JP7825971B2 - Crane anti-sway device and crane equipped with same - Google Patents

Description

The present invention relates to a crane sway prevention device and a crane equipped with the same.

Traditionally, mobile cranes have been known that include a lower running body, an upper rotating body supported on the lower running body so that it can rotate around a vertically extending central axis of rotation, and a hoisting body such as a boom or jib. The hoisting body is attached to the upper rotating body so that it can rotate in the hoisting direction around a horizontal central axis of rotation. A hook is attached to a load rope hanging down from the tip of the hoisting body, and the load is lifted by connecting it to the hook.

Patent Document 1 discloses a technology for controlling the rotation of an upper rotating body of a crane with a boom when the load is swinging (swinging during rotation) so that the tip of the boom is moved to a position vertically above the load. As the tip of the boom moves to follow the load, the swing of the load eventually attenuates.

Japanese Patent Application Laid-Open No. 2008-74579

The technology described in Patent Document 1 requires the crane to rotate to prevent the suspended load from swaying, making it difficult to prevent swaying in limited spaces where rotation is not possible.

The present invention was made in consideration of the above problems, and its purpose is to provide a crane and a sway prevention device that can dampen the sway of a suspended load without actively moving the suspended load horizontally.

A crane sway prevention device according to one aspect of the present invention is used in a crane. The crane has a crane body, a rope suspended from a predetermined fulcrum and connected to a suspended load, and a lifting unit capable of receiving command signals and raising or lowering the suspended load via the rope in response to the command signals. The sway prevention device is capable of executing sway prevention control to suppress sway of the suspended load. The sway prevention device has a control unit. The control unit determines the sway direction of the suspended load, and if the sway direction is a return direction approaching a reference line passing through the fulcrum and extending vertically, inputs the command signal to the lifting unit to lower the suspended load so that a downward acceleration is applied to the suspended load. If the sway direction is an away direction away from the reference line, inputs the command signal to the lifting unit to raise the suspended load so that an upward acceleration is applied to the suspended load.

With this configuration, the load is raised or lowered so that a downward acceleration is applied to the load when it is moving toward the reference line, and an upward acceleration is applied to the load when it is moving away from the reference line, thereby reducing the kinetic energy of the load and damping the sway of the load. Therefore, compared to conventional methods of damping the sway of the load by rotating the crane, the sway can be damped even in limited spaces without actively moving the load horizontally.

In the above configuration, it is desirable that the lifting unit includes a load winch that can raise the load by winding in the rope and lower the load by letting out the rope, and that the control unit inputs the command signal to the lifting unit so that the load winch lets out the rope when the swing direction is the return direction, and the load winch winds up the rope when the swing direction is the away direction.

With this configuration, the load is raised and lowered using a load winch, which makes it difficult for horizontal movement forces to act on the load, and it is possible to efficiently apply vertical acceleration to the load while damping the sway of the load.

In the above configuration, it is desirable that the crane further includes a hoisting body that includes the fulcrum and is supported on the crane body so that it can be raised or lowered, the lifting unit includes a hoisting device that can rotate the hoisting body in the hoisting direction, and the control unit inputs the command signal to the lifting unit so that when the swing direction is the return direction, the hoisting device rotates the hoisting body in the lowering direction, and when the swing direction is the away direction, the hoisting device rotates the hoisting body in the upright direction.

With this configuration, the load is raised and lowered by the raising and lowering action of the lifting body, so the sway of the load can be damped even if there are restrictions on the rope winding and unwinding operations using the load winch at the work site.

The above configuration preferably further comprises a derrick angle detection unit capable of detecting the derrick angle of the derrick body, and a load position detection unit capable of detecting the relative position of the load with respect to the reference line in the fore-and-aft direction of the crane body, and the control unit preferably inputs the command signal to the lifting unit when the derrick angle detected by the derrick angle detection unit is greater than a preset threshold and the relative position of the load detected by the load position detection unit is behind the reference line, but suspends input of the command signal to the lifting unit when the relative position of the load is ahead of the reference line.

With this configuration, when the elevation angle of the elevation body is relatively large, anti-sway control is performed only when the suspended load is located behind the reference line, thereby damping the sway while preventing it from increasing.

In the above configuration, it is desirable that when the elevation angle detected by the elevation angle detection unit is smaller than the threshold value, the control unit inputs the command signal to the lifting unit regardless of the relative position of the suspended load detected by the suspended load position detection unit.

With this configuration, when the elevation angle of the elevation body is relatively small, the elevation movement of the elevation body is less likely to worsen the sway of the suspended load, making it possible to actively perform anti-sway control regardless of the relative position of the suspended load with respect to the reference line.

In the above configuration, it is desirable to further include a load height detection unit capable of detecting the height of the load relative to the ground when the load is stationary on the reference line, and for the control unit to input the command signal to the lifting unit so as to prevent the height of the load detected by the load height detection unit from becoming lower than the initial height, which is the height of the load before the anti-sway control is executed.

With this configuration, even if there is an obstacle below the suspended load when anti-sway control is performed, contact between the suspended load and the obstacle can be prevented.

In the above configuration, if the swing of the suspended load is within a preset tolerance range and the height of the suspended load differs from the initial height, it is desirable that the control unit input the command signal to the lifting unit so that the height of the suspended load returns to the initial height.

This configuration allows the swing of the suspended load to be dampened and the load to be returned to its initial height, allowing for quick transition to the next task.

In the above configuration, it is desirable that the control unit calculates the swing period of the suspended load and inputs the command signal to the lifting unit so as to adjust the magnitude of the acceleration applied to the suspended load in accordance with the calculated period.

With this configuration, the time required to dampen the sway can be shortened by adjusting the acceleration applied to the load according to the sway period of the load. In particular, when the sway period of the load is long, there is ample time to perform sway prevention control, so by setting a large acceleration to be applied to the load, the damping of the sway of the load can be accelerated. Furthermore, when the sway period of the load is short, by reducing the acceleration to be applied to the load, it is possible to prevent the load from reaching the reference line or the highest point of the sway during sway prevention control, and erroneously applying acceleration in the opposite direction to the load.

The present invention also provides a crane. The crane includes a crane body, a rope hanging from a predetermined fulcrum and connected to a suspended load, a lifting unit capable of receiving command signals and raising or lowering the suspended load in response to the command signals, and the above-described crane anti-sway device capable of executing anti-sway control to suppress sway of the suspended load.

With this configuration, compared to conventional methods of damping the sway of a suspended load by rotating the crane, the sway can be damped even in limited spaces without actively moving the suspended load horizontally.

The present invention provides a crane sway prevention device and a crane that can dampen the sway of a suspended load without actively moving the suspended load horizontally.

FIG. 1 is a side view of a crane according to a first embodiment of the present invention. FIG. 1 is a block diagram of a crane according to a first embodiment of the present invention. FIG. 1 is a schematic plan view of a crane according to a first embodiment of the present invention. 1 is a schematic side view of a crane according to a first embodiment of the present invention. FIG. 4 is a flowchart of swing prevention control for a crane according to the first embodiment of the present invention. FIG. 10 is a schematic side view for explaining anti-sway control of a suspended load. FIG. 10 is a schematic side view for explaining anti-sway control of a suspended load. FIG. 10 is a schematic side view of a crane according to a second embodiment of the present invention. 10 is a flowchart of swing prevention control for a crane according to a second embodiment of the present invention. FIG. 10 is a schematic side view for explaining anti-sway control of a suspended load. FIG. 10 is a schematic side view for explaining anti-sway control of a suspended load. FIG. 10 is a schematic side view for explaining anti-sway control of a suspended load. FIG. 10 is a schematic side view for explaining anti-sway control of a suspended load.

