Crane control device and crane

Abstract

To provide a crane control device capable of preventing loss of work speed by an attachment as a result of turning angular acceleration being more restricted than necessary from the perspective of strength and safety of the attachment when an upper rotating body is accelerated and decelerated.SOLUTION: A control device executes driving control of a turning drive unit to meet predetermined acceleration conditions in which circumferential lateral acceleration of a load support unit of a crane falls below maximum allowable lateral acceleration. The maximum allowable lateral acceleration is set on the basis of a ratio of maximum allowable lateral load of the load support unit relative to a strength allowable weight in a first work radius area where the strength allowable weight becomes smaller than a stable allowable weight, while it is set on the basis of a ratio of maximum allowable lateral load of the load support unit relative to the stable allowable weight in a second work radius area where the stable allowable weight becomes smaller than the strength allowable weight.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a crane control device and a crane. [Background technology]

[0002] Conventionally, a crane has been known that has an upper rotating body that is rotatably supported on a lower body, attachments such as a boom and a jib that are installed on the upper rotating body, and a rotating drive unit that drives the upper rotating body to rotate.

[0003] Patent Document 1 listed below discloses a control device used to control this type of crane. This control device derives an allowable angular acceleration of the upper rotating body that corresponds to the boom's swing-resistant torque, and controls the swing drive unit so as to limit the actual swing angular acceleration of the upper rotating body within the range of the derived allowable angular acceleration (see paragraphs

[0096] to

[0111] of Patent Document 1, etc.). The control device multiplies the allowable angular acceleration by the sum of the boom's moment of inertia, which changes depending on the swing radius (the radius corresponding to the boom hoisting angle), and the moment of inertia of the load, and calculates the allowable angular acceleration so that the torque obtained matches the swing-resistant torque. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-079903 Summary of the Invention [Problem to be solved by the invention]

[0005] The crane control system shown in Patent Document 1 ensures the strength and safety of the attachment by setting an allowable angular acceleration corresponding to the swing torque resistance of the boom (attachment). However, this control system does not take into account the effect of the crane's maximum allowable weight (rated load), which varies depending on the working radius. As a result, depending on the working radius, the swing angular acceleration during acceleration and deceleration of the upper rotating body is restricted more than necessary regardless of the weight of the load, resulting in a problem of reduced speed of work using the attachment.

[0006] The present invention has been made to solve the above-mentioned problems, and its purpose is to prevent the rotational angular acceleration from being restricted more than necessary from the standpoint of strength safety of the attachment when the upper rotating body accelerates or decelerates, thereby preventing the speed of work performed by the attachment from being impaired. [Means for solving the problem]

[0007] A first invention is a crane control device used for a crane including a lower body, an upper rotating body supported on the lower body so as to be rotatable about a rotation axis extending in a vertical direction relative to the lower body, an attachment connected to the upper rotating body and having a load support part that supports a load via a vertically hanging load rope, and a rotation drive part that can rotate the upper rotating body about the rotation axis relative to the lower body, the crane control device including a rotation control part that executes drive control of the rotation drive part, and a working radius acquisition part that acquires a working radius that is the horizontal distance between the rotation axis of the upper rotating body and the load support part of the attachment, and the rotation control part is configured to acquire a maximum allowable value of the lateral acceleration of the load support part in the circumferential direction when the rotation drive part accelerates and decelerates the upper rotating body in the circumferential direction about the rotation axis, the maximum allowable value being determined according to the working radius. The system is configured to execute drive control of the slewing drive unit so as to satisfy a predetermined acceleration condition that the acceleration is below the maximum allowable lateral acceleration, and the maximum allowable lateral acceleration is set based on the ratio of the maximum allowable lateral load in the circumferential direction of the load support part to the strength allowable weight in a first working radius region smaller than a predetermined working radius where the strength allowable weight, which is the maximum allowable weight of the load set based on the strength limit of the attachment, is equal to the stable allowable weight, which is the maximum allowable weight of the load set based on the attitude stability limit of the attachment, and where the strength allowable weight is smaller than the stable allowable weight, while the maximum allowable lateral acceleration is set based on the ratio of the maximum allowable lateral load in the circumferential direction of the load support part to the stable allowable weight in a second working radius region larger than the predetermined working radius where the stable allowable weight is smaller than the strength allowable weight.

[0008] This configuration prevents the rotation angular acceleration of the upper rotating body, which is rotated by the rotation drive unit, from being unnecessarily limited, thereby preventing a loss of speed in work using the attachment. That is, with this configuration, the upper rotating body is driven by the rotation drive unit so that the circumferential lateral acceleration acting on the load support unit is equal to or less than the maximum allowable lateral acceleration during circumferential deceleration and acceleration of the upper rotating body. The maximum allowable lateral acceleration of the load support unit is set based on the ratio of the maximum allowable circumferential lateral load of the load support unit to the strength allowable weight in a first working radius range (a radius range in which the rated load of the load is limited by the strength allowable weight) in which the strength allowable weight of the load is smaller than the stable allowable weight, and is set based on the ratio of the maximum allowable circumferential lateral load of the load support unit to the stable allowable weight in a second working radius range (a radius range in which the rated load of the load is limited by the stable allowable weight) in which the stable allowable weight is smaller than the strength allowable weight. Therefore, in each working radius range, the maximum allowable lateral acceleration of the load support unit is set based on the ratio (allowable lateral load rate) of the maximum allowable lateral load to the smaller of the strength allowable weight and the stability allowable weight, which limit the weight of the load. Therefore, compared to a case where the maximum allowable lateral acceleration is set based on, for example, the ratio (allowable lateral load rate) of the maximum allowable lateral load to the larger of the strength allowable weight and the stability allowable weight, the maximum allowable lateral acceleration of the load support unit can be increased by the amount corresponding to the lighter maximum weight of the reference load. When the maximum allowable lateral acceleration of the load support unit is increased, the maximum allowable angular acceleration of the upper rotating body during acceleration and deceleration of the upper rotating body can be increased accordingly, thereby preventing unnecessary decreases in the rotation angular acceleration of the upper rotating body caused by the rotation drive unit. This in turn prevents a loss of speed in work using the attachment.

[0009] In a second invention, in the first invention, when the working radius acquired by the working radius acquisition unit is within the second working radius range, it is preferable that the turning control unit performs drive control of the turning drive unit so as to reduce the convergence time, which is the time from the start of each operation to the end of each operation when causing the turning drive unit to perform the acceleration and deceleration operations, the larger the working radius.

[0010] This configuration, when the upper rotating body is accelerated and decelerated to satisfy a predetermined acceleration condition (when the configuration of the first invention is adopted), can suppress an increase in the travel distance of the load support unit during acceleration / deceleration (an increase in braking distance in the case of deceleration) caused by an increase in the angular acceleration of the upper rotating body in the second working radius range compared to conventional cases. In other words, if the angular acceleration of the upper rotating body is increased while maintaining a constant convergence time for the acceleration / deceleration operation, the travel distance of the load support unit during acceleration / deceleration increases. While this increase in travel distance increases in proportion to the working radius, this configuration can suppress this increase in travel distance by reducing the convergence time for acceleration / deceleration in the second working radius range as the working radius increases. Therefore, the positioning performance of the attachment during acceleration / deceleration of the upper rotating body can be improved. In particular, during deceleration, the braking distance (travel distance) of the load support unit of the attachment is reduced, thereby improving the stopping position accuracy of the attachment (load).

[0011] A third invention is the first or second invention, wherein the crane has an operation unit that receives an operation for rotating the upper rotating body and outputs an operation signal, and when the operation control unit detects that the operation unit has been operated based on the operation signal from the operation unit, it executes drive control of the rotation drive unit to accelerate the upper rotating body to a rotation angular velocity corresponding to the amount of operation, and when the operation is released, it executes drive control of the rotation drive unit to decelerate the upper rotating body until it stops rotating, and when a non-full operation with a smaller amount of operation than a full operation is executed on the operation unit, it is preferable that the convergence time, which is the time from the start of the operation to the end of the operation, is reduced so that the rotation angular acceleration of the upper rotating body does not change when at least one of the acceleration operation and the deceleration operation is executed, compared to when the full operation is executed.

[0012] According to this configuration, when a non-full operation, which is a smaller operation amount than a full operation, is performed on the operating unit, the convergence time for at least one of the acceleration and deceleration operations of the upper rotating body is shorter than that during full operation. This allows for quick acceleration and deceleration of the upper rotating body, improving the workability of the attachment. In particular, the reduced deceleration time during deceleration reduces the circumferential braking distance of the attachment (load support unit). This improves the stopping position accuracy of the attachment and improves safety. Furthermore, with this configuration, the rotation angular acceleration during a non-full operation remains unchanged compared to full operation, so the lateral load acting on the suspension support unit does not increase. Therefore, the stopping position accuracy of the attachment can be improved while preventing damage to the attachment due to the lateral load during the rotation of the upper rotating body.

[0013] A fourth invention is preferably the first or second invention, further comprising a weight acquisition unit that acquires the weight of the load and a memory unit that stores the rated load of the load, wherein the rated load of the load is preset according to the working radius so that it matches the strength allowable weight in the first working radius range and the stability allowable weight in the second working radius range, and the maximum allowable lateral acceleration specified in the specified acceleration condition is set so that when the weight of the load is smaller than the rated load, it is higher by the ratio between the weight of the load and the rated load compared to when the weight of the load is equal to the rated load, and the slewing drive unit is configured to acquire the rated load of the load corresponding to the working radius based on the working radius acquired by the working radius acquisition unit, and to perform drive control of the slewing drive unit so as to satisfy the specified acceleration condition based on the ratio between the acquired rated load and the weight of the load acquired by the weight acquisition unit.

[0014] According to this configuration, when the weight of the suspended load is smaller than the rated load, the maximum allowable lateral acceleration of the load support part is set higher by the ratio of the rated load to the weight of the suspended load, so the maximum allowable angular acceleration of the upper rotating body can be increased by the ratio without changing (increasing) the lateral load acting on the suspension support part compared to when the weight of the suspended load is equal to the rated load. Therefore, the upper rotating body can be accelerated and decelerated quickly, improving workability using attachments.

[0015] The fifth invention, in the first or second invention, preferably further comprises an inertia moment acquisition unit that acquires the moment of inertia about the rotation axis of a group of rotating objects including the upper rotating body, the attachment, and the suspended load, and the rotation control unit is configured to, when a limiting angular acceleration, which is the upper limit value of the angular acceleration in the circumferential direction of the group of rotating objects determined based on the moment of inertia acquired by the inertia moment acquisition unit and the maximum output torque about the rotation axis that the rotation drive unit can output, is smaller than a maximum allowable angular acceleration determined based on the maximum allowable lateral acceleration and the working radius, execute drive control of the rotation drive unit so that the rotation angular acceleration of the upper rotating body is equal to or less than the limiting angular acceleration, and, when the limiting angular acceleration is equal to or greater than the maximum allowable angular acceleration, execute drive control of the rotation drive unit so that the rotation angular acceleration of the upper rotating body is equal to or less than the maximum allowable angular acceleration.

[0016] According to this configuration, if the limit angular velocity determined by the maximum output torque of the slewing drive unit and the moment of inertia of the group of slewing objects is smaller than the maximum allowable angular acceleration of the upper slewing body that satisfies the specified acceleration condition, the slewing angular acceleration of the upper slewing body is limited to be less than the limit angular acceleration, thereby preventing the slewing control unit from unnecessarily performing control processing (calculation processing) to satisfy the specified acceleration condition, thereby preventing an increase in the calculation burden.

