Crane obstacle detection system

Abstract

To provide a crane obstacle detection system that can prevent accidents such as collisions between obstacles in a crane work area and a load lifted by the crane, including during movement of the load.SOLUTION: A crane obstacle detection system creates a 3D map of the area around the crane by synthesizing data acquired in real time from a plurality of 3D range sensors 21, 22, 23, and 24 mounted on the crane, and searches the 3D map for data that could be an obstacle in the direction of movement of the load from the current position of the load based on the shape of the load. If any data that could be an obstacle is found, the system notifies the crane control PLC 1 of the obstacle information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an obstacle detection system for a crane that prevents accidents such as collisions between obstacles in a crane work area and a load lifted by the crane. [Background technology]

[0002] In the past, in order to prevent accidents such as collisions between obstacles in a crane work area and the load lifted by the crane, it has been proposed to use a distance sensor to determine the distance to the obstacle, calculate the object's moving speed based on the change in distance over time, and obtain the relative speed of the crane to perform collision prevention control (see, for example, Patent Document 1). Incidentally, the technology disclosed in Patent Document 1 aims to prevent collisions by measuring the relative speed and the distance to the obstacle. The collision prevention was aimed at preventing the crane itself from colliding with the obstacle. For this reason, no consideration was given to the load lifted by the crane, and there was a problem that the problem of collisions with obstacles could not be solved, especially when the load was large.

[0003] In consideration of this problem, the applicant of the present application previously proposed a device for preventing collision with obstacles by obtaining information on the shape of the load suspended by the crane using a range sensor, calculating a deceleration distance for preventing a collision with an obstacle while traveling by adding the information on the shape of the load to the deceleration distance when the crane is unloaded, and slowing down the crane based on this deceleration distance (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-71455 A [Patent Document 2] JP 2019-127375 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention aims to provide an obstacle detection system for a crane that further develops the technology disclosed in Patent Document 1, making it possible to prevent accidents such as collisions between obstacles in the crane work area and the load lifted by the crane, including while the load is being moved. [Means for solving the problem]

[0006] In order to achieve the above object, the obstacle detection system of the present invention comprises: A collision prevention system for a crane whose operation is controlled by a crane control PLC, The current position of the load is calculated from the crane's travel position, traverse position, and load height obtained in real time from the crane control PLC, and the direction of load movement is calculated from the crane's travel speed, traverse speed, and load hoisting speed. By synthesizing data acquired in real time from multiple 3D range sensors attached to the crane, a 3D map of the area around the crane is created. Based on the shape of the load, a 3D map is searched for data that could be an obstacle in the direction of the load's movement from the load's current position. If there is any data that could cause an obstruction, the obstruction information is sent to the crane control PLC. The present invention is characterized in that:

[0007] In this case, the multiple 3D range sensors can be mounted facing the lateral direction of the crane and can consist of 3D range sensors that acquire data in the downward direction of the saddle and in the central direction of the girder from the left and right saddles, respectively, so as to face each other.

[0008] In addition to the multiple three-dimensional range sensors, a three-dimensional range sensor that points in the travel direction of the crane can be attached.

[0009] The multiple 3D range sensors can also be mounted facing in the travel direction of the crane and can comprise 3D range sensors that respectively acquire data in the forward upward direction of the crane, the left side of the load in the downward direction of the crane, the right side of the load in the downward direction of the crane, and the backward upward direction of the crane.

[0010] In addition to the multiple three-dimensional range sensors, a three-dimensional range sensor that orients the travel direction of the crane across the load can be attached.

[0011] In addition, a three-dimensional range sensor oriented in the travel direction of the crane can be attached so that the front direction of the sensor is oriented in the travel direction.

[0012] Also, the monitoring area of ​​the three-dimensional range sensor can be divided into upper and lower parts, and a three-dimensional range sensor can be assigned to each divided monitoring area.

[0013] In addition, the shape of the load can be assumed to be a cylinder that is created by rotating an object of that size around a vertical axis based on the actual height, width and depth of the load, and data that may be an obstacle can be searched for.

