JPH10120367A - Sway control device for construction machinery - Google Patents

Abstract

(57) [Summary] [PROBLEMS] In a steady rest control device for a construction machine taking into account the natural frequency of a rope suspension system, an operator determines that the length of the rope has become short and the steady rest control has stopped functioning. To be recognized. SOLUTION: When a controller 6 detects that a rope length L has reached a predetermined value L0 at which the anti-sway control does not function, an alarm is issued from an alarm device 30 and an alarm lamp 31, and the anti-sway control is provided to an operator. Recognize that it no longer works. The steady rest control may be stopped before the rope length L reaches the predetermined value L0, or the winding of the hoisting rope may be stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steady rest control device for a construction machine which suppresses vibration of a suspended load suspended from a boom or the like by a rope.

[0002]

2. Description of the Related Art Conventionally, various methods have been proposed for turning or moving a crane so that a suspended load hung on the crane does not swing. For example,
“Transactions of the Japan Society of Mechanical Engineers No.948-3 (199
4.11.5, pp. 298 to 300) ”, a ceiling crane that moves the ceiling in a factory or the like, detects a swing angle θ of a hoisting rope for suspending a suspended load, and detects a predetermined acceleration. A steady rest control system for a crane in which a suspended load is moved according to a pattern is described. In this method, control is performed as follows.

In an ideal acceleration pattern, the initial shake angle θ (0) = 0, the initial angular velocity θ (0) / dt = 0, and the residual shake angle θ (R) = 0 and the residual shake velocity θ at the destination (R) / dt = 0. The ideal deflection angle and angular velocity obtained when the suspended load travels in such an ideal acceleration pattern are calculated based on the actual deflection angle actually detected by the deflection angle sensor and the actual deflection angle calculated from the detected value. The anti-vibration feedback control is performed by changing the traveling acceleration at an effective timing so that the ideal deflection angle and the angular velocity are obtained as compared with the angular velocity.

[0004] The natural frequency (swing cycle) of the suspended load suspended by the hoisting rope when it swings is determined when the weight of the suspended rope is large and the mass of the suspended rope is negligible. In each case where the mass of the hoisting rope is small and cannot be ignored, it is expressed by the following equations (1) and (2).

[0005]

(Equation 1)

As described above, the period of the swing of the suspended load fluctuates depending on the natural frequency determined by the length of the rope.
It is necessary to perform steadying control in consideration of the natural frequency. In the steady rest control method of the overhead crane, the length of the hoisting rope of the overhead crane is substantially constant, so that control without taking the natural frequency into account is not performed. There is no problem because no fluctuation occurs. However, in mobile cranes that work outdoors, the length of the hoisting rope fluctuates. Unless steady rest control that takes into account the natural frequency based on the rope length is performed, the swing of the suspended load can be reduced. Cannot be suppressed. For this reason, there has been proposed a steady rest control device including a vibration suppressing device that performs steady rest control of the suspended load in consideration of the natural frequency based on the weight of the suspended load and the rope length (for example, Japanese Unexamined Patent Application Publication No. Hei. 18596).

[0007] In such a swing load swing control device, the vibration suppressing device changes the swing angular velocity of the upper swing body of the crane based on the natural frequency of the swing of the swing load, thereby changing the swing of the swing load. It is trying to suppress. For example, when the suspended load is swinging, the swing is reduced by rotating the upper revolving unit at an angular velocity that reduces the swing.

[0008]

However, in the steady rest control device for a suspended load in consideration of the above natural frequency, when the rope length becomes short and the natural frequency becomes large, the rotation of the upper swing body becomes its natural frequency. Since it is impossible to follow the vibration frequency, if the rope length becomes less than a certain value, the vibration of the suspended load cannot be reduced by the vibration suppressing device. Therefore, if the rope length falls below a certain value while the suspended load is being rolled up and the steady rest control does not function, the suspended load may suddenly start to swing. It is necessary to work while paying attention to the above, which places a heavy burden on the operator.

An object of the present invention is to provide a steady rest control device for a construction machine capable of recognizing a state in which a rope length is equal to or less than a predetermined value without placing a burden on an operator.

