AU635762B2

AU635762B2 - Guidance of an excavator bucket wheel for generating predetermined surfaces

Info

Publication number: AU635762B2
Application number: AU60279/90A
Authority: AU
Inventors: Ralf Eckoldt; Franz-Arno Fassbaender; Franz-Josef Hartlief; Edmund Heimes; Dieter Henning; Johann Hipp; Hans-Jeorg Nuesslin
Original assignee: Siemens AG
Current assignee: SICK IBEO GmbH; Siemens AG
Priority date: 1989-08-08
Filing date: 1990-08-07
Publication date: 1993-04-01
Anticipated expiration: 2010-08-07
Also published as: EP0412395A1; EP0412395B1; AU6027990A; DE59007213D1; ATE111994T1

Abstract

The invention relates to the steering of a bucket wheel excavator (6) for producing planned surfaces in open-cast mining, in particular in quarrying and open-cast lignite mining, by a continuous measurement of the area exposed by the bucket wheel and controlled follow-up of the bucket wheel into the required position for producing the predetermined surface, the bucket wheel being steered by a pulsed laser beam produced in a rotary laser (8, 9) carried along by the machine. <IMAGE>

Description

S F Ref: 137511 FORM COMMONWEALTH OF AUSTsLI PATENTS ACT 16 7 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 D-8000 Munich 2 FEDERAL REPUBLIC OF GERMANY Rheinbraun Aktiengesellschaft Stuttgenweg 2 D-5000 Koln 41 (Lindenthal) FEDERAL REPUBLIC OF GERMANY IBEO-Ingenieurburo fur Elektr'onik 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 0 Address for Service: Complete Specification for the invention entitled: Guidance of an Excavator Bucket Wheel for Generating Predetermined Surfaces The following statement is a full description of this invention, including the best method of performing it known to me/us 5845/3 I Abstract Guidance of an excavator bucket wheel for generating predetermined surfaces The invention relates to the guidance of an excavator bucket wheel for generating predetermined surfaces in open-cast mining, especially in hard-coal and brown-coal open-cast mining, by a continuous surveying of the surface exposed by the bucket wheel and by a controlled follow-up of the bucket wheel into the necessary position for generating the predetermined surface, the guidance of the bucket wheel taking place by means of a pulsed laser beam generated in a rotary laser carried along by the open-cast mining appliance.

FIG. 1 *.s

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LA- GR 89 P 8569 E/Foreign Siemens Aktiengesellschaft RHEINBRAUN Rheinische Braunkohlenwerke Aktiengesellschaft IBEO Ingenieurbiro fur Elektronik und Optik Guidance of an excavator bucket wheel for generating predetermined surfaces The invention relates to guidance of an excavator bucket wheel for generating predetermined surfaces, for example a track level or slope, in open-cast mining, especially in hard-coal or brown-coal open-cast mining, by a continuous surveying of the surface exposed by the bucket wheel and by a follow-up of the bucket wheel into the necessary position for generating the predetermined surface.

S* For the operation of a bucket-wheel excavator, in 15 the mining of coal, ore or other materials to be conveyed, it is essential to predetermine the standing surface of the appliance, varying during the working advance, so that the latter can perform its mining tasks.

The problem has hitherto been solved at a very high outlay, with the inclusion of manual steps, as regards both surveying and the guidance of the bucket wheel. A corresponding solution is known from the periodical "Braunkohle 41 (1989) Number 5, page 148-150.

The object of the invention is to design the guidance of an excavator bucket wheel for generating predetermined surfaces in open-cast mining in such a way that the predetermined surfaces are obtained automatically with high accuracy.

The object is achieved in that the guidance of the bucket wheel takes place by means of a pulsed laser beam which is generated in a measuring laser carried along by the open-cast mining appliance and which measures the contour of the generated surface.

Suitable lasers are known in principle, for example from the book "Lasertechnik: Eine Einfihrung", SHo Th 13.07.1990 -2ems..

'o *5 Si HUthig Verlag, Heidelberg, 1982, page 368ff. The known lasers are used both for measurement in open-cast mining and for the guidance of working machines, for example band-return tracklayers. However, it has not thereby been possible to obtain a predetermined surface form automatically during the working of the excavator.