[0017] The sixth invention is the first or second invention, and when the rotation control unit decelerates the upper rotating body, it is preferable that the rotation control unit executes a first calculation process to calculate, as a target convergence time, the convergence time from the start of the deceleration operation to the end of the operation when the upper rotating body is decelerated at the maximum allowable angular acceleration that satisfies the predetermined acceleration condition, and a second calculation process to calculate, as a predicted convergence time Td using equation (1), the convergence time for starting the deceleration operation from the current time and stopping the upper rotating body at a predetermined target swing angle θt, when the circumferential swing angle of the upper rotating body at the current time is θs and the swing angular velocity of the upper rotating body at the current time is ωs, and executes drive control of the rotation drive unit so as to start the deceleration operation of the upper rotating body when the predicted convergence time Td matches the target convergence time. Td=2×(θt-θs) / ωs………Formula (1)

[0018] According to this configuration, when stopping the upper rotating body, by starting the deceleration operation of the upper rotating body at a timing that satisfies the above formula (1), the upper rotating body can be stopped at a predetermined target rotation angle while decelerating at the maximum allowable angular acceleration that satisfies the above predetermined acceleration condition. This control is particularly useful when controlling automatic operation of a crane.

[0019] The seventh invention is, in the first or second invention, preferably, wherein the slewing drive unit has a variable displacement hydraulic motor, a hydraulic pump that discharges hydraulic oil to the hydraulic motor, a hydraulic circuit that connects the hydraulic pump and the hydraulic motor, and a control valve that is provided in the hydraulic circuit and controls the flow rate of hydraulic oil from the hydraulic pump to the hydraulic motor, and the slewing control unit performs drive control of the hydraulic motor by performing at least one of controlling the opening of the control valve, controlling the capacity of the hydraulic pump, and controlling the hydraulic pressure of the hydraulic circuit.

[0020] According to this configuration, by configuring the rotation drive unit with hydraulic equipment, the rotation angular velocity and rotation angular acceleration of the upper rotating body can be easily controlled.

[0021] The eighth invention is the first or second invention, further comprising an emergency stop operation unit that outputs an emergency stop signal for bringing the upper rotating body to an emergency stop when a predetermined operation is received by an operator while the upper rotating body is rotating, and the rotating drive unit has a variable displacement hydraulic motor, a hydraulic pump that discharges hydraulic oil to the hydraulic motor, a hydraulic circuit that connects the hydraulic pump and the hydraulic motor, a control valve provided in the hydraulic circuit that controls the flow rate of hydraulic oil from the hydraulic pump to the hydraulic motor, and an engine that drives the hydraulic pump, and when the rotating control unit receives the emergency stop signal from the emergency stop operation unit while the upper rotating body is rotating, it is preferable that the rotating control unit stops the engine to stop the rotating drive unit, and sets a convergence time from the start to the end of the deceleration operation when the upper rotating body is decelerated at a maximum allowable angular acceleration that satisfies the predetermined acceleration condition, and executes drive control of the rotating drive unit so as to transition the control valve from an open state to a closed state within the set convergence time.

[0022] With this configuration, even when the emergency stop operating unit is operated, the upper rotating body is not immediately stopped by the rotation drive unit, but rather the upper rotating body can be stopped by ensuring a convergence time for decelerating the upper rotating body at the maximum allowable angular acceleration that satisfies the predetermined acceleration condition. Therefore, the upper rotating body can be stopped quickly without damaging the attachment due to the lateral load of the suspended load that occurs when the upper rotating body decelerates.

[0023] The ninth invention relates to a crane comprising a lower body, an upper rotating body supported on the lower body so as to be rotatable about a rotation axis extending in the vertical direction relative to the lower body, an attachment connected to the upper rotating body and having a load support part that supports a load via a vertically hanging load rope, a rotation drive part that can rotate the upper rotating body about the rotation axis relative to the lower body, and a control device according to the first or second invention.

[0024] According to this crane, it is possible to obtain the same effects as those of the first aspect of the invention. [Effects of the Invention]

[0025] According to the present invention, it is possible to prevent the rotation angular acceleration from being restricted more than necessary from the viewpoint of the strength safety of the attachment when the upper rotating body is accelerated or decelerated, thereby preventing a loss of speed in work by the attachment. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a side view of a crane equipped with a control device according to a first embodiment. [Figure 2] FIG. 2 is a hydraulic circuit diagram of a slewing drive unit of the crane in the first embodiment. [Figure 3] 1 is a block diagram showing the configuration of a control system including a control device according to a first embodiment. [Figure 4] FIG. 4 is a diagram showing an example of a rated load map stored in a storage unit. [Figure 5A] FIG. 2 is a side view schematically showing the crane. [Figure 5B] FIG. 2 is a plan view schematically showing a crane. [Figure 5C] FIG. 10 is a side view seen from the outside in the direction of the turning radius, schematically showing a state in which a load is supported at the tip of the attachment via a load rope. [Figure 6A] 10 is a graph showing the relationship between working radius and maximum allowable lateral acceleration. [Figure 6B] 10 is a graph showing the relationship between the working radius and the maximum allowable lateral speed. [Figure 6C] FIG. 10 is a diagram illustrating an example of a convergence time map. [Figure 6D] 10 is a graph showing the calculation results of the braking distance of the tip of the attachment. [Figure 6E] FIG. 10 is a diagram showing an example of a maximum allowable angular velocity map that defines the relationship between the maximum allowable angular velocity of an upper rotating body and a working radius. [Figure 7] 5 is a flowchart showing the contents of drive control of the swivel drive unit executed by the control device. [Figure 8A]10 is a time chart showing an example of a velocity profile of a swing angular velocity when the control device controls the swing of the upper swing body. [Figure 8B] 8B is a time chart showing the time change in the rotation angular acceleration of the upper rotating body corresponding to the velocity profile of FIG. 8A. [Figure 9] 5 is a time chart for explaining an example of drive control of the swivel drive unit by the swivel control unit. [Figure 10A] FIG. 6B is a view showing the second embodiment, corresponding to FIG. 6A. [Figure 10B] FIG. 6B is a view showing the second embodiment, corresponding to FIG. 6B. [Figure 10C] FIG. 6C shows the second embodiment. [Figure 10D] FIG. 6D shows the second embodiment. [Figure 10E] FIG. 6B is a view showing the second embodiment, corresponding to FIG. 6E. [Figure 11A] FIG. 8B is a view showing the third embodiment, corresponding to FIG. 8A. [Figure 11B] FIG. 8B is a view showing the third embodiment, corresponding to FIG. 8B. [Figure 12A] FIG. 11B is a view corresponding to FIG. 11A and shows a modified example of the third embodiment. [Figure 12B] FIG. 11B is a view showing a modification of the third embodiment, corresponding to FIG. [Figure 13] FIG. 10 is a view corresponding to FIG. 7 and shows a fourth embodiment. [Figure 14] FIG. 10 is a view equivalent to FIG. 3 and shows a fifth embodiment. [Figure 15] 1 is a graph in which the horizontal axis represents the total moment of inertia and the vertical axis represents the turning angular acceleration, and the solid line represents the limit angular acceleration determined by the maximum torque that the turning drive unit can output. [Figure 16] FIG. 10 is a view equivalent to FIG. 3 and shows a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0027] (Embodiment 1) Hereinafter, each embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a side view of a crane 10 equipped with a control device 80 according to a first embodiment of the present invention. Note that, although directions such as "up," "down," "front," and "rear" are shown in each drawing hereinafter, these directions are shown for the sake of convenience in explaining the structure and assembly method of the crane 10 according to each embodiment, and do not limit the direction of movement or usage of the crane according to the present invention.

[0028] The crane 10 comprises an upper rotating body 12 corresponding to the crane body, a lower running body 14 (lower body) that rotatably supports the upper rotating body 12, an attachment 10S (also called a hoisting body) that includes a boom 16 and a jib 18, and a mast 20 that is a boom hoisting member. The upper rotating body 12 is supported by the lower running body 14 so as to be rotatable about a rotation axis CL that extends in the vertical direction relative to the lower running body 14. 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 provided at the front end of the upper rotating body 12. The cab 15 corresponds to the driver's seat of the crane 10.

[0029] The attachment 10S includes a base end portion supported on the upper rotating body 12 so as to be rotatable in the hoisting direction, and a tip end portion opposite the base end portion, and is detachable from the upper rotating body 12. As described above, in this embodiment, the attachment 10S includes the boom 16 and the jib 18.

[0030] The boom 16 shown in FIG. 1 is a so-called lattice type and is composed of a lower boom 16A, one or more (three in the illustrated example) intermediate booms 16B, 16C, and 16D, and an upper boom 16E. Specifically, the lower boom 16A is connected to the front of the upper rotating structure 12 so as to be rotatable in the hoisting direction. The intermediate booms 16B, 16C, and 16D are detachably attached to the tip of the lower boom 16A in that order. The upper boom 16E is detachably attached to the tip of the intermediate boom 16D, and the jib 18, and the rear strut 21 and front strut 22 for rotating the jib 18 are rotatably connected to the tip of this upper boom 16E, respectively. The boom 16 is rotatably supported by the upper rotating structure 12 around a rotation axis extending in the left-right direction with a boom foot pin 16S provided at the lower end as a fulcrum.

[0031] The boom 16 has an intermediate boom sheave 46 and idler sheaves 32S, 34S, and 36S. The intermediate boom sheave 46 is disposed on the rear surface of the tip end of the intermediate boom 16D. The idler sheave 32S, idler sheave 34S, and idler sheave 36S are rotatably supported on the rear surface of the base end of the boom 16.

[0032] However, the present invention is not limited to a specific boom structure. For example, the boom may have no intermediate members, or may have a different number of intermediate members than those described above. Furthermore, the boom may be constructed of a single member.

[0033] The specific structure of the jib 18 is also not limited. The base end of the jib 18 is rotatably connected (pivoted) to the tip end of the upper boom 16E of the boom 16, and the rotation axis of the jib 18 is a horizontal axis parallel to the rotation axis (boom foot pin 16S) of the boom 16 relative to the upper rotating body 12.

[0034] The mast 20 has a base end and a pivoting end, and the base end is pivotally connected to the upper rotating body 12. The pivoting axis of the mast 20 is parallel to the pivoting axis of the boom 16 and is located immediately rearward of the pivoting axis of the boom 16. In other words, the mast 20 is pivotable in the same direction as the boom 16 is raised and lowered. Meanwhile, the pivoting end of the mast 20 is connected to the tip of the boom 16 via a pair of boom guy lines 24 on the left and right. This connection coordinates the rotation of the mast 20 and the rotation of the boom 16.

[0035] Furthermore, the crane 10 is equipped with a pair of left and right backstops 23, a rear strut 21, a front strut 22, a pair of left and right strut backstops 25 and guy lines 26, and a pair of left and right jib guy lines 28.

[0036] 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 come into contact with 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 contact prevents the boom 16 from being blown backward by strong winds, etc.

[0037] The rear strut 21 is pivotally supported at the tip of the boom 16. The rear strut 21 is held in a position where it extends from the tip of the upper boom 16E toward the boom-raising side (left side in FIG. 1 ) from the tip of the upper boom 16E. To maintain this position, a pair of left and right strut backstops 25 and a pair of left and right guy lines 26 are interposed between the rear strut 21 and the boom 16. The strut backstops 25 are interposed between the intermediate boom 16D and the middle section of the rear strut 21, supporting the rear strut 21 from below. The guy lines 26 are tensioned to connect the tip of the rear strut 21 to the lower boom 16A of the boom 16, and their tension regulates the position of the rear strut 21. The rear strut 21 also has a sheave block 47 and rear strut idler sheaves 52 and 62. The sheave block 47 is located at the pivoting end of the rear strut 21 and includes multiple sheaves arranged in the width direction. The rear strut idler sheaves 52, 62 are arranged in a portion of the rear strut 21 that is closer to the base end than the longitudinal center portion, and each includes a plurality of sheaves arranged in the width direction.

[0038] The front strut 22 is disposed rearward of the jib 18 and is pivotally supported on the tip of the boom 16 (upper boom 16E) so as to rotate in conjunction with the jib 18. Specifically, a pair of left and right jib guy lines 28 are tensioned to connect the tip of the front strut 22 to the tip of the jib 18. Therefore, when the front strut 22 rotates, the jib 18 is also rotated integrally with the front strut 22. As shown in FIG. 1 , the rear strut 21 is disposed rearward of the front strut 22 and forms a substantially isosceles triangle shape with the front strut 22. The front strut 22 has a sheave block 48 and front strut idler sheaves 53, 63. The sheave block 48 is disposed at the rotating end of the front strut 22 and includes a plurality of sheaves arranged in the width direction. The front strut idler sheaves 53, 63 are arranged in a portion of the front strut 22 that is closer to the base end than the longitudinal center portion, and each includes a plurality of sheaves arranged in the width direction.