[0010]

FIG. 1 shows an embodiment of the present invention.
Referring to FIG. 3, the invention according to claim 1 includes a base 61, an upper swing body 62 provided on the base 61, a swing driving unit 2 for swinging the upper swing body 62, and an upper swing body. An elevating member 63 provided to be able to be raised and lowered at 62, an elevating means 68 for elevating and lowering a suspended load 66 by a hoisting rope 67 wrapped around the elevating member 63, and a suspended load 66 suspended from the tip of the elevating member 63. The vibration suppression that drives the swing driving means 2 to suppress the vibration of the suspended load 66 based on the natural frequency of the suspended load system determined by the weight of the lifting member 63 and the length L of the rope from the tip of the lifting member 63 to the suspended load 66. Means 6 is applied to a steady rest control device of a construction machine provided with a rope length L.
Is generated at a predetermined value L0 determined by the maximum torque of the turning drive means 2.
The above object is achieved by further providing 0, 31.

According to a second aspect of the present invention, the alarm generating means
1 generates an alarm before the rope length L reaches the predetermined value L0. The invention according to claim 3 includes a vibration suppression stop unit that stops driving the vibration suppression unit 6 when the rope length L reaches the predetermined value L0. According to a fourth aspect of the invention, the vibration suppression stopping means gradually stops driving the vibration suppression means 6 before the rope length L reaches the predetermined value L0. The invention of claim 5 is
Before the rope length L reaches the predetermined value L0 or the predetermined value L0
The lifting / lowering stopping means 6 for stopping the driving of the lifting / lowering means 68 when the condition is satisfied is further provided.

According to a sixth aspect of the present invention, there is provided a semiconductor device comprising:
, A swing drive means 2 for swinging and driving the upper swing body 62, an elevating member 63 provided to be able to undulate on the upper swing body 62, and a hoist wound around the elevating member 63. Lifting means 68 for lifting and lowering the suspended load 66 by the rope 67; and a suspended load 6 suspended from the tip of the elevating member 63.
6 based on the weight of the lifting member 63 and the natural frequency of the suspended load 66 defined by the rope length L from the tip of the lifting member 63 to the suspended load 66. The present invention is applied to a steady rest control device for a construction machine having the restraining means 6, and before the rope length L reaches a predetermined value L 0 determined by the maximum torque of the turning drive means 2 or when the rope length L reaches the predetermined value L 0. The above object is achieved by further providing the lifting / lowering stopping means 6 for stopping the driving of the lifting / lowering means 68.

According to the first aspect of the present invention, the vibration suppressing means 6
Drives the swing driving means 2 in the direction in which the swing of the suspended load 66 decreases, but the rope length L becomes a predetermined value L0, and the natural frequency of the suspended load system indicates that the swing of the suspended load 66 When the vibration frequency becomes too large to be reduced even by the above, a warning is issued by the warning generating means 30 and 31.

According to the second aspect of the present invention, an alarm is issued before the rope length L reaches the predetermined value L0. According to the third aspect of the present invention, when the rope length L reaches the predetermined value L0, the vibration suppressing and stopping means stops driving the vibration suppressing means 6, so that the suspended load 66 starts to swing, and the operator can determine the rope length. It can be recognized that the value L has become equal to or less than the predetermined value L0. According to the invention of claim 4, the rope length L is equal to the predetermined value L.
Since the driving of the vibration suppressing means 6 is gradually stopped by the vibration suppressing and stopping means before reaching 0, the suspended load 66 starts to swing gradually, and the operator recognizes that the rope length L has approached the predetermined value L0. can do.

According to the fifth and sixth aspects of the present invention,
Before the rope length L reaches the predetermined value L0 or the predetermined value L0
At this time, since the drive of the lifting / lowering means 68 is stopped by the lifting / lowering stopping means 6, the vibration suppressing effect by the vibration suppressing means can be maintained.

In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used for easy understanding of the present invention. However, the present invention is not limited to this.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION

-First Embodiment- An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a side view showing a configuration of a crane using the steady rest control device according to the first embodiment of the present invention. As shown in FIG. 1, the crane has an upper revolving unit 62 rotatable about a vertical axis on a lower traveling unit 61 as a base. A boom 63 is provided on the upper swing body 62 so as to be able to descend. A sheave 64 is attached to the tip of the boom 63, and a hoisting rope 67 is wound around the sheave 64. The hoisting rope 67 is wound up or fed out by a hoisting drum 68. A hook 65 is attached to the end of the hoisting rope 67.
Hangs a suspended load 66.

