AU634802B2

AU634802B2 - Conveying-quantity control of a bucket-wheel excavator or bucket-wheel pick-up in open-cast mining

Info

Publication number: AU634802B2
Application number: AU60278/90A
Authority: AU
Inventors: Ralf Eckoldt; Franz-Arno Fassbaender; Franz-Josef Hartlief; Edmund Heimes; Dieter Henning; Johann Hipp; Hans-Jeorg Neusslin
Original assignee: Siemens AG
Current assignee: SICK IBEO GmbH; Siemens AG
Priority date: 1989-08-08
Filing date: 1990-08-07
Publication date: 1993-03-04
Anticipated expiration: 2010-08-07
Also published as: EP0412399A1; AU6027890A; ATE99758T1; EP0412399B1; DE59004104D1; ES2048372T3

Abstract

The invention relates to an extracted-quantity control system for a bucket wheel excavator (6), in which the slewing speed of the bucket wheel boom (7) and/or its vertical position is controlled while taking into account the bucket-wheel drive current as well as the weight and volume of the extracted material, the extracted volume of solid material cut by the bucket wheel being used as a further control variable. <IMAGE>

Description

634802 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION S F Ref: 137509

(ORIGINAL)

FOR OFFICE USE: Class Int Class 9.

r Complete Specification Lodged: Accepted: Published: Priority: Related Art: Name and Address of Applicant: Siemens Aktiengesellschaft Wittelsbacherplatz 2 D-8000 Munich 2 FEDERAL REPUBLIC OF GERMANY

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Rheinbraun Aktiengesellschaft Stuttgenweg 2 0-5000 Koln 41 (Lindenthal) FEDERAL REPUBLIC OF GERMANY IBEO-Ingenieurburo fur Elektronik und Optik J, Hipp G. Broehan Fahrenkroen 121 D-2000 Hamburg 71 FEDERAL REPUBLIC OF GERMANY Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia 41. A Address for Service: Complete Specification for the invention entitled: Conveying-Quantity Control of a Bucket-Wheel Excavator or Bucket-Wheel Pick-Up in Open-Cast Mining The following statement is a full description of this invention, including the best method of performing it known to me/us 5845/3 1 Abstract Conveying-quantity control of a bucket-wheel excavator or bucket-wheel pick-up in open-cast mining The invention relates to a conveying-quantity control of a bucket-wheel pick-up in open-cast mining, in which the pivoting speed of the bucket-wheel jib and/or its height are controlled according to the bucket-wheel drive current and the weight and volume of the conveyed material, the solid-material conveying volume cut by the bucket wheel being used as a further control variable.

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GR 89 P 8568 E/Foreign Siemens Aktiengesellschaft RHEINBRAUN Rheinische Braunkohlenwerke Aktiengesellschaft IBEO Ingenieurbiro fur Elektronik und Optik Conveying-quantity control of a bucket-wheel excavator or bucket-wheel pick-up in open-cast mining The invention relates to the conveying-quantity control of a bucket-wheel excavator or bucket-wheel pick-up in open-cast mining, in which the pivoting speed of the bucket-wheel jib and/or its height are controlled according to the bucket-wheel drive current and the weight and volume of the conveyed material.

For operatihg a bucket-wheel excavator, it is essential to control the lifting and/or pivoting movement of the bucket-wheel jib in such a way that the largest possible 15 conveying volume is obtained, without overloading the os bucket-wheel drive and the belts conveying away. To control a bucket-wheel excavator or bucket-wheel pick-up, se..

it is known to measure the bucket-wheel drive current and the weight and volume of the conveyed material and to control accordingly the pivoting movement and possibly the lifting height of the bucket wheel. By means of these control variables, the conveyance of a bucket-wheel excavator or b cket-wheel pick-up is already satisfactory, but a control at the extreme performance limit of the bucket-wheel excavator or bucket-wheel pick-up is not yet possible, because the weight and volume of the conveyed material can be determined only with an interval

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of time after the actual conveying operation and only inexactly.

