Earth working – Automatic power control – Land leveller type
Reexamination Certificate
1998-12-21
2001-02-20
Novosad, Christopher J. (Department: 3671)
Earth working
Automatic power control
Land leveller type
C701S050000
Reexamination Certificate
active
06189626
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to the field of guidance and control systems for mobile machines. More particularly, the present invention relates to techniques for accurately positioning a tool on a mobile machine.
BACKGROUND OF THE INVENTION
Various technologies have been developed to accurately position a tool on a mobile machine. These technologies are useful in applications such as construction, mining, and other industries, in which it may be necessary to maintain very tight tolerances. On a construction site, for example, it may be necessary to add or remove earth from a given location to accurately provide a specified design elevation, which may be different from the initial surface elevation. A machine such as an excavator, grader, or bulldozer equipped with a bucket, blade, or other appropriate tool is typically used. Accurate positioning of the tool is critical for achieving the required accuracy.
Some machine control systems rely upon a stationary rotating laser or a robotic total station to assist in accurately positioning the tool. However, such systems are limited to operation with only one machine at a time. In addition, laser based systems tend to be limited by line of sight. Thus, obstructions in the work area, such as other machines, may impair operation of the system. Further, many such systems are effective only when used on very level terrain. Hence, what is needed is a system for accurately positioning a tool on a mobile machine, which overcomes these and other disadvantages of the prior art.
SUMMARY OF THE INVENTION
The present invention includes a method and apparatus for enabling accurate positioning of a tool on a mobile unit operating within an area. Data representing a specified coordinate for various locations in the area are stored, and the current location of the mobile unit is determined. A command is then generated based on the current location of the mobile unit and the data. The command is transmitted from the mobile unit to a stationary device. The stationary device generates a beam and responds to the command by adjusting the beam. The beam is then detected at the mobile unit, and an adjustment of the tool is determined at the mobile unit by using the beam as a reference.
Another aspect of the present invention is a method and apparatus for enabling accurate positioning of a tool on a mobile unit, according to which a laser beam is generated to define a reference coordinate for use in positioning the tool. In particular embodiments, the reference coordinate may be an elevation. In the method, first data indicating the current location of the machine is received, and second data representing specified coordinates for a plurality of locations within the work area is maintained. The second data is accessed to determine a specified coordinate corresponding to the current location of the machine, and a coordinate of the laser beam is adjusted based on the specified coordinate to adjust the reference coordinate.
Yet another aspect of the present invention is a method and apparatus for enabling accurate positioning of a tool in a mobile unit, according to which an on-board subsystem in the mobile unit is operated in both a guidance only mode and an automatic mode. Operation in the guidance only mode includes operating the on-board subsystem to automatically compute a first adjustment of the tool, and outputting an indication of the first adjustment to an operator to guide the operator in manually positioning the tool. Operation in the automatic mode includes operating the on-board subsystem to automatically compute a second adjustment of the tool, and then automatically positioning the tool based on the second adjustment. In particular embodiments, the on-board subsystem is automatically switchable between the two modes in response to the occurrence of a predefined condition.
Still another aspect of the present invention is a method and apparatus for enabling an operator of a mobile machine operating in a work area to accurately position a tool of the machine, according to which design coordinates for a plurality of locations within the work area are stored, and the current location of the machine is determined. A desired adjustment of the tool is then automatically computed, based on the current location of the machine and the design coordinates. An indication of the computed desired adjustment is then displayed to an operator of the tool.
Other features of the present invention will be apparent from the accompanying drawings and from the detailed description which follows.
REFERENCES:
patent: 5453738 (1995-09-01), Zirkl et al.
patent: 5471391 (1995-11-01), Gudat et al.
patent: 5551518 (1996-09-01), Stratton
patent: 5600436 (1997-02-01), Gudat
patent: 5612864 (1997-03-01), Henderson
patent: 5640323 (1997-06-01), Kleimenhagen et al.
patent: 0811727A1 (1997-12-01), None
Blakely , Sokoloff, Taylor & Zafman LLP
Novosad Christopher J.
Trimble Navigation Ltd.
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