EP3533933B1 - Method for power management in pile foundation comprising a holder machine and an implement mounted on same - Google Patents

Description

The invention relates to a method for power management during pile foundation with a carrier machine for digging a borehole and an attachment mounted on the carrier machine for simultaneously inserting a casing into the ground, the energy supply for the attachment being provided at least partially by the carrier machine.

When grab drilling with an attachment in the form of a casing machine/pipe lathe, two independent devices work together to create a pile. The carrier machine, in the form of a dragline, includes a grab for digging a hole. A casing machine/pipe lathe also attached to the cable excavator is used to clamp the casing, which is to be inserted into the ground synchronously with the excavation by means of uniform rotational movements. The energy required for the casing oscillator is usually provided by the carrier machine. Generic methods are prior art and can, for example, the EP 3 081 737 A2 be removed.

The operator of the cable excavator/drilling device or the casing-making machine/pipe-turning machine adjusts the energy flow to the casing-making machine/pipe-turning machine, for example via a regulator. The disadvantage of this method is that the energy flow is quasi-static and can only be changed sporadically.

Depending on the work step or work cycle, it can happen that the casing machine is provided with either too much or too little energy for the respective activity, which not only increases the overall energy consumption unnecessarily, but also delays in the work process have to be accepted .

A solution is therefore being sought which knows how to overcome the disadvantages explained above.

This object is achieved by a method according to the features of claim 1. Based on the generic method, it is proposed according to the invention that a control of the carrier machine distributes the energy flow between the carrier machine and the attachment for the hydraulic, pneumatic or electrical energy supply of the attachment, with a dynamic The energy flow is regulated taking into account the current power requirements of the carrier machine and/or the attachment in order to optimize the utilization and effectiveness of the carrier machine and the attachment. The carrier machine can be, for example, a cable excavator that is equipped with a corresponding gripper drill for digging a borehole or a drill such as a Kelly drill. The attachment is, for example, a casing machine or a pipe turning machine for inserting a casing into the ground.

According to the invention, the control of the carrier machine is intended to dynamically regulate the distribution of energy between the attachment and the carrier machine, in order thereby to optimize the utilization and effectiveness of the two machines. The main concern here is hydraulic or pneumatic energy, which is made available to the attachment by the carrier machine. However, the method is not limited to a specific type of energy and could also be used for the energy management of electrical energy.

It makes sense for the controller to know the process flow or has this knowledge about future work steps of the carrier machine or the attachment. In the case of cyclic processes, this knowledge can also be learned from past cycles. If, for example, one of the two consumers always reaches its energy limits in the same partial cycle and the other consumer does not need all the energy at the same time, a dynamic adaptation can be learned. On the basis of this information about subsequent work steps, a dynamic control of the energy flow can take place. In concrete terms, the total energy required to create the pile consists of the power requirement of the carrier machine for digging the borehole and the power requirement of the attachment for inserting the casing. The respective cyclic work steps carried out on the devices are characterized by a variable power requirement. As a result, it makes sense to supply the attachment with less energy when performing less energy-intensive work steps so that the excess energy can be used in the carrier machine instead. If, instead, a process with a high power requirement takes place in the attachment and the carrier machine requires comparatively little power, it makes sense to maximize the energy flow to the attachment. As a result, individual work steps can be carried out faster in a targeted manner, which can optimize the entire process duration. This also makes it possible to optimize the entire power requirement during the piling process, because the unnecessary provision of excess energy on the carrier machine or on the attachment is prevented or at least reduced.

For dynamic control, it is conceivable to limit the flow of energy to the attachment or, under certain circumstances, to stop it completely. A limitation can, for example, take place in stages. However, stepless limitation is also conceivable in order to enable the most precise possible adjustment of the energy flow.

As claimed, the energy flow is controlled by a controller of the carrier machine. However, it is also conceivable to at least partially outsource the execution of the method to an external controller, for example to the controller of the attachment. It makes sense to exist between the carrier machine and a communication interface with the attachment in order to be able to exchange process-relevant information for the dynamic control of the energy flow between the machines.

It is also possible to exchange a request for power reduction or power increase between the machines via the communication interface. It is conceivable, for example, that the carrier machine or the controller of the carrier machine requests the attachment via the communication interface to reduce its energy consumption in order to thereby ensure a higher proportion of power for the carrier machine. Conversely, the attachment could also request an increase in the flow of energy to the attachment from the carrier machine via the communication interface.