A direct measurement of the cut volume on the bucket wheel has hitherto not been known and does not even seem possible with the current technical means. Methods of inferring the volume-of the sliver instantaneously cut by SHo/Th-13.07.1990 -2the bucket-wheel indirectly from a measurement of geometrical parameters of the excavator have been known hitherto. The calculation includes, among other things, the sliver advance which is executed by the excavator after each pivoting operation and which is used as a measure of the thickness of the sliver. The further travel of the excavator is measured, for example, by means of path-measuring sensors on the excavator running gear. However, this measured value often involves considerable errors caused by mechanical inaccuracies and problems with dirt. A back inference from the conveyed volume to the volume to be cut is possible only to a limited extent because of the varying loosening factor.

The known measuring methods produce an appreciable measuring'error, and therefore they do not allow a control of the excavator in the 1 boundary region between overloading and the largest possible conveying quan'tity. A control according to the current consumption of the bucket-wheel drive is also incapable of this, especially because this involves the varying material-dependent conditions of friction on the bucket wheel.

The object of the invention is to provide a conveying-quantity control which allows a reliable command of the mining operation at the limit of a predetermined conveying capacity which corresponds to the maximum permissible conveying capacity of the conveying appliance or of downstream conveying installations.

The object is achieved in that the solid-material conveying volume 25 detected by the bucket wheel is used as a further control variable.

In accordance with the present invention there is disclosed conveying-quantity control of a bucket-wheel excavator or a bucket-wheel pick-up in open-cast mining, in which the pivoting speed of a bucket-wheel jib and/or its height are controlled according to a solid-material conveying volume cut by the bucket wheel, said excavator or pick-up comprising a radiation transmitter/receiver arranged in the vicinity of the bucket wheel, said transmitter/receiver sensing the contour of the solid material in the pivoting direction in front of the bucket wheel, and wherein said radiation transmitter/receiver is a laser scanner which measures the contour of the solid material to be dealt with 7740 2A via transit-time measurements of a pulsed beam of laser light which are evaluated in a computer".

The solid-material conveying volume detected by the bucket wheel allows a direct conclusion regarding the load on the excavator and its degree of utilization. The bucket-wheel excavator or the bucket-wheel pick-up can therefore advantageously be controlled in such a way that it picks up the instantaneously predetermined conveying quantity. This can be 9 9

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3 obtained as a result of a variation in the pivoting speed of the bucket-wheel jib arm alone or in conjunction with the variation- in the lifting height. To achieve the object, it is envisaged that the solid-material conveying volume detected by the bucket wheel is determined by means of a laser beam which senses the contour of the solid material in the pivoting direction in front of the bucket-wheel. The sensing of the contour of the solid material in the pivoting direction in front of the bucket wheel by a laser beam, which works preferably at a wavelength of 905 nanometers, a pulse rate of 3.6 kHz and a pulse duration of approximately 10 nanoseconds, allows an especially accurate determination of the cut volume to be removed which is insensitive to different temperatures, dust swirled up and further environmental influences. There is therefore an operationally reliable measurement of the cut volume to be removed which allows a reliable control of the conveying quantity of the bucket-wheel excavator or the bucket-wheel pick-up.

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Furthermore, in an embodiment of the invention, the laser beam is generated by a positionally oriented measuring laser which is arranged in the vicinity of the bucket wheel and which measures the contour of the solid materii" t al to be dealt with via the transit-time measurements of 25 the pulsed laser light which are evaluated by a computer.

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0* In this application, the advantage of employing a measuring laser, especially in the form of a laser scanner, is that a linear detection of the sector to be cut away takes place. As a result of the scanning line by line or in wavy-line form, not only individual data but the configuration of the working face can be detected. By means of optics of low outlay, a high instantaneous energy density can be obtained via the low-scatter light of a laser scanner, with the result that errors caused by excessive scatter, insufficient reflection, etc. are prevented or reduced. This affords, in general, an especially operationally reliable measuring and control 11 "'Arttt4k-

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4process suitable for open-cast mining.

