Crane monitoring device and crane

Abstract

To favorably monitor a specific portion of a crane.SOLUTION: In a monitoring device of a crane having a camera 39 for monitoring a specific portion 28 of a crane 20, the visual line of the camera 39 is moved such that the specific portion 28 approaches the center of an imaging range. Since the specific portion 28 can approach the center of the imaging range, photographing is performed while the specific portion 28 is moved to the center side with respect to the movement of the camera 39 and the specific portion 28 so that the periphery is favorably monitored. Further, since the influence of image distortion which may occur in an outer periphery of a photographed image can be suppressed, the monitoring is favorably performed.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a crane monitoring device.

Background Art

[0002] For monitoring the surroundings of a crane, it has been conventionally practiced to equip a monitoring camera at any location of the crane, image the monitoring area, and make it visually confirmable. A conventional crane monitoring device provides a camera capable of imaging a range including a hook at the tip of a boom, determines the distance of the hook from changes in the postures of the boom and the jib and changes in the amount of wire rope payout, and cuts out and displays the center of the imaged image (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above-described conventional crane monitoring device merely cuts out, enlarges or reduces, etc. the hook portion of the imaged image and displays it, resulting in a blurred image and there is a risk that sufficient monitoring cannot be performed.

[0005] An object of the present invention is to enable good monitoring.

Means for Solving the Problems

[0006] The present invention is a crane monitoring device having a camera for monitoring a specific part of a crane, wherein the line of sight of the camera is moved so that the specific part approaches the center of the imaging range.

Effects of the Invention

[0007] According to the present invention, it becomes possible to monitor the target of surveillance effectively. [Brief explanation of the drawing]

[0008] [Figure 1] This is a side view of a crane equipped with a monitoring device according to an embodiment of the present invention. [Figure 2] Figure 2(A) is a magnified side view of the area around the camera, and Figure 2(B) is a perspective view of the camera cover. [Figure 3] This is a block diagram showing the configuration of a crane terminal. [Figure 4] This shows the display screen for captured images in the Hook's image acquisition control. [Figure 5] This shows the display screen of the captured image when scaling processing is performed in the image acquisition control. [Figure 6] This is a flowchart for image acquisition control. [Figure 7] Figure 6 is a flowchart of the imaging control process. [Figure 8] This is an example of displaying the captured image before and after scaling, with each image displayed separately on a different screen. [Figure 9] This is a side view of a crane showing an example where the camera placement has been changed to monitor the counterweight. [Figure 10] Figure 9 shows an example of a display screen for images of the counterweight captured by the camera. [Modes for carrying out the invention]

[0009] [Crane Overview] Figure 1 is a side view of a crane equipped with a monitoring device according to an embodiment of the present invention. Here, crane 20 will be exemplified as a so-called mobile tower crane. In the following description of crane 20, the front as viewed from the upper slewing body 22 will be referred to as "front," the rear as viewed from the upper slewing body 22 as "rear," the left side as viewed from the upper slewing body 22 as "left," and the right side as viewed from the upper slewing body 22 as "right." Furthermore, in the following explanation, unless otherwise specified, the direction of each part will be described assuming that the front of the upper slewing body 22 and the front of the lower traveling body 21 are aligned.

[0010] As shown in the figure, the crane 20 is composed of a self-propelled crawler-type lower vehicle 21, an upper slewing vehicle 22 that is rotatably mounted on the lower vehicle 21, and a front attachment 23 that is tiltably attached to the front side of the upper slewing vehicle 22.

[0011] The upper rotating body 22 has a rotating frame 221 that extends in the forward and rearward directions. The base end of the tower boom 24, which will be described later, is attached to the front side of the rotating frame 221 in a way that allows it to be raised and lowered.

[0012] Furthermore, on the slewing frame 221, the base end of the mast 224, which will be described later, is rotatably mounted behind the mounting position of the tower boom 24. In addition, on the slewing frame 221, the base end of the backstop 225, which will be described later, is rotatably mounted behind the mounting position of the mast 224.

[0013] A counterweight 226, which balances the weight of the front attachment 23 and the suspended load, is positioned at the rear end of the slewing frame 221. A boom luffing winch and other equipment (not shown) are also positioned nearby. On the other hand, a cab 227, which houses the driver's seat and various operating devices (none of which are shown), is provided on the front right side of the slewing frame 221.