A corresponding requirement to reduce the power of the attachment can also contain an instruction and specification of work steps to be carried out on the attachment. In this context, it is conceivable that the carrier machine specifies work steps to be carried out for the attachment or recommends one or more work steps. Such a recommendation is sensibly based on the power requirements of the base machine. If this requires a comparatively large amount of power, the specification or recommendation contains energy-saving work steps. Conversely, the execution of energy-hungry work steps is recommended/specified if excess energy is currently available from the carrier machine.

By means of the dynamic control of the energy flow, the process duration can be specifically influenced or controlled for individual work steps. This affects both work steps of the attachment and the carrier machine. Specifically, by providing additional energy, for example, the rotational movement of the attachment can be accelerated. Conversely, a reduction in performance leads to a delay or slowing down of the respective work steps.

For the pile foundation and in particular for an optimal energy consumption during the pile foundation, it is of particular importance that the casing process is synchronized with the simultaneous excavation of the borehole. For example, if the excavation of the casing is premature, there is a risk of the casing falling, causing material damage and costs. However, if the piping runs too far, the skin friction on the inside becomes too great, which can lead to higher energy costs. Accordingly, the progress of both processes should be kept approximately the same or the casing depth should slightly advance the excavation depth at a constant distance.

This relationship makes it useful to monitor the difference between the depth of the excavation and the depth of the casing, with the determined difference being taken into account in the further step in the dynamic control of the energy flow. In particular, by actively influencing the power distribution, the depth difference is kept above and/or below a lower or upper limit value.

It is particularly advantageous if the energy flow to the attachment is throttled if the casing depth is greater than the excavation depth by at least a certain limit. Conversely, it can make sense to increase or even maximize the energy flow to the attachment if the excavation depth is greater than the current casing depth by at least a certain amount. Such a connection between the difference in depth and the power distribution can be mapped in a particularly advantageous manner by a cost function, which, for example, defines the average power component to be delivered to the attachment as a function of the difference in depth.

As already indicated above, the work processes of the attachment and/or the carrier machine can be divided into cyclically occurring individual steps, which also differ from one another with regard to the power requirement. In order to optimize the power management, it is particularly advantageous to take into account the execution or future execution of the individual steps during a complete work cycle in the dynamic regulation of the energy flow. It makes sense here that the energy flow to the carrier machine is adjusted dynamically on the basis of the average power share, also taking into account the cyclic digging process of the carrier machine. This can preferably be done by multiplying the mean power value by a weighting parameter that characterizes the current single step of a complete work cycle. Concretely, it is possible that such a weighting parameter is smaller during digging and raising of the digging tool of the carrier machine than during lowering and dumping of the digging tool. Choosing the right weighting now ensures that the attachment is provided with a lower proportion of power (e.g. weighting factor less than 1) while the carrier machine is digging and lifting, since the digging and lifting process of the carrier machine is comparatively energy-intensive. Conversely, the power requirement during the lowering and emptying of the digging tool of the carrier machine is significantly lower; excess energy can be made available to the attachment by selecting a higher weighting factor, for example around 1.

Due to the geometry of the construction of a typical casing oscillator, there is an optimum efficiency of the power transmission at a certain position of the two oscillating cylinders. With large deviations in both directions, the efficiency decreases. Especially with very large casing depths, the effective oscillation angle at the front of the casing is reduced due to twisting of the casing. Against this background, it makes sense to also dynamically set this oscillation angle during operation or as the casing depths progress. In this context, it proves to be useful if the attachment adjusts the oscillation angle dynamically, taking into account the current power consumption of the attachment and/or as a function of the casing depth or the excavation depth. In this way, the working process or the effectiveness of the casing-making machine can be optimized in a targeted manner, since an optimal, maximum oscillation angle can be set taking into account the aforementioned variables.

Of further importance is the soil strength at the current place of work. This factor can also be taken into account for the optimal setting of the attachment or the carrier machine. In particular, if the casing machine is not propelling you well, an additional piece of pipe can be installed to increase the contact pressure. It is also conceivable that in such a case the casing oscillator specifically requests more energy for the casing process from the carrier machine via the communication interface. The casing machine can determine the current feed rate, for example, taking into account the change in the depth of the casing over time.

In addition to the method according to the invention, the present invention also relates to a system for pile foundations according to claim 13, consisting of a carrier machine, in particular a cable excavator or drilling device, and at least one attachment, preferably a casing or pipe lathe. The attachment or the carrier machine comprise at least one controller, the controller of the carrier machine being designed to carry out the method according to the invention. According to the invention, the control of the method is taken over by a control of the carrier machine. Accordingly, the system is distinguished by the same advantages and properties as have already been explained in detail above with reference to the method according to the invention. For this reason, a repeated description is dispensed with.