Further advantages and details of the invention emerge from the description which follows with reference to the drawing and in conjunction with the subclaims. In the drawing: Figure 1 shows a view of the working location, Figure 2 shows a representation of the geometrical relations in a sliver measurement, and Figure 3 shows a representation of the geometrical relations at the working location in simplified form.

0 Figure 1 shows the determination of the details of the working location by two measuring lasers, especially :laser scanners 8, 9, which vertically survey the surface 15 profile on 'the worked material 1 and the cleared surface 3 by scanning along the scan lines 10, 11. The laser fees scanners 8, 9 are mounted on the bucket-wheel carrier 7 next to the bucket wheel 6 with the blades 5 and primarily survey the downward directed profile part 2. The profile is determined from pairs of distance/angle values. The profile 1, 2 on that side towards which the bucket wheel 6 is moving is primarily used for the control. When there is a uniform movement in only one direction and when there is no differential measurement,, the second profile scanner can also be omitted. During the pivoting movement, the bucket wheel 6 rotates and cuts away the solid material 1 by ,the surface amount 4.

As shown in Figure 2, the rear profile 12 (solid material cut away) is predetermined by the contour of the bucket wheel 6, since all the projecting material is necessarily cut away. The cross-sectional area 14 of the particular sliver is calculated from the rear contour 12 and the measured profile 13. The overlap of the bucket wheel 6 over the measured profile of the laser scanner represents this differential area. As a result of the pivoting movement of the excAvator, the bucket wheel 6 cuts 5 laterally into the solid material. The faster this pivoting movement takes place, the larger the volume of the sliver. The volume per unit time covered by the cross-sectional area 14 of the sliver represents the conveyed volume flow of the solid material instantaneously cut away. The necessary calculations for the solid material, conveying volume, sliver thickness, sliver height, position of the cut surface and overmeasure (surveyed separately) are carried out in a computer which follows the laser scanner. This computer can be integrated in the laser scanner. Essentially the pivoting radius, the pivoting speed, the lifting angle of the bucket-wheel jib, the mounting position of the laser scanner 8, 9, further geometrical dimensions of the 15 excavator and its position in space are necessary for the calculation. This information can easily be stored in the computer of the laser scanner. Advantageously, the computer is equipped with a permanent write memory.

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Since the mounting location and alignment of the laser scanner 8, 9 relative to the excavator 16 are known or can be determined once, the lifting angle of the bucket-wheel jib is to be utilized directly in the laser scanner 8, 9 or in the following computer. The length of the bucket-wheel jib is a known parameter. In conjunction 25 with the pivoting speed, the information is sufficient to calculate the solid-material volume flow from the profile data in the laser scanner 8, 9 or in the following computer, without further measured values having to be fed to the laser scanner 8, 9 or following computer. If the excavator i 16 is in an oblique position, it may be necessary to make a correction which pan be determined from a perpendicular measurement and which is fed to the computer as a correcting variable. As shown in Figure 2, for predetermining a cut surface, the three-dimensional profile is to be oriented in space by reference to the perpendicular The profile part on the track level 3 (cleared surface) 6 can be approximated by a straight line. The gradient of this straight line can be calculated. The height of the bucket wheel 6 above the track level can likewise be determined from the profile by calculating the projection onto the vertical from the oblique distance to the approximated straight line of the track level. Actual values for the location of the bucket wheel 6 can be calculated from the two variables. The location of the bucket wheel 6 in relation to the standing point of the excavator 16 can thus be measured continuously. If desired values are preset for the location of the bucket wheel 6, a control variable for commanding the bucket wheel 6 to follow any surface forms can be derived from the difference between the actual values and the desired 15 values.

