JPS63288892A - Method and device for steadying suspended loads - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is suspended from a moving object such as a trolley by a rope. In this invention, acceleration/deceleration refers to at least one of acceleration and deceleration, and acceleration/deceleration force also refers to acceleration or deceleration. Refers to at least one of acceleration force or deceleration force.

[Conventional technology]

When a suspended load is suspended from a trolley with a rope and the trolley is moved directly above the target position, the suspended load will swing. For this reason,
A trolley running method that does not cause vibration is being studied.

As a method for this, a method has been proposed in Japanese Patent Laid-Open No. 62-41189.

If no force is applied to stop the swing, the suspended load will make a pendulum motion with the swing period shown by the following equation.

Here, ML: ) Weight of the trolley MC: Weight of the suspended load (including hanging equipment): Equivalent rope length as a simple pendulum g: Acceleration of gravity Therefore, the suspended load is stationary directly below the trolley. When a constant acceleration or deceleration force is applied to the trolley from the above-mentioned state, after the swing period T has elapsed, the suspended load is located directly below the trolley, and no swing has occurred.Therefore, the swing period T
By accelerating or decelerating so that the target speed is reached at the target speed, runout can be prevented.

Generally, for container cranes, the target speed is the maximum speed for acceleration and zero for deceleration. The current speed is zero in the case of acceleration, and is the maximum speed in the case of deceleration.

Now, a case will be described in which the equivalent rope length is set constant and the vehicle is accelerated from a stopped state to the maximum speed Vll1ax.

The swing period T is determined by the above equation (1), and then the acceleration force F of the trolley is determined by the following equation. Then, acceleration is performed using this acceleration force F for a period of swing period T.

When stopping the vehicle from running at the maximum speed V+*ax with the equivalent rope length constant, use the deceleration force F obtained from equation (2) during the swing period T obtained from equation (1), It decelerates the speed.

The following explanation will mainly focus on the case of acceleration.

In the case of deceleration, acceleration and acceleration force can be read as deceleration and deceleration force, respectively.

[Problem that the invention seeks to solve]

(A) and (B) in Fig. 4 show the swing period (
In Figure 0, which shows the relationship between the acceleration time (acceleration time) The dashed-dotted line P2 in the area with short length sentences is (1)
Equation, 0 equivalent rope length la which is based on equation (2)
is the equivalent rope length at which the acceleration force F is maximum. The case of deceleration is also similar to this figure.

As described above, since the acceleration force F is inversely proportional to the equivalent rope length, it is necessary to calculate the acceleration force F and the acceleration time T, and to control the acceleration force F, which complicates the apparatus.

In addition, since the acceleration force F is finite, if the equivalent rope length is short (that is, shorter than 1la), the swing period T
It is not possible to accelerate to the maximum speed V wax of the target speed only during this period, and it is not possible to stop in the case of deceleration.

Therefore, for an equivalent rope length statement shorter than la,
As shown by the broken line P3 in the figure, the accelerating force F is halved and the deflection is performed twice, so that the acceleration is completed in twice the time of the deflection period T.

In this case, in the case of an equivalent rope length shorter than la, the time will be doubled, resulting in a decrease in cargo handling efficiency. Also,
The driver riding on the trolley feels uncomfortable because the acceleration/deceleration time changes greatly around Jla.

Even in the area where the equivalent rope length is longer than la, the acceleration/deceleration time becomes longer in proportion to the equivalent rope length, resulting in poor cargo handling efficiency.

An object of the present invention is to shorten cargo handling time.

[Means for solving problems]

The above purpose is to apply a predetermined acceleration/deceleration force to the moving body until the moving body reaches a target speed when accelerating or decelerating the movement of a moving body with a load suspended via a rope, and to The acceleration/deceleration force applied to the moving body is set to zero in the middle of each period of swing of the suspended load, and the total time for applying the predetermined acceleration/deceleration force is determined so that the moving body reaches the target when the predetermined acceleration/deceleration force is applied to the moving body. The time taken to reach the speed is the same as Ta, and the length of the period during which the acceleration/deceleration force is zero is equal to each cycle of the swing of the suspended load when accelerated/decelerated by the predetermined acceleration/deceleration force and the acceleration/deceleration force in the field. This can be achieved by setting the size so that the hanging load can be positioned below the vertical line of the moving body at the end of the process.

