0 based on the first position signal, and generates head position information indicating the position of the head W0 based on the second position signal.

[0040] The detection unit 513 detects danger and makes various judgments such as whether or not there is a danger. Specifically, for example, the detection unit 513 detects danger based on tabletop position information and head position information. Also, for example, the detection unit 513 judges whether the fastener S4 is locked based on a captured image. Furthermore, the detection unit 513 detects danger based on information related to the height H1 of the worker W, the height H2 of the tabletop S0, and information related to the maximum use height HA2 in addition to the tabletop position information and head position information.

[0041] The notification unit 514 notifies the head mounted display device 4 of the result of the detection by the detection unit 513. The notification unit 514 also causes the head mounted display device 4 to display images showing various types of guidance.

[0042] As described above, the danger detection system 100 detects danger during work on the stepladder S. The danger detection system 100 includes a first position detection tag 2, a second position detection tag 3, a head-mounted display device 4, and a danger detection device 5. The first position detection tag 2 is attached to the top board S0 and generates a first position signal related to the position of the top board S0. The second position detection tag 3 is attached to the head W0 of the worker W and generates a second position signal related to the position of the head. The head-mounted display device 4 is attached to the head W0 and displays an image superimposed on the real space. The danger detection device 5 includes an acquisition unit 511, a position generation unit 512, a detection unit 513, and an alarm unit 514. The acquisition unit 511 acquires the first position signal and the second position signal. The position generation unit 512 generates top board position information indicating the position of the top board S0 based on the first position signal, and generates head position information indicating the position of the head W0 based on the second position signal. The detection unit 513 detects danger based on the tabletop position information and the head position information. The notification unit 514 notifies the head-mounted display device 4 of the result of the detection by the detection unit 513.

[0043] The danger detection system 100 can detect potential dangers that humans are prone to commit. It can then notify the user of the presence of the danger. This can prevent the worker W using the stepladder S from engaging in dangerous behavior. Detecting the positional relationship between the head W0 and the top board S0 is the most effective way to detect dangerous behavior. By using this relationship, potential dangers can be detected easily and accurately.

[0044] The following are some examples of potential dangers that humans tend to encounter.

[0045] 1-3. Examples of danger FIG. 6 is a diagram showing an example of safe use of a stepladder S. In the following, an absolute coordinate system C0 is used as appropriate as a reference. The absolute coordinate system C0 includes an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other. One direction along the X-axis is the X1 direction, and the opposite direction to the X1 direction is the X2 direction. One direction along the Y-axis is the Y1 direction, and the opposite direction to the Y1 direction is the Y2 direction. One direction along the Z-axis is the Z1 direction, and the opposite direction to the Z1 direction is the Z2 direction. The Z-axis is a vertical line, the Z1 direction corresponds to a vertical upward direction, and the Z2 direction corresponds to a vertical downward direction. The XY plane is parallel to a horizontal plane.

[0046] In the following, a first coordinate system C1 with mutually orthogonal X', Y' and Z' axes is appropriately used. The first coordinate system C1 is an orthogonal coordinate system of the first position detection tag 2. Therefore, the first coordinate system C1 is a coordinate system fixed with respect to the top board S0, and is an orthogonal coordinate system with an origin at any point on the top board S0. In the following, one direction along the X' axis is the X1' direction, and the direction opposite to the X1' direction is the X2' direction. One direction along the Y' axis is the Y1' direction, and the direction opposite to the Y1' direction is the Y2' direction. One direction along the Z' axis is the Z1' direction, and the direction opposite to the Z1' direction is the Z2' direction.

[0047] Although not shown, the second position detection tag 3 also has an orthogonal coordinate system. The orthogonal coordinate system is a coordinate system fixed with respect to the head W0 when the worker W wears the helmet H on the head W0, and has the head W0 as its origin.

[0048] In the following, a second coordinate system C2 with mutually orthogonal x-, y-, and z-axes is appropriately used. The second coordinate system C2 is an orthogonal coordinate system possessed by the head-mounted display device 4. The second coordinate system C2 has the head W0 as its origin when the head-mounted display device 4 is mounted on the head W0 of the worker W. In this case, the z-axis is an axis parallel to the vertical line, the x-axis is an axis along the left-right direction of the head W0, and the y-axis is an axis along the front-rear direction of the head W0. For example, based on the detection value indicating the rotation around the x-axis detected by the sensor 45, the movement of the worker W facing vertically upward can be detected.

[0049] In the example shown in Fig. 6, the height H2 of the stepladder S is 240 cm. In this case, the body of the worker W needs to be supported by the third step from the top, including the top board S0, among the multiple steps S3. This allows the stepladder S to be used safely. However, this is just one example.

[0050] The maximum use height HA2 is determined by the height H2 to the top board S0 of the stepladder S. The height H2 is the length of the stepladder S in the vertical direction from the installation location G of the stepladder S, such as the ground, to the top board S0. The maximum use height HA2 is a height at which the stepladder S can be used safely, and is a height at which one can climb onto the stepladder S from the installation location G. In the example of FIG. 6, the maximum use height HA2 is the length in the vertical direction from the installation location G to the third step from the top, including the top board S0. Note that the maximum use height HA2 differs depending on the type of stepladder S.

[0051] The installation location G is preferably a flat surface. In the illustrated example, the Y1 direction faces the wall G0, and the Y1 axis is parallel to the normal to the wall G0.

