Obstacle detection device

Abstract

To provide an obstacle detection device capable of easily carrying out high-place work and detecting obstacles within a range wider than that in the prior art.SOLUTION: The obstacle detection device for detecting an obstacle in an upper part of a lifting bucket of a high-place work vehicle which is currently lifted comprises laser ranging means, coordinate calculation means, output control means, and output means. The laser ranging means is for measuring a distance to an object to be measured by radially applying a laser within a roughly vertical plane. The output control means causes the output means to output an approach warning when horizontal isolation is within a predefined horizontal range and vertical isolation is within a predefined approach vertical range.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a technology for ensuring the safety of personnel working in an elevating bucket of an aerial work platform or a bridge inspection vehicle, and more specifically, relates to an obstacle detection device capable of protecting workers from unexpected obstacles when the elevating bucket ascends.

Background Art

[0002] The Industrial Safety and Health Act defines work performed at a height of 2 meters or more above the ground as "aerial work", and stipulates that safety measures for workers including fall prevention shall be implemented when performing this aerial work. Aerial work is frequently carried out at construction sites; for example, aerial work is unavoidable in work near the crown during construction of bridge main girders or tunnel excavation, and in the construction of high-rise buildings, aerial work is carried out at all locations throughout the construction period. In addition, aerial work is not limited to the construction of structures, but is also implemented in various situations such as inspection and repair work of in-service structures, installation of electric wires, and window cleaning of office buildings.

[0003] Among these, for aerial work and bridge inspection (hereinafter referred to as "aerial work, etc.") that are performed at relatively high positions, temporary scaffolds may be installed. If a scaffold is installed, aerial work, etc. can be performed at any time, and the work can be carried out safely. On the other hand, assembling a scaffold requires considerable labor and time, and similar labor and time are required when dismantling the scaffold. Considering factors such as the depreciation of scaffold materials, a corresponding budget must be secured. Therefore, scaffolds tend to be adopted when aerial work, etc. is performed continuously for a certain period of time.

[0004] On the other hand, in cases where work at height is performed temporarily or for a very short period, aerial work platforms are often used, and in cases where bridge inspections are carried out, bridge inspection vehicles are often used. Aerial work platforms and bridge inspection vehicles (hereinafter referred to as "aerial work platforms, etc.") are construction machines that push workers in a lifting bucket to a high position, and a variety of models are used depending on the work purpose and work environment. Aerial work platforms, etc. are classified differently depending on the focus point. For example, if the focus point is on the power source, they are classified into engine-powered, battery-powered, and bi-energy types, and if the focus point is on the mode of transport, they are classified into truck-type, self-propelled, crawler-type, and tire-type. Furthermore, if the focus point is on the lifting mechanism, they can be classified into scissor-type, which uses a pantograph structure to lift and lower, vertical mast-type, which lifts and lowers along a mast, straight-boom-type, which lifts and lowers by extending and retracting several boom sections, and articulated-boom-type, in addition to extending and retracting, the boom can also bend and rotate.

[0005] Incidentally, when the lifting bucket carrying a worker ascends, there may be unforeseen obstacles (such as structural beams, ducts, or racks) positioned above it. Of course, there is no problem if these obstacles are identified early on, but if the lifting bucket continues to ascend without noticing their presence, the worker may collide with the obstacle or become trapped between the lifting bucket and the obstacle, which could lead to an industrial accident.

[0006] Therefore, various technologies have been proposed to detect obstacles in the surrounding area as the lifting bucket rises. Typical countermeasures include the distance sensor method and the physical sensor method proposed in Patent Document 1. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2006-131370 [Overview of the project] [Problems that the invention aims to solve]

[0008] The physical sensor system disclosed in Patent Document 1 involves attaching a pole-shaped sensor to the side of the lifting bucket and issuing an alert when the sensor comes into contact with an obstacle. On the other hand, conventional distance sensors involve installing an upward-facing distance sensor on the handrail or control panel of the lifting bucket and issuing an alert when the distance measured by the distance sensor exceeds a certain level.

[0009] However, both conventional physical sensor systems and distance sensor systems have their drawbacks. Physical sensor systems have the problem that the installed pole-shaped sensors can be an obstacle to working at heights, and while they can detect obstacles where the pole-shaped sensors are located, they cannot detect obstacles outside of the sensor's range. Similarly, distance sensor systems have the problem that while they can detect obstacles where the distance sensors are located, they cannot detect obstacles outside of the sensor's range. Furthermore, neither physical sensor systems nor distance sensor systems have a function to notify workers if they are trapped between the lifting bucket and an obstacle, which could even lead to delays in rescue and treatment.

[0010] The object of the present invention is to solve the problems of the prior art, namely, to provide an obstacle detection device that can easily perform work at heights and can detect obstacles over a wider range than the prior art. [Means for solving the problem]

[0011] The present invention focuses on the use of a laser ranging means and the detection of obstacles in a planar manner by radially irradiated lasers, and is an invention based on a completely new idea.