Figur 1:

eine Seitenansicht des erfindungsgemäßen Systems bestehend aus einer Trägermaschine sowie einer Verrohrungsmaschine;

Figur 2:

eine Seiten- und Draufsicht auf die Verrohrungsmaschine;

Figur 3:

eine Diagrammdarstellung zur Verdeutlichung der Kostenfunktion in Abhängigkeit der Tiefendifferenz zwischen Verrohrungstiefe und Aushubtiefe und

Figuren 4a, 4b:

zwei Diagrammdarstellungen der Aushub- bzw. Verrohrungstiefe gegenüber der Zeit.

Further advantages and properties of the invention are to be explained in more detail below with reference to an exemplary embodiment illustrated in the figures. Show it:

Figure 1:

a side view of the system according to the invention consisting of a carrier machine and a casing machine;

Figure 2:

a side and plan view of the casing machine;

Figure 3:

a diagram to illustrate the cost function as a function of the depth difference between casing depth and excavation depth and

Figures 4a, 4b:

two plots of excavation or casing depth versus time.

The creation of piles using a casing machine (VRM) in combination with a cable excavator (grab drilling) or a drilling rig (Kelly drilling) should be optimized by an assistant in terms of energy (fuel consumption) and the time required. The assistant dynamically regulates the distribution of energy between the VRM and the base machine in order to optimize the utilization and effectiveness of the two machines.

When grab drilling with a VRM, two independent devices, namely a cable excavator 1 and the cable excavator's attachment in the form of the casing oscillator, work together to create a pile. Like in the figure 1 is shown as an example, the cable excavator 1 with a rotatable superstructure, a boom 2 and a gripper 3 takes over the digging of a hole. A casing-making machine is attached to the cable excavator, consisting of a base plate 201 and a table 301, which can be adjusted at a distance from the base plate 201. With this casing-making machine, a casing 100 can be driven into the ground as follows: the table 301 is secured with the casing, for example with the aid of a clamping cylinder 100 locked. Subsequently, the base plate 201 is raised, whereby the weight of the piping 100, the table 301 and the base plate 201 acts downward. In order to overcome the static friction, the table 301 is set in motion in a further step, for example in horizontal oscillations (so-called casing machines) or in continuous rotation (so-called pipe lathes). Through this interaction, the casing 100 descends into the ground while the dragline 1 dredges the soil within the casing 100 .

With more details, the casing machine is in the Figures 2a, 2b 10 are shown showing the casing stringing machine 100 in side and plan views. The table 301 can be clamped to the tube 100 by means of clamps, for example. The base plate 201 can be raised between the connection points 211/311 and 212/312 via lifting cylinders. The table 301 can rotate relative to the base plate 201 by synchronized movements of the two oscillator cylinders between the connection points 313/413 and 314/414. A rigid steering rod is articulated on the one hand at point 321 on table 301 and on the other hand articulated to element 401 at point 421. By moving a steering cylinder, which is articulated to the steering rod at point 415 on the one hand and articulated to the base plate 201 at point 215 on the other hand, the inclination of the tubing 100 can be adjusted around the y-axis of the tubing 100 about the x-axis. The pivot points 413, 414 and 421 can be moved horizontally by means of a guide 401 relative to the structure 202, which is fixedly connected to the table 201. The inclination of the table 301 can be detected by means of the inclination sensor 501, in particular in order to be able to align it for the desired pole inclination. The inclination or angle sensor 502 detects the position of the steering rod, in particular for determining the casing depth.

The energy expenditure for creating a pile is made up of the power required by the carrier machine (cable dredger, drilling rig) for digging the borehole and the power required by the VRM to insert the casing 100 . The casing 100 is twisted by the VRM using the weight of the casing 100 and the VRM in conjunction with a rotary motion. The screwing-in process of the VRM is quite energy-intensive due to the surface and tip friction. The peak friction is also determined by the nature of the ground and the design of the casing 100 . Skin friction is caused by the relative movement of casing 100 to the ground along the outer surfaces of casing 100. Skin friction has two components, first, friction on the outside of casing 100 and second, friction on the inside of casing 100. Friction on the outside increases as the well progresses due to the increasing contact area between the casing 100 and the ground with increasing depth. However, the friction on the inside of the casing 100 can be virtually eliminated by minimizing the protrusion of the casing 100 as the excavation progresses.

The drill cuttings are removed from the casing 100 with the aid of the cable excavator 1 (grab drilling) or a drill. By far the greatest power requirement of the cable excavator 1 or the drilling device occurs when the drilling tool 3 is raised.

This expenditure of energy and time increases with the depth of the borehole due to the increasing lifting height.

