JP2009083977A - Swing prevention control method and swing prevention control system for crane - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a swing prevention control method and a swing prevention control system for a crane, excellent in effect of suppressing swing of a suspended cargo at a turning end point, including swing in a radial direction. <P>SOLUTION: A jib is turned at a constant turning radius, in the order of an acceleration section, a constant speed section, and a deceleration section. Operating times of the acceleration section and the deceleration section are the same, and are set to be approximately the integral multiple of a cycle To of pendular movement of the suspended cargo. A time difference from an end point of the acceleration section to a point of the first maximum swing displacement by oscillation in the radial direction of the suspended cargo generated by a centrifugal force is "(Δ/2)*To", and an operating time of the constant speed section is set to be "(n+Δ)*To" (n: an integer of 0 or more). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an anti-sway control method and an anti-sway control system for stopping a swing of a suspended load that occurs when a crane turns.

  If the crane is swung while the suspended load is suspended by a wire, the suspended load will swing due to the pendulum movement. Especially when a large tower crane is used for dam construction, the turning radius and the suspended length may be set large. Since the amount of vibration is large, the degree of the vibration becomes large, and the crane operation for suppressing the vibration at the end of the turn requires a skill that is skilled for the operator.

Patent document 1 is mentioned as an example of the prior art which made this problem a subject. As described in paragraph [0007] of the same document, the technique described in Patent Document 1 is based on the period of the pendulum motion based on the suspension length of the wire at the start of acceleration and the suspension length of the wire at the end of acceleration. By rotating the boom while accelerating it for a time that is approximately an integral multiple of the average value of the period of the pendulum motion based on it, and moving it at a constant speed after the end of acceleration, the upper fulcrum of the wire and the suspended load are moved at a constant speed. As described in paragraph [0009], the movement of the suspended load is suppressed, and based on the period of the pendulum movement based on the suspension length of the wire at the start of deceleration and the suspension length of the wire at the end of deceleration, as described in paragraph [0009]. The boom is rotated while decelerating for a time that is approximately an integral multiple of the average value of the period of the pendulum movement, and is stopped after the deceleration is completed, so that the suspended load is stopped at the destination without swinging.
Japanese Patent No. 3224191

  When the crane is turned, centrifugal force is applied to the suspended load. Therefore, the swing of the suspended load is a combination of the circumferential deflection and the radial deflection, and the suspended load moves in a substantially elliptical path. To do.

  However, the technique of Patent Document 1 does not consider the centrifugal force acting on the suspended load, that is, the problem of radial deflection, and is a technique that focuses on only the circumferential speed change, that is, acceleration. When the crane turns and radial swing occurs in the suspended load, the technique of Patent Document 1 may not be able to expect a predetermined swing suppression effect at the destination point.

  The present invention was created in order to solve such a problem. A crane steady-state control method and a steady rest that are excellent in the effect of suppressing the swing of a suspended load at a turning end point in consideration of radial deflection. It aims to provide a control system.

  In order to solve the above-mentioned problems, the present invention is a crane for carrying a suspended load that is revolved by turning a jib and hung with a wire. The operation time of the section and the deceleration section is the same time as each other, and is set to a substantially integer multiple of the period To of the suspended load's pendulum motion, and the radial direction of the suspended load caused by centrifugal force from the end of the acceleration section The time difference until the first maximum deflection displacement due to the vibration of is set to “(Δ / 2) · To”, and the operation time in the constant velocity section is set to “(n + Δ) · To” (n: integer greater than or equal to 0) Thus, the crane steady-state control method is characterized in that the suspension of suspended loads at the stop point is stopped.

  The present invention also relates to a crane for turning a jib and transporting a suspended load suspended by a wire, and turning the jib in the order of an acceleration section, a constant speed section, and a deceleration section with a constant turning radius to operate the acceleration section and the deceleration section. The time is set to be an integer multiple of the period To of the pendulum motion of the suspended load, which is the same time as each other, and from the end of the acceleration section, the first maximum of the radial vibration of the suspended load caused by the centrifugal force It has a calculation unit that sets the time difference until the deflection displacement to “(Δ / 2) · To” and sets the operation time in the constant velocity section to “(n + Δ) · To” (n: an integer of 0 or more). The feature was a crane steady rest control system.