[0012] The obstacle detection device of the present invention is a device for detecting obstacles above the lifting bucket of an ascending aerial work platform (such as an aerial work platform or bridge inspection vehicle), and comprises a laser distance measuring means, a coordinate calculation means, an output control means, and an output means. The laser distance measuring means is a means for measuring the distance to a measurement target by irradiating a laser radially into a substantially vertical plane (including a vertical plane), and the coordinate calculation means is a means for calculating the horizontal separation (horizontal distance from the laser distance measuring means to the measurement target) and the vertical separation (vertical distance from the laser distance measuring means to the measurement target) based on the distance to the measurement target and the direction of laser irradiation. The output control means is a means for outputting a proximity warning (information indicating that an obstacle is approaching) according to the calculation result by the coordinate calculation means, and the output means is a means for outputting a proximity warning according to the control of the output control means. The output control means causes the output means to output a proximity warning when the horizontal separation is within a predetermined horizontal range and the vertical separation is within a predetermined vertical approach range. Furthermore, the horizontal range is set by the lower and upper horizontal distances from the laser rangefinder, and the approach vertical range is set by the lower and upper vertical distances from the laser rangefinder.

[0013] The obstacle detection device of the present invention may also be configured such that a laser rangefinder is installed on the handrail of the lifting bucket. In this case, the laser rangefinder irradiates a laser into a substantially vertical plane (including the vertical plane) that includes the handrail. The output control means outputs a danger alarm (information indicating that a worker is trapped between the handrail and an obstacle) when the horizontal distance is within the horizontal range and the vertical distance is within a predetermined danger vertical range, and the output means outputs the danger alarm in accordance with the control of the output control means. The danger vertical range is set by the lower limit vertical distance and the upper limit vertical distance from the laser rangefinder, and the upper limit vertical distance related to the danger vertical range is set to a value smaller than the lower limit vertical distance related to the approaching vertical range.

[0014] The obstacle detection device of the present invention may also be configured to output a danger alarm when a predetermined condition (a condition in which the horizontal distance is within the horizontal range and the vertical distance is within a predetermined dangerous vertical range) persists for a predetermined duration threshold.

[0015] The obstacle detection device of the present invention may also be configured to output a danger alarm when a predetermined situation occurs (a situation in which the horizontal distance is within the horizontal range and the vertical distance is within the dangerous vertical range) before a predetermined elapsed time threshold has elapsed, after an approach warning has been output by the output means.

[0016] The obstacle detection device of the present invention may further include an upward movement determination means. This upward movement determination means determines the upward movement of the lifting bucket based on the results of repeated measurements by a laser distance measuring means, and determines that the lifting bucket is moving upward when the vertical distance decreases with repeated measurements by the laser distance measuring means. In this case, the output control means outputs an approach warning when the upward movement determination means determines that the lifting bucket is moving upward.

[0017] The obstacle detection device of the present invention may also calculate the upward speed of the lifting bucket based on repeated measurements by a laser distance measuring means. In this case, the upward determination means determines that the lifting bucket is rising when the upward speed of the lifting bucket exceeds a predetermined speed threshold.

[0018] The obstacle detection device of the present invention may further include a floor surface state setting means in cases where the floor surface expands due to the sliding of a portion of the floor body of the lifting bucket. This floor surface state setting means is capable of setting either a normal state (the state before the portion of the floor body slides) or an expanded state (the state after the portion of the floor body slides). In this case, when the expanded state is set by the floor surface state setting means, the horizontal range is set based on an upper limit horizontal distance that is set to a value greater than the upper limit horizontal distance for the normal state.

[0019] In the obstacle detection device of the present invention, the laser ranging means may be installed at a position lower than the topmost handrail of the lifting bucket. [Effects of the Invention]

[0020] The obstacle detection device of the present invention has the following effects. (1) Since obstacles are detected in a planar manner by radially emitted lasers, omission in obstacle detection can be reduced compared with the prior art. (2) Unlike pole-shaped sensors and the like in the prior art, a relatively compact laser ranging means is provided, so that operations within the lifting bucket can be performed easily without hindrance. (3) By being provided with the ascent determination means, it is possible to detect only obstacles above the operator's head and issue an alert, that is, to suppress erroneous alert issuance. (4) By adopting a specification that outputs a danger warning in addition to an approach warning, an alert can be issued even if an operator is caught in an emergency, so that rescue and treatment can be performed promptly. [Brief Description of the Drawings]

[0021] [Figure 1] A perspective view schematically showing a situation where laser ranging means attached to the lifting bucket of an aerial work vehicle emits a laser. [Figure 2] A block diagram showing the main configuration of the obstacle detection device of the present invention. [Figure 3] A perspective view schematically showing the laser ranging means. [Figure 4] A model diagram for explaining target object coordinates with the laser ranging means as a reference. [Figure 5] A model diagram for explaining an approach region and a danger region. [Figure 6] A flow diagram showing basic processing when the output control means determines an approach situation. [Figure 7] A flow diagram showing processing in which the output control means determines an approach situation using the ascent determination means. [Figure 8]A flowchart illustrating the basic processing steps used by the output control system to determine a dangerous situation. [Figure 9] A flowchart illustrating the process by which the output control means determines a dangerous situation when an obstacle is continuously detected within a dangerous area. [Figure 10] A flowchart illustrating the process by which the output control means determines a dangerous situation when an obstacle is detected within the dangerous area before the elapsed time threshold has elapsed. [Figure 11] A schematic model diagram showing a terminal device that displays proximity information, danger warnings, measurement results, and object coordinates. [Figure 12] (a) is a schematic side view showing the lifting bucket with a portion of the floor not sliding, and (b) is a schematic side view showing the lifting bucket with a portion of the floor sliding. [Figure 13] A flowchart illustrating the process of outputting proximity warnings and danger warnings using the obstacle detection device of the present invention. [Modes for carrying out the invention]

[0022] An example of the obstacle detection device of the present invention will be explained with reference to the figures.