[0014] The front attachment 23 corresponds to the operating part of the crane 20, is provided on the upper slewing body 22, and transports loads such as materials between the ground and high places. The front attachment 23 includes a tower boom 24, a tower jib 25, and a tower strut 26.

[0015] The tower boom 24 is attached to the upper slewing body 22 so as to be able to rise and fall. The tower boom 24 is composed of a lower boom 241, an intermediate boom 242, and an upper boom 243. A jib hoisting winch 244 and a main hoist winch 245, which will be described later, are attached to the lower boom 241.

[0016] The tower jib 25 is attached to the front end side of the upper boom 243 so as to be able to rise and fall, and the tower strut 26 is attached to the upper end side of the upper boom 243 so as to be able to swing. Further, a tower guide sheave 247 and a guide sheave 248 are rotatably attached to the rear of the upper boom 243.

[0017] The tower jib 25 is composed of a lower jib 251, an intermediate jib 252, and an upper jib 253. Guide sheaves 254 and point sheaves 255 are rotatably attached to the tip side of the upper jib 253. The guide sheaves 254 and the point sheaves 255 are for winding the main hoist rope 256, which will be described later.

[0018] The tower strut 26 is swingably attached to the upper end side of the upper boom 243 of the tower boom 24. The tower strut 26 is a triangular structure. One end of a pendant rope 267 is connected to the upper part of the front end of the tower strut 26, and the other end of the pendant rope 267 is connected to the tip side of the upper jib 253 of the tower jib 25. Further, a boom side pendant rope 274, which will be described later, is connected to the upper part of the rear end of the tower strut 26.

[0019] The jib luffing winch 244 raises and lowers the tower jib 25 via the tower strut 26. The jib luffing winch 244 and the tower strut 26 are connected by a jib luffing rope 27. The jib luffing rope 27 consists of a winding rope 273 that is wound sequentially around multiple sheaves on the lower spreader 271 and multiple sheaves on the upper spreader 272 and then wound onto the jib luffing winch 244, and a boom-side pendant rope 274 that connects the upper spreader 272 and the tower strut 26. Therefore, by winding and unwinding the winding rope 273 using the jib luffing winch 244, the tower strut 26 swings, and the tower jib 25 is luffed via the pendant rope 267.

[0020] One end of the main hoisting rope 256 is wound around the main hoisting winch 245. The other end of the main hoisting rope 256 is attached to the load hook 28 (hereinafter referred to as hook 28) via guide sheaves 248, 254 and point sheave 255. Therefore, the hook 28 can be raised and lowered by winding and unwinding the main hoisting rope 256 using the main hoisting winch 245.

[0021] The backstop 225 is located between the slewing frame 221 and the lower boom 241 of the tower boom 24. This backstop 225 supports the upright tower boom 24 from behind.

[0022] The mast 224 is rotatably attached to the slewing frame 221 at its base. A boom spreader 228 is provided at the rotating end of the mast 224, and this boom spreader 228 is connected to the upper boom 243 via a pendant rope 229 of a certain length. The boom spreader 228 is also connected to a boom luffing rope 291, which is wound around a tower boom luffing winch (not shown) provided on the slewing frame 221.

[0023] Therefore, when the boom luffing rope 291 is wound up by the tower boom luffing winch, the tower boom 24 can be raised via the pendant rope 229. On the other hand, when the boom luffing rope 291 is unwound by the tower boom luffing winch, the tower boom 24 can be lowered (collapsed) towards the ground via the pendant rope 229.

[0024] [About the camera] A camera 39, with its line of sight directed downwards, is suspended and supported at the tip of the aforementioned tower jib 25. Figure 2(A) is an enlarged side view of the area around the camera 39, and Figure 2(B) is a perspective view of the cover 392 of the camera 39. Camera 39 targets the hook 28, a specific part located below, for imaging. Camera 39 images the hook 28 to monitor the area around the hook 28, monitor the hook 28 and the suspended load, and monitor instructions from the surroundings during the transport operation. Furthermore, the camera 39 is installed on a part of the tower jib 25, which is a moving component, and whose relative position to the hook 28 changes.

[0025] The camera 39 comprises a camera body 391 having an optical element for taking images and a light-receiving element, a cover 392 for housing the camera body 391, a movable part 393 for moving the line of sight of the camera body 391 within the cover 392, a grid 394 attached to the front side of the cover 392, a support column 395 provided on the back side of the cover 392, and a base 396 that supports the cover 392 via the support column 395.