According to the above-described steady-rest control method and steady-state control system, first, circumferential run-out is suppressed by setting the operation time of the acceleration section and the deceleration section to be approximately an integral multiple of the period To of the pendulum motion of the suspended load. Is done.
In addition, the suspended load generates radial vibrations due to the centrifugal force during acceleration, and the radial displacement at the end of the acceleration section and the radial displacement of the maximum outer deflection width that is first visited in the constant speed section. A time difference (Δ / 2) · To occurs between Therefore, as the operation time of the constant speed section, the time difference (Δ / 2) · To immediately after the acceleration section ends, and the time difference (Δ / 2) · To immediately before the start of the deceleration section provided symmetrically therewith The added time difference Δ · To is minimized, and a time obtained by adding a substantially integer multiple of the period To to this, ie, tp = (n + Δ) · To is set. Since the acceleration in the deceleration zone is set to be the same as that in the acceleration zone, the runout for the time difference (Δ / 2) · To is canceled during the deceleration zone, and the radial runout is suppressed when the suspended load stops. It is done.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in the suppression effect of the swing of the hanging load in the turning completion point, and can shorten the conveyance cycle time of a crane.

  Hereinafter, the form which applied this invention to the tower crane in dam construction is demonstrated. FIGS. 1 and 2 both show an example of the arrangement of a tower crane and ancillary equipment when placing concrete around the dam. FIG. 1 is a side view and FIG. 2 is a plan view. First, the outline of the operation of the tower crane 3 will be described. The ready-mixed concrete carried on the bunker line 1 by the transferer 2 is a bucket 6 (hanging) suspended from the tip of the jib 4 of the tower crane 3 via a wire 5. Transferred).

  After the transfer is completed, the wire 5 is wound up by a predetermined amount, such as several meters, and the bucket 6 is raised, and this is designated as point A. The ascending position of the bucket 6 is made constant, that is, the length of the wire 5 is made constant, the jib 4 is turned with the point A as the turning start point, and the point B located above the dam body 7 is set as the turning end point. . The turning radius R from point A to point B is constant. In FIG. 1, the dam dam body 7 at the initial stage of construction is shown by a solid line, and the dam body 7 gradually formed is shown by a virtual line.

  Then, for example, the wire 5 is wound down from the point B to lower the bucket 6, and the ready-mixed concrete is transferred to the hopper 8 provided at the concrete placing site of the dam dam body 7. After the transfer to the hopper 8 is completed, the operation is reversed, the wire 5 is wound up, the empty bucket 6 is moved from the point B to the point A, the wire 5 is lowered and the bucket 6 is moved from the transfer car 2 Lower to the transfer location. In the operation cycle of the tower crane 3 described above, an object of the present invention is to suppress the swing of the bucket 6 at the point B and the point A immediately after the end of turning.

  FIG. 3 is a block diagram showing the configuration of the steadying control system according to the present invention. The steadying control system includes the following detection means, a calculation unit 17, and an output control unit 18.

“Detecting means for the undulation angle φ and turning radius R of the jib 4”
As a sensor for detecting the undulation angle φ of the jib 4, an angle detector 11 made of a magnetic scale or the like is attached to the base of the jib 4, and an output signal thereof is output to the calculation unit 17. In the calculation unit 17, the turning radius R of the jib 4 is obtained from the length of the jib 4 input in advance and the output signal of the angle detector 11.

“Detecting means for turning angle θ of jib 4”
As a sensor for detecting the turning angle θ of the jib 4, an angle detector 12 including a sensor for counting the pinion gear of the turning electric motor 20 for the jib 4 is attached, and an output signal thereof is output to the calculation unit 17.

"Detection means for turning speed V of jib 4"
As a sensor for detecting the turning speed V of the jib 4, a speed detector 13 made of a tachometer or the like is attached to the turning electric motor 20 of the jib 4, and an output signal thereof is output to the calculation unit 17.

"Detecting means for winding / lowering speed of wire 5"
As a sensor for detecting the winding / lowering speed of the wire 5, a speed detector 15 made of a tachometer or the like is attached to the winding motor 21 of the wire 5, and an output signal thereof is output to the calculation unit 17.

"Detecting means for winding / lowering distance of wire 5"
As a sensor for detecting the winding / lowering distance of the wire 5, a distance detector 16 made of a magnetic scale or the like is attached to the winding motor 21 or the winding / lowering drum of the wire 5, and the output signal is output to the calculation unit 17. Is done.

"Calculation unit 17, output control unit 18"
The calculation part 17 is comprised from CPU and performs each calculation process mentioned later. The output control unit 18 outputs a control signal to each electric motor based on the calculation result of the calculation unit 17.