[0052] 7 to 10 are diagrams showing examples of dangerous use of the stepladder S. As shown in Fig. 7, it is dangerous for a worker W to stand on a step S3 that is higher than the maximum use height HA2. Although not shown, it is also dangerous for a worker W to stand on a top board S0 that is higher than the maximum use height HA2.

[0053] As shown in Fig. 8, it is dangerous to lean out from the stepladder S in the X1 or X2 directions, which are the left and right directions. As shown in Fig. 9, it is dangerous for worker W to work facing upward, such as looking vertically upward, while standing on the stepladder S. In other words, it is dangerous for worker W to work facing in the Z1 direction while standing on the stepladder S.

[0054] As shown in FIG. 10, it is dangerous to work while straddling the stepladder S. Similarly, although not shown, it is dangerous to work while sitting on the top board S0 of the stepladder S while straddling the stepladder S. Working while straddling the stepladder S occurs when the first member S8 and the second member S9 of the stepladder S are both close to the wall G0. As shown in FIG. 6, it is preferable to install the stepladder S so that one of the first member S8 and the second member S9 is closer to the wall G0 than the other.

[0055] The dangerous usage examples of the stepladder S shown in Figs. 7 to 10 do not appear dangerous at first glance, but include potential dangers that humans tend to commit. These usage examples can easily cause a loss of balance, leading to the risk of toppling over or falling. The danger detection system 100 can detect such potential dangers that humans tend to commit. Therefore, the risk of danger to the worker W who uses the stepladder S can be reduced.

[0056] 11 is a diagram showing a state in which a worker W climbs up a stepladder S. In the first coordinate system C, in a locked state, the Y1' direction is the direction from the second member S9 to the first member S8. In the illustrated example, in the first coordinate system C1, the Z1' direction is parallel to the normal direction of the top board S0.

[0057] As shown in FIG. 11, the worker W climbs the stepladder S in the Y1' direction. The direction of the stepladder S can be determined from the moving direction in the absolute coordinate system C0 of the second position detection tag 3 when climbing the stepladder S. Therefore, the first coordinate system C1 is associated with the absolute coordinate system C0. In the example of FIG. 11, the Z axis and the Z' axis are parallel, and the Y' axis rotates at an angle α with respect to the Y axis. In this way, the position and posture of the first coordinate system C1 in the absolute coordinate system C0 are known by determining the direction of the stepladder S from the moving direction in the absolute coordinate system C0 of the second position detection tag 3. According to this method, the direction of the stepladder S can be determined without using a gyro sensor or the like, and the direction can be characterized with a simple configuration. The direction of the stepladder S may be determined by a gyro sensor or the like.

[0058] 1-4. Hazard detection method by the danger detection system 100 FIG. 12 is a flow diagram showing an example of the operation of the danger detection system 100 of FIG.

[0059] 12 is started, the danger detection device 5 sets various initial values. Also, for example, the flow is started when the worker W wears the head-mounted display device 4 on his head W0 and issues an instruction to start work to the danger detection device 5 via the head-mounted display device 4. At this time, the danger detection device 5 performs a connection process to the head-mounted display device 4 via the communication network 9. Also, in the following, an example will be described in which the stepladder S is a stepladder that also serves as a ladder.

[0060] In step S01, the acquisition unit 511 acquires physical information. An example of the physical information is the height H1 of the worker W. For example, the input device 56 of the danger detection device 5 reads the tag of the second position detection tag 3, and the acquisition unit 511 acquires the physical information. In addition, the danger detection device 5 performs a connection process to the second position detection tag 3 via the communication network 9.

[0061] In step S02, the acquisition unit 511 acquires ladder information. Examples of the ladder information include a height H2 to a top board S0 of the stepladder S and a maximum usable height HA2 of the stepladder S. For example, the input device 56 of the danger detection device 5 reads the tag of the first position detection tag 2, and the acquisition unit 511 acquires the ladder information. In addition, the danger detection device 5 performs a connection process to the first position detection tag 2 via the communication network 9.

[0062] In step S03, the notification unit 514 causes the head-mounted display device 4 to notify guidance on the locked state of the fastener S4 of the stepladder S. The acquisition unit 511 acquires data on the guidance from the storage device 52, and the notification unit 514 causes the head-mounted display device 4 to notify the worker W of the guidance by voice or image.

[0063] In step S04, the detection unit 513 judges whether or not the fastener S4 is locked. The state in which the fastener S4 is attached to the locking unit S5 is regarded as the locked state. For example, the head-mounted display device 4 captures an image of the vicinity of the fastener S4. The acquisition unit 511 acquires the captured image. The detection unit 513 analyzes the captured image to judge whether or not the fastener S4 of the stepladder S is locked. If it is locked, the process proceeds to step S05. If it is not locked, the process returns to step S03.

[0064] In step S05, the detection unit 513 judges whether the stepladder S is used as a stepladder. The stepladder S is a stepladder that can also be used as a ladder. Therefore, the stepladder S may be used as a stepladder or as a ladder. The lock state of a stepladder is different from that of a ladder. Therefore, the detection unit 513 analyzes the captured image to judge whether the stepladder S is used as a stepladder or as a ladder. If the stepladder S is used as a stepladder, the process proceeds to step S06. If the stepladder S is not used as a stepladder, i.e., if the stepladder S is used as a ladder, the process proceeds to step S13.

