Crane and crane control method

Abstract

To provide a crane and a crane control method capable of avoiding an occurrence of irregular winding in a winch device due to sudden deceleration of the winding of a hanging rope without deteriorating work efficiency as much as possible.SOLUTION: A load measurement device 451 measures a load of a suspended load hung on a hanging rope 32. An allowable attenuation rate deriving part 66 derives an allowable attenuation rate dVL1 representing an allowable value of the attenuation rate for winding of the hanging rope 32 according to the measured load by the load measurement device 451. The allowable attenuation rate deriving part 66 derives a smaller allowable attenuation rate dVL1 when the measured load by the load measuring device 451 is small than when it is large. A winch control part 64 decelerates its winding while restricting the winding of the hanging rope 32 within the range of the allowable attenuation rate dVL1 by the winch device 162.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a crane that controls the winding of a hoisting rope and a method for controlling the crane. [Background technology]

[0002] The crane includes a boom that supports a hoisting rope and a winch device that winds up or unwinds the hoisting rope. A load is suspended from the hoisting rope. The winch device includes a winch drum that winds up the hoisting rope and a motor that rotates the winch drum.

[0003] The winding state of the hoisting rope on the winch drum may become disordered. The state in which the rope is wound disorderly is called a disorderly winding state. If the disorderly winding state occurs, it may lead to a dangerous situation, such as a temporary sudden drop of the load.

[0004] It is known that in the crane, a hydraulic cylinder applies a constant load to the hoisting rope via a link, and a control device stops the winch when the angle of the link exceeds a predetermined angle during the payout of the hoisting rope (see, for example, Patent Document 1). This prevents the hoisting rope from being paid out excessively when the load lands on the floor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2000-313592 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, when the suspended load is light, if the winch device suddenly decelerates the winding of the suspension rope, the suspension rope may temporarily slacken, which may cause the above-mentioned disorderly winding state to occur in the winch device.

[0007] On the other hand, gradually slowing down the winding of the hoisting rope leads to a decrease in the work efficiency of the crane transporting the suspended load.

[0008] An object of the present invention is to provide a crane and a crane control method that can avoid the occurrence of a disorderly winding state in a winch device caused by a sudden deceleration in the winding of a hoisting rope, without deteriorating work efficiency as much as possible. [Means for solving the problem]

[0009] A crane according to one aspect of the present invention includes a boom, a winch device, a winch control unit, a load measuring device, and an allowable deceleration rate deriving unit. The boom supports a suspension rope. The winch device winds or pays out the suspension rope. The winch control unit controls the winch device. The load measuring device measures the load of a load suspended from the suspension rope. The allowable deceleration rate deriving unit derives an allowable deceleration rate that represents an allowable value of a deceleration rate for winding the suspension rope in accordance with the measured load of the load measuring device. The allowable deceleration rate deriving unit derives the allowable deceleration rate that is smaller when the measured load of the load measuring device is smaller than when the measured load is large. When the winch control unit decelerates the winding of the suspension rope by the winch device while the winch device is winding the suspension rope, the winch control unit decelerates while limiting the speed within the range of the allowable deceleration rate.

[0010] A crane control method according to another aspect of the present invention is a method for controlling a crane including the boom, the winch device, and the load measuring device. The crane control method includes a step of deriving an allowable deceleration rate that represents an allowable value of a deceleration rate of winding of the suspension rope in accordance with the load measured by the load measuring device, and deriving the allowable deceleration rate that is smaller when the measured load of the load measuring device is small than when it is large. Furthermore, the crane control method includes a step of controlling the winch device to decelerate the winding of the suspension rope by the winch device while the winch device is winding the suspension rope, while limiting the deceleration rate within a range of the allowable deceleration rate. Effect of the Invention