[For production]

Since the total time for applying the predetermined acceleration/deceleration force is the time Ta, the moving object can reach the target speed. A constant velocity section is provided in the middle of each period of swing of the suspended load, and the size of this section is such that the suspended load is located below the moving body at the end of each period. There is no swinging of the suspended load at the end of the process, which allows the movable body to accelerate or decelerate to the target speed in a short time, and prevents swinging at the end of acceleration/deceleration.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8. FIG. 8 explains the configuration of the trolley.

Hanging load (for example, container) 1 is a roll-up bag on trolley 2! i5
It is suspended via a rope 6 and a hanging tool 7. The hanging load l is hoisted up and lowered by the hoisting device 5. The trolley 2 travels on the girder 11 by a traveling device 10.

An electric braking device (not shown) is installed in the traveling device IO. The operator's cab 15 is suspended from the trolley 2 and moves together with the trolley 2. The operator's cab 15 is equipped with a control device (not shown) for controlling the hoisting device 5 and the traveling device IO.

The trolley 2 is equipped with a weight detector (not shown) that detects the weight MC of the suspended load 1 (including the hanging tool 7). This weight detector detects the current value of a DC motor (not shown) of the hoisting device 5, for example, to detect the weight.

, the trolley 2 is equipped with a rope length detector (not shown) for detecting the hanging length of the rope 6. This rope length detector uses, for example, a rotary encoder that detects rotation of the hoisting device 5 in forward and reverse directions.

In the present invention, the swing of the hanging tool is treated as a simple pendulum motion. For this reason, the equivalent rope length statement refers to the length of the rope whose swing period as a simple pendulum matches the actual swing period. Therefore, the equivalent rope length statement is the rope length detected by the rope length detector. For example, when there is essentially one rope 6 as shown in the figure, the rope length detected by the rope length detector is When there is a hanging load l, the predetermined value is added to the length from the rope hanging position of the trolley 2 to the hanging fixture 7 plus the height of the hanging fixture 7).

The hanging tool 7 is equipped with a hanging load detector for detecting the presence or absence of a hanging load l.

Further, the trolley 2 is equipped with a position detector (not shown) for detecting the current position. The zero position detector is, for example, a rotary encoder that rolls on the girder 11. When the target stop position is input to the control device in the driver's cab 15, the position detector can calculate the deceleration start position.

The weight detector, rope length detector, hanging load detector, and position detector are known. The detection values of these various detectors are input to the control device in the driver's cab 15.

Next, the basics of the steady rest method will be explained.

The following description is based on the following assumptions.

Acceleration means accelerating from a stopped state to maximum speed, and deceleration means stopping from maximum speed. Further, in general, in a crane for loading and unloading a container, it takes about 5 seconds to reach the maximum speed Vmax from a stopped state with the container suspended. In this case, Jla is about 7 m.

Further, the equivalent rope length when running the trolley is about 5 m to 16 m. This minimum length of approximately 5m is 2a/4
Since it is larger than , it is long enough to accelerate to the maximum speed by making two swings.

On the other hand, the maximum length of about 16m is 29. It is slightly longer than a. The same applies to deceleration.

The case of acceleration will be explained below.

When the trolley is accelerated from zero speed with the maximum acceleration force F+sax that the trolley traveling device can generate, the maximum speed Vffial
The standard equivalent rope length a such that the time Ta until reaching t coincides with one period of the simple pendulum is expressed by the following equation.

If the equivalent rope length intersection at the time of starting acceleration is approximately equal to fLa, the maximum acceleration force FmaxlTa is continuously applied for a time to perform acceleration, as in the case of JP-A-62-41189. After a certain period of time, the maximum speed Vmax is reached.

The actual acceleration of the trolley until it reaches the maximum speed V-aX is not constant because it is affected by the swing of the suspended load, and the acceleration decreases particularly in the middle of the acceleration section. This is as described in the above-mentioned Japanese Patent Application Laid-Open No. 62-41189. The same applies when applying deceleration force.

