JP6824830B2 - Fall prevention device and work machine - Google Patents

Description

The present invention relates to a fall prevention device and a work machine for preventing a work machine provided with one or more movable parts from toppling over.

Conventionally, in work machines such as power excavators and cranes, measures have been taken to prevent the vehicle body from tipping over. For example, the following patent documents are known.

In Patent Document 1, in order to inform the driver of the dismantling work machine of the stability of the dismantling work machine during operation, the center of gravity of the entire dismantling work machine is calculated based on the angle signals of the boom and the arm, and the calculated center of gravity and dismantling are performed. The respective distances between the front stable fulcrum and the rear stable fulcrum of the work machine are calculated, and the bearing capacity of each of the front stable fulcrum and the rear stable fulcrum is calculated based on the calculated distance and the calculated center of gravity, and the calculated bearing capacity is calculated. Disclose the technology to display on the display.

Patent Document 2 gives a fall warning when the ZMP of the work machine is included in the fall warning area formed outside the safety area formed inside the support polygon of the work machine and inside the support polygon. Disclose the technology for reporting. In this work machine, when it is detected that the work machine is working on a slope from the input information by the operator, the tilt angle of the upper swing body, and the detection information of the posture sensor, the valley side has a higher risk of falling than the mountain side. The width of the fall warning area is set wide.

Japanese Patent No. 2871105 Japanese Patent No. 541516

By the way, in actual cases of falling accidents of work machines, there are many reports of accidents in which the scaffolding of the work machine collapses due to the load of the work machine applied to the end of the slope (the uppermost end of the slope) and the work machine falls. ing. According to an accident case survey recorded in the Construction Industry Safety and Health Yearbook for the past five years, it is reported that about 20% of fall accidents are caused by the collapse of scaffolding.

Therefore, it is important to prevent the work machine from tipping over, taking into consideration the collapse of the ground around the work machine.

However, none of the techniques of Patent Documents 1 and 2 describe the collapse of the scaffolding on the shoulder and the collapse of the scaffolding due to the softness of the ground.

Further, Patent Document 2 discloses that when the work machine is working on a sloping ground, the width of the fall warning area on the valley side is widened, but the topography and hardness of the ground around the work machine are Since it has not been detected, it is not possible to prevent falls in consideration of the collapse of the scaffolding.

The present invention provides a fall prevention device and a work device that prevent the work machine from toppling in consideration of the risk of the ground surrounding the work machine collapsing.

The fall prevention device according to one aspect of the present invention is a fall prevention device for a work machine including at least one movable portion.
A center of gravity calculation unit that calculates the center of gravity of the work machine based on the posture of the movable unit,
An area setting unit for setting a safety area and a warning area surrounding the safety area inside a support polygon determined from a plurality of contact points with the ground of the work machine.
When the center of gravity is located in the caution area, a fall prevention control unit that performs at least one of a warning for notifying the danger of a fall and a fall prevention control that limits the operation of the movable part so that the fall is avoided. When,
Based on the ground information about the ground around the work machine, the area specifying portion for identifying the collapse risk area where there is a risk of collapse in the surrounding ground is provided.
When the collapse risk area is specified by the area identification unit, the area setting unit is located between at least the center of the support polygon and the collapse risk area among the boundary lines between the safety area and the caution area. The boundary line interposed in the support polygon is moved toward the center of the supporting polygon.

According to this aspect, a collapse risk area where there is a risk of collapse is identified from the ground information about the ground on the ground around the work machine, and when the collapse risk area is specified, the boundary line between the safety area and the caution area is identified. Of these, at least the boundary line between the center of the supporting polygon and the collapse risk area is moved toward the center of the supporting polygon. As a result, the operator's operation through the warning or the fall prevention control limits the movement of the center of gravity of the work machine to the collapse danger area side, limits the load of the work machine on the ground on the collapse danger area side, and works due to the collapse. The machine can be prevented from tipping over.

In the above aspect, the ground information includes terrain information indicating the terrain of the ground around the work machine.
It is preferable that the area specifying portion specifies the collapse risk area based on the topographical information.

According to this aspect, since the collapse danger area is specified based on the topographical information indicating the topography of the ground around the work machine, the work machine working near the cliff or on the shoulder, which is often the case of a fall accident, falls. Can be prevented.

In the above aspect, the ground information includes hard soil information indicating the hardness of the ground around the work machine.
It is preferable that the area specifying section specifies the collapse risk area based on the hard soil information.

According to this aspect, since the collapse risk area is specified based on the hard soil information indicating the hardness of the ground around the work machine, it is possible to prevent the work machine working near the soft ground area from tipping over. .. Furthermore, when the collapse risk area is specified by combining the hard soil information of this aspect with the above topographical information, it is possible to more reliably prevent the work machine working near a cliff where the ground is soft or on the shoulder from falling.

In the above aspect, when the terrain information indicates that there is an inclined surface around the area, the area specifying portion preferably includes the inclined surface in the collapse risk area.

According to this aspect, if there is an inclined surface around the work machine, the inclined surface is included in the collapse risk area, so that it is possible to prevent the work machine working near a cliff or on a shoulder, which is often the case of a fall accident, from falling. ..

In the above aspect, when the hard soil information indicates that there is a ground region having a ground strength lower than the reference value in the vicinity, it is preferable that the region specifying portion includes the region in the collapse risk region.

According to this aspect, if there is an area where the ground strength is lower than the reference value around the work machine, that area is included in the collapse risk area, so that the work machine working near the area where the ground is soft can be prevented from tipping over. ..

In the above aspect, the area setting unit calculates a collapse index value indicating the high possibility of the collapse of the collapse risk area based on the ground information, and moves as the collapse index value increases. It is preferable to increase the amount of movement of the boundary line.

According to this aspect, as the collapse index value indicating the high possibility of collapse of the collapse danger area increases, the movement amount of the boundary line to be moved increases, so that the movement amount may collapse. It can be set to an appropriate value according to the height of.

In the above aspect, the warning area surrounds the safety area and the warning area is issued when the center of gravity is located, and the warning area is surrounded and the fall prevention control is performed when the center of gravity is located. Including the control area
When the collapse danger region is specified by the region identification portion, the region setting unit includes at least the center of the support polygon and the collapse danger region in the first boundary line between the safety region and the warning region. The boundary line interposed between them is moved toward the center of the support polygon, and at least between the center of the support polygon and the collapse risk area of the second boundary line between the warning area and the control area. It is preferable to move the boundary line interposed therein toward the center of the supporting polygon.

