AU2019294387B2

AU2019294387B2 - Energy-efficient control of a device for continuously conveying material

Info

Publication number: AU2019294387B2
Application number: AU2019294387A
Authority: AU
Inventors: Matthias KALTHOFF; Viktor Raaz
Original assignee: Koch Solutions GmbH
Current assignee: Koch Solutions GmbH
Priority date: 2018-06-28
Filing date: 2019-06-26
Publication date: 2022-08-11
Anticipated expiration: 2039-06-26
Also published as: DE102018115645A1; WO2020002407A1; AU2019294387A1

Abstract

The invention relates to a control system (2) for a device (1) for continuously conveying material, comprising a working element (101) which is designed to receive material (M) and which can be moved relative to an underlying surface (U) by at least one drive (12-14) in successive work processes, wherein the control system (1) is designed to detect at least one value of an output and/or energy received by at least one drive (12-15) of the device (1) during a work process and to ascertain the degree of energy efficiency for the working process using the at least one value of the received output and/or energy.

Description

ENERGY-EFFICIENT CONTROL OF A DEVICE FOR CONTINUOUSLY CONVEYING MATERIAL TECHNICAL FIELD

[0001] The present invention relates to embodiments of a control system for an apparatus for continuously conveying material. The invention furthermore relates to embodiments of a method for controlling an apparatus for continuously conveying material.

BACKGROUND

[0002] Apparatuses for continuously conveying material are used worldwide for the reclaiming of stockpile material at storage sites or for the extraction of materials by mining. Such apparatuses for continuous reclaiming and/or extraction of material will hereinafter also be referred to as loaders. In the case of a continuously working loader, for example a bucket wheel excavator or a bucket wheel reclaimer, the material for loading is, by means of a continuously moving working element (for example a bucket wheel, a bucket or scraper chain, a milling drum etc.), removed at regular intervals from the stockpile or from the rock mass, collected in buckets or so-called pockets, lifted, and placed onto a conveyor belt for onward transport. Here, a working process of such a loader is generally made up of a combination of successively alternating feed and advancing (or advance) movements whilst the working element moves continuously to pick up material. The working processes may be repeated cyclically. In the case of bucket wheel reclaimers and bucket wheel excavators, the advancing movement is commonly performed as a pivoting movement for example of a boom about a pivot axis, whereas the feed movement is performed as a (linear) forward traveling movement, in particular such that the pivot axis is displaced along an axis of forward travel. In the process, the working element rotates continuously, for example on the boom. In the case of other loaders, the advancing movement is performed as a linear advancing movement, and the feed movement is performed as a pivoting movement.

[0003] Loaders generally comprise a substructure and a superstructure. The substructure typically comprises an undercarriage. The superstructure is mounted on the substructure and

18216646_1 (GHMatters) P115070.AU bears the working element. The feed movement (in particular forward traveling movement) of the loader is commonly performed by means of the undercarriage and in an excavating direction of the respective excavation block. The feed movement typically takes place in the direction of travel of the undercarriage.

[0004] Between two feed movements, the substructure of the loader stands stationary on the ground, whilst the superstructure with working element (for example a bucket wheel) rotating thereon is pivoted laterally over the entire excavation block width about the vertical pivot axis (for example of the boom relative to the substructure). In the process, the depth to which the working element penetrates into the front slope of the material changes in accordance with the advancing position (in this case the pivot angle of the boom relative to the substructure about the pivot axis). The depth of penetration can be calculated in accordance with a corresponding function, which includes for example the cosine of the pivot angle phi. In combination with a variable excavation height, it is thus possible to determine an advancing position-dependent change in a lateral cutting cross-sectional area of the working element. In order to obtain a constant conveying rate, it is possible to implement control of the advancing speed in a manner dependent on the advancing position, which control counteracts the change in the lateral cutting cross-sectional area. This advancing position control is performed by means of a control unit. As input variables, the control unit receives the advancing position (for example the pivot angle), the feed parameter (for example the forward travel position or the step length), and a layer height or stockpile height of the excavation block. From these, the control unit calculates a cutting area and a feed parameter and/or a required advancing speed in order to maintain a constant predetermined conveying flow (material per unit of time).

[0005] Such control can be referred to as "cosine-phi closed-loop control". The pivoting speed of the working element (relative to the substructure) can, for example in the case of bucket wheel excavators, be controlled in closed-loop fashion in a manner approximately proportional to the reciprocal of the cosine value of the pivot angle. In the case of bucket wheel reclaimers, such closed-loop control is generally more complex, because the stockpile or layer height can vary greatly over the pivot angle range, for example owing to shallow side slopes, owing to remaining interstices, and the like.

[0006] The invention disclosed herein improves the control of an apparatus for continuously conveying material as defined above.

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SUMMARY OF THE INVENTION

[0007] In particular, in one aspect, the invention provides an apparatus for continuously conveying material comprising a working element which is designed for picking up material and which is movable in multiple successive working processes relative to an underlying surface by at least one drive of the apparatus, the apparatus having a control system for achieving controlled movement of the working element in an optimized manner as noted hereinbelow.

[0008] Accordingly, the control system is designed and provided to detect at least one value of a power (in particular electrical power) and/or energy consumed (in particular overall) by at least one drive of the apparatus during a working process, in particular for multiple successive working processes; and to ascertain an energy efficiency for the working process on the basis of the at least one value of the consumed power and/or energy. For this purpose, the control apparatus can be connected or is connectable to the apparatus for the purposes of exchanging data.