  Next, the vibration in the radial direction is generated in the bucket 6 due to the centrifugal force during acceleration. The reason why this vibration is suppressed when the bucket 6 reaches the point B from the point A will be described. FIG. 4 is a graph showing a change in the turning peripheral speed of the jib 4 from the point A to the point B, with the vertical axis representing speed and the horizontal axis representing time. The moving section from the A point to the B point of the jib 4 is divided into an acceleration section, a constant speed section, and a deceleration section. In Patent Document 1, the times of the acceleration section and the deceleration section are determined as substantially integral multiples of the period of the pendulum motion of the suspended load, and the values of the turning time and the turning speed in the constant speed section are arbitrary (for example, the paragraph of the same document). In the present invention, the turning speed Vo and the constant speed operation time tp in the constant speed section are obtained by the following method, as described in [0022].

The turning radius of the tip of the jib 4 (the turning radius of the bucket 6) R is obtained by the equation (1).
R = L · cosφ Formula (1)
L: Length of jib 4 φ: Uneven angle of jib 4

The intrinsic angular velocity ω of the pendulum motion of the bucket 6 is
ω = (g / H) ^1/2 Formula (2)
g: Gravity acceleration H: Distance from tip of jib 4 to bucket 6 (pendulum length)
And the period To of the pendulum motion of the bucket 6 is obtained by the equation (3).
To = 2π / ω Equation (3)
In order to eliminate the circumferential deflection of the bucket 6, the operation time of the acceleration zone and the deceleration zone is set to be substantially an integral multiple of the period To of the pendulum motion, and here, the period To obtained by the equation (3) is the acceleration zone, The operation time in the deceleration zone. In addition, as described in, for example, Patent Document 1, it is known that the fluctuation in the circumferential direction is suppressed by setting the operation time in the acceleration zone and the deceleration zone to be substantially an integral multiple of the period To of the pendulum motion. Therefore, the specific description is omitted here.

Next, the turning speed Vo at the tip of the jib 4 is obtained by the equation (4).
Vo = S / {(n + Δ) · To + To} Equation (4)
S: Circumferential travel distance of the tip of the jib 4 from point A to point B n: an integer greater than or equal to 0 Δ: time difference coefficient n is varied within the range of Vo ≦ Va (maximum turning speed of the turning electric motor 20) A turning speed Vo that is an optimum constant speed is determined. Normally, from the viewpoint of shortening the cycle time of the tower crane 3, the turning speed Vo is set to the maximum at Va or less.

By determining the turning speed Vo, the acceleration a in the acceleration section and the deceleration section is
a = Vo / To (5)
Is required.
The constant speed operation time tp is
tp = (n + Δ) · To (6)
Is required.
From the above, the total turning time tt of the jib 4 is
tt = tp + 2To (7)
As determined.

Hereinafter, the time difference coefficient Δ will be described.
Equations (8) and (9) are equations of motion for the bucket 6 during acceleration.

The general solution of equation (8) is x = a (cos ωt−1) / ω ² , and therefore the circumferential speed is dx / dt = − (a · sin ωt) / ω. ω is the intrinsic angular velocity of the pendulum motion. By solving the equation (9) using this, the radial deflection displacement yt _{= To} and the radial velocity (dy / dt) _{t = To} at the end of acceleration are expressed by the equations (10) and (11), respectively. Given.

  Next, using these values, a time difference coefficient Δ / 2 of vibration in the radial direction at the start of the constant velocity section is obtained. The time difference coefficient Δ / 2 can be obtained from the equation (12) regarding Δ. Further, the amplitude A of the vibration in the radial direction is given by Expression (13).

  From the above equations (12) and (13), the above equation (6) regarding the constant speed operation time tp is obtained.

FIG. 5 is a graph showing a change in vibration in the radial direction when the bucket 6 moves from the point A to the point B. The vertical axis represents the radial deflection displacement, and the horizontal axis represents time. FIG. 6 is an explanatory plan view showing a vibration change in the radial direction when the bucket 6 moves from the point A to the point B. 5 and 6, the bucket 6 vibrates with an amplitude A centering on Vo ² / (Rω ² ), and the displacement y when To elapses at the end of the acceleration section is the displacement of the maximum deflection width on the radially outer side. However, it can be seen that it is located inward in the radial direction by a time difference (Δ / 2) · To. That is, the time difference (Δ / 2) · To means the time difference from the end of the acceleration section to the first maximum deflection displacement due to the radial vibration of the suspended load caused by the centrifugal force. Therefore, since this time difference (Δ / 2) · To exists, the vibration in the radial direction cannot be settled at the point B simply by setting the operation time in the constant speed section to an approximately integral multiple of the period To of the pendulum motion.

