DE2930564A1 - BRIDGE CRANE CONTROL - Google Patents

Description

Patent attorneys 8000 Munich 22 Steinsdorfstrasse 21-22 Telephone 089/22 94 41

Heemaf BV
Bornsestraat 5, Hengelo, the Netherlands

B back crane control

0 3CG: / 0593

B back crane control

The invention relates to a method and a device for controlling the movement of the cat and the length of the takeaway of an overhead crane.

Systems are known in which the deflection angle of the Takeis measured and on the basis of this the movement of the cat is varied in such a way that the deflection angle at the end position of the takeis 0 or almost ü.

It is also possible, based on experience, in dependence movement patterns determined by the distance to be covered and execute them automatically.

The older disadvantage of the first mentioned control method is that it is difficult to measure the deflection angle while also the tax system is complicated. The second method mentioned has the disadvantage that the course of the movement is not optimalized because a wah] out of a number existing patterns must be made.

It is the object of the invention to provide a control method create a load with the help of an overhead crane in the shortest possible time and with the smallest possible residual deflection of the takeaway can be brought to the desired destination.

According to the invention, this is achieved on the basis of FIG the starting position and the desired end position of the trolley and the takeaway, the maximum permissible during transport Rigging lengths, repeated for different acceleration values urt.or use of the law of momentum:

0300U / 0593

ρ 2330564

- S-

2
A ² CP 2 dv dl? he _fO cos.ft ⁷ . d χ

4t ² y dt at yy

where 6P = deflection angle with respect to the vertical, y = length of the take, g = acceleration of gravity and χ «i, age of the cat, the residual deflection of the takei at the end position the results are calculated by comparing this acceleration at which the residual deflection is minimal, determined and the measured acceleration value dem Control mechanism of the overhead crane is fed.

In the proposed method, the desired movement pattern can be optimized before the overhead crane is controlled, assuming that the calculations can be carried out quickly, so that the waiting time is negligible. The control system according to the invention is an open, ie not fed back, control. Before the calculation, a number of acceleration values can be excluded due to the maximum permissible rigging lengths during transport and the distance to be covered by the trolley. This has the advantage that only a limited number of calculations need to be carried out, because this acceleration results that are not considered and that are excluded priori. This can be achieved by dividing the acceleration values to be used into two groups, one of which is used for the maximum permissible rigging lengths and the distance to be covered by the trolley below and one for the maximum permissible rigging lengths and the distance to be covered by the trolley above selected values.

It will be clear that in order to be able to perform a large number of calculations in the shortest possible time,

03 0014/0593

g _aln . y ₌ y _t

preferably electronic means are used. For this purpose, according to the invention, a device for performing is provided proposed the above method, characterized by an analog simulation circuit for Simulating the differential equation:

dt y dt dt γ γ dt

a generator circuit for generating and supplying different pulse signals to the simulation circuit, a comparison circuit connected to the output of the simulation circuit for comparing their output signals with previous output signals and determining the output signals with the lowest possible \ γ (t), a with the Ve rg Ie ic hung circuit device and the generator circuit connected memory for storing the pulse signal associated with the γ (t) and a circuit connected to the memory for generating control signals for the bridge crane. It is also proposed to use an exclusion circuit connected to the simulation circuit and the generator circuit, with which, during transport, due to the maximum permissible cable lengths, undesired pulse signals formed by the generator circuit can be excluded. Because the signals obtained are analog signals, the control signals are fed to the overhead crane via an integrator circuit.

The invention is explained below with reference to a block diagram according to the accompanying drawing.

In the block diagram, χ is the starting position of _{the trolley, y Q is} the starting length of the takei, y, the desired end length of the takei, x. the end position of the trolley, y the initial speed of the movement of the takei, K,, K ,,

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K denotes the limit values of the range from which the rig should stay, a (t) the acceleration value, y (t) the current rig length and (O (t) the deflection angle with respect to the vertical.

