Communications: directive radio wave systems and devices (e.g. – Directive – Including a satellite
Reexamination Certificate
1999-06-01
2001-02-20
Blum, Theodore M. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Directive
Including a satellite
C701S215000, C037S348000
Reexamination Certificate
active
06191733
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is related in general to the field of equipment automated control and, in particular, to a system for determining the position and orientation of various components of a work machine operating on the grounds of a surface mine.
2. Description of the Related Art
Surface mines utilize a variety of work machines for excavating and transporting ore, grading and stabilizing roadways and slopes in the mine pit, and providing all support functions necessary to the operation of a mine. Most work machines, such as excavators, shovels, backhoes and the like, are human-operated, mobile pieces of equipment constantly being moved around on the surface of the mine. Skilled operators ensure that each work machine is positioned in the right place and optimally oriented to perform its intended function. For example, an excavator operator will ensure that the undercarriage of the machine is sufficiently close to the minable seam and that its boom is oriented so as to permit the bucket of the machine to reach and extract a full load of ore.
In order to improve safety and efficiency, much effort is currently under way to develop automated systems for controlling the operation of work machines in surface-mine and other environments. The ability to determine the exact position of critical components of a working machine, such as the bucket of an excavator, is a very important feature of any such effort to automate certain aspects of a mining operation. Accordingly, various positioning systems have been developed in this and related arts based on the properties of various triangulation tools such as lasers, radio, microwave, radar, and the Global Position System (GPS).
For example, in U.S. Pat. No. 5,438,771, Sahm et al. describe a system for determining the location and orientation of a work machine having a fixed undercarriage supporting a car body rotatably connected to it. The system utilizes a GPS unit placed on the car body at a place removed from its axis of rotation. By collecting at least three coordinate positions of the GPS antenna as the car body rotates over its stationary undercarriage, the plane corresponding to the orientation of the machine and the position of the axis of rotation can be calculated. Based on these data, the current position of the GPS antenna, and the geometry of the machine, the position and orientation of every critical component of the machine can be determined and used for controlling its operation.
Because of the requirement that at least three positions of the GPS antenna be recorded along an arc of rotation, the system disclosed in the '771 patent is only applicable to work machines that include a rotating body over a transport undercarriage. In addition, the system requires that the undercarriage be kept stationary during measurements and that at least three data points be collected before the plane of orientation can be determined every time the work machine is moved to a new work site. Therefore, this method and apparatus are not suitable for continuous tracking of the position of mine vehicles or for controlling equipment lacking a rotating body. The present invention provides a procedure and apparatus that overcome these deficiencies.
BRIEF SUMMARY OF THE INVENTION
The primary objective of this invention is a method and apparatus for determining the position and orientation of critical components of a work machine operating on the surface of a work site.
Another important goal of the invention is a system of general application to all kinds of equipment, irrespective of their specific geometry and whether or not they include a rotating component.
Another objective is a system that provides continuous position and orientation information while the work machine is stationary as well as when it is moving along the surface of the work site.
Another goal is a system that can be implemented in conjunction with conventional control algorithms and/or hardware.
Still another objective is a system that is suitable for incorporation within existing work-machine instrumentation.
A final objective is a system that can be implemented easily and economically according to the above stated criteria.
Therefore, according to these and other objectives, the preferred embodiment of the present invention consists of utilizing two GPS units judiciously mounted at two separate points on the body of a work machine to periodically measure their three-dimensional coordinates with respect to a chosen reference system. As soon as two sets of measurements are recorded, a plane is fitted through the four points so collected and it is used to determined the current orientation of the machine. As each additional set of position data is collected for the two points on the machine at predetermined intervals, a new plane equation is calculated to update the orientation of the machine based on a predetermined number of prior measurements. Standard-deviation analysis is used to check the validity of each plane calculation and the process is restarted when the deviation is found to be greater than an acceptable parameter. Based on the current coordinates of the two GPS antennae, the current orientation plane so calculated, and the known geometry of the work machine, the current position of its critical components can be determined as well irrespective of the specific motion pattern of the machine.
Various other purposes and advantages of the invention will become clear from its description in the specification that follows and from the novel features particularly pointed out in the appended claims. Therefore, to the accomplishment of the objectives described above, this invention consists of the features hereinafter illustrated in the drawings, fully described in the detailed description of the preferred embodiment and particularly pointed out in the claims. However, such drawings and description disclose but one of the various ways in which the invention may be practiced.
REFERENCES:
patent: 5404661 (1995-04-01), Sahm et al.
patent: 5438771 (1995-08-01), Sahm et al.
patent: 5546093 (1996-08-01), Gudat et al.
patent: 5951613 (1999-09-01), Sahm et al.
patent: 6052647 (2000-04-01), Parkinson et al.
Blum Theodore M.
Durando Antonio R.
Modular Mining Systems, Inc.
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