[0014] Furthermore, when searching for the data that may be an obstacle, a warning area that includes a danger area in addition to the shape of the suspended load can be used. Effect of the Invention

[0015] According to the crane obstacle detection system of the present invention, data obtained in real time from multiple 3D range sensors mounted on the crane is synthesized to create a 3D map of the area around the crane, and the 3D map is searched for data that could be an obstacle in the direction of movement of the load from the current position of the load based on the shape of the load. If any data that could be an obstacle is found, the obstacle information is notified to the crane control PLC, thereby making it possible to prevent accidents such as collisions between obstacles in the crane work area and the load lifted by the crane, even while the load is moving. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is an explanatory diagram of a device configuration (first embodiment) of a crane collision prevention control system according to the present invention. [Diagram 2] FIG. 4 is an explanatory diagram showing a method for determining the shape of a load in the crane collision prevention control system of the present invention. [Diagram 3] FIG. 2 is an explanatory diagram showing a crane operation speed pattern of the crane collision prevention control system of the present invention. [Figure 4] FIG. 2 is an explanatory diagram showing the amount of movement of each axis of a load of a crane in the crane collision prevention control system of the present invention. [Diagram 5] 1 shows the movement trajectory of a load suspended by a crane in the crane collision prevention control system of the present invention, where (a) is an explanatory diagram assuming a case in which a load is transported to a diagonal position on the floor surface of a rectangular building, (b) is the vertical plane movement trajectory, (c) is the horizontal plane movement trajectory, and (d) is a movement trajectory synthesized from (b) and (c) and shown in an overhead view. [Figure 6] FIG. 2 is an explanatory diagram showing a velocity vector of a load of a crane in the crane collision prevention control system of the present invention. [Figure 7] FIG. 2 is an explanatory diagram showing a warning area during crane movement of the crane collision prevention control system of the present invention. [Figure 8] 1 is an explanatory diagram showing a projection image during hoisting and lowering operations in the crane collision prevention control system of the present invention. FIG. [Figure 9] FIG. 2 is an explanatory diagram showing a projection image during combined hoisting, lowering, traveling, and traversing movements in the crane collision prevention control system of the present invention. [Figure 10] FIG. 2 is an explanatory diagram showing a projection image during traveling or traversing operation in the crane collision prevention control system of the present invention. [Figure 11] FIG. 2 is an explanatory diagram showing a projection image from the side during combined hoisting, lowering, traveling, and traversing movements in the crane collision prevention control system of the present invention. [Figure 12]FIG. 2 is an explanatory diagram showing a projection image during combined hoisting, lowering, traveling, and traversing movements in the crane collision prevention control system of the present invention. [Figure 13] FIG. 4 is an explanatory diagram showing the operation at the time of collision determination in the crane collision prevention control system of the present invention. [Figure 14] FIG. 11 is an explanatory diagram showing obstacle data to be deleted in the crane collision prevention control system of the present invention. [Figure 15-1] 1 is an explanatory diagram showing the arrangement position and monitoring area of ​​a three-dimensional range sensor in a crane collision prevention control system according to the present invention (first embodiment). FIG. [Figure 15-2] 1 is an explanatory diagram showing the arrangement position and monitoring area of ​​a three-dimensional range sensor in a crane collision prevention control system according to the present invention (first embodiment). FIG. [Figure 16-1] FIG. 2 is an explanatory diagram showing the arrangement position and monitoring area of ​​a three-dimensional range sensor in the crane collision prevention control system of the present invention (second embodiment). [Figure 16-2] FIG. 2 is an explanatory diagram showing the arrangement position and monitoring area of ​​a three-dimensional range sensor in the crane collision prevention control system of the present invention (second embodiment). [Figure 17] 1 is an explanatory diagram of a blind spot that occurs due to obstruction by a suspended load in the crane collision prevention control system of the present invention. FIG. [Figure 18] 1 is an explanatory diagram of a blind spot caused by an obstacle in the crane collision prevention control system of the present invention. FIG. [Figure 19] 1 is an explanatory diagram of a case where a monitoring area is divided by two 3D range sensors in a case where the vertical viewing angle of the 3D range sensors is narrow in the crane collision prevention control system of the present invention. FIG. [Figure 20] 1A and 1B are explanatory diagrams of the distribution of detection positions when the monitoring area is divided by two 3D range sensors in the crane collision prevention control system of the present invention when the vertical viewing angle of the 3D range sensors is narrow. [Figure 21] FIG. 2 is an explanatory diagram of a device configuration (second embodiment) of a crane collision prevention control system according to the present invention. [Figure 22]FIG. 10 is an explanatory diagram showing how the crane collision prevention control system of the present invention eliminates blind spots caused by obstructions by a suspended load. [Diagram 23] 1 is an explanatory diagram of minimizing blind spots caused by obstacles in the crane collision prevention control system of the present invention. FIG. [Figure 24] FIG. 13 is an explanatory diagram illustrating the possibility of overlapping detection areas in the crane collision prevention control system of the present invention. [Diagram 25] 4 is an explanatory diagram of a detection area required for a three-dimensional range sensor during high-speed traveling in the crane collision prevention control system of the present invention. FIG. [Figure 26] FIG. 13 is an explanatory diagram of the arrangement of 3D range sensors that can detect from near the crane at low speeds to far away at high speeds with a small number of 3D range sensors by adding the detection area required when traveling at high speeds in the crane collision prevention control system of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a crane collision prevention control system according to the present invention will be described with reference to the drawings.