[0023] 1.Overview The present invention enables the detection of obstacles located above the lifting bucket of an "upward working machine" in advance as the bucket rises. Here, an upward working machine is a construction machine having a lifting bucket that can be raised, such as an aerial work platform or a bridge inspection vehicle. If it is mobile, it can be a track type, wheel type, or crawler type. It can also have a telescopic boom, articulated boom, mixed boom, or vertical lifting type, and can be an engine type, battery type, or bienergy type, and can be any of the various forms and types that have been used conventionally. For convenience, the upward working machine will be explained using the example of an aerial work platform. Figure 1 is a schematic perspective view showing the situation in which a laser rangefinder 101 attached to the lifting bucket BC of an aerial work platform HV (upward working machine) is irradiating with a laser LS. As shown in this figure, the laser ranging means 101 irradiates a laser LS radially upward toward the lifting bucket BC, that is, it forms a measurement range on a substantially vertical plane (including the vertical plane) above the lifting bucket BC, and as a result, it searches for obstacles above the lifting bucket BC in a planar manner. By searching in this planar manner, it is possible to detect all obstacles above the lifting bucket BC while it is rising without fail.

[0024] In the example shown in Figure 1, the laser rangefinder 101 is attached to the second horizontal member from the top of the handrail HD that constitutes the lifting bucket BC, and the laser is shone onto a substantially vertical plane that is the same as (or close to) the substantially vertical plane (including the vertical plane) that includes the handrail HD. In this case, obstacles located above the handrail HD can be detected in advance, thereby preventing a worker (for example, an arm or fingers) on the lifting bucket BC from being caught between the handrail HD and an obstacle. The laser rangefinder 101 can be attached to any position other than the one shown in Figure 1, as long as it can shine a laser above the lifting bucket BC. Furthermore, although the example in Figure 1 shows a scissor-type aerial work platform HV, the present invention can be implemented with various aerial work platforms HV, including vertical lifting type aerial work platforms HV, telescopic boom type aerial work platforms HV, articulated boom type aerial work platforms HV, and mixed boom type aerial work platforms HV.

[0025] 2. Obstacle detection device The obstacle detection device of the present invention will now be described in detail. Figure 2 is a block diagram showing the main components of the obstacle detection device 100 of the present invention. As shown in this figure, the obstacle detection device 100 of the present invention is configured to include a laser distance measuring means 101, a coordinate calculation means 102, an output control means 103, and an output means 104. It can also be configured to include an upward determination means 105, a floor surface state setting means 106, a limited area storage means 107, and a display means which will be described later.

[0026] Of the main components of the obstacle detection device 100, the coordinate calculation means 102, output control means 103, rise determination means 105, and floor surface state setting means 106 can be manufactured as dedicated components, or a general-purpose computer device can be used. This computer device includes a processor such as a CPU, memory such as ROM or RAM, input means such as a mouse or keyboard, and a display, and can be composed of a personal computer (PC), server, tablet PC such as iPad®, or mobile terminal including a smartphone. When using a computer device equipped with a display, that display can also be used as the output means 104.

[0027] Furthermore, the limited-area storage means 107 can utilize the storage device of a general-purpose computer, or it can be built on a database server. When built on a database server, it can be located on a local network (LAN) or it can be a cloud server that stores data via the internet.

[0028] The main elements constituting the obstacle detection device 100 of the present invention will be described in detail below.

[0029] (Laser ranging means) The laser distance measuring means 101 is a distance measuring means that measures distance by receiving the reflected signal of a laser LS irradiated onto the object to be measured, and irradiates while changing the irradiation direction (i.e., while swinging or rotating) within a substantially vertical plane (including the vertical plane). By irradiating with the laser LS while changing the irradiation direction in this way, the laser LS is irradiated radially, that is, a measurement range can be formed in a substantially vertical plane. The irradiation direction of the laser LS (irradiation angle in three-dimensional space) is acquired by the laser distance measuring means 101. When the irradiated laser LS is reflected by the object to be measured, the laser distance measuring means 101 receives the reflected signal and can determine the distance to the object to be measured (hereinafter referred to as "measured distance") from the irradiation time of the laser LS and the reception time.

[0030] Figure 3 is a schematic perspective view of the laser rangefinder 101. The laser rangefinder 101 shown in this figure is housed in a case, and the laser LS is projected through a slit provided at the top of the case. The case also houses an alarm buzzer as an output means 104, as well as a small computer PC comprising a coordinate calculation means 102, an output control means 103, an upward determination means 105, and a floor surface state setting means 106. Therefore, when the case shown in this figure is attached to a lifting bucket BC or the like, the laser rangefinder 101 is installed, along with the output means 104, coordinate calculation means 102, output control means 103, upward determination means 105, and floor surface state setting means 106.