[0065] If the detection unit 513 determines in step S05 that the stepladder S is to be used as a ladder, the notification unit 514 issues a guidance to prepare an assistant to support the ladder in step S13. Specifically, the notification unit 514 causes the head-mounted display device 4 to issue the guidance by voice or image.

[0066] When the notification unit 514 notifies the guidance in step S13, the danger detection device 5 then ends the danger detection. For example, in a work using a ladder, since an assistant is present, two or more people can check each other to prevent dangerous work from being performed. On the other hand, when the stepladder S is used as a stepladder, it is assumed that one person will work. In this case, it is considered that the worker W is more likely to be in danger than when the stepladder S is used as a ladder.

[0067] In step S06, the notification unit 514 notifies guidance regarding the installation location of the stepladder S. The acquisition unit 511 acquires data regarding the guidance from the storage device 52. The notification unit 514 causes the head-mounted display device 4 to notify the guidance by voice or image. For example, the notification unit 514 causes the head-mounted display device 4 to notify, as guidance, that a place with large unevenness such as a step, and a place with danger such as a slippery place are not suitable as an installation location for the stepladder S.

[0068] In step S07, the acquisition unit 511 judges whether or not an instruction to the effect that the guidance has been confirmed has been received from the head-mounted display device 4. When the worker W confirms the guidance regarding the installation location of the stepladder S, the worker W inputs that the guidance has been confirmed via the input device 49 of the head-mounted display device 4. The communication device 43 of the head-mounted display device 4 transmits information indicating that this input has been received to the hazard detection device 5 via the communication network 9. The acquisition unit 511 acquires the information indicating that this input has been received and judges whether or not an instruction to the effect that the guidance has been confirmed has been received. Note that this judgment may be made by the detection unit 513.

[0069] In step S08, the acquisition unit 511 acquires signals relating to the positions of the first position detection tag 2 and the second position detection tag 3 from the first position detection tag 2. That is, the acquisition unit 511 acquires a first position signal and a second position signal. Then, the position generation unit 512 generates tabletop position information indicating the position of the tabletop S0 based on the first position signal. Also, the position generation unit 512 generates head position information indicating the position of the head W0 based on the second position signal.

[0070] When the fastener S4 is locked in step S04 described above, the acquisition unit 511 starts acquiring the first position signal and the second position signal in step S08. By starting to measure the position after confirming the locked state, work on the stepladder S can be started safely. Note that the acquisition of the first position signal and the second position signal may be performed before step S04.

[0071] It should be noted that after step S08, the positioning processes by the first position detection tag 2 and the second position detection tag 3, the acquisition of the first position signal and the second position signal by the acquisition unit 511, and the generation of tabletop position information and head position information by the position generation unit 512 continue as appropriate.

[0072] In step S09, the detection unit 513 determines whether the relationship (Z2-Z1) ≈ (H2-H1) is satisfied. H1 is the height of the worker W, and is acquired by the acquisition unit 511 in step S01. H2 is the position of the tabletop S0, and is acquired by the acquisition unit 511 in step S02. HA2 is the maximum use height, and is acquired by the acquisition unit 511 in step S02. Z1 is the position of the head W0 of the worker W. The position Z1 of the head W0 is acquired by the acquisition unit 511 in step S08. Z2 is the position of the tabletop S0. The position Z2 of the tabletop S0 is acquired by the acquisition unit 511 in step S08.

[0073] In step S09, if the relationship (Z2-Z1) ≈ (H2-H1) is satisfied, the process proceeds to step S100. In step S09, if the relationship (Z2-Z1) ≈ (H2-H1) is not satisfied, the process proceeds to step S10.

[0074] Fig. 13 is a diagram showing the state before the worker W climbs up the stepladder S. The case where the relationship (Z2-Z1) ≒ (H2-H1) is satisfied is the state shown in Fig. 13. This state is the state before the worker W climbs up the stepladder S, and the stepladder S is set up in a suitable setting location G. On the other hand, if the worker W has already started climbing the stepladder S or if the stepladder S is set up on a step or the like, the relationship (Z2-Z1) ≒ (H2-H1) is not satisfied.

[0075] 12, if the relationship (Z2-Z1) ≈ (H2-H1) is not satisfied, in step S10, the notification unit 514 causes the head-mounted display device 4 to provide guidance to check the installation location and posture. Specifically, the notification unit 514 causes the head-mounted display device 4 to provide the guidance by voice or image. For example, the notification unit 514 causes the head-mounted display device 4 to provide guidance to the effect that a location with large unevenness such as a step, or a dangerous location such as a slippery location is not suitable as a location for installing the stepladder S.

[0076] In step S11, the detection unit 513 again determines whether or not the relationship (Z2-Z1) ≈ (H2-H1) is satisfied. If the relationship (Z2-Z1) ≈ (H2-H1) is satisfied, the process proceeds to step S100. If the relationship (Z2-Z1) ≈ (H2-H1) is not satisfied, the process proceeds to step S12.

[0077] In step S11, if the relationship (Z2-Z1) ≈ (H2-H1) is not satisfied, in step S12, the notification unit 514 causes the head mounted display device 4 to notify guidance that there is a functional problem. A functional problem may be caused by software, such as the danger detection device 5 not being able to properly read signals transmitted from the first position detection tag 2, the second position detection tag 3, and the head mounted display device 4. Note that functional problems also include those caused by the hardware of the danger detection device 5. Furthermore, it also includes a case where the worker W does not follow the guidance in step S10.