[0009] The maximum and/or demanded conveying performance of the apparatus (of a loader) can be attained for example with different settings of feed parameters (for example forward travel positions) and advancing speeds (for example pivoting speeds). It has been found that the total drive power required here, in particular the energy requirement of the drives for a complete working process, can vary considerably with the settings even for the same conveying performance. For a particular excavation situation, it is thus possible to find an optimum feed position which corresponds to a minimum energy requirement. The value of this optimum feed position may in particular be dependent on the characteristics of the material excavated / picked-up, on the working element geometry, on the block geometry or excavation height, and on the demanded conveying rate. Mutual dependencies between these variables are generally complex and make an exact prediction difficult. The control system proposed by the invention therefore detects actual values for the energy consumption and thus ascertains an actual energy efficiency. On the basis of this ascertained energy efficiency, it is possible to select particularly energy-saving settings and convey a predefined quantity of material in an energy-saving manner. Since the energy used has a direct influence on the wear of the apparatus, in particular of the working element, not only is it possible for the energy

18216646_1 (GHMatters) P115070.AU consumption to be reduced, but it is also possible for the wear of the apparatus to be reduced. In this way, maintenance intervals can be lengthened.

[0010] Accordingly, in one specific aspect of the invention, there is provided a control system of an apparatus for continuous reclaiming and/or extracting and subsequent conveying of material from a stockpile or a solid mass of such material, such as a bucket wheel excavator or reclaimer, the apparatus having a working element configured for continuously picking up said material and which is movable in successive working processes relative to an underlying surface by at least separate feed and advance drives, each of said working processes comprising a combination of alternating feed and advance movements of the working element and whilst the working element moves continuously in the process of picking up said material, wherein the control system is configured to: - detect at least one value of a power and/or energy consumed by the separate feed and advance drives of the apparatus during one of the working processes; - ascertain an energy efficiency for the one working process on the basis of the at least one value of the consumed power and/or energy, by calculating a ratio of the energy consumed by the feed and advance drives to a feed value of the working process; and - in a manner dependent on the energy efficiency ascertained for the one working process, provide control data relating to a working process subsequent to the one working process, to operate the apparatus.

[0011] The working element is for example a bucket wheel. The working element is designed to excavate material, in particular raw materials, and/or remove material stored on a stockpile, for example in the form of bulk material. As noted, the apparatus is for example a bucket wheel excavator or a bucket wheel reclaimer.

[0012] In one embodiment, where the working element itself also comprises a drive separate from the feed and advancing drives, such as in the already mentioned bucket wheel excavator or bucket wheel reclaimer, in order to ascertain the energy efficiency, the ratio of the energy consumed by the drives to the feed value of the working process is calculated, namely the ratio of the entire energy consumed by the working element, feed and advancing drives within a working process to a feed value of that working process. The feed value is for example a length. Said ratio has for example the unit J/m or kWh/m.

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[0013] As noted, the control system is designed to, in a manner dependent on the energy efficiency ascertained for the at least one working process (in particular for multiple working processes), provide control data relating to a subsequent working process to the apparatus. The control system can for example ascertain particularly energy-saving parameter values and induce the apparatus to perform a working process or multiple working processes with the energy-saving parameter values. The control system in turn ascertains the energy efficiency in these working processes too. The control system can thus provide closed-loop control which adjusts one or more settings of the apparatus to the most energy-efficient values possible.

[0014] The control system may furthermore be designed to receive sensor data (in particular from the apparatus) and calculate the control data in a manner dependent on the sensor data. The sensor data may for example comprise, beyond the power consumed by the advancing and feed drives of the apparatus, a material mass picked up by means of the working element, a material volume picked up by means of the working element, environmental data, measured values relating to a stockpile geometry or rock geometry. The real stockpile geometry or excavation block geometry often differs from a previously set or ascertained geometry. The advance (or advancing) and feed control in transition regions (in particular at the start of the stockpile, at the end of the stockpile, in the case of settling effects, as a result of a slope failure etc.) is adaptable to the local conditions by means of the control system. It is thus possible for demanded conveying performance to be attained over the entire conveying time. The control system may be designed to be adaptive and measure the real stockpile or slope geometry immediately before and after the excavation by means of a distance sensor (for example by means of radar, laser or ultrasound), ascertain a present cutting cross section, and readjust the advancing speed. Alternatively, adaptive closed-loop control by means of the measurement of a volume flow of the material is possible. For example, the advancing speed is controlled in closed-loop fashion in a manner dependent on a measured volume flow. It is for example possible for a pivoting speed rule to be adapted to a measured volume flow. By means of the sensor data, it is possible for the control system to be formed as an adaptive closed-loop control. Optionally, the control system itself comprises the corresponding sensors.

[0015] Optionally, the control system is designed to, for the ascertainment of the energy efficiency, determine an energy efficiency coefficient. The energy efficiency coefficient is for example equal to the value of the energy consumed (stated in joules or in kilowatt-hours), in particular the entire energy consumed by working element, feed and advancing drives within a working process divided by a total volume (stated for example in cubic meters) or a total

18905140_1 (GHMatters) P115070.AU mass (stated for example in tons) of material, in particular of the material picked up during the working process. The lower the energy efficiency coefficient, the higher the efficiency. The energy efficiency coefficient has for example the unitJm3 ,Jt, kWh/m3 or kWh/t.