[0031] As previously described, the laser rangefinder 101 can be mounted at any position as long as it can irradiate the laser LS upwards onto the lifting bucket BC. Furthermore, a single laser rangefinder 101 can be mounted on the lifting bucket BC, or two laser rangefinders 101 can be mounted as a set, as shown in Figures 1 and 3, or three or more laser rangefinders 101 can be mounted as a set. When mounting two laser rangefinders 101, it is preferable to mount them on opposing handrails HD, as shown in Figure 1. This creates measurement ranges within two different substantially vertical planes, that is, it allows for planar measurement of the area above each opposing handrail HD.

[0032] (Coordinate calculation means) The coordinate calculation means 102 is a means for calculating the position of the object to be measured, that is, the relative coordinates (hereinafter referred to as "object coordinates") with respect to the laser distance measuring means 101 (especially the irradiation point), from the measurement results (measurement distance and irradiation direction) obtained by the laser distance measuring means 101. As shown in Figure 4, the object coordinates can be defined by the horizontal distance (hereinafter referred to as "horizontal separation DH") from the laser distance measuring means 101 (irradiation point) to the object to be measured OJ, and the vertical distance (hereinafter referred to as "vertical separation DV") from the laser distance measuring means 101 to the object to be measured OJ. This horizontal separation DH is determined as the cosine length of the measurement distance DS (distance from the irradiation point to the object to be measured OJ), and the vertical separation DV is determined as the sine length of the measurement distance DS. The radially irradiated laser LS forms a vertical plane, and therefore the measured object to be measured OJ should be located within that vertical plane. Therefore, the object's coordinates can be defined as two-dimensional coordinates on a vertical plane defined by the laser LS (horizontal separation DH, vertical separation DV).

[0033] (Output control means) The output control means 103 is a means for determining whether the object to be measured OJ is an obstacle to an ascending worker, based on the object coordinates obtained by the coordinate calculation means 102, that is, whether the obstacle is approaching the worker (hereinafter referred to as "approach situation"). If an approach situation is determined, the output control means 103 controls the output means 104 to output information indicating that an obstacle is approaching (hereinafter referred to as "approach warning"). The output control means 103 can also determine whether a worker is trapped between the handrail HD and an obstacle (hereinafter referred to as "danger situation"), and if a danger situation is determined, it can control the output means 104 to output information indicating that a worker is trapped between the handrail HD and an obstacle (hereinafter referred to as "danger warning").

[0034] The output control means 103 determines that an object to be measured OJ (object coordinates) is in the "approach area" as an approaching situation, and determines that an object to be measured OJ (object coordinates) is in the "danger area" as a dangerous situation. Figure 5 is a model diagram illustrating the approach area and the danger area. In this figure, the laser distance measuring means 101 (irradiation point) is set as the origin, and a two-dimensional (vertical plane) coordinate system is set such that the left side is positive in the horizontal axis direction and the top side is positive in the vertical axis direction. As shown in this figure, the approach area is defined by the horizontal range WH and the approach vertical range WV1. The horizontal range WH is defined by the lower horizontal distance HL and the upper horizontal distance HU from the laser distance measuring means 101 (irradiation point), and the approach vertical range WV1 is defined by the approach lower vertical distance VL1 and the approach upper vertical distance VU1 from the laser distance measuring means 101 (irradiation point). Figure 5 shows an example where the lower horizontal distance HL is a negative value, but of course, the lower horizontal distance HL can also be set to a value of 0 or greater.

[0035] One of the danger zones is defined by a horizontal range WH and a danger vertical range WV2. The danger vertical range WV2 is defined by the danger lower vertical distance VL2 and the danger upper vertical distance VU2 from the laser ranging means 101 (irradiation point). It is advisable to pre-set the lower horizontal distance HL and upper horizontal distance HU (i.e., horizontal range WH), the approach lower vertical distance VL1 and approach upper vertical distance VU1 (i.e., approach vertical range WV1), and the danger lower vertical distance VL2 and danger upper vertical distance VU2 (i.e., danger vertical range WV2). However, as shown in Figure 5, the danger upper vertical distance VU2 is set to a smaller value (i.e., a lower position) than the approach lower vertical distance VL1. The pre-set horizontal range WH, approach vertical range WV1, and danger vertical range WV2 are stored in the limiting area storage means 107 (Figure 2).

[0036] The following describes the main steps that the output control means 103 uses to determine the proximity situation, with reference to Figure 6. Figure 6 is a flowchart showing the basic processing when the output control means 103 determines the proximity situation. As shown in this figure, once the coordinate calculation means 102 determines the coordinates of the object (Step 201 in Figure 6), the output control means 103 compares the horizontal distance DH with the horizontal range WH (Step 211 in Figure 6). If the horizontal distance DH is included in the horizontal range WH (Yes in Step 211 in Figure 6), the process proceeds to the next step (Step 212 in Figure 6). If the horizontal distance DH is not included in the horizontal range WH (No in Step 211 in Figure 6), it is determined that there is no obstacle OB above the worker (lifting bucket BC) (normal condition) (Step 214 in Figure 6).