According to this aspect, when a collapse risk area is specified, at least the boundary line between the center of the support polygon and the collapse risk area of the first boundary line between the safety area and the warning area is the support polygon. Of the second boundary line between the warning area and the control area, at least the boundary line between the center of the support polygon and the collapse risk area is moved toward the center of the support polygon. To. As a result, the operator's operation through the warning or the fall prevention control limits the movement of the center of gravity of the work machine to the collapse danger area side, limits the load of the work machine on the ground on the collapse danger area side, and works due to the collapse. The machine can be prevented from tipping over.

In the above aspect, the weather information acquisition unit that acquires the weather information related to the surrounding weather, and
Further provided with a risk determination unit that determines whether or not there is a risk of the work machine falling based on the weather information.
When the danger determination unit determines that there is a risk of the fall, the area setting unit preferably moves the boundary line between the safety area and the caution area toward the center of the support polygon. ..

According to this aspect, when the weather information indicates, for example, a strong wind, and there is a risk of the work machine falling due to the strong wind, the boundary line between the safety area and the caution area is the center of the supporting polygon. Since it is moved to, it is possible to prevent the work machine from tipping over.

According to the present invention, it is possible to prevent the work machine from tipping over in consideration of the risk of the ground around the work machine collapsing.

It is an external view of the work machine of this invention. It is a figure for demonstrating the basic structure of the work machine which concerns on this invention. It is a block diagram which shows the structure of the work machine which concerns on Embodiment 1 of this invention. It is a figure which shows an example of the distance image data acquired by the distance measurement sensor measuring the ground. It is a figure which shows an example of the change of a warning line and a control line in Embodiment 1. FIG. It is a flowchart which shows the processing of the work machine which concerns on Embodiment 1. It is a block diagram which shows the structure of the work machine which concerns on Embodiment 2. It is a figure explaining the surface wave exploration method. It is a figure which shows an example of the change of a warning line and a control line in Embodiment 2. It is a figure which shows another example of the change of a warning line and a control line in Embodiment 2. It is a flowchart which shows the processing of the work machine which concerns on Embodiment 2. It is a block diagram which shows the structure of the work machine 1 which concerns on Embodiment 3. It is a block diagram which shows the structure of the work machine 1 which concerns on Embodiment 4. FIG.

(Embodiment 1)
[Working machine]
FIG. 1 is an external view of the work machine 1 according to the present invention. The work machine 1 is composed of a work machine including an upper swing body 3 such as a power shovel and a crane. In FIG. 1, the + x direction indicates the front side of the work machine 1, and the −x direction indicates the rear side of the work machine 1. The front and rear are collectively called the front-rear direction (x direction). The + z direction indicates the upper side of the work machine 1, and the −z direction indicates the lower side of the work machine 1. The upper part and the lower part are collectively called the vertical direction (z direction). The + y direction points to the left when the work machine 1 is viewed from the rear to the front, and the −y direction points to the right when the work machine 1 is viewed from the rear to the front. The right and left sides are collectively called the left-right direction.

The work machine 1 is a work machine including at least one movable portion that rotates about a rotation axis and expands and contracts in the longitudinal direction. It includes a work machine 1, a crawler-type lower traveling body 2, an upper rotating body 3 provided on the lower traveling body 2 so as to be swivel, and a working device 4 attached to the upper swivel body 3.

The work device 4 swings with respect to the boom 41 undulatingly attached to the upper swing body 3, the arm 42 swingably attached to the tip of the boom 41, and the tip of the arm 42. It includes a bucket 43 that is movably attached.

Further, the working device 4 swings the boom cylinder 51 that raises and lowers the boom 41 with respect to the upper swing body 3, the arm cylinder 52 that swings the arm 42 with respect to the boom 41, and the bucket 43 with respect to the arm 42. It is provided with a bucket cylinder 53 to be operated.

In the example of the power excavator shown in FIG. 1, the movable portion is composed of a boom 41, an arm 42, a bucket 43, and an upper swivel body 3 constituting the working device 4. As described above, as the movable portion, the component parts of the work machine 1 that affect the center of gravity of the work machine 1 by changing the posture are adopted. For example, the jib of the hydraulic crane may be a moving part. Further, an attachment other than the bucket 43 may be a movable portion. On the contrary, for example, even if the component has a changing posture, the component (for example, nibbler) of the work machine 1 having an extremely low influence on the center of gravity of the work machine 1 is omitted from the moving portion.

[Basic configuration]
FIG. 2 is a diagram for explaining a basic configuration of the work machine 1 according to the present invention. The work machine 1 sets a warning line B1, a control line B2, and a limit line B3. The limit line B3 is a boundary line obtained by continuously connecting the outermost boundary portion from the center of the work machine 1 on the ground plane of the work machine 1. The region surrounded by the limit line B3 is a supporting polygon. When the center of gravity G of the work machine 1 protrudes outside the limit line B3, the work machine 1 rotates about the limit line B3 on the protruding side, and the vehicle body on the opposite side to the protruding side begins to float and eventually falls. To do. Therefore, it is important to prevent the center of gravity G from protruding outward from the limit line B3 in order to prevent the work machine 1 from tipping over.

A warning line B1 and a control line B2 surrounding the warning line B1 are set inside the limit line B3. Either one of the warning line B1 and the control line B2 may be omitted. The warning line B1 is set in the support polygon at a certain distance d1 from the limit line B3, and the control line B2 is set in the support polygon at a certain distance d2 (<d1) away from the limit line B3. In the example of FIG. 2, since the limit line B3 is a quadrangle, the warning line B1 and the control line B2 are quadrangles similar to the limit line B3 whose center is located at the center of the support polygon. However, this is an example, and if the limit line B3 is a polygon other than a quadrangle such as a triangle, the warning line B1 and the control line B2 each have the same shape as the polygon indicated by the limit line B3.

The rectangular area surrounded by the warning line B1 is the safety area D1. The area between the warning line B1 and the control line B2 is a warning area D2 in which a warning described later is issued when the center of gravity G enters. The region between the control line B2 and the limit line B3 is a control region D3 in which the fall prevention control described later is performed when the center of gravity G enters. The warning area D2 surrounds the safety area D1, and the control area D3 surrounds the warning area D2. The warning area D2 and the control area D3 are examples of warning areas, respectively.

The risk of falling increases as the center of gravity G approaches the limit line B3. Therefore, as the center of gravity G approaches the warning line B1 → the control line B2 → the limit line B3, the possibility of the work machine 1 falling increases.