FIG. 2 is a hydraulic circuit diagram of the steady rest control device according to the first embodiment. As shown in FIG.
The hydraulic circuit of the steady rest control device according to the embodiment includes a prime mover 100, a hydraulic pump 3 driven by the prime mover 100, a swing motor 2 that is driven to swing by hydraulic oil discharged from the hydraulic pump 3, A turning control valve 1 for controlling the flow of pressure oil supplied from the pump 3 to the turning motor 2, and an operating lever 5 for allowing the operator to input a turning command
And a load fluctuation state detector 9 for detecting a fluctuation state of the suspended load 66.
And a controller 6 for calculating, calculating, and outputting the next output value from the turning command value from the operation lever 5 and the amount of deflection of the load deflection state detector 9, and a command from the controller 6 to the turning control valve 1. It is provided with electromagnetic proportional pressure reducing valves 7A and 7B for converting to pilot pressure, and a pilot hydraulic pressure source 8. The controller 6 is connected to an alarm 30 and an alarm lamp 31, which will be described later.

A rotary encoder 10 for detecting the length of the rope movement for detecting the length from the sheave 64 to the suspended load 66, ie, the rope length L, and a load cell 11 for detecting the current suspended load W are provided. It has.
The rope length L detected based on the signal from the rotary encoder 10 and the hanging load W detected based on the signal from the load cell 11 are used as information for the controller 6 to calculate. To detect the rope length L, the hoisting rope 67 is wound up until the hook 65 contacts the tip of the boom 63, and in this state, the reset switch 12 is turned on, and the pulse counter from the encoder 10 provided on the sheave 64 is counted. Reset in the controller 36 to be performed. Then, by pulling out the hoisting rope 67, the pulse counter is counted up, and the rope length L is detected based on the count value.

As shown in FIG. 1, the swing torque of the crane is determined by the pressure acting on the swing motor 2, and the pressure is controlled by the swing control valve 1. Further, the upper limit of the pressure is limited by the relief valve 4, whereby the turning torque of the crane is limited by the set value of the relief valve 4.

FIG. 3 is a block diagram for explaining the processing performed in the controller 6. As shown in FIG. 3, the controller 6 determines a gain K (described later) based on the detected rope length L and the detected hanging load W.
And an output calculator 13 for outputting a signal for controlling the opening of the electromagnetic proportional pressure-reducing valves 7A and 7B based on the deflection angle θ and the gain K from the load deflection state detector 9. A comparator 14 for comparing the rope length L with a predetermined rope length L0, and an alarm 30 for giving an alarm by voice when L <L0 based on the comparison result by the comparator 14. An alarm lamp 31 for giving an alarm by light is provided.

Next, the operation of the first embodiment will be described. When rotating the upper revolving unit 62, the operation lever 5 is switched to the direction a or the direction b to open the electromagnetic proportional pressure reducing valve 7A or 7B, and the hydraulic oil from the pilot hydraulic source 8 is supplied to the pilot port of the direction control valve 1. 1A or 1
B, and switches the direction control valve 1 to the b position or the a position. As a result, the pressure oil from the hydraulic pump 3 is supplied to the swing motor 2 via the direction control valve 1 and the swing motor 2
Rotates, and the upper swing body 62 swings.

On the other hand, when the hoist drum 68 is driven and the hoist rope 67 is wound, the suspended load 66 rises. When the upper swing body 62 is turned while performing the work of winding up the suspended load 66, the suspended load 66 swings. Here, in the present embodiment, based on the gain K obtained in the gain-function generator 12 based on the rope length L and the suspended load W, and the deflection angle θ of the suspended load 66,
The output calculator 13 outputs a control signal for controlling the electromagnetic proportional pressure-reducing valves 7A and 7B, and changes the opening of the electromagnetic proportional pressure-reducing valves 7A and 7B so as to reduce the swing of the suspended load 66 so that the swing motor 2 is controlled. The upper revolving unit 62 is rotated by driving.