[0037] If it is determined that the horizontal distance DH is included in the horizontal range WH, the output control means 103 compares the vertical distance DV with the approaching vertical range WV1 (Step 212 in Figure 6). If the vertical distance DV is included in the approaching vertical range WV1 (Yes in Step 212 in Figure 6), it is determined to be an approaching situation (Step 213 in Figure 6), and if the vertical distance DV is not included in the approaching vertical range WV1 (No in Step 212 in Figure 6), it is determined to be a normal state (Step 214 in Figure 6). If it is determined to be an approaching situation, the output control means 103 controls the output means 104 to output an approaching warning (Step 215 in Figure 6). The output means 104 can use a buzzer or speaker to output sound, or it can use various devices that output information that can be perceived by a person, such as a rotating light (police light), display board, or vibration device. Furthermore, if an approach situation is detected, the output control means 103 can be configured to not only output an approach warning but also to control the raising of the lifting bucket BC by the aerial work platform HV to stop.

[0038] In the procedure shown in Figure 6, there are cases where the output means 104 outputs a proximity warning even when the lifting bucket BC is descending or stopped, and in such cases, the proximity warning is often a false alarm. Therefore, it is also possible to configure the system so that the output control means 103 determines that the lifting bucket BC is approaching, that is, the output means 104 outputs a proximity warning only when the lifting bucket BC is rising. In this case, the rise determination means 105, which determines whether the lifting bucket BC is rising, is used.

[0039] The laser distance measuring means 101 irradiates with a laser LS at extremely short time intervals, that is, the measured distance DS is repeatedly acquired. When the measured distance DS gradually decreases over time, it is considered that the lifting bucket BC is rising. Therefore, the rise determination means 105 can be configured to acquire the measured distance DS repeatedly measured by the laser distance measuring means 101 and determine that the lifting bucket BC is rising when the measured distance DS is gradually decreasing. The rise determination means 105 can also determine the rising speed of the lifting bucket BC by acquiring the measured distance DS acquired by the laser distance measuring means 101 and the measurement time related to that measured distance DS. The rising speed of the lifting bucket BC when there is an obstacle OB above it is the speed at which the worker on the lifting bucket BC approaches the obstacle OB, or in other words, the speed at which the obstacle OB approaches the worker.

[0040] Figure 7 is a flowchart showing the process by which the output control means 103 determines the approach status using the rise determination means 105. As shown in this figure, in the case where the approach status is determined when the lifting bucket BC is rising, the coordinate calculation means 102 determines the coordinates of the object (Step 201 in Figure 7), and the rise determination means 105 determines the rising speed of the lifting bucket BC (Step 216 in Figure 7). Next, if the horizontal separation DH is included in the horizontal range WH (Yes in Step 211 in Figure 7), and the vertical separation DV is included in the approach vertical range WV1 (Yes in Step 212 in Figure 7), the rise determination means 105 evaluates the status of the repeatedly acquired measured distance DS (Step 217 in Figure 7). Then, if the measured distance DS is gradually decreasing (Yes in Step 217 in Figure 7), the process proceeds to the next step (Step 218 in Figure 7), and if the measured distance DS is not gradually decreasing (No in Step 217 in Figure 7), it is determined to be normal (Step 214 in Figure 7).

[0041] When it is determined that the measured distance DS is gradually decreasing, the upward determination means 105 compares the upward speed of the lifting bucket BC with a predetermined threshold (hereinafter referred to as the "speed threshold") (Step 218 in Figure 7). When the upward speed of the lifting bucket BC exceeds (or becomes equal to) the speed threshold (Yes in Step 218 in Figure 7), it is determined that the lifting bucket BC is rising, and the output control means 103 determines this as an approaching situation (Step 213 in Figure 6). On the other hand, when the upward speed of the lifting bucket BC falls below (or becomes equal to) the speed threshold (No in Step 218 in Figure 7), it is determined that the lifting bucket BC is not rising, and the output control means 103 determines that it is in a normal state (Step 214 in Figure 7). It is also possible to configure the system so that the upward speed of the lifting bucket BC does not compare with the speed threshold, i.e., the system determines that the lifting bucket BC is rising based on the gradually decreasing measured distance DS, and the output control means 103 determines this as an approaching situation (Step 213 in Figure 6). In this case, the process of calculating the upward speed of the lifting bucket BC (Step 216 in Figure 7) and the process of comparing the upward speed of the lifting bucket BC with the speed threshold (Step 218 in Figure 7) can be omitted.

[0042] Next, with reference to Figure 8, the main procedure by which the output control means 103 determines a dangerous situation will be explained. Figure 8 is a flowchart showing the basic processing when the output control means 103 determines a dangerous situation. As shown in this figure, once the coordinate calculation means 102 determines the coordinates of the object (Step 201 in Figure 8), the output control means 103 compares the horizontal separation DH with the horizontal range WH (Step 221 in Figure 8). If the horizontal separation DH is included in the horizontal range WH (Yes in Step 221 in Figure 8), the process proceeds to the next step (Step 222 in Figure 8), and if the horizontal separation DH is not included in the horizontal range WH (No in Step 221 in Figure 8), it is determined that the situation is normal (Step 224 in Figure 8).