First Embodiment
A first embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a side view of a crane 10 according to this embodiment. Note that although Fig. 1 indicates directions such as "up,""down,""front," and "rear," these directions are shown for the sake of convenience in explaining the structure of the crane 10 according to this embodiment, and do not limit the direction of movement or the manner of use of the crane according to the present invention.

The crane 10 comprises a running body 14, an upper rotating body 12 (crane body) supported on the running body 14 so as to be rotatable around a central axis of rotation extending in the vertical direction, and a boom 16 (hoisting body) and mast 20 supported on the upper rotating body 12 so as to be able to be raised and lowered. A counterweight 13 is mounted on the rear of the upper rotating body 12 to adjust the balance of the crane 10. A cab 15 is also provided at the front end of the upper rotating body 12. The cab 15 corresponds to the driver's seat of the crane 10.

The boom 16 shown in FIG. 1 is a so-called lattice type, consisting of a lower boom 16A (the base end of the hoisting unit), one or more (three in the illustrated example) intermediate booms 16B, 16C, and 16D, and an upper boom 16E (the tip end of the hoisting unit opposite the base end of the hoisting unit). Specifically, the lower boom 16A is supported at the front of the upper rotating unit 12 so that it can rotate in the hoisting direction around a horizontal central axis of rotation (first central axis of rotation). The intermediate booms 16B, 16C, and 16D are detachably attached to the tip end of the lower boom 16A, in that order. The upper boom 16E is detachably attached to the tip end of the intermediate boom 16D. The lower boom 16A is rotatably supported on the upper rotating unit 12 by a boom foot 16S provided at its lower end.

The boom 16 also has idler sheaves 34S and 36S. The idler sheaves 34S and 36S are each rotatably supported on the rear side of the base end of the lower boom 16A.

However, the present invention does not limit the specific structure of the boom. For example, the boom may not have an intermediate member, or may have a different number of intermediate members than those described above. Furthermore, the boom may be constructed from a single member. The boom may also be a telescopic boom that can be extended and retracted.

The mast 20 has a base end and a pivot end, and the base end is pivotally connected to the upper rotating body 12. The pivot axis of the mast 20 is parallel to the pivot axis of the boom 16 and is located immediately rearward of the pivot axis of the boom 16. In other words, the mast 20 can pivot in the same direction as the boom 16's elevation.

The crane 10 also includes a pair of left and right backstops 23 and a pair of left and right boom guy lines 24.

A pair of left and right backstops 23 are provided on both the left and right sides of the lower boom 16A of the boom 16. These backstops 23 abut against the center of the upper rotating body 12 in the fore-and-aft direction when the boom 16 reaches the upright position shown in Figure 1. This abutment prevents the boom 16 from being blown backward by strong winds, etc.

A pair of left and right boom guy lines 24 connect the rotating end of the mast 20 to the tip of the boom 16. This connection coordinates the rotation of the mast 20 and the rotation of the boom 16.

The crane 10 also includes various winches. Specifically, the crane 10 includes a boom hoist winch 30 (hoisting device) for raising and lowering the boom 16, a main hoisting winch 34 (load winch) for hoisting and lowering the load, and an auxiliary hoisting winch 36. The crane 10 also includes a boom hoist rope 38, a main hoisting rope 50 (rope) that hangs down from the upper boom 16E (tip of the boom 16) and connects to the load, and an auxiliary hoisting rope 60. In the crane 10 according to this embodiment, the main hoisting winch 34 and auxiliary hoisting winch 36 are installed near the base end of the boom 16. The boom hoist winch 30 is installed on the upper rotating body 12. The locations of these winches 30, 32, 34, and 36 are not limited to those described above.

The boom hoist winch 30 winds and pays out the boom hoist rope 38. The boom hoist rope 38 is routed so that this winding and paying out causes the mast 20 to rotate. Specifically, sheave blocks 40, 42, each with multiple sheaves arranged in the width direction, are provided at the rotating end of the mast 20 and the rear end of the upper rotating body 12, and the boom hoist rope 38 pulled out from the boom hoist winch 30 is stretched between the sheave blocks 40, 42. Therefore, when the boom hoist winch 30 winds and pays out the boom hoist rope 38, the distance between the two sheave blocks 40, 42 changes, causing the mast 20 and, in turn, the boom 16 to rotate in the hoisting direction.

The main hoisting winch 34 hoists and lowers the load using the main hoisting rope 50. The main hoisting rope 50 hangs down from the upper boom 16E of the boom 16 and is connected to the load. A main hoisting guide sheave 54 is also disposed on the upper boom 16E, and a main hoisting sheave block is provided adjacent to the main hoisting guide sheave 54, with multiple main hoisting point sheaves 56 arranged in the width direction. The main hoisting rope 50 pulled out from the main hoisting winch 34 is hung in turn around the idler sheave 34S and the main hoisting guide sheave 54, and is then stretched between the main hoisting point sheave 56 of the sheave block and the sheave 58 of the sheave block provided on the main load hook 57. Therefore, when the main hoisting winch 34 winds or unwinds the main hoisting rope 50, the distance between the two sheaves 56, 58 changes, causing the main hook 57 connected to the main hoisting rope 50 hanging down from the tip of the boom 16 to be hoisted up or down. As a result, the load can be hoisted up or down.

Similarly, the auxiliary winch 36 hoists and lowers the load using the auxiliary hoisting rope 60. For this auxiliary hoisting, an auxiliary hoisting guide sheave 64 is rotatably mounted coaxially with the main hoisting guide sheave 54, and an auxiliary hoisting point sheave (not shown) is rotatably mounted adjacent to the auxiliary hoisting guide sheave 64. The auxiliary hoisting rope 60 pulled out from the auxiliary hoisting winch 36 is hooked in turn around the idler sheave 36S and the auxiliary hoisting guide sheave 64, and then suspended from the auxiliary hoisting point sheave. Therefore, when the auxiliary hoisting winch 36 winds or unwinds the auxiliary hoisting rope 60, the auxiliary hook for the load (not shown), which is connected to the end of the auxiliary hoisting rope 60, is hoisted or lowered.

Figure 2 is a block diagram of the crane 10 according to this embodiment. Figures 3 and 4 are schematic plan and side views of the crane 10 according to this embodiment. Referring to Figure 2, the crane 10 further includes an operation unit 70, an input unit 71, a camera 72 (load position detection unit), a boom angle meter 73 (boom hoisting angle detection unit, load height detection unit), a rope length detection unit 74 (load height detection unit), a boom hoisting drive unit 80, a winch drive unit 81, a swing drive unit 82, and a control unit 90.

The operation unit 70 is, for example, located inside the cab 15 and accepts operations by the operator to drive each component of the crane 10. The operation unit 70 includes a hoisting operation unit 70A, a winch operation unit 70B, and a swing operation unit 70C. Note that if the crane 10 is remotely operated, the operation unit 70 may be located in a location different from the crane 10.