[0011] According to the present invention, it is possible to provide a crane and a crane control method that can avoid the occurrence of a disorderly winding state on the winch drum caused by a sudden deceleration in the winding of the suspension rope, without causing a decrease in work efficiency as much as possible. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a configuration diagram of a crane according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing a configuration of control-related devices in the crane according to the embodiment. [Diagram 3] FIG. 3 is a block diagram showing the configuration of a control device in a crane according to the embodiment. [Figure 4] FIG. 4 is a flowchart showing an example of a procedure for limiting control of winding of a hoisting rope in a crane according to the embodiment. [Diagram 5] Figure 5 is a graph showing an example of the correspondence between the hanging load and the allowable deceleration rate for winding the hanging rope in a crane according to an embodiment, where Figure 5(A) is a graph showing an example in which an allowable deceleration rate that changes continuously depending on the hanging load is derived, Figure 5(B) is a graph showing an example in which an allowable deceleration rate that changes in multiple stages depending on the hanging load is derived, and Figure 5(C) is a graph showing an example in which an allowable deceleration rate that changes in two stages depending on the hanging load is derived. [Figure 6] FIG. 6 is a graph showing the relationship between the allowable time for stopping winding of the hoisting rope and the first upper limit winding speed in the crane according to the embodiment. [Figure 7] FIG. 7 is a graph showing the relationship between the time required for stopping winding of the hoisting rope and the second upper limit winding speed in the crane according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is an example of the present invention, and is not intended to limit the technical scope of the present invention.

[0014] [Outline of crane 10] A crane 10 according to an embodiment of the present invention is a work machine that hoists and moves a load 9. Below, an example in which the crane 10 is a jib crane will be described.

[0015] 1, the crane 10 includes a lower traveling body 11, an upper rotating body 12, a cab 13, a gantry 15, a winch device 16, a counterweight 17, a boom 21, a hoisting rope 31, a hoisting rope 32, and a hook 30. The winch device 16 includes a first winch device 161 and a second winch device 162.

[0016] The lower traveling body 11 is a base portion that supports the upper rotating body 12 so that it can rotate. The crane 10 shown in Fig. 1 is a mobile crane. Therefore, the lower traveling body 11 of the crane 10 is equipped with a traveling device 14 that allows the entire crane 10 to travel. Fig. 1 shows an example in which the traveling device 14 is a crawler-type device. The lower traveling body 11 is an example of a lower base.

[0017] The upper rotating body 12 is rotatably connected to the upper part of the lower traveling body 11. The upper rotating body 12 is integrally configured with a cab 13, a gantry 15, and a winch device 16. The gantry 15 is fixed to the upper rotating body 12 in a state in which it stands up from the upper rotating body 12. Furthermore, the upper rotating body 12 supports the winch device 16, a counterweight 17, and a boom 21.

[0018] The upper rotating body 12 is rotated by a rotation motor 441 provided on the lower traveling body 11 (see FIG. 2). The cab 13 is a driver's room. The boom 21 is connected to the upper rotating body 12 so as to be able to rise and fall.

[0019] The hoisting rope 31 is hung on a gantry sheave 23 provided at the tip of the gantry 15, and both ends of the hoisting rope 31 are connected to the boom 21 and the first winch device 161, respectively. The first winch device 161 supports the boom 21 via the hoisting rope 31.

[0020] The first winch device 161 changes the hoisting angle of the boom 21 by winding or unwinding the hoisting rope 31. The first winch device 161 is equipped with a first winch motor 442 that rotates and drives a drum that winds up the hoisting rope 31 (see FIG. 2).

[0021] The hoisting rope 32 is hung on a point sheave 25 provided at the tip of the boom 21, and the hook 30 is connected to the tip of the hoisting rope 32.

[0022] The load 9 is suspended from the hook 30. As a result, the load 9 is suspended from the boom 21 by the suspending rope 32. A suspending load LD1 is applied to the suspending rope 32. The boom 21 supports the suspending rope 32.

[0023] The second winch device 162 raises and lowers the hook 30 and the suspended load 9 by winding or unwinding the suspending rope 32. The second winch device 162 includes a second winch motor 443 that rotates and drives a drum that winds up the suspending rope 32 (see FIG. 2).

[0024] The counterweight 17 balances the load of the load 9 suspended from the boom 21 and the hook 30 .

[0025] As shown in FIG. 2, the crane 10 includes drive system devices such as an engine 41, a hydraulic pump 42, a control valve 43, and a hydraulic actuator 44, an operation device 5, a control device 6, and a display device 7.