  On the other hand, in the present invention, the operation time in the constant speed section is the time difference (Δ / 2) · To immediately after the acceleration section ends, and the time immediately before the start of the deceleration section provided symmetrically to cancel this. The time difference Δ · To obtained by adding the time difference (Δ / 2) · To is minimized, and a time obtained by adding a substantially integer multiple of the period To to this time, that is, tp = (n + Δ) · To is set. Since the acceleration in the deceleration zone is set to be the same as that in the acceleration zone, the time difference (Δ / 2) · To will be canceled during the deceleration zone, and the bucket 6 stops at point B. No radial wobbling occurs. 5 and 6 show a case where n = 3.

Hereinafter, operation | movement of the tower crane 3 to which this invention is applied is demonstrated. First, a preparation operation for manually determining a placement position and the like when the tower crane 3 is automatically operated will be described.
When the tower crane 3 is put into an operation start state from an arbitrary position, in FIG. 1, the operator manually operates the turning operation of the jib 4, the raising and lowering operation of the jib 4, and the lowering operation of the wire 5, and the hopper 8 is positioned. Move bucket 6 to point C. This point C becomes the reference position of the turning angle θ and the reference position of the undulation angle φ of the jib 4. Then, with the undulation angle φ of the jib 4 as it is, the jib 4 is turned to above the transfer location from the transfer car 2, the wire 5 is once lowered, and the bucket 6 is positioned at the transfer location from the transfer car 2.

  During this time, the angle at which the jib 4 is turned is detected by the angle detector 12, and the turning angle θ is calculated by the calculation unit 17. Further, the undulation angle φ of the jib 4 is detected by the angle detector 11, and the turning radius R is calculated by the calculation unit 17 based on the formula (1). Thereafter, according to the procedure described using Expression (2) to Expression (13), in the calculation unit 17, the acceleration section and the deceleration section time To of Expression (3) (may be a substantially integer multiple of To), The constant speed turning speed Vo of the equation (4), the acceleration a of the equation (5), the acceleration a of the deceleration region, the constant speed operation time tp of the equation (6), and the total turning time tt of the equation (7) are calculated. The speed graph shown in FIG. 4 is determined.

Next, the automatic operation of the tower crane 3 will be described.
"(1) Winding of the wire 5 on the bunker wire 1"
When a signal indicating that the ready-mixed concrete has been transferred from the transferer 2 to the bucket 6 is received and the operator activates the steadying control system according to the present invention, an output signal is output from the distance detector 16, Based on the arithmetic processing, the wire 5 is wound up until the bucket 6 is located at the point A.

“(2) Jib 4 turns (outward)”
Before and after the bucket 6 reaches the point A, the calculation unit 17 performs calculation processing based on the equations (2) to (13), and first accelerates to the turning speed Vo over time To. The output control unit 18 controls the turning electric motor 20. Then, the output signal of the speed detector 13 is monitored by the arithmetic unit 17, and when the turning speed Vo is reached, the output control unit 18 controls the turning electric motor 20 so as to maintain the turning speed Vo. Since the time of the acceleration section is the pendulum period To (or approximately an integer multiple of the period To), the circumferential vibration of the bucket 6 is removed when the turning speed Vo is reached.

  From the time when the turning speed Vo is reached, after the constant speed operation time tp obtained by the equation (6) has elapsed, the vehicle decelerates at the same acceleration as the acceleration section and stops at the B point. The output control unit 18 controls the turning electric motor 20 so as to stop. Since the constant speed operation time tp is set to (n + Δ) To, the bucket 6 stops at point B without causing elliptical motion. Thereby, the conveyance cycle time of the tower crane 3 can be shortened.

“(3) Lowering of the wire 5 on the hopper 8”
After stopping at the point B, the calculation unit 17 issues a command to lower the wire 5 to the output control unit 18, and the winding motor 21 lowers the wire 5 under the control of the output control unit 18. The output signals from the speed detector 15 and the distance detector 16 are monitored, and when the bucket 6 reaches point C, the winding motor 21 is stopped.

“(4) Release of ready-mixed concrete”
The ready-mixed concrete in the bucket 6 is automatically discharged to the hopper 8, and a signal indicating the completion of the discharge is transmitted to the operator.

“(5) Winding of the wire 5 on the hopper 8”
When the operator activates the steady rest control system in response to the completion signal of the ready-mixed concrete, the operation unit 17 issues a wire 5 winding command to the output control unit 18, and the output control unit 18 controls the winding motor. 21 winds up the wire 5. Output signals from the speed detector 15 and the distance detector 16 are monitored, and when the bucket 6 reaches the point B, the winding motor 21 is stopped.