[0018] The crane collision prevention control system of the present invention, as shown in FIG. 1 (first embodiment), is a crane collision prevention system whose operation is controlled by a crane control PLC (Programmable Logic Controller) 1, which synthesizes data acquired in real time from multiple 3D range sensors 21, 22, 23, 24 mounted on the crane to create a 3D map of the area around the crane, searches the 3D map for data that could be an obstacle in the direction of movement of the load from the current position of the load based on the shape of the load, and if any data that could be an obstacle is found, notifies the crane control PLC 1 of the obstacle information, thereby preventing accidents such as collisions between obstacles in the crane work area and the load lifted by the crane, including while the load is moving.

[0019] [Equipment configuration] The number and arrangement of the multiple 3D range sensors 21, 22, 23, 24 are not particularly limited as long as they can comprehensively detect obstacles in the crane work area, but for example, as shown in Figures 15-1 and 15-2 (first embodiment), the 3D range sensors 21, 22, 23, 24 can be installed facing the direction of travel of the crane, and can be configured as four 3D range sensors 21, 22, 23, 24 that acquire data in the upward direction of the crane's forward movement, the left side of the load in the downward direction of the crane, the right side of the load in the downward direction of the crane, and the upward direction of the crane's reverse movement, respectively. Three-dimensional range sensor 21 acquires data in the upward forward direction of the crane, three-dimensional range sensor 22 acquires data in the downward direction of the crane on the left side of the load, three-dimensional range sensor 23 acquires data in the downward direction of the crane on the right side of the load, and three-dimensional range sensor 24 acquires data in the upward backward direction of the crane. The three-dimensional range sensors 21, 22, 23, and 24 can be arranged so as to be suspended from a club trolley (or girder) via an arm, and in this embodiment, the three-dimensional range sensors 21, 22 and the three-dimensional range sensors 23, 24 are arranged in diagonal positions on the club trolley. Thereby, the three-dimensional range sensors 21, 22, and 23 cover a monitoring range when the crane is moving forward, and the three-dimensional range sensors 22, 23, and 24 cover a monitoring range when the crane is moving backward. In this case, by orienting the three-dimensional range sensors 21, 22, 23, and 24 so that their front direction, which allows them to maximize their capabilities, faces the direction of travel, it becomes possible to detect long distances and also to handle high-speed travel. Here, if the monitoring range of the 3D range sensor is blocked due to problems such as the structure of the crane, the problem of the monitoring range can be solved by adding sensors as appropriate and using five or more 3D range sensors.

[0020] In addition, the multiple 3D range sensors 21, 22, 23, 24 can also be configured as 3D range sensors 21, 22, 23, 24 that are mounted facing the lateral direction of the crane and acquire data in the downward direction of the saddle and in the central direction of the girder, respectively, as shown in Figures 16-1 and 16-2 (second embodiment). That is, the 3D range sensor 21 is placed in the center of the left saddle of the crane in a position where the sensor front faces the direction of the opposing saddle, and a depression angle is given so that the area directly below the saddle is illuminated, and the 3D range sensor 22 is placed in the center of the left saddle below the 3D range sensor 21 in a position where the sensor front faces the direction of the opposing saddle, and a depression angle is given to the 3D range sensor 22 so that the field of view of the 3D range sensor 22 contacts the field of view of the 3D range sensor 21, allowing the floor surface in the center of the crane to be illuminated from the saddle in an overhead view. The right saddle on the opposite side can be similarly arranged so that the fields of view of the two 3D range sensors 23, 24 contact each other. The three-dimensional range sensors 21, 22, 23, and 24 are suspended from the left and right saddles via arms. In this embodiment, the three-dimensional range sensors 21 and 22 and the three-dimensional range sensors 23 and 24 are arranged separately on the left and right saddles. Furthermore, the three-dimensional range sensors 21, 22, 23, and 24 can be disposed on the center line of the crane (girder direction, traveling direction), and can also be disposed offset in the traveling direction.