1. Since the traveling device includes a control device that causes the vehicle to travel at a commanded speed, it is difficult to output the maximum acceleration force Fmax at the start of acceleration. Therefore, the target value of the traveling speed during acceleration should be a large positive value (for example, the maximum speed Vma
x) is output to the control device to saturate the speed control system of the control device and perform constant torque control using current limit value control. On the other hand, in the case of deceleration, a large negative value (for example, a value twice the maximum speed) is output as the target value of the traveling speed.

In addition, the method for outputting this maximum acceleration force (maximum deceleration force) Fmax is as follows: When l>fL a, intersection <U
The same applies to case a.

If the equivalent rope length statement at the time of starting acceleration is longer than Aa, proceed as follows.

As shown by the solid line N1 in FIG. 5, first, the maximum acceleration force F w
ax is applied continuously for a time Tl of T a / 2 to perform acceleration, thereby the speed of the trolley is approximately V ff
It will be half of iaw.

Next, the trolley was run for 12 hours with the acceleration force set to zero, but no force was applied to accelerate the trolley, but a force equivalent to the running resistance of the trolley was applied.

The actual speed of the trolley is affected by the suspended load.

The time T2 during which this acceleration force is applied to zero will be described later (5)
Calculate by formula or formula (7). In other words, time T2 is the swing period T of the suspended load based on the actual equivalent rope length and time T.
This is half the difference from a.

Next, the maximum acceleration force F wax is continuously applied again for a time T3 of Ta/2 to perform acceleration.

Since the time for the maximum acceleration force Fmax is Ta time in total, the trolley can reach the maximum Vmax after T3 has elapsed.

In FIG. 5, a dashed-dotted line P1 indicates the conventional average acceleration in the case of the same equivalent rope length as the solid line N1. Similarly, the solid line N1 is also schematically shown. T
A solid line N1 between l and T3 indicates the average acceleration.

The predetermined time T2 will be explained using FIG. 7.

FIG. 7 shows the swing of the suspended load during acceleration and deceleration, with the horizontal axis representing the swing angle and the vertical axis representing the swing speed. When acceleration is started from a stopped state with the maximum acceleration force Fmax, the suspended load that was at point 0 swings from point 0 to point A and point B around point 0'. 0
When the time Tl from the point becomes T a /2 hours (position of point B), acceleration at the maximum acceleration force Fmax is stopped and the vehicle runs at a constant speed.

Then, the suspended load swings from point 0 to point D, which is symmetrical to point B, via point C'. The time from point B to point C' to point D is T2. When the suspended load is located at point D, again,
The suspended load is accelerated at point D and point E for a time T3 of Ta/2 with the maximum acceleration force Fiat.

It swings to 0 points. Acceleration is stopped when the suspended load returns to the zero point, so the swing of the suspended load is eliminated.

Now, in FIG. 7, the angle formed by BOD is half the angle θ formed by BO'D.

Further, when acceleration is performed using equations (1) and (2) as in the conventional case, the time required for the suspended load to make one revolution around the 0' point is T. On the other hand, the time required for 0-A-B and the time required for D-E-0 are each Ta/2, and the time required for B-C'-0 is θ/2. Therefore, the time required for B-C'-D is calculated as shown in the following equation.

On the other hand, the swing period T of the equivalent rope length statement can be expressed by the following equation, using the reference equivalent rope length la as a reference.

According to equations (5) and (6), the following - is obtained.

Therefore, according to this, the time of T2 can be shortened compared to the conventional method. As shown by the solid line N1 in FIG. 4(A), the amount of change in acceleration/deceleration time depending on the equivalent rope length can be reduced.

On the other hand, the acceleration/deceleration force F can be kept constant at the maximum acceleration/deceleration force Fwax as shown by the solid line N1 in FIG. 4(B).

Next, a case where the equivalent rope length statement is shorter than Jla will be explained.

As shown by the solid line N2 in Fig. 6, in this case, there are two deflections, so it is sufficient to perform acceleration' based on the two deflections, that is, as before, with the maximum acceleration force Fmax, the T1 time is Accelerate, run the acceleration force for 12 hours, then accelerate again for 13 hours with the maximum acceleration force Fa + ax,
This is repeated twice as one cycle.