The hoisting operation unit 70A accepts operations to raise or lower the boom 16 using the boom hoist drive unit 80. The hoisting operation unit 70A is switchable between a hoisting position for raising or lowering the boom 16 and a neutral position for stopping the hoisting of the boom 16. For example, the hoisting operation unit 70A is a lever; tilting the lever in one direction rotates the boom 16 in the upright direction, tilting the lever in the opposite direction rotates the boom 16 in the lowered direction, and placing the lever in the neutral position stops the hoisting operation of the boom 16. A signal corresponding to the direction and amount of operation of the lever is input to the control unit 90.

The winch operating unit 70B accepts operations to raise and lower the suspended load using the winch drive unit 81. The winch operating unit 70B is switchable between a lifting position for lifting and lowering the suspended load and a neutral position for stopping the lifting and lowering of the suspended load. For example, the winch operating unit 70B is a lever; tilting the lever in one direction rotates the main hoisting winch 34 so that the suspended load rises; tilting the lever in the other direction opposite to the one direction rotates the main hoisting winch 34 so that the suspended load falls; and placing the lever in the neutral position stops the lifting and lowering operation of the suspended load (the rotation of the main hoisting winch 34). A signal corresponding to the direction and amount of operation of the lever is input to the control unit 90.

The rotation control unit 70C accepts operations to rotate the upper rotating body 12 using the rotation drive unit 82. The rotation control unit 70C is switchable between rotation positions for rotating the upper rotating body 12 in a first rotation direction and a second rotation direction opposite to the first rotation direction, and a neutral position for stopping the rotation of the upper rotating body 12. For example, the rotation control unit 70C is a lever; tilting the lever in one direction rotates the upper rotating body 12 in the first rotation direction; tilting the lever in another direction opposite to the first direction rotates the upper rotating body 12 in the second rotation direction; and placing the lever in the neutral position stops the rotation of the upper rotating body 12. A signal corresponding to the direction and amount of operation of the lever is input to the control unit 90.

The input unit 71 is located, for example, inside the cab 15 and accepts various input information about the crane 10 from the operator. The input unit 71 includes an execution switch for starting the execution of the anti-sway control described below.

As shown in Figure 4, the camera 72 is positioned at the upper end of the boom 16, with its imaging range facing downward. The camera 72 is capable of detecting the relative position of the load R with respect to the reference line CL (Figure 4). In this embodiment, the image captured by the camera 72 is input to the control unit 90, which acquires information such as the position of the load R. At this time, as shown in Figure 4, a marker 57M is attached to the main hook 57 in advance, allowing the camera 72 to track the position of the marker 57M and accurately detect (photograph) the position of the load R.

The boom angle meter 73 is located at the boom foot 16S and detects the boom hoist angle α (Figure 4) of the boom 16. The boom hoist angle α is the angle between the center line extending in the longitudinal direction of the boom 16 and a horizontal line extending forward from the boom foot 16S. Note that the boom hoist angle α may also be detected based on other angles.

The rope length detection unit 74 detects the rope length _L2 ( FIG. 4 ) of the main hoisting rope 50 hanging down from the upper end of the boom 16. Note that in FIG. 4 , rope length _L2 is shown as the length from the main hoisting point sheave 56 (the swing fulcrum of the main hoisting rope 50) at the upper end of the boom 16 to the center of gravity of the suspended load R, but it may also be the length from the main hoisting point sheave 56 to the main hook 57 (sheave 58), for example. The rope length detection unit 74 includes a rotation amount detection unit capable of detecting the amount of rotation of the main hoisting winch 34, and a winding layer detection unit that detects the number of winding layers of the main hoisting rope 50 on the outer circumferential surface of the main hoisting winch 34. The rope length detection unit 74 calculates and outputs the distance from the winch diameter of the main hoisting winch 34, the amount of winch rotation detected by the rotation amount detection unit, the amount of main hoisting rope 50 let out from the main hoisting winch 34 estimated from the wound layers of the main hoisting rope 50 detected by the wound layer detection unit, and the number of loops of the main hoisting rope 50 between the main hoisting point sheave 56 and the sheave blocks of the sheave 58. The rope length _L2 may also be calculated by other methods.

The length _L1 of the boom 16, the rope length _L2 detected by the rope length detection unit 74, and the boom hoisting angle α detected by the boom angle meter 73 are also used to calculate the height H of the load R (main hook 57) relative to the ground. The height H is the height when it is assumed that the load R is stationary on the reference line CL. The reference for the height H may be something other than the ground.

The boom hoisting drive unit 80 in Figure 2 includes the boom hoist winch 30 described above, and is capable of generating a driving force to rotate the boom hoist winch 30 and rotate the boom 16 about the central axis of rotation. The boom hoisting drive unit 80 includes a hydraulic motor that receives a supply of hydraulic oil to rotate the boom hoist winch 30.

The winch drive unit 81 includes the aforementioned main hoisting winch 34 and generates a driving force to rotate the main hoisting winch 34. By using the main hoisting winch 34 to wind and unwind the main hoisting rope 50, the load can be raised and lowered relative to the ground. The same applies to the auxiliary hoisting winch 36. The winch drive unit 81 includes a hydraulic motor that receives a supply of hydraulic oil to rotate the main hoisting winch 34 and auxiliary hoisting winch 36.

The boom hoisting drive unit 80 and winch drive unit 81 constitute the lifting unit of the present invention. The lifting unit is capable of receiving command signals and raising and lowering the load R via a rope in accordance with the command signals.

The slewing drive unit 82 generates a driving force capable of rotating the upper slewing body 12 in each of the first and second slewing directions around the central slewing axis. The slewing drive unit 82 includes a hydraulic motor that receives a supply of hydraulic oil to rotate the upper slewing body 12.

The control unit 90 is composed of a CPU (Central Processing Unit), ROM (Read Only Memory) that stores the control program, and RAM (Random Access Memory) used as the CPU's work area. The control unit 90 functions as a drive control unit 901, a load swing control unit 902, and a memory unit 903 by the CPU executing the control program stored in the ROM. These functional units do not have physical entities, but correspond to units of function executed by the control program. Note that all or part of the control unit 90 is not limited to being located within the crane 10; if the crane 10 is remotely controlled, it may be located in a location separate from the crane 10. The control program may be transmitted from a remote server (management device) or cloud to the control unit 90 within the crane 10 and executed therein, or the control program may be executed on the server or cloud and its commands transmitted to the crane 10. The control unit 90, together with the aforementioned camera 72, boom angle meter 73, and rope length detection unit 74, constitutes the anti-sway device 100 (Figure 2) of the present invention. The anti-sway device 100 is capable of performing anti-sway control to suppress sway of the suspended load R, with the tip of the boom 16 as the fulcrum.

Next, we will explain each functional unit of the control unit 90. The drive control unit 901 inputs command signals corresponding to the direction and amount of operation received by the boom hoisting operation unit 70A, winch operation unit 70B, and swing operation unit 70C to the boom hoisting drive unit 80, winch drive unit 81, and swing drive unit 82, respectively, to drive each drive unit.