Therefore, when the center of gravity G is located outside the warning line B1, the work machine 1 issues a warning to notify the operator of the work machine 1 of a voice or an image indicating the danger of falling. Further, when the center of gravity G is located outside the control line B2, the work machine 1 is about to fall, and therefore, the work machine 1 performs fall prevention control for avoiding the fall of the work machine 1. The fall prevention control includes, for example, a control for forcibly stopping the work machine 1 and a control for moving the center of gravity G from the limit line B3 to the inside of the work machine 1 regardless of the operation of the operator.

[Change of boundary line based on terrain information]
However, since the above basic configuration is based on the premise that the ground around this support polygon does not collapse, the vehicle body loses support from the ground as soon as the surrounding ground collapses. The risk of falling increases.

If there is a steep slope nearby that may collapse when the work machine 1 approaches, the risk of falling in the vicinity increases. That is, when the center of gravity G moves to the steep slope side, a part of the ground collapses, and the risk of the work machine 1 falling is increased. One of the important information useful for preventing the work machine 1 from tipping over is topographical information indicating the topography of the ground around the work machine 1, and it is possible to detect that there is a steep slope around the work machine 1 from this topography information.

Therefore, in the first embodiment, for example, a steep slope is specified as a collapse risk area where there is a risk of collapse from the topographical information around the work machine 1, and the positions of the warning line B1 and the control line B2 are based on the specified collapse risk area. The risk of falling is reduced by flexibly changing. Hereinafter, the work machine of the first embodiment will be described in detail.

[Block Diagram]
FIG. 3 is a block diagram showing the configuration of the work machine 1 according to the first embodiment of the present invention. In FIG. 3, the flow of hydraulic oil is shown by a thick line, and the flow of control signals is shown by a thin line.

The work machine 1 includes an actuator 21, a control valve 22, a hydraulic pump 23, an engine 24, a controller 25, an operation unit 26, an angle sensor 27, a distance measurement sensor 28, and a notification unit 29. The fall prevention device according to the present invention includes a controller 25, an operation unit 26, an angle sensor 27, a distance measurement sensor 28, and a notification unit 29.

The actuator 21 is composed of, for example, a boom cylinder 51, an arm cylinder 52, a bucket cylinder 53, and a swivel motor that swivels the upper swivel body 3 shown in FIG. However, this is an example, and a traveling motor for traveling the lower traveling body 2 may be adopted.

The hydraulic pump 23 is connected to the drive shaft 24X of the engine 24 and is driven by the power of the engine 24 to discharge hydraulic oil.

The control valve 22 includes, for example, a hydraulic pilot switching valve interposed between the hydraulic pump 23 and the actuator 21, and an electromagnetic valve for adjusting the pilot pressure input to the hydraulic pilot switching valve. The hydraulic pilot valve opens at an opening degree corresponding to the pilot pressure input to the hydraulic pilot valve, and supplies hydraulic oil from the hydraulic pump 23 to the actuator 21 at a flow rate corresponding to the opening degree. The controller 25 inputs a command signal to the solenoid valve, thereby changing the pilot pressure to control the operating speed of the actuator 21.

The engine 24 is composed of, for example, a diesel engine.

The controller 25 is composed of, for example, a computer including a CPU, RAM, and ROM, and includes a center of gravity calculation unit 251, an area identification unit 252, an area setting unit 253, a fall prevention control unit 254, and a storage unit 255.

The center of gravity calculation unit 251 calculates the ZMP of the work machine 1 based on the rotation angle θ, the angular velocity θ', and the angular acceleration θ ”, and calculates the calculated ZMP as the center of gravity of the work machine 1. However, this is an example. Therefore, a static center of gravity may be adopted as the center of gravity. In this case, the center of gravity calculation unit 251 obtains the center of gravity of each movable portion from the rotation angle θ, and calculates the average value of them to calculate the work machine 1. The static center of gravity of the above can be calculated. The rotation angle θ is a parameter indicating the posture of the movable part, and the angular velocity θ'and the angular acceleration θ'are parameters indicating the movement of the movable part.

In calculating ZMP, the center of gravity calculation unit 251 calculates the angular velocity θ'by first-order differentiating the rotation angle θ detected by the angle sensor 27, and second-order the angular acceleration θ'by differentiating the rotation angle θ. Alternatively, if an angular velocity sensor for detecting the angular velocity of the boom 41, the arm 42, and the bucket 43 is provided, the center of gravity calculation unit 251 can acquire the angular velocity detected by the angular velocity sensor. This is also the case when the angular acceleration sensor is provided.

The area specifying unit 252 identifies a collapse risk area from the distance image data of the terrain around the work machine 1 measured by the distance measuring sensor 28. Here, if the distance image data includes a region indicating a steep slope, the region specifying unit 252 may specify that region as a collapse risk region. Here, the steep slope includes, for example, a slope which is an artificial slope created by cutting or embankment. The slope created by cutting is weak because it cuts out the natural ground that was originally stable. In addition, the slope created by the embankment is not yet sufficiently stable in the early days after the embankment is constructed, and the ground is weak. Therefore, the slope is characterized by often collapsing due to changes in conditions such as heavy rain. A natural slope may be adopted as the steep slope.

FIG. 4 is a diagram showing an example of distance image data acquired by the distance measuring sensor 28 measuring the ground. In the example of FIG. 4, the slope E3 made by cutting is located diagonally rearward to the left of the work machine 1, and the work machine 1 is working on the slope E31 of the slope E3. Since the slope E31 is more likely to collapse than the normal ground, the slope E3 collapses as the center of gravity G of the work machine 1 approaches the slope E3, increasing the risk of the work machine 1 falling.

Further, there is a slope E1 by embankment in front of the work machine 1, and the work machine 1 is working at a place immediately below the slope E1. Since the ground of the slope E1 is weak like the slope E1, if the work machine 1 rides on the slope E1 to perform the work, there is a risk that the slope E1 collapses and the work machine 1 falls.

Therefore, in the present embodiment, under such a situation, the warning line B1 and the control line B2 are moved toward the center of the support polygon to reduce the risk of falling.

Here, the area specifying unit 252 has an inclination angle (for example, 10 degrees, 20 degrees, 30 degrees, 40 degrees, etc.) within a certain range (for example, a range of a radius of 5 m or 10 m) with reference to the work machine 1. ) And above, and if there is a region in the distance image data that indicates a slope with an area of a certain area or more, that region may be detected as a steep slope, that is, a collapse risk region. Here, the area setting unit 253 may detect the steep slope as a collapse danger region only when the work machine 1 is located above the steep slope, or when the work machine 1 is located below the steep slope. However, the steep slope may be detected as a collapse risk area, and even when the steep slope is located within the steep slope, the steep slope may be detected as a collapse risk area.