[0026] The camera body 391 is equipped with a driveable optical element and can optically enlarge or reduce (zoom) the captured image. The camera body 391 also converts the captured image into data and outputs it to the controller 31, which will be described later.

[0027] The base 396 is fixedly mounted to the side of the upper jib 253 of the tower jib 25, near the tip. The upper end of the support column 395 is pivotably supported by the base 396, and the lower end is fixedly connected to the cover 392. The support column 395 is suspended by the base 396 so as to be pivotable by its own weight. Furthermore, the pivot axis of the support column 395 is parallel to the luffing pivot axis of the tower jib 25, and even when the tower jib 25 is luffing, it hangs down in a vertically downward direction due to its own weight.

[0028] The cover 392 is cylindrical, and its central axis is parallel to the support column 395. The front side of the cover 392 is open, and the support column 395 is connected to the rear side. Inside the cover 392, the camera body 391 is mounted via a movable part 393, facing forward. The camera body 391 has its line of sight in the reference orientation of the movable part 393 set parallel to the central axis of the cover 392. Therefore, in the reference orientation, the camera body 391 has its line of sight directed vertically downward. The movable part 393 can tilt the camera body 391 around two axes using two actuators, and the line of sight of the camera body 391 can be varied in two directions perpendicular to that line of sight. Furthermore, these two directions are also perpendicular to each other. Therefore, the camera body 391 can take images by directing its line of sight in any direction within the movable range of the movable part 393.

[0029] The grid 394 is attached to the front opening of the cover 392. The grid 394 may be made of mesh or a transparent plate with a grid pattern printed on it. The grid 394 is mounted so as to be perpendicular to the line of sight of the camera body 391 in its reference orientation, and is always included in the imaging range of the camera body 391. For example, by having the camera body 391 superimpose the grid 394 onto the hook 28 and image it, it can be used to determine whether or not the hook 28 is shaking and the magnitude of that shaking. In other words, the grid 394 functions as a reference member for determining the magnitude of the shaking of the hook 28.

[0030] [Crane control system] Figure 3 is a block diagram showing the configuration of the crane terminal 30. The crane terminal 30 is a control terminal mounted on the crane 20 and performs control of various operations of the crane 20. The crane terminal 30 is equipped with a controller 31 which includes a processing unit that has a CPU, memory devices such as ROM and RAM, and other peripheral circuits.

[0031] As shown in Figure 3, the controller 31 is connected to a load cell 321, a boom angle sensor 322, a maneuvering amount sensor 323, a jib angle sensor 324, a limit switch 325, an input unit 331, a display device 332, an alarm 341, a stop device 342, an operating lever 37, a control valve 38, and the camera body 391 and movable part 393 of the camera 39.

[0032] The load cell 321 detects the tension acting on the boom luffing rope 291 that raises and lowers the tower boom 24. The input unit 331 is, for example, a touch panel, and outputs control signals to the controller 31 in response to operations from the operator. Various settings can be made from the input unit 331. The boom angle sensor 322 detects the elevation angle (hereinafter also referred to as boom angle) of the tower boom 24. The jib angle sensor 324 detects the elevation angle of the tower jib 25 (hereinafter also referred to as the jib angle). The limit switch 325 notifies the controller 31 when the hook 28 is reeled in beyond a specified limit. The control amount sensor 323 detects the amount of operation of the control lever 37.

[0033] The display device 332 displays, for example, information such as the suspension load and working posture, and images captured by the camera 39 on its display screen. The alarm device 341 generates an alarm based on the control signal output from the controller 31. The stopping device 342 stops the operation of hydraulic motors (not shown) connected to the main hoist winch 245 and the jib luffing winch 244, respectively, based on control signals output from the controller 31. The stopping device 342 is, for example, an electromagnetic switching valve capable of cutting off the supply of pressurized oil from the hydraulic pump to the hydraulic motor.

[0034] The controller 31 calculates the lifting load applied to the hook 28 based on the outputs of the load cell 321 and the boom angle sensor 322. If the lifting load is equal to or greater than the rated total load, it outputs a stop signal to the stop device 342 and an alarm signal to the alarm device 341. Furthermore, when the controller 31 receives notification from the limit switch 325, it outputs a stop signal to the stop device 342 and an alarm signal to the alarm device 341. Furthermore, the controller 31 controls each of the valves that make up the control valve 38 in response to the operation of the operating lever 37, thereby executing various operations of the crane 20.