[0078] When the notification unit 514 causes the head-mounted display device 4 to notify guidance that there is a functional problem in step S12, the danger detection device 5 then ends the danger detection. Note that the danger detection device 5 may provide only a simple arbitrary function without ending the danger detection.

[0079] In step S100, detection of various types of danger is started. Specifically, the flow shown in Fig. 14 to Fig. 17 is started. Note that the detection of dangers shown in Fig. 14 to Fig. 17 may be performed simultaneously or in parallel, or any one of them may be performed.

[0080] As described above, in step S09, when the relationship (Z2-Z1) ≈ (H2-H1) is satisfied, danger detection is started in step S100. Therefore, when the stepladder S is a ladder-cum-stepladder, danger detection can be started depending on whether it is used as a ladder or a stepladder. Therefore, even when the stepladder S is a ladder-cum-stepladder, danger detection according to this embodiment is possible. In addition, the judgment by the detection unit 513 in step S09 avoids the possibility that a functional problem occurs in the subsequent detection of danger and sufficient detection cannot be performed. Therefore, the worker W can perform work using the stepladder S with high accuracy and safety.

[0081] Fig. 14 is a flow diagram showing an example of danger detection. In Fig. 14, the danger detection device 5 detects the danger of a worker W standing on the tabletop S0, which is at a height exceeding the maximum use height HA2 as shown in Fig. 7, and notifies the worker W of the danger.

[0082] In step S14, the detection unit 513 judges whether or not the relationship (Z1-Z2)>(H1+HA2-H2) is satisfied. If the relationship (Z1-Z2)>(H1+HA2-H2) is satisfied, the process proceeds to step S15. If this relationship is satisfied, there is danger. If this relationship is satisfied, the worker W is standing on the step S3 or top board S0, which is at a height exceeding the maximum use height HA2. On the other hand, if the relationship (Z1-Z2)>(H1+HA2-H2) is not satisfied, the process proceeds to step S17.

[0083] In step S14, if the relationship (Z1-Z2)>(H1+HA2-H2) is satisfied, in step S15, the notification unit 514 notifies of a danger. The danger is that the worker W is standing on the step S3 or the top board S0, which is at a height exceeding the maximum use height HA2. The notification unit 514 causes the head-mounted display device 4 to notify of the presence of the danger by sound or image. For example, the head-mounted display device 4 issues an alarm that allows the worker W to immediately detect the danger, or displays an image that allows the worker W to immediately detect the danger.

[0084] In step S16, the notification unit 514 issues guidance to indicate that the user should descend to a height equal to or lower than the maximum use height HA2. The notification unit 514 causes the head-mounted display device 4 to issue the guidance by voice or image. After the notification unit 514 issues the guidance in step S16, the process returns to step S14.

[0085] If the relationship (Z1-Z2)>(H1+HA2-H2) is not satisfied in step S14, the detection unit 513 determines in step S17 whether or not there is a work stop event. If there is no work stop event, the process returns to step S14. If there is a work stop event, the danger detection device 5 ends the danger detection. A work stop event includes when the worker W stops the work and when the work is completed.

[0086] When a work stop event occurs, the danger detection device 5 may stop the danger detection without terminating the danger detection. In this case, when the acquisition unit 511 receives an instruction to resume work from the head-mounted display device 4, it resumes the danger detection according to the content of the instruction. For example, the danger detection device 5 may resume from step S14.

[0087] As described above, the danger detection method, which is the operation of the danger detection system 100, detects danger during work on the stepladder S. The danger detection method acquires a first position signal and a second position signal. Then, tabletop position information indicating the position of the tabletop S0 is generated based on the first position signal, and head position information indicating the position of the head W0 is generated based on the second position signal. Then, danger is detected based on the tabletop position information and the head position information. Then, the result of detection by the detection unit 513 is notified to the head-mounted display device 4.

[0088] According to this danger detection method, it is possible to detect potential dangers that humans tend to make. Then, it is possible to notify the presence of the danger. This makes it possible to suppress dangerous actions of the worker W who uses the stepladder S. In addition, by using the work support using the head-mounted display device 4, it is possible to reduce work-related injuries to the worker W who performs the work.

[0089] Furthermore, in steps S01 and S02, the acquisition unit 511 acquires information on the height H1 of the worker W, information on the height H2 of the top board S0 when the stepladder S is set up, and information on the maximum usable height HA2 at which the stepladder S can be safely used. Then, in step S14, the detection unit 513 detects danger based on the top board position information, head position information, information on the height H1, information on the height of the top board S0, and information on the maximum usable height HA2.

[0090] In this way, danger can be easily detected by using five pieces of information: tabletop position information, head position information, height H1 information, tabletop S0 height information, and maximum usable height HA2 information. Therefore, danger can be easily detected without the need to install many sensors at the work site and without the need for large-scale equipment.

[0091] Specifically, in step S14, the detection unit 513 determines that there is a danger if the relationship (Z1-Z2)>(H1+HA2-H2) is not satisfied. In this way, danger can be detected using a simple formula based on the previously acquired information on height H1, height of the tabletop S0, and maximum usable height HA2, as well as the tabletop position information and head position information acquired during work.