The reference is returned to FIG. When the area specifying unit 252 identifies that there is a collapse danger area around the work machine 1, the area setting unit 253 has at least many supports among the sides constituting the warning line B1 (an example of the first boundary line). The side intervening between the center of the square and the collapse risk area is moved toward the center of the supporting polygon, and at least the center of the supporting polygon among the sides constituting the control line B2 (an example of the second boundary line). Move the side intervening between the collapse risk area and the collapse risk area toward the center of the supporting polygon.

FIG. 5 is a diagram showing an example of change between the warning line B1 and the control line B2 in the first embodiment. FIG. 5A shows a scene in which the upper swivel body 3 swivels diagonally forward to the left from the front and the center of gravity G moves diagonally forward to the left from (a) to (b).

In FIG. 5, the slope 501 is located on the left side of the work machine 1, and the work machine 1 is working on the slope of the slope 501. Since the ground of the slope 501 is weak, the slope 501 tends to collapse from (a) to (b), and the risk of the work machine 1 falling is high.

Therefore, the area setting unit 253 sets the side HL1 (here, the left side) interposed between the center of the support polygon and the slope 501 among the four sides constituting the warning line B1 from the default position to the center of the support polygon. While moving in the direction, move the side HL2 (here, the left side) between the center of the support polygon and the slope 501 out of the four sides constituting the control line B2 to the center of the support polygon from the default position. Let me.

As a result, the distance d11 between the side HL1 and the support polygon (limit line B3) becomes larger than the default distance d1. Therefore, in the scene shown in FIG. 5, when the timing at which the center of gravity G enters the warning area D2 is the default. It will be faster than that. Therefore, in this scene, the warning to the operator is issued earlier, and the operator can be urged to stop the left turn at an early stage. As a result, the risk of the work machine 1 falling due to the collapse of the slope 501 can be reduced.

Similarly, since the distance d21 between the side HL2 and the limit line B3 is larger than the default distance d2, the timing at which the center of gravity G enters the control region D3 is earlier than in the default case in this scene. As a result, in this scene, the operation timing of the fall prevention control can be advanced, and the risk of the work machine 1 falling due to the collapse of the slope 501 can be reduced.

On the other hand, of the four sides constituting each of the warning line B1 and the control line B2, the three sides not intervening between the center of the supporting polygon and the slope 501 have default distances d1 and d2 from the limit line B3. It is maintained. Therefore, in a scene where the center of gravity G does not move in the direction of the slope 501, it is prevented that a warning is issued frequently and the fall prevention control is excessively activated, and operability is ensured.

In the example of FIG. 5, since the boundary line 501a of the slope 501 is parallel to the side closest to the slope 501 among the four sides forming the limit line B3, the sides HL1 and HL2 are in the center direction of the supporting polygon. Has been moved to. However, this is just an example. For example, if the boundary line of the slope 501 is the boundary line 501b as shown in FIG. 5A, the side of the four sides of the warning line B1 that is interposed between the center of the supporting polygon and the slope 501 is the side HL1. , HF1 and, of the four sides of the control line B2, the sides interposed between the center of the supporting polygon and the slope 501 are the two sides HL2 and HF2. In this case, the area setting unit 253 may move the sides HL1, HF1, HL2, and HF2 toward the center of the supporting polygon. Alternatively, the area setting unit 253 moves the upper left apex of the warning line B1 and the control line B2 toward the center of the support polygon to provide a side parallel to the boundary line 501b, thereby providing the warning line B1. And the control line B2 may be changed.

Here, the area setting unit 253 calculates a collapse index value indicating the high possibility of collapse in the collapse risk area from the distance image data when the collapse risk area is specified by the area identification unit 252, and the calculated collapse. The distance d11 and the distance d21 may be set larger as the index value becomes larger. Here, the collapse index value is calculated from, for example, at least one of the inclination angle of the collapse danger region, the height of the collapse danger region, and the area of the collapse danger region. For example, if the inclination angle of the collapse risk area is parameter Pr1, the height of the collapse risk area is parameter Pr2, and the area of the collapse risk area is parameter Pr3, the collapse index value is the collapse index value = α1, Pr1 + α2, Pr2 + α3, Pr3. It is calculated. Note that α1, α2, and α3 are coefficients for normalizing the parameters Pr1, Pr3, and Pr3.

The reference is returned to FIG. When the center of gravity G calculated by the center of gravity calculation unit 251 is located outside the warning line B1, the fall prevention control unit 254 gives a warning to notify the danger of falling. Further, the fall prevention control unit 254 performs fall prevention control when the center of gravity G is located outside the control line B2.

The operation unit 26 is composed of, for example, an operation lever that accepts an operation of changing the posture of the work device 4, and outputs an operation amount corresponding to the tilt amount of the operation lever to the controller 25.

The angle sensor 27 is, for example, four angle sensors that detect the rotation angle θ1 of the boom 41, the rotation angle θ2 of the arm 42, the rotation angle θ3 of the bucket 43, and the rotation angle θ4 of the upper swing body 3. It is composed. The rotation angle θ1 indicates the amount of undulation of the boom 41 with respect to the upper swivel body 3. The rotation angle θ2 indicates the amount of swing of the arm 42 with respect to the boom 41. The rotation angle θ3 indicates the amount of swing of the bucket 43 with respect to the arm 42. The rotation angle θ4 indicates the amount of rotation of the upper swivel body 3 with respect to the lower traveling body 2. When the rotation angles θ1 to θ4 are generically referred to, they are expressed as the rotation angles θ. The angle sensor 27 is composed of, for example, a resolver or a potentiometer.

The distance measuring sensor 28 is composed of, for example, a depth sensor or a stereo camera, and displays distance image data (an example of topographical information) indicating the topography of the surrounding ground in a time series at a predetermined frame rate (for example, about 5 to 50 fps). get.

As a depth sensor, for example, a TOF (time of flight) method that measures the distance distribution of the surrounding ground by measuring the time required for the irradiated infrared light to be reflected by an object and returned with an infrared camera. Distance measurement sensor can be adopted. A stereo camera is, for example, a distance measuring sensor that measures the distance distribution of the surrounding ground by obtaining the parallax between corresponding points in a plurality of images captured by a plurality of cameras.