[0021] The three-dimensional range sensors 21, 22, 23, and 24 are connected to personal computers 31 and 32 which perform various calculation processes, and the personal computers 31 and 32 are further connected to a crane control PLC 1. A general-purpose three-dimensional range sensor can be used for the three-dimensional range sensors 21, 22, 23, and 24. In this example, we use the three-dimensional range sensor "Model No. YVT-35LX-F0" manufactured by Hokuyo Denki Co., Ltd. (capable of three-dimensionally detecting objects within a range of 210° horizontally and 40° vertically).

[0022] [Position and direction of movement of the load] The current position of the load is calculated from the crane's travel position, traverse position, and load height obtained in real time from the crane control PLC 1, and the movement direction of the load is calculated from the crane's travel speed, traverse speed, and hoisting speed of the load.

[0023] [Creating 3D data] Data from multiple 3D range sensors 21, 22, 23, and 24 attached to the crane is acquired in real time, and the acquired data is synthesized to create a 3D map of the current area around the crane.

[0024] [Detection of obstacle contact with suspended load] A 3D map is searched for data that may be an obstacle in the direction of movement of the load from the current position of the load. If any data that may be an obstacle is found, the obstacle information is notified to the crane control PLC 1.

[0025] [Shape of the load] The shape of a suspended load is determined by the height H, diameter (W) and width (W) of the load when the load is rotated around a vertical axis, based on its actual height H, width W and depth D, as shown in Figure 2. 2 +D 2 ) 1 / 2 The shape of the object is assumed to be cylindrical, and the data that causes the problem is searched for. Here, the actual height H, width W and depth D of the load can be input from the load information, or the load information can be added to the transport command information that instructs the crane on the origin and destination and automatically transmitted / received. Also, the height H, width W and depth D of the load can be measured using the three-dimensional range sensors 21, 22, 23, and 24. The area used for the load to contact an obstacle may include a danger area to provide a safety margin for the shape of the load. In other words, the area obtained by adding the danger area to the shape of the load can be used as the alert area, and when searching for data that may be an obstacle in determining whether the load will come into contact with an obstacle, the alert area obtained by adding the danger area to the shape of the load can be used. Here, the alert area can be set to a range of about 105% to 120% of the shape of the load depending on the situation in which the crane is used.

[0026] [Obstacle detection] First, from the current position of the load obtained from the crane control PLC 1, a search is made for data that may be an obstacle in the direction of travel of the load also obtained from the crane control PLC 1 from a 3D map created from data obtained from the 3D range sensors 21, 22, 23, and 24.

[0027] As shown in Figure 5(a), the robot delivers luggage to the diagonal corners of the floor of a rectangular building. The following describes this case. As an example of a case in which the motors for travel, traverse, and hoisting are operated in parallel to transport a load in the shortest possible time, and diagonal movements are frequently used, a specific example will be given of a load moving 18.0 m in the travel direction (vertical direction), 7.3 m in the traverse direction (horizontal direction), and rising from a height of 2 m to a height of 4 m, and then descending to a height of 2 m, using the speed pattern shown in Figure 3. In this case, the amount of movement of each axis is as shown in FIG. Here, the horizontal axis is the position in the direction of travel, and Figures 5(b) and (c) show the change in position in the height direction (vertical movement path) and the change in position in the lateral direction (horizontal movement path), while Figure 5(d) is a bird's-eye view created by combining Figures 5(b) and (c). In Figure 5(d), the load passes through the position marked with a black circle and arrives at the destination. (A) When the crane begins operating, it activates the motors on the three axes for travel, traverse, and hoisting, and moves diagonally from the bottom right position in Figure 5(d) to the upper left while lifting the load. (B) When it reaches the center of the traverse direction, the traverse and winding are stopped and it moves only by traveling. (C) When it gets close to the destination, the motors for traveling, traverse, and winding are operated again to move while lowering the cargo diagonally downward to the left, and it reaches the destination. Moreover, the moment-to-moment moving speed and direction of the load are expressed by a velocity vector that combines the speeds of the three axes: traveling, traversing, and hoisting, as shown in Fig. 6. The magnitude and direction change depending on the magnitude and polarity of the speed of each axis.