Since both the position of the bucket-wheel jib 7 and the surface contour of the track level 3 and of the cut surface are known, the distance of the jib 7 from the material to be dealt with can also be calculated. Falling below a specific distance can be utilized highly advantageously to trigger a collision alarm.

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OeO S. S *5 a s a. a 0*046* The foregoing invention, which solves a basic problem 4 hitherto considered insoluble in the work of bucket-wheel g" excavators, can preferably be put into prcactice by means 25 of laser scanners, especially IR laser scanners. It is self-evident to a person skilled in the art, however, that other radiation sources comparable to a laser can also be used, for example electromagnetic emitters of very high frequency and with a comparable beam focusing.

Positions of the measuring lasers other than those indicated in the drawing are also likewise possible. If a large amount of dust is generated, it is recommended, for example, to have a mounting on the excavator and a contour detection of the working face at a distance of to 20 m from the bucket wheel.

Claims

9. o9 9 9 9 9. 9 oo 9 9 90 9 99* 9 9* 9. .9 9 o r o The claims defining the invention are as follows: 1. Conveying-quantity control of a bucket-wheel excavator or a bucket-wheel pick-up in open-cast mining, in which the pivoting speed of a bucket-wheel jib and/or its height are controlled according to a solid-material conveying volume cut by the bucket wheel, said excavator or pick-up comprising a radiation transmitter/receiver arranged in the vicinity of the bucket wheel, said transmitter/receiver sensing the contour of the solid material in the pivoting direction in front of the bucket wheel, and wherein said radiation transmitter/receiver is a laser scanner which measures the contour of the solid material to be dealt with via transit-time measurements of a pulsed beam of laser light which are 'evaluated in a computer. 2. Conveying-quantity control according to claim 1, wherein the laser beam measures the contour of the solid material to be dealt with, next to the bucket wheel, by means of-a continuous measurement of the distance and angle relative to thi/ material surface and feeds these data to the computer, which calculates the profile therefrom. 3. Conveying-quantity control according to claim 1 or 2, wherein the cross-sectional area of the sliver seized by the bucket wheel is calculated from the profile, the geometrical dimensions of the bucket wheel, and the mounting position of the measuring laser. 4. ConveyIng-quantity control according to claim 1, 2 or 3, wherein the volume of the cut solid material is calculated from the difference between the surface profile and the outer contour of the bucket wheel, and from the lifting angle and pivoting speed. Conveying-quantity control according to any one of the preceding claims, wherein the profile is determined on both sides next to the bucket wheel by continuous measurement, and an instantaneous value of the cut solid material is determined from the profile difference and the pivoting speed. 6. Conveying-quantity control according to any one of the preceding claims, wherein the measuring laser and the computer are connected to a permanent write memory, in which parameters relating to the excavator and to the mounting position of the laser scanner 'and adjustment values are stored. ALIq ND/1774o -8- 7, Conveying-quantity control according to any one of the preceding claims, wherein the angular sectors not used for the profile evaluation, the measuring laser measures in relation to a target within the appliance and the known distance thus measured is used as a checking value for the operating capacity of the appliance and as a calibration value. 8. Conveying-quantity control according to any one of the preceding claims, wherein the measuring laser works at pulse durations of 1 to 10 nanoseconds and at a pulse rate in the range 3 kHz 30 kHz. 9. Conveying-quantity control according to any one of the preceding claims, wherein for the pulse transit-time measurement a 'starting pulse is first generated, the reflected fraction of this being lengthened in terms of transit time via delay lines, preferably in coil form, and being used for a start-stop measurement.
10. Conveying-quantity control of a bucket-wheel excavator or a bucket-wheel pick-up in open cast mining substantially as described herein with reference to the drawings. DATED this SIXTEENTH day of DECEMBER 1992 Siemens Aktiengesellschaft Rheinbraun Aktlengesellschaft IBEO-Ingenleurburo fur Elektronik und Optik J. Hipp G. Broehan Patent Attorneys for the Applicants SPRUSON FERGUSON IAD/1774o