[0026] The engine 41 is a diesel engine that drives a hydraulic pump 42. The control valve 43 controls the flow of hydraulic oil between a hydraulic actuator 44 and the hydraulic pump 42, etc., in accordance with a control signal output from the control device 6.

[0027] The hydraulic actuator 44 includes hydraulic motors such as a swing motor 441, a first winch motor 442, and a second winch motor 443. The swing motor 441 drives the upper swing body 12 to swing.

[0028] The first winch device 161 includes a drum for winding up the hoisting rope 31 and a first winch motor 442 for driving and rotating the drum. The second winch device 162 includes a drum for winding up the hoisting rope 32 and a second winch motor 443 for driving and rotating the drum.

[0029] Devices for human interface such as the operation device 5 and the display device 7 are provided in the cab 13. Furthermore, the crane 10 also includes a status measuring device 45 that measures the status of various devices included in the crane 10.

[0030] The control device 6 is capable of communicating with other devices such as the state measuring device 45 and the operation device 5 through an in-vehicle network 100 such as a CAN (Controller Area Network).

[0031] The operation device 5 is a device that accepts operations by the operator. The display device 7 is a device that displays information, and is, for example, a panel display device such as a liquid crystal display unit.

[0032] The operation device 5 includes a rotation operation device 51, a raising and lowering operation device 52, a lifting operation device 53, and an operation input device 54, etc.

[0033] The turning operation device 51 includes a turning lever 511 that can be displaced in two directions from a neutral position. The turning operation device 51 outputs a signal instructing the rotation direction and rotation speed of the turning motor 441 to the control device 6 according to the operation direction and operation amount of the turning lever 511.

[0034] The hoisting operation device 52 is equipped with a hoisting lever 521 that can be displaced in two directions from a neutral position. The hoisting operation device 52 outputs a signal to the control device 6 instructing the rotation direction and rotation speed of the first winch motor 442 according to the operation direction and amount of the hoisting lever 521.

[0035] The lifting operation device 53 includes a lifting lever 531 that can be displaced in two directions from a neutral position. The lifting operation device 53 outputs control signals for the rotation direction and rotation speed of the second winch motor 443 to the control device 6 according to the operation direction and operation amount of the lifting lever 531.

[0036] The control device 6 controls the control valves 43 corresponding to the swing motor 441, the first winch motor 442 and the second winch motor 443, respectively, in response to control signals obtained from the swing operation device 51, the hoisting operation device 52 and the lifting operation device 53, respectively.

[0037] The operation input device 54 accepts information input by the operator. For example, the operation input device 54 is a touch panel that is integrated with the display device 7. The operation input device 54 may also be a device that accepts information input by voice operation of the operator.

[0038] The state measuring device 45 includes a load meter 451, a hoisting angle measuring device 452, and a payout length measuring device 453. The measurement results of the various state measuring devices 45 are transmitted to the control device 6 through the in-vehicle network 100.

[0039] The load meter 451 measures the load of the suspended load 9 applied to the boom 21. For example, the load meter 451 may be a load sensor such as a load cell attached to the hoisting rope 31. The load meter 451 is an example of a load measuring device.

[0040] The hoisting angle measuring device 452 measures the hoisting angle of the boom 21. The hoisting angle measuring device 452 may be an angle meter attached to the boom 21.

[0041] The payout length measuring device 453 is a device that measures the payout length of the suspension rope 32. For example, the payout length measuring device 453 measures the payout length of the suspension rope 32 by counting the number of rotations of a rotating body that contacts the suspension rope 32 and rotates in response.

[0042] 3, the control device 6 includes a Micro Processing Unit (MPU) 601, a Random Access Memory (RAM) 602, a non-volatile memory 603, and a signal interface 604. The RAM 602 and the non-volatile memory 603 are computer-readable storage devices.

[0043] The MPU 601 is an example of a processor that executes various types of data processing and control by executing programs stored in advance in the non-volatile memory 603 .

[0044] The RAM 602 is a volatile memory that temporarily stores the programs executed by the MPU 601 and data derived or referenced by the MPU 601 .

[0045] The non-volatile memory 603 pre-stores the programs executed by the MPU 601 and data referenced by the MPU 601. For example, the non-volatile memory 603 may be an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory.

