JPH08157181A - Swing prevention control method of crane - Google Patents

Abstract

PURPOSE: To carry a suspending cargo without vibrating it in a pendulum shape. CONSTITUTION: A suspending cargo 6 is suspended by a hook on the lower end of a wire 4 delivered from a crane main body 2, and the suspending cargo 6 is carried when the crane main body 2 travels. At start time, it is accelerated at acceleration (a), and when constant speed Vmax is attained, it travels at constant speed, and at stopping time, it stops by being decelerated at deceleration (a). An acceleration-deceleration value (a) is found by applying a distance L up to the center of gravity of the suspending cargo 6 from a wire upper fulcrum to an expression [a=f.V0 (1/L)<1/2> (here, (f) is a coefficient, and V0 is initial speed)] derived on condition that the suspending cargo 6 is not swung.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a steady rest of a crane, and when the traveling crane is decelerated and stopped, the suspended load is prevented from swinging or the stopped crane is stopped. This is a method of controlling so that the suspended load does not shake at the time point when the vehicle starts traveling and shifts from the acceleration state to the constant speed state. In order to perform the above control, in the present invention, the distance from the crane main body to the center of gravity of the suspended load, that is, the distance from the crane main body to the hanging device (hook or the like) and the distance from the hanging device to the center of gravity of the suspended load are added. Consider the distance to accelerate or decelerate the crane.

[0002]

Cranes are used to transport containers and construction equipment. FIG. 8 shows an outline of the automatic crane. In this automatic crane 1, a crane main body 2 travels along a rail 3, and a suspended load 6 is suspended by a hook 5 provided at the lower end of a wire 4 fed from the crane main body 2.

In the conventional automatic crane 1 as described above, the traveling speed of the crane body 1 is controlled by fuzzy control in order to suppress the swing (pendulum-like vibration) of the suspended load 6 during transportation. In this fuzzy control, the position of the suspended load 6 during transportation is sequentially detected, and the traveling speed of the crane main body is controlled so as to stop the swing of the suspended load 6 using fuzzy reasoning. Further, in order to detect the position of the suspended load 6, the following two methods have been used.

The first method for detecting the position of the suspended load 6 is to detect the position of the suspended load 6 by attaching a camera to the crane body 2 and processing the image of the suspended load 6 captured by the camera. is there.

The second method of detecting the suspended load position is to detect the pay-out length of the wire 4 by an encoder or the like, and also detect the angle of the wire 4 with respect to the perpendicular by an angle sensor, and detect the wire length and wire angle from the detected wire length. This is a method of detecting the position of the load 6.

[0006]

By the way, in the above-mentioned prior art, it is detected that the hanging load 6 is shaken and the control is performed so as to suppress the shake. In other words,
The control is merely how to stop the swinging load 6, which is swinging, and does not control so that pendulum-like vibration does not occur from the beginning. Therefore, in the past, pendulum-like vibration has occurred.

Further, when detecting the position of the suspended load 6 by image processing, it is necessary to change the focus of the camera according to the ascending / descending position of the suspended load 6, and even if the position of the suspended load 6 is detected by the pattern matching method. However, there is a problem that the pattern is enlarged / reduced by the lifting and lowering of the suspended load 6 and the matching cannot be obtained properly.

When detecting the suspended load position by obtaining the wire length and the wire angle by the sensor, it is necessary to remove the sensor during maintenance. However, because a sensitive angle sensor that can detect even a slight angle is used, it is necessary to be careful when removing the angle sensor, and in some cases the angle sensor may be destroyed. There is. Since the drum for winding the wire 4 is immediately below the rail 3 and is hard to reach, it is difficult to perform delicate work in such a place.

In view of the above-mentioned prior art, the present invention provides a steady rest control method for a crane, which can carry a suspended load of the crane without oscillating like a pendulum without using a difficult-to-handle sensor. To aim.