The power requirement can be optimized by dynamically controlling the energy flow between the base machine and the VRM. The control can be controlled by the carrier machine, for example. It is possible that the carrier machine completely stops, maximizes or continuously regulates the energy flow. Alternatively, the carrier machine can request a change in the power requirements of the VRM via a communication interface from the VRM or, for example, specify that certain work steps may not be carried out or are not recommended (especially recommended when operating the VRM with an additional power pack - energy source).

• Hoher Eigenbedarf
  • ∘ Die Trägermaschine erkennt wann für beispielsweise das Heben des Bohrwerkzeuges 3 und des Bohrgutes viel Energie aufgewendet werden muss und reduziert den Energiefluss zur VRM oder stoppt diesen für die benötigte Zeitdauer (komplette Eliminierung von Verlusten in der VRM).
• Geringer Eigenbedarf
  • ∘ Die Trägermaschine erkennt wann die Energieauslastung für die seitens der Trägermaschine auszuführenden Arbeiten gering ist und erhöht den Energiefluss zur VRM bzw. startet die VRM für die maximal mögliche Zeitdauer.
• Ungleicher Fortschritt
  • ∘ Eine mögliche Vorgabe aufgrund lokaler Gegebenheiten kann sein, dass etwa die Verrohrung 100 immer ein gewisses Mindestmaß vor der Aushebung des Bohrloches ist. Wenn beispielsweise die Aushebung der Verrohrung 100 vor eilt, so ist es möglich, dass etwa die Verrohrung 100 abstürzt und damit Schäden und Kosten verursacht. Wenn allerdings die Verrohrung 100 zu stark vor eilt, wird die Mantelreibung auf der Innenseite zu groß. Entsprechend sollte der Fortschritt in etwa gleich schnell stattfinden mit einer vorgegebenen Differenz.
  • ∘ Erkennt die Trägermaschine 1, dass der Fortschritt der Verrohrung 100 gegenüber dem Aushub zu groß ist, so wird der Energiefluss zur VRM reduziert oder gestoppt, bis der Fortschritt des Aushubes wieder in "Reichweite" der Verrohrung 100 kommt. In Folge steht der Trägermaschine 100 für diesen Zeitraum mehr Leistung zur Verfügung, wodurch der Aushub schneller vorankommt. Darüber hinaus wird der gesamte Leistungsbedarf für das Eindrehen der Verrohrung 100 reduziert, da es durch eine Reduktion des verringerten Vorsprunges der Verrohrung 100 zu einer Reduktion der Mantelreibung kommt.
• Ungünstiger Oszillationswinkel
  • ∘ Aufgrund der Geometrie einer typischen VRM ergibt sich ein optimaler Wirkungsgrad der Kraftübertragung bei einer bestimmen Stellung der beiden Oszillierzylinder. Bei großen Abweichungen in beide Richtungen nimmt der Wirkungsgrad ab.
  • ∘ Beim Wechsel der Drehrichtung kommt die Verrohrung 100 zum Stillstand. Nun müssen die beiden Oszillierzylinder die Haftreibung überwinden, erst dann kommt wieder die geringere Gleitreibung zum Tragen.
  • ∘ Ein weiterer Effekt, der hierbei eine Rolle spielt: bei sehr großen Tiefen reduziert sich der effektive Oszillationswinkel an der Front der Verrohrung 100 aufgrund von Verwindung der Verrohrung 100.
  • ∘ Aufgrund dieser drei Randbedingungen gibt es also eine Art optimalen, maximalen Oszilierwinkel, der von der Tiefe der Verrohrung 100 abhängt. Um also den Prozess zu optimieren, kann durch eine Messung der Tiefen der Verrohrung und des Aushubes sowie durch eine zusätzliche Messung der Leistungsaufnahme der VRM ein optimaler, maximaler Oszilierwinkel eingestellt werden.
• Hohe Bodenfestigkeit
  • ∘ Bei schlechtem Vortrieb der VRM kann diese ein weiteres Rohrstück zur Erhöhung des Anpressdruckes bzw. die Bereitstellung von mehr Energie von der Trägermaschine anfordern.