[0016] In one refinement, the drive power consumed by the advancing drive, the feed drive, a bucket wheel drive and/or a conveyor belt drive of the apparatus, in particular all of the stated drives, optionally all drives of the apparatus, is used for the determination of the energy efficiency coefficient. The working element on the apparatus can be moved by means of the working element drive. The working element drive is for example a bucket wheel drive. By means of the advancing drive, the working element can be advanced along the material to be picked up. During the advancement, the working element picks up material. By means of the feed drive, the working element, optionally the entire apparatus, is movable relative to the underlying surface between two advancing movements. The working element picks up no material or little material during the feed movement. By means of the conveyor belt drive, a conveyor belt is set in circulating motion in order to transport away the material picked up by the working element.

[0017] In one embodiment, the control system is furthermore designed to, through variation of at least one variation parameter over several working processes, ascertain at least one optimized variation parameter, by means of which the energy efficiency is increased in relation to other values of the variation parameter, that is to say the energy efficiency coefficient is minimized. The actual efficiency can thus be ascertained and gradually improved during the ongoing operation of the apparatus.

[0018] For example, each working process comprises, in succession, a feed movement by means of the feed drive and an advancing movement by means of the advancing drive (in particular in this sequence). Optionally, the at least one variation parameter comprises or describes a value (for example an angle, an angular speed, a length or a speed) or a function (for example a speed profile or angular speed profile) of at least a feed movement. Alternatively or in addition, the at least one variation parameter comprises or describes a value (for example an angle, an angular speed, a length or a speed) or a function (for example a speed profile or angular speed profile) of at least an advancing movement.

[0019] In one embodiment, the control data are based on an optimized value of the feed movement and on an optimized speed or an optimized speed profile of the advancing

18905140_1 (GHMatters) P115070.AU movement. Optionally, the control system is designed to calculate the optimized speed of the advancing movement from the product of a predefined speed of the advancing movement with the ratio of a predefined value of the feed movement to the changed value of the feed movement. Thus, in the optimization, the advancing speed is changed in a manner inversely proportional to the value of the feed movement (for example an angle or a length).

[0020] The at least one variation parameter may be or comprise a predefinable maximum conveying rate. This is of interest in particular if it is not imperatively necessary to always maintain the maximum conveying rate that is attainable with the apparatus. For example, if a fixed period of time is available for the loading of a ship, and if said period of time would not be fully exploited in the case of the maximum attainable conveying rate, the conveying rate can be used as variation parameter.

[0021] The control system optionally comprises a user interface for setting at least one variation parameter. For example, the user interface allows a selection of a variation parameter from a multiplicity of parameters. The user interface comprises for example a display device and/or an input means.

[0022] In one embodiment, the control system is designed to provide, over multiple working processes, control data which induce multiple drives of the apparatus (in particular the advancing drive and the feed drive) to perform multiple successive working processes in accordance with a waltz step variation. A waltz step variation comprises multiple working processes, wherein at least one of said working processes has an advancing range reduced in relation to at least one further working process (for example by way of a reduced advancing angle). In this way, residual material is left lying at one or both boundaries of the advancing range. This residual material is then picked up for the first time in a working process with non reduced advancing range. In the case of shallow side slopes, the reduction of the layer height generally cannot be compensated by means of an increase of the advancing speed alone, because the advancing speed in this case often reaches the maximum admissible value. In order to increase the conveying performance in the region of the end of the slope, a reduction of the advancing range is often implemented. This reduction of the advancing range may be performed at both sides (ends) of the advancing range, alternatively or additionally in an alternating sequence of the multiple successive advancing passes (for example pivoting movements). The waltz step variation can, in the case of bucket wheel excavators, also be referred to as interstice formation. The parameters of the advancing control (for example the

18905140_1 (GHMatters) P115070.AU advancing range and/or the sequence of advancing ranges, and the feed parameters) can be adapted to a set stockpile or excavation block geometry, in particular may be fixedly input into programming of the control unit, in order to attain the best possible efficiency (in particular the maximum conveying rate).

[0023] In one refinement, the variation parameter is a value varied in accordance with the waltz step variation, for example the advancing range. Particularly efficient control can be attained in this way.

[0024] Optionally, the control system is designed to ascertain the entire energy efficiency of multiple, in particular successive, working processes (of one, multiple or all drives of the apparatus). The efficiency of a group of working processes can thus be ascertained.

[0025] According to another aspect of the invention, an apparatus for continuously conveying material is provided. The apparatus comprises a working element which is designed for picking up material and which is movable in successive working processes relative to an underlying surface, on which the apparatus is arranged, by at least one drive. The apparatus furthermore comprises a control system according to any configuration described herein above.

[0026] The apparatus is optionally designed as a bucket wheel machine, for example as a bucket wheel excavator or as a bucket wheel reclaimer.

[0027] According to another aspect of the invention, a method for controlling an apparatus for continuously conveying material, having a working element which is designed for picking up material and which is movable in successive working processes relative to an underlying surface by at least one drive, is provided. To perform the method, use may be made in particular of a control system according to any configuration described herein. The method comprises the step of detecting at least one value of a power consumed by at least one drive of the apparatus during a working process; and the step of ascertaining an energy efficiency for the working process on the basis of the at least one value of the consumed power.

[0028] According to yet another aspect of the invention, a computer program product is provided, comprising program code which, when executed on a computer apparatus, induces the computer apparatus to perform the method described above.