[0039] The crane 10 further includes various winches. Specifically, the crane 10 includes a boom hoist winch 30 for raising and lowering the boom 16, a jib hoist winch 32 for rotating the jib 18 in the hoisting direction, and a main hoist winch 34 and an auxiliary hoist winch 36 for hoisting and lowering a load. The crane 10 also includes a boom hoist rope 38, a jib hoist rope 44, a main hoist rope 50 (an example of a load rope), and an auxiliary hoist rope 60. In the crane 10 according to this embodiment, the jib hoist winch 32, the main hoist winch 34, and the auxiliary hoist winch 36 are installed near the base end of the boom 16. The boom hoist winch 30 is also installed on the upper rotating body 12. The locations of these winches 30, 32, 34, and 36 are not limited to those described above.

[0040] The boom hoist winch 30 winds in and pays out the boom hoist rope 38. The boom hoist rope 38 is laid out so that this winding and paying out causes the mast 20 to rotate. Specifically, sheave blocks 40, 42, each with a plurality of 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 in and pays out the boom hoist rope 38, the distance between the two sheave blocks 40, 42 changes, which causes the mast 20 and, in turn, the boom 16, which is linked to it, to rotate in the hoisting direction.

[0041] The jib hoist winch 32 winds in and pays out the jib hoist rope 44, which is wound between the rear strut 21 and the front strut 22. The jib hoist rope 44 is arranged so that the winding and paying out of the rope rotates the front strut 22. Specifically, the jib hoist rope 44 pulled out from the jib hoist winch 32 is hooked around the idler sheave 32S and the intermediate boom sheave 46, and is further looped between the sheave blocks 47 and 48 multiple times. Therefore, by winding and paying out the jib hoist rope 44, the jib hoist winch 32 changes the distance between the sheave blocks 47 and 48, thereby rotating the front strut 22 relative to the rear strut 21. As a result, the jib hoist winch 32 raises and lowers the jib 18, which is linked to the front strut 22.

[0042] The main hoisting winch 34 hoists and lowers a load using a main hoisting rope 50. For this main hoisting, as described above, a rear strut idler sheave 52, a front strut idler sheave 53, and a main hoisting guide sheave 54 are rotatably mounted near the base end of the rear strut 21, near the base end of the front strut 22, and at the tip of the jib 18, respectively. Furthermore, 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 looped around the idler sheave 34S, the rear strut idler sheave 52, the front strut idler sheave 53, and the main hoisting guide sheave 54, in that order, and is stretched between the main hoisting point sheave 56 of the sheave block and a sheave 58 of a sheave block mounted on a main load hook 57. Therefore, when the main hoisting winch 34 winds in or pays out 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 jib 18 to be wound up or down. In this manner, in this embodiment, the main hoisting rope 50 (load rope) hangs down from the tip of the attachment 10S (hereinafter referred to as the attachment tip 10T) and is connected to the load via the main hook 57. In this way, the attachment tip 10T functions as a load support part that supports the load via the load rope.

[0043] Similarly, the auxiliary winch 36 hoists and lowers a load using an auxiliary hoisting rope 60. For this auxiliary hoisting, a rear strut idler sheave 62, a front strut idler sheave 63, and an auxiliary hoisting guide sheave 64 are rotatably mounted coaxially with the rear strut idler sheave 52, the front strut idler sheave 53, and the main hoisting guide sheave 54, respectively, 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 hung around the rear strut idler sheave 62, the front strut idler sheave 63, and the auxiliary hoisting guide sheave 64 in that order, and is suspended from the auxiliary hoisting point sheave. Therefore, when the auxiliary hoisting winch 36 winds or unwinds the auxiliary hoisting rope 60, an auxiliary hook (not shown) for the load connected to the end of the auxiliary hoisting rope 60 is hoisted or lowered.

[0044] [Hydraulic circuit configuration] FIG. 2 is a hydraulic circuit diagram of the swing drive unit 7S of the crane 10 according to this embodiment. FIG. 3 is a block diagram showing the configuration of a control system including a control device 80 according to this embodiment. The crane 10 has a swing drive unit 7S and a control device 80. The swing drive unit 7S is capable of swinging the upper swing structure 12 relative to the lower running structure 14 (swing operation). Furthermore, when the swing operation of the upper swing structure 12 of the crane 10 is performed, the control device 80 swings the upper swing structure 12 while limiting the swing angular velocity of the upper swing structure 12 so that an excessive lateral load acts on the attachment 10S (boom 16, jib 18).

[0045] 2, the swing drive unit 7S has an engine 70, a hydraulic pump 71 including a tilt adjustment unit 71S (FIG. 3), a swing motor 72, a control valve 73, a relief valve 74, an engine speed detection unit 75, a swing angular velocity detection unit 76, a first electromagnetic proportional valve 77, and a second electromagnetic proportional valve 78. The crane 10 also has a control device 80, an operation unit 81, and an input unit 82. Furthermore, referring to FIG. 3, the crane 10 also has a hoisting angle detection unit 66 and a weight detection unit 67.

[0046] The engine 70 has an output shaft connected to a hydraulic pump 71. The engine 70 drives the hydraulic pump 71 via the output shaft.

[0047] The hydraulic pump 71 is connected to the output shaft of the engine 70 and receives power input from the output shaft. The hydraulic pump 71 sucks in and discharges hydraulic oil from a tank to be supplied to the swing motor 72. The hydraulic pump 71 according to this embodiment is a variable displacement hydraulic pump, and the capacity (displacement volume) of the hydraulic pump 71 changes when a tilt command signal is input to a tilt adjustment unit 71S (regulator) included in the hydraulic pump 71. This changes the pump discharge flow rate, which is the flow rate of hydraulic oil discharged from the hydraulic pump 71. In other words, the hydraulic pump 71 is capable of receiving an input of a tilt command signal and changing the maximum discharge rate of hydraulic oil according to the magnitude of the tilt command signal. The tilt command signal is output from a swing control unit 803 (FIG. 3) of the control device 80, which will be described later.

[0048] The swing motor 72 is a hydraulic swing motor that drives the upper swing body 12 to swing. The swing motor 72 has multiple hydraulic chambers inside, and generates a driving force to swing the upper swing body 12 by receiving hydraulic oil supplied from the hydraulic pump 71 into one of the multiple hydraulic chambers and discharging hydraulic oil from the other hydraulic chambers. Specifically, the swing motor 72 is disposed between the upper swing body 12 and the lower traveling body 14 in FIG. 1 . The swing motor 72 has a motor shaft including a pinion and is fixed to the upper swing body 12. Meanwhile, the lower traveling body 14 has a circumferentially formed swing gear (not shown). The pinion of the swing motor 72 engages with the swing gear, causing the upper swing body 12 to swing in response to the rotation of the swing motor 72. For this reason, the swing motor 72 is disposed near the circumference of the swing gear. The swing motor 72 has a first motor port 72A and a second motor port 72B. The swing motor 72 receives hydraulic oil through the first motor port 72A to rotate the upper swing body 12 in a first direction (e.g., leftward) and discharges hydraulic oil through the second motor port 72B. On the other hand, the swing motor 72 receives hydraulic oil through the second motor port 72B to rotate the upper swing body 12 in a second direction (e.g., rightward) opposite to the first direction and discharges hydraulic oil through the first motor port 72A.

[0049] The control valve 73 is disposed in the hydraulic oil passage so as to be interposed between the hydraulic pump 71 and the swing motor 72. The control valve 73 operates to switch the direction of hydraulic oil supply from the hydraulic pump 71 to the swing motor 72 and to adjust the flow rate of the hydraulic oil. The control valve 73 is connected to a first motor port 72A and a second motor port 72B of the swing motor 72, respectively.

[0050] Control valve 73 operates to switch among a left turn position 73A, a neutral position 73B, and a right turn position 73C in response to a pilot pressure input to control valve 73. Control valve 73 has a pair of pilot ports, namely, a left turn pilot port 73P and a right turn pilot port 73Q. Control valve 73 is maintained in the neutral position 73B when no pilot pressure is input to either left turn pilot port 73P or right turn pilot port 73Q. Control valve 73 is switched to left turn position 73A when pilot pressure is input to left turn pilot port 73P, and is switched to right turn position 73C when pilot pressure is input to right turn pilot port 73Q. Control valve 73 opens with an opening area corresponding to the pilot pressure, changing the flow rate of hydraulic oil.

[0051] In the left turning position 73A, the control valve 73 supplies hydraulic oil discharged from the hydraulic pump 71 to the motor first port 72A and forms an oil passage that guides hydraulic oil discharged from the motor second port 72B to the tank. In the right turning position 73C, the control valve 73 supplies hydraulic oil discharged from the hydraulic pump 71 to the motor second port 72B and forms an oil passage that guides hydraulic oil discharged from the motor first port 72A to the tank. In addition, in the neutral position 73B, the control valve 73 allows hydraulic oil to circulate between the motor first port 72A and the motor second port 72B.

[0052] The relief valve 74 operates so that the pressure in the oil passage (bleed-off line) between the control valve 73 and the tank does not exceed a predetermined pressure.

[0053] The engine rotation speed detection unit 75 detects the rotation speed (or rotation number) of the output shaft of the engine 70. The swing angular velocity detection unit 76 detects the rotation speed (or rotation number) of the swing motor 72. In addition, the swing angular velocity detection unit 76 detects the rotation direction of the swing motor 72.

[0054] The operating unit 81 is disposed in the cab 15 (FIG. 1) and is operated by an operator to raise and lower the attachment 10S and to rotate the upper rotating body 12. The operating unit 81 related to the rotation operation of the upper rotating body 12 will be described below.

[0055] The operating unit 81 receives an operation for rotating the upper rotating body 12 relative to the lower traveling body 14, and outputs a rotation command signal corresponding to the magnitude of the operation, which is input to the control device 80. The operating unit 81 has an operating lever 81A and a remote control unit 81B. The operating lever 81A can be selectively operated to a first operating region for rotating the upper rotating body 12 in the first direction, a second operating region for rotating the upper rotating body 12 in the second direction, and a neutral operating region between the first operating region and the second operating region. The operating amount of the operating lever 81A in the first operating region and the second operating region is variable.

[0056] When the operator operates the operating lever 81A to the first operation range, the remote control unit 81B inputs a signal corresponding to the amount of operation received by the operating lever 81A to the control device 80. When the operator operates the operating lever 81A to the second operation range, the remote control unit 81B inputs a signal corresponding to the amount of operation received by the operating lever 81A to the control device 80. As a result, command signals are input from the control device 80 to the first solenoid proportional valve 77 and the second solenoid proportional valve 78.

[0057] The first solenoid proportional valve 77 and the second solenoid proportional valve 78 adjust the pilot pressure input to the control valve 73 in response to a command signal provided from a swing control unit 803 of the control device 80. Specifically, the first solenoid proportional valve 77 and the second solenoid proportional valve 78 are interposed between a pilot hydraulic source and a left swing pilot port 73P and a right swing pilot port 73Q of the control valve 73, and are connected to the left swing pilot port 73P and the right swing pilot port 73Q via pilot lines, respectively. When a command signal is provided from the swing control unit 803 (FIG. 3), the first solenoid proportional valve 77 opens to reduce the pilot pressure supplied to the left swing pilot port 73P. Furthermore, when a command signal is provided from the swing control unit 803, the second solenoid proportional valve 78 opens to reduce the pilot pressure supplied to the right swing pilot port 73Q. At this time, the stroke amount of the spool of the control valve 73 changes in response to changes in the pilot pressure input to the left swing pilot port 73P and the right swing pilot port 73Q. The swing control unit 803 then controls the drive of the swing motor 72 by changing the stroke amount of the spool of the control valve 73 to adjust the amount of hydraulic oil in each of the ports 72A, 72B of the swing motor 72.