[0010]

The structure of the present invention for achieving the above object is to suspend a suspended load by a suspending tool provided at the lower end of a wire fed from the crane body, and allow the crane body to travel in this state. In the steady rest control method of a crane that conveys suspended loads, the stopped crane body is accelerated at a constant acceleration, and when the set speed is reached, the crane is driven at a constant speed and decelerated at a constant deceleration when stopped. Then, the distance L ₁ from the upper fulcrum position of the wire to the lower end position of the hanger is detected, and the distance L ₂ from the lower end position of the hanger to the center of gravity of the suspended load and the distance L ₁ are added. A method for controlling a steady rest of a crane, characterized in that a distance L is obtained, and the acceleration and deceleration values are set to acceleration / deceleration values obtained by the following equation (1).

[Equation 2]

Further, in the configuration of the present invention, the value of the coefficient f is 0.
It is characterized by being 608 ± 0.1.

[0012]

In the present invention, the values of acceleration and deceleration are calculated by the formula (1)
Since the acceleration / deceleration value a obtained in step 1 is used, the suspended load does not swing like a pendulum. Expression (1) is an acceleration / deceleration value at which pendulum-like vibration does not occur, and is derived from experimental data. The optimum value of the coefficient f was found to be 0.608 ± 0.1 by experiments.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. Note that the parts performing the same functions as those of the prior art are denoted by the same reference numerals.

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG.
FIG. 3 is a system configuration diagram of a control system of the embodiment. The crane main body 2 of the automatic crane 1 is powered by a cable reel type or curtain reel type cable (not shown) and travels along the rail 3. The crane main body 1 hangs and suspends a suspended load 6 with a hook 5 provided at the lower end of a wire 4. In this embodiment, a large number of suspended loads 6 having the same shape and size are repeatedly transported along the same route.

The crane main body 2 includes an on-board sequencer 1
0, a servo controller 11, a traveling motor 12, a traveling position detection sensor 13, a rotary encoder 14, a wireless communication device 15, a drum, a lifting motor, and the like. The traveling position detection sensor 13 is a sensor that detects where the crane body 2 is located on the traveling route of the rail 3, and specifically, a potentiometer, a synchro, a combination of a limit switch and a dog, and a proximity sensor. A combination of a sensor and a proximity member is used. Further, the rotary encoder 14 outputs a signal according to the rotation of the drum, and based on the signal output of the rotary encoder 14,
The distance L ₁ from the upper fulcrum position of the wire 4 (position extended from the drum) to the lower end of the hook 5 is obtained.
Furthermore, the distance L ₂ from the lower end of the hook 5 to the center of gravity of the suspended load 6 is preset in the onboard sequencer 10.
As described above, in the present embodiment, since the shape and size of the suspended load 6 are fixed, the distance L ₂ can be set in advance.

A wireless communication device 20, a sequencer 21, a computer 22 and a destination input terminal 23 are provided at positions distant from the crane body 2. The wireless communication device 20 and the wireless communication device 15 send and receive data described below using radio waves or light. When the wireless communication devices 15 and 20 are not used, data transmission is performed using a trolley.

Further, as other methods for transmitting data, there are the following methods. A method of connecting with a solid line and winding extra cable with a cable reel when moving. A method of connecting with a solid wire and hanging an extra cable with a cable hook. A method of connecting with an optical fiber cable and winding up an extra optical fiber with a cable reel when moving. A method of connecting with an optical fiber cable and hanging excess optical fiber with a cable hook.

Here, the control operation during traveling of this embodiment will be described with reference to FIGS. 3 and 4.

First, the on-board sequencer 10 detects the current position x _{1 of the} crane body 2 based on the signal from the traveling position detection sensor 13.
Enter The current position x ₁ is the wireless communication device 15, 2
0 and the sequencer 21 to take in the computer 22.

The destination position x ₄ input from the destination input terminal 23 is transferred to the computer 22 via the sequencer 21.
Is taken into. Further, the distance L ₁ detected by the rotary encoder 14 and the set distance L ₂ are taken into the computer 22 via the on-board sequencer 10, the wireless communication devices 15 and 20, and the sequencer 21.