An optimization of the process results with regard to the following cases:

• High personal needs
  • ∘ The carrier machine recognizes when a lot of energy has to be used, for example to lift the drilling tool 3 and the drill cuttings, and reduces the energy flow to the VRM or stops it for the required period of time (complete elimination of losses in the VRM).
• Low personal requirements
  • ∘ The carrier machine recognizes when the energy utilization for the work to be carried out by the carrier machine is low and increases the energy flow to the VRM or starts the VRM for the maximum possible period of time.
• uneven progress
  • ∘ A possible specification based on local conditions can be that the casing 100 is always a certain minimum dimension before the borehole is dug. For example, if the casing 100 is excavated ahead of time, it is possible that the casing 100 may fall, causing damage and costs. However, if the casing 100 advances too much, skin friction will increase too big on the inside. Accordingly, the progress should take place at about the same speed with a given difference.
  • ∘ If the carrier machine 1 recognizes that the progress of the casing 100 compared to the excavation is too great, the flow of energy to the VRM is reduced or stopped until the progress of the excavation comes within "range" of the casing 100 again. As a result, the carrier machine 100 has more power available for this period of time, which means that the excavation progresses more quickly. In addition, the total power requirement for screwing in the casing 100 is reduced since a reduction in the reduced projection of the casing 100 results in a reduction in the skin friction.
• Unfavorable oscillation angle
  • ∘ Due to the geometry of a typical VRM, there is an optimal efficiency of the power transmission with a certain position of the two oscillating cylinders. With large deviations in both directions, the efficiency decreases.
  • ∘ When changing the direction of rotation, the casing 100 comes to a standstill. Now the two oscillating cylinders have to overcome the static friction, only then does the lower sliding friction come into play again.
  • ∘ Another effect that plays a role here: at very great depths, the effective oscillation angle at the front of the casing 100 is reduced due to twisting of the casing 100.
  • ∘ Because of these three boundary conditions, there is a type of optimum, maximum oscillation angle that depends on the depth of the casing 100 . In order to optimize the process, an optimal, maximum oscillation angle can be set by measuring the depths of the casing and the excavation as well as by additionally measuring the power consumption of the VRM.
• High soil strength
  • ∘ If the VRM's propulsion is poor, it can request another piece of pipe to increase the contact pressure or to provide more energy from the carrier machine.

• Für die Optimierung bei ungleichem Fortschritt: Tiefenmessung der Verrohrung und Tiefenmessung des Aushubes
• Für die Optimierung des Oszillationswinkels: Messung Oszillationswinkel (Drehwinkelsensor in einem der Gelenke der Lenkstange bzw. weniger ideal in einem der Gelenke der Oszillierzylinder)

requirements

• For optimization in the event of uneven progress: depth measurement of the casing and depth measurement of the excavation
• To optimize the oscillation angle: Measurement of the oscillation angle (angle of rotation sensor in one of the steering rod joints or, less ideally, in one of the oscillation cylinder joints)

• Mehr Energie für die zu priorisierende Tätigkeit → Zeitoptimierung
• Durch Zeitgewinn weniger Verbrauch (Stichwort Grundlast / Verluste)
• Durch Zeitgewinn weniger Betriebsstunden

Advantages:

• More energy for the activity to be prioritized → time optimization
• Less consumption due to time gain (keyword base load / losses)
• Less operating hours thanks to time savings

Application examples:

• Die Verrohrungsmaschine hat gemessen, dass eine Verrohrung 100 eine bestimme Anzahl von Metern unter der Erde ist. Durch die Seillängenmessung des Seilbaggers 1 ist auch die Tiefe des Aushubes bekannt sowie durch einen Abgleich der Seillänge mit der Rohroberkante lässt sich auf die verbleibende Höhe der Verrohrung oberhalb der Verrohrungsmaschine schliessen. Die Verrohrung 100 ist nun beispielsweise 20 Meter unter der Erde, der Aushub 19 Meter, es stehen noch 4 Meter Rohr zum Eindrehen zur Verfügung. Aufgrund der lokalen Begebenheiten muss die Verrohung mindestens einen Meter dem Aushub vor eilen. Entsprechend sollte nun der Prozess des Eindrehens durch die VRM schneller werden, wohingegen der Aushubprozess des Seilbaggers 1 langsamer erfolgen kann. Um nun die Zeit effizient zu nutzen, einigen sich die beiden Maschinensteuerungen darauf, dass der Seilbagger 1 ein weiteres Rohr aufsetzt bzw. dies dem Bediener vorschlägt. In diesem Fall benötigt der Seilbagger 1 wenig Energie, durch die freigewordene Energie kann die VRM schneller vorankommen. Als zusätzlicher positiver Effekt erhöht sich durch das zusätzliche Teilstück das Eigengewicht der Verrohrung und das Eintreiben wird auch hierdurch beschleunigt.