[0058] The control valve 73, first solenoid proportional valve 77, and second solenoid proportional valve 78 constitute a flow rate adjustment mechanism 7T. The flow rate adjustment mechanism 7T adjusts the flow rate of hydraulic oil discharged from the hydraulic pump 71 and supplied to the swing motor 72 in response to a swing command signal output from the operation unit 81. The engine 70, hydraulic pump 71, swing motor 72, and flow rate adjustment mechanism 7T constitute the swing drive unit 7S. While FIG. 2 shows the hydraulic circuit related to the swing operation of the upper swing structure 12 of the crane 10, the crane 10 also has hydraulic circuits (not shown) related to the traveling operation of the lower running structure 14, the raising and lowering operation of the boom 16 and jib 18, and the winding up and lowering operation of the main hoisting rope 50 and the auxiliary hoisting rope 60. During the raising and lowering operation of the boom 16 and jib 18, the boom hoist winch 30 and the jib hoist winch 32 are each rotationally driven in response to an operation input to the operation unit 81. In addition, when the main hoisting rope 50 and the auxiliary hoisting rope 60 are being hoisted up and down, the main hoisting winch 34 and the auxiliary hoisting winch 36 are each rotationally driven in accordance with the operation input to the operating unit 81.

[0059] The input unit 82 accepts input of various information by an operator. The information input from the input unit 82 is stored (memorized) in a storage unit of the control device 80, which will be described later.

[0060] The hoisting angle detection unit 66 detects the hoisting angle of the attachment 10S, i.e., the angle relative to the ground. In this embodiment, the hoisting angle detection unit 66 is capable of detecting the hoisting angle (angle relative to the ground) of the boom 16 and the hoisting angle of the jib 18.

[0061] The weight detection unit 67 detects the weight of the load 100 connected to the main hoisting rope 50 (auxiliary hoisting rope 60). The weight detection unit 67 is composed of a tension sensor attached to the main hoisting winch 34 (auxiliary hoisting winch 36), etc.

[0062] The control device 80 comprehensively controls the operation of the crane 10, and is electrically connected to send and receive control signals to the operation unit 81, input unit 82, swing angular velocity detection unit 76, engine rotation speed detection unit 75, hoisting angle detection unit 66, weight detection unit 67, tilt adjustment unit 71S, first electromagnetic proportional valve 77, second electromagnetic proportional valve 78, etc. The control device 80 is also electrically connected to other units provided on the crane 10.

[0063] The control device 80 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores a control program, a RAM (Random Access Memory) that is used as the CPU's working area, etc., and when the CPU executes the control program, it operates to have the functions of a weight acquisition unit 800, an operating radius acquisition unit 801, a maximum angular velocity setting unit 802, a turning control unit 803, an alarm control unit 804, and a memory unit 810.

[0064] The weight acquisition unit 800 acquires the weight of the suspended load 100 detected by the weight detection unit 67.

[0065] The working radius acquisition unit 801 acquires the working radius of the crane 10 based on shape information of the attachment 10S (e.g., the lengths of the boom 16 and jib 18) and the hoisting angles of the boom 16 and jib 18 detected by the hoisting angle detection unit 66. Here, the working radius (FIG. 5A, described later) is the horizontal distance from the rotation axis CL of the upper rotating body 12 to the tip of the attachment 10T (an example of a load support portion) (i.e., the distance between the rotation axis CL and the tip of the attachment 10T in a plan view). The shape information of the attachment 10S is pre-stored in the storage unit 810 as part of the design information of the attachment 10S.

[0066] The maximum angular velocity setting unit 802 sets the maximum allowable angular velocity of the upper rotating body 12 so as to satisfy a predetermined acceleration condition that the lateral acceleration in the circumferential direction of the attachment tip portion 10T (FIG. 5B, described later) is equal to or less than the maximum allowable lateral acceleration in the circumferential direction allowed at the tip portion. Specifically, the maximum angular velocity setting unit 802 sets the maximum allowable angular velocity of the upper rotating body 12 according to the working radius based on a maximum allowable angular velocity map M1 (FIG. 6E, described later) that is preset so as to satisfy the predetermined acceleration condition.

[0067] The swing control unit 803 receives the swing command signal output from the operation unit 81 and controls the swing drive unit 7S so that the upper swing body 12 swings relative to the undercarriage 14 in response to the swing command signal. When accelerating and decelerating the upper swing body 12 in the circumferential direction, the swing control unit 803 controls the swing drive unit 7S so that the swing angular velocity of the upper swing body 12 is equal to or less than the maximum allowable angular velocity set by the maximum angular velocity setting unit 802 and so that the convergence time of the acceleration / deceleration operation is equal to or less than the convergence time specified in a convergence time map M2 ( FIG. 6C ), which will be described later. In this embodiment, the swing control unit 803 inputs a tilt command signal corresponding to the maximum allowable angular velocity set by the maximum angular velocity setting unit 802 to the hydraulic pump 71, thereby limiting the discharge amount of hydraulic oil discharged from the hydraulic pump 71 so that the swing angular velocity of the upper swing body 12 is equal to or less than the maximum allowable angular velocity.

[0068] The alarm control unit 804 determines whether the weight of the suspended load 100 acquired by the weight acquisition unit 800 exceeds a preset rated load, and if it determines that the weight exceeds the rated load, issues an alarm via an alarm device (e.g., a display) not shown. The alarm device is not limited to a display, and a speaker or the like may also be used. The rated load changes depending on the working radius, and a rated load map M0 (FIG. 4) that defines the relationship between the working radius and the rated load is stored in the memory unit 810 (described later). The alarm control unit 804 references this rated load map M0 to acquire the rated load corresponding to the current working radius, and performs the determination process by comparing the acquired rated load with the weight of the suspended load 100.

[0069] The storage unit 810 stores, as data, design information (including information on mass, dimensions, shape, etc.) of the attachment 10S referenced by the working radius acquisition unit 801, the rated load map M0 (FIG. 4), a maximum allowable angular velocity map M1 (FIG. 6E) referenced by the maximum angular velocity setting unit 802, and a convergence time map M2 (FIG. 6C) referenced by the swing control unit 803. The rated load map M0, maximum allowable angular velocity map M1, and convergence time map M2 will be described in detail later.

[0070] [About the load rating map] 4 is a diagram showing an example of a rated load map M0 stored in the storage unit 810. This rated load map M0 defines the relationship between the working radius of the crane 10 and the rated load.

[0071] As shown in this figure, the rated load of the crane 10 (line U0 shown by a thick solid line) is determined by the smaller of the strength allowable weight (line U1 shown by a dotted line), which is the maximum allowable weight of the load 100 set based on the strength limit of the attachment 10S, and the stable allowable weight (line U2 shown by a dashed line), which is the maximum allowable weight of the load 100 set based on the posture stability limit of the crane 10.

[0072] Here, the strength allowable weight is set so that the attachment 10S can withstand the strength when a lateral load (= W × X0 / 100) of a designed lateral load rate X0 [%] is applied to the load 100 in addition to the weight W [tf] of the load 100. On the other hand, the stable allowable weight is the maximum allowable weight of the load 100 that can maintain the posture stability of the crane 10, and is set, for example, based on the balance limit of the moment at which the crane 10 can perform work using the attachment 10S without tipping over.

[0073] Below, additional explanation will be provided to deepen understanding of the rated load, but this is for explanatory purposes only, and what is actually stored in the memory unit 810 is the data for the above-mentioned rated load (line U0 shown by the thick line in Figure 4), and other information is not essential information that should be included in the rated load map M0.

[0074] When the working radius at the intersection of the line U1 defining the strength allowable weight and the line U2 defining the stability allowable weight in the rated load map M0 (Fig. 4) is defined as R0 (hereinafter referred to as the predetermined working radius), in the first working radius region where the working radius is smaller than the predetermined working radius R0 (region where the working radius < R0), the rated load (capacity) of the crane 10 is determined by the strength limit of the attachment 10S (that is, the line U1 corresponding to the strength allowable weight). On the other hand, in the second working radius region where the working radius is larger than the predetermined working radius R0 (region where the working radius > R0), the rated load (capacity) of the crane 10 is determined by the attitude stability limit of the crane 10 (that is, the line U2 corresponding to the stability allowable weight). Note that at the position where the working radius is equal to the predetermined working radius R0, since the strength allowable weight and the stability allowable weight are equal, the rated load W0 of the crane 10 may be determined based on either the strength allowable weight or the stability allowable weight.

[0075] Here, in the second working radius region, as described above, the rated load (capacity) of the crane 10 is determined by the stability allowable weight, which is smaller than the strength allowable weight. Therefore, there is a margin in terms of strength compared to the first working radius region. Thus, when the allowable lateral load rate when setting the line U1 defining the strength allowable weight is X0%, at each working radius R1, R2 (in this example, R1 < R2) larger than the predetermined working radius R0 shown in Fig. 4, the rated loads W1, W2 are smaller than the strength allowable weight (line U1), so the allowable lateral load rate (the ratio of the maximum allowable lateral load in the circumferential direction to the rated load) increases accordingly. In Fig. 4, for comparison, the line K1 of the strength allowable weight corresponding to the allowable lateral load rate X1 (%) (> X0 (%)) at the working radius R1 and the line K2 of the strength allowable weight corresponding to the allowable lateral load rate X2% (> X1 (%)) at the working radius R2 are shown by dashed-dotted lines.

[0076] [Regarding the maximum allowable lateral acceleration and the maximum allowable angular velocity] Next, the maximum allowable lateral acceleration at the attachment tip 10T and the maximum allowable angular velocity of the upper rotating body 12 will be described with reference to Figures 5A to 5C. Figure 5A is a side view that schematically shows the crane 10, Figure 5B is a plan view that schematically shows the crane 10, and Figure 5C is a side view seen from the outside in the direction of the rotating radius that schematically shows a state in which a load 100 is supported on the attachment tip 10T via a load rope.

[0077] 5A to 5C, the upper rotating body 12 to which the attachment 10S of the crane 10 is attached is rotated about its rotation axis CL at a rotation angular acceleration dω / dt (rad / sec 2 In this case, if the working radius is R (m), the tip of the attachment 10T will have a lateral acceleration A (m / sec 2 ) occurs (FIGS. 5B and 5C). This lateral acceleration A is calculated by the following equation (1): A = R × dω / dt…(1)

[0078] Then, due to this lateral acceleration A in the circumferential direction, a circumferential inertial force F (N) acts on the suspended load 100. This inertial force F is calculated by the following equation (2) where M (kg) is the mass of the suspended load 100. F=M×A…………(2)

[0079] In this case, if the allowable lateral load rate that the attachment 10S can withstand in terms of strength is X (%) as described above, the maximum allowable circumferential lateral load Fmax (N) that is allowable at the tip of the attachment 10T when the upper rotating body 12 performs a rotating operation while suspending the load 100 can be calculated using the following equation (3). Fmax=M×g×X / 100…………(3)

[0080] On the other hand, since the inertial force F (N) due to the circumferential lateral acceleration A is calculated as M×a as described above, the maximum allowable lateral acceleration Amax for keeping the inertial force (F) generated by the rotation acceleration operation of the upper rotating body 12 below the allowable lateral load can be calculated using the following equation (4). Amax=g×X / 100…………(4)

[0081] As described above, the allowable lateral load rate in the first working radius range where the working radius is equal to or less than the predetermined working radius R0 is X0 (%), the allowable lateral load rate at the working radius R1 in the second working radius range is X1 (%), and the allowable lateral load rate at the working radius R2 is X2 (%). Therefore, when the relational expression (4) is used, the relationship between the working radius and the maximum allowable lateral acceleration Amax is as shown by the solid line in the graph of Figure 6A. The two-dot chain line in the graph indicates the conventional example.