[0035] In the example of the crane terminal 30 described above, a configuration was shown in which the abnormality processing configuration, such as the load cell 321, boom angle sensor 322, maneuver amount sensor 323, jib angle sensor 324, limit switch 325, alarm 341, and stop device 342, and the normal operation configuration, such as the operating lever 37 and control valve 38, are controlled by a unified control system. However, the abnormality processing configuration and the normal operation configuration may be configured to have separate controllers for each, forming separate systems. Furthermore, while the image capture control by camera 39, which will be described later, is shown as an example of a configuration controlled by a unified control system, the image capture control may also be performed by a separate, independent controller.

[0036] [Crane monitoring device] The camera 39 and controller 31 described above constitute a monitoring system for the crane. The following describes various control and processing functions of the monitoring system using the camera 39.

[0037] The hook 28, which is imaged by the camera body 391, may sway due to the lifting and lowering of the hook 28, the luffing and lowering of the tower boom 24 and tower jib 25, the rotation of the upper slewing body 22, etc., or the hook 28 itself may move. As a result, monitoring may become difficult as the hook 28 may move outside the imaging range of the camera body 391, or the image of the hook 28 may become small. With conventional cranes, in order to monitor the hook 28, the operator had to operate the crane while simultaneously adjusting the position of the moving hook 28 within the imaging range, making crane operations difficult. To address this, the controller 31 performs tracking control so that the camera body 391's line of sight follows the hook 28 and captures images.

[0038] Figure 4 shows the display screen of the captured image during the image acquisition control of hook 28, and Figure 5 shows the display screen of the captured image during the scaling process in the image acquisition control. Figures 6 and 7 are flowcharts of the image acquisition control. Based on these points, we will explain the imaging control in detail. In the following explanation, it is assumed that the captured image and the captured area are the same.

[0039] First, the controller 31 initially starts imaging with the camera body 391 in a reference orientation (Figure 6: Step S1), and displays the captured image on the display device 332 (Figure 6: Step S3). Next, the image of the hook 28 in the captured image is detected (Figure 6: Step S5). For detecting the hook 28, pattern matching, detection of hook images obtained by machine learning, or other well-known detection methods may be used.

[0040] When a hook 28 is detected, a frame W surrounding the outer edge of the hook 28 is displayed in the captured image, as shown in Figure 4 (Figure 6: Step S7). The frame W consists of a rectangle whose four sides are close to the outer edge of the detected hook 28. Displaying the frame W facilitates the recognition of the hook 28 within the display screen and also facilitates the process of obtaining the center of the hook 28, but the display process of the frame W is not mandatory.

[0041] The controller 31 performs tracking control to control the movable part 393 so that the camera body 391's line of sight is always facing the hook 28 and the hook 28 is positioned in the center of the imaging range. Furthermore, several execution conditions can be set for the execution of follow-up control, as listed below. For example, the execution conditions for follow control include "always follow setting," "follow setting during expansion / contraction," "non-follow setting during rotation," "follow setting during elevation / deceleration," and "follow setting during hook raising / lowering." These various settings can be selected and configured in advance from the input unit 331 mentioned above.

[0042] The "Always Follow Setting" is the setting for unconditional follow control. The "Expand / Retract Tracking Setting" is a setting for when tracking control is performed when the operation of expanding or retracting the captured image is manually input from the input unit 331. Furthermore, the "Scaling Tracking Setting" described above may be configured to perform tracking control only when the captured image is enlarged, and not when it is reduced.

[0043] The "Non-following during rotation setting" is a setting that prevents follow control from being performed while the upper rotating body 22 is rotating due to the operation of the control lever 37. During rotation, the hook 28 may experience significant shaking. If imaging and display are performed while tracking the hook 28, it may become difficult to monitor the surrounding environment, and dizziness may occur. The "Non-tracking during rotation setting" is a setting to avoid these problems.

[0044] The "Looping / Rolling Follow-Up Setting" is a setting used when follow-up control is performed when the tower boom 24 or tower jib 25 is luffed or rotated by operating the control lever 37. The "Hook Lifting / Lowering Follow-Up Setting" is a setting for when follow-up control is performed when the hook 28 is lifted or lowered by operating the control lever 37.