[0028] [Load shape and warning area] Since the warning area during crane movement must be determined to detect contact with obstacles on the expected path, in addition to the warning area described in Figure 1, as shown in Figure 7, the center of the load is moved along a speed vector which is a composite of the moment-to-moment speeds of each axis of travel, traverse and hoisting, and the end point is a point a distance (warning distance) taking into account the braking distance to stop the load at that speed and the margin to the obstacle (including the sway of the load), and the center of the load is placed at the start point, midpoint and end point, and an envelope connecting the outer edges of the warning area is drawn.

[0029] [Obstacle location] Obstacles are detected as collisions with objects within the warning area and warning distance in the direction of travel from the lifted load. The surveillance area can be expanded according to the surveillance distance. Specifically, the surveillance area can be set in a trumpet shape, with the angle (surveillance angle) increasing as the area gets farther away, as shown in FIG. Conversely, the angle (warning angle) can be set in a funnel shape that narrows the further away it is. This is to absorb detection errors caused by the sensor's characteristics making the resolution poorer at longer distances, and by minute fluctuations in the sensor's monitoring range caused by the crane's meandering. The warning angle can be set, for example, within a range of about ±5° depending on the sensor's performance and the crane's meandering characteristics.

[0030] [Contact judgment] Contact between the load and an obstacle is determined to be occurring when an obstacle is displayed within the warning area / warning distance of the load, and by notifying the crane control PLC 1 of the obstacle information, accidents such as collisions between obstacles in the crane work area and the load lifted by the crane are prevented, even while the load is being moved. Fig. 8 shows a projection image during winding and lowering operations, Fig. 9 shows a projection image during combined movements of winding, lowering, traveling and lateral movement, Fig. 10 shows a projection image during traveling or lateral movement, Fig. 11 shows a projection image from the side during combined movements of winding, lowering, traveling and lateral movement, Fig. 12 shows a projection image during combined movements of winding, lowering, traveling and lateral movement, and Fig. 13 shows the operation during contact detection. As shown in FIG. 11, the surveillance area can be set in a trumpet shape, in which the angle (surveillance angle) becomes wider the further away it is, or conversely, in a funnel shape, in which the angle becomes narrower. The surveillance stop area is determined by adding the surveillance angle to the surveillance area width, the length to the surveillance distance, the surveillance area width, and the height from the center position of the lifted load in the direction of travel of the load.

[0031] [Delete Obstacle Data] When considering the operation of lifting a load, since there are hooks for hoisting the load, specialized slings for each load, wires, etc. in the direction of movement of the load (upward), it is necessary to prevent these from becoming obstacles and causing the load to stop. Specifically, as shown in Fig. 14, since the load, hooks for hoisting the load, wires, etc. are detected in the data measured by the 3D range sensors 21, 22, 23, and 24, these data are deleted from the data measured by the 3D range sensors 21, 22, 23, and 24.

[0032] [When the monitoring range is blocked by the position of the suspended load] In the arrangement position (first embodiment) of the 3D range sensor shown in Fig. 15-1 and Fig. 15-2, due to structural reasons, a situation occurs in which the monitoring range of the 3D range sensor is blocked by the position of the suspended load, creating a blind spot, as shown in Fig. 17(a)-(b). For example, when the suspended load is lifted to a height close to the 3D range sensor 21, the light beam of the 3D range sensor 21 is blocked by the suspended load, creating a blind spot diagonally forward. To address this issue, as shown in Figure 17(c), a 3D range sensor 25 that senses in the same direction as the 3D range sensor 21 can be added at a position on the opposite side of the load from the 3D range sensor 21, for example, at a position near the 3D range sensor 24, to eliminate the problem of blind spots in the monitoring range (the same applies in the reverse direction).