[0082] When the upper rotating body 12 is accelerated and decelerated in the circumferential direction while maintaining this maximum allowable lateral acceleration Amax, and the convergence time from the start of each operation to the end of the operation is defined as T0 [s], the maximum allowable lateral speed Vmax, which is the maximum circumferential speed allowable at the tip end 10T of the attachment during the rotation of the upper rotating body 12, can be calculated using the following equation (5). Vmax=A×T0…………(5)

[0083] Figure 6B is a graph showing the relationship between the working radius and the maximum allowable lateral speed calculated based on equation (5). The two-dot chain line in the graph indicates the conventional example. V0, V1, and V2 are the maximum allowable lateral speeds when the working radii are R0, R1, and R2, respectively.

[0084] That is, when the working radius is R0, the maximum allowable lateral acceleration of the attachment tip 10T is A0 = g × X0 / 100 as described above, and the convergence time (acceleration / deceleration time) of the acceleration / deceleration operation at this time is T0. Based on equation (5), the maximum allowable lateral speed V0 at working radius R0 is calculated as V0 = A0 × T0. Similarly, when the working radius is R1, the maximum allowable lateral acceleration of the attachment tip 10T is A1 = g × X1 / 100, and the convergence time of the acceleration / deceleration operation at this time is T0. The maximum allowable lateral speed V1 at working radius R1 is calculated as V1 = A1 × T0. Furthermore, when the working radius is R2, the maximum allowable lateral acceleration of the attachment tip 10T is A2 = g × X2 / 100, and the convergence time of the acceleration / deceleration operation at this time is T0. The maximum allowable lateral speed V2 at working radius R2 is calculated as V2 = A2 × T0. Note that because the maximum allowable lateral acceleration A is expressed as an absolute value, the maximum allowable lateral acceleration during deceleration is -A in mathematical terms, but in this specification, "acceleration" refers to the absolute value regardless of its sign. This applies not only to lateral acceleration but also to angular acceleration.

[0085] The convergence time of the acceleration / deceleration operation is set in advance according to the working radius. The memory unit 810 stores a convergence time map M2 that defines the relationship between this convergence time and the working radius.

[0086] 6C is a graph showing an example of this convergence time map M2. The solid line in the graph represents this embodiment, and the two-dot chain line represents a conventional example. As shown in the figure, the convergence time is set to a constant value (=T0) regardless of the working radius.

[0087] Here, the braking distance L (the circumferential movement distance of the attachment tip 10T from the start to the end of the deceleration operation) associated with the deceleration operation in the circumferential direction (rotation direction) of the attachment 10S is calculated using the following equation (6). Note that, for simplicity, the swing of the suspended load 100 is ignored here. Figure 6D is a graph showing the calculation results of the braking distance L using the following equation (6), where the solid line indicates this embodiment and the two-dot chain line indicates a conventional example. L=1 / 2×V×T0…………(6)

[0088] Further, the maximum allowable angular velocity ωmax of the upper rotating body 12 for satisfying the above maximum allowable lateral velocity V is determined by the following equation (7). ωmax=V / R…………(7)

[0089] 6E shows a maximum allowable angular velocity map M1 that defines the relationship between the maximum allowable angular velocity ωmax of the upper rotating body 12 calculated using equation (7) and the working radius. This maximum allowable angular velocity map M1 is stored in the memory unit 810. Note that in FIG. 6E, this embodiment is shown by a solid line, and a conventional example is shown by a two-dot chain line for comparison. However, it is sufficient that the memory unit 810 stores at least the data for the line shown by the solid line according to this embodiment. According to this maximum allowable angular velocity map M1, the maximum allowable angular velocity corresponding to the predetermined working radius R0 is set to ω0, the maximum allowable angular velocity corresponding to the working radius R1 is set to ω1, and the maximum allowable angular velocity corresponding to the working radius R2 is set to ω2, satisfying the relationship ω0<ω1<ω2. As can be understood from the explanation so far, the maximum allowable angular velocity map M1 stored in the memory unit 810 is data that defines the maximum allowable angular velocity of the upper rotating body 12 according to the working radius so as to satisfy a predetermined acceleration condition that the circumferential lateral acceleration at the attachment tip 10T (load support part) is equal to or less than the maximum allowable lateral acceleration.

[0090] [Drive control of the swivel drive unit] Next, the drive control of the swivel drive unit 7S executed by the control device 80 will be described in detail with reference to the flowchart shown in FIG.

[0091] In step SA1, the rotation control unit 803 determines, based on the operation signal received from the operation unit 81, whether a rotation operation has been performed on the operation unit 81 to rotate the upper rotating body 12, and if the determination is NO, it returns, while if the determination is YES, it proceeds to step SA2.

[0092] In step SA2, the weight acquisition unit 800 acquires the weight of the suspended load 100 detected by the weight detection unit 67.

[0093] In step SA3, the working radius acquisition unit 801 acquires the working radius of the crane 10 based on the shape information of the attachment 10S and the hoisting angles of the boom 16 and jib 18 detected by the hoisting angle detection unit 66.

[0094] In step SA4, the alarm control unit 804 acquires the rated load corresponding to the working radius acquired in step SA2 based on the rated load map (rated line U0 in FIG. 4) stored in the memory unit 810. Then, the alarm control unit 804 determines whether the weight of the suspended load 100 acquired in step SA1 is equal to or less than the rated load, and if the determination is NO, proceeds to step SA8 and returns to step SA1 where the above-mentioned alarm processing is executed, while if the determination is YES, proceeds to step SA5. Note that in step SA8, prohibition processing may be executed in conjunction with the above-mentioned alarm processing to prohibit the rotation operation of the upper rotating body 12.

[0095] In step SA5, the maximum angular velocity setting unit 802 sets the maximum allowable angular velocity of the upper rotating body 12 corresponding to the working radius obtained in step SA2 based on the maximum allowable angular velocity map M1 (Figure 6E) stored in the memory unit 810.

[0096] In step SA6, the turning control unit 803 sets the convergence time corresponding to the working radius acquired in step SA2 as the target convergence time based on the convergence time map (FIG. 6C) stored in the storage unit 810.

[0097] In step SA7, the swing control unit 803 drives the swing drive unit 7S in accordance with the operation (amount and direction of operation) of the operation unit 81 so that the swing angular velocity of the upper swing body 12 is equal to or less than the maximum allowable angular velocity, based on the maximum allowable angular velocity of the upper swing body 12 acquired in step SA4 and the target convergence time set in step SA5. After completion of this step SA7, the process returns to step SA1.

[0098] Then, the control device 80 drives the rotation drive unit 7S in response to the operation of the operation unit 81 by repeating the processes of steps SA1 to SA8, and controls the rotation operation of the upper rotating body 12.

[0099] Figure 8A is a time chart showing an example of a velocity profile of the rotation angular velocity when the control device 80 controls the rotation of the upper rotating body 12, and Figure 8B is a time chart showing the change over time in the rotation angular acceleration of the upper rotating body 12 corresponding to the velocity profile of Figure 8A.

[0100] As an example, Figure 8A shows speed profiles corresponding to a case where a full operation is performed on the operating unit 81, in which the operation amount is the maximum, and a case where a non-full operation is performed, in which the operation amount is smaller than the full operation (the operation amount is smaller than the maximum operation amount) (in Figure 8A, a half operation, in which the operation amount is half).

[0101] In this embodiment, when the operating unit 81 is fully operated, the rotation control unit 803 drives the rotation drive unit 7S so that the rotation angular velocity of the upper rotating body 12 (the rotation angular velocity in a steady state after acceleration is completed) becomes the maximum allowable angular velocity (ωmax in FIG. 8A), and when the operating unit 81 is not fully operated (an operation in which the operation amount is smaller than full operation and larger than 0), the rotation control unit 803 drives the rotation drive unit 7S so as to rotate the upper rotating body 12 at a rotation angular velocity proportional to the operation amount of the operating unit 81, with this maximum angular velocity as a reference. Therefore, for example, when the operating unit 81 is half operated (an example of not full operation), as shown in FIG. 8A, the upper rotating body 12 rotates at a rotation angular velocity ωhalf that is half the maximum allowable angular velocity ωmax set by the maximum angular velocity setting unit 802. Furthermore, as shown in FIG. 8B, when the operating unit 81 is half-operated, the turning angular acceleration B1 during acceleration and deceleration is reduced to half of the turning acceleration B2 during full operation.

[0102] 9 is a time chart for explaining an example of drive control of the swing drive unit 7S by the swing control unit 803. The upper part of FIG. 9 shows the operation amount of the operation unit 81, the middle part shows the secondary pressure of the electromagnetic proportional valves 77 and 78 that make up the swing drive unit 7S, and the lower part shows the pump capacity of the hydraulic pump 71.

[0103] 9, the swing control unit 803 controls the swing motor 72 (torque output device in the swing drive unit 7S) by controlling the secondary pressure of the electromagnetic proportional valves 77, 78 and the pump capacity of the hydraulic pump 71. Specifically, the swing control unit 803 first acquires a convergence time corresponding to the current working radius of the crane 10 (step SA6 described above), sets this acquired convergence time as the rise time and fall time of the secondary pressure and the increase time and decrease time of the pump capacity, and calculates the discharge flow rate q1 of the hydraulic pump 71 by the following equation (8) so that the swing angular velocity of the upper swing body 12 when the operation unit 81 is fully operated becomes the maximum allowable angular velocity. q1=qm×(ωmax×N) / NP…………(8) Here, qm is the displacement of the hydraulic motor, ωmax is the maximum allowable angular velocity, N is the reduction ratio of the swing motor 72, and NP is the pump rotation speed of the hydraulic pump 71. This pump rotation speed NP may be calculated by multiplying the engine rotation speed detected by the engine rotation speed detection unit 75 by a predetermined reduction ratio, or may be detected by a rotation speed detection sensor provided in the hydraulic pump 71.

[0104] The swing control unit 803 controls a tilt command signal to a tilt adjustment unit 71S (regulator) of the hydraulic pump 71 so as to control the discharge flow rate of the hydraulic pump 71 to the calculated discharge flow rate q1.

[0105] 9 shows an example in which the operation amount of the operation unit 81 increases from 0 to the full operation amount (FULL) in one go, that is, a case in which the operation unit 81 is suddenly operated. However, even if a gentle operation is performed so that the operation amount of the operation unit 81 gradually increases to the full operation amount, the same convergence time is set as in the case in which a sudden operation is performed. That is, in this example, the turning control unit 803 maintains the convergence time at a constant value (= T0) regardless of the operation speed of the operation unit 81. Furthermore, in this embodiment, the turning control unit 803 maintains the convergence time at a constant value (= T0) regardless of the magnitude of the operation amount of the operation unit 81.

[0106] As described above, in this embodiment, when the slewing drive unit 7S accelerates and decelerates the upper slewing body 12 in the circumferential direction around the slewing axis CL, the slewing control unit 803 is configured to perform drive control of the slewing drive unit 7S so as to satisfy a predetermined acceleration condition in which the circumferential lateral acceleration of the attachment tip 10T (an example of a load support part) of the upper slewing body 12 is equal to or less than the maximum allowable circumferential lateral acceleration of the attachment tip 10T, which is determined according to the working radius.

[0107] Here, as explained in Figure 4, in a first working radius region where the strength allowable weight, which is the maximum allowable weight of the load 100 set based on the strength limit of the attachment 10S, is equal to the stable allowable weight, which is the maximum allowable weight of the load 100 set based on the posture stability limit of the attachment 10S, and where the strength allowable weight is smaller than the stable allowable weight, the maximum allowable lateral acceleration is set based on the ratio of the maximum allowable lateral load in the circumferential direction of the attachment tip 10T to the strength allowable weight (i.e., the allowable lateral load rate X0 (%)), while in a second working radius region where the working radius is larger than the predetermined working radius R0 and where the stable allowable weight is smaller than the strength allowable weight, the maximum allowable lateral acceleration is set based on the ratio of the maximum allowable lateral load in the circumferential direction of the attachment tip 10T to the stable allowable weight (the allowable lateral load rates X1 and X2 (%) in the above example, etc.).