The computer 22 will be described in detail later, but
Based on the data of the distances L ₁ and L _2, etc., an acceleration / deceleration value a that can accelerate / decelerate the suspended load 6 without swinging like a pendulum is obtained by the formula described later. Also, the deceleration start position x ₃ is calculated. Then, the control data such as the acceleration / deceleration value a and the deceleration start position x ₃ obtained by the computer 22 are sent to the on-board sequencer 10 via the sequencer 21 and the wireless communication devices 20, 15.

The on-board sequencer 10 controls the speed of the traveling motor 12 based on the control data, and as shown in FIG.
From the current position x ₁ to the acceleration end position x ₂ , acceleration is performed at the value of the acceleration a, and from the acceleration end position x ₂ to the deceleration start position x ₃ , the vehicle is driven at a constant speed (maximum speed) Vmax to start deceleration. From the position x ₃ to the destination position x ₄ , the speed is decelerated at the value of the deceleration a and stopped at the destination position x ₄ . The speed control of the traveling motor 12 is performed by inverter control. Note that brake control can also be performed during deceleration.

As will be described later, the value of the acceleration / deceleration value a is set to such a value that the suspended load 6 can be accelerated / decelerated without swinging like a pendulum. Therefore, as shown in FIG. 6
Does not swing repeatedly like a pendulum. Figure 4
As shown in (a), the wire 4 is inclined with respect to the vertical line at the time of acceleration, but the wire 4 becomes closer to the position x _2.
Becomes smaller, and when the position x ₂ is reached, the wire 4 becomes vertical. Although oblique to the wire 4 is perpendicular to the deceleration as shown in FIG. 4 (a), the position x ₄
The angle of inclination of the wire 4 becomes smaller as
_When it reaches ₄ , wire 4 becomes vertical. Position x of course
Between the position ₂ and the position x ₃ , the wire 4
Becomes vertical.

When the crane body 2 arrives at the destination position x ₄ , an arrival command is sent from the onboard sequencer 10 to the wireless communication device 1.
Computer 22 via 5, 20 and sequencer 21
Sent to

When an emergency stop command is sent from the sequencer 21 to the on-board sequencer 10 during traveling,
It decelerates at the value of deceleration a and makes an emergency stop.

Here, the calculation in the computer 22 will be described in detail. First, the computer 22 adds the distance L ₁ and the distance L ₂ to obtain the distance L from the upper support position of the wire 4 to the center of gravity of the suspended load 6. Next, the computer 22 uses the following equation (1)
The acceleration / deceleration value a [m / s ² ] is calculated by using.

[0027]

(Equation 3)

It is necessary to reach the maximum speed Vmax.
Distance X₁To calculate. Destination position x _FourDistance is above distance
Distance X₁Is shorter than the destination position x_FourMove to
Calculate the maximum speed that can be traveled without shaking the suspended load 6
Redo. Also, from the degree of deceleration, the deceleration start position x₃Seeking
Meru. Note that V₀= V₂-V₁And V during acceleration₁=
0, V₂= V_maxSo V₀= V_maxAnd slow down
Sometimes V₁= V_max, V₂= 0, so V₀= -V
_maxBecomes

The above equation (1) shows that when the crane main body 2 is subjected to constant velocity linear motion and constant acceleration motion by an experiment,
It is obtained from the condition when the pendulum can no longer swing. The value of the coefficient f is 0.608 ± 0.1 depending on the experiment.
Has been found to be optimal.

FIG. 5 shows experimental data when the suspended load 6 does not swing like a pendulum, and the vertical axis shows the acceleration a [m
/ S ² ], and the horizontal axis is the distance L from the upper fulcrum position of the wire 4 to the center of gravity of the suspended load 6. In this data, the value of the coefficient f is 0.608.