Here, as shown in the above formulas (1) and (2), when the suspended load W is small, the mass of the hoisting rope 67 cannot be ignored and the suspended load 66 is considered as a pendulum. The center of gravity moves to the fulcrum side, that is, the tip side of the boom 63. For this reason, the natural frequency of the suspended load 66 decreases and the swing cycle increases. Conversely, when the suspended load W is large,
Since the mass of the hoisting rope 67 can be ignored, the center of gravity of the pendulum moves to the vicinity of the suspended load 66, the natural frequency of the suspended load 66 decreases, and the swing period increases. Therefore, an increase in the suspended load W is equivalent to an increase in the length of the hoisting rope 67. When the length of the hoisting rope 67 is increased, the natural frequency decreases and the swing period increases. That is, when the hoisting rope 67 becomes longer and the moment of inertia of the suspended load 66 becomes larger, a large amount of operation is required. As described above, the motion characteristics such as the natural frequency when the suspended load 66 swings are affected by the fluctuation of the rope length L of the hoisting rope 67.

Here, the relationship between the rope length L and the swing of the suspended load 66 will be described. In order to suppress the swing of the suspended load 66, it is necessary to control the opening of the electromagnetic proportional pressure reducing valves 7A and 7B by the swing angle θ and an appropriate gain K. FIG. 4 shows the relationship between the rope length L and the gain K. As shown in FIG. 4, the gain K increases as the rope length L decreases, and the gain K decreases as the rope length L increases. This value is determined by the moment of inertia of the upper swing body 62 (the upper swing body 6).
2 and so on).
Therefore, a large gain K is not required in a region where the rope length L is long and the natural frequency of the suspended load 66 is small, but is large in a region where the rope length L is short and the natural frequency of the suspended load 66 is large. It turns out that K is necessary. That is, when the vibration frequency of the suspended load 66 is small, the response required for the upper swing body 62 itself is sufficient, so that even when the gain K is small, the upper swing body 62 can sufficiently follow and swing. When the frequency of the suspended load 66 is large, the response of the upper swing body 62 itself becomes insufficient,
In order to obtain a satisfactory response, a large gain K is required. In addition, as the suspended load W increases, the relationship between the rope length L and the gain K needs to be changed as shown in FIG.

For this reason, the gain-function generator 12 increases the gain K as the rope length L decreases. However, even if the gain K is set to be large, the output torque of the swing motor 2 is reduced. Since the swing motor 2 is limited by the valve 4, the swing motor 2 cannot rotate with an output torque greater than the torque determined by the relief valve 4. For example, as shown in FIG. 6, when the rope length L is equal to or less than a certain value L0, the torque exceeds the upper limit of the torque by the relief valve 4 of the swing motor 2, and beyond that, the gain K
Even if is increased, the torque of the swing motor 2 cannot be controlled.

Therefore, in this embodiment, the controller 6 detects the rope length L, and when the rope length L reaches a predetermined value L0, an alarm is issued from the alarm device 30 and the alarm lamp 31. This is to inform the operator that the steadying control of the suspended load 66 cannot be performed. Therefore, when the alarm is issued, the operator can recognize that the steadying control of the suspended load 66 is not functioning,
As a result, the hoisting rope 67 can be paid out and attention can be given to the operation, so that it is not necessary to perform the operation while observing the length of the rope, and the labor of the operator can be reduced.

Second Embodiment In the first embodiment, an alarm is issued from the alarm 30 and the alarm lamp 31 when the rope length L becomes equal to or less than a predetermined value L0. But the rope length L
Becomes L1 shown in FIG. 6 and approaches the predetermined value L0.
An alarm may be issued from the alarm 30 and the alarm lamp 31. Thereby, the operator can recognize that the rope length L approaches L0 and the anti-sway control will soon stop functioning.

In this case, the color of the alarm sound of the alarm 30 or the color of the lamp of the alarm lamp 31 differs between when the rope length L becomes L0 and when it becomes L1. The operator can easily recognize the difference. In the first and second embodiments, an alarm is issued by both the alarm 30 and the alarm lamp 31. However, an alarm may be issued from one of the alarm 30 and the alarm lamp 31. .