[0108] According to this, in both the first and second working radius ranges, the maximum allowable lateral acceleration of the attachment tip 10T (load support part) is set based on the ratio (allowable lateral load rate) of the maximum allowable lateral load to the smaller of the strength allowable weight and the stability allowable weight, which limit the weight of the load 100. Therefore, compared to setting the maximum allowable lateral acceleration based on, for example, the ratio to the larger of the strength allowable weight and the stability allowable weight, the maximum allowable lateral acceleration of the attachment tip 10T can be increased by the amount corresponding to the lighter maximum allowable weight of the reference load 100. When the maximum allowable lateral acceleration of the attachment tip 10T is increased, the rotation angular acceleration of the upper rotating body 12 can be increased accordingly during acceleration and deceleration of the upper rotating body 12, thereby preventing an unnecessary decrease in the rotation angular acceleration of the upper rotating body 12 in the circumferential direction caused by the rotation drive unit 7S. This in turn prevents a loss of speed in work performed by the attachment 10S.

[0109] Explaining this point in comparison with a conventional example with reference to Figure 6E, in the conventional example, the maximum allowable lateral acceleration (= Amax) of the attachment tip 10T is constant (= g × X0 / 100) regardless of the working radius, and therefore the maximum allowable lateral velocity (= Vmax) is also constant regardless of the working radius according to the relationship in equation (5). In this case, according to the relationship in equation (7), if the maximum allowable lateral velocity (= Vmax) is constant, the maximum allowable angular velocity (= ωmax) will decrease as the working radius R increases due to a so-called hyperbolic relationship, as shown by the two-dot chain line in Figure 6E.

[0110] In contrast, in this embodiment, in the second working radius region where the working radius is greater than the predetermined working radius R0 (i.e., the region where the stable allowable weight is smaller than the strength allowable weight), the maximum allowable angular velocity of the upper rotating body 12 increases as the working radius increases due to the relationship between equations (5) and (7) ( FIG. 6E ). Therefore, in the second working radius region, the swing angular velocity of the upper rotating body 12 can be set higher than in the conventional example while ensuring safety in terms of strength of the attachment 10S. Therefore, the workability (working speed) of the attachment 10S can be improved while ensuring safety in terms of strength.

[0111] (Embodiment 2) 10A to 10E are diagrams corresponding to FIGS. 6A to 6E and show embodiment 2. This embodiment differs from embodiment 1 in that the convergence time of the upper rotating body 12 is changed according to the working radius of the crane 10. For comparison, in FIGS. 10A to 10E, the line corresponding to the conventional example is shown by a two-dot chain line, the line corresponding to embodiment 1 is shown by a dashed line, and the line corresponding to this embodiment is shown by a solid line.

[0112] That is, in the first embodiment, the convergence time is constant regardless of the working radius as shown in Figure 6C, whereas in this embodiment, as shown in the convergence time map M2 in Figure 10C, in the second working radius region where the working radius exceeds the predetermined working radius R0, the convergence time decreases as the working radius increases.

[0113] Therefore, in the control device 80 of the crane 10 of this embodiment, in the second working radius region where the working radius is larger than the predetermined working radius R0, the convergence time of the acceleration / deceleration operation is shorter than in the first embodiment, and therefore, from equation (5), the maximum allowable lateral speed of the attachment tip portion 10T (FIG. 10B) is lower than in the first embodiment but is higher than in the conventional example. Furthermore, since both the maximum allowable lateral speed and the convergence time are lower than in the first embodiment, from equation (6), the braking distance of the attachment tip portion 10T is shorter than in the first embodiment (FIG. 10D). Note that in this embodiment, as an example, the maximum allowable lateral speed of the attachment tip portion 10T is increased compared to the conventional example, while the braking distance is set to the same value as in the conventional example (FIGS. 10B and 10D).

[0114] Therefore, the maximum allowable lateral speed can be increased without increasing the braking distance compared to the conventional example, thereby improving the workability (work speed) of the attachment 10S.

[0115] As described above, in this embodiment 2, in the second working radius region where the working radius is larger than the predetermined working radius R0, the slewing control unit 803 is configured to perform drive control of the slewing drive unit 7S so as to reduce the convergence time, which is the time from the start to the end of the operation when the slewing drive unit 7S accelerates and decelerates the upper slewing body 12 in the circumferential direction, the larger the working radius acquired by the working radius acquisition unit 801.Therefore, compared to the conventional example, the maximum allowable lateral speed can be increased without increasing the braking distance, thereby improving the workability (working speed) of the attachment 10S.

[0116] (Embodiment 3) 11A and 11B are views corresponding to FIGS. 8A and 8B showing embodiment 3. This embodiment differs from the above-described embodiments in that the convergence time of the deceleration operation of the upper rotating body 12 is changed depending on the amount of operation of the operation unit 81.

[0117] That is, in this embodiment, the rotation control unit 803 determines whether a full operation has been performed on the operation unit 81 based on a signal from the operation unit 81, and if it determines that a full operation has been performed, it performs an acceleration operation of the upper rotating body 12 so that the upper rotating body 12 rotates at the maximum allowable angular velocity ωmax in a steady state, as shown by the solid line in Figure 11A, and when the operation is released, it drives the rotation drive unit 7S so that the upper rotating body 12 performs a deceleration operation until it stops rotating.

[0118] On the other hand, when the swing control unit 803 determines, based on a signal from the operation unit 81, that a non-full operation (an operation in which the amount of operation is smaller than the maximum amount of operation) has been performed on the operation unit 81, it operates the swing drive unit 7S to swing the upper swing body 12 at a swing angular velocity smaller than the maximum allowable angular velocity ωmax (=ωmax × actual amount of operation / full amount of operation, and in FIG. 11A shows ωhalf corresponding to half operation) in proportion to the amount of operation, and when the operation is released, it operates the swing drive unit 7S to decelerate the upper swing body 12 until it stops swinging. At this time, the swing control unit 803 is configured to set a convergence time T1 during the deceleration operation so that the swing angular acceleration of the upper swing body 12 during this deceleration operation becomes equal to that during the full operation.

[0119] 11A, the convergence time T1 during the deceleration operation is set so that the rate of change (corresponding to the slope of the straight line in the graph) of the time change in the swing angular velocity during the deceleration operation of the upper swing body 12 becomes equal to that during full operation. Specifically, the convergence time T1 is calculated by the following equation (9). T1=T0×ωn / ωmax …………(9) Here, ωn is the rotation angular velocity of the upper rotating body 12. This rotation angular velocity ωn may be detected based on the rotation speed of the rotation motor 72 detected by the rotation angular velocity detection unit 76, for example, or may be calculated (estimated) based on the operation amount of the operation unit 81.

[0120] As described above, in this embodiment 3, the crane 10 is provided with an operation unit 81 that receives operations for rotating the upper rotating body 12 and outputs the operation signal, and the rotation control unit 803 is configured to reduce the convergence time, which is the time from the start of the operation to the end of the operation, when a non-full operation, which is an operation amount smaller than a full operation, is performed on the operation unit 81, so that the rotation angular acceleration when decelerating the upper rotating body 12 in the circumferential direction does not change, compared to when the full operation is performed.

[0121] According to this, when the upper rotating body 12 decelerates as a result of releasing a non-full operation of the operating unit 81 after the operation has been performed, the convergence time is reduced (reduced from T0 to T1) compared to when a full operation is performed, thereby reducing the braking distance of the attachment tip 10T. Furthermore, because the swing angular acceleration (the rate of change of the swing angular velocity during deceleration, which is the slope of the line on the graph) during the deceleration of the upper rotating body 12 is maintained constant, the inertial force acting on the attachment tip 10T during the deceleration of the upper rotating body 12 does not change (increase) compared to when the upper rotating body 12 is fully operated. Therefore, the braking distance can be reduced while maintaining strength and safety compared to when the attachment 10S is fully operated, thereby improving the stopping position accuracy.

[0122] 12A and 12B, when a non-full operation is performed on the operating unit 81, the convergence time may be reduced from T0 to T1 not only during deceleration but also during acceleration. In this case, the convergence time is reduced not only during deceleration but also during acceleration, improving the workability (work speed) of the attachment 10S. Furthermore, although not shown, the convergence time may be reduced from T0 to T1 only during acceleration.

[0123] (Embodiment 4) Fig. 13 is a diagram equivalent to Fig. 7 and shows a fourth embodiment. This fourth embodiment differs from the above-described embodiments in that a correction process (the process of step SB7 described later) of the control parameters is executed when driving the upper rotating body 12 in accordance with the weight of the suspended load 100. Note that the processes of steps SB1 to SB6 and steps SB8 and SB9 in Fig. 13 are similar to the processes of steps SA1 to SA6 and steps SA7 and SA8 in the first embodiment, and therefore their description will be omitted as appropriate.

[0124] Specifically, in this embodiment, when the weight of the load 100 suspended by the crane 10 is smaller than the rated load, the maximum allowable lateral acceleration increases by the ratio of the weight of the load 100 to the rated load compared to when the weight of the load 100 is equal to the rated load. In step S7, the control parameters are corrected so as to satisfy this increased maximum allowable lateral acceleration.

[0125] That is, when the weight of the suspended load 100 is smaller than the rated load, the lateral load (inertial force) acting on the attachment tip 10T during the rotation of the upper rotating body 12 is smaller than when the weight of the suspended load 100 is the rated load, creating a margin in terms of strength. Therefore, the maximum allowable angular velocity of the upper rotating body 12 can be set higher by the amount of this margin in strength.

[0126] From a mechanical perspective, the allowable lateral load at the tip of the attachment 10T is the same when the weight of the suspended load 100 is the rated load and when it is less than the rated load, so the following equation (10) holds true.

[0127] M0×g×X0 / 100=M1×g×(X10) / 100…………(10) Where, M0: Mass of rated load M1: Mass of the suspended load that is lighter than the rated load X0: Allowable lateral load rate corresponding to the rated load X10: Allowable lateral load rate for a load that is lighter than the rated load

[0128] By rearranging the above equation (10), the relationship of the following equation (11) is derived. X10 = X0 × M0 / M1 …………(11) In this case, since M0>M1, the relationship X10>X0 is derived from equation (11).

[0129] Here, the maximum allowable lateral acceleration when the weight of the suspended load 100 is less than the rated load is g × X10 / 100 according to the above formula (4), which is increased by M0 / M1 times compared to the maximum allowable lateral acceleration of g × X0 / 100 when the load is the rated load (in other words, it increases by the ratio between the weight of the suspended load 100 and the rated load).

[0130] Therefore, in this embodiment, in step SB7 (FIG. 12), the turning control section 803 corrects the target convergence time T0 set based on the convergence time map based on the following equation (12). T0'=T0×M1 / M0…………(12)

[0131] Thus, the convergence time during acceleration / deceleration of the upper rotating body 12 is reduced from T0 to T0', thereby improving the workability of the attachment 10S. Furthermore, the convergence time during deceleration of the upper rotating body 12 is reduced from T0 to T0', thereby reducing the braking distance of the attachment tip 10T during deceleration of the upper rotating body 12, thereby improving the stopping position accuracy of the attachment 10S.

[0132] As a modification of this embodiment 4, when the weight of the suspended load 100 is smaller than the rated load, instead of correcting the convergence time of the acceleration / deceleration operation of the upper rotating body 12, the maximum allowable angular velocity may be corrected using the following equation (13).

[0133] ω1=ω0×M0 / M1…………(13) ω1: Maximum allowable angular velocity when the weight of the suspended load is less than the rated load ω0: Maximum allowable angular velocity when the weight of the suspended load is the rated load

[0134] This correction process can increase the rotation angular velocity of the upper rotating body 12, thereby improving the workability of the attachment 10S.