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[0029] Further features and advantages will become clear to a person skilled in the art in studying the following detailed description and viewing the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The parts shown in the figures are not necessarily true to scale; rather, the emphasis lies in illustrating principles of the invention. Furthermore, in the figures, the same reference designations are used to denote parts which correspond to one another. In the figures:

[0031] figure 1 shows, schematically and by way of example, a view of an apparatus for continuously conveying material in the form of a bucket wheel reclaimer during the excavation of an upper layer of a stockpile;

[0032] figure 2 shows, schematically and by way of example, a plan view from above of the apparatus and the stockpile as per figure 1;

[0033] figure 3 shows, schematically and by way of example, a feed range of the apparatus as per figure 1 in a plan view from above;

[0034] figure 4 shows, schematically and by way of example, a cross-sectional view of a working element of the apparatus as per figure 1 and of a cutting of material to be excavated;

[0035] figures 5A to 5F show, schematically and by way of example, the cross section of a cutting of material to be excavated at various points in the advancing range as per figure 3;

[0036] figure 6 shows an exemplary diagram of the cutting geometry over the advancing range as per figure 3;

[0037] figure 7 shows an exemplary diagram illustrating a working process of the apparatus as per figure 1;

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[0038] figure 8 shows an exemplary diagram with four successive working processes in accordance with a waltz step variation;

[0039] figure 9 shows an exemplary diagram of a complete excavation of a layer of the stockpile as per figure 2 with a multiplicity of working processes in accordance with a waltz step variation;

[0040] figure 10 shows, schematically and by way of example, a control system of the apparatus as per figure 1; and

[0041] figure 11 shows a method for controlling an apparatus for continuously conveying material.

DETAILED DESCRIPTION

[0042] In the following detailed description, reference is made to the accompanying drawings, in which, through the illustration of specific embodiments, it is shown how the invention can be implemented in practice.

[0043] In this context, direction-indicating terminology such as for example "up", "down", "outward", "inward" etc. may be used with regard to the orientation of the figures being described. Since parts of embodiments may be positioned in a series of different orientations, the direction-indicating terminology may be used for the purposes of illustration and is in no way limiting. It is pointed out that other embodiments can be applied, and structural or logical modifications made, without departing from the scope of protection of the present invention. The following detailed description is therefore not to be understood in a limiting sense, and the scope of protection of the present invention is defined by the appended claims.

[0044] Reference will now be made in detail to various embodiments and to one or more examples illustrated in the figures. Each example is presented in an explanatory manner and is not to be interpreted as a limitation of the invention. For example, features which are illustrated or described as part of an embodiment can be applied to or in conjunction with other embodiments in order to create a yet further embodiment. The fact that the present invention encompasses such modifications and variations is intentional. The examples will be described using a specific language which is not to be interpreted as limiting the scope of protection of

18905140_1 (GHMatters) P115070.AU the appended claims. The drawings are not a true-to-scale representation and serve merely for illustrative purposes. For ease of understanding, the same elements have been denoted by the same reference designations in the various drawings, unless stated otherwise.

[0045] Figure 1 shows an apparatus for continuously conveying material in the form of a bucket wheel reclaimer 1 at a stockpile 3. The bucket wheel reclaimer 1 comprises a superstructure 10 which is mounted, so as to be pivotable about a vertical axis Z, on a substructure 11.

[0046] The superstructure 10 comprises a boom 100 which is held by means of multiple supports 102 and tension cables 103. A working element is mounted at that end of the boom 100 which is averted from the vertical axis Z. In the present example, the working element is a bucket wheel 101.

[0047] The bucket wheel 101 is rotatable about an axis of rotation D (see figure 4) relative to the boom 100 by means of a working element drive in the form of a bucket wheel drive 12. The axis of rotation D is oriented perpendicular to the vertical axis Z. The bucket wheel reclaimer 1 furthermore comprises an advancing drive 13, which is designed to pivot the boom 100 with the bucket wheel 101 about the vertical axis Z relative to the substructure 11 and relative to an underlying surface U. An advancing movement is thus a pivoting movement in the example shown. If the rotating bucket wheel 101 is pivoted along the stockpile 3 by the advancing drive 13, said bucket wheel can pick up material M of the stockpile 3. Owing to the pivoting movement, the bucket wheel 101 cuts into an adjacent slope of the stockpile 3 in an arc-shaped manner. The angle range through which the bucket wheel 101 is pivoted here can also be referred to as advancing range. The material M that is picked up here is transported away by means of a conveyor belt 17. The conveyor belt 17 is driven by means of a conveyor belt drive 15.

[0048] After the bucket wheel 101 has picked up the material M in its excavating range provided by the advancing drive 13, the bucket wheel reclaimer 1 is displaced along a feed axis X (see figure 2). For this purpose, the bucket wheel reclaimer 1 comprises an undercarriage 110, for example in the form of a tracked undercarriage, a rail undercarriage or the like. For a feed movement (in this case in the form of a translation) along the feed axis X, the bucket wheel reclaimer 101 comprises a feed drive 14. In order to be able to pick up new material M in a further advancing movement, the bucket wheel reclaimer 101 is displaced by

18905140_1 (GHMatters) P115070.AU a feed value between two advancing movements. Since, in the example shown, the feed movement is a rectilinear movement, the feed value is a length. An advancing movement and a feed movement together form (in any desired sequence) a working process. Two successive working processes have a reversed advancing direction.

[0049] The bucket wheel reclaimer 1 furthermore comprises a sensor device 16 with at least one, in this case multiple, sensors. The sensor device 16 is designed to continuously detect measurement data in real time. The measurement data indicate for example a local geometry of the stockpile 3 and/or environmental conditions. For example, rain can result in the material M having an increased specific weight.

[0050] The bucket wheel reclaimer 1 has a control system 2. The control system 2 is operatively connected to the sensor device 16 and receives sensor data from the sensor device 16. The control system 2 is operatively connected to the drives (that is to say to the bucket wheel drive 12, to the advancing drive 13, to the feed drive 14 and to the conveyor belt drive and optionally to further drives of the bucket wheel reclaimer 1). The sensor system 2 is designed to control the drives of the bucket wheel reclaimer 1.