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. As shown in FIG. 7, in the third embodiment, between the output value calculator 13 and the electromagnetic proportional pressure-reducing valves 7A and 7B, when the rope length L <L0, it opens, and L ≧ L.
A switch 16 is provided that closes when it reaches 0. In the first embodiment, an alarm is issued by the alarm device 30 and the alarm lamp 31 when the rope length L becomes L0, but when the rope length L becomes L0. Then, the switch 16 shown in FIG. 3 is turned off, the output of the gain K is stopped, and the steady rest control is stopped. As a result, when the rope length L becomes L0 and the steadying control does not function, the suspended load 66 starts to swing, so that the operator can recognize that the steadying control cannot be performed. Therefore, since the hoisting rope 67 can be paid out and attention can be paid to the operation, there is no need to perform the operation while observing the rope length, and the labor of the operator can be reduced.

In the third embodiment, when the rope length L becomes L0, not only the anti-sway control is stopped, but also as in the first or second embodiment. , The alarm 30 and the alarm lamp 31 may issue an alarm.

Fourth Embodiment In the third embodiment, the anti-sway control is stopped when the rope length L becomes equal to or less than a predetermined value L0. The anti-sway control may be gradually stopped before reaching L1 and reaching the predetermined value L0. FIG. 8 is a block diagram for explaining processing performed in the controller 6 according to the fourth embodiment. As shown in FIG. 8, in the fourth embodiment, a table 17 representing a coefficient R gradually decreasing from 1 to zero as the rope length L changes from L1 to L0, and an output value calculator 13
Multiplier which multiplies the control signal output from by the coefficient R
And the value of the control signal is changed from L1 to L0
, Gradually decrease as it goes to
The opening of A and 7B is gradually reduced. As a result, the anti-sway control by turning of the upper turning body 62 gradually stops functioning from the time when the rope length L becomes L1, and the suspended load 6
6 will gradually swing out. For this reason, the operator can sense the swing of the suspended load 66 and recognize that the anti-sway control is not functioning soon, and the operator can pay out the hoisting rope 67 or call attention to the operation.
There is no need to work while observing the rope length,
The labor of the operator can be reduced.

In the fourth embodiment, when the rope length L becomes L0, not only is the anti-sway control stopped, but also as in the first or second embodiment. , The alarm 30 and the alarm lamp 31 may issue an alarm.

Fifth Embodiment In the fourth embodiment, the anti-sway control is stopped when the rope length L becomes equal to or less than a predetermined value L0. May be stopped. As shown in FIG. 9, the on-off valve 19 for closing the hoist circuit or the hoist pilot circuit may be driven by the output of the comparator 14. As a result, when the rope length L becomes equal to or less than the predetermined value L0 and the anti-sway control stops functioning, the winding of the hoisting rope 67 stops, so that the operator cannot perform the anti-sway control. To pay attention to the operation of paying out the hoisting rope 67 and obviating the need to perform the work while observing the rope length, thereby reducing the operator's labor. . Further, the winding of the hoisting rope 67 may be stopped when the rope length L is a predetermined value L1 (> L0).

In the fifth embodiment, when the rope length L becomes L0, not only the winding of the hoisting rope 67 is stopped, but also the first or second embodiment. As described above, an alarm may be issued by the alarm device 30 and the alarm lamp 31.

In the correspondence between the above-described embodiment and the claims, the turning motor 2 is a turning driving means, the boom 63 is a raising member, the controller 6 is a vibration suppressing means and a lifting / lowering stopping means, the alarm 30 and the alarm lamp. 31 constitutes an alarm generating means, and the hoisting drum 68 constitutes an elevating means.

[0037]

As described above in detail, according to the first aspect of the present invention, the rope length is shortened, and the natural frequency of the load system is reduced by the swing drive means driven by the swing driving means. When the value becomes too large to be impossible, an alarm is issued by the alarm generating means, so that the operator can recognize from the alarm that the suspension control of the suspended load has become inoperative, and the turning drive can be performed. The lifting means can be driven to such an extent that the swinging of the suspended load can be reduced by the means so that the rope length L can be increased. As a result, it is not necessary to perform the operation while observing the length of the rope, and the labor of the operator can be reduced.