[0092] Fig. 15 is a flow diagram showing another example of danger detection. In Fig. 15, the danger detection device 5 detects a danger that the worker W leans to the left or right of the stepladder S as shown in Fig. 8, and notifies the worker W of the danger.

[0093] In step S20, the detection unit 513 judges whether or not the worker W is climbing the stepladder. If the worker W is climbing, the process proceeds to step S21. If the worker W is not climbing, the process repeats step S20.

[0094] For example, the detection unit 513 judges whether the relationship of (Z2-Z1)≈(H2-H1) is satisfied and whether the head W0 is moving in a predetermined direction based on the second position signal. If the relationship of (Z2-Z1)≈(H2-H1) is not satisfied and the head W0 is moving in the Y1' direction based on the second position signal, it is judged that the stepladder S is climbing. In addition, the position generation unit 512 generates movement information regarding the movement direction of the head W0 based on the second position signal, with the predetermined direction as the movement direction. Specifically, the position generation unit 512 associates the first coordinate system C1 with the absolute coordinate system C0, and specifies the orientation of the stepladder S from the movement direction in the absolute coordinate system C0 of the second position detection tag 3 when climbing the stepladder S. Information regarding the orientation is included in the movement information. In the example of FIG. 11, the movement direction is the Y1' direction.

[0095] In step S21, the detection unit 513 determines whether |X2'-X1'| is greater than a set value. The above X2' corresponds to the X coordinate in the absolute coordinate system C0 of the tabletop S0. The above X1' corresponds to the X coordinate in the absolute coordinate system C0 of the head W0 of the worker W. |X2'-X1'| is the difference in the X axis between the tabletop S0 and the head W0.

[0096] If it is satisfied that |X2'-X1'| is greater than the set value, the process proceeds to step S22. If it is satisfied that |X2'-X1'| is greater than the set value, it is dangerous. If it is satisfied that |X2'-X1'| is greater than the set value, the worker W is leaning to the left or right relative to the stepladder S. On the other hand, if it is not satisfied that |X2'-X1'| is greater than the set value, the process proceeds to step S25. The set value is set, for example, depending on the type of stepladder S.

[0097] In step S21, if |X2'-X1'| is greater than the set value, in step S22, the notification unit 514 notifies of a danger. The danger is that the worker W is leaning to the left or right of the stepladder S. The notification unit 514 notifies the head-mounted display device 4 of the presence of the danger by sound or image.

[0098] In step S23, the notification unit 514 issues guidance, for example, to stop leaning to the left and right of the stepladder S and to reset the stepladder S. The notification unit 514 causes the head-mounted display device 4 to issue the guidance by sound or image. When the worker W leans to the left and right of the stepladder S to work, it is considered that there is a problem with the installation location of the stepladder S relative to the work location. The worker W can simply reset the stepladder S so that he or she does not need to lean over.

[0099] In step S24, the detection unit 513 judges whether the installation location has been reviewed or whether the work has been completed. For example, the detection unit 513 may make the judgment in step S24 by determining again whether the relationship (Z2-Z1) ≒ (H2-H1) is satisfied. That is, it judges whether the worker W has descended from the stepladder S. By descending from the stepladder S, the worker W can review the installation location. Also, descending from the stepladder S indicates that the work has been completed.

[0100] In step S24, if the detection unit 513 determines that the installation location is being reviewed or the work is completed, the danger detection device 5 ends the danger detection work. Note that the danger detection device 5 may stop the danger detection without ending the danger detection. In this case, when the acquisition unit 511 receives an instruction to resume the work from the head-mounted display device 4, it resumes the danger detection according to the content of the instruction. For example, the danger detection device 5 may resume from step S20.

[0101] In step S24, if the detection unit 513 determines that the installation location has not been revised or that the work has not been completed, the process returns to step S21.

[0102] In step S21, if it is not satisfied that |X2'-X1'| is greater than the set value, in step S25, the detection unit 513 judges whether or not there is a work stop event. If there is no work stop event, the process returns to step S21. If there is a work stop event, the danger detection device 5 ends the danger detection.

[0103] Note that, when a work stop event occurs, the danger detection device 5 may stop the danger detection without terminating the danger detection. In this case, when the acquisition unit 511 receives an instruction to resume work from the head-mounted display device 4, it resumes the danger detection according to the content of the instruction. For example, the danger detection device 5 may resume from step S20 according to the content of the instruction.

[0104] According to the danger detection method shown in the flow of FIG. 15, the danger detection device 5 detects danger based on the tabletop position information and head position information, and notifies the head-mounted display device 4 of the result of detection by the detection unit 513.

[0105] This danger detection method can also detect potential dangers that humans tend to commit. It can then notify the user of the presence of the danger. This can reduce the risk of dangerous behavior by the worker W who uses the stepladder S.

[0106] 15, in step S20, the position generating unit 512 generates movement information on the movement direction of the head W0 based on the second position signal. In addition, in step S21, the detecting unit 513 detects danger based on |X2'-X1'|, which is the difference between the position of the tabletop S0 and the position of the head W0 in the X1' direction, which intersects with the Y1' direction, which is the movement direction in the horizontal plane. That is, in step S21, the detecting unit 513 determines whether the worker W is performing a dangerous act of leaning to the left or right with respect to the stepladder S.