[0051] Figure 2 shows a plan view from above of the bucket wheel reclaimer 1 and the stockpile 3. In order to remove a top level of the stockpile 3, the bucket wheel reclaimer 1 performs a multiplicity of working processes. For example, the bucket wheel reclaimer 1 begins at the right-hand edge of figure 2. Where the radius RSC/BW is plotted proceeding from the right hand edge of figure 2, the bucket wheel 101 begins to come into contact with material M of the stockpile 3 as a result of an advancing movement. Here, the bucket wheel 101 cuts laterally into the rising slope of the stockpile 3. That range of the position of the bucket wheel reclaimer 1 along the feed axis X in which the advancing range is limited by the laterally downward slope in relation to a middle part with the length LMPR along the feed axis X can be referred to as "cut in" range. The length Li of the cut-in range along the feed axis X is illustrated in figure 2. Correspondingly, the opposite side of the middle part is adjoined by a "cut-out" range with a length Lo along the feed axis X. In the middle part, the pivot angle P of the advancing range is limited by a left-hand maximum pivot angle(PLmax and a right-hand maximum pivot angle (PRmax (see figure 3). The maximum pivot angles (PLmax, (PRmax are dependent on the length of the boom 100 and on the depth of the stockpile 3 (perpendicular to the feed axis X and to the vertical axis Z). This depth may vary depending on a height setting (by means of a height adjustment device 18) of the bucket wheel 101, as can be seen in particular from figure 1.

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[0052] The radius RSC/BWcorrespondsto the radius from the pivot axis (vertical axis Z) to the axis of rotation D of the bucket wheel 101 (see figures 3 and 4). The radius Rws plotted in figure 2 at the start of the middle part and at the end of the cut-out region corresponds to the radius from the pivot axis (vertical axis Z) to the point of intersection of the straight elongation of the rear side of a bucket wheel cutting 30 with the horizontal surface of the stockpile 3 below the bucket wheel 101, as illustrated in particular in figure 4. Figure 4 furthermore shows the radius Rsc, which corresponds to the radius from the pivot axis to the center of gravity 31 of the bucket wheel cutting 30.

[0053] In order to attain as high as possible a conveying rate of material M picked up per unit of time, the feed value is dimensioned such that the bucket wheel 101 is provided with a bucket wheel cutting 30 with a sufficiently large cross-sectional area As, see in particular figure 4. The cross-sectional area As is dependent on the pivot angle P, on the radius of the bucket wheel 101 and on the slope angles pSB and3IB in relation to a horizontal adjoining the underside of the bucket wheel 101. The conveying rate is furthermore also dependent on the advancing speed, that is to say in the present example on the pivoting speed. The advancing speed is adjustable up to a maximum advancing speed by means of the advancing drive 13.

[0054] Figures 5A to 5C and figures 5D to 5F show the slope of the stockpile 3 and the respective bucket wheel cutting 30 and the center of gravity 31 thereof in various stages during the advancement at the outer boundary (spaced apart from the feed axis X) and at the inner boundary (adjacent to the feed axis X), respectively, of the excavation block.

[0055] Figure 6 shows the dependency, which can be seen from figures 5A to 5F, of the cross-sectional area As of the bucket wheel cutting 30 and the radius Rsc on the pivot angle p. Here, OB denotes the range at the outer boundary and IB denotes the range at the inner boundary of the excavation block. In order, for a substantially constant conveying rate, to compensate for the variable cross-sectional area As, the advancing speed is set in a manner inversely proportional to the cross-sectional area As.

[0056] Figure 7 shows one complete working process with an advancing movement and a subsequent feed movement. The time is plotted on the abscissa, and the cross-sectional area As, the advancing speed Vbwand the feed speed VT, and also the conveying rate Q, are plotted on the ordinate. In the example shown here, the advancing movement begins in the outer

18905140_1 (GHMatters) P115070.AU boundary range and ends in the inner boundary range, such that the profile of the cross sectional area As is similar to that according to figure 6. Since the cross-sectional As is relatively small in the outer boundary range, a high advancing speed Vb" is set here. In the initial seconds, this however reaches a maximum value, such that the conveying rate Q lies below a target conveying rate (of in this case close to 9000 m2 /h). In the middle part, the advancing speed Vbw is set such that, together with the respective cross-sectional area As, the target conveying rate is attained. In the inner boundary range, too, the intensely decreasing cross-sectional area As is compensated by means of a correspondingly intense increase of the advancing speed Vbw. After the completion of the advancing movement, a feed movement is performed. The target conveying rate corresponds for example to the maximum conveying rate, which is limited for example by the capacity of the conveyor belt 17, of the bucket wheel 101 or of another part of the bucket wheel reclaimer 1 or by an apparatus which is supplied with material M by the bucket wheel reclaimer 1.

[0057] Owing to the boundary ranges, the target conveying rate is not attained at the corresponding points in time. In order to increase the average conveying rate, the bucket wheel reclaimer 1 can be controlled in accordance with a so-called waltz step variation.

[0058] Figure 8 shows four successive working processes in accordance with a waltz step variation. Here, in particular in the middle part of the excavation block, it is not the case that the entire advancing range is covered in every working process, it rather being the case that, in some working processes, only a reduced advancing range is covered, such that material M is left lying at one or both boundaries. In a subsequent working process with an advancing range which is not reduced at such a boundary, the bucket wheel 101 can then correspondingly pick up more material M.