According to the second aspect of the present invention, since the warning is issued from the warning generating means before the rope length reaches the predetermined value, the operator can quickly control the anti-sway control because the rope length approaches the predetermined value. You can recognize that it will not be. According to the third aspect of the present invention, when the rope length becomes short and the natural frequency of the load system becomes a large value such that the swing of the load cannot be reduced even by the driving of the turning drive means, the vibration is suppressed. The driving of the vibration suppressing means is stopped by the stopping means. Accordingly, in a situation where the vibration cannot be suppressed by the vibration suppressing unit, useless vibration control is prevented from being performed. According to the invention of claim 4, since the vibration suppressing means is gradually stopped by the vibration suppressing and stopping means before the rope length becomes the predetermined value, the anti-sway control makes the rope length equal to the predetermined value. Before long, it stops functioning, and the suspended load starts to swing out gradually. For this reason, the operator can sense the swing of the suspended load and recognize that it is not possible to perform the anti-sway control soon, and then pull out the rope or call attention to the operation. It is no longer necessary to work while observing, and the labor of the operator can be reduced.

According to the fifth and sixth aspects of the present invention,
Before the rope length reaches a predetermined value or when the rope length reaches a predetermined value, the drive of the elevating means is stopped, so that the operator can recognize that the steady rest control cannot be performed, Since the rope is paid out and attention is given to the operation, it is not necessary to perform the operation while observing the length of the rope, so that the labor of the operator can be reduced.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of a crane using a steady rest control device according to a first embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of the steady rest control device according to the first embodiment;

FIG. 3 is a block diagram for explaining processing performed in a controller 6 according to the first embodiment;

FIG. 4 is a graph showing a relationship between a rope length L and a gain K;

FIG. 5 is a graph showing a relationship between a rope length L and a gain K;

FIG. 6 is a graph showing a relationship between a rope length L and a gain K;

FIG. 7 is a block diagram for explaining processing performed in a controller according to a third embodiment;

FIG. 8 is a block diagram for explaining processing performed in a controller according to a fourth embodiment;

FIG. 9 is a block diagram for explaining processing performed in a controller according to a fifth embodiment;

[Description of Signs] 1 Swivel control valve 2 Swing motor 3 Hydraulic pump 4 Relief valve 5 Operation lever 6 Controller 7A, 7B Electromagnetic proportional pressure reducing valve 8 Pilot hydraulic power source 9 Load fluctuation state detector 10 Rotary encoder 11 Load cell 30 Alarm 31 Warning Lamp 61 Lower Traveling Structure 62 Upper Revolving Structure 63 Boom 64 Sheave 65 Hook 66 Suspended Load 67 Hoisting Rope 68 Lifting Means

Claims (6)

[Claims] 1. A base, an upper revolving body provided on the base, a revolving drive means for revolving the upper revolving body, an elevating member provided on the upper revolving body so as to be able to undulate, and the elevating member Lifting means for raising and lowering a suspended load by a rope wound around the rope, a suspended load determined by the weight of the suspended load suspended from the tip of the lifting member and the length of the rope from the distal end of the lifting member to the suspended load. A vibration suppression means for driving the turning drive means to suppress the vibration of the suspended load based on a natural frequency of the system. An anti-vibration control device for a construction machine, further comprising an alarm generating means for generating an alarm when a predetermined value determined by the maximum torque of the means is reached. 2. The steady rest control device for a construction machine according to claim 1, wherein the warning generating means generates a warning before the rope length reaches the predetermined value. 3. The apparatus according to claim 1, further comprising a vibration suppression stopping means for stopping driving of said vibration suppressing means when said rope length reaches said predetermined value.
A steady rest control device for a construction machine according to the above. 4. The vibration suppression stopping means according to claim 1, wherein the driving of the vibration suppression means is gradually stopped before the rope length reaches the predetermined value.
A steady rest control device for a construction machine according to the above. 5. The apparatus according to claim 1, further comprising an elevating and stopping means for stopping the driving of the elevating means before or when the rope length reaches the predetermined value. The steady rest control device for a construction machine according to any one of claims 4 to 4. 6. A base, an upper swing body provided on the base, a swing drive means for swinging the upper swing body, an elevating member provided to be able to undulate on the upper swing body, and the elevating member Lifting means for raising and lowering the suspended load by a rope wound around the rope, a suspended load determined by the weight of the suspended load suspended from the tip of the lifting member and the length of the rope from the distal end of the lifting member to the suspended load. A vibration suppression means for driving the turning drive means to suppress the vibration of the suspended load based on a natural frequency of the system, wherein the rope length is the turning drive means. And a lifting / lowering stopping means for stopping the driving of the lifting / lowering means before or at a predetermined value determined by the maximum torque of the construction machine.