The initial conditions are introduced into memory 2. This concerns the data χ, y, y ,, χ ,, y, K,, K ,, K. A start command S 1 is then given, which makes the control circuit 1 effective. As a result, the aforementioned initial conditions can be recorded in memory 2. On the basis of the initial data, the selection circuit 10 decides whether the so-called short or long program should be executed. This choice is determined on the basis of the distance to be covered by the trolley and the expected course of the length of the ice. If the short program is selected, only those acceleration values are generated that fit in a short transport.
The result of the selection is communicated to the control circuit 1 by the circuit 10 by means of a signal S _2. By means of the signal S ₃ , the control circuit 1 controls the generator 3, which successively forms a number of acceleration values a (t). It is noted that only meaningful values for a (t) are generated. Acceleration values that the drive cannot achieve are not generated. Each acceleration signal is fed to the circuit 4, which has also received the signals K, K 1, and K from the circuit 2. On the basis of this data, the circuit 4 generates the signals y (t) and y (t), which represent the lifting speed of the take as a function of time. The signals mentioned are fed to the simulation circuit 5, which is an electronic model of the take and in which, in a known manner, by means of operational amplifiers, selection of resistors, self-inductors and capacitors, the differential equation

030014/0593

iNSPECTECT

^ _? I cos.? dfx!

^dt Υ dt dt y ° ⁷ y ' _dt 2 -

is simulated. As a result, the circuit 5 gives the deflection angle ^ (t) and the angular velocity ^ P (t). The latter signals are used by the judging circuit 6 supplied. This judging circuit 6 compares the supplied values with the previously generated values, selects the most desired value up to now and maintains this Signals to memory 7. It is noted that the most desirable value is that at which the calculated Residual value of the deflection is minimal. The associated value of the acceleration is stored in the memory by the generator 3 7 established. After the optimum value has been achieved in this way, the signal S. Drive generator circuit 8 made effective, the optimum Receives value from the memory 7 and outputs the generated control signal to the integrator 9. The drive of the The overhead crane is controlled by the integrator 9.

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ORIGINAL INSPECTED

Claims (6)

PATENT CLAIMS 1. A method for controlling the movement of the trolley and the length of the take-up of an overhead crane, characterized in that that based on the starting position and the desired end position of the trolley and the takeaway during the Transportes maximum permissible rigging lengths, repeated for different acceleration values using the Impul smome η tge se t ze s: dt ² ■ y dt dt where ^ P = angle of deflection in relation to the vertical »y = length of the takei, g = acceleration of gravity and x = position of the trolley, the remaining deflection of the throwing at the end position is calculated, the results are calculated by comparing this acceleration at which the remaining deflection is minimal is determined and the measured acceleration value is fed to the control mechanism of the overhead crane. 2. The method according to claim 1, characterized in that the acceleration values due to the during the Transportes maximum rigging lengths and the through the Cat can be selected to travel distance. 3. The method according to claim 2, characterized in that the acceleration values to be applied are divided into two groups of which one with the highest permissible rig lengths and the distance to be covered by the trolley below 030014/0593 and one at the highest permissible rigging lengths and the one by the Cat distance above the chosen fourth is used. 4. Apparatus for performing the method according to claims 1-3 / characterized by an analog simulation circuit to simulate the differential equation: _s . _{n + β m sn} y ät ^Z y dt dt y 'ν dt ² ' a generator circuit for generating and supplying the simulation circuit with different pulse signals, a comparison circuit connected to the output of the simulation circuit for comparing their output signals and determining the output signals with the lowest possible ^ (t), a memory connected to the comparison circuit and the generator circuit for storing the pulse signal associated with ψί t) and a circuit connected to the memory for generating control signals for the overhead crane. 5. Device "according to claim 4, characterized by a with the simulation circuit and the generator circuit associated exclusion circuit with which, during the Transportes, due to the maximum cable lengths, undesired impulse signals formed by the generator set can be excluded. 6. Apparatus according to claim 4-6, characterized in that that the control signals via an integrator circuit to the Bridge crane is fed. 03CJ'A / 0593