[0059] Figure 9 shows the pivot angle p and the duration tA of a working process over a multiplicity of N working processes, with which an entire layer of the stockpile 3 is removed. It is possible to clearly see the cut-in range Cl, the middle part MP and the cut-out range CO. In the middle part, the bucket wheel reclaimer 1 is controlled in accordance with a waltz step variation, which in this case leads to a regular variation of the duration of the working processes and of the maximum pivot angle p.

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[0060] The control system 2 or a control unit operatively connected to the control system 2 is designed to perform the corresponding control. A computer program product may comprise corresponding program code.

[0061] Since the actual geometry of the stockpile 3 may deviate from a predefined (for example calculated or simulated) geometry, the sensor device 16 continuously ascertains the actual geometry. The control system 2 (and/or the optional control unit) correspondingly adapts the size of the advancing range of each working process in a closed-loop control process.

[0062] Depending on how the feed value is set, the control system 2 or the control unit operatively connected to the control system 2 sets the feed speed such that the target conveying rate is attained.

[0063] Figure 10 shows the control system 2 of the bucket wheel reclaimer 1. The control system 2 comprises multiple inputs 20 and multiple outputs 21. At the inputs 20, the control system 2 is connected to the further control unit or to one or more of the drives 12 to 15 of the bucket wheel reclaimer 1, specifically such that said control system can detect at least one value of a power (in particular electrical power) consumed by at least one of the drives 12-15 of the bucket wheel reclaimer 1 during a working process. The control system 2 can detect values of the power consumed by several, in particular all, of the drives 12-15 during a working process. The value or the values may indicate the total power consumed during the complete working process. The control system 2 is configured to receive, via the inputs 20, sensor data which indicate a feed position, an advancing speed and/or a conveying performance (in particular a conveyed material volume and/or a conveyed material mass). Alternatively or in addition, the control system 2 may be configured to receive, via the inputs 20, sensor data which indicate a present slope contour (for example from at least one radar, ultrasound or laser sensor) and/or environmental data.

[0064] The control system 2 comprises a processing unit 24 which receives the value or the values of the consumed power. The control system 2 furthermore receives an indication regarding the material quantity, for example the material volume and/or the material weight, conveyed in the period of time in which the consumed power was consumed. The indication indicates for example the material volume and/or the material weight that was picked up by the bucket wheel 101 (generally the working element) in the corresponding working process. The material M may be weighed and/or measured. Alternatively or in addition, the weight and/or

18905140_1 (GHMatters) P115070.AU the volume may be estimated. The bucket wheel reclaimer 1, in particular the control system 2, may comprise one or more corresponding sensors, which may for example be arranged at the conveyor belt.

[0065] On the basis of the value or the values of the consumed power and the indication regarding the conveyed material quantity, the control system 2 ascertains an energy efficiency for the working process. For this purpose, the control system calculates (by means of the processing unit 24) an energy efficiency coefficient as the at least one value of the consumed power divided by the total volume or the total mass of the material M picked up during the working process. The energy efficiency coefficient is optionally ascertained separately for each advancing direction (pivoting to the left, pivoting to the right) and/or each layer of the stockpile 3. It is possible for a sequence of energy efficiency coefficients to be ascertained for a part or the entirety of the excavation block.

[0066] The control system 2 comprises a user interface 22 with a display device 220. The ascertained energy efficiency, in particular the calculated energy efficiency coefficient, is displayed by the control system 2 by means of the display device 220. A user can read from this information how energy-efficient the settings selected in the associated working process were, and can optionally correspondingly manually adapt settings.

[0067] The user interface 22 furthermore comprises an input means 221. It may optionally be provided that, by means of the input means 221, a user can implement or adapt settings (for example the feed value, the advancing range and/or a target conveying rate), which the control system 2 then sets for a present and/or one or more subsequent working processes. To implement settings, the control system 2 is connected via the outputs 21 to the further control unit and/or to one or more of the drives 12-15. Via the outputs 21, the control system 2 then outputs, for example, corresponding control data.

[0068] In this way, it is possible, with a substantially unchanged conveying rate, to improve the energy efficiency of the bucket wheel reclaimer 1.

[0069] The user interface 22 may for example comprise a screen as display device 220, and, as input means 221, the screen may be touch-sensitive, or alternatively or in addition a keypad or the like may be provided. Furthermore, it is also possible to provide the user interface 22 by way of a web application, for example in the form of a website.

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[0070] Furthermore, the control system 2 comprises a memory 25 for storing computer readable data. In the memory 25, there is stored an optional optimization module 26. Multiple variation parameters 27 are stored in the memory 25. The memory 25 allows ongoing storage and analysis of values. The memory 25 may be fixedly installed or removable. The memory 25 is a computer program product.

[0071] The control system 2 implements the optimization module 26 by means of the processing unit 24. The optimization module 26 receives at least one variation parameter 27, for example the feed value. In the example shown here, the feed value is a length, for example a length between 0.1 m and 1 m. In general, the feed value may alternatively be, for example, an angle. The control system 2 varies the variation parameter 27 over multiple working processes. The optimization module 26 ascertains that value of the at least one variation parameter with which the best energy efficiency has been ascertained, in particular with which the energy efficiency coefficient is minimized, as optimized variation parameter. The optimization module 26 may evaluate the variation parameter after every cycle and/or optimize said variation parameter iteratively over multiple working processes. The optimization module 26 optionally optimizes multiple variation parameters, for example in succession.