[0045] When a frame W appears on the hook 28 in the aforementioned captured image, the controller 31 determines whether or not the "continuous tracking setting" is set in the execution conditions for the various tracking controls described above (Figure 6: Step S9). If the "always-on tracking setting" is enabled, the controller 31 promptly performs an automatic image scaling process to optimize the size of the hook 28 displayed in the captured image (Figure 6: Step S11). In the automatic image scaling process, for example, if the hook 28 in the captured image in Figure 4 is smaller than the appropriate size, the zoom function of the camera body 391 is used to adjust the image to one where the hook 28 is enlarged, as shown in Figure 5. Conversely, if the hook 28 in the captured image is larger than the appropriate size, the image is adjusted to one where the hook 28 is reduced in size.

[0046] In the automatic image scaling process, the controller 31 calculates the ratio of the area of ​​the frame W to the entire captured image and compares the calculated ratio with a predetermined ratio. If the calculated ratio is smaller than the predetermined ratio, the controller 31 controls the camera body 391 to enlarge the image magnification to achieve the predetermined ratio. If the calculated ratio is larger than the predetermined ratio, the controller 31 controls the camera body 391 to reduce the image magnification to achieve the predetermined ratio. In addition, in the automatic scaling process, the area of ​​the hook 28 may be calculated instead of the area of ​​the frame W to determine the ratio to the entire captured image. Furthermore, the frame W expands or contracts in accordance with the size of the hook 28 as the captured image expands or contracts.

[0047] As shown in Figures 4 and 5, the grid 394 is visible in the captured image, and by comparing the width of one square of the grid 394 with the hook 28, the magnitude of the shaking occurring in the hook 28 can be visually recognized. The grid 394 is captured together with the hook 28, and the image of the grid 394 captured within the image functions as a vibration indicator that displays the magnitude of the vibration of the hook 28 in a recognizable manner.

[0048] Then, the controller 31 performs follow-up control (Figure 6: Step S13). In tracking control, the movable part 393 moves the line of sight of the camera body 391 so that the hook 28 approaches the center of the imaging range. For example, the center C (central center) of the frame W in the captured image is considered to be the center of the hook 28, and the movable part 393 is controlled so that the center C is located at the center of the captured image. More specifically, the position of the center C of the frame W within the captured image is determined, and the amount of vertical and horizontal displacement relative to the center of the captured image is calculated. Then, according to the amount of displacement in each direction, the line of sight of the camera body 391 is tilted around two axes by the movable part 393 to adjust so that the center C of the frame W coincides with the center of the captured image. Furthermore, the amount of misalignment between the center C of the frame W and the center of the captured image, and the tilt angle of the two axes by the movable part 393, vary depending on the display magnification of the captured image. Therefore, the amount of movement of the movable part 393 is determined taking into account the display magnification of the captured image. Furthermore, the method for aligning the hook 28 to the center of the captured image is not limited to the above; for example, it may be adjusted to align a specific point within the image of a particular area or within frame W to the center of the captured image. Then, the imaging control is terminated. The above imaging control is executed repeatedly in short periods.

[0049] On the other hand, if it is determined in step S9 that the "always-on tracking setting" is not set, the controller 31 determines whether the "scaling tracking setting" is set (Figure 7: step S15). If the "scaling tracking setting" is enabled, the controller 31 determines whether or not there is an input from the input unit 331 to the camera body 391 for scaling the captured image (Figure 7: Step S17).

[0050] The controller 31 waits for input if there is no input for scaling the captured image, and if input is received, it controls the camera body 391 to scale the captured image and displays the scaled image on the display device 332 (Figure 7: Step S19). Then, the process proceeds to step S13, where the aforementioned tracking control is executed, and the imaging control is completed.

[0051] On the other hand, if it is determined in step S15 that the "Expand / Retract Follow Setting" is not set, the controller 31 determines whether or not the "Swivel Non-Follow Setting" is set (Figure 7: Step S21). Then, if the "non-following setting during rotation" is set, the controller 31 determines whether or not there is an input for rotation of the upper rotating body 22 by the operating lever 37 (Figure 7: Step S23).

[0052] If there is no input for rotation, the controller 31 proceeds to step S11, executes the aforementioned automatic image scaling process, and then performs tracking control, at which point the imaging control ends. Furthermore, when a rotation operation input is received, the controller 31 determines whether the rotation movement of the upper rotating body 22 has finished (Figure 7: step S25). The controller then repeats the above determination until the rotation movement is finished, waiting for the rotation movement to complete. Once the rotation movement is finished, the process proceeds to step S11, where the aforementioned automatic image scaling process is executed, and then tracking control is performed, ending the imaging control. In other words, with the "non-following during turning" setting, follow control is not performed from the start to the end of the turning motion.