[0046] The signal interface 604 converts the measurement signal of the state measurement device 45 into digital data and transmits it to the MPU 601. Furthermore, the signal interface 604 converts the control command output by the MPU 601 into a control signal such as a current signal or a voltage signal, and outputs it to the device to be controlled.

[0047] The MPU 601 of the control device 6 includes a number of processing modules that are realized by executing a predetermined computer program. The processing modules include a main processing unit 61, a turning control unit 62, a hoisting control unit 63, a lifting control unit 64, and a drooping length calculation unit 65 (see FIG. 2).

[0048] The main processing unit 61 executes control of the start of various processes when the control device 6 is started, control of the display device 7, information input processing in accordance with input operations on the operation input device 54, and the like.

[0049] The swing control unit 62 controls the control valve 43 corresponding to the swing motor 441 to control the swing direction and swing speed of the upper swing body 12 .

[0050] The hoisting control unit 63 controls the control valve 43 corresponding to the first winch motor 442, thereby controlling the reeling out or reeling in of the hoisting rope 31 by the first winch device 161. In other words, the hoisting control unit 63 controls the hoisting angle of the boom 21.

[0051] The lifting / lowering control section 64 controls the control valve 43 corresponding to the second winch motor 443, thereby controlling the reeling out or reeling in of the suspending rope 32 by the second winch device 162. In other words, the lifting / lowering control section 64 controls the height of the suspended load 9.

[0052] The lifting / lowering operation device 53 is an example of a winch operation device that accepts an operation to instruct the operation of the second winch device 162. The lifting / lowering control unit 64 is an example of a winch control unit that controls the second winch device 162 in response to an operation on the lifting / lowering operation device 53.

[0053] The hanging length derivation unit 65 derives the hanging length L1 of the suspension rope 32 by correcting the detection result of the payout length measuring device 453 based on the preset length of the boom 21 and the measured angle of the hoisting angle measuring device 452 (see Figure 1).

[0054] The payout length measuring device 453 and the hanging length lead-out unit 65 are an example of a hanging length measuring device that measures the hanging length L1 of the suspension rope 32. The lifting control unit 64 controls the control valve 43 corresponding to the first winch motor 442, thereby controlling the hanging length L1.

[0055] Incidentally, when the suspended load 9 is light, if the second winch device 162 suddenly decelerates the winding of the suspending rope 32, the suspending rope 32 may temporarily slacken, which may cause the second winch device 162 to become irregularly wound as described above.

[0056] On the other hand, gradually slowing down the winding speed of the hoisting rope 32 leads to a decrease in the work efficiency of the crane 10 in transporting the load 9.

[0057] In the crane 10, the control device 6 executes a hoisting rope winding limit control, which will be described later. This allows the crane 10 to avoid the occurrence of the disorderly winding state in the second winch device 162, which would be caused by a sudden deceleration in the winding of the hoisting rope 32, without deteriorating the work efficiency as much as possible.

[0058] In this embodiment, the MPU 601 of the control device 6 further includes an allowable deceleration rate derivation unit 66, a first upper limit speed derivation unit 67, and a second upper limit speed derivation unit 68 as processing modules realized by executing the computer program (see FIG. 2).

[0059] The lift control unit 64, the allowable deceleration rate derivation unit 66, the first upper limit speed derivation unit 67, and the second upper limit speed derivation unit 68 execute the suspension rope winding limit control.

[0060] [Limit control of lifting rope winding] Hereinafter, an example of a procedure for the hoisting rope winding limit control in the crane 10 will be described with reference to the flowchart shown in FIG.

[0061] For example, the allowable deceleration rate deriving unit 66 starts the suspension rope winding limiting control when the suspension load LD1, which is the load measured by the load meter 451, changes beyond a predetermined change width.

[0062] In the following description, S1, S2, . . . represent identification symbols of multiple steps in the suspension rope winding limit control.

[0063] <Process S1> In the suspending rope winding limit control, the allowable deceleration rate deriving unit 66 acquires data of the suspending load LD1 from the load meter 451, and derives an allowable deceleration rate dVL1 that indicates an allowable value of the deceleration rate of the winding of the suspending rope 32 in accordance with the suspending load LD1 (see FIG. 5). Furthermore, the process of step S2 described later is executed.