[0107] The act of leaning to the left or right is difficult for a worker W concentrating on his or her work to notice, and is an act that poses a potential danger. By detecting such an act, it is possible to alert the worker W who is concentrating on his or her work and does not notice the danger. This makes it possible to reduce dangerous acts by the worker W.

[0108] Fig. 16 is a flow diagram showing another example of danger detection. In Fig. 16, the danger detection device 5 detects the danger that the worker W as shown in Fig. 9 is working vertically upward, and notifies the worker W of the danger.

[0109] In step S20, the detection unit 513 judges whether or not the worker W is climbing the stepladder. If the worker W is climbing, the process proceeds to step S31. If the worker W is not climbing, the process repeats step S20. Note that step S20 may be omitted.

[0110] In step S31, the detection unit 513 determines whether the worker W faces vertically upward for a predetermined period of time or more. Specifically, the acquisition unit 511 acquires a detection value detected by the sensor 45 of the head-mounted display device 4. Based on the detection value, the position generation unit 512 generates information indicating that the worker W faces vertically upward as head movement information indicating the movement of the worker W. Based on the information, the detection unit 513 determines whether the worker W faces vertically upward for a predetermined period of time or more.

[0111] If the worker W faces vertically upward for a predetermined period of time or more, the process proceeds to step S32. If the worker W faces vertically upward for a predetermined period of time or more, it is dangerous. If the worker W faces vertically upward for a predetermined period of time or more, the worker W continues working while facing upward. On the other hand, if the worker W does not face vertically upward for a predetermined period of time or more, the process proceeds to step S35.

[0112] In step S31, if the worker W faces vertically upward for a predetermined period of time or more, in step S32, the notification unit 514 notifies the worker W of a danger. The danger is that the worker W is working while facing upward. The notification unit 514 causes the head-mounted display device 4 to notify the worker W of the presence of the danger by sound or image.

[0113] In step S33, the notification unit 514 notifies, for example, guidance indicating that the worker W should stop working facing upward and should reset the stepladder S. The notification unit 514 causes the head-mounted display device 4 to notify the guidance by voice or image. The worker W may stop facing vertically upward, set up the stepladder S, or change the size of the stepladder S.

[0114] In step S34, the detection unit 513 judges whether the installation location has been reviewed or the work has been completed. For example, the detection unit 513 may perform the judgment in step S34 by re-determining whether the relationship (Z2-Z1)>(H2-H1) is satisfied. That is, it judges whether the worker W has descended from the stepladder S. By descending from the stepladder S, the worker W can review the installation location. Also, descending from the stepladder S indicates that the work has been completed. The detection unit 513 may judge whether the worker W has stopped facing the vertical direction based on the detection value of the sensor 45 of the head-mounted display device 4.

[0115] In step S34, when the detection unit 513 determines that various reviews have been performed or the work has been completed, the danger detection device 5 ends the danger detection work. Note that the danger detection device 5 may stop the danger detection without ending the danger detection. In this case, when the acquisition unit 511 receives an instruction to resume the work from the head-mounted display device 4, it resumes the danger detection according to the content of the instruction. For example, the danger detection device 5 may resume from step S20.

[0116] In step S34, if the detection unit 513 determines that various reviews have not been performed or that the work has not been completed, the process returns to step S31.

[0117] In step S31, if the worker W does not face vertically upward for a predetermined time or more, in step S35, the detection unit 513 determines whether or not there is a work stop event. If there is no work stop event, the process returns to step S31. If there is a work stop event, the danger detection device 5 ends the danger detection.

[0118] Note that, when a work stop event occurs, the danger detection device 5 may stop the danger detection without terminating the danger detection. In this case, when the acquisition unit 511 receives an instruction to resume work from the head-mounted display device 4, it resumes the danger detection according to the content of the instruction. For example, the danger detection device 5 may resume from step S20 according to the content of the instruction.

[0119] According to the danger detection method shown in the flow of FIG. 16, the danger detection device 5 detects danger based on the tabletop position information and head position information, and notifies the head-mounted display device 4 of the result of detection by the detection unit 513.

[0120] This danger detection method can also detect potential dangers that humans tend to commit. It can then notify the user of the presence of the danger. This can reduce the risk of dangerous behavior by the worker W who uses the stepladder S.

[0121] Specifically, in step S31, the acquisition unit 511 acquires a detection value detected by the sensor 45 of the head mounted display device 4. Based on the detection value, the position generation unit 512 generates information indicating that the worker W is facing vertically upward as head movement information indicating the movement of the worker W. Based on the head movement information, the detection unit 513 determines whether the worker W has been facing vertically upward for a predetermined period of time or more.

[0122] The act of looking vertically upward for a predetermined period of time or longer is difficult for a worker W concentrating on his / her work to notice, and is an act that involves potential danger. By detecting such an act, it is possible to alert the worker W who is concentrating on his / her work and does not notice the danger. Therefore, it is possible to reduce dangerous acts by the worker W.

[0123] Fig. 17 is a flow diagram showing another example of danger detection. In Fig. 17, the danger detection device 5 detects the danger of working astride the stepladder S, and notifies the worker W of the danger. The danger occurs when the worker W works with both the first member S8 and the second member S9 of the stepladder S close to the wall G0, as shown in Fig. 10.