The load sway control unit 902 is capable of suppressing sway of the load R, which is a phenomenon in which the load R connected to the main hoisting rope 50 sways around the main hoisting point sheave 56 of the upper boom 16E as a fulcrum, after the upper rotating body 12 has stopped rotating (anti-sway control). Note that sway of the load R also includes sway caused by wind or other factors when the crane 10 is stationary. Furthermore, when the load sway control unit 902 performs anti-sway control, command signals for anti-sway control are input from the load sway control unit 902 to each drive unit, regardless of the direction and amount of operation received by the hoisting operation unit 70A, winch operation unit 70B, and swing operation unit 70C.

The storage unit 903 stores in advance various thresholds, parameters, and the like that are referenced in the normal drive control executed by the drive control unit 901 and the anti-sway control executed by the load sway control unit 902. As an example, the storage unit 903 stores in advance a boom length _L1 (FIG. 4) that is the length of the boom 16. Note that the operator may input the boom length _L1 via the input unit 71, and the storage unit 903 may store it.

The control unit 90, which has the functional units described above, controls the boom hoisting drive unit 80 or the winch drive unit 81 to perform anti-sway control of the load R. In particular, the control unit 90 determines whether the anti-sway control is permitted or prohibited, and also determines the sway direction of the load R. If the sway direction is a return direction approaching the reference line CL that passes through the main hoist guide sheave 54 (fulcrum) and extends vertically, the control unit 90 inputs the command signal to the boom hoisting drive unit 80 or the winch drive unit 81 to lower the load R so that a downward acceleration is applied to the load R. If the sway direction is a direction away from the reference line CL, the control unit 90 inputs the command signal to the boom hoisting drive unit 80 or the winch drive unit 81 to raise the load R so that an upward acceleration is applied to the load R. Furthermore, in the prohibited state, the control unit 90 suspends (suspends) the input of the command signal regardless of the sway direction of the load R. Here, the permitted state is a state in which the input of the command signal to the lifting unit (boom hoisting drive unit 80, winch drive unit 81) is permitted, and the prohibited state is a state in which the input of the command signal to the lifting unit is prohibited. As described above, if the anti-sway device 100 has a switch that executes anti-sway control, the control unit 90 determines that anti-sway control is permitted when the switch is turned on, and determines that anti-sway control is prohibited when the switch is turned off.

<On the equation of motion for anti-sway control>
In the present invention, when the load R is swaying, the kinetic energy included in the law of conservation of energy is reduced by accelerating the load R, thereby suppressing the vibration of the load R. As a method for accelerating the load R, the winding and unwinding operations of the main hoisting rope 50 and the raising and lowering operation of the boom 16 can be used.

Using the aforementioned boom length L ₁ , rope length L ₂ of the main hoisting rope 50, boom hoisting angle α, and swing angle θ of the load R ( FIG. 6 ), the equation of motion for the load angle in the radial direction of the load R can be expressed by the following Equation 1 by solving Lagrange's equation of motion.

Here, g is the gravitational acceleration. From the differential component of acceleration included in the last term of Equation 1, the apparent gravitational acceleration g _apr of the suspended load R can be expressed by the following Equation 2.

In other words, it can be seen that the apparent gravitational acceleration of the load R changes depending on, for example, the boom hoisting angle α and its angular acceleration. Furthermore, as will be described later, the apparent gravitational acceleration of the load R also changes depending on the winding and unwinding of the main hoisting rope 50.

Here, in order to suppress the sway of the load R due to the raising and lowering of the boom 16 and the winding and unwinding of the main hoisting rope 50, it is necessary to apply acceleration to the load R at an appropriate time. For this reason, it is desirable to adjust the input time (timing) of the acceleration by understanding the period of the load R. When the behavior of the load R is considered to be a simple pendulum, if the initial sway angle θ of the load R is _θ0 , the sway period T of the load R can be calculated by the following equation 3.

As described above, when the sway of the load R is adjusted by the raising and lowering operation of the boom 16, the apparent gravitational acceleration of the load R changes as shown in Equation 2. Therefore, by replacing the gravitational acceleration g in Equation 3 above with the gravitational acceleration g _apr in Equation 2, the sway period T can be calculated with high accuracy.

On the other hand, when the boom 16 hoisting angle α is maintained constant and the sway of the load R is suppressed by winding and unwinding the main hoisting rope 50, the differential component of the boom hoisting angle α in the equation of motion of Equation 1 described above becomes zero, and therefore the equation of motion of the load R can be expressed by Equation 4 below.

Furthermore, in the apparent gravitational acceleration of the load R (Equation 2), the differential component of the hoisting angle α is zero, while the acceleration due to winding and unwinding of the main hoisting rope 50 is added, so the apparent gravitational acceleration of the load R can be expressed as in the following Equation 5. Here, g _h is the acceleration brought about on the main hook 57 by winding and unwinding of the main hoisting rope 50. Note that because Equation 5 is the acceleration as seen from the load R, the direction of the acceleration g _h is opposite to the direction of the actual acceleration of the main hook 57.

In addition, since the suspended load R is constantly subjected to downward gravitational acceleration g, applying upward acceleration to the suspended load R means that the downward acceleration will decrease, and applying downward acceleration to the suspended load R means that the downward acceleration will increase.

<About the anti-sway control flow>
Next, the flow of sway prevention control of the suspended load R by the sway prevention device 100 according to this embodiment will be described. The following explanation will discuss how sway of the suspended load R is suppressed by winding and unwinding the main hoisting rope 50. As shown in FIGS. 3 and 4 , a vertical line passing through the upper end of the boom 16 (the main hoisting point sheave 56 in FIG. 1 , the fulcrum for the sway of the suspended load R) is defined as the reference line CL. Furthermore, with regard to the movement of the suspended load R, the direction rearward from the reference line CL, i.e., the horizontal direction toward the upper rotating body 12, is defined as the +X direction, and the horizontal direction forward from the reference line CL is defined as the -X direction. Furthermore, the direction toward the right from the reference line CL is defined as the +Y direction, and the direction toward the left from the reference line CL is defined as the -Y direction. Furthermore, the upward direction is defined as the +Z direction, and the downward direction is defined as the -Z direction.

Figure 5 is a flowchart of the swing anti-sway control of the crane 10 according to this embodiment. Figures 6 and 7 are schematic side views for explaining the swing anti-sway control of the suspended load R. Referring to Figure 5, when the operator turns on the swing anti-sway control execution switch included in the input unit 71 (Figure 2), the control unit 90 of the swing anti-sway device 100 starts the swing anti-sway control. At this time, even if the operator operates the operation unit 70, the swing anti-sway control is automatically executed regardless of the operation.

When the control unit 90 starts sway prevention control, it measures the sway of the suspended load R (step S1 in Figure 5). During this measurement, the camera 72 continuously captures images including the suspended load R, and this image information is input to the control unit 90. The load sway control unit 902 identifies the relative position of the suspended load R with respect to the reference line CL from the image information, and obtains information regarding the maximum amplitude (sway amount Q) and direction of the sway.

Next, the load sway control unit 902 compares the acquired sway amount Q of the suspended load R with a preset sway threshold QS (step S2). The sway threshold QS is pre-stored in the memory unit 903 as an absolute value of the allowable sway range. If the sway amount Q>QS (YES in step S2), the load sway control unit 902 determines that sway prevention of the suspended load R is necessary through sway prevention control. In this case, the load sway control unit 902 measures the height H of the suspended load R before control begins. The measured height H of the suspended load R is stored in the memory unit 903 as the initial height H0 (step S3).