The placement of a further piece of pipe on the casing 100 by the carrier machine 1 is a lengthy process in which the carrier machine 1, however, requires very little energy. The digging tool 3 is laid aside, a length of tubing 100 is attached to the cable, placed over the existing tubing and then locked to the remaining tubing. A lot of energy is available to the casing oscillator, especially during the first part of this process. The following examples can now be derived from this:

• The casing machine has measured that a casing string 100 is a certain number of meters underground. The depth of the excavation is also known from the cable length measurement of the cable excavator 1, and by comparing the cable length with the upper edge of the pipe, the remaining height of the casing above the casing-making machine can be deduced. The casing 100 is now, for example, 20 meters underground, the excavation 19 meters, there are still 4 meters of pipe available for screwing in. Due to the local conditions, the casing must precede the excavation by at least one meter. Accordingly, the screwing-in process by the VRM should now be faster, whereas the excavation process of the cable excavator should be faster 1 can be done more slowly. In order to use the time efficiently, the two machine controls agree that the cable excavator 1 puts on another pipe or suggests this to the operator. In this case, the cable excavator 1 requires little energy, and the energy released allows the VRM to move faster. As an additional positive effect, the additional section increases the dead weight of the tubing and this also speeds up driving in.

• Der Seilbagger 1 fährt mit dem Werkzeug 3 in die Verrohrung 100 und gräbt sich unten Material frei. Als nächstes muss der Seilbagger 1 das mit Aushub gefüllte Werkzeug 3 anheben. Dieser Umstand kann im Vorhinein bereits der VRM mitgeteilt werden. Sobald der Seilbagger 1 das Werkzeug 3 anhebt kann die Energiezufuhr zur VRM reduziert werden. Die VRM nutzt diese Zeit für eine energetisch günstigere Arbeit, wie etwa das Anheben der Bodenplatte 201. Sobald das Werkzeug 3 die Rohroberkante erreicht hat, meldet der Seilbagger 1 der VRM, dass der Hub vorbei ist und erhöht entsprechend den Energiefluss zur VRM, wodurch diese nun wieder mit voller Energie die eingespannte Verrohrung drehen kann.
• Bei ungünstiger Verteilung der Tiefen (wenn etwa die VRM viel tiefer ist als der Aushub und entsprechend die Mantelreibung an der Innenseite der Verrohrung recht hoch ist) kann im Extremfall die Energiezufuhr zur VRM für die Dauer des Aushubs komplett gestoppt werden.

During the raising of the digging tool 3, the carrier machine requires a great deal of energy, and the oscillation of the VRM also requires a great deal of energy. Another application example can be derived from this:

• The cable excavator 1 moves into the casing 100 with the tool 3 and digs material free at the bottom. Next, the cable excavator 1 has to lift the tool 3 filled with excavation. VRM can be informed of this fact in advance. As soon as the cable excavator 1 lifts the tool 3, the power supply to the VRM can be reduced. The VRM uses this time for more energy-efficient work, such as lifting the bottom plate 201. As soon as the tool 3 has reached the top edge of the pipe, the cable excavator 1 reports to the VRM that the lift is over and correspondingly increases the energy flow to the VRM, causing it can now turn the clamped casing with full energy again.
• If the depths are unfavorably distributed (e.g. if the VRM is much deeper than the excavation and the skin friction on the inside of the casing is correspondingly high), in extreme cases the energy supply to the VRM can be stopped completely for the duration of the excavation.

• Der Seilbagger 1 kommt mit größer werdender Tiefe nur mehr langsam mit dem Aushub voran. Der Vorsprung der Verrohrung 100 steigt dadurch kontinuierlich an. Aufgrund dessen kann der Seilbagger 1 die Energiezufuhr zur VRM drosseln, um mehr Energie für die eigene Tätigkeit zur Verfügung zu haben.
• Bei ungünstiger Verteilung der Tiefen (wenn etwa die VRM viel tiefer ist als der Aushub und entsprechend die Mantelreibung an der Innenseite der Verrohrung recht hoch ist) kann im Extremfall die Energiezufuhr zur VRM zeitweise komplett gestoppt werden (siehe Beispiel in Figur 4b).

The time required for raising the excavation tool 3 increases steadily with depth. This results in an increased time required to remove a given amount of cuttings at great depths. As a result, the work of the carrier machine 1 proceeds more slowly at great depths. However, the time it takes the VRM to run per meter of casing 100 does not increase proportionally with depth. From this it can be deduced:

• With increasing depth, the cable excavator 1 progresses only slowly with the excavation. As a result, the projection of the tubing 100 increases continuously. Because of this, the cable excavator 1 can throttle the energy supply to the VRM in order to have more energy available for its own work.
• If the distribution of the depths is unfavorable (if, for example, the VRM is much deeper than the excavation and the skin friction on the inside of the casing is correspondingly high), the energy supply to the VRM can be temporarily stopped completely in extreme cases (see example in Figure 4b ).