See FIG. 4 again. In the present embodiment, the distance measuring sensor 28 includes four distance measuring sensors 281, 282, 283, and 284 provided on the front surface, the rear surface, the left side surface, and the right side surface of the upper swivel body 3, respectively. The ranging sensors 281 to 284 are respectively installed on the upper swivel body 3 so that the optical axis faces the ground. Further, the distance measuring sensors 281, 282, 283, and 284 have fan-shaped measuring ranges A1, A2, A3, and A4, respectively. The measurement ranges A1 to A4 overlap with the adjacent measurement ranges A1 to A4 at their ends. As a result, the distance measuring sensors 281 to 284 can measure the terrain in all directions around the work machine 1 and acquire the distance image data indicating the measured terrain.

In this way, the method of grasping the surrounding terrain using the distance measuring sensor 28 allows the work machine 1 itself to grasp the terrain that changes in real time due to work such as excavation, so that it is possible to prevent oversight of the collapse danger area. It is valid. The method of grasping the surrounding terrain using the distance measuring sensor 28 is an example. For example, the area identification unit 252 may specify a collapse risk area by using a wide area topographical information measured in advance using a drone or the like. In this case, the area specifying unit 252 acquires the position of the work machine 1 by using the GPS sensor attached to the work machine 1, and collates the acquired position with the terrain information over a wide area to surround the work machine 1. The collapse risk area may be detected.

Return to FIG. The storage unit 255 stores in advance the default position information of each of the default warning line B1, the control line B2, and the limit line B3. Here, as the default position information, the coordinates of each of the four vertices of the warning line B1, the control line B2, and the limit line B3 in the local coordinate system with the center of the work machine 1 as the origin can be adopted. Here, since the warning line B1, the control line B2, and the limit line B3 are set on the ground, the coordinates of the four vertices of the warning line B1, the control line B2, and the limit line B3 are local coordinates. In the system, it is set on a plane that represents the ground.

The notification unit 29 is composed of a display device and a speaker, and when the fall prevention control unit 254 determines that the center of gravity G is located in the warning area D2, the notification unit 29 notifies the operator of the danger of falling under the control of the fall prevention control unit 254. To do. Here, the notification unit 29 may output a voice message or an alarm sound for notifying the danger of falling from the speaker, or displays a message or an alarm lamp for notifying the danger of falling on the display device. You may.

Next, a method of calculating ZMP in the center of gravity calculation unit 251 will be briefly described.

<Calculation of ZMP>
The center of gravity calculation unit 251 may calculate ZMP using, for example, the following equations (1) and (2).

In the equations (1) and (2), as shown in FIG. 2, the x-axis and the y-axis are set on the ground in contact with the work machine 1, and the z-axis is set vertically upward with respect to the ground. .. In the formulas (1) and (2), p on the left side represents ZMP. p is composed of only x and y components, and the z component is 0. This is because ZMP is a point on the support polygon set on the ground.

The total mass M is a constant. The gravitational acceleration g (gx, gy, gz) is, for example, an x, y, z component of the gravitational acceleration of the work machine 1, and can be detected by, for example, a gravity sensor that detects the inclination angle of the work machine 1. The total center of gravity position c (cx, cy, cz) is the center of gravity of the entire work machine 1, and is a variable that depends on the rotation angle θ of the work machine 1. The total momentum P and the total angular momentum L are the vector sum of the momentum and the angular momentum of each movable part.

The total momentum P and the total angular momentum L are variables that depend on the rotation angle θ, the angular velocity θ', and the angular acceleration θ'. Therefore, the ZMP can be arranged at the target location by adjusting the total momentum P and the total angular momentum L. ..

As described above, the total center of gravity position c, the total momentum P, and the total angular momentum L of the work machine 1 are required for the calculation of ZMP. These physical quantities are kinematically obtained from the rotation angle θ, the angular velocity θ', and the angular acceleration θ'of the work machine 1. Therefore, the equations (1) and (2) have the rotation angle θ and the angular velocity θ',. And it becomes a function of angular acceleration θ ”.

The angle of rotation θ is a vector having a component according to the degree of freedom. Since the work machine 1 in FIG. 1 has four degrees of freedom, the rotation angle θ is represented by a vector composed of four components of θ1, θ2, θ3, and θ4.

Therefore, if there are n degrees of freedom, the angle of rotation θ is represented by a vector consisting of n components represented by the equation (3).

[flowchart]
FIG. 6 is a flowchart showing the processing of the work machine 1 according to the first embodiment. This flowchart is executed at a predetermined sampling cycle. First, the distance measuring sensor 28 acquires the distance image data of the ground around the work machine 1 as topographical information (S601).

Next, the area specifying unit 252 identifies a collapse risk area around the work machine 1 from the distance image data, and sets the warning line B1 and the control line B2 according to the specific result (S602). Here, if there is no collapse danger area around the work machine 1, the area specifying unit 252 sets the distance between the warning line B1 and the limit line B3 to the default distance d1 and controls the control line, as shown in FIG. The distance between B2 and the limit line B3 is set to the default distance d2. On the other hand, if there is a collapse risk area around the work machine 1, the area identification unit 252 is the distance between the side HL1 and the limit line B3 that are interposed between the center of the support polygon and the collapse risk area, as shown in FIG. Is set to a distance d11 larger than the default distance d1, and the distance between the side HL2 and the limit line B3 intervening between the center of the supporting polygon and the collapse danger region is set to a distance d21 larger than the default distance d2. To do.

Next, the center of gravity calculation unit 251 calculates the center of gravity G of the work machine 1 from the rotation angle θ detected by the angle sensor 27.

Next, the fall prevention control unit 254 issues a warning to the operator if the center of gravity G calculated by the center of gravity calculation unit 251 is located outside the warning line B1 (YES in S604) (S605). On the other hand, if the center of gravity G is not located outside the warning line B1 (NO in S604), the fall prevention control unit 254 returns the process to S601 because the center of gravity G is in the safety region D1.

Next, if the center of gravity G is located outside the control line B2 (YES in S606), the fall prevention control unit 254 performs the fall prevention control. On the other hand, if the center of gravity G is located inside the control line B2 (NO in S606), the process returns to S601. In the flowchart of FIG. 6, if the center of gravity G is located outside the control line B2 (YES in S604 and YES in S606), warning and fall prevention control are performed, but the present invention is limited to this. However, only the fall prevention control may be performed.

As described above, according to the work machine 1 of the first embodiment, when the collapse danger area is specified from the map image data of the ground around the work machine 1, the warning line B1 and the control line B2 are formed on the four sides. Of these, at least the side intervening between the center of the support polygon and the collapse risk area is moved toward the center of the support polygon.

As a result, the movement of the center of gravity G of the work machine to the collapse danger region side is restricted by the operator's operation through the warning or by the fall prevention control. As a result, the load of the work machine 1 on the ground on the collapse danger region side is limited, and the work machine 1 can be prevented from falling due to the collapse.

(Embodiment 2)
In addition to topographical information, there is solid soil information indicating the hardness of the ground as useful information for preventing the work machine 1 from tipping over. In particular, when the work machine 1 approaches or enters a place where the ground is soft, there is a risk that the ground will tilt or collapse, and the risk of the work machine 1 falling in the vicinity of that place will increase. Therefore, in the second embodiment, the collapse risk area is specified by using the hard soil information, and the positions of the warning line B1 and the control line B2 are flexibly changed based on the specified collapse risk area, so that there is a risk of falling. To reduce. In the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

[Block Diagram]
FIG. 7 is a block diagram showing the configuration of the work machine 1 according to the second embodiment. The work machine 1 according to the second embodiment further includes a ground sensor 30 and a GPS sensor 31. The ground sensor 30 measures the ground strength of the ground around the work machine 1 by using, for example, a surface wave exploration method. The GPS sensor 31 detects the current position of the work machine 1 by receiving a signal from a GPS satellite.

FIG. 8 is a diagram illustrating a surface wave exploration method. In the surface wave exploration method, as shown in FIG. 8A, the receivers 82 and 83 receive the surface waves W of various frequencies generated by the oscillator 81, and the speed of the surface waves W is detected. It is a method of estimating the ground strength with.

It is generally said that the softer the ground, the slower the surface wave. Further, when the frequency is high as shown in FIG. 8 (b), the surface wave W is transmitted through a relatively shallow portion of the ground E, and when the frequency is low as shown in FIG. 8 (c), the surface wave W is transmitted to the ground E. It travels through the relatively deep part of. Therefore, by changing the frequency of the surface wave W, the ground strength according to the depth can be estimated. As for the speed of the surface wave W, for example, the receiver 82 and the receiver 83 are installed on the ground E at a known distance L, and the receiver 82 on the oscillator 81 side detects the surface wave W. The time T from then until the receiver 83 detects the surface wave W may be measured, and the distance L may be divided by the time T for calculation. Then, by inputting the calculated velocity of the surface wave W into a predetermined function, for example, the ground strength in the regions near the receivers 82 and 82 may be calculated.

The ground sensor 30 may be composed of only (i) receivers 82 and 83, (ii) may be composed of only the oscillator 81, and (iii) receivers 82 and 83 and the oscillator. It may be composed of both 81 and 81.

In the case of (i), the exciter 81 is installed on the ground E, and the receivers 82 and 83 provided on the work machine 1 receive the surface wave W from the exciter 81, so that the ground sensor 30 is on the surface. The velocity of the wave W may be calculated. Further, in the case of (ii), the receivers 82 and 83 are installed on the ground E, and the surface wave W from the oscillator 81 provided in the work machine 1 is received by the receivers 82 and 83, thereby causing the ground sensor. 30 may calculate the velocity of the surface wave W. Further, in the case of (iii), the surface wave W from the oscillator 81 provided in the work machine 1 is received by the receivers 82 and 83 provided in the work machine 1, so that the ground sensor 30 receives the surface wave W. The speed of is calculated. In the case of (iii), if the receiver 82 is installed at a position separated from the oscillator 81 by a known distance, the oscillator 81 outputs the surface wave W and then the receiver 82 outputs the surface wave W. Since the speed of the surface wave W can be detected by measuring the time until reception, the receiver 83 may be omitted.

In the present embodiment, the area identification unit 252 measures the above-mentioned ground strength at a plurality of positions on the work site using the ground sensors 30 to obtain the distribution of the ground strength at the work site. Then, the area specifying unit 252 may store the obtained distribution of the ground strength in the storage unit 255 in advance as hard soil information.

In addition to the above method, the area specifying unit 252 may acquire solid soil information by using the following method.

For example, the area identification unit 252 may acquire hard soil information and store it in the storage unit 255 in advance by applying the high-density surface exploration method, which has been put into practical use in recent years, to the work site. In the high-density surface exploration method, a human is made to hit the ground on which several tens of receivers are arranged with a hammer or the like to oscillate the ground, and the surface wave W is received by multiple receivers at once. This is a method of estimating the two-dimensional distribution of ground strength.

Alternatively, the area identification unit 252 obtains the distribution of the N value at the work site by carrying out a Swedish sounding test that directly measures the N value, which is the hardness of the ground, at the work site, and stores the storage unit 255 as solid soil information. You may memorize it in advance.

Alternatively, the area identification unit 252 obtains the distribution of ground strength at the work site from a database (national ground information retrieval site: Ministry of Land, Infrastructure, Transport and Tourism, etc.) that aggregates the distribution of ground strength measured by the Swedish sounding test. The acquired distribution of ground strength may be stored in the storage unit 255 in advance as hard soil information.

The reference is returned to FIG. For example, the area specifying unit 252 acquires the current position of the work machine 1 by using the GPS sensor 31, and collates the acquired current position with the hard soil information of the work site stored in the storage unit 255 to perform the work. Identify the collapse risk area around the machine 1.

Here, the area specifying unit 252 may specify, for example, a region in a certain range including a position where the ground strength is lower than the reference value in the hard soil information as a collapse risk region. Then, if the area specifying unit 252 identifies that there is a collapse risk area around the work machine 1, the area setting unit 253 uses the same method as in the first embodiment to form the warning line B1 and the control line B2. Should be set.

FIG. 9 is a diagram showing an example of change between the warning line B1 and the control line B2 in the second embodiment. FIG. 9 shows a scene in which the upper swivel body 3 swivels diagonally backward to the left from the front and the center of gravity G moves diagonally backward to the left from the center from (a) to (b).

In FIG. 9, since the collapse risk region 901 having low ground strength is located behind the work machine 1, the collapse danger region 901 becomes more likely to collapse from (a) to (b), and the work machine 1 The risk of falling increases.

Therefore, the area setting unit 253 defaults the distance between the side HB1 (here, the lower side) and the limit line B3 that are interposed between the collapse danger area 901 and the center of the support polygon among the four sides constituting the warning line B1. The distance d11 is set to be larger than the distance d1, and the side HB1 is moved toward the center of the supporting polygon. Further, the area setting unit 253 defaults the distance between the side HB2 (here, the lower side) interposed between the collapse risk area 901 and the center of the support polygon among the four sides constituting the control line B2 and the limit line B3. The distance d21 is set to be larger than the distance d2, and the side HB2 is moved toward the center of the supporting polygon. As a result, in the scene shown in FIG. 9, the timing of issuing a warning and the timing of operating the fall prevention control can be advanced, and the work machine 1 can be prevented from falling due to the collapse of the collapse danger region 901.

FIG. 10 is a diagram showing another example of the change between the warning line B1 and the control line B2 in the second embodiment. FIG. 10 shows a scene in which the upper swivel body 3 swivels diagonally backward to the left from the front and the center of gravity G moves diagonally backward to the left from the center from (a) to (b).

In FIG. 10, since the collapse danger region 1101 is located in all directions of the work machine 1 in all directions, the center of gravity G moves in which direction, including the movement of the center of gravity G diagonally to the left and rear shown in (b). Even so, the collapse danger region 1101 is likely to collapse, and the risk of the work machine 1 falling is increased.

Therefore, the area setting unit 253 sets the distance between the four sides constituting the warning line B1 and the limit line B3 to a distance d11 larger than the default distance d1, and supports each of the four sides from the default position. Move toward the center of. Further, the area setting unit 253 sets the distance between the four sides constituting the control line B2 and the limit line B3 to a distance d21 larger than the default distance d2, and each of the four sides is a support polygon than the default position. Move toward the center of.

As a result, in a scene in which the center of gravity G moves outward in all directions of the work machine 1, including the scene shown in FIG. 10, the timing of issuing a warning and the timing of operating the fall prevention control are accelerated. It is possible to reduce the risk of the work machine 1 falling due to the collapse of the collapse danger region 1101.

When the area specifying unit 252 identifies that there is a collapse risk area around the work machine 1, the area setting unit 253 has a high possibility of collapse so that the value increases as the ground strength decreases. The collapse index value indicating the above may be calculated, and the distance d11 and the distance d21 may be set larger as the calculated collapse index value becomes larger.

FIG. 11 is a flowchart showing the processing of the work machine 1 according to the second embodiment. In FIG. 11, the same processes as those in FIG. 6 are designated by the same reference numerals. First, the area identification unit 252 acquires the solid soil information from the storage unit 255 (S1101). Next, the area specifying unit 252 identifies whether or not there is a collapse risk area around the work machine 1 by collating the hard soil information with the current position of the work machine 1 obtained from the GPS sensor 31. , The warning line B1 and the control line B2 are set based on the specific result (S1102). The details of the setting of the warning line B1 and the control line B2 are the same as those of S602. Hereinafter, the processes S603 to S607 described with reference to FIG. 6 are performed, and measures are taken to reduce the risk of the work machine 1 falling.

As described above, according to the work machine 1 according to the second embodiment, the collapse risk area is specified from the solid soil information of the ground around the work machine 1, and if there is a collapse risk area, the same as in the first embodiment. The warning line B1 and the control line B2 are moved toward the center of the support polygon. As a result, it is possible to prevent the work machine 1 from tipping over due to collapse.

(Embodiment 3)
The work machine 1 according to the third embodiment is a combination of the first embodiment and the second embodiment. FIG. 12 is a block diagram showing the configuration of the work machine 1 according to the third embodiment.

The work machine 1 includes both a distance measuring sensor 28 and a ground sensor 30. The area identification unit 252 identifies the collapse risk area by using both the distance image data acquired by the distance measuring sensor 28 and the hard soil information created in advance using the ground sensor 30. For example, if the region specifying unit 252 has at least one region of a steep slope region and a region having a ground strength of the reference value or less around the work machine 1, the region may be detected as a collapse risk region.

In this case, the area setting unit 253 includes (i) a region having a steep slope but having a ground strength greater than the reference value, (ii) a region having no steep slope but having a ground strength of less than the reference value, and (iii) a steep slope and having the ground strength as a reference. The collapse index value may be calculated by dividing into three patterns in the area below the value, and the warning line B1 and the control line B2 may be changed.

For example, the area setting unit 253 determines that the case of (iii) has the maximum collapse index value, then the cases of (i) and (ii), or the cases of (ii) and (i) next. The collapse index value may be calculated so that the value increases in the order of. Then, the area setting unit 253 sets the warning line B1 so that the distance d11 between the warning line B1 and the limit line B3 and the distance d21 between the control line B2 and the limit line B3 increase as the collapse index value increases. The control line B2 may be set.

Alternatively, when the area setting unit 253 detects the collapse risk area, the inclination angle of the collapse risk area is set to parameter Pr1, the height of the collapse risk area is set to parameter Pr2, the area of the collapse risk area is set to parameter Pr3, and the ground of the collapse risk area is set. Assuming that the intensity is the parameter Pr4, it may be calculated by the collapse index values = α1, Pr1 + α2, Pr2 + α3, Pr3 + α4, Pr4. Note that α1, α2, α3, and α4 are coefficients for normalizing the parameters Pr1 to Pr4.

As described above, according to the work machine 1 of the third embodiment, since the collapse danger area is specified from the map image data around the work machine 1 and the ground strength, the work is performed on a cliff or a law shoulder where the ground is soft. The overturning of the work machine 1 can be prevented more reliably.

(Embodiment 4)
In the first to third embodiments, the risk of the work machine 1 falling is determined based on at least one of the topographical information and the hard soil information, but the work machine 1 according to the fourth embodiment uses the weather information. Further taking into consideration, the risk of the work machine 1 falling over is determined.

FIG. 13 is a block diagram showing the configuration of the work machine 1 according to the fourth embodiment of the present invention. The work machine 1 further includes a weather information acquisition unit 32 and a danger determination unit 256. The weather information acquisition unit 32 is composed of, for example, an anemometer, and detects the wind speed and the wind direction around the work machine 1.

The danger determination unit 256 determines the risk of the work machine 1 falling from the wind speed and the wind direction detected by the weather information acquisition unit 32.

When the danger determination unit 256 determines that there is a risk of tipping, the area setting unit 253 moves the warning line B1 and the control line B2 toward the center of the support polygon. In this case, the danger determination unit 256 may determine that there is a risk of falling if the wind speed is equal to or higher than the reference value.

When the danger determination unit 256 determines that there is a risk of falling, the area setting unit 253 sets the leeward area around the work machine 1 as the fall danger area, and sets the warning line B1 and the control line B2. Of the four constituent sides, at least the side interposed between the fall danger region and the center of the supporting polygon may be moved to the center side of the work machine 1.