[0072] For a present and/or one or more subsequent working processes, the control system 2 then implements settings in accordance with the optimized variation parameter, for example by virtue of said control system 2 outputting corresponding control data via the outputs 21. Optionally, the optimization module 26 optimizes a variation parameter, for example the feed value, and sets another parameter in a proportional or inversely proportional manner. For example, the optimization module 26 (generally the control system 2) changes an advancing speed in a manner inversely proportional to the change in the feed value. In this way, the conveying rate is maintained.

[0073] It is thus possible to achieve energy-efficient reclaiming (or, in the case of an excavator, excavation) of heaped or naturally occurring material M while maintaining the required conveying performance.

[0074] Optionally, the feed values are optimized for each associated advancing direction and in each case from working process to working process.

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[0075] In one optional configuration, the optimization module 26 optimizes a maximum conveying rate, in particular the target conveying rate, as variation parameter. In some cases, an order is not time-critical, for example if a ship is to be loaded with a predefined material volume or weight by means of the bucket wheel reclaimer 1, and more time is available for this than is required with the maximum settable conveying rate. It is then possible for the target conveying rate to be optimized as variation parameter as an alternative or in addition to other variation parameters.

[0076] A variation parameter may in particular be at least one value varied in accordance with the waltz step variation, for example at least one limit of the advancing range and/or the alternating pivoting reduction from the left/right, and/or the overlap time for the feed movements with the one or more advancing movements.

[0077] Optionally, between two energy efficiency optimizing processes, the average conveying performance is increased for both advancing directions or for multiple coherent advancing movements (for example four pivoting movements of the waltz step variation) by means of a conveying-performance-increasing optimization. For this purpose, advancing range reduction values (for example the pivot angle reduction values from both sides of the pivot range and the waltz step variation) may be changed such that the conveying performance efficiency is improved, in particular maximized, while maintaining the feed values and the maximum admissible conveying rate.

[0078] Optionally, using the input means 221, it is possible to set which settable parameter is to be optimized as variation parameter.

[0079] The control system 2 may be the central control system of the bucket wheel reclaimer 1. Alternatively, said control system is an additional control system 2 which is operatively connected to one or more other control units of the bucket wheel reclaimer 1. Optionally, the control system 2 can be retrofitted on an existing bucket wheel reclaimer. Optionally, the control system 2 may, by means of analog interfaces and/or a field bus system, be placed in communicative connection with an existing machine controller and/or with sensors (and/or other control elements, for example at least one frequency converter), for example via a conventional industrial communication interface.

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[0080] The individual components of the control system 2 shown in figure 10 may be installed on or in a common housing. Alternatively, some or all components may be arranged at different locations (for example at different points of the bucket wheel reclaimer 1) and operatively connected to one another.

[0081] Figure 11 shows a method for controlling an apparatus for continuously conveying material.

[0082] To start, an apparatus for continuously conveying material, for example the bucket wheel reclaimer 1 described above, is provided.

[0083] In step S1, by means of the apparatus, at least one working process is performed, which comprises in particular a feed movement and an advancing movement.

[0084] In step S2, at least one value of an (in particular electrical) power consumed by at least one drive of the apparatus during the working process is detected, for example by means of the above-described control system 2. For example, the integral of all drive powers consumed by all drives of the apparatus over one full working process is ascertained.

[0085] In step S3, an energy efficiency for the working process is ascertained on the basis of the at least one detected value of the consumed power. For example, for this purpose, the described energy efficiency coefficient is calculated.

[0086] In step S4, in a manner dependent on the ascertained energy efficiency, control data for one or more subsequent working processes are provided (for example by means of the control system 2), in particular to the apparatus.

[0087] The steps S1 to S4 are optionally performed in a loop. One possible termination criterion is the complete removal of the layer of the stockpile.

[0088] Through the adaptive, energy-efficient closed-loop control, it is thus possible, for the continuously conveying apparatus, to provide a control method with gradual change of the feed value (for example forward travel) and/or of an advancing parameter (for example of the pivot angle range with a pivot angle reduction) in a defined sequence. This allows a gradual

18905140_1 (GHMatters) P115070.AU approximation of the specific energy requirement (in relation to the conveyed material volume) to a minimum possible value whilst maintaining predefined conveying performance.

[0089] The apparatus for continuously conveying material has been described by way of example above as a bucket wheel reclaimer 1. The statements made above self-evidently correspondingly also apply to other continuously operating loaders, for example to bucket wheel excavators.

[0090] The above-described control system 2, the bucket wheel reclaimer 2 equipped therewith and the method make possible, and provide, in particular one or more of the following operating modes.

[0091] The entire expenditure of energy for the picking-up of material, conveyance of material and setting-down of material for a defined conveying rate (for example layer volume, block or stockpile volume) can be minimized.

[0092] A minimization of energy (and minimization of cost) for the reclaiming or the excavation of a predefined quantity of heaped or naturally occurring material M, whilst specifying an admissible reduction in conveying performance or a maximum conveying time for said quantity, is possible.

[0093] Furthermore, an automatic adaptation of the advancing ranges to the changing stockpile or block geometry, with the aim of maintaining the conveying performance efficiency and/or energy efficiency, is possible.

[0094] Where used here, the expressions "comprising", "having", "including" and the like are open expressions which indicate the presence of stated elements or features but do not rule out additional elements orfeatures. It is pointed outthatthe present invention is not limited by the above description, and is also not limited by the accompanying drawings. The present invention is rather limited only by the following claims and the legal equivalents thereof.