In this case, the target speed (maximum speed V+++ax) in each cycle
It is only necessary to reach half the speed of T when l<la.
l and T3 are half of T1 and T3 when l>la. That is, T1 and T3 in the case of 41<jLa are T a
/ It becomes 4. Similarly, equation (5) becomes the following equation.

In addition, the trolley continuously accelerates with the maximum acceleration force Fmax that it can produce, and at the end of the Ta time, the maximum speed V ll
The equivalent rope length that can obtain 1ax and stop the hanging load from swinging is JLa/4. this"'
fl a/4” is the second standard equivalent rope length Jl
becomes a'. Therefore, equation (6) becomes the following equation.

j・Therefore, equation (7) becomes the following equation.

In this case, the time of 2T2 can be shortened. And the fourth
As shown by the solid line N2 in Figure (A), it is possible to reduce the amount of change in acceleration/deceleration time depending on the equivalent rope length.

On the other hand, the acceleration/deceleration force F can be kept constant at the maximum acceleration force Fmax as shown by the solid line N2 in FIG. 4(B).

In FIG. 6, a dashed-dotted line P3 indicates the conventional average acceleration in the case of the same equivalent rope length as the solid line N2. Similarly, the solid line N2 is also schematically shown. T
A solid line N2 between I and T3 indicates the average acceleration.

The case of acceleration has been described above, but when decelerating from the maximum speed to zero speed, the acceleration, acceleration force, and maximum speed may be replaced with deceleration, deceleration force, and zero speed, respectively.

Next, the overall operation will be explained according to the flowcharts shown in FIGS. 1 to 3.

In FIG. 3, when a lifting operation of the lifting device is commanded, a lifting operation is performed to lift the suspended load to a height at which the trolley can travel (step 510), and when it is lifted to a predetermined height,
The suspended load 4MC is detected by a weight detector, and the equivalent rope length is calculated based on the data from the rope length detector and the suspended load detector. (Step 520) Next, the reference runout period Ta is calculated using the above two detected values Mc and l using the equation (4). Next, using this Ta, the reference equivalent rope length la is calculated using the equation (3). Calculate.

(Step 530) Next, an accelerated driving operation based on FIG. 1 is performed.

(Step 5too) Next, constant speed running operation is performed at the maximum speed Vmax up to the deceleration start position. The deceleration start position can be recognized by the position detector. (Step 3200) Next, use the braking device to
Perform deceleration driving based on the diagram (step S30
0) Next, since the trolley has stopped at the target position and the swinging has substantially stopped as described above, the hanging tool is lowered. (Step 3400) Next, according to FIG. 1, accelerated driving operation (Step 5100)
Explain the details.

First, the equivalent rope length statement and the reference equivalent rope length a are compared. (Step 5101) If the equivalent rope length statement and the standard equivalent rope length jLa are approximately equal, the process moves to step 5ill. The criterion for determining whether or not they are approximately equal is that if the 0 sentence determined by experimental values or the allowable value for shake is larger than Ua, the process moves to step 5121.If the 1 sentence is smaller than ILa, the process moves to step 5141.

If the equivalent rope length statement and the standard equivalent rope length statement a are almost equal, the maximum acceleration force F wax and the reference swing period Ta
(Step S l l 1)
) If the equivalent rope length is greater than the reference equivalent rope length statement a, the maximum acceleration force Fmax is T a / 2 hours T
The driving speed is now approximately Vma.
It becomes half of x. (Step S121) Next, the acceleration force is set to zero. However, the force corresponding to the running of the trolley and P/resistance is output. The time T2 is determined by equation (7) (or equation (5)). (Step 5123) Next, acceleration operation is performed again for T a / 2 hours with the maximum acceleration force F wax, and the traveling speed is now the maximum speed Vm.
It becomes ax. (Step S125) If the equivalent rope length statement is shorter than the reference equivalent rope length Jla, acceleration operation is performed for Ta/4 hours at the maximum acceleration force F wax, and the running speed is now approximately l/ of VIIax. It becomes 4.

