AU634801B2

AU634801B2 - Conveying-volume measurement from the cut contour of a bucket-wheel excavator or other open-cast mining appliance

Info

Publication number: AU634801B2
Application number: AU60276/90A
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: EP0412398A1; EP0412398B1; AU6027690A; AU6028190A; ATE111995T1; DE59007214D1; AU637125B2

Abstract

The invention relates to the measurement of the extracted volume from the cutting profile of a bucket wheel excavator (6) or the like by means of pulse transit-time measurements of the geometry of a working face. The geometry of the working face is determined by at least one laser beam via transit-time measurements of the laser light, which laser beam is produced in a positionally orientated measuring laser (8, 9) carried along by the machine, the transit time being analysed in a computer. <IMAGE>

Description

t i" 9 634801 S F Ref: 137499 FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Class Int Class Complete Specification Lodged: Accepted: Published: Priority: Related Art: Name and Address of Applicant: Siemens Aktiengesellschaft Wittelsbacherplatz 2 8000 Muenchen FEDERAL REPUBLIC OF GERMANY 1@

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Rheinbraun Aktiengesellschaft Stuttgenweg 2 D-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 Address for Service: Complete Specification for the invention entitled: Conveying-Volume Measurement From the Cut Contour of a Bucket-Wheel Excavator or Other Open-Cast Mining Appliance The following statement is a full description of this invention, including the best method of performing it known to me/us 5845/3 1 GR 89 P 8567 E/Foreign Abstract Conveying-volume measurement from the cut contour of a bucket-wheel excavator or other open-cast mining appliances The invention relates to conveying-volume measurement from the cut contour of a bucket-wheel excavator or other open-cast mining appliances by means of pulse transit-time measurements of the geometry of a working location. The determination of the geometry of the working location takes place via transit-time measurements of laser light by means of at least one laser beam generated in a positionally oriented measuring laser carried aljong by the open-cast mining appliance, the transit time being evaluated in a computer.

FG ooo FIG. 1 .0 se 1A- GR 89 P 8567 E/Foreign Siemens Aktiengesellschaft RHEINBRAUN Rheinische Braunkohlenwerke Aktiengesellschaft IBEO Ingenieurbiro fur Elektronik und Optik Conveying-volume measurement from the cut contour of a bucket-wheel excavator or other open-cast mining appliance The invention relates to conveying-volume measurement from the cut contour of a bucket-wheel excavator or other open-cast mining appliance by means of the contactlessly measured geometry of a working location.

For operating a bucket-wheel excavator, it is essential to measure the conveyed volume of the material to be removed, so that this can be used, for example, as a command variable for controlling the excavator. It is 15 thus possible to optimize the conveying capacity of the excavator. A further use is, for example, the preparation of the overmeasure for the overriding operating control.

A direct measurement of the conveyed volume of material on the bucket wheel is not known and does not even seem possible with the current technical means.

Methods for inferring the volume of the sliver cut by the bucket wheel indirectly from a measurement of geometrical parameters of the excavator and calculating the conveyed volume from this are, however, known. This calculation 25 includes, among other things, the further travel 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 very often involves considerable errors caused by mechanical inaccuracies and problems with dirt.

In contrast to the measurement of the conveyed solid-material volume, a volume-flow measurement for bulk materials on belt conveyors is known in diverse forms.

SHo Th 13.07.1990 2 GR 89 P 8567 E/Foreign These usually involve measurements with distancemeasuring instruments, by means of which measurements are taken in relation to the surface of the bulk material at one or more points for contour determination. From the difference between the measurements on the empty belt and on the filled belt, the surface area of the bulk material and, from the product of the surface area and the speed of the belt, the volume flow in the loosened form, in which it is present on the belt, can be calculated with high accuracy. Since the conveyed material is transferred from the bucket wheel onto a conveyor belt, the conveyed volume of worked material can be deduced from the volumeflow measurement of the bulk material on the conveyor belt only with the considerable inaccuracy of material- Go. 15 dependent loosening factors.

Measuring instruments of the above-described type, by means of which the conveying volume of the eg g. worked material can be inferred, aee shown, for example, *°ij in DE-Al-3,411,540. Here, points of the contour of the 20 free surface of the conveyed material are sensed transversely relative to the conveying direction by continuous contactless distance measurements by means of transmitting/receiving devices followed by a computer. In this ,*goe. known determination of the filling cross-section, the 25 measurement of the filling height of the conveyor belt is obtained by using as a transmitting/receiving device *o laser distance-measuring instruments which work on the pulse transit-time measurement principle and in which at least two individual lasers transmit their measurement 30 results to a computer for determining the conveying volume on the belt. The measurement result is relatively inaccurate since the measured individual points do not make it possible to make any conclusion regarding the exact course of the surface contour.

The object of the invention is to provide a conveying-volume measurement which directly measures the contours of the material to be removed and variables to be derived therefrom, such as the sliver thickness, sliver height, position of the cut surface at the working 3 GR 89 P 8567 E/Foreign 0

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*5 S 0 location, etc. At the same time, the determination of the sliver volume will be insensitive to different temperatures, to dust swirled up and to the other environmental influences. The results determined will be so accurate that a control of the working operation and the preparation of an overmeasure are possible.

The object is achieved in that the determination of the geometry of the working location takes place via transit times of laser light by means of at least one laser beam generated in a positionally oriented measuring laser carried along by the open-cast mining appliance, the transit times being evaluated in a computer. \dditionally, during the measuring operation the angular position of the measuring beam is transmitted to the 15 computer. At the same time, the positional orientation of the measuring laser can take place either mechanically or virtually in the computer by the use of a sensor.