Next, the load sway control unit 902 calculates the swing period T of the suspended load R using the aforementioned equation 3 (step S4). Furthermore, the load sway control unit 902 determines whether the suspended load R is moving toward the reference line CL based on the image information captured by the camera 72 (step S5). Here, as shown by arrow D61 in Figure 6, if the suspended load R is approaching the reference line CL while moving in the -X direction and the -Z direction (return direction) (YES in step S5), the load sway control unit 902 determines whether the current height H of the suspended load R is higher than the initial height H0 (step S6). Because H = H0 at the start of anti-sway control for the suspended load R (NO in step S6), the load sway control unit 902 maintains the height of the main hook 57 (height of the suspended load R) (step S11) and returns to step S5. In this case, steps S5, S6, and S11 are repeated until the load R is raised via the flow from step S12 onwards, which will be described later. On the other hand, if H0<H in step S6 (YES in step S6), the load swing control unit 902 calculates the current remaining time S (step S7). The remaining time S corresponds to the time until the load R, moving as indicated by arrow D61 in FIG. 6, reaches the reference line CL. Note that the remaining time S may be calculated from the period T of the load swing of the load R and the current position of the load R, or the time at which the load R will next reach the reference line CL may be calculated directly from the position and acceleration of the load R imaged by the camera 72.

In step S8, if the remaining time S is greater than the time threshold SA previously stored in the memory unit 903 (YES in step S8), the load swing control unit 902 inputs a command signal to the winch drive unit 81, causing the main hoisting winch 34 to pay out the main hoisting rope 50, thereby executing hook lowering as indicated by arrow D62 in Figure 6 (step S9). As a result, the tension in the main hoisting rope 50 temporarily decreases, and a downward acceleration is applied to the load R. As a result, a braking force acts on the load R moving toward the reference line CL, keeping it near the reference line CL. The time threshold SA is set based on whether it is possible to lower the main hook 57 before the load R reaches the reference line CL, taking into account factors such as the response time from when the command signal is input to the winch drive unit 81 until the main hoisting winch 34 actually begins to rotate in the payout direction. On the other hand, in step S8, if the remaining time S is less than or equal to the time threshold SA (NO in step S8), the load swing control unit 902 refrains from applying a braking force to the suspended load R moving in the direction of arrow D61 in Figure 6, maintains the height of the main hook 57 (step S10), and returns to step S1.

In the processing after step S5 in Figure 5, the flow when the load R is moving toward the reference line CL is the same as when the load R is moving toward the reference line CL while moving in the +X direction and the -Z direction (return direction), as shown by arrow D63 in Figure 6. In this case, if the remaining time S is greater than the time threshold SA in step S8 (YES in step S8), the load swing control unit 902 inputs a command signal to the winch drive unit 81, and the main hoisting winch 34 unwinds the main hoisting rope 50, thereby lowering the hook as shown by arrow D64 in Figure 6 (step S9). As a result, a braking force similar to that described above acts on the load R.

On the other hand, in step S5, as shown by arrow D71 in FIG. 7, if the load R is moving in the -X direction and the +Z direction (away direction) while moving away from the reference line CL (NO in step S5), the load swing control unit 902 calculates the remaining time S as in step S7 (step S12). If the remaining time S is greater than the time threshold value SB previously stored in the memory unit 903 (YES in step S13), the load swing control unit 902 inputs a command signal to the winch drive unit 81, causing the main hoisting winch 34 to reel in the main hoisting rope 50, thereby performing hook lifting as shown by arrow D72 in FIG. 7 (step S14). As a result, the tension in the main hoisting rope 50 temporarily increases, and an upward acceleration is applied to the load R. As a result, a braking force acts on the load R, which is moving away from the reference line CL, pulling it toward the reference line CL. Note that, like time threshold value SA, time threshold value SB is set based on whether it is possible to raise the main hook 57 before the load R reaches the highest point of swing, taking into consideration factors such as the response time from when a command signal is input to the winch drive unit 81 until the main hoisting winch 34 actually begins to rotate in the winding direction. Time threshold value SB may be the same value as time threshold value SA. On the other hand, in step S13, if the remaining time S is equal to or less than time threshold value SA (NO in step S13), the load swing control unit 902 refrains from applying a braking force to the load R moving in the direction of arrow D71 in FIG. 7, maintains the height of the main hook 57 (step S10), and returns to step S1.

In the processing after step S5 in FIG. 5, the flow when the load R is moving away from the reference line CL is the same as when the load R is moving in the +X direction and the +Z direction (away direction) while moving away from the reference line CL, as shown by arrow D73 in FIG. 7. In this case, if the remaining time S is greater than the time threshold SA in step S13 (YES in step S13), the load swing control unit 902 inputs a command signal to the winch drive unit 81, and the main hoisting winch 34 reels in the main hoisting rope 50, thereby performing hook lifting as shown by arrow D74 in FIG. 7 (step S14). As a result, a braking force similar to that described above acts on the load R.

As described above, the kinetic energy of a load R moving toward the reference line CL can be reduced by lowering the load R (main hook 57) via the main hoisting rope 50. Similarly, the kinetic energy of a load R moving away from the reference line CL can be reduced by raising the load R (main hook 57) via the main hoisting rope 50. The above-described raising and lowering of the load R is controlled to end each time before the load R reaches the reference line CL or the highest point in the swing.

Note that with reference to Figure 6, regarding the sway prevention control of the load R, at the highest point of its swing, the kinetic energy of the load R is zero, while the potential energy is at its maximum. When the load R moves toward the reference line CL as shown in Figure 6, the potential energy is converted into kinetic energy as the load R moves. At this time, if the load R is lowered via the main hoisting rope 50 as described above, the downward acceleration acting on the load R decreases, and as a result, the kinetic energy (speed) when it reaches the reference line CL also decreases.

As the flow in Figure 5 is repeated, eventually in step S2, the sway amount Q of the suspended load R becomes equal to or less than the threshold value QS (NO in step S2). In this case, the load sway control unit 902 determines whether the current height H of the suspended load R is the same as the initial height H0 (step S15). If the hook raising in step S14 and the hook lowering in step S9 have been performed the same number of times, H = H0 in step S15, and the load sway control unit 902 (sway prevention device 100) ends sway prevention control of the suspended load R.

On the other hand, if H≠H0 in step S15, in other words, H>H0, the load sway control unit 902 inputs a command signal to the winch drive unit 81 to lower the main hook 57 until H=H0. At this time, it is desirable to rotate the main hoisting winch 34 slowly to avoid generating new sway. Note that the above flow may be executed based on a preset pattern, such as performing two hook-raising operations followed by one hook-lowering operation, to prevent the load R from contacting an obstacle below through load sway prevention control.

In addition, the above explanation has been about anti-sway control of the load R when viewed from the left and right of the upper rotating body 12, but the same applies when the load R is swaying in the Y direction, or when it is swaying in both the X and Y directions. In this case, too, the sway can be similarly damped by raising and lowering the load R (main hook 57) according to the relative position of the load R and the reference line CL.