[0064] For example, the permissible deceleration rate dVL1 is a positive value. In this case, the larger the value of the permissible deceleration rate dVL1, the more rapid the deceleration permitted for the winding of the suspension rope 32. In other words, the smaller the value of the permissible deceleration rate dVL1, the more gradually the deceleration of the winding of the suspension rope 32 is restricted.

[0065] As shown in Fig. 5, the allowable deceleration rate deriving unit 66 derives a smaller allowable deceleration rate dVL1 when the hanging load LD1 is small than when it is large. Figs. 5(A) to (C) show three examples of a method for deriving the allowable deceleration rate dVL1 from the hanging load LD1.

[0066] Fig. 5(A) shows an example in which an allowable deceleration rate dVL1 that changes continuously in response to the hanging load LD1 is derived. Fig. 5(B) shows an example in which an allowable deceleration rate dVL1 that changes in multiple stages in response to the hanging load LD1 is derived. Fig. 5(C) shows an example in which an allowable deceleration rate dVL1 that changes in two stages in response to the hanging load LD1 is derived.

[0067] For example, the permissible deceleration ratio deriving unit 66 derives the permissible deceleration ratio dVL1 by applying the hanging load LD1 to a predetermined calculation formula or lookup table that represents the relationship between the hanging load LD1 and the permissible deceleration ratio dVL1.

[0068] <Process S2> In step S2, the first upper limit speed derivation unit 67 derives a first upper limit winding speed Vmx1 based on the permissible deceleration rate dVL1 derived in step S1 and a predetermined permissible time t1. Furthermore, the process of step S3, which will be described later, is executed.

[0069] As shown in FIG. 6, the first upper limit speed derivation unit 67 derives as the first upper limit winding speed Vmx1 the first start speed Vs1 in the case where the second winch device 162 decelerates the winding of the suspension rope 32 from the first start speed Vs1 at the allowable deceleration rate dVL1 and it takes a preset allowable time t1 for the second winch device 162 to stop.

[0070] For example, the first upper limit speed derivation unit 67 derives the first upper limit winding speed Vmx1 based on the following formula (1).

number

[0071] <Process S3> In step S3, the lifting control unit 64 determines whether the second winch device 162 is winding the suspension rope 32, and if it determines that the second winch device 162 is winding the suspension rope 32, it transitions to the next step S4.

[0072] The lift control unit 64 controls the second winch device 162 in accordance with the operation on the lift operation device 53 in parallel with the processes from step S3 onwards.

[0073] From step S4 onwards, the lifting / lowering control unit 64 controls the second winch device 162 in accordance with the operation of the lifting / lowering operation device 53, within the range in which the winding speed of the suspension rope 32 does not exceed the first upper limit winding speed Vmx1 or the second upper limit winding speed Vmx2 described later.

[0074] The lift control unit 64 derives the rate of change of the length measured by the payout length measuring device 453 and the rate of change of the rate of change of the measured length, thereby deriving the winding speed and acceleration of the suspension rope 32.

[0075] <Process S4> In step S4, second upper limit speed derivation unit 68 derives a second upper limit winding speed Vmx2 based on the permissible deceleration rate dVL1 derived in step S1 and the drooping length L1 and minimum drooping length L0 derived by drooping length derivation unit 65 (see FIG. 7). Furthermore, the process of step S5, which will be described later, is executed.

[0076] The minimum drooping length L0 is set in advance by, for example, the main processing unit 61 in accordance with an input operation to the operation input device 54.

[0077] The hanging length L1 is a length measured by the hanging length measuring device consisting of the payout length measuring device 453 and the hanging length lead-out unit 65.

[0078] As shown in FIG. 7, the second upper limit speed derivation unit 68 derives as the second upper limit winding speed Vmx2 the second start speed Vs2 at which the drooping length L1 changes from the current measured length to the minimum drooping length L0 before the second winch device 162 stops if the second winch device 162 decelerates the winding of the suspension rope 32 from the second start speed Vs2 at the allowable deceleration rate dVL1.

[0079] The time required for stopping t2 in FIG. 7 is the time required for the second winch device 162 to stop by decelerating at the permissible deceleration rate dVL1 from a state in which the second winch device 162 is winding the suspending rope 32 at the second start speed Vs2.