[0053] On the other hand, if it is determined in step S21 that the "non-follow setting during turning" is not set, the controller 31 determines whether or not the "follow setting during elevation changes" is set (Figure 7: step S27). Then, if the "tracking during luffing" setting is enabled, the controller 31 determines whether or not there is an input from the operating lever 37 to control the luffing motion of the tower boom 24 or tower jib 25 (Figure 7: Step S29).

[0054] The controller 31 waits for input if there is no input for the elevation movement. If input is received, it proceeds to step S11 in accordance with the elevation movement, executes the aforementioned automatic image scaling process, and then performs tracking control to complete the imaging control.

[0055] On the other hand, if it is determined in step S27 that the "tracking setting during elevation" is not set, the controller 31 determines whether or not the "tracking setting during hook elevation" is set (Figure 7: step S31). Then, if the "hook lifting / lowering follow setting" is set, the controller 31 determines whether or not there is an input for lifting or lowering the hook using the operating lever 37 (Figure 7: Step S33).

[0056] The controller 31 waits for input if there is no input for the hook lifting / lowering operation. If input is received, it proceeds to step S11 in accordance with the hook lifting / lowering operation, executes the aforementioned automatic image scaling process, and then performs tracking control to complete the imaging control.

[0057] [Technical Effects of Embodiments of the Invention] At the crane terminal 30 of the crane 20 described above, the controller 31 performs tracking control to move the line of sight of the camera body 391 so that the hook 28, which is a specific part, approaches the center of the imaging range. This allows for monitoring of the entire area around the hook 28, enabling better surveillance. Furthermore, while images captured by a camera may exhibit distortion due to optical causes at positions offset from the center of the imaging range, the hook 28 is positioned towards the center of the image, enabling monitoring with high-quality images. Furthermore, with the tracking control described above, if the operator wants to monitor the hook 28 while operating the crane 20, the operator does not need to interrupt the crane operation to track the hook 28, and can immediately respond to operations such as avoiding contact with the building structure or people, thereby maintaining good operability.

[0058] Furthermore, when displaying the captured image of the hook 28, the controller 31 displays a frame W surrounding the hook 28, and in tracking control, controls the movable part 393 so that the center C of the frame W becomes the center of the captured image. Therefore, the center of the hook 28 can be easily and quickly determined, enabling smooth tracking control. Furthermore, the display of frame W allows for quick recognition of the location of hook 28 within the captured image, enabling better monitoring.

[0059] Furthermore, the controller 31 can perform a "scaling tracking setting" that controls the image as it is scaled up or down. This enables tracking control when an operator is actively trying to focus on the captured image, resulting in better monitoring. Furthermore, if the captured image is enlarged without tracking control, the display area on the screen narrows, making it easier for the hook 28 to move out of the display area. However, with tracking control, it becomes less likely for the hook to move out of the display area, enabling better monitoring. Furthermore, if no scaling operation is performed, i.e., if the captured image is not being viewed, tracking control can be disabled, thereby reducing the processing load.

[0060] Furthermore, in the automatic image scaling process, the controller 31 controls the camera body 391 to expand or contract the imaging range so that the range of the hook 28 (area of ​​frame W) relative to the imaging range becomes a predetermined ratio. As a result, the hook 28 is always displayed at a constant size regardless of the movement of the crane 20, allowing for stable visibility of the hook 28 and its surroundings, and enabling better monitoring.

[0061] Furthermore, since the camera 39 is installed on the tower jib 25 of the front attachment 23, it is positioned appropriately for monitoring specific areas of high importance (in this embodiment, the hook 28), enabling better monitoring. Furthermore, the camera 39 is installed in a location where its relative position to the hook 28 changes, and it moves in conjunction with the operation of the crane 20 during work. However, tracking control reduces the impact of the camera 39's movement, making monitoring possible.

[0062] Furthermore, the controller 31 has defined a "non-following during rotation" setting as a condition for executing follow-up control, which means that follow-up control will not be performed while the upper slewing body 22 of the crane 20 is rotating. This makes it possible to address the requirement to avoid monitoring based on images captured by follow-up control on the hook 28 when the sway becomes large due to the rotation of the upper slewing body 22, when the "non-following during rotation" setting is selected.