As described above, in this embodiment, the load R is raised or lowered to apply downward acceleration to the load R when it is moving toward the reference line CL, and to apply upward acceleration to the load R when it is moving away from the reference line CL, thereby reducing the kinetic energy of the load R and damping its sway. Therefore, compared to conventional methods of damping the sway of the load R by rotating the crane, the sway can be damped even in limited spaces. Furthermore, because the control unit 90 determines whether the anti-sway control is permitted or prohibited based on the switch status, it is possible to prevent the load from being erroneously raised or lowered in the prohibited state. Note that this embodiment can dampen the sway by raising or lowering the load R not only when sway of the load R occurs due to the rotation of the crane 10, but also when sway of a stationary load R occurs due to external disturbances such as wind. Furthermore, acceleration may be applied to the load R whether the sway direction is the return direction or the away direction, or only in one of these directions. It may also be applied only when the load R is located in front of the reference line CL, or only when the load R is located behind the reference line CL. Furthermore, after swaying of the load R is confirmed, acceleration may be applied to the load R at all possible times.

In addition, in this embodiment, the load R is raised and lowered using the main hoisting winch 34, which makes it difficult for horizontal movement forces to act on the load R, allowing the load R to be moved efficiently in the vertical direction, thereby damping the sway of the load. Note that, instead of the main hoisting winch 34, the auxiliary hoisting winch 36 may be used to perform sway prevention control of the load R.

In addition, in this embodiment, the control unit 90 inputs the command signal to the main hoisting winch 34 to prevent the height H of the suspended load detected by the boom angle meter 73, rope length detection unit 74, etc. from becoming lower than the initial height H0 before anti-sway control is executed. Therefore, even if there is an obstacle below the suspended load R when anti-sway control is executed, contact between the suspended load R and the obstacle can be prevented.

Furthermore, in this embodiment, the control unit 90 determines that the sway of the load R has attenuated when the sway of the load R falls within a preset tolerance range (threshold QS), and inputs the command signal to the main hoisting winch 34 so that the height H of the load R returns to the initial height H0 (step S16 in Figure 5). As a result, the sway of the load R can be attenuated and the load R can be returned to the initial height H0, allowing for a prompt transition to the next task.

Second Embodiment
Next, a sway prevention device 100 and a crane 10 according to a second embodiment of the present invention will be described. Fig. 8 is a schematic side view of the crane 10 according to this embodiment. Fig. 9 is a flowchart of swing sway prevention control for the crane 10 according to this embodiment. Figs. 10 to 13 are schematic side views for explaining sway prevention control for the suspended load R. Note that in this embodiment, differences from the first embodiment will be mainly described, and a description of common points will be omitted.

In the previous embodiment, the load R (main hook 57) was raised and lowered by winding or unwinding the main hoisting rope 50 using the main hoisting winch 34. In contrast, in this embodiment, the load R is raised and lowered by the raising and lowering operation of the boom 16. Furthermore, in this embodiment, instead of the camera 72 ( FIG. 4 ) in the first embodiment, the sway prevention device 100 has an IMU (Inertial Measurement Unit) sensor 75 (gyro sensor, load position detection unit) attached to the main hook 57. Like the camera 72, the IMU sensor 75 is used to detect the relative position of the load R with respect to the reference line CL, and can detect the sway amount Q, acceleration, etc. of the load R. Note that the IMU sensor 75 is not limited to being attached to the main hook 57. Furthermore, the sway amount Q, sway direction, position, etc. of the load R may be detected by a detection unit other than the IMU sensor 75.

Referring to FIG. 9 , in this embodiment, when the control unit 90 starts anti-sway control, the IMU sensor 75 measures the sway of the load R (step S21 in FIG. 9 ). The load sway control unit 902 then compares the acquired sway amount Q of the load R with a preset sway threshold QS (step S22). If the sway amount Q > QS (YES in step S22), the load sway control unit 902 determines that anti-sway control is required to prevent the load R from swaying. In this case, the load sway control unit 902 acquires the boom hoisting angle α detected by the boom angle meter 73 (step S23). On the other hand, if the sway amount Q ≦ QS (NO in step S22), the load sway control unit 902 determines that anti-sway control of the load R is not required and ends the anti-sway control flow.

Once the boom 16 hoisting angle α is acquired in step S23, the load sway control unit 902 calculates the position and sway direction of the suspended load R based on the information acquired by the IMU sensor 75 in step S21 (step S24). Specifically, the load sway control unit 902 calculates the sway angle θ (position) by integrating twice the acceleration detected by the IMU sensor 75, and can calculate the sway direction from the change in this angle.

Next, the load swing control unit 902 measures the height H of the suspended load R (step S25). The load swing control unit 902 also calculates the swing period T of the suspended load R (step S26). These steps are the same as those in the first embodiment. Note that the order of steps S23 to S26 can be changed as desired.

Furthermore, the load swing control unit 902 compares the boom hoisting angle α of the boom 16 acquired in step S23 with the threshold angle αs previously stored in the memory unit 903 (step S27). As an example, αs is set to 50 degrees. If α<αs (YES in step S27), the load swing control unit 902 determines whether the current up-and-down movement direction of the load R is the -Z direction (step S28). For example, if the load R is moving in the -Z direction and the +X direction (return direction), as indicated by arrow D101 in FIG. 10 (YES in step S28), the load swing control unit 902 inputs a command signal to the boom hoisting drive unit 80, rotating the boom hoist winch 30 and thereby rotating the boom 16 in the lowering direction, as indicated by arrow 102 in FIG. 10 (step S29). Note that this operation ends before the load R reaches the reference line CL. Then, the process returns to step S21.

On the other hand, in step S28, for example, if the load R is moving in the +Z direction and the -X direction (away direction) as shown by arrow D111 in Figure 11 (NO in step S28), the load swing control unit 902 inputs a command signal to the boom hoisting drive unit 80, causing the boom hoisting winch 30 to rotate, thereby rotating the boom 16 in the upright direction as shown by arrow 112 in Figure 11 (step S30). This operation ends before the load R reaches the highest point of swing. Then, the process returns to step S21.

In the processing after step S28 in Figure 9, the flow when the load R is moving in the -Z direction is the same as when the load R approaches the reference line CL while moving in the -X and -Z directions (return direction), as shown by arrow D121 in Figure 12. In this case, the load swing control unit 902 inputs a command signal to the boom hoisting drive unit 80, causing the boom hoisting winch 30 to rotate, thereby rotating the boom 16 in the lowering direction, as shown by arrow 122 in Figure 12.

Similarly, in the processing after step S28 in Figure 9, the flow when the load R is moving in the +Z direction is the same as when the load R moves away from the reference line CL while moving in the +X and +Z directions (away direction), as shown by arrow D131 in Figure 13. In this case, the load swing control unit 902 inputs a command signal to the boom hoisting drive unit 80, rotating the boom hoisting winch 30 and thereby rotating the boom 16 in the upright direction as shown by arrow 132 in Figure 13.

On the other hand, if α≧αs in step S27 of FIG. 9 (NO in step S27), the load swing control unit 902 determines whether the current load R is located in the AR region of the AF and AR regions (step S31). These regions represent the relative position of the load R in the fore-and-aft direction with respect to the reference line CL. That is, when the load R is located forward of the reference line CL in the fore-and-aft direction of the upper rotating body 12 (crane body) (prohibited state), the load R is located in the AF region (FIGS. 10 and 11). On the other hand, when the load R is located rearward of the reference line CL (closer to the upper rotating body 12) in the fore-and-aft direction of the upper rotating body 12 (permissible state), the load R is located in the AR region (FIGS. 12 and 13). The fore-and-aft direction of the upper rotating body 12 is parallel to the extension direction of the boom 16 in a plan view.