[0043] If it is determined that the horizontal distance DH is included in the horizontal range WH, the output control means 103 compares the vertical distance DV with the dangerous vertical range WV2 (Step 222 in Figure 8). If the vertical distance DV is included in the dangerous vertical range WV2 (Yes in Step 222 in Figure 8), it is determined to be a dangerous situation (Step 223 in Figure 8), and if the vertical distance DV is not included in the dangerous vertical range WV2 (No in Step 222 in Figure 8), it is determined to be a normal situation (Step 224 in Figure 8). If it is determined to be a dangerous situation, the output control means 103 controls the output means 104 to output a danger warning (Step 225 in Figure 8). The output means 104 can use a buzzer or speaker to output sound, similar to the proximity warning output, or it can use various devices that output information that can be perceived by a person, such as a rotating light (police light), display board, or vibration device. Furthermore, the output means 104 can output different types of information to distinguish between approach warnings and danger warnings, such as by varying the volume of the buzzers for approach warnings and danger warnings, or by outputting approach warnings with a rotating light and danger warnings with a buzzer. In addition, if a dangerous situation is determined, the output control means 103 can be configured to control the raising of the lifting bucket BC by the aerial work platform HV in addition to outputting a danger warning.

[0044] In the procedure shown in Figure 8, there are cases where the output means 104 outputs a danger alarm even when an obstacle OB in the danger zone is detected for only a very short time, and in such cases the danger alarm is often a false alarm. Therefore, it is also possible to configure the system so that the output control means 103 determines that a situation is dangerous, that is, the output means 104 outputs a danger alarm, only when an obstacle OB in the danger zone is detected continuously for a certain period of time.

[0045] Figure 9 is a flowchart showing the process by which the output control means 103 determines a dangerous situation when an obstacle OB is continuously detected within the dangerous area. As shown in this figure, in the case where continuous detection of an obstacle OB is considered, if the horizontal separation DH is included in the horizontal range WH (Yes in Step 221 of Figure 9), and the vertical separation DV is included in the dangerous vertical range WV2 (Yes in Step 222 of Figure 9), the output control means 103 provisionally determines that a dangerous situation exists. If this provisional dangerous situation continues for a period exceeding a predetermined threshold (hereinafter referred to as the "duration threshold") (or being equal to or greater than the duration threshold) (Yes in Step 226 of Figure 9), the output control means 103 ultimately determines that a dangerous situation exists. On the other hand, if the provisional dangerous situation does not exceed the duration threshold (or is less than or equal to it) (No in Step 226 of Figure 9), the output control means 103 determines that the situation is normal (Step 224 of Figure 9).

[0046] As explained above, the system can be configured to determine a dangerous situation and output a danger warning regardless of the output of the proximity warning, or in other words, independently of the determination of the proximity situation. On the other hand, the dangerous situation in which a worker is trapped between the handrail HD and the obstacle OB often occurs after the obstacle OB in the proximity area is detected. Therefore, the system can also be configured so that the output control means 103 determines it to be a dangerous situation, that is, the output means 104 outputs a danger warning, only when certain conditions are met before a certain period of time (hereinafter referred to as the "elapsed time threshold") has elapsed after the output of the proximity warning.

[0047] Figure 10 is a flowchart showing the process by which the output control means 103 determines a dangerous situation when an obstacle OB in the dangerous area is detected before the elapsed time threshold has elapsed. As shown in this figure, in the case where the elapsed time after the proximity warning is output is considered, if the horizontal separation DH is included in the horizontal range WH (Yes in Step 221 of Figure 10) and the vertical separation DV is included in the dangerous vertical range WV2 (Yes in Step 222 of Figure 10), the output control means 103 tentatively determines that a dangerous situation exists. If this tentative determination of a dangerous situation occurs before the elapsed time threshold after the proximity warning is output has elapsed (Yes in Step 227 of Figure 10), the output control means 103 ultimately determines that a dangerous situation exists. On the other hand, if the tentative determination of a dangerous situation occurs after the elapsed time threshold after the proximity warning is output has elapsed (No in Step 227 of Figure 10), the output control means 103 determines that the situation is normal (Step 224 of Figure 10).

[0048] The obstacle detection device 100 may also be equipped with a terminal device TE that outputs information in a manner different from the output means 104. This terminal device TE is a means of displaying visual information such as proximity information, danger warnings, measurement results obtained by the laser distance measuring means 101, and object coordinates obtained by the coordinate calculation means 102. For example, as shown in Figure 11, a tablet PC can be used as the terminal device TE. Of course, it is not limited to tablet PCs; smartphones, personal computers, or display devices such as monitors and displays can also be used as the terminal device TE. In this case, it is preferable to configure the computer PC, which is composed of the coordinate calculation means 102, output control means 103, upward determination means 105, floor surface state setting means 106, etc., to be able to communicate with the terminal device TE, and to make the information acquired (or calculated) by the computer PC also displayable on the terminal device TE. This makes it possible for workers waiting on the ground to understand the status of the lifting bucket BC through the terminal device TE, and furthermore, the status of the lifting bucket BC can be understood even in locations far from the site, such as the management office or supervisor's office.

[0049] (Floor surface condition setting means) As shown in Figure 12, some aerial work platforms (HV) have a floor surface that expands when a portion of the floor FL of the lifting bucket BC slides (sliding to the left in the figure). Figure 12 is a schematic side view of a lifting bucket BC in which a portion of the floor FL slides, where (a) shows the state in which a portion of the floor FL does not slide (hereinafter referred to as the "normal state") and (b) shows the state in which a portion of the floor FL slides (hereinafter referred to as the "expanded state").