[0080] Moreover, the wound length LUP1 in FIG. 7 is the wound length of the suspension rope 32 when the drooping length L1 changes from the currently measured length to the minimum drooping length L0.

[0081] For example, the second upper limit speed derivation unit 68 derives the second upper limit winding speed Vmx2 based on the following formula (2).

number

[0082] <Process S5> In step S5, the lift control unit 64 executes control to limit the winding speed of the suspension rope 32 by the second winch device 162 to within the range of the first upper limit winding speed Vmx1 and within the range of the first upper limit winding speed Vmx1. Furthermore, the processing of step S6 described later is executed.

[0083] That is, when the lifting / lowering control unit 64 controls the second winch device 162 in accordance with an operation on the lifting / lowering operation device 53, if the winding speed of the suspension rope 32 is equal to or lower than the first upper limit winding speed Vmx1 and the second upper limit winding speed Vmx2, the lifting / lowering control unit 64 controls the second winch device 162 in accordance with an operation on the lifting / lowering operation device 53.

[0084] On the other hand, when the lifting control unit 64 controls the second winch device 162 in accordance with the operation of the lifting operation device 53, if the winding speed of the hanging rope 32 exceeds the first upper limit winding speed Vmx1 or the second upper limit winding speed Vmx2, the lifting control unit 64 controls the second winch device 162 so that the winding speed of the hanging rope 32 becomes the lower of the first upper limit winding speed Vmx1 and the second upper limit winding speed Vmx2.

[0085] <Process S6> In step S6, the lift control unit 64 determines whether or not a deceleration operation for decelerating the winding speed of the suspension rope 32 has been performed on the lift operation device 53.

[0086] Then, if it is determined that the deceleration operation has been performed, the lift control section 64 shifts the process to steps S7 and S8, and if not, shifts the process to step S8.

[0087] <Process S7, S8> The lift control section 64 executes deceleration rate limiting control in step S7, and determines whether the second winch device 162 has stopped in step S8.

[0088] The deceleration rate limiting control is a control for decelerating the second winch device 162 while the second winch device 162 is winding the suspension rope 32, while limiting the deceleration rate to within the range of the allowable deceleration rate dVL1.

[0089] For example, the lifting control unit 64 limits the deceleration rate of the winding of the hoisting rope 32 to within the range of the allowable deceleration rate dVL1 by feedback controlling the control valve 43 corresponding to the second winch motor 443 based on the acceleration of the winding of the hoisting rope 32.

[0090] The lifting / lowering control section 64 continues the deceleration rate limiting control of step S7 until it determines that the second winch device 162 has stopped. Then, when it determines that the second winch device 162 has stopped, the lifting / lowering control section 64 ends the suspension rope winding limiting control.

[0091] When the deceleration operation on the lift operation device 53 is released, the lift control unit 64 skips the deceleration rate limiting control.

[0092] As described above, when the lifting / lowering control unit 64 and the allowable deceleration rate derivation unit 66 control the stopping of the winding of the hanging rope 32 when the hanging load LD1 is small, they gently decelerate and stop the winding of the hanging rope 32 (see steps S1 and S6 in Figure 4 and Figure 5).

[0093] Therefore, it is possible to prevent the occurrence of the disorderly winding state in the second winch device 162 caused by a sudden deceleration in the winding of the suspension rope 32.

[0094] On the other hand, when controlling the stop of winding up of the hanging rope 32 when the hanging load LD1 is large, the lifting control unit 64 and the allowable deceleration rate derivation unit 66 relax the restriction on the deceleration of the winding up of the hanging rope 32, or do not actually impose any restriction (see steps S1 and S6 in Figure 4 and Figure 5).

[0095] Therefore, when the hoisting load LD1 is relatively large, that is, when the above-mentioned disorderly winding state is unlikely to occur when the winding of the hoisting rope 32 is stopped, deterioration of the work efficiency of the transport of the load 9 by the crane 10 is avoided.

[0096] Furthermore, the winding speed of the suspending rope 32 is limited within the range of the first upper limit winding speed Vmx1 (see steps S2 and S5 in FIG. 4 and FIG. 6). As a result, even if the deceleration rate at the time of stopping winding of the suspending rope 32 is limited within the range of the allowable deceleration rate dVL1, the time required to stop winding of the suspending rope 32 falls within the predetermined allowable time t1.