[0033] [When the monitoring range is blocked by an obstacle] 18(a)-(b), for structural reasons, a situation may occur in which the monitoring range of the 3D range sensor is blocked by an obstacle, creating a blind spot. When a three-dimensional movement path of the load shown in FIG. 18(a)-(b) is planned, a blind spot is created in the monitoring area of ​​the 3D range sensor 21 due to the obstacle blocking the movement. To address this issue, as shown in FIG. 18(c), the problem of blind spots occurring in the monitoring range can be eliminated by adding a 3D range sensor 25 that senses in the same direction as 3D range sensor 21 in a position near 3D range sensors 22 and 24, for example, in a position near 3D range sensor 24 (the same applies to the reverse direction).

[0034] [Dividing the monitoring area by the field of view of the sensor] Regarding the monitoring area of ​​the 3D range sensor 21, as shown in Figure 15-1, it is desirable for one 3D range sensor 21 to be able to cover from the floor surface to the underside of the crane, but 3D range sensors currently in practical use are limited in that the viewing angle in the vertical direction is approximately 40 degrees. If a larger field of view is required, for example if the lifting height of the crane needs to exceed 10m and reach approximately 20m, then as shown in FIG. 19, the monitoring area of ​​3D range sensor 21 can be divided into upper and lower halves, and two 3D range sensors 21A and 21B can be used to assign the divided monitoring areas to each, specifically, by assigning 3D range sensor 21A to the monitoring area with the upper field of view, and 3D range sensor 21B to the monitoring area with the lower field of view (the same applies to the reverse direction).

[0035] [Distribution of detection positions when obstacle sensors are pointed in the direction of travel] FIG. 20 shows the distribution of detected position information (point cloud) of obstacles obtained by two three-dimensional range sensors 21A and 21B. In this way, the monitoring areas of the two 3D range sensors 21A and 21B are substantially adjacent but do not overlap, so that the obstacle detection in each area is performed independently. By overlapping the monitoring areas of the three-dimensional range sensors 21A and 21B, the reliability of detection can be improved. Although the use of two 3D range sensors 21A and 21B increases the number of 3D range sensors required, the number can be reduced by, for example, providing a mechanism for switching the sensing direction of the 3D range sensor between the forward direction and the reverse direction.

[0036] On the other hand, in the arrangement position of the 3D range sensor shown in Figures 16-1 and 16-2 (second embodiment), the 3D range sensors 21, 24 are oriented in a bird's-eye view toward the center of the crane, and the monitoring area is from the floor to about 3 m below the bottom of the girder. If there is an obstacle that exceeds the range from the bottom of the girder to the bottom of the hook and the suspended load, the crane cannot be operated, and if an obstacle from the floor can be monitored at a point a distance below this height that takes safety margins into consideration, collisions can be avoided, so even if it is outside the field of view of the sensor, the impact is small. The 3D range sensors 21 and 24 have overlapping monitoring areas up to the floor surface, except for the upper limit of their respective fields of view, which is determined by the viewing angles of the 3D range sensors, so that even if the view of one sensor is blocked by a suspended load or an obstacle, the other sensor can continue monitoring. In addition, since the detection distance of each of the 3D range sensors 21 and 24 is longest in the actual situation in the forward direction, as shown in the figure, the monitoring area of ​​the 3D range sensor 21 reaches the area of ​​the 3D range sensor 23, and therefore the monitoring area of ​​the 3D range sensor 23 can also overlap with the monitoring area of ​​the 3D range sensor 21 except for the upper part. For example, if a load moves into the monitoring area of ​​the 3D range sensor 23, the area directly below the load becomes a blind spot of the 3D range sensor 23, but the 3D range sensor 21 can capture the situation below the load. The same is true for the 3D range sensors 22 and 24. Because the 3D range sensor has a viewing angle of more than 180 degrees, a single unit can monitor the forward and reverse directions of the crane simultaneously without having to switch between them or turn the sensing direction of the 3D range sensor. Due to the characteristics of the 3D range sensor, the monitoring areas in the forward and reverse directions cannot achieve the same level of performance (detection distance) as the front direction, but a detection distance of about 70% can be achieved, making it possible to simultaneously monitor an area of ​​up to about 20 m from the crane in both the forward and reverse directions.