In step S31, if the load R is located in the AR area (YES in step S31, Figures 12 and 13), the load swing control unit 902 performs the same processing as in step S28. That is, if the load R is moving in the -Z direction and the -X direction as shown by arrow D121 in Figure 12 (YES in step S32), the load swing control unit 902 inputs a command signal to the boom hoisting drive unit 80, causing the boom hoist winch 30 to rotate, thereby rotating the boom 16 in the lowering direction as shown by arrow 122 in Figure 12. Also, in step S32, if the load R is moving in the +Z direction and the +X direction as shown by arrow D131 in Figure 13 (NO in step S32), the load swing control unit 902 inputs a command signal to the boom hoisting drive unit 80, causing the boom hoist winch 30 to rotate, thereby rotating the boom 16 in the raising direction as shown by arrow 132 in Figure 13.

On the other hand, if the load R is located in the AF area in step S31 (NO in step S31, Figures 10 and 11), the load sway control unit 902 maintains the angle of the boom 16 without performing a hoisting operation of the boom 16, and returns to step S21. In other words, the load sway control unit 902 suspends anti-sway control. The reason for this processing is described in detail below.

When the boom 16 is raised and lowered by a predetermined angle with a small boom hoisting angle α, the movement of the load R is dominated by movement in the vertical direction. On the other hand, when the boom 16 is raised and lowered by a predetermined angle with a large boom hoisting angle α, movement of the load R not only in the vertical direction but also in the fore-and-aft direction (horizontal direction) cannot be ignored. The above processing takes this into consideration.

Specifically, as shown in Figure 10, when the boom 16 is rotated in the lowering direction while the load R is moving toward the reference line CL in the AF region, the tip of the boom 16 accelerates in the -X and -Z directions, but the load R, which is moving as described above, accelerates in the +X and -Z directions. In this case, as viewed from the load R, the acceleration in the up-and-down direction is attenuated, but the acceleration in the fore-and-aft direction (horizontal direction) actually increases due to the movement of the tip of the boom. Also, as shown in Figure 11, when the load R is moving away from the reference line CL in the AF region and the boom 16 is rotated in the up-and-down direction, the tip of the boom 16 accelerates in the +X and +Z directions, but the load R, which is moving as described above, accelerates in the -X and +Z directions. In this case, too, as viewed from the load R, the acceleration in the up-and-down direction is attenuated, but the acceleration in the fore-and-aft direction actually increases.

On the other hand, as shown in Figure 12, when the boom 16 is rotated in the lowering direction while the load R is moving toward the reference line CL in the AR region, the tip of the boom 16 accelerates in the -X and -Z directions, but the moving load R also accelerates in the -X and -Z directions as described above. In this case, acceleration is attenuated in both the up-down and forward-backward directions as viewed from the load R. Similarly, as shown in Figure 13, when the boom 16 is rotated in the upright direction while the load R is moving away from the reference line CL in the AR region, the tip of the boom 16 accelerates in the +X and +Z directions, but the moving load R also accelerates in the +X and +Z directions as described above. In this case, acceleration is also attenuated in both the up-down and forward-backward directions as viewed from the load R.

As described above, in this embodiment, vibration is damped by applying acceleration to the load R, which attenuates the acceleration of kinetic energy in accordance with the law of conservation of energy and reduces the total energy of the load R. However, if the boom 16 has a large hoisting angle α and the load R is located in the AF area, the hoisting operation of the boom 16 increases the acceleration of the load R in the fore-and-aft direction, increasing the energy of the load R. For this reason, in this embodiment, the hoisting operation of the boom 16 is performed only when the load R is located in the AR area. Note that the function of adjusting the height of the load R in the first embodiment can also be applied to this embodiment.

In this embodiment, as in the first embodiment, the load R is raised or lowered so that a downward acceleration is applied to the load R when the load R is moving toward the reference line CL, and an upward acceleration is applied to the load R when the load R is moving away from the reference line CL, thereby reducing the kinetic energy of the load R and damping its sway. Therefore, compared to conventional methods of damping the sway of the load R by rotating the crane, the sway can be damped even in a limited space.

In addition, in this embodiment, because the load is raised and lowered by the boom 16 raising and lowering operation, the sway of the load R can be damped even if there are restrictions on the rope winding and payout operations by the main winch 34 and the auxiliary winch 36 at the work site. As an example, in a situation where paying out more rope than the current payout amount would cause the rope to run out of the winch and the winding direction of the rope on the winch to reverse, it is desirable to raise and lower the load by the boom 16 raising and lowering operation as in this embodiment.

In addition, in this embodiment, if the boom hoisting angle α detected by the boom angle meter 73 is smaller than a preset threshold angle αs, the control unit 90 determines that the state is permissible regardless of the relative position of the load R to the reference line CL detected by the camera 72. In other words, when the boom hoisting angle α of the boom 16 is relatively small, the sway of the load R is less likely to worsen even when the boom 16 is hoisted. This makes it possible to actively execute anti-sway control regardless of the relative position of the load R to the reference line CL.

On the other hand, when the boom hoisting angle α detected by the boom angle meter 73 is greater than the threshold angle αs, the control unit 90 determines that the state is prohibited when the relative position of the load R detected by the camera 72 is forward of the reference line CL, and determines that the state is permissible when the relative position of the load R is rearward of the reference line CL. In other words, when the boom hoisting angle α is relatively large, anti-sway control is performed only when the load R is rearward of the reference line CL, thereby preventing the sway of the load R from increasing while attenuating the sway.

The above describes the anti-sway device 100 and the crane 10 equipped with the same according to each embodiment of the present invention. However, the present invention is not limited to these embodiments. The present invention can take on modified embodiments such as the following:

(1) The structure of the crane to which the anti-sway device 100 of the present invention is applied is not limited to the crane 10 shown in FIG. 1, and may be a crane with a different structure. In other words, the crane to which the present invention is applied may be one equipped with a lattice mast or gantry, or one in which a hoisting winch is located on the upper frame (rear side) of the upper rotating body 12. The crane may also be one in which a jib or strut is attached to the tip of the boom.

(2) In the second embodiment described above, anti-sway control is performed only when the load R is located in the AR area when the boom 16 hoisting angle is large. However, when the boom 16 hoisting angle α is large, the control of the second embodiment may be switched to the control of the first embodiment, and the sway of the load R may be damped by winding and unwinding the main hoisting rope 50 (rope).

(3) Furthermore, when applying a predetermined acceleration to the load R, the control unit 90 may calculate the swing period T of the load R as described above, and input the command signal to the main hoisting winch 34 and the boom hoisting winch 30 so as to adjust the lifting and lowering speed of the load R in accordance with the calculated period T.

With this configuration, the time required to damp the sway can be reduced by adjusting the lifting/lowering speed according to the sway period T of the load R. In particular, when the sway period T of the load R is long, there is ample time to perform sway prevention control, so by setting a large acceleration to the load R, the damping of the sway of the load R can be accelerated. Furthermore, when the sway period T of the load R is short, by reducing the acceleration of the load R, it is possible to prevent the load R from reaching the reference line CL or the highest point of the sway during sway prevention control, and erroneously applying acceleration in the opposite direction to the load R.