[0063] Furthermore, the controller 31 defines a "follow-up setting during luffing" as a condition for executing follow-up control, which executes follow-up control when the tower boom 24 or tower jib 25 is luffing or rotating. This makes it possible to monitor the hook 28, which swings significantly during luffing and rotating, effectively when the "follow-up setting during luffing" is selected.

[0064] Furthermore, the camera 39 has a grid 394 as a reference member positioned in front of the imaging direction. Therefore, the image of the grid 394 captured together with the hook 28 functions as a vibration display unit that displays the magnitude of the hook's vibration in a recognizable way. By comparing the width of one grid cell with the hook 28, the magnitude of the vibration occurring in the hook 28 can be visually recognized, enabling effective monitoring of the hook 28.

[0065] Furthermore, the controller 31 defines multiple execution conditions for follow control, such as "always follow setting," "follow setting during expansion and contraction," "non-follow setting during rotation," "follow setting during elevation and lowering," and "follow setting during hook elevation and lowering," and these can be selected by the input unit 331. Therefore, tracking control can be performed under appropriate conditions according to the status of the crane 20, and the crane 20 can be monitored effectively in response to a variety of situations.

[0066] [others] The details shown in the embodiments of the invention described above can be modified as appropriate without departing from the spirit of the invention.

[0067] For example, while the controller 31 has set "non-following during turning" as an execution condition for follow control, it may also add "non-following after turning" as an execution condition. In the "non-following after rotation setting," follow control is performed while the upper rotating body 22 is rotating, but the follow control is stopped immediately after the rotation ends. In this case, the system does not follow the sway caused by the tower boom 24 and tower jib 25 stopping when the rotation of the upper rotating body 22 ends. This allows monitoring of the sway of the hook 28 when it stops directly. Follow control can be restarted after a predetermined time has elapsed using a timer, or it can be restarted at the start of the next rotation operation.

[0068] Furthermore, although the above embodiment shows an example where only one execution condition for follow-up control can be selected, it is also possible to combine multiple execution conditions as long as the setting conditions do not contradict each other.

[0069] Furthermore, in the above embodiment, the display image of the grid 394 captured by the camera 39 was used as an example of a display unit for the magnitude of the swing of the hook 28, but the embodiment is not limited to this. For example, the grid image may be superimposed on the captured image using software. In that case, it is preferable to read the imaging magnification of the camera body 391 and change the display of the grid to a size corresponding to the imaging magnification. Alternatively, a numerical value indicating the magnitude of the swing of the hook 28 may be displayed as a swing indicator, either along with or in place of the image of the grid 394.

[0070] Furthermore, the cameras mounted on the crane 20 include not only so-called video cameras, but also any imaging means capable of capturing images, such as stereo cameras.

[0071] Furthermore, in the above embodiment, the range of the captured image displayed by the display device 332 is shown to be expandable and contractible by the zoom function of the camera body 391, as shown in Figures 4 and 5. When the zoom function described above allows the enlargement or reduction of the captured image to be arbitrarily controlled from the input unit 331, the controller 31 may perform display control, as shown in Figure 8, by dividing the display screen of the display device 332 into two sections and displaying the captured images before and after the change in enlargement or reduction side by side. Alternatively, the two captured images may be displayed within a portion of the display screen of the display device 332, rather than across the entire screen. Furthermore, the number of captured images displayed on the display screen of the display device 332 is not limited to two, but may be increased. In that case, it is possible to display captured images of each size that have been scaled up or down by multiple inputs from the input unit 331, or it is possible to display an captured image of the scaled size, the original captured image, and an captured image of a size between these two captured images, all based on a single input from the input unit 331. Furthermore, the number of captured images displayed on the above display screen may be arbitrarily set from the input unit 331. In this way, by displaying multiple captured images before and after scaling, it becomes possible to grasp the detailed situation of hook 28 and the surrounding area over a wide area, enabling more effective monitoring.

