Harvesters – Motorized harvester – With condition-responsive operation
Reexamination Certificate
2000-04-05
2002-05-21
Pezzuto, Robert E. (Department: 3671)
Harvesters
Motorized harvester
With condition-responsive operation
C172S004500, 36
Reexamination Certificate
active
06389785
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates generally to agricultural machinery and, more particularly, to improvements to agricultural machinery for harvesting crops having an apparatus for contactless scanning of contours extending over the ground.
An apparatus generally of this kind is known from the article “Swath Scanning with Ultrasound” (periodical: Landtechnik 5-93, pages 266-268). The apparatus described there consists of a plurality of ultrasound sensors which are arranged on a fastening strip at a distance of 40 cm from each other and are directed vertically onto the ground. This fastening strip may, for example, be mounted on agricultural equipment such as a forager or an agricultural machine towing a baling press. By means of the ultrasound sensors the height a swath, for example of straw or green fodder, above the ground can be determined at certain points, allowing the contour of the swath over the ground to be scanned along a horizontal line. The device described therein, however, has at least a few significant drawbacks. That scanning device is relatively expensive because several ultrasound sensors are necessary for scanning. Furthermore there is insufficient distance between the ultrasound sensors and, as a result, the ultrasound sensors have a disturbing effect on each other due to inadequate focusing of the sound lobes. This limits the horizontal resolution or density of measuring points of contour scanning.
Furthermore the distance of the ultrasound sensors from ground or the contour to be scanned must not become too great (not more than about 1.2 m.), because the resultant relatively high divergence of the sound lobes to the ultrasound sensors have a disturbing effect on each other. A sufficiently low height of mounting on the agricultural machinery is often difficult to achieve simply for structural reasons. Moreover such a bulky and low-set fastening strip with several ultrasound sensors is very easily damaged when used in the field. Increasing the height at which the fastening strip is set, however, is possible only if the distance between the ultrasound sensors on the fastening strip is also increased, which in turn means a lower horizontal resolution of swath contour scanning.
The attempt to reduce the minimum distance between the ultrasound sensors by implementing adjacent sensors that measure alternately, rather than simultaneously, requires an elaborate control circuit for the individual ultrasound sensors.
For forward-looking contour scanning such as would be necessary for example for automatic steering along the scanned swath contour, the fastening strip with the ultrasound sensors would have to be mounted in an elaborate and tedious manner on an additional holding linkage arranged at the front of the agricultural machinery and extended forwardly.
Another drawback of the known scanning apparatus lies in that the accuracy and reliability of scanning crop material by means of ultrasound greatly depends on the nature and properties of the crop material and on weather conditions.
Eggenhaus (U.S. Pat. No. 5,937,621) discloses an automatic system to control the cutting height and the reel height by an adjusting device which adjust the height of both by stored values. This system is needed if there is a change between standing and laying crop. Both, the cutting height and the reel height should be changed then. But if only the standing crop height changes, only the reel height must be changed without a change in the cutting height. This could be done by a manual adjustment from the operator. The absolute height of the stubble or the standing crop is not measured.
It is an object of the present invention to provide an apparatus on agricultural machinery for contactless scanning of contours extending over the ground, which eliminates the drawbacks of the devices described above. A further object of this invention is to provide a way to calculate the cross-sectional area.
A further object of this invention is to calculate an inclination offset.
A further object of this invention is to use the inclination offset when calculating contour information.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided an agricultural machine having an apparatus for contactless scanning of contours extending over the ground comprising a laser distance measuring device, which has a laser beam transmitting and receiving device that determines the distance from a contour point by measuring the running time of the laser scanning beam emitted and reflected at the contour point. The laser scanning beams are pivotal within a certain angular range stepwise or steplessly in a scanning beam plane. In one embodiment the laser distance measuring device is mounted on the agricultural machine such that the scanning beam plane is inclined to the ground at an acute angle forwards in the direction of travel. With the aid of an analyzer, for each pivot angle from the measured distance, the arrangement and orientation of the laser distance measuring device on the agricultural machine (mounting height, angle of inclination to ground) is determined, as well as the position of the contour point corresponding to the pivot angle (vertical and horizontal position above the ground).
In accordance with another feature of the present invention there is provided a method of contour scanning during travel of an agricultural machine including the steps of providing a laser beam transmitting and receiving device; continually scanning the laser beam across the contour of the field in front of the machine; measuring the distance values from the laser beam; determine the contour of the field across the scanning width; and storing the contour information.
The use and arrangement of a laser distance measuring device embodying the invention has considerable advantages over the prior art scanning device described above.
Only one laser beam transmitting and receiving device is needed for the scanning device embodying the invention. Thus, this scanning device is considerably less expensive than the known ultrasound scanning device which requires several ultrasound sensors. The apparatus embodying the invention scans a contour in front of the agricultural machine at various points transverse to the direction of travel by pivoting the laser scanning beam. Thus the number of scanning points on a scanning line is substantially greater than with the ultrasound scanning device. Thus for example with a pivot angle range of ±45° and pivoting of the laser scanning beam in 0.5° steps, the result is 180 scanning points. Due to the low divergence of the laser scanning beam a relatively high resolution (density of scanning points) can be obtained, as the centers of adjacent scanning points lie close to each other without the scanning spots overlapping on the contour. Furthermore, unambiguous assignment of the point of reflection is possible.
Adjacent sensors do not adversely affect each other as with the prior-art scanning device, because the distances from the contour points are determined successively.
Scanning a significant distance ahead, such as is necessary for automatic steering along a scanned contour, can be achieved in a simple manner with the device embodying the invention. Thus, for example with a mounting height 380 cm. above the ground on an agricultural machine and an angle of inclination to the ground of 65°, a scanning distance in front of the agricultural machinery of approximately 8.15 m can be obtained. Due to the low divergence of the laser scanning beam, the scanning distance is not limited as in the case of ultrasound sensors. Contour scanning which may be achieved at relatively great distances cannot be achieved with the prior-art ultrasound scanning device. This would require a correspondingly long holding linkage in front of the agricultural machinery for receiving the fixing strip for the ultrasound sensors, which would cause the whole system to become completely impracticable.
Reflection of the laser scanning beam, unlike ultrasound, is relatively indep
Diekhans Norbert
Huster Jochen
Claas Selbstfahrende Erntemaschinen GmbH
Husch & Eppenberger LLC
Kovács Árpád F
Muir Robert E.
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