[0097] Therefore, the time required to stop winding of the suspending rope 32 is prevented from becoming too long due to the deceleration rate limiting control (step S6).

[0098] Furthermore, the winding speed of the suspending rope 32 is limited to within the range of the second upper limit winding speed Vmx2 (see steps S4 and S5 in FIG. 4 and FIG. 7). This prevents the load 9 from being lifted above the height corresponding to the minimum drooping length L0, even if the deceleration rate at the time of stopping winding of the suspending rope 32 is limited to the range of the allowable deceleration rate dVL1.

[0099] Control based on the second upper limit winding speed Vmx2 is effective when it is desired to limit the lifting height of the load 9 to a predetermined height or below, and when it is desired to prevent the load 9 from rising to near the tip of the boom 21.

[0100] [Application example] Application examples of the crane 10 will now be described.

[0101] In the crane 10, the main processing unit 61 selects an operating mode for the speed limit control from a plurality of candidates in accordance with a mode selection operation on the operation input device 54, and the lifting control unit 64 executes or does not execute the speed limit control in accordance with the selected operating mode.

[0102] The operation mode is a mode in which one or both of the speed limit control based on a first upper limit winding speed Vmx1 and the speed limit control based on a second upper limit winding speed Vmx2 are omitted, or a mode in which both are performed.

[0103] It is also conceivable that in the crane 10, the processing modules and controls relating to one or both of the first upper limit winding speed Vmx1 and the second upper limit winding speed Vmx2 may be omitted.

[0104] Also, in the crane 10, the allowable deceleration rate deriving unit 66 may derive a target winding speed at which the winding of the hoisting rope 32 gradually changes from the current speed until it stops, instead of deriving the allowable deceleration rate dVL1. The target winding speed is a target speed that reflects the allowable deceleration rate dVL1. [Explanation of symbols]

[0105] 5: Operating device 6: Control device 7:Display device 9: Suspended load 10: Crane 11: Lower running body 12: Upper rotating body 13: Cab 14: Running gear 15: Gantry 16: Winch device 17: Counterweight 21: Boom 23: Gantry 25: Point Sieve 30: Hook 31: Descending rope 32: Suspension rope 41: Engine 42: Hydraulic pump 43: Control valve 44: Hydraulic actuator 45: State measurement device 51: Swing operation device 52:Luffing operation device 53: Lifting device 54: Operation input device 61: Main processing section 62: Rotation control section 63: Elevation control section 64: Lift control section 65: Droop length derivation part 66: Allowable deceleration rate derivation part 67: 1st upper limit speed derivation section 68: 2nd upper limit speed derivation section 100: In-vehicle network 161: First winch device 162: Second winch device 441: Swing motor 442: 1st winch motor 443: 2nd winch motor 451:Load cell 452:Elevation angle measuring device 453: Measuring equipment 511: Swivel lever 521: Lift lever 531: Lift lever 601: MPU 602: RAM 603: Non-volatile memory 604: Signal interface LD1: Hanging load Vmx1: First upper limit winding speed Vmx2: Second upper limit winding speed Vs1: 1st starting speed Vs2: 2nd starting speed dVL1: Allowable deceleration rate t1: Allowable time t2: Required stop time

Claims

1. A boom that supports the hoisting rope, A winch device that winds up or unwinds the suspension rope; A winch control unit that controls the winch device; A load measuring device that measures the load of a load suspended by the suspension rope; an allowable deceleration rate deriving unit that derives an allowable deceleration rate that represents an allowable value of a deceleration rate of winding of the suspension rope in accordance with the measured load of the load measuring device, the allowable deceleration rate deriving unit derives the allowable deceleration rate which is smaller when the measured load of the load measuring device is small than when the measured load is large, The winch control unit, when slowing down the winding of the suspension rope by the winch device while the winch device is winding the suspension rope, decelerates while limiting the deceleration rate within the range of the allowable deceleration rate.