[0124] In step S20 of Fig. 17, the detection unit 513 judges whether or not the worker W is climbing the stepladder. If the worker W is climbing, the process proceeds to step S31. If the worker W is not climbing, the process repeats step S20. Note that step S20 may be omitted.

[0125] In step S41, the detection unit 513 judges whether the worker W faces the X1' direction or the X2' direction of the stepladder S for a predetermined time or more. Specifically, the acquisition unit 511 acquires a detection value detected by the sensor 45 of the head-mounted display device 4. The position generation unit 512 generates information indicating that the worker W faces the X1' direction or the X2' direction as head movement information indicating the movement of the worker W based on the movement information generated in step S20 and the detection value. Each of the X1' direction and the X2' direction is a direction intersecting with the Y1' direction, which is a movement direction in a horizontal plane. The detection unit 513 judges whether the worker W faces the X1' direction or the X2' direction for a predetermined time or more based on the information. If the worker W faces the X1' direction or the X2' direction for a predetermined time or more, it is highly likely that the worker W is working while straddling the stepladder S.

[0126] If the worker W faces the X1' or X2' direction of the stepladder S for a predetermined period of time or more, the process proceeds to step S42. It is dangerous if the worker W faces the X1' or X2' direction of the stepladder S for a predetermined period of time or more. If the worker W faces the X1' or X2' direction of the stepladder S for a predetermined period of time or more, the worker W continues working while straddling the stepladder S. On the other hand, if the worker W faces the X1' or X2' direction of the stepladder S for a predetermined period of time or more, the process proceeds to step S45.

[0127] In step S42, if the worker W faces the X1' direction or the X2' direction of the stepladder S for a predetermined period of time or more, the notification unit 514 notifies the worker W of a danger. The danger is that the worker W is working while straddling the stepladder S. The notification unit 514 causes the head-mounted display device 4 to notify the worker W of the presence of the danger by sound or image.

[0128] In step S43, the notification unit 514 notifies, for example, guidance indicating that the worker W should stop working while straddling the stepladder S and to reset the stepladder S. The notification unit 514 causes the head-mounted display device 4 to notify the guidance by sound or image. From a state in which both the first member S8 and the second member S9 of the stepladder S are close to the wall G0, the stepladder S is reset so that either the first member S8 or the second member S9 is closer to the wall G0. This allows the worker W to work without straddling the stepladder S, which is safe.

[0129] In step S44, the detection unit 513 judges whether the installation of the stepladder S has been reviewed or whether the work has been completed. For example, the detection unit 513 may make the judgment in step S44 by determining again whether the relationship (Z2-Z1)>(H2-H1) is satisfied. That is, it judges whether the worker W has descended from the stepladder S. By descending from the stepladder S, the worker W can review the installation of the stepladder S. Also, descending from the stepladder S indicates that the work has been completed.

[0130] In step S44, when the detection unit 513 determines that various reviews have been performed or the work has been completed, the danger detection device 5 ends the danger detection work. Note that the danger detection device 5 may stop the danger detection without ending the danger detection. In this case, when the acquisition unit 511 receives an instruction to resume the work from the head-mounted display device 4, it resumes the danger detection according to the content of the instruction. For example, the danger detection device 5 may resume from step S20.

[0131] In step S44, if the detection unit 513 determines that various reviews have not been performed or that the work has not been completed, the process returns to step S41.

[0132] In step S41, if the worker W does not face the X1' direction of the stepladder S for a predetermined time or more, in step S42, the detection unit 513 determines whether or not there is a work stop event. If there is no work stop event, the process returns to step S41. If there is a work stop event, the danger detection device 5 ends the danger detection.

[0133] Note that, when a work stop event occurs, the danger detection device 5 may stop the danger detection without terminating the danger detection. In this case, when the acquisition unit 511 receives an instruction to resume work from the head-mounted display device 4, it resumes the danger detection according to the content of the instruction. For example, the danger detection device 5 may resume from step S20 according to the content of the instruction.

[0134] 17, danger is detected based on tabletop position information and head position information, and the result of detection by the detection unit 513 is notified to the head-mounted display device 4. In the danger detection method shown in the flow of FIG.

[0135] This danger detection method can also detect potential dangers that humans tend to commit. It can then notify the user of the presence of the danger. This can reduce the risk of dangerous behavior by the worker W who uses the stepladder S.

[0136] Specifically, in step S41, the acquisition unit 511 acquires a detection value detected by the sensor 45 of the head mounted display device 4. Based on the movement information generated in step S20 and the detection value, the position generation unit 512 generates information indicating that the head is facing in the X1' direction as head movement information indicating the movement of the worker W. Based on the information, the detection unit 513 determines whether the worker W has been facing in the X1' direction for a predetermined period of time or more.

[0137] If worker W faces the X1' direction for a predetermined period of time or longer, there is a high possibility that worker W is working astride the stepladder S. The act of worker W working astride the stepladder S may appear to be a safe act at first glance. For this reason, this act is one that worker W is likely to perform, and is an act that involves potential danger. By detecting such an act, it is possible to alert worker W who is unaware of the danger. For this reason, it is possible to reduce dangerous acts by worker W.

[0138] According to the various operations performed by the danger detection system 100 described above, dangerous actions of the worker W who uses the stepladder S can be reduced.