10 Crane 100 Anti-sway device 12 Upper rotating body (crane body)
14 Running body 15 Cab 16 Boom (elevating body)
16S Boom foot 20 Mast 30 Boom raising winch (hoisting device)
34 Main winch (load winch)
50 Main hoisting rope (rope)
57 Main hook 57M Marker 70 Operation unit 71 Input unit 72 Camera (hanging load position detection unit)
73 Boom angle meter (boom angle detector, lifting load height detector)
74 Rope length detector (hanging load height detector)
75 IMU sensor (hanging load position detection unit)
80 Boom hoisting drive unit (lifting unit)
81 Winch drive unit (lifting unit)
82 Swing drive unit 90 Control unit 901 Drive control unit 902 Load swing control unit 903 Memory unit CL Reference line R Suspended load

Claims (9)

A crane anti-sway device that is used in a crane having a crane body, a rope suspended from a predetermined fulcrum and connected to a suspended load, a lifting section that can receive a command signal and raise or lower the suspended load via the rope in accordance with the command signal , and an elevation body that includes the fulcrum and a support point spaced from the fulcrum and is supported at the support point on the crane body , and that is capable of executing anti-sway control to suppress sway of the suspended load,
a load position detection unit capable of detecting the relative position of the load with respect to a reference line that passes through the fulcrum and extends in a vertical direction;
Determining a swing state of the suspended load based on the relative position of the suspended load detected by the suspended load position detection unit , and
When the swing state is a first state indicating that the load is approaching the support point while approaching the reference line, the command signal for lowering the load is input to the lifting unit so that a downward acceleration is applied to the load,
When the swing state is a second state indicating that the load is approaching the reference line and moving away from the support point, the command signal for lowering the load is input to the lifting unit so that a downward acceleration is applied to the load,
When the swing state is a third state indicating that the load is moving away from the reference line and approaching the support point , the command signal for raising the load is input to the lifting unit so that an upward acceleration is applied to the load ,
A crane sway prevention device comprising: a control unit that, when the sway state is a fourth state indicating that the load is moving away from the reference line and the support point, inputs the command signal to the lifting unit to raise the load so that an upward acceleration is applied to the load . The lifting unit includes a load winch that can lift the load by winding up the rope and lower the load by letting out the rope,
2. The anti-sway device for a crane according to claim 1 , wherein the control unit inputs the command signal to the lifting unit so that the rope is let out by the load winch when the sway state is either the first state or the second state, and the rope is reeled in by the load winch when the sway state is either the third state or the fourth state. The hoisting body is supported by the crane body so as to be able to be hoisted and hoisted,
the lifting unit includes a lifting device capable of rotating the lifting body in a lifting direction,
2. The anti-sway device for a crane as described in claim 1 , wherein the control unit inputs the command signal to the lifting unit so that the hoisting device rotates the hoisting body in a lowering direction when the sway state is either the first state or the second state , and so that the hoisting device rotates the hoisting body in an upright direction when the sway state is either the third state or the fourth state. A crane sway prevention device that is used in a crane having a crane body, a rope suspended from a predetermined fulcrum and connected to a suspended load, a lifting section that can receive a command signal and raise or lower the suspended load via the rope in accordance with the command signal, and a hoisting body that includes the fulcrum and is supported on the crane body so that it can be raised or lowered, and that is capable of performing sway prevention control to suppress sway of the suspended load,
a control unit that determines the swing direction of the suspended load, and when the swing direction is a return direction approaching a reference line that passes through the fulcrum and extends in a vertical direction, inputs the command signal to the lifting unit to lower the suspended load so that a downward acceleration is applied to the suspended load, and when the swing direction is a direction away from the reference line, inputs the command signal to the lifting unit to raise the suspended load so that an upward acceleration is applied to the suspended load;
an elevation angle detection unit capable of detecting an elevation angle of the undulating body;
a load position detection unit capable of detecting a relative position of the load with respect to the reference line in the front-rear direction of the crane body;
Equipped with
the lifting unit includes a lifting device capable of rotating the lifting body in a lifting direction,
The control unit
inputting the command signal to the lifting unit so that the undulating body is rotated in a falling direction by the undulating device when the swing direction is the returning direction, and so that the undulating body is rotated in an upright direction by the undulating device when the swing direction is the separating direction;
Furthermore, when the elevation angle detected by the elevation angle detection unit is greater than a preset threshold value and the relative position of the load detected by the load position detection unit is behind the reference line, the command signal is input to the lifting unit, but when the relative position of the load is ahead of the reference line , the input of the command signal to the lifting unit is withheld. A crane sway prevention device as described in claim 4, wherein the control unit inputs the command signal to the lifting unit regardless of the relative position of the suspended load detected by the suspended load position detection unit when the hoisting angle detected by the hoisting angle detection unit is smaller than the threshold value. A crane sway prevention device that is used in a crane having a crane body, a rope suspended from a predetermined fulcrum and connected to a suspended load, and a lifting unit that can receive a command signal and raise or lower the suspended load via the rope in accordance with the command signal, and that can perform sway prevention control to suppress sway of the suspended load,
a control unit that determines the swing direction of the suspended load, and when the swing direction is a return direction approaching a reference line that passes through the fulcrum and extends in a vertical direction, inputs the command signal to the lifting unit to lower the suspended load so that a downward acceleration is applied to the suspended load, and when the swing direction is a direction away from the reference line, inputs the command signal to the lifting unit to raise the suspended load so that an upward acceleration is applied to the suspended load;
a load height detection unit capable of detecting the height of the load relative to the ground when the load is stationary on the reference line,
The control unit inputs the command signal to the lifting unit so as to prevent the height of the suspended load detected by the suspended load height detection unit from becoming lower than an initial height , which is the height of the suspended load before the anti-sway control is executed. A crane sway prevention device as described in claim 6, wherein the control unit inputs the command signal to the lifting unit so that the height of the suspended load returns to the initial height when the sway of the suspended load falls within a preset tolerance range and the height of the suspended load differs from the initial height. A crane sway prevention device that is used in a crane having a crane body, a rope suspended from a predetermined fulcrum and connected to a suspended load, and a lifting unit that can receive a command signal and raise or lower the suspended load via the rope in accordance with the command signal, and that can perform sway prevention control to suppress sway of the suspended load,
a control unit that determines the swing direction of the suspended load, and when the swing direction is a return direction approaching a reference line that passes through the fulcrum and extends in a vertical direction, inputs the command signal to the lifting unit to lower the suspended load so that a downward acceleration is applied to the suspended load, and when the swing direction is a direction away from the reference line, inputs the command signal to the lifting unit to raise the suspended load so that an upward acceleration is applied to the suspended load,
The control unit calculates the period of swing of the suspended load and inputs the command signal to the lifting unit so as to adjust the magnitude of acceleration applied to the suspended load in accordance with the calculated period . The crane body,
A rope suspended from a predetermined fulcrum and connected to a suspended load;
a lifting unit that receives a command signal and lifts or lowers the suspended load in response to the command signal;
The anti-sway device for a crane according to any one of claims 1 to 8, which is capable of executing anti-sway control to suppress sway of the suspended load;
A crane equipped with: