EP3313770B1 - Crane and method for controlling same - Google Patents

Description

The present invention relates to a crane, in particular in the form of a container stacking or gantry crane, with electric actuators for lifting and / or moving loads and / or crane elements, a generator for supplying power to the actuators, an internal combustion engine for driving the generator, input means for inputting of control commands for the actuators and a control device for controlling the actuators as a function of the control commands entered. The invention also relates to a method for controlling such a crane.

The term "crane" is to be understood broadly in the context of the present application and can in particular container stacking cranes, port gantry cranes, so-called RTG cranes, that is rubber-tired gantry cranes for containers, but also construction cranes in the form of, for example, tower cranes, telescopic cranes or derrick cranes include.

In such electric cranes, i.e. cranes with electric drives that are supplied by a generator that is operated by an internal combustion engine, an above-average fuel consumption usually occurs in idle or partial load operation, since the generator unit usually operates at a fixed frequency of, for example 50 / 60 Hertz is operated.

In order to reduce consumption, especially when idling, there are already approaches in which the speed of the internal combustion engine is reduced when all electrical drives are switched off. In particular when using a frequency converter to control the electrical drives, there is no longer any need to provide a voltage supply with a fixed frequency, for example in the form of the aforementioned 50/60 Hertz supply. Since the mains frequency applied to the actuators can be varied with respect to the generator speed using the frequency converter, it is possible to operate the internal combustion engine that drives the generator at a freely selectable frequency. In particular, this allows the speed of the internal combustion engine to be selected such that the internal combustion engine is operated in its optimum consumption, that is, in an operating range with the lowest possible losses and / or the lowest possible consumption.

When the speed of the internal combustion engine is lowered in this way and / or when an operating point of the internal combustion engine that is optimal in terms of consumption is set, however, the crane performance can be reduced, for example, in that only reduced adjusting speeds can be achieved or limited loads can be lifted. In the worst case, the combustion engine can stall and the crane first has to be restarted before the lifting or actuating task can be carried out.

It has therefore already been proposed that the electric actuators should no longer be fed with electrical energy directly from the generator, but that a battery or accumulator should be inserted into which the generator generated electrical energy is stored and from which the electrical actuators can then be supplied, cf. US 2012/0089287 A1 . The load on the internal combustion engine can be evened out and power peaks of the electric actuators can be absorbed via the buffer effect of the accumulator. The interconnection of such an accumulator and its regulation with regard to feeding in and feeding out electrical power, however, requires additional electrical regulator components. In addition, the batteries themselves are not only heavy and expensive, but also have a limited service life.

The present invention is therefore based on the object of specifying an improved crane and an improved method for controlling such a crane, which avoid the disadvantages of the prior art and further develop the latter in an advantageous manner. In particular, the fuel requirement of a crane equipped with electric actuators should be reduced as much as possible without noticeably impairing crane performance.

According to the invention, the stated object is achieved by a crane according to claim 1 and a method according to claim 10. Preferred embodiments of the invention are the subject matter of the dependent claims.

Provision is therefore made for the internal combustion engine to be reduced in speed and / or torque when the electric actuators are idling or at partial load, but to increase the speed and / or torque of the internal combustion engine again in good time before the actuators achieve a higher output or even full output need. In order not to suffer restrictions in crane operation or even stall the combustion engine, the operation of the combustion engine is not tracked after the actual actual power requirement of the actuators, but adjusted in advance in order to meet future power requirements of the electric actuators. According to the invention, the control device has a determination device for determining and / or estimating a future power requirement of the electric actuators on the basis of the actuation of the input means with which control commands for the actuators are entered and the current operating state of the actuators, and an engine control unit for controlling the internal combustion engine as a function of the estimated / determined future power requirement. Because the control device anticipates the power requirement of the actuators before the actuators actually reach the operating point at which this power requirement occurs, the internal combustion engine can be driven to an operating point that is optimal or at least suitable for this power requirement in good time. In particular, the speed and / or the torque of the internal combustion engine can be increased in order to meet a subsequent increasing power requirement of the electric actuators.

With such a leading control of the internal combustion engine, the actuating drives are advantageously supplied directly and completely by the generator with current or electrical energy, so that no intermediate storage of the electrical energy generated is necessary. Corresponding electrical energy stores such as batteries, accumulators and the like and also corresponding controller modules for feeding the energy into and out of such intermediate stores are dispensed with. The electric actuators with their energy supply connections only need to be connected directly to the generator and can be supplied exclusively and completely by the energy that the generator is currently making available. The actuators are supplied online, so to speak, directly from the generator. By saving batteries, rechargeable batteries and associated control components for storing and withdrawing energy, the system can be designed simply and inexpensively.

In a further development of the invention, the control device can adjust the internal combustion engine faster or slower and / or, if necessary, also delay the implementation of the control commands to the actuators or move the actuators to a desired operating point with a delay in order to be driven by the internal combustion engine or the one driven by it Generator to always provide the required power for the actuators in good time. When the power requirement of the actuators increases, the power output of the internal combustion engine can be reduced and / or the associated power supply of the generator can be increased faster than the power requirement of the actuators increases. Alternatively or additionally, when the power requirement of the actuators falls, the power provided by the internal combustion engine can be reduced more slowly than the power of the actuators actually falls. In other words, when the power requirement increases, the internal combustion engine can be advanced in terms of speed and / or torque and tracked when the power requirement falls.

Advantageously, the control device can include a speed control module for controlling the speed of the internal combustion engine, wherein said speed control module can be designed such that the internal combustion engine is adjusted with the smallest possible, but as large as necessary speed change in order to meet the expected power requirement of the electric actuators to just achieve the necessary or desired operating state without major excesses.

In particular, the control device can comprise an acceleration control module for controlling the acceleration of the internal combustion engine, wherein said acceleration control module can in particular be designed in such a way that the internal combustion engine is adjusted with the smallest possible but as large as necessary acceleration in order to achieve the acceleration to be expected To achieve the required or desired operating state just in time. Because the internal combustion engine is advantageously only operated with the minimum necessary acceleration in order to reach a new operating point, the mechanics of the internal combustion engine can be protected and unnecessarily increased fuel consumption due to excessive acceleration can be avoided.

Advantageously, said acceleration control module can include determining means which, based on the current operating state of the electric actuators and the actuation of the input means or the input control commands, determine the point in time at which the actuators will determine the future Will have or achieve performance requirements. On the basis of this specific point in time or a correspondingly determined period of time which is estimated for reaching the operating point of the actuators or required by the actuators, the acceleration control module can then determine the necessary acceleration of the internal combustion engine in order to ensure that the then occurring Power requirement of the actuators to achieve the necessary or desired operating range.

In particular, the control device and the engine control unit can be designed such that the future power requirement is calculated so quickly and the internal combustion engine is adjusted so quickly that the internal combustion engine reaches the operating point calculated for the future power requirement, shortly before or at the latest when the electric actuators anticipate theirs to reach the final operating point. This makes it possible for the crane to be operated without a loss of performance and still achieve fuel savings.

In a further development of the invention, said engine control device can include a speed control device for variably controlling the speed of the internal combustion engine as a function of the future power requirement and as a function of the current operating state of the actuators. As an alternative or in addition, the engine control device can also include a torque control device, by means of which, as an alternative or in addition to a speed control, the torque of the internal combustion engine can be controlled as a function of the future power requirement. However, the engine control device can also get by on its own with a speed control device and on its own generate a speed control signal with the aid of which the internal combustion engine is driven to the required operating point in advance.

The determination of the future power requirement, on the basis of which the internal combustion engine is then controlled, can basically take place in various ways or take into account various operating parameters. In advantageous In a further development of the invention, a strength and / or speed and / or direction of the actuation of the input means and / or an associated size and / or change speed of a control command brought about by the input means can be taken into account. For example, the internal combustion engine can be adjusted more quickly if the input means, for example in the form of a joystick, is actuated more quickly to control the crane actuation movements, since rapid actuation indicates a greater deflection and thus a high actuation speed requirement. Alternatively or additionally, a deflection angle or a travel of the joystick or another input means can also be taken into account, for example to the effect that a greater or further deflection is converted into a relatively quick increase in the speed and / or the torque of the internal combustion engine, since a strong joystick movement a greater increase in power requirements can be expected.

As an alternative or in addition to such consideration of the actuation speed and / or actuation acceleration and / or the actuation path of the input means, the number of actuating drives affected by the input control commands can also be taken into account for determining the future power requirement. If, for example, a control command to lift the hoist and a control command to rotate the boom or move the portal are given simultaneously or one after the other, a greater increase in the power requirement can be assumed, while a control command for only one actuator can assume a lower future power requirement . Accordingly, the engine control unit can provide a stronger and / or faster adjustment of the operating point of the internal combustion engine when inputting control commands that affect several actuators and / or provide a smaller and / or slower adjustment of the operating point of the internal combustion engine with only a few or only one actuator concerned .

As an alternative or in addition, it can also be taken into account for the determination of the power requirement which or which of the actuating drives is to be affected or adjusted as desired by an input control command. For example, it can be assumed that the power requirement increases more strongly when the hoist is actuated than when the slewing gear or the bridge drive is actuated. In this respect, the future power requirement can be determined as a function of the identity of the actuating actuator affected by the control commands.

Alternatively or in addition, the requested speed and / or the requested direction of an actuating movement can also be taken into account for determining the future power requirement. If a crane operator requests a quick lift, for example by actuating the input means accordingly, the future power requirement can be estimated to be higher than for the case in which the crane operator only requests a slow lift.

In a further development of the invention, the control device and / or engine control device also takes into account the generator speed for an optimal voltage supply to the electric actuators. In particular, the speed and / or the torque of the internal combustion engine can be adapted to the needs of the generator based on the determined future power requirement. For example, the engine control unit can take into account that the voltage that can be provided by the generator can depend on its speed. Therefore, for a predetermined power requirement, which is associated with a certain voltage level or voltage requirement, the internal combustion engine can be run to a speed that would not be necessary for the output of the internal combustion engine, but takes into account the conditions of the generator and takes this into account. For example, the internal combustion engine can be run at an increased speed, even if the internal combustion engine could provide the required power even at a lower speed in order to take into account the conditions of the generator due to the aforementioned increased speed and to operate it in a frequency range in which it can achieve the can provide the required voltage.

The control device can advantageously control the electric actuators of the crane via a frequency converter.

According to the invention, the control device takes into account the power level of the internal combustion engine when controlling the electrical actuators, so that crane movements are limited in terms of speed and / or acceleration in order to limit the electrical power requirement required for the crane movements so that the performance of the internal combustion engine is not reached or . is not exceeded. In this way, overloading of the internal combustion engine and the resulting death of the internal combustion engine can be prevented. The mentioned power protection for the internal combustion engine by restricting the power consumption of the electric actuators can be particularly useful if, for example, the internal combustion engine cannot achieve its rated output, for example as a result of a defective injection nozzle, a clogged fuel filter or the like.

The power limitation for the electric actuators is implemented by limiting the maximum lifting speed or the maximum travel speed of the respective actuator. In addition, a speed and / or acceleration ramp for regulating the respective actuator can be flattened or limited. If necessary, it can also be sufficient to execute simultaneously requested actuating movements by two or more actuating drives one after the other, so that the performance requirements of the actuating drives do not have to be added up, but occur one after the other. Other control strategies for observing the performance limits of the internal combustion engine are possible.

Fig. 1:

eine schematische Darstellung eines Krans in Form eines gummibereiften Container-Stapelkrans, wobei die Teilansichten a und b den Kran in Front- und Seitenansichten zeigen, und

Fig. 2:

eine schematische Darstellung der Steuervorrichtung des Krans, die den zukünftigen Leistungsbedarf der elektrischen Stellantriebe des Krans aus Fig. 1 im Voraus schätzt bzw. bestimmt und in Abhängigkeit des zukünftigen Leistungsbedarfs den Verbrennungsmotor des Krans aus Fig. 1, der dessen Generator zum Energie versorgen der elektrischen Antriebe antreibt, steuert.

The invention is explained in more detail below with the aid of a preferred exemplary embodiment and associated drawings. In the drawings show:

Fig. 1:

a schematic representation of a crane in the form of a rubber-tired container stacking crane, the partial views a and b show the crane in front and side views, and

Fig. 2:

a schematic representation of the control device of the crane, which determines the future power requirements of the electric actuators of the crane Fig. 1 estimates or determines the crane's internal combustion engine in advance, depending on future power requirements Fig. 1 , which drives its generator to supply energy to the electric drives.

How Fig. 1 shows, the crane 1 can be designed as a container stacking crane which has a portal 2 which can be moved by means of a rubber-tyred chassis 4 at a container loading station. A transversely movable bridge 3 can be arranged on the portal 2, on which a lifting gear 5, by means of which a container 21 can be gripped, can be raised and lowered.