[0050] When using an aerial work platform HV in which a portion of the floor FL slides, it is desirable to change the horizontal range WH between the normal state and the extended state, that is, it is desirable to set the approach area and hazard area as different areas in the normal state and the extended state. In other words, it is good to set the horizontal range WH in the normal state and the horizontal range WH in the extended state as separate areas. More specifically, the lower horizontal distance HL is set to a common value in the normal state and the extended state, but the upper horizontal distance HU is set to a different value in the normal state and the extended state, thereby setting the horizontal range WH in the normal state and the horizontal range WH in the extended state separately. However, the upper horizontal distance HU in the extended state is set to a larger (longer) value than the upper horizontal distance HU in the normal state. The pre-set horizontal range WH in the normal state (upper horizontal distance HU in the normal state) and the horizontal range WH in the extended state (upper horizontal distance HU in the extended state) are stored in the restricted area storage means 107, respectively (Figure 2).

[0051] The floor state setting means 106 is a means for receiving the state of the lifting bucket BC (normal state / extended state) and transmitting that state to the output control means 103. For example, the floor state setting means 106 can be configured to receive the state of the lifting bucket BC through operator operation. In other words, the operator visually checks the state of the lifting bucket BC, determines whether it is in the normal state or the extended state, and inputs the result of that determination to the floor state setting means 106. Alternatively, a sensor that detects when a part of the floor body FL slides can be used. In this case, the floor state setting means 106 can be configured to determine it as the extended state when the sensor detects a signal and to determine it as the normal state when the sensor does not transmit a signal.

[0052] If the obstacle detection device 100 is equipped with a floor surface state setting means 106, the output control means 103 performs the determination process in the following procedure. That is, when the floor surface state setting means 106 indicates that the lifting bucket BC is in the normal state, the output control means 103 reads the horizontal range WH of the normal state from the restricted area storage means 107 and then compares the horizontal distance DH with the horizontal range WH. On the other hand, when the floor surface state setting means 106 indicates that the lifting bucket BC is in the extended state, the output control means 103 reads the horizontal range WH of the extended state from the restricted area storage means 107 and then compares the horizontal distance DH with the horizontal range WH.

[0053] (Example of use) An example of using the obstacle detection device 100 of the present invention will be explained with reference to Figure 13. Figure 13 is a flowchart showing the main processing flow for outputting proximity warnings and danger warnings using the obstacle detection device 100 of the present invention. In this diagram, the center column shows the processing to be performed, the left column shows the information necessary for that processing, and the right column shows the information generated from that processing.

[0054] In order to output proximity warnings or danger warnings, measurement by the laser distance measuring means 101 is first started as shown in Figure 13 (Step 301 in Figure 13). Accordingly, the laser distance measuring means 101 continues to irradiate with the laser LS at very short time intervals, that is, the measured distance DS is repeatedly acquired. Whenever the measured distance DS is acquired, the coordinate calculation means 102 calculates the coordinates of the object (horizontal separation DH, vertical separation DV) (Step 302 in Figure 13).

[0055] Meanwhile, the upward movement determination means 105 determines the upward movement speed of the lifting bucket BC (Step 303 in Figure 13) and determines whether or not the lifting bucket BC is moving upward (Step 304 in Figure 13). Specifically, it is determined that the lifting bucket BC is moving upward when the measured distance DS is gradually decreasing and the upward movement speed of the lifting bucket BC exceeds a speed threshold.

[0056] When the upward movement determination means 105 determines that the lifting bucket BC is rising, the output control means 103 executes a process to determine the proximity status (Step 305 in Figure 13). Specifically, when the object to be measured OJ (object coordinates) is in the proximity area, it is determined to be a proximity status, and when the object to be measured OJ is not in the proximity area, it is determined to be a normal state (a situation where there is no obstacle OB above the lifting bucket BC). Then, when the proximity status is determined by the output control means 103, the output means 104 outputs a proximity warning (Step 306 in Figure 13).

[0057] When the output control means 103 performs a determination process for proximity, the output control means 103 executes a determination process for a dangerous situation (Step 307 in Figure 13). Specifically, it determines that a dangerous situation exists when the object to be measured OJ (object coordinates) is in the dangerous area, and determines that the situation is normal when the object to be measured OJ is not in the dangerous area. Then, when the output control means 103 determines that a dangerous situation exists, the output means 104 outputs a danger alarm (Step 308 in Figure 13). [Industrial applicability]

[0058] The obstacle detection device of the present invention can be suitably used in a variety of high-altitude work, including construction of bridge girders, work near the top of tunnels during excavation, construction of high-rise buildings, inspection and repair work on structures in use, installation of power lines, and window cleaning of office buildings. Considering that the present invention enables safe work at heights, in other words, contributes to reducing industrial accidents, it can be said that this invention has the potential to make a significant contribution not only to industrial use but also to society. [Explanation of Symbols]

[0059] 100 Obstacle detection device of the present invention 101 Laser range measuring means (of the obstacle detection device) 102 Coordinate calculation means (of the obstacle detection device) 103 Output control means (of the obstacle detection device) 104 Output means (of the obstacle detection device) 105 (Obstacle detection device) means for determining upward movement 106 (Floor surface condition setting means of the obstacle detection device) 107 (Obstacle detection device) Limited area storage means BC (aerial work platform) lifting bucket FL (floor of the lifting bucket) Handrail for HD (lifting bucket) HV Aerial Work Platform LS laser Out of bounds (OB) OJ Measurement target PC (computer for obstacle detection device) TE (Terminal equipment for obstacle detection devices)

