JPS5859189A - Method of laterally moving load hung - 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 The present invention relates to a method for moving a suspended load laterally, according to which the speed of moving a load-bearing trolley laterally is determined by two phases of change in speed, The pendulum or oscillating motion can be suppressed by dividing the phase into an intermediate phase with a constant velocity. The change in speed that occurs at the same time as the load is raised or lowered causes a swing in the load, which is substantially eliminated when the speed change ends.

It has long been known to control the raising and lowering of loads by first raising the load to a level suitable for lateral movement and then controlling the lateral movement of the load so that the residual swing is minimized. However, this is relatively time consuming, and it is desirable to be able to raise or lower the load while simultaneously controlling the load to minimize residual pendulum motion.

One method of obtaining an acceleration that inhibits pendulum motion at a constant rope length is disclosed in German Patent No. 1,172,413. In this patent, the suspension point of the load rope is accelerated with a constant acceleration to half the desired final velocity. This acceleration causes the suspended load to undergo an oscillatory or rocking motion. The trolley continues to move at half the constant maximum speed until the load swing angle is the same as when the acceleration was interrupted, then acceleration begins again increasing the trolley speed to its final value, and the load Eliminate the pendulum motion of . The two acceleration phases are of the same length. That method has very limited use. This is because, on the one hand, it serves to suppress the pendulum movement only when the length of the rope is constant, and on the other hand, it is necessary to directly measure the angle of the rope.

The present invention is a fast and effective load swing suppression method for changing the speed of a trolley, which method does not require direct measurement of the load swing angle, and also allows changes in trolley speed. is effective when it occurs simultaneously with a change in the length of the rocking motion. 71 The invention allows the length of the rope between the load and the trolley to be changed during lateral movement, and two acceleration phases are used, which are made different lengths in time when necessary, and A constant value is given to the acceleration value of the intermediate phase, which is zero. Tore provides a solution to the above problem.

As an example of the change in speed according to the invention, the specific case of acceleration from rest will now be described. Acceleration in this manner comprises one acceleration phase with a constant maximum acceleration followed by one phase with a constant trolley speed, after which a new acceleration phase with a maximum acceleration brings the trolley speed up to the final speed. will be increased. The lengths of the two acceleration phases are generally not the same. The different times of the two acceleration phases are estimated by running the accelerations in a simulator, where the second acceleration begins a certain amount of time after the first acceleration has ended. The time for the reversal of the pendulum motion of the load thus occurring is then measured, and then 1. It is calculated from the calculation diagram that the second acceleration is started again in order to minimize the remaining pendulum movement. This provides fast load motion that minimizes pendulum motion of the rest. It is an effective method of accelerating the grab, thus reducing start-up time, which reduces cycle time during unloading.

The invention will be explained in more detail with reference to the accompanying drawings, in which: FIG.

FIG. 1a shows the variation of the swing angle (θ) of the load as a function of time (1,) during the lateral movement of the load, ie during the movement of the trolley supporting the grab. FIG. 1b shows two acceleration phases (A) and (C') and an intermediate phase with zero acceleration (B). Figure 1c shows the phase (A), (
The velocity (V) of the trolley in B) and (C) is shown. In order to suppress the swinging motion of the load, phase (C)
It is very important to determine the correct start time.

The known final velocity (Vm) and known acceleration (a) give: Time A + C-Vm/a. The difference between (A) and (C) required to best suppress rocking motion is due to the change in rope length during acceleration. The microcomputer controlling the crane has in its memory a preprogrammed table of difference values C-A=W. Figure 3 shows
Give the value of (W) when the length of the rope decreases during acceleration. The lengths of the two acceleration periods are now obtained as . If, for example, the lifting from 25 meters to 10 meters occurs simultaneously with the horizontal acceleration, Figure 3 shows that W = 0.4 s, which if vm == 4 m/S. = 1 m/S2
Then, C=2.28 and A=1.8 s are given. Now, the question is when this 2.2 second acceleration phase starts.

The answer is given by a moving simulator.