(Step 5141) Next, the acceleration force is set to zero. however,
A force corresponding to the running resistance of the trolley is output. That time T
2 is determined by equation (10) (or equation (8)). (Step 3143) Next, once again, the maximum acceleration force F 11ax is T a / 4
Carry out time acceleration driving, now the driving speed is approximately VI
It is half of Ilax. (Step 5145) Next, it is checked whether steps 5141-Si20 have been repeated twice, and if it has been repeated once, steps 5141-5145 are repeated, and now the traveling speed becomes the maximum speed Vmax. (
Step 5147) In addition, if you memorize the 12 hours obtained in step 5143 of the first time,
The calculation of equation (8) in 143 can be made unnecessary.

1>l a, ! In each case of l<fL a, Tl, T2, and T3 are determined through experiments, etc., taking into account the allowable swing of the suspended load when the target speed is reached, the slope of the travel path, the acceleration ability of the trolley, etc. It can be adjusted slightly.

The deceleration running operation in step 3300 is as shown in FIG. Since this is the same as in FIG. 1, the explanation will be omitted. What is necessary is to replace acceleration and acceleration force with deceleration and deceleration force.

In the case of sentence a/4 times sentence a/9, it is sufficient to use the swing of three cycles as a reference, Tl and T3 become Ta/6, and T2 becomes the following equation.

In the above embodiment, when accelerating from a certain speed to a higher target speed, or decelerating from a certain speed to a lower target speed, the "target speed" is the difference between the current speed and the target speed. The difference '° may be taken as the maximum speed V maw.

Although the trolley of the above embodiment has a hoisting device and a traveling device installed on the trolley, the present invention can also be applied to a trolley installed on the girder side. The present invention can also be applied to a crane in which a rope is suspended from the tip of a rotating boom.

〔Effect of the invention〕

According to the present invention, the difference in acceleration/deceleration time due to the difference in equivalent rope length can be reduced, and the cargo handling time can be shortened.

[Brief explanation of the drawing]

FIG. 1 is a flowchart during acceleration of an embodiment of the present invention;
FIG. 2 is a flowchart during deceleration according to an embodiment of the present invention.
Fig. 3 is a flowchart from the start of running to the stop of running according to an embodiment of the present invention, Figs.
The figure shows an acceleration state according to an embodiment of the present invention when the equivalent rope length statement is longer than the reference equivalent rope length jLa, and FIG.
Figure 7 is a diagram showing the relationship between the swing angle and speed of the suspended load during acceleration and deceleration, and Figure 8 is the relationship between the trolley and the suspended load. It is a figure showing a relationship. 1-----1 hanging load, 2----1--) Loli, Figure 13 Figure 4 (A) Figure 4 (B) 5th r2? l O6 bacteria

Claims (1)