The control of the bucket-wheel movement can thus be optimized. 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 result of the sensing line by line or in wavy-line form, not only individual data, but the configuration of the working face can be det- 25 ected. The use of a laser, preferably a solid-state laser, which preferably works at a wavelength of 905 nanometers, a pulse rate of 3.6 kHz and a pulse duration of approximately 10 nanoseconds, is especially advantageous for the scanning, because a high energy density is achieved by means of its light of very low divergence and via optics involving a low outlay, with the result that errors caused by an excessive scatter, insufficient reflection, etc., are prevented or reduced.

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 fee* p S 0..0 00..

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55 4 GR 89 P 8567 E/Foreign 0* 0S*@

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5* relations in a sliver measurement, and Figure 3 shows a representation of the geometrical relations at the working location in simplified form.

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 profile on the worked material 1 and the cleared surface 3 by scanning along the scan lines 10, 11. The laser scanners 8, 9 are mounted on the bucket-wheel carrier 7 next to the bucket wheel 6 with the buckets 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 20 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 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

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600 5 GR 89 P 8567 E/Foreign 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 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.

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 i5 with the pivoting speed, the information is sufficient to calculate the solid-material volume, flow from the profile e. data in the laser scanner 8, 9 or in the following computer, without further measured values having to be 4' fed to the laser scanner 8, 9 or following computer. If 20 the excavator 16 is in an oblique position, it may be necessary to make a correction which can 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 :25 profile is to be oriented in space by reference to the perpendicular The profile part on the track level 3 (cleared surface) can be approximated by a straight line. The gradient of this straight line can be calculated. The 30 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

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-6wheel 6 to follow any surface forms can be derived from the difference between the actual values and desired 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.

In the preferred embodiment, the angular sectors not used for the profile evaluation, the measuring laser measures in relation to a target within the bucket-wheel excavator, and the known distance thus measured is used as a checking value for the operating capacity of the bucket-wheel excavator and as a calibration value.

Also preferably, for 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 is used for a start-stop measurement.

Preferably, the measuring laser works at pulse durations of 1-10 nanoseconds and at a pulse rate in the kilohertz range, preferably in the 3-30 kHz range.

The foregoing invention, which solves a basic problem, hitherto r' considered insoluble In the work of bucket-wheel excavators, can preferably be put into practice by means of 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 25 electromagnetic emitters ?f 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 10 to 20 m from the bucket wheel.

IAD/1781o

Claims

1. Conveying-volume measurement from the cut contour of a bucket-wheel excavator or other open-cast mining appliances by means of the contactlessly measured geo- metry of a working location, characterized in that the determination of the geometry of the working location takes place via transit times of laser light by means of at least one laser beam generated in a positionally oriented measuring laser carried along by the open-cast mining appliance, the transit times being evaluated in a computer.

2. Conveying-volume measurement according to Claim 1, characterized in that the laser beam measures the three-dimensional surface profile of the solid material occurring next to the bucket wheel by a continuous measurement of the distance- and angle in relation to the material surface and feeds these profile data to the computer, and in that the cross-sectional area of the sliver cut away by the bucket wheel is calculated in this computer from the profile, the geometrical dimensions of the bucket wheel and the mounting position of the measuring laser. "or"

3. Conveying-volume measurement according to Claim 1 or 2, characterized in that the volume flow of the conveyed solid material is calculated from the difference between the surface profile and the outer contour of the bucket wheel and the lifting angle and rotational speed of the bucket-wheel arm.

4. Conveying-volume measurement according to Claim 1, 2 or 3, characterized in that the geometry of the working location is determined from a measuring position in the region of the bucket wheel.

Conveying-volume measurement according to Claim 1, 2, 3 or 4, characterized in that the profile is determined on both sides next to the bucket wheel by a continuous measurement and an instantaneous value of the conveying volume is determined from the profile differ- ence and the pivoting speed.

6. Conveying-volume measurement according to any one of the preceding claims, characterized in that 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.

7. Conveying-volume measurement according to any one of the preceding claims, characterized in that, in the angular sectors not used for the profile evaluation, the measuring laser measures in relation to a target within the bucket-wheel excavator, and the known distance thus measured is used as a checking value for the operating capacity of the Sbucket-wheel excavator and as a calibration value.

8. Conveying-volume measurement according to any one of the preceding claims, characterized in that 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 is used for a start-stop measurement.

9. Conveying-volume measurement according to any one of the preceding claims, characterized in that the measuring laser works at pulse durations of 1-10 nanoseconds and at a pulse rate in the kilohertz range, preferably in the 3-30 kHz range.

10. Conveying-volume measurement according to any one of the preceding claims, characterized in that for the conveying-volume measurement of an open-cast mining conveying appliance a laser scanner *i carried along by the appliance is used.

11. Conveying-volume measurement according to claim characterized in that the measured conveyed volume of an open-cast mining conveying appliance is used for assessing the open-cast mining operation. i*t

12. Conveying-volume measurement substantially as described herein with reference to the drawings, DATED this TWELFTH day of JANUARY 1993 Siemens Aktinegesellschaft IBEO-Ingenieurburo fur Elektronik und Optik 3. Hipp G. Broehan Rheinbraun Aktiengesellschaft SPatent Attorneys for the Applicants SLSPRUSON FERGUSON