The oscillating motion of the load is 1 m/m for 1.8 seconds in our example.
It is simulated with an acceleration of S2. Then a=0 and the change in load is therefore rapidly reversed. (See curve 4 in Fig. 2, where the load swing angle (θ) is given as a function of the simulation time (1).) The acceleration of the trolley is then started again, e.g. The acceleration is the rocking motion dθ(
5) a (5) f That is, dt is maintained until the direction is changed with □=0. Now this time (5) is determined to be equal to t3, which in our example is 1, = time (5) -2,2s : giving the time at which the second acceleration begins. Thus, t:L+t2, and t3 are known. Curve 6 in Figure 2 shows the simulation;
These varying times of trolley acceleration were used there. At the end of acceleration (t3) both the swing angle of the load and its angular velocity are almost zero.

The above simulation can be done in advance,
Multiple simulations can then be stored in a control program library. It can also be done in real time, for example when the acceleration phase (A) is actually in progress. For the simulation of the load swing angle, the following linearized iterative formula is used, for example:

θ(t+h)=θ(t) 10hh(10h)j(t,+h
)=z(t,)+h; (t) where h is the time stage, θ, θ, and θ are the swing angle, angular velocity, and angular acceleration of the load, and l is the moment of the swing motion. is the length of the oscillating motion, a is the acceleration of the trolley, and g is the acceleration due to gravity.

If the load were to be decelerated and lowered instead of being accelerated and raised, the calculations for changes in deceleration would be made similarly. The time j-order A-B-C of FIG. 1 is now reversed.

In the above method it is also possible to simultaneously accelerate and lower the load or simultaneously decelerate and raise it. In that case, a calculation chart similar to that shown in FIG. 3 must be used.

The values according to the calculation chart in Figure 6 are a = 1m/82,
dl t (-;) -2m/S % and W= (t3
t2) t:r (see the inset time curve in FIG. 3).

Line 7 of FIG. 3 shows the values at lo and IC, ie, without lifting or lowering of the item during the movement of the load, and therefore outside the scope of the invention.

Other types of charts can be used instead of calculation charts and, of course, the calculation of (W) can also be performed with the aid of a computer.

The present invention can be modified in many ways within the scope of the appended claims. Of course, it is possible to perform acceleration at a value lower than the maximum value.

[Brief explanation of the drawing]

Figures 1a, 1b, and 1C show the relationship between the swing angle, trolley acceleration, and trolley speed with respect to time, and Figure 2 shows the relationship between the swing angle and the time when the simulator is moving. The relationship is shown and FIG. 3 shows a calculation chart for determining the different acceleration phases mentioned above. Symbols A and C in the drawings indicate "acceleration phase J," B indicates "intermediate phase," and ■ indicates "
``Trolley speed'', w is ``acceleration time J, a is ``acceleration'',
t indicates "time" and θ indicates "swing angle". Representatives: Asamura and 4 people

Claims (1)

[Scope of Claims] (1) A method of moving a suspended load laterally, the speed at which a trolley supporting said load moves laterally is divided into two phases and an intermediate phase having an essentially constant speed. the length of the rope between the load and the trolley can be varied during the lateral movement, and the the two acceleration phases are generally of different lengths in time,
A constant value is given to the acceleration value zero of the intermediate phase,
A method of moving a suspended load laterally. (2. The method according to claim 1, wherein the acceleration in the two acceleration phases is given a constant value with respect to the acceleration value of zero in the intermediate phase. (3) A method according to claim 1 or #2, in which the difference in length between the two acceleration phases is calculated using a previously drawn calculation chart or, for example, the first and last A method for laterally moving a suspended load, characterized in that the length of the rope is determined from a table using as a variable. (4) A method according to claim 1 or 2, characterized in that The lengths of the two acceleration phases are determined by mathematically repeating the rocking motion of the load, thereby moving the model with different values of the difference between the two acceleration times (W), and the ( (5) A method for laterally moving a suspended load, characterized in that W) is selected to give a rocking motion of a minimum load residual υ at the end of acceleration. (5) Claim 1 4. The method according to any one of paragraphs 1 through 4, wherein the time at which the second acceleration phase begins is determined by repeating a mathematical model of the oscillating load. How to move the loaded load laterally.