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LIST OF REFERENCE DESIGNATIONS

1 Bucket wheel reclaimer (apparatus for continuously conveying material) Superstructure 100 Boom 101 Bucket wheel (working element) 102 Support 103 Tension cable 11 Substructure 110 Undercarriage 12 Bucket wheel drive (working element drive) 13 Advancing drive 14 Feed drive Conveyor belt drive 16 Sensor device 17 Conveyor belt 18 Height adjustment device 2 Control system Input 21 Output 22 User interface 220 Display device 221 Input means 24 Processing unit Memory 26 Optimization module 27 Variation parameters 3 Stockpile Bucket wheel cutting 31 Center of gravity D Axis of rotation M Material N Number of working processes U Underlying surface

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X Feed axis Z Vertical axis (p Pivot angle

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Claims

1. A control system of an apparatus for continuous reclaiming and/or extracting and subsequent conveying of material from a stockpile or a solid mass of such material, such as a bucket wheel excavator or reclaimer, the apparatus having a working element configured for continuously picking up said material and which is movable in successive working processes relative to an underlying surface by at least one drive, each of said working processes comprising a combination of alternating feed and advance movements of the working element and whilst the working element moves continuously in the process of picking up said material, wherein the control system is configured to: - detect at least one value of power and/or energy consumed by the at least one drive of the apparatus during one of the working processes, wherein the at least one drive includes separate feed and advance drives for performing said feed and advance movement of the working element; - ascertain an energy efficiency for the one working process on the basis of the at least one value of power and/or energy consumed, by calculating a ratio of the power and/or energy consumed by the feed and advance drives within the one working process to a feed value of the one working process; and - in a manner dependent on the energy efficiency ascertained for the one working process, provide control data relating to a working process subsequent to the one working process, to operate the apparatus in the subsequent working process with apparatus operating parameter values which result in an improved energy efficiency with respect to that ascertained for the one working process.

2. The control system as claimed in claim 1, wherein the apparatus further comprises a separate working element drive, and wherein the control system is configured to: - calculate a ratio of the entire energy consumed by the working element, feed and advance drives within the relevant working process to the feed value of that working process, for the ascertainment of the energy efficiency.

3. The control system as claimed in claim 1 or 2, further configured to receive sensor data and calculate the control data in a manner using the sensor data.

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4. The control system as claimed in claim 2 or 3, further configured to determine an energy efficiency coefficient as the value of the entire energy consumed by the working element, feed and advance drives within one of the working processes divided by a total volume or mass of the material picked up during that working process, for the ascertainment of the energy efficiency.

5. The control system as claimed in claim 4, wherein the apparatus further comprises a conveyor arranged for removing the material picked-up by the working element, and wherein the control system is further configured to use the drive power consumed by the advance drive, the feed drive, the working element drive and a drive of the conveyor belt, for the determination of the energy efficiency coefficient.

6. The control system as claimed in anyone of the preceding claims, further configured to, through variation of at least one variation parameter over several of said working processes, obtain at least one optimized variation parameter, by means of which the energy efficiency is increased in relation to other values of the variation parameter.

7. The control system as claimed in claim 6, wherein each of the working processes comprises, in succession, a feed movement of the working element by the feed drive and an advance movement of the working element by the advance drive, and wherein the at least one variation parameter comprises a value of at least one feed movement and/or a value of at least one advance movement.

8. The control system as claimed in claim 7, wherein the control data are based on an optimized value of the feed movement and on an optimized speed of the advance movement, and wherein the control system is further configured to calculate an optimized speed of the advance movement from the product of a predefined speed of the advance movement with the ratio of a predefined value of the feed movement to the optimized value of the feed movement.

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9. The control system as claimed in anyone of claims 6 to 8, wherein the at least one variation parameter comprises a maximum material conveying rate.

10. The control system as claimed in anyone of claims 6 to 9, furthermore comprising a user interface for setting the at least one variation parameter.

11. The control system as claimed in anyone of claims 2 to 10, further configured to provide the control data configured for inducing the multiple drives of the apparatus to perform multiple working processes in accordance with a waltz step variation.

12. The control system as claimed in claim 11, when dependent on claim 6, wherein the variation parameter is a value varied in accordance with the waltz step variation.

13. The control system as claimed in anyone of the preceding claims, further configured to ascertain an entire energy efficiency based on all of the working processes.

14. An apparatus for continuous reclaiming and/or extracting and subsequent conveying of material from a stockpile or a solid mass of such material, comprising a working element configured for continuously picking up said material and which is movable in successive working processes relative to an underlying surface by at least one drive, each of said working processes comprising a combination of alternating feed and advance movements of the working element and whilst the working element moves continuously in the process of picking up said material, the at least one drive comprising separate feed and advance drives for performing the alternating feed and advance movements of the working element, and optionally a separate working element drive and a conveyor drive for a conveyor arranged for receiving the material picked-up and deposited by the working element onto the conveyor, and further comprising a control system as claimed in any of the preceding claims.

15. The apparatus as claimed in claim 14, wherein the apparatus is a bucket wheel excavator or a bucket wheel reclaimer.

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16. A method for controlling an apparatus according to claim 14 or 15, the method comprising: - detecting at least one value of power and/or energy consumed by the at least one drive of the apparatus during one of the working processes; - ascertaining an energy efficiency for the one working process on the basis of the at least one value of power and/or energy consumed, by calculating a ratio of the power and/or energy consumed by the feed and advance drives within the one working process to a feed value of the one working process; and - in a manner dependent on the energy efficiency ascertained for the one working process, provide control data relating to a working process subsequent to the one working process, to operate the apparatus in the subsequent working process with apparatus operating parameter values which result in an improved energy efficiency with respect to that ascertained for the one working process.

17. A computer program product comprising a non-volatile memory with program code which, when executed on a computer apparatus, causes the computer apparatus to perform the method as claimed in claim 16.

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