[0037] [Control configuration] As shown in FIG. 21, the control configuration in this embodiment is basically the same as the control configuration in the arrangement position (first embodiment) of the 3D range measurement sensor shown in FIG. 1 and FIG. 15-1 and FIG. 15-2. By changing the placement position and mounting direction of the 3D range sensors and arranging them in a direction that provides a wide 180-degree viewing angle along the direction of travel of the crane, the four 3D range sensors 21, 22, 23, and 24 can operate effectively at all times and simultaneously monitor the forward and reverse directions. In addition, in the case of a large crane with a large span, multiple units of the same configuration may be arranged in parallel on the saddle and girder to completely cover the space between the left and right rails.

[0038] [Operation when monitoring range is blocked by the position of the suspended load] When a load is lifted to a height close to the 3D range sensor 21, in the arrangement position (first embodiment) of the 3D range sensor shown in Figures 15-1 and 15-2, the light beam from the 3D range sensor 21 is blocked by the load, causing a blind spot to appear diagonally forward. Even in the arrangement of this embodiment, as shown in FIG. 22, a blind spot of the 3D range sensor 21 is created by the suspended load, but since this blind spot is covered by the detection areas of the 3D range sensors 23, 24 on the opposite side, the blind spot is eliminated by these 3D range sensors 23, 24.

[0039] [Operation when monitoring range is blocked by an obstacle] When planning a three-dimensional movement path, the placement position (first embodiment) of the three-dimensional range sensor shown in Figures 15-1 and 15-2 will be blocked by an obstacle, resulting in a blind spot in the monitoring area of ​​the three-dimensional range sensor 21, as shown in Figure 18. Even with the arrangement of this embodiment, as shown in Figure 23, a blind spot occurs in the monitoring area of ​​the three-dimensional range sensor 21. However, since this blind spot is almost completely covered by the detection areas of the opposite three-dimensional range sensors 23, 24, a slight blind spot remains on the side in the direction of travel of the obstacle (the distant side), but this area can be minimized by the three-dimensional range sensors 23, 24.

[0040] [Distribution of detection positions when the obstacle sensor is placed on the saddle and oriented perpendicular to the direction of travel] In the arrangement of this embodiment, the monitoring areas of the three-dimensional range sensors 21 to 24 overlap. Figure 24 shows the distribution of detection positions in a vertical section at a point 16 m away from the center of the crane in the traveling direction. Above a height of 20 m, the area below where only one sensor detects increases, but up to that point, there are many areas where multiple sensors detect each other overlappingly. This provides redundancy so that even if one 3D range sensor misses an obstacle, the other 3D range sensors can detect it and avoid a collision, thereby increasing safety. In addition, in the overlapping areas, even if one 3D range sensor fails, the other 3D range sensors can compensate, making it possible to continue operation, such as in a degraded mode. Since monitoring can be performed using multiple 3D range sensors, the performance (resolution and processing speed) of each 3D range sensor can be reduced, increasing the options for 3D range sensors and reducing the load on the computer.

[0041] In this way, by adopting the arrangement of this embodiment, the following advantages are obtained: Each of the four 3D range sensors 21 to 24 can simultaneously monitor the forward and backward directions. Blind spots caused by a suspended load can also be eliminated by using the 3D range sensor on the opposite side. Blind spots caused by obstacles in the path can also be reduced by using the 3D range sensor on the opposite side. Since multiple 3D range sensors can perform overlapping monitoring, the four 3D range sensors 21 to 24 can perform highly reliable monitoring. Larger cranes can be accommodated by arranging multiple units of this structure in parallel in the girder direction.