In accordance with the present invention there is disclosed a method for controlling the position of an excavator bucket wheel for generating desired surfaces in open-cast mining whereby the contour of the surface generated by the bucket wheel is continuously scanned by means of a pulsed laser beam which is generated in a laser scanner carried along the excavator, measuring values of the scanned surface are generated dependent on the present angle and the transit-time of the laser light thereby determining the distance between the laser scanner and the scanned points of the surface, said measuring values are compared to predetermined values corresponding to a desired contour of the surface, and the position of the bucket wheel is controlled dependent on the difference between the measuring values and the predetermined values.

In an embodiment of the invention, the measuring laser is 20 positionally oriented via a perpendicular sensor, and it detects the course of the exposed surface via transit-time measurements of laser light which are determined in a computer. This advantageously provides a positionally independent determination of the course of the exposed surface via reference lines, between which the exact surface course can easily be determined by interpolation. The determination can be carried out either by the computer, which also evaluates the transit time of the laser light and consequently determines the distance of the laser from the individual points of the exposed surface, or in a computer which can serve at the same time as a control computer.

The position of the laser carrying out the continuous measurements is optionally either in the vicinity of the bucket wheel or on the mast of the excavator, but in any event such that an undisturbed measurement of the exposed surface (track level) is possible. The exact choice of the position of the laser depends on the remaining tasks assigned to the laser and the computer, such as, for example, collision monitoring or deposit-course monitoring.

DT 1815o 2A 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, given by way of example and in conjunction with a cut-volume measurement: Figure 1 shows a view of the working location, Figure 2 shows a representation of the geometrical relations in a cut-volume measurement, and Figure 3 shows a representation of the geometrical relations at the working location in simplified 1815o 3 GR 89 P 8569 E/Foreign 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. A mounting on the excavator is likewise possible and is recommended when there is a large amount of dust generated. The use of IR lasers which work, for example, at pulse durations of 1-10 nanoseconds and at a pulse rate in the kilohertz range, preferably in the 3-30 kHz range is particularly suitable.

The profile is determined from pairs of distance/ angle values. The profile 1, 2 of 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 se. 20 direction, the second profile scanner can also be omit- *ted. 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 25 material cutaway) 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 So• particular cut 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 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 4 GR 89 P 8569 E/Foreign 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 excavator and its position in space are necessary for the calculation. This information can easily be stored in the compter 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 Sgo with the pivoting speed, the information is sufficient to calculate the solid-material volume flow from the profile ee 20 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 16 is in an oblique position, it may be necessary to make a correction which can be determined 25 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) 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 5 GR 89 P 8569 E/Foreign 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 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.

The foregoing invention, which solves a basic problem hitherto considered insoluble in the work of bucket-wheel excavators, can preferably be put into practice by means of laser scanners, especially IR laser scanners. It is obvious to a person skilled in the art, however, that other radiation sources comparable to a laser can also be used, for example electromagnetic e O' 20 emitters of very high frequency and with a comparable beam focusing. However, it is advantageous to use IR measuring lasers which have pulse durations of 1-10 nanoseconds and a pulse rate in the kilohertz range, preferably in the 3-30 kHz range.

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Claims

2. Method according to claim 1, whereby for measuring the transit-time of the laser light a starting pulse is first generated, a reflected fraction of this is lengthened in i terms of transit-time via delay lines and is used for a start-stop measurement. 3 Method according to claim 1 or 2, whereby the laser scan- ner ist designed as an IR laser working at pulse durations *5 o of 1 10 nanoseconds and a pulse rate in the kilohertz range. S SI
4. Method according to claim 3, wherein the pulse rate is between 10 an 50 kHz. Method according to claim 1, 2, 3 or 4, whereby the laser scanner is positionally oriented via a perpendicular sensor. 7
6. Method according to claim 1, 2, 3, 4 or 5, whereby the actual contour of the scanned surface is calculated from the measuring values, which describe the distance between the laser scanner and the scanned points of the surface, and from parameter values relating to geometrical dimensions of the excavator and to the position of the laser scanner on said excavator.
7. Method according to claim 1, 2, 3, 4, 5 or 6, whereby in angular sectors of the laser beam not used for the scan ning of the surface, the laser scanner measures in relation to a target within the excavator, and the distance thus mea- sured is used as a checking value and calibration value for the measuring of the surface generated by the bucket wheel.
8. A method for controlling the position on an excavator bucket wheel substantially as described herein with reference to the drawings. SS DATED this FIRST day of FEBRUARY 1993 Siemens Aktiengesellschaft, Rheinbraun Aktiengesellschaft, IBEO-Ingenieurburo fur Elektronik und Optik J. Hipp G. Broehan *i Patent Attorneys for the Applicant S' SPRUSON FERGUSON 6 S S a @0r