2. A boom supporting a hoisting rope; A winch device that winds up or unwinds the suspension rope; A winch control unit that controls the winch device; A load measuring device that measures the load of a load suspended by the suspension rope; an allowable deceleration rate deriving unit that derives an allowable deceleration rate that represents an allowable value of a deceleration rate for winding the suspension rope in accordance with the measured load of the load measuring device; an upper limit speed derivation unit that derives an upper limit winding speed, which is the start speed when a preset allowable time is required for the winch device to stop if the winch device decelerates the winding of the suspension rope from a start speed at the allowable deceleration rate, the allowable deceleration rate deriving unit derives the allowable deceleration rate which is smaller when the measured load of the load measuring device is small than when the measured load is large, the winch control unit, when decelerating the winding of the suspension rope by the winch device while the winch device is winding the suspension rope, decelerates while limiting the deceleration rate within a range of the allowable deceleration rate, The winch control unit limits the winding speed of the suspension rope by the winch device to within the range of the upper limit winding speed.

3. A boom supporting a hoisting rope; A winch device that winds up or unwinds the suspension rope; A winch control unit that controls the winch device; A load measuring device that measures the load of a load suspended by the suspension rope; A hanging length measuring device that measures the hanging length of the suspension rope; an allowable deceleration rate deriving unit that derives an allowable deceleration rate that represents an allowable value of a deceleration rate for winding the suspension rope in accordance with the measured load of the load measuring device; an upper limit speed derivation unit that derives an upper limit winding speed, which is the start speed when the drooping length changes from the measured length to a preset minimum drooping length before the winch device stops if the winch device decelerates the winding of the suspension rope from a start speed at the allowable deceleration rate, according to the length measured by the drooping length measuring device, A crane, wherein the winch control unit limits the winding speed of the suspension rope by the winch device to within the range of the upper limit winding speed derived based on the measured length of the hanging length.

4. A crane control method for controlling a crane including a boom supporting a hoisting rope, a winch device for winding or unwinding the hoisting rope, and a load measuring device for measuring a load of a load suspended by the hoisting rope, comprising: deriving an allowable deceleration rate that represents an allowable value of a deceleration rate of winding of the suspension rope in accordance with the load measured by the load measuring device, and deriving the allowable deceleration rate that is smaller when the load measured by the load measuring device is smaller than when the load is large; and when the winch device is controlling the winch device to decelerate the winding of the suspension rope while the winch device is winding the suspension rope, the deceleration is limited within the range of the allowable deceleration rate.

5. A crane control method for controlling a crane equipped with a boom supporting a hoisting rope, a winch device for winding or unwinding the hoisting rope, and a load measuring device for measuring the load of a load suspended by the hoisting rope, comprising: deriving an allowable deceleration rate that represents an allowable value of a deceleration rate of winding of the suspension rope in accordance with the load measured by the load measuring device, and deriving the allowable deceleration rate that is smaller when the load measured by the load measuring device is smaller than when the load is large; A step of deriving an upper limit winding speed, which is the start speed when a preset allowable time is required for the winch device to stop if the winch device decelerates the winding of the suspension rope from the start speed at the allowable deceleration rate; a step of controlling the winch device to decelerate the winding of the suspension rope by the winch device while the winch device is winding the suspension rope, while limiting the deceleration rate within a range of the allowable deceleration rate; and limiting the winding speed of the hoisting rope by the winch device to within the range of the upper limit winding speed.

6. A crane control method for controlling a crane equipped with a boom supporting a suspension rope, a winch device for winding or unwinding the suspension rope, a load measuring device for measuring the load of a load suspended by the suspension rope, and a sagging length measuring device for measuring the sagging length of the suspension rope, comprising: deriving an allowable deceleration rate that represents an allowable value of a deceleration rate of winding of the suspension rope in accordance with the load measured by the load measuring device, and deriving the allowable deceleration rate that is smaller when the load measured by the load measuring device is smaller than when the load is large; a step of deriving an upper limit winding speed, which is the start speed when the winch device decelerates the winding of the suspension rope from a start speed at the allowable deceleration rate, according to the length measured by the drooping length measuring device, in the case where the drooping length changes from the measured length to a preset minimum drooping length before the winch device stops; and limiting the winding speed of the hoisting rope by the winch device to within the range of the upper limit winding speed derived based on the measured length of the sagging length.

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