[0072] Furthermore, in the above embodiment, the hook 28 was given as an example of a specific part of the crane 20 to be monitored, but the embodiment is not limited to this. As shown in Figure 9, the configuration at the rear end of the crane 20 can be configured to monitor, for example, the counterweight 226, in order to ensure the rotational area is secured and to avoid interference with surrounding people H or objects. In that case, it is preferable to position the camera 39 in a location that allows imaging of the counterweight 226 from above. For example, it may be attached as a working part of the crane 20 in a suspended state from the upper end of the boom spreader 228. In this case, since the boom spreader 228 performs luffing and rotating motion relative to the upper slewing body 22, it corresponds to a part whose relative position changes with respect to the counterweight 226, which is a specific part. Thus, tracking control is particularly effective when the camera 39 is positioned so that it can move relative to the counterweight 226, which is the object being monitored, due to the crane's lifting operations. Here, "lifting operations" refers to operations such as raising and lowering the boom or jib, slewing, raising and lowering the hook, and driving the vehicle (driving when no load is suspended, for example, driving to move to a location where a load is suspended).

[0073] Figure 10 shows an example of a display screen of an image captured by the camera 39 of the counterweight 226. In the case of the aforementioned hook 28, the center C of the hook 28, which is aligned to the center of the captured image, was set as the centroid (more precisely, the center of the frame W) during tracking control. In contrast, in the case of the counterweight 226, the center C is set to the left-right center position of the rear end of the counterweight, and this center C is aligned to the center of the captured image. In other words, when the boom spreader 228 of the crane 20 performs a swinging motion, the controller 31 that performs tracking control controls the movable part 393 so that the center C set in the counterweight 226 is always located in the center of the captured image. This makes it possible to properly monitor the surroundings of the counterweight 226.

[0074] Furthermore, while the monitoring device in the above-described embodiment uses a tower crane as an example of a crane, it is not limited to this and can be applied to all types of cranes, including mobile cranes such as crawler cranes, wheel cranes, and truck cranes, as well as port cranes, overhead cranes, gantry cranes, unloaders, and fixed cranes. Furthermore, the present invention is applicable not only to cranes equipped with hooks, but also to cranes that suspend attachments such as magnets and earth drill buckets. [Explanation of symbols]

[0075] 20 Cranes 21 Lower running body 22 Upper rotating body 221 Swivel Frame 226 Counterweight (Specific part) 228 Boom spreader (operating part) 23 Front attachment (moving part) 24 Tower Boom 25 Tower Jib 26 Tower Strut 28. Lifting hook (hook, specific part) 30 Crane terminals 31. Controller (monitoring device) 331 Input section 332 Display device 39. Cameras (surveillance devices) 391 Camera body 392 Cover 393 Moving parts 394 Grid (reference member, vibration indicator) C center H people W frame

Claims

1. A crane monitoring device having a camera for monitoring a specific part of a crane, The line of sight of the camera is moved so that the specific part approaches the center of the imaging range. Crane monitoring equipment.

2. the camera is capable of expanding and contracting the imaging range, The line of sight of the camera is moved so that the specific part approaches the center of the imaging range at least when enlarged or reduced. The crane monitoring device according to claim 1.

3. The imaging range is expanded or reduced so that the range of the specific part relative to the imaging range is at a specified ratio. The crane monitoring device according to claim 2.

4. The camera is installed at a location where the relative position with respect to the specific location changes. The crane monitoring device according to any one of claims 1 to 3.

5. the specific portion is a hook, During or at the end of rotation of the upper rotating body of the crane, the line of sight of the camera is not moved so that the specific part approaches the center of the imaging range. The crane monitoring device according to claim 4.

6. the specific portion is a hook, When the crane is being raised or lowered or the hook is being lifted or lowered, the line of sight of the camera is moved so that the specific part approaches the center of the imaging range. The crane monitoring device according to claim 4 or 5.

7. the specific portion is a hook, A swing display unit is provided to recognizably display the magnitude of swing of the hook. A crane monitoring device according to any one of claims 1 to 6.

8. a display unit for displaying a captured image; a reference member disposed in front of the camera in the imaging direction; The crane monitoring device according to claim 7, wherein an image including the hook and the reference member captured by the camera is displayed on the display unit as an image that allows the magnitude of swing of the hook to be recognized.

9. a display unit for displaying a captured image; the camera is capable of expanding and contracting the imaging range, A plurality of screens having different enlargement / reduction ratios of the imaging range are displayed on the display unit. A crane monitoring device according to any one of claims 1 to 8.

10. a plurality of conditions for moving the line of sight of the camera so that the specific portion approaches the center of the imaging range; The plurality of conditions can be selected. A crane monitoring device according to any one of claims 1 to 9.

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