To adjust the mentioned crane elements, electrical actuators are provided, in particular a lifting drive 6 for raising and lowering the mentioned lifting gear 5, which can be done for example by means of a lifting rope and corresponding cable winches, then a bridge drive 7, by means of which the bridge 3 can be moved along the portal 2 can, as well as a drive 8, by means of which the chassis 4 can be driven.

Said electrical actuators 6, 7 and 8 are fed with electrical energy from a generator 9, which is driven by an internal combustion engine 10, for example in the form of a diesel engine.

To control the crane setting movements, input means 14 are provided for a crane operator, which are arranged in a crane operator's cab 22 and, for example, a joystick 15, input keys, control levers or slide switches and the like can include. By means of the input means 14 mentioned, control commands can be generated or entered, which are used to control the mentioned actuating drives in the form of the lifting drive 6, the bridge drive 7 and the travel drive 8.

Depending on the control commands mentioned, an electrical control device 11 can then control the actuating drives mentioned, which can advantageously take place via a frequency converter which can convert the frequency generated by the generator 9 in a known manner.

The control device 11 further adapts the speed and / or the torque of the internal combustion engine 10 to the respective crane operating state in order, on the one hand, to enable crane handling without performance disadvantages and, on the other hand, to achieve the lowest possible fuel consumption.

How Fig. 2 shows, the control device 11 can include a determination device 12 for this purpose, by means of which, based on the current operating state of the actuators 6, 7 and 8 and the actuation of the input means 14, the future power requirement of the actuators and thus the power required by the internal combustion engine 10 and the generator 9 is calculated or is determined or estimated. For this purpose, various sensor signals and / or information that can characterize the actuation of the input means, the crane operating state and structural characteristics of the crane are fed to the named determination device 12. In particular, the determination device 12, such as this Fig. 2 shows information on the actuation of the joystick 15, information on the actuation speed, information on the ACTUAL power of the actuators and / or the internal combustion engine and / or the generator, information on further operating parameters such as internal combustion engine speed, internal combustion engine torque, travel or adjustment speed of the Actuators or other crane elements and / or information about the ACTUAL load on the crane elements and / or other information are supplied.

The named determination device 12 of the control device 11 calculates from this in the manner described above the future power requirement that occurs when the electric actuators 6, 7 and 8 reach the operating point requested by the input control commands.

From the determined future power requirement, the engine control device 13 of the control device 11 then calculates the operating point or operating range required for this, in particular the speed and / or torque, of the internal combustion engine 10.

The engine control unit 13 takes into account how Fig. 2 shows also the conditions and requirements of the generator 9, in particular which speed the generator actually needs in order to be able to provide the voltage and amount of current required for future power requirements. Here, generator characteristics, for example voltage output over speed, and the like can find input. In addition, framework conditions such as a fixed reference voltage that is required can be taken into account.

The engine control unit 13 then sets the actual operating point for the internal combustion engine 10 as a result of this calculation process, the engine control unit 13 also being able to calculate the acceleration with which the internal combustion engine 10 is driven to the new operating point. The engine control device 13 and / or the control device 11 can for this purpose have an acceleration control module 16 which, by means of time determination means 17, calculates the point in time or the period of time at which or in which the electric actuators 6, 7 and 8 reach the anticipated operating point at which the future power demand actually occurs. Acceleration determination means 18 then calculate the necessary acceleration for internal combustion engine 10 from this.

How Fig. 2 shows, the engine control unit 13 and / or the control device 11 can only get by with one control speed command for the engine. It takes a control signal for the torque cannot also be generated, even if this would be possible in principle.

A speed controller 19 and / or a torque controller 20 of the engine control device 13 then drive the internal combustion engine 10 to the desired operating point.