[Claims] 1. When accelerating or decelerating the movement of a moving body with a load suspended via a rope, a predetermined acceleration/deceleration force is applied to the moving body until the moving body reaches a target speed, and , the acceleration/deceleration force applied to the moving body is set to zero in the middle of each cycle of swinging of the suspended load during acceleration/deceleration, and the total time for applying the predetermined acceleration/deceleration force is equal to the time when the predetermined acceleration/deceleration force is applied to the moving body. The time Ta for the moving object to reach the target speed is the same, and the length of the period during which the acceleration/deceleration force is zero is the predetermined acceleration/deceleration force and the swing of the suspended load when accelerated/decelerated with the zero acceleration/deceleration force. A method for resting a suspended load, characterized in that the size is such that the suspended load can be positioned below the vertical line of the moving body at the end of each cycle. 2. A method for resting a suspended load according to claim 1, wherein the predetermined acceleration/deceleration force is a maximum acceleration/deceleration force possessed by the moving body. 3. When a predetermined acceleration/deceleration force is applied to a moving body with a suspended load via a rope, find the time Ta until the moving body reaches the target speed, and calculate the time Ta required for the mobile body to reach the target speed. The time T is calculated by dividing the time Ta by 2N, which is twice the number of swings N.
1, a first moving step of applying the predetermined acceleration/deceleration force to the moving body to move the moving body, and then multiplying the swing period T by the actual equivalent rope length l by the number of times N. a second movement step in which the acceleration/deceleration applied to the moving body is made zero with a constant velocity force during a time T2 obtained by dividing the difference between the time NT and the time Ta by the numerical value 2N; a third moving step of applying the predetermined acceleration/deceleration force to the moving body to move the moving body; and repeating the first to third steps N times. How to stop. 4. A method for resting a suspended load according to claim 4, wherein the predetermined acceleration/deceleration force is a maximum acceleration/deceleration force possessed by the moving body. 5. In claim 3, the reference equivalent rope length la for which the time Ta corresponds to one period of swing of the simple pendulum
, and when the actual equivalent rope length l is longer than the la, the number of times N is set to 1. 6. In claim 3, the reference equivalent rope length la for which the time Ta corresponds to one period of swing of the simple pendulum
, and the actual equivalent rope length l is la/4<l<
A method for resting a suspended load, characterized in that the number of times N is set to 2 when the relationship is la. 7. In claim 3, the reference equivalent rope length la for which the time Ta corresponds to one period of swing of the simple pendulum
, and the actual equivalent rope length l is la/9<l<
A method for resting a suspended load, characterized in that the number of times N is 3 when the relationship is la/4. 8. When a predetermined acceleration/deceleration force is applied to a moving body with a suspended load via a rope, find the time Ta until the moving body reaches the target speed, and calculate that the time Ta corresponds to one period of swing of the simple pendulum. Find the matching standard equivalent rope length la, and calculate that the actual equivalent rope length l is the standard equivalent rope length la.
If the time T is longer than the time Ta, the time T
1, the predetermined acceleration/deceleration force is applied to the movable body to move the movable body, and then the time T2 is half the difference between the swing period T due to the actual equivalent rope length l and the time Ta.
the acceleration/deceleration force applied to the movable body is set to zero during the time T1, and then the predetermined acceleration/deceleration force is applied to the movable body to move the movable body during the time T1. Steady rest method. 9. A method for resting a suspended load according to claim 8, wherein the predetermined acceleration/deceleration force is a maximum acceleration/deceleration force possessed by the moving body. 10. When a predetermined acceleration/deceleration force is applied to a moving body with a suspended load via a rope, find the time Ta until the moving body reaches the target speed, and the time Ta corresponds to one cycle of swing of the simple pendulum. Find the standard equivalent rope length la, and the actual equivalent rope length l is the standard equivalent rope length la.
is shorter than la/4 and longer than la/4, the predetermined acceleration/deceleration force is applied to the movable body for a time T1, which is 1/4 of the time Ta, and the movable body is moved; The acceleration/deceleration force applied to the moving body is set to zero during a time T2 which is 1/4 of the difference between the time Ta and twice the end-of-swing period T due to the equivalent rope length l, and then, during the time T1, Applying the predetermined acceleration/deceleration force to the movable body for twice the time to move the movable body, Next, for the time T2, move the movable body in equal succession, Next, for the time T2 A method for resting a suspended load, comprising: applying the predetermined acceleration/deceleration force to the movable body during T1 to move the movable body. 11. A method for resting a suspended load according to claim 10, wherein the predetermined acceleration/deceleration force is a maximum acceleration/deceleration force possessed by the moving body. 12. The load is suspended via a rope, and when accelerating or decelerating the movement of the trolley running on the girder and the moving body with the load suspended via the rope, the moving body reaches the target speed. The maximum acceleration/deceleration force is applied to the moving body until the maximum acceleration/deceleration force is applied to the moving body, and the acceleration/deceleration force applied to the moving body is zero in the middle of each period of swing of the hanging load during acceleration/deceleration, and the total time for applying the maximum acceleration/deceleration force is The time Ta required for the moving body to reach the target speed when the maximum acceleration/deceleration force is applied to the moving body is the same, and the length of the period during which the acceleration/deceleration force is zero is determined by the maximum acceleration/deceleration force and the adjustment to zero. A control device that sets the size of the suspended load so that it can be positioned below the vertical line of the moving body at the end of each period of swing of the suspended load when accelerated or decelerated at speed; Device.