[0135] As described above, in the fourth embodiment, the maximum allowable lateral acceleration of the attachment tip 10T is set to be higher by the ratio between the weight of the load 100 and the rated load when the weight of the load 100 is less than the rated load, compared to when the weight of the load 100 is equal to the rated load, and the slewing control unit 803 is configured to acquire the rated load of the load 100 corresponding to the working radius based on the working radius acquired by the working radius acquisition unit 801, and to execute drive control of the slewing drive unit 7S so as to satisfy the predetermined acceleration condition based on the ratio (=M0 / M1) between the acquired rated load and the weight of the load 100 acquired by the weight acquisition unit 800. Therefore, when the weight of the load 100 is less than the rated load, the maximum allowable angular velocity of the upper rotating body 12 is increased accordingly, thereby improving the workability (working speed) of the attachment 10S.

[0136] (Embodiment 5) 14 is a diagram equivalent to FIG. 3 showing embodiment 5. This embodiment 5 differs from the above-described embodiments in that the limit angular acceleration of the rotation drive unit 7S is calculated based on the total moment of inertia I0 of the group of rotating objects acquired by the moment of inertia acquisition unit 805, and the rotation angular velocity of the upper rotating body 12 is limited using this limit angular acceleration as an upper limit value.

[0137] That is, in this embodiment, the control device 80 further includes an inertia moment acquisition unit 805 as a functional unit.

[0138] The moment of inertia acquisition unit 805 first acquires (calculates) the total moment of inertia I0 of the group of rotating objects rotating around the rotation axis CL. In this example, the group of rotating objects consists of the upper rotating body 12, the attachment 10S, and the suspended load 100. The total moment of inertia I0 is the sum of the moment of inertia I1 of the upper rotating body 12, the moment of inertia I2 of the attachment 10S, and the moment of inertia I3 of the suspended load 100. The moment of inertia acquisition unit 805 calculates each of the moments of inertia I1 to I3 as follows:

[0139] The moment of inertia acquisition unit 805 calculates the moment of inertia I1 of the upper rotating body 12 based on design information (information on mass, dimensions, shape, etc.) of the upper rotating body 12. Note that since the moment of inertia I1 of the upper rotating body 12 is constant regardless of the working radius, it may be stored in advance in the storage unit 810.

[0140] In addition, the inertia moment acquisition unit 805 acquires posture information of the attachment 10S based on the elevation angles of the boom 16 and jib 18 detected by the elevation angle detection unit 66, and calculates the inertia moment I2 of the attachment 10S based on the acquired posture information and the design information of the attachment (information such as mass, dimensions, and shape) stored in the memory unit 810.

[0141] In addition, the inertia moment acquisition unit 805 calculates the inertia moment I3 of the suspended load 100 based on the working radius acquired by the working radius acquisition unit 801 and the weight of the suspended load 100 detected by the weight detection unit 67.

[0142] Then, the inertia moment obtaining unit 805 obtains (calculates) the total inertia moment I0 by adding up the three calculated inertia moments I1, I2, and I3.

[0143] Here, the limit angular acceleration of the upper rotating body 12, which is determined from the capacity (maximum output torque) of the rotating drive unit 7S, is calculated by the following equation (14). (dω / dt) limit =Tqmax / I0…………(14) Here, Tqmax is the maximum value of the swing torque that the swing drive unit 7S can output, and I0 is the total moment of inertia described above.

[0144] 15, the limit angular acceleration defined by equation (14) is shown by a solid line in a graph with the total moment of inertia on the horizontal axis and the swing angular acceleration on the vertical axis. As can be seen from this graph, the limit angular acceleration of the upper swing body 12 decreases as the total moment of inertia I0 increases.

[0145] On the other hand, the maximum allowable angular acceleration of the upper rotating body 12 that satisfies the predetermined acceleration condition is calculated, for example, by dividing the maximum allowable angular velocity of the upper rotating body 12 set by the maximum angular velocity setting unit 802 by the convergence time defined in the convergence time map. In Figure 14, the line indicating this maximum allowable angular acceleration is shown by a dashed line. Note that the line indicating the maximum allowable angular velocity is not actually such a simple straight line, but is shown here in a simplified manner.

[0146] The slewing control unit 803 calculates the total moment of inertia as a threshold moment of inertia It such that the limit angular acceleration determined based on the equation (14) is equal to the maximum allowable angular acceleration, and if the current total moment of inertia is equal to or less than the threshold moment of inertia It (i.e., if the maximum allowable angular acceleration is equal to or less than the limit angular acceleration), it executes drive control of the slewing drive unit 7S (control based on the maximum allowable angular velocity map M1 and convergence time map M2 described above) so that the slewing angular acceleration of the upper slewing body 12 is equal to or less than the maximum allowable angular acceleration set by the maximum angular velocity setting unit 802, while if the current moment of inertia is greater than the threshold moment of inertia It (i.e., if the limit angular acceleration is smaller than the maximum allowable angular acceleration), it executes drive control of the slewing drive unit 7S so that the slewing angular acceleration of the upper slewing body 12 is equal to or less than the limit angular acceleration.

[0147] According to this configuration, when the limit angular velocity is smaller than the maximum allowable angular acceleration of the upper rotating body 12, there is no need to perform control processing (calculation) based on the above-mentioned maximum allowable angular velocity map M1 and convergence time map M2, thereby reducing the calculation burden on the control device 80 and improving the processing speed.

[0148] (Embodiment 6) Next, a sixth embodiment will be described. In this embodiment, the control device 80 differs from the above-described embodiments in that it automatically controls the crane 10 based on an automatic operation program stored in advance in a ROM, and although not shown, the present embodiment does not include an operation unit 81 as in the above-described embodiments. In this embodiment, when the automatic operation control is performed, the swing control unit 803 controls the start timing of the deceleration operation of the upper swing body 12 when the upper swing body 12 is decelerated by the swing drive unit 7S, in the following procedure.

[0149] That is, when the upper rotating body 12 is decelerated, the swing control unit 803 executes a first calculation process to calculate, as a target convergence time, a convergence time of the deceleration operation when the upper rotating body 12 is decelerated at a maximum allowable angular acceleration that satisfies the predetermined acceleration condition (the maximum allowable angular velocity set by the maximum angular velocity setting unit 802). Specifically, the swing control unit 803 acquires, as the target convergence time, a convergence time corresponding to the current working radius based on a convergence time map M2 (see FIG. 6C, etc.) stored in the memory unit 810.

[0150] Next, the rotation control unit 803 executes a second calculation process in which, when the circumferential rotation angle of the upper rotating body 12 at the current time is θs and the rotation angular velocity of the upper rotating body 12 at the current time is ωs, the convergence time for starting the deceleration operation from the current time and stopping the upper rotating body 12 at a predetermined target rotation angle θt is calculated as a predicted convergence time Td using the following equation (15): Td=2×(θt-θs) / ωs………(15) Here, the turning angle θs can be detected by a sensor such as a rotary encoder, etc. Furthermore, the turning angular velocity ωs can be calculated by multiplying the turning angular velocity of the turning motor 72 detected by the turning angular velocity detection unit 76 by a predetermined deceleration ratio, for example.

[0151] Then, when the predicted convergence time Td matches the target convergence time, the swing control unit 803 executes drive control of the swing drive unit 7S to start the deceleration operation of the upper swing body 12. On the other hand, when the predicted convergence time Td does not match the target convergence time, the swing control unit 803 continues the swing operation of the upper swing body 12 by the swing drive unit 7S.

[0152] As described above, in this embodiment, when stopping the upper rotating body 12, the rotation control unit 803 controls the rotation drive unit 7S to start the deceleration operation of the upper rotating body 12 at a timing that satisfies the above-mentioned formula (16). Therefore, the upper rotating body 12 can be stopped at the predetermined target rotation angle θt while decelerating at the maximum allowable angular acceleration that satisfies the above-mentioned predetermined acceleration condition. Therefore, the upper rotating body 12 can be stopped accurately at the stop position while ensuring safety in terms of strength.

[0153] (Embodiment 7) Figure 16 is a view showing embodiment 7, which corresponds to Figure 3. This embodiment differs from the above-described embodiments in that a control device 80 is connected to an emergency stop operation unit 83 so as to be able to send and receive signals.

[0154] The emergency stop operation unit 83 outputs an emergency stop signal for bringing the upper rotating body 12 to an emergency stop when a predetermined operation (for example, a pressing operation) is performed by the operator while the upper rotating body 12 is rotating.

[0155] When the swing control unit 803 receives an emergency stop signal from the emergency stop operation unit 83, it causes the swing drive unit 7S to decelerate the upper swing body 12. Specifically, when the swing control unit 803 receives an emergency stop signal from the emergency stop operation unit 83, it stops the engine 70 (shown only in FIG. 2), and sets a convergence time required for the deceleration of the upper swing body 12 (deceleration time for decelerating the upper swing body 12 at the maximum allowable angular acceleration that satisfies the predetermined acceleration condition) based on the convergence time map M2 in accordance with the time chart shown in FIG. 9, and reduces the secondary pressure of the solenoid proportional valves 77, 78 to transition the control valve 73 from an open state to a closed state within the set convergence time.

[0156] According to this configuration, even when the emergency stop operating unit 83 is operated, the upper rotating body 12 is not immediately stopped by the rotation drive unit 7S, but the upper rotating body 12 is stopped while ensuring a convergence time (T0 in Figure 9) for decelerating the upper rotating body 12 at the maximum allowable angular acceleration that satisfies the specified acceleration condition. This allows the upper rotating body 12 to be stopped quickly without damaging the attachment 10S due to the lateral load of the suspended load 100 that occurs when the upper rotating body 12 decelerates.

[0157] When the emergency stop operation unit 83 is operated, the engine 70 stops as described above, and the rotation of the hydraulic pump 71 connected to the engine 70 also stops. The flow rate of hydraulic oil supplied from the hydraulic pump 71 becomes zero. However, this does not immediately stop the rotation of the swing motor 72; the swing motor 72 continues to swing due to its swing inertia force. While the swing motor 72 continues to swing, the control valve 73 is transitioned from the open state to the closed state for the convergence time set as described above. This causes the hydraulic oil discharged from the swing motor 72 to be throttled by the control valve 73, thereby slowing down the swing motor 72. As a result, the swing operation of the swing motor 72 stops for the convergence time. Stopping the engine 70 also stops the hydraulic pump 71, which supplies primary pressure to the electromagnetic proportional valves 77, 78. However, an accumulator may be separately installed as a pressure source that supplies primary pressure to the electromagnetic proportional valves 77, 78 during the convergence time set as described above.

[0158] (Other embodiments) The control device 80 for the crane 10 according to the embodiment of the present invention has been described above, but the present invention is not limited to this, and for example, the following modified embodiments can be adopted.

[0159] (1) That is, in each of the above-described embodiments, the maximum allowable angular velocity of the upper rotating body 12 is set in the maximum angular velocity setting unit 802 so as to satisfy the predetermined acceleration condition, and the upper rotating body 12 is controlled to rotate at or below this maximum allowable angular velocity by controlling the angular velocity during steady rotation and the convergence time during acceleration / deceleration operations as control target values. However, this is not limited to this, and for example, a maximum allowable angular acceleration of the upper rotating body 12 may be set so as to satisfy the predetermined acceleration condition, and rate limiter control may be executed to control the increase or decrease in the angular velocity of the upper rotating body 12 per unit time so that the absolute value of the increase or decrease in the angular velocity of the upper rotating body 12 per unit time is equal to or less than this maximum allowable angular acceleration.

[0160] Specifically, the increase q of the pump displacement per unit time may be controlled so as not to exceed a set value determined by the following equation (16), or the increase and / or decrease per unit time of the command signal (e.g., command current value) of the electromagnetic proportional valves 77, 78 may be controlled so as to be equal to or less than a set value. This set value may be, for example, a value obtained by dividing the maximum command signal of each electromagnetic proportional valve 77, 78 by the set convergence time. q=qm×(dω / dt)×N / NP…………(16) Here, qm is the displacement of the hydraulic motor, dω / dt is the swing angular acceleration, N is the reduction ratio of the swing motor 72, and NP is the pump rotation speed of the hydraulic pump 71.