Claims

1. A device for detecting obstacles above a lifting bucket while it is rising, A laser rangefinder that measures the distance to an object by irradiating a laser radially into a vertical or nearly vertical plane, A coordinate calculation means calculates the horizontal distance (horizontal separation) and the vertical distance (vertical separation) from the laser distance measuring means to the object to be measured, based on the distance to the object to be measured and the direction of laser irradiation. An output control means that outputs an approach warning indicating that the obstacle is approaching, or a danger warning indicating that a worker is trapped between the handrail of the lifting bucket and the obstacle, in accordance with the calculation result by the coordinate calculation means. The system includes an output means that outputs the proximity warning or the danger warning in accordance with the control of the output control means, The laser rangefinder is installed on the handrail and irradiates a laser into a vertical or substantially vertical plane including the handrail. The output control means causes the output means to output the proximity warning when the horizontal distance is within a predetermined horizontal range and the vertical distance is within a predetermined vertical approach range. Furthermore, the output control means causes the output means to output the danger alarm when the situation in which the horizontal distance is within the horizontal range and the vertical distance is within a predetermined dangerous vertical range continues for a predetermined duration threshold, The aforementioned horizontal range is defined by the lower horizontal distance and the upper horizontal distance from the laser range measuring means. The aforementioned approach vertical range is determined by the lower vertical distance and the upper vertical distance from the laser range measuring means. The aforementioned dangerous vertical range is defined by the lower and upper vertical distances from the laser ranging means, and the upper vertical distance related to the dangerous vertical range is set to a value smaller than the lower vertical distance related to the approaching vertical range. An obstacle detection device characterized by the following features.

2. A device for detecting obstacles above a lifting bucket while it is rising, A laser rangefinder that measures the distance to an object by irradiating a laser radially into a vertical or nearly vertical plane, A coordinate calculation means calculates the horizontal distance (horizontal separation) and the vertical distance (vertical separation) from the laser distance measuring means to the object to be measured, based on the distance to the object to be measured and the direction of laser irradiation. An output control means that outputs an approach warning indicating that the obstacle is approaching, or a danger warning indicating that a worker is trapped between the handrail of the lifting bucket and the obstacle, in accordance with the calculation result by the coordinate calculation means. The system includes an output means that outputs the proximity warning or the danger warning in accordance with the control of the output control means, The laser rangefinder is installed on the handrail and irradiates a laser into a vertical or substantially vertical plane including the handrail. The output control means causes the output means to output the proximity warning when the horizontal distance is within a predetermined horizontal range and the vertical distance is within a predetermined vertical approach range. Furthermore, the output control means, after the output of the proximity warning by the output means and before a predetermined elapsed time threshold has elapsed, if the horizontal distance is within the horizontal range and the vertical distance is within a predetermined dangerous vertical range, causes the output means to output the danger warning. The aforementioned horizontal range is defined by the lower horizontal distance and the upper horizontal distance from the laser range measuring means. The aforementioned approach vertical range is determined by the lower vertical distance and the upper vertical distance from the laser range measuring means. The aforementioned dangerous vertical range is defined by the lower and upper vertical distances from the laser ranging means, and the upper vertical distance related to the dangerous vertical range is set to a value smaller than the lower vertical distance related to the approaching vertical range. An obstacle detection device characterized by the following features.

3. A device for detecting obstacles above a lifting bucket while it is rising, A laser rangefinder that measures the distance to an object by irradiating a laser radially into a vertical or nearly vertical plane, A coordinate calculation means calculates the horizontal distance (horizontal separation) and the vertical distance (vertical separation) from the laser distance measuring means to the object to be measured, based on the distance to the object to be measured and the direction of laser irradiation. An upward determination means for determining the upward movement of the lifting bucket based on the results of the laser distance measuring means which are measured repeatedly, An output control means that outputs an approach warning indicating that the obstacle is approaching, in accordance with the calculation result by the coordinate calculation means, The system includes an output means that outputs the proximity warning in accordance with the control of the output control means, The upward determination means determines that the lifting bucket is rising when the vertical separation decreases due to repeated measurements by the laser distance measuring means. The output control means causes the output means to output the proximity warning when the rise determination means has determined that the lifting bucket is rising, and the horizontal distance is within a predetermined horizontal range and the vertical distance is within a predetermined vertical approach range. The aforementioned horizontal range is defined by the lower horizontal distance and the upper horizontal distance from the laser range measuring means. The aforementioned approach vertical range is set by the lower vertical distance and the upper vertical distance from the laser range measuring means. An obstacle detection device characterized by the following features.

4. The upward determination means calculates the upward speed of the lifting bucket based on repeated measurements by the laser distance measuring means, and determines that the lifting bucket is rising when the upward speed of the lifting bucket exceeds a predetermined speed threshold. The obstacle detection device according to claim 3.

5. As a part of the floor of the lifting bucket slides, the floor surface of the lifting bucket expands. The system further includes a floor surface state setting means for setting either a normal state before a part of the floor body slides, or an extended state after a part of the floor body slides. When the extended state is set by the floor surface state setting means, the horizontal range is set based on an upper limit horizontal distance that is set to a value greater than the upper limit horizontal distance for the normal state. An obstacle detection device according to any one of claims 1 to 3.

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