Claims (10)

1. Crane, in particular a container stacking or gantry crane, comprising electric actuators (6, 7, 8) for lifting and/or traveling loads and/or crane elements, a generator (9) for supplying the electric actuators (6, 7, 8) with energy, an internal combustion engine (10) for driving the generator (9), input means (14) for entering control commands for the actuators (6, 7, 8) and a control device (11) for controlling the actuators in dependence on the control commands entered, wherein the control device (11) includes a determination device (12) for determining and/or estimating a future power demand of the actuators (6, 7, 8) on the basis of the actuation of the input means (14) and the current operating condition of the actuators (6, 7, 8), and an engine control unit (13) with a speed control device (19) for variably controlling the rotary spssed of the internal combustion engine (10) in dependence on the estimated/determined future power demand and the current operating condition of the actuators (6, 7, 8), characterited in that the electric actuators (6, 7, 8) can directly and completely be supplied with the electric energy currently provided each by the at least one generator (9) and no intermediate storage of the electric energy generated by the generator (9) is provided, wherein the control device (11) is provided to limit the velocity and/or acceleration of the actuators (6, 7, 8) by considering the performance limit of the internal combustion engine (10) and to adjust the internal combustion engine (10) with regard to the speed to an operating point in which the internal combustion engine (10) provides the calculated/estimated power demand substantially without an excess of power, before the actuators (6, 7, 8) reach the operating point requested by the control commands of the input means (14) and the corresponding power demand.
2. Crane according to the preceding claim, wherein the control device includes an acceleration control module (16) for controlling the acceleration of the internal combustion engine (10) and/or the actuators (6, 7, 8) such that with increasing future power demand the internal combustion engine (10) is brought into its operating condition determined for this future power demand, before the actuators (6, 7, 8) actually reach this future power demand.
3. Crane according to the preceding claim, wherein the acceleration control module (16) is configured such that the internal combustion engine (10) is adjusted with a minimally necessary and/or the smallest possible acceleration with which the operating condition of the internal combustion engine (10) required for the determined future power demand is just reached in time.
4. Crane according to any of the two preceding claims, wherein the acceleration control module (16) includes a determination means (17) for determining a point in time and/or a time period in which the actuators (6, 7, 8) reach the future power demand, and acceleration determination means (18) for determining the acceleration of the internal combustion engine (10) in dependence on the determined point in time or the determined time period.
5. Crane according to any the preceding claims, wherein the speed control device (19) is formed to adjust a minimally necessary and/or the smallest possible change in speed with which the future power demand is reached.
6. Crane according to any of the preceding claims, wherein the engine control unit (13) includes a torque control device (20) for variably controlling the torque of the internal combustion engine (10) in dependence on the future power demand and the current operating condition of the actuators (6, 7, 8).
7. Crane according to any of the preceding claims, wherein the control device (11) actuates the actuators (6, 7, 8) via a frequency converter.
8. Crane according to any of the preceding claims, wherein the determination device (12) is configured to determine the future power demand of the electric actuators based upon

   - a strength and/or velocity and/or a direction of the actuation of the input means (14), and/or

   - the number of actuators (6, 7, 8) concerned with an entered control command, and/or

   - the identity of the actuator (6, 7, 8) concerned with a control command, and/or

   - the velocity requested by the entered control commands and/or the requested direction of the actuating movement of the actuator concerned with the control commands.
9. Crane according to any of the preceding claims, wherein the engine control unit (13) is configured to determine the speed of the internal combustion engine (10) in dependence on the speed-voltage curve of the generator (9).
10. A method for controlling a crane (1) with electric actuators (6, 7, 8) for lifting and/or traveling loads and/or crane elements, a generator (9) for supplying the electric actuators (6, 7, 8) with energy, an internal combustion engine (10) for driving the generator (9), input means (14) for entering control commands for the actuators (6, 7, 8) and a control device (11) for controlling the actuators in dependence on the control commands entered, wherein the method comprises the following steps:

    - detecting an actuation of the input means (14) and/or the control commands generated by the actuation of the input means (14),

    - calculating and/or estimating and/or determining a future power demand of the actuators (6, 7, 8) by the control device (11) with reference to the detected actuation of the input means (14) and/or with reference to the detected control commands generated by the actuation of the input means (14), and

    - adjusting the internal combustion engine (10) with regard to the speed and/or torque to an operating point in which the internal combustion engine (10) provides the calculated/estimated power demand substantially without an excess of power, before the actuators (6, 7, 8) reach the operating point requested by the control commands of the input means (14) and the corresponding power demand,

    wherein the electric actuators (6, 7, 8) are directly and completely supplied with electric energy by the generator (9) and no intermediate storage of the electric energy generated by the generator (9) is provided, wherein the velocity and/or acceleration of the actuators (6, 7, 8) is limited by considering the performance limit of the internal combustion engine (10).

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