[0161] Furthermore, the swing angular acceleration may be directly controlled by controlling the pressure by attaching a variable relief valve or the like to the hydraulic circuit. The relationship shown in the following equation (17) holds between the swing angular acceleration (= dω / dt) and the pressure P. For this reason, for example, the swing acceleration dω / dt of the upper swing body 12 may be controlled to be equal to or less than the maximum allowable angular acceleration by detecting the total moment of inertia I0 described above, calculating the target pressure P according to the relationship shown in the following equation (17), and controlling the pressure in the hydraulic circuit to reach the target pressure P using a variable relief valve or the like. I0×(dω / dt)=P×q / 2π…………(17)

[0162] (2) Furthermore, when controlling the amount of increase or decrease per unit time of the swing angular velocity of the upper swing body 12 in this way (when executing rate limiter control), the maximum value of the swing angular velocity of the upper swing body 12 may be limited. That is, if the amount of increase or decrease per unit time of the swing angular velocity is limited, there is a risk that the convergence time (acceleration / deceleration time) of the acceleration / deceleration operation of the upper swing body 12 will increase. In particular, if the convergence time (deceleration time) of the deceleration operation increases, there is a problem that the braking distance of the attachment tip 10T will increase. However, by limiting the maximum value of the swing angular velocity as described above, it is possible to avoid the problem of an increase in the braking distance.

[0163] (3) In each of the above embodiments, the convergence time (acceleration time) of the acceleration operation of the upper rotating body 12 and the convergence time (deceleration time) of the deceleration operation do not necessarily have to be the same, and may be different. By making the acceleration time longer than the deceleration time, the acceleration operation becomes gentler, improving fine operability, and by shortening the deceleration time, the braking distance of the attachment tip 10T can be reduced. In each of the above embodiments, the limit value when executing the rate limiter control may be different between the acceleration operation and the deceleration operation.

[0164] (4) In each of the above embodiments, the crane 10 includes the swing motor 72, which is a variable displacement hydraulic motor, the hydraulic pump 71 that discharges hydraulic oil to the swing motor 72, a hydraulic circuit that connects the hydraulic pump 71 and the swing motor 72, a control valve 73 (an example of a control valve) that is provided in the hydraulic circuit and controls the flow rate of hydraulic oil from the hydraulic pump 71 to the swing motor 72, and the engine 70 that drives the hydraulic pump 71. The swing control unit 803 is configured to control the drive of the swing motor 72 by controlling the aperture of the control valve 73 and the capacity of the hydraulic pump 71, but is not limited to this. That is, the swing control unit 803 may be configured to control the drive of the swing motor 72 by, for example, controlling at least one of the aperture of the control valve 73, the capacity of the hydraulic pump 71, and controlling the hydraulic pressure of the hydraulic circuit using a relief valve or the like.

[0165] (5) In each of the above embodiments, the storage unit 810 is configured to store the maximum allowable angular velocity map M1 and the convergence time map M2, but this is not limited thereto. For example, instead of the maximum allowable angular velocity map M1, a lateral acceleration map relating to the maximum allowable lateral acceleration acting on the attachment tip portion 10T may be stored as shown in Figures 6A and 10A, and the maximum allowable turning angular velocity may be calculated based on this lateral acceleration map. In other words, the drive control of the turning drive unit 7S may be realized in any manner as long as it drives and controls the turning drive unit 7S so as to satisfy the predetermined acceleration condition.

[0166] (6) In each of the above embodiments, the slewing drive unit 7S is composed of hydraulic equipment including a hydraulic pump 71, a slewing motor 72, and a control valve 73, but is not limited to this and may also be composed of electric equipment such as an electric motor.

[0167] (7) In each of the above embodiments, the attachment 10S is configured by the boom 16 and the jib 18, but this is not limited thereto and may be configured, for example, by only the boom 16. In other words, the attachment 10S may have any configuration as long as it has a load support part that supports the load 100 via a vertically hanging load rope.

[0168] (8) In each of the above embodiments, the crane 10 is configured as a mobile crane that can travel on the ground using a lower running body 14 (an example of a lower body), but this is not limited to this and may also be a fixed crane, such as a tower crane whose lower body is fixed to the ground.

[0169] (9) The present invention includes any combination of the above embodiments. [Explanation of symbols]

[0170] 7S: Swing drive unit 10: Crane 10S: Attachment 10T: Attachment tip (load support part) 12: Upper rotating body 14: Lower running body (lower body) 16: Boom (attachment) 18: Jib (attachment) 50: Main hoisting rope (hanging load rope) 70: Engine 71: Hydraulic pump 72: Swing motor 73: Control valve 74: Relief valve 77: First solenoid proportional valve 78: Second solenoid proportional valve 80: Crane control device 81:Operation section 83:Emergency stop operation section 100: Hanging load 800: Weight acquisition part 801: Working radius acquisition part 803: Turning control section 805: Moment of inertia acquisition unit A: Maximum allowable lateral acceleration CL: Rotation axis It: Threshold moment of inertia R: Working radius T0: Convergence time T1: Convergence time

Claims

1. A crane control device used for a crane including a lower body, an upper rotating body supported on the lower body so as to be rotatable about a rotation axis extending in a vertical direction relative to the lower body, an attachment connected to the upper rotating body and having a load support part that supports a load via a vertically hanging load rope, and a rotation drive part that can rotate the upper rotating body about the rotation axis relative to the lower body, a swing control unit that executes drive control of the swing drive unit; a working radius acquisition unit that acquires a working radius that is a horizontal distance between the rotation axis of the upper rotating body and the load support portion of the attachment, the rotation control unit is configured to execute drive control of the rotation drive unit so as to satisfy a predetermined acceleration condition that, when the rotation drive unit accelerates and decelerates the upper rotating body in the circumferential direction about the rotation axis, the lateral acceleration of the load support unit in the circumferential direction is equal to or less than a maximum allowable lateral acceleration that is a maximum allowable value determined according to the working radius, a crane control device in which the maximum allowable lateral acceleration is set based on the ratio of the maximum allowable lateral load in the circumferential direction of the load support part to the strength allowable weight in a first working radius range smaller than a predetermined working radius where a strength allowable weight, which is the maximum allowable weight of the load, set based on the strength limit of the attachment, is equal to a stable allowable weight, which is the maximum allowable weight of the load, set based on the posture stability limit of the attachment, and where the strength allowable weight is smaller than the stable allowable weight, while the maximum allowable lateral acceleration is set based on the ratio of the maximum allowable lateral load in the circumferential direction of the load support part to the stable allowable weight in a second working radius range larger than the predetermined working radius and where the stable allowable weight is smaller than the strength allowable weight.

2. The crane control device according to claim 1, A crane control device in which, when the working radius acquired by the working radius acquisition unit is within the second working radius range, the rotation control unit performs drive control of the rotation drive unit so as to reduce the convergence time, which is the time from the start of each operation to the end of each operation when the rotation drive unit accelerates and decelerates the upper rotating body in the circumferential direction, the larger the working radius.

3. The crane control device according to claim 1 or 2, the crane has an operation unit that receives an operation for rotating the upper rotating body and outputs an operation signal for the operation, The rotation control unit is configured to execute drive control of the rotation drive unit so that when it detects that the operating unit has been operated based on an operation signal from the operating unit, it accelerates the upper rotating body to a rotation angular velocity corresponding to the amount of operation, and when the operation is released, it decelerates the upper rotating body until it stops rotating, and when a non-full operation, which is an operation amount smaller than a full operation, is executed on the operating unit, the crane control device is configured to reduce the convergence time, which is the time from the start of the operation to the end of the operation, so that the rotation angular acceleration of the upper rotating body does not change when at least one of the acceleration operation and the deceleration operation is executed, compared to when the full operation is executed.

4. The crane control device according to claim 1 or 2, a weight acquisition unit that acquires the weight of the suspended load; Further comprising a memory unit that stores the rated load of the suspended load, The rated load of the lifted load is preset according to the working radius so as to match the strength allowable weight in the first working radius range and match the stability allowable weight in the second working radius range, the maximum allowable lateral acceleration specified in the predetermined acceleration condition is set so that when the weight of the suspended load is smaller than the rated load, it is higher by the ratio of the weight of the suspended load to the rated load compared to when the weight of the suspended load is equal to the rated load, A crane control device configured such that the slewing drive unit acquires the rated load of the load corresponding to the working radius based on the working radius acquired by the working radius acquisition unit, and performs drive control of the slewing drive unit so as to satisfy the specified acceleration condition based on the ratio between the acquired rated load and the weight of the load acquired by the weight acquisition unit.

5. The crane control device according to claim 1 or 2, The system further includes an inertia moment acquisition unit that acquires the inertia moment about the rotation axis of a group of rotating objects including the upper rotating body, the attachment, and the suspended load, The crane control device is configured to: when a limit angular acceleration, which is an upper limit value of the angular acceleration in the circumferential direction of the group of rotating objects and is determined based on the moment of inertia moment acquisition unit and the maximum output torque about the rotation axis that the rotation drive unit can output, is smaller than a maximum allowable angular acceleration determined based on the maximum allowable lateral acceleration and the working radius, execute drive control of the rotation drive unit so that the rotation angular acceleration of the upper rotating body is equal to or less than the limit angular acceleration; and when the limit angular acceleration is equal to or greater than the maximum allowable angular acceleration, execute drive control of the rotation drive unit so that the rotation angular acceleration of the upper rotating body is equal to or less than the maximum allowable angular acceleration.

6. The crane control device according to claim 1 or 2, When the upper rotating body is decelerated in the circumferential direction, the rotation control unit a first calculation process for calculating, as a target convergence time, a convergence time from the start of the deceleration operation to the end of the deceleration operation when the upper rotating body is decelerated at a maximum allowable angular acceleration that satisfies the predetermined acceleration condition; a second calculation process for calculating, using equation (1), a predicted convergence time Td for starting a deceleration operation from the current time point and stopping the upper rotating body at a predetermined target swing angle θt, where θs is the swing angle in the circumferential direction of the upper rotating body and ωs is the swing angular velocity of the upper rotating body at the current time point; A crane control device that executes drive control of the rotation drive unit so as to start a deceleration operation of the upper rotating body when the predicted convergence time Td matches the target convergence time. Td=2×(θt-θs) / ωs……Formula (1)

7. The crane control device according to claim 1 or 2, The turning drive unit is a variable displacement hydraulic motor; a hydraulic pump that discharges hydraulic oil to the hydraulic motor; a hydraulic circuit connecting the hydraulic pump and the hydraulic motor; a control valve provided in the hydraulic circuit for controlling an inflow flow rate of hydraulic oil from the hydraulic pump to the hydraulic motor, A crane control device, wherein the swing control unit performs drive control of the hydraulic motor by performing at least one of control of the opening of the control valve, control of the capacity of the hydraulic pump, and control of the hydraulic pressure of the hydraulic circuit.

8. The crane control device according to claim 1 or 2, an emergency stop operation unit that outputs an emergency stop signal for bringing the upper rotating body to an emergency stop when a predetermined operation is received from an operator during rotation of the upper rotating body, The turning drive unit is a variable displacement hydraulic motor; a hydraulic pump that discharges hydraulic oil to the hydraulic motor; a hydraulic circuit connecting the hydraulic pump and the hydraulic motor; a control valve provided in the hydraulic circuit for controlling an inflow flow rate of hydraulic oil from the hydraulic pump to the hydraulic motor; an engine that drives the hydraulic pump, When the rotation control unit receives the emergency stop signal from the emergency stop operation unit while the upper rotating body is rotating, it stops the engine to stop the rotation drive unit, and sets a convergence time from the start to the end of the deceleration operation when the upper rotating body is decelerated at the maximum allowable angular acceleration that satisfies the specified acceleration condition, and performs drive control of the rotation drive unit so as to transition the control valve from an open state to a closed state within the set convergence time.

9. A lower body and an upper rotating body supported by the lower body so as to be rotatable about a rotation axis extending in the vertical direction relative to the lower body; an attachment connected to the upper rotating body, the attachment having a load support portion that supports a load via a vertically suspended load rope; a rotation drive unit capable of rotating the upper rotating body relative to the lower main body about the rotation axis; A crane equipped with the control device according to claim 1 or 2.

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