concrete method

• Prozessoptimierung:
  • ∘ Der Bediener der VRM stellt eine minimale Tiefendifferenz D_min ein. Beim gleichzeitigen Verrohren und Ausgraben mittels Greifer 3 darf der Greifer 3 diese minimale Tiefendifferenz nicht unterschreiten (bsp: D_min=40 cm, also muss die Verrohrung 100 immer mindestens 40cm dem Greifer 3 vor eilen). Es gibt kein D_max , die Verrohrung 100 darf dem Greifer 3 beliebig weit voreilen.
  • ∘ Es wird nun eine Kostenfunktion U als Funktion der Tiefendifferenz D formuliert mit einem Minimum D₀ > D_min. Siehe hierzu Figur 3. Bei D₀ ist die Energieverteilung R ideal.
  • ∘ Ist nun D kleiner als D₀, dann steigt der Leistungsanteil R, den der Seilbagger 1 der VRM zur Verfügung stellt. Das hat zwei Effekte: die VRM bekommt mehr Leistung, dreht damit schneller und vergrößert dadurch D, andererseits hat der Seilbagger 1 weniger Leistung, verringert damit seine Grabgeschwindigkeit, was auch eine Vergrößerung von D zur Folge hat. Sollte D kleiner als D₀ sein und die an die VRM bereitgestellte Energie bereits maximal sein, so muss das Gewicht der Verrohrung zur Erhöhung des Anpressdruckes vergrößert werden, so bspw. durch Aufsetzen eines weiteren Teilrohres.
  • ∘ Ist D größer als D₀, dann wird der Leistungsanteil R, den der Seilbagger 1 der VRM zur Verfügung stellt, verringert. Der Leistungsanteil R berechnet sich folglich nach der Formel R = PVRM / P, wobei PVRM der Anteil an der Gesamtleistung P ist, die der VRM zur Verfügung steht aufgrund der Prozessoptimierung.
  • ∘ Wenn sich D nahe an D_min annähert, sollte die VRM gestoppt werden.
• Optimierung der Maschinenauslastung:
  • ∘ Von der obigen Prozessoptimierung wird eingestellt, wie groß der mittlere Anteil der Leistung ist, den der Seilbagger 1 der VRM zur Verfügung stellt. In weiterer Folge wird nun dieser Parameter R mit einem weiteren Parameter R_cyc multipliziert, der den zyklischen Grabprozess des Seilbaggers 1 berücksichtigt. Die Leistungsaufteilung ergibt sich beispielsweise als Q = R × R_cyc. Rcyc ist demzufolge ein Korrektur- bzw. Gewichtungsfaktor des Leistungsanteil der VRM aufgrund der Auslastung des Seilbaggers 1, der üblicherweise im Werteintervall zwischen 0 bis 1 liegt
  • ∘ Der Seilbagger 1 benötigt am meisten Leistung während des Grabens und während des Hebens. In dieser Zeit sollte der Seilbagger viel Leistung bekommen, die VRM bekommt während diesem Zeitraum eine geringere Leistung. R_cyc wird also < 1 sein, bis zu einem extremen Fall R_cyc = 0 (VRM bekommt gar keine Leistung mehr).
  • ∘ Der Seilbagger 1 benötigt eine geringe Leistung während des Entleerens des Greifers 3 und während dem Absenken des Greifers 3 in das Bohrloch. In dieser Zeit kann die VRM einen größeren Leistungsanteil erhalten ohne den Prozess zu verlangsamen, entsprechend wird ein R_cyc ~ 1 gewählt.
  • ∘ Ein energetisch optimaler Zustand liegt dann vor, wenn der Abstand zwischen den Linien der Figuren 4a, 4b minimal ist.

Two different procedures are carried out in parallel:

• Process Optimization:
  • ∘ The operator of the VRM sets a minimum depth difference D _min . When casing and excavating using grab 3 at the same time, grab 3 must not fall below this minimum depth difference (e.g. D _min =40 cm, i.e. casing 100 must always be at least 40 cm ahead of grab 3). There is no D _max , the casing 100 may lead the grab 3 as far as desired.
  • ∘ A cost function U is now formulated as a function of the depth difference D with a minimum D ₀ > D _min . See also figure 3 . At D ₀ the energy distribution R is ideal.
  • ∘ If D is now smaller than D ₀ , then the power share R, which the duty-cycle crane 1 makes available to the VRM, increases. This has two effects: the VRM gets more power, turns faster and thus increases D, on the other hand the cable excavator 1 has less power, thus reducing its digging speed, which also results in an increase in D. If D is less than D ₀ and the energy provided to the VRM is already at its maximum, the weight of the tubing must be increased to increase the contact pressure, for example by attaching an additional partial tube.
  • ∘ If D is greater than D ₀ , then the power component R, which the duty-cycle crane 1 makes available to the VRM, is reduced. The power share R is calculated according to the formula R = PVRM / P, where PVRM is the share of the total power P that is available to the VRM due to the process optimization.
  • ∘ When D approaches close to _Dmin , the VRM should be stopped.
• Optimization of machine utilization:
  • ∘ From the process optimization above, it is set how large the average portion of the power is that duty cycle crane 1 makes available to the VRM. Subsequently, this parameter R is now multiplied by a further parameter R _cyc , which takes into account the cyclic digging process of the cable excavator 1 . The power distribution results, for example, as Q=R×R _cyc . Accordingly, Rcyc is a correction or weighting factor of the power component of the VRM due to the utilization of the cable excavator 1, which usually lies in the value interval between 0 and 1
  • ∘ Dragline 1 requires the most power during digging and lifting. During this time, the cable excavator should get a lot of power, the VRM gets less power during this period. R _cyc will therefore be < 1, up to an extreme case R _cyc = 0 (VRM no longer gets any power at all).
  • ∘ The cable excavator 1 requires little power while emptying the grab 3 and while lowering the grab 3 into the borehole. During this time, the VRM can receive a larger proportion of power without slowing down the process, so an R _cyc ~ 1 is chosen accordingly.
  • ∘ An energetically optimal state exists when the distance between the lines of the Figures 4a, 4b is minimal.

Claims (13)

1. Method of power management during pile foundation having a base machine (1) for excavating a borehole and an attachment installed at the base machine (1) for a simultaneous introduction of a casing (100) into the ground, wherein the energy supply for the attachment is at least partially provided by the base machine (1),
   characterized in that
   a control unit of the base machine (1) distributes the flow of energy between the base machine (1) and the attachment for hydraulic, pneumatic or electric supply of energy of the attachment, wherein a dynamic control of the flow of energy takes place in consideration of the current power demand of the base machine (1) and/or of the attachment in order to optimize capacity utilization and effectivity of the base machine and of the attachment.
2. Method in accordance with claim 1, characterized in that the energy flow to the attachment is limited or completely stopped, wherein a limitation can take place stepwise or continuously.
3. Method in accordance with one of the preceding claims, characterized in that the control unit of the base machine (1) communicates a request for a power reduction to the attachment over a communication interface.
4. Method in accordance with claim 3, characterized in that the request includes an instruction on work steps of the attachment to be carried out, in particular a specification and/or recommendation with respect to work steps to be carried out and/or not to be carried out.
5. Method in accordance with one of the preceding claims, characterized in that the process time for work steps of the attachment and/or of the base machine (1) is actively controlled by means of the dynamic regulation of the energy flow.
6. Method in accordance with one of the preceding claims, characterized in that the depth difference between the depth of the earth excavation and the casing depth is taken into account for the dynamic regulation, wherein the depth difference is preferably held above and/or below a lower and/or higher limit value by the dynamic regulation of the energy flow.
7. Method in accordance with claim 6, characterized in that the energy flow to the attachment is restricted if the casing depth is larger by at least a limit amount than the excavation depth, and/or the energy flow to the attachment is increased or maximized if the excavation depth is larger by at least a limit amount than the casing depth.
8. Method in accordance with one of the preceding claims 6 or 7, characterized in that a cost function U is defined as a function of the depth difference that defines the average power proportion to be output to the attachment in dependence on the depth difference.
9. Method in accordance with claim 8, characterized in that the energy flow to the attachment is dynamically set on the basis of the average power proportion while further taking account of the cyclic excavation process of the base machine (1), in particular by multiplying the average power value by a weighting parameter that characterizes the current process step during a cyclic excavation process.
10. Method in accordance with claim 9, characterized in that the weighting parameter is smaller during the digging and lifting of the excavation tool (3) and is larger during the lowering and emptying of the excavation tool (3).
11. Method in accordance with one of the preceding claims, characterized in that the attachment sets the oscillation angle of the attachment configured as a casing oscillator while taking account of the current power consumption of the attachment and/or in dependence on the casing depth and/or in dependence on the excavation depth.
12. Method in accordance with one of the preceding claims, characterized in that the attachment detects the advance speed of the casing (100), in particular while taking account of the depth change of the casing (100) over time and based thereon requests an increase of the energy flow from the base machine (1) to the attachment over the communication interface and/or initiates a work process to place a further pipe onto the casing.
13. System for pile foundation, consisting of a base machine (1), in particular a cable excavator or a drilling rig, and at least one attachment, preferably a casing oscillator or a casing rotator, wherein the base machine (1) comprises at least one control unit and the control unit is configured to carry out the method in accordance with one of the preceding claims 1 to 12.

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