[0139] Although the present disclosure has been described above based on the illustrated embodiments, the present disclosure is not limited thereto. In addition, the configurations of the various parts of the present disclosure can be replaced with any configuration that exhibits the same functions as those of the above-described embodiments, and any configuration can be added. [Explanation of symbols]

[0140] 2...first position detection tag, 3...second position detection tag, 4...head-mounted display device, 5...hazard detection device, 9...communication network, 21...processing device, 22...storage device, 23...communication device, 25...first position signal generating device, 26...power supply device, 31...processing device, 32...storage device, 33...communication device, 35...second position signal generating device, 36...power supply device, 41...processing device, 42...storage device, 43...communication device, 45...sensor, 46...power supply device, 47...imaging device, 49...input device, 51...processing device, 52...storage device, 53...communication device position, 55...display device, 56...input device, 100...hazard detection system, 511...acquisition unit, 512...position generation unit, 513...detection unit, 514...alarm unit, C...first coordinate system, C0...absolute coordinate system, C1...first coordinate system, C2...second coordinate system, G...installation location, G0...wall, H...helmet, H1...height, H2...height, HA2...maximum use height, P1...control program, S...stepladder, S0...top plate, S2...support, S4...fastening bracket, S5...locking unit, S8...first member, S9...second member, W...operator, W0...head, α...angle.

Claims

1. A hazard detection system for detecting hazards in ladder work, comprising: a first position detection tag attached to a top plate of the stepladder and configured to generate a first position signal related to a position of the top plate of the stepladder; a second position detection tag attached to the worker's head and configured to generate a second position signal related to a position of the head; a head-mounted display device that is worn on the head and displays an image superimposed on a real space; a danger detection device capable of communicating with each of the first position detection tag, the second position detection tag, and the head-mounted display device; The danger detection device includes: an acquisition unit that acquires the first position signal transmitted from the first position detection tag and the second position signal transmitted from the second position detection tag; a position generating unit that generates tabletop position information indicating a position of the tabletop based on the first position signal, and generates head position information indicating a position of the head based on the second position signal; a detection unit that detects the danger based on the tabletop position information and the head position information; and a notification unit that notifies the head-mounted display device of a result of the detection by the detection unit. A danger detection system comprising:

2. The acquisition unit acquires information on the height of the worker, information on the height of the top plate when the stepladder is installed, and information on a maximum usable height at which the stepladder can be safely used, The detection unit detects the danger based on the tabletop position information, the head position information, the height information, the tabletop height information, and the maximum use height information. The hazard detection system according to claim 1 .

3. The detection unit determines that there is a danger when the relationship (Z1-Z2)>(H1+HA2-H2) is not satisfied, where Z1 is the position of the head, Z2 is the position of the tabletop, H1 is the height of the tabletop, H2 is the height of the tabletop, and HA2 is the maximum use height. The hazard detection system according to claim 2 .

4. The detection unit starts detecting the danger when the relationship (Z2-Z1) ≒ (H2-H1) is satisfied, where Z1 is the position of the head, Z2 is the position of the tabletop, H1 is the height, and H2 is the height of the tabletop. The hazard detection system according to claim 2 .

5. the position generating unit generates movement information related to a moving direction of the head based on the second position signal; The detection unit detects the danger based on a difference between a position of the tabletop and a position of the head in a direction intersecting the movement direction in a horizontal plane. The hazard detection system according to claim 1 .

6. The head-mounted display device has a sensor that detects the movement of the head of the worker, The acquisition unit acquires a detection value detected by the sensor, the position generation unit generates head movement information indicating a movement of the worker based on the detection value; The detection unit detects the danger based on the head movement information. The hazard detection system according to claim 1 .

7. the position generation unit generates, as the head movement information, information indicating that the worker is facing vertically upward based on the detection value; and The detection unit detects a state in which the worker faces vertically upward for a predetermined period of time based on the head movement information, and determines that the state is dangerous. The hazard detection system according to claim 6.

8. the position generation unit generates movement information regarding a movement direction of the head based on the second position signal, and generates, as the head movement information, information indicating that the head is facing a direction intersecting the movement direction in a horizontal plane based on the movement information and the detection value; the detection unit detects a state in which the head is facing a direction intersecting the movement direction for a predetermined period of time based on the head movement information, and determines that the state is dangerous. The hazard detection system according to claim 6.

9. The head-mounted display device has an imaging device that images the real space, The detection unit analyzes the image captured by the imaging device to determine whether a fastener of the stepladder is locked or not, the acquisition unit starts acquiring the first position signal and the second position signal when the fastener is locked. The hazard detection system according to claim 1 .

10. A hazard detection method for detecting hazards in ladder work, comprising: The danger detection device is executed by a processor capable of communicating with each of a first position detection tag attached to a top plate of the stepladder and generating a first position signal related to the position of the top plate of the stepladder, a second position detection tag attached to a head of a worker and generating a second position signal related to the position of the head, and a head-mounted display device attached to the head and displaying an image superimposed on real space, acquiring the first location signal transmitted from the first location detection tag and the second location signal transmitted from the second location detection tag; generating tabletop position information indicating a position of the tabletop based on the first position signal, and generating head position information indicating a position of the head based on the second position signal; The danger is detected based on the tabletop position information and the head position information. A result of the detection by the detection unit is notified to the head-mounted display device. A danger detection method comprising:

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