Further, when the danger determination unit 256 determines that there is a risk of falling, the area setting unit 253 determines a fall index value indicating the magnitude of the possibility of fall from the wind speed, and the fall index value becomes large. As a result, the amount of movement between the warning line B1 and the control line B2 may be increased.

Further, when the area setting unit 253 detects both the fall danger area and the collapse danger area, at least both areas and the center of the support polygon among the four sides constituting the warning line B1 and the control line B2, respectively. The sides intervening in and may be moved toward the center of the supporting polygon.

In this case, the area setting unit 253 has a higher degree of risk of falling in the area where the fall risk area and the collapse risk area overlap than in the fall risk area and the collapse risk area where both areas do not overlap. Should be determined. Then, the area setting unit 253 moves the side intervening between the overlapping region and the center of the support polygon among the four sides constituting each of the warning line B1 and the control line B2 toward the center of the support polygon. The amount may be larger than the amount of movement in the non-overlapping region.

As described above, according to the work machine 1 according to the fourth embodiment, it is possible to prevent the work machine 1 from tipping over based on the weather information such as the wind direction.

The weather information acquisition unit 32 may be configured by, for example, a communication device that acquires weather information around the work machine 1 from a weather server that provides weather information on the Internet. In this case, the weather information acquisition unit 32 may acquire the weather information around the work machine 1 from the current position of the work machine 1 acquired from the GPS sensor 31.

(Modification example 1)
The area setting unit 253 may move all the sides of the warning line B1 and the control line B2 toward the center of the support polygon regardless of the position of the collapse danger area with respect to the work machine 1.

(Modification 2)
The fall prevention control unit 254 is the remaining area in the control area D3 when the center of gravity G moves in the direction of the limit line B3 in the area intervening between the collapse risk area and the center of the support polygon in the control area D3. The strength of the fall prevention control may be increased as compared with the case where the center of gravity G moves in the direction of the limit line B3. In this case, the fall prevention control unit 254 may increase the strength of the fall prevention control by, for example, increasing the torque applied to the movable portion in order to return the center of gravity G to the center direction of the work machine 1.

(Modification 3)
In the second embodiment, the area identification unit 252 detects the collapse danger area by referring to the hard soil information created in advance, but the present invention is not limited to this, and the ground strength is measured by the ground sensor 30 in real time. May be measured to identify the collapse risk area. In this case, for example, if the ground sensor 30 is installed on each of the front, rear, left, and right sides of the work machine 1, and the ground strength in at least one of the front, back, left, and right directions of the work machine 1 is equal to or less than the reference value. , It may be determined that there is a collapse danger area in that direction.

(Modification example 4)
The work machine 1 may be jacked up or work on a slope. In this case, the supporting polygon may change from a quadrangle to a shape other than a quadrangle such as a triangle. Therefore, the area setting unit 253 determines which of the plurality of representative points is installed on the ground from the detection values of the plurality of load sensors provided at the plurality of representative points of the lower traveling body, and installs the region setting unit 253. A supporting polygon may be set by connecting the representative points. In this case, the default positions of the warning line B1 and the control line B2 may be set so as to have a shape similar to the support polygon, respectively.

B1 Warning line B2 Control line B3 Limit line D1 Safety area D2 Warning area D3 Control area G Center of gravity 1 Work machine 2 Lower traveling body 3 Upper swivel body 4 Working device 25 Controller 26 Operation unit 27 Angle sensor 28, 281, 228, 283 284 Distance measurement sensor 29 Notification unit 30 Ground sensor 251 Center of gravity calculation unit 252 Area determination unit 253 Area setting unit 254 Fall prevention control unit 255 Storage unit 901,1101 Collapse risk area

Claims (9)

A fall prevention device for a work machine having at least one movable part.
A center of gravity calculation unit that calculates the center of gravity of the work machine based on the posture of the movable unit,
An area setting unit for setting a safety area and a warning area surrounding the safety area inside a support polygon determined from a plurality of contact points with the ground of the work machine.
When the center of gravity is located in the caution area, a fall prevention control unit that performs at least one of a warning for notifying the danger of a fall and a fall prevention control that limits the operation of the movable part so that the fall is avoided. When,
Based on the ground information about the ground around the work machine, the area specifying portion for identifying the collapse risk area where there is a risk of collapse in the surrounding ground is provided.
When the collapse risk area is specified by the area identification unit, the area setting unit is located between at least the center of the support polygon and the collapse risk area among the boundary lines between the safety area and the caution area. A fall prevention device that moves the boundary line interposed in the support polygon toward the center of the support polygon. The ground information includes terrain information indicating the terrain of the ground around the work machine.
The fall prevention device according to claim 1, wherein the area specifying unit identifies the collapse danger area based on the topographical information. The ground information includes hard soil information indicating the hardness of the ground around the work machine.
The fall prevention device according to claim 1 or 2, wherein the area specifying unit identifies the collapse risk area based on the hard soil information. The fall prevention device according to claim 2, wherein when the terrain information indicates that there is an inclined surface around the area, the area specifying portion includes the inclined surface in the collapse danger area. The fall prevention device according to claim 3, wherein when the hard soil information indicates that there is a ground area having a ground strength lower than a reference value in the vicinity thereof, the area specifying portion includes the area in the collapse risk area. .. The area setting unit calculates a collapse index value indicating the high possibility of the collapse of the collapse risk area based on the ground information, and as the collapse index value increases, a boundary line to be moved. The fall prevention device according to any one of claims 1 to 5, which increases the amount of movement of the device. The warning area includes a warning area that surrounds the safety area and gives the warning when the center of gravity is located, and a control area that surrounds the warning area and performs the fall prevention control when the center of gravity is located. Including
When the collapse danger region is specified by the region identification portion, the region setting unit includes at least the center of the support polygon and the collapse danger region in the first boundary line between the safety region and the warning region. An intervening boundary line is moved toward the center of the support polygon, and at least between the center of the support polygon and the collapse risk area of the second boundary line between the warning area and the control area. The fall prevention device according to any one of claims 1 to 6, wherein the boundary line interposed therein is moved toward the center of the supporting polygon. A weather information acquisition unit that acquires weather information related to the surrounding weather, and
Further provided with a risk determination unit that determines whether or not there is a risk of the work machine falling based on the weather information.
Claim 1 that the area setting unit moves the boundary line between the safety area and the warning area toward the center of the supporting polygon when the danger determination unit determines that there is a risk of falling. The fall prevention device according to any one of 7 to 7. The fall prevention device according to any one of claims 1 to 8.
A work machine with at least one moving part.

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