[0042] [Response to increasing driving speeds] If the directional characteristics of the 3D range sensor shown in FIG. 25(a) are cut out at 10 m to the left and right of the front axis, it will roughly have the shape shown in FIG. 25(b). Since the coverage area of ​​the sides of a 3D range sensor is reduced to approximately 70% of that of the front, there is a risk that the required detection distance (30 m) cannot be ensured at high speeds (e.g., 180 m / min). In order to achieve this with frontal detection in the arrangement position (first embodiment) of the 3D range sensor shown in Figures 15-1 and 15-2, it is necessary to increase the resolution and equip multiple 3D range sensors to eliminate blind spots. Specifically, a total of 12 sensors are required: 3 (for long distance + for close distance + for directly below) x 2 (to eliminate blind spots) x 2 (for forward and backward movement). Since high-speed travel is at a slight elevation or depression angle from a nearly horizontal direction, and since diagonal movement at a steep angle can be detected near the crane with the arrangement of this embodiment, the speed range that can be handled can be expanded by about 1.5 times (180 m / min) by adding a 3D range sensor 26 for long-distance monitoring at high speeds to the arrangement of this embodiment as shown in Fig. 26. In this case, the number of 3D range sensors will be a total of six, consisting of four 3D range sensors 21-24 + two 3D range sensors 26 for high-speed ranges (forward and backward). By adjusting the angle (mainly by adjusting the depression angle) of the 3D range sensor 26 for high-speed areas so that the detection characteristics shown in Figure 25 (b) match the area used for high-speed movement, it becomes possible to detect obstacles up to 30 m away when moving at high speed, and to detect obstacles in the vicinity (within approximately 15 m) without any blind spots when moving at medium to low speeds.

[0043] The above describes the crane collision prevention control system of the present invention based on its embodiments. However, the present invention is not limited to the configurations described in the above embodiments, and the configuration can be changed as appropriate without departing from the spirit of the invention. [Industrial Applicability]

[0044] The crane collision prevention control system of the present invention can prevent accidents such as collisions between obstacles in the crane work area and the load of the crane, including while the load is moving, and can therefore be widely applied to cranes whose operation is controlled by a crane control PLC, and can be effectively used industrially. [Explanation of symbols]

[0045] 1 Crane control PLC 21, 22, 23, 24 3D range sensor 21A, 21B 3D range sensor 25 3D range sensor (for long-distance monitoring) 26 3D range sensor (for long-distance monitoring at high speeds) 31, 32 PC

Claims

1. A collision prevention system for a crane that performs operation control by a crane control PLC, The current position of the load is calculated from the travel position, traverse position, and load height of the crane, which are acquired in real time from the crane control PLC, and the direction of movement of the load is calculated from the travel speed, traverse speed, and hoisting speed of the load of the crane. By synthesizing data acquired in real time from multiple 3D range sensors attached to the crane, a 3D map of the area around the crane is created. Based on the shape of the load, a 3D map is searched for data that may be an obstacle in the direction of movement of the load from the current position of the load, If there is data that may be an obstacle, the obstacle information is notified to the crane control PLC. An obstacle detection system for a crane, comprising:

2. The obstacle detection system for a crane as described in claim 1, characterized in that the multiple three-dimensional range sensors are mounted oriented in the lateral direction of the crane and are three-dimensional range sensors that acquire data in the downward direction of the saddle and the central direction of the girder from the left and right saddles, respectively, so as to face each other.

3. 3. The obstacle detection system for a crane according to claim 2, further comprising a three-dimensional range sensor oriented in the travel direction of the crane, in addition to the plurality of three-dimensional range sensors.

4. 2. The obstacle detection system for a crane as described in claim 1, wherein the plurality of three-dimensional range sensors are mounted facing in the travel direction of the crane and are three-dimensional range sensors which respectively acquire data in the forward upward direction of the crane, the left side of the load in the downward direction of the crane, the right side of the load in the downward direction of the crane, and the upward direction of the reverse movement of the crane.

5. 5. The obstacle detection system for a crane according to claim 4, further comprising, in addition to the plurality of three-dimensional range sensors, a three-dimensional range sensor that is oriented in the travel direction of the crane across a load.

6. 6. An obstacle detection system for a crane according to claim 3, 4 or 5, wherein the three-dimensional range sensor oriented in the travel direction of the crane is mounted so that the front direction of the sensor is oriented in the travel direction.

7. 6. The obstacle detection system for a crane according to claim 1, 2, 3, 4 or 5, wherein a monitoring area of ​​the three-dimensional range sensor is divided into upper and lower monitoring areas, and a three-dimensional range sensor is assigned to each divided monitoring area.

8. 6. An obstacle detection system for a crane as claimed in claim 1, 2, 3, 4 or 5, characterized in that the shape of the load is assumed to be a cylindrical shape created by rotating an object of said size around a vertical axis based on the actual height, width and depth of the load, and data that may be an obstacle is searched for.

9. 6. An obstacle detection system for a crane according to claim 1, 2, 3, 4 or 5, wherein when searching for data that may be an obstacle, a warning area obtained by adding a danger area to the shape of the load is used.

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