In FIG. 6, the acceleration a is -0.032 [m /
s ² ] and the distance L is 2.5 [m], the experimental data showing the position of the suspended load 6 and the position of the crane body 2,
At this time, the hanging load 6 did not swing.

In FIG. 7, the acceleration a is -0.070 [m /
s ² ] and the distance L is 2.5 [m], the experimental data showing the position of the suspended load 6 and the position of the crane body 2,
At this time, the suspended load 6 swings.

As described above, in this embodiment, since the acceleration / deceleration value a is obtained by the equation (1) for acceleration and deceleration, the suspended load 6 does not swing like a pendulum. Therefore, there is no concern that the suspended load 6 will collide with other objects. Further, since the acceleration / deceleration is performed with uniform acceleration, the distance to stop can be easily obtained, and the vehicle can accurately stop at the target movement position x ₄ . Moreover, an angle sensor and an image processing device are unnecessary.

In the above-mentioned embodiment, since the shape and dimensions of the suspended load 6 are fixed, the distance L ₂ is set as a fixed value in the on-board sequencer 10. However, (a) the object to be conveyed is several patterns. If you can divide, create a data table,
Depending on the suspended load 6 at that time, the operator can select it at the time of transportation, read the label with a bar code reader and inspect the pattern from the data table, or read the data table from the ID device and inspect the pattern from the data table. If the distance L ₂ is set or (b) the object to be conveyed cannot be limited, the operator inputs the distance L ₂ according to the suspended load 6 at that time.

Further, the acceleration / deceleration value a calculated using the equation (1)
May be stored in a recording medium (ROM, RAM, hard disk, floppy disk, optical disk, etc.), and this traveling data may be read out during traveling of the crane to control traveling.

[0036]

According to the present invention as described in detail with reference to the embodiments, the distance L is applied to the equation (1) derived on the condition that the suspended load does not swing like a pendulum, and the acceleration / deceleration is applied. Value a
And the acceleration and deceleration values are used as acceleration / deceleration values a to accelerate and decelerate, the suspended load does not swing like a pendulum, and the safety of the crane is improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a system configuration diagram showing a control system of the embodiment.

FIG. 3 is an explanatory diagram showing a signal transmission state during a control operation of the embodiment.

FIG. 4 is an explanatory diagram showing a traveling operation during control of the embodiment.

FIG. 5 is a characteristic diagram showing experimental data for examining the relationship between distance and acceleration.

FIG. 6 is a characteristic diagram showing a positional relationship between a suspended load and a crane body.

FIG. 7 is a characteristic diagram showing a positional relationship between a suspended load and a crane body.

FIG. 8 is a configuration diagram showing an automatic crane.

[Explanation of symbols]

 1 Automatic Crane 2 Crane Main Body 3 Rail 4 Wire 5 Hook 6 Suspended Load 10 On-board Sequencer 11 Servo Controller 12 Travel Motor 13 Travel Position Detection Sensor 14 Rotary Encoder 15 Wireless Communication Device 20 Wireless Communication Device 21 Sequencer 22 Computer 23 Destination Input Terminal

Claims (2)

[Claims] 1. A steady rest control method for a crane in which a suspended load is hung by a lifting tool provided at a lower end of a wire unwound from the crane main body, and the crane main body is caused to travel in this state to stop the suspension. The crane itself was accelerated at a constant acceleration, and when it reached the set speed, it was run at a constant speed at a constant speed, and when stopped, it was decelerated at a constant deceleration to stop. The distance L ₁ to the lower end position is detected, the distance L ₂ from the lower end position of the hanger to the center of gravity of the suspended load and the distance L ₁ is calculated, and the values of the acceleration and the deceleration are calculated. And a steady rest control method for a crane, wherein the acceleration / deceleration value obtained by the following equation (1) is used. [Equation 1] 2. The steady rest control method for a crane according to claim 1, wherein the value of the coefficient f is 0.608 ± 0.1.