“(6) Jib 4 turn (return)”
Since the distance H from the tip of the jib 4 to the bucket 6 is not different from the forward path, the output control unit 18 controls the turning electric motor 20 so as to accelerate to the turning speed Vo over time To as in the forward path. To do. Then, the output signal of the speed detector 13 is monitored by the arithmetic unit 17, and when the turning speed Vo is reached, the output control unit 18 controls the turning electric motor 20 so as to maintain the turning speed Vo. When the turning speed Vo is reached, the circumferential deflection of the bucket 6 is removed.

  From the time when the turning speed Vo is reached, after the constant speed operation time tp obtained by the equation (6) has elapsed, the vehicle decelerates at the same acceleration as the acceleration section and stops at the point A. The output control unit 18 controls the turning electric motor 20 so as to stop. At point A, the bucket 6 stops without causing elliptical motion.

"(7) Lowering wire 5, loading fresh concrete"
When the bucket 6 arrives at point A, the operation unit 17 issues a command to lower the wire 5 to the output control unit 18, and the winding motor 21 lowers the wire 5 under the control of the output control unit 18. Output signals from the speed detector 15 and the distance detector 16 are monitored, and the winding motor 21 is stopped when the bucket 6 is positioned at a transfer position from the transfer car 2. The transferer 2 automatically detects the bucket 6 and throws ready-mixed concrete. Then, a signal indicating that the ready-mixed concrete has been transferred from the transfer car 2 to the bucket 6 is transmitted to the operator. Thereafter, the procedures (1) to (7) are repeated.

  In addition, about the determination of positions, such as A point which is a turning start point, B point which is a turning end point, a turning center, it can also be set as the system which inputs 3D coordinate data directly to a computer, for example.

  The preferred embodiments of the present invention have been described above. In the described form, since the length of the wire 5 during turning is constant, the time of the acceleration section and the deceleration section set as the circumferential steady rest is set to be substantially an integral multiple of the period To of the pendulum motion. However, for example, as described in Patent Document 1, when a wire is wound up and down in an acceleration section and a deceleration section, respectively, in the acceleration section, a suspended pendulum based on the suspension length of the wire at the start of acceleration is used. It is approximately an integer multiple of the average value of the period of movement and the period of pendulum movement of the suspended load based on the suspended length of the wire at the end of acceleration. The average value of the pendulum movement period and the period of the pendulum movement of the suspended load based on the suspended length of the wire at the end of deceleration is approximately an integral multiple of the average value. An integer multiple is also included as “substantially an integral multiple of the period To of the pendulum motion”.

It is a side view which shows the example of arrangement | positioning of the tower crane and incidental equipment at the time of placing concrete around a dam. It is a top view which shows the example of arrangement | positioning of the tower crane and incidental equipment at the time of placing concrete around a dam. It is a block diagram of the configuration of the steady rest control system according to the present invention. It is a graph which shows the change of the turning peripheral speed of a jib. It is a graph which shows the vibration change of the radial direction of a suspended load. It is plane explanatory drawing which shows the vibration change of the radial direction of a suspended load.

Explanation of symbols

1 Bunker Line 2 Transfer Car 3 Tower Crane 4 Jib 5 Wire 6 Bucket (Suspended Load)

Claims (2)

In a crane that turns a jib and carries a suspended load suspended by a wire,
Rotate the jib in the order of acceleration section, constant speed section, deceleration section with a constant turning radius,
The operation time of the acceleration section and the deceleration section is the same time as each other, and is set to a substantially integer multiple of the period To of the pendulum motion of the suspended load.
The time difference from the end of the acceleration section to the first maximum deflection displacement due to the radial vibration of the suspended load caused by centrifugal force is defined as “(Δ / 2) · To”, and the operation time of the constant speed section is represented by “( n + Δ) · To ”(n: integer greater than or equal to 0)
A crane steady-state control method, characterized in that suspension of suspended load at a stop point is stopped. In a crane that turns a jib and carries a suspended load suspended by a wire,
Rotate the jib in the order of acceleration section, constant speed section, deceleration section with a constant turning radius,
The operation time of the acceleration section and the deceleration section is the same time as each other, and is set to a substantially integer multiple of the period To of the pendulum motion of the suspended load.
The time difference from the end of the acceleration section to the first maximum deflection displacement due to the radial vibration of the suspended load caused by centrifugal force is defined as “(Δ / 2) · To”, and the operation time of the constant speed section is represented by “( A crane steady-state control system having a calculation unit set to (n + Δ) · To ”(n: an integer equal to or greater than 0).

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