Data processing: measuring – calibrating – or testing – Calibration or correction system – Position measurement
Reexamination Certificate
1999-01-15
2001-06-26
Tarcza, Thomas H. (Department: 3662)
Data processing: measuring, calibrating, or testing
Calibration or correction system
Position measurement
C342S357490, C342S357490, C342S457000, C702S094000
Reexamination Certificate
active
06253160
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to systems for controlling the positioning of a tool on a mobile machine. More particularly, the present invention relates to a technique for calibrating a mechanism for positioning a tool on a mobile machine.
BACKGROUND OF THE INVENTION
Mobile machines such as excavators, bulldozers, and graders are commonplace in applications such as construction and mining. These machines include a tool, such as a bucket or a blade, which is positioned by a tool positioning mechanism under the control of a human operator or an on-board tool control system. For example, referring to
FIG. 1
, which shows an excavator
1
, the tool may be a bucket
2
, and the tool positioning mechanism
3
may comprise an arm
5
and a boom
6
, to which the bucket
2
is mounted.
To allow accurate positioning of the tool, an on-board tool control or guidance system may require precise knowledge of the position of the tool relative to a reference position, such as the ground level. Accordingly, on machines such as those mentioned above, the tool positioning mechanism sometimes is equipped with linear or angular position encoders or other similar sensors. The outputs of the encoders are provided to the tool control system to indicate the physical configuration of the positioning mechanism and the position of the tool. A common problem is that, over time, position inaccuracy tends to accumulate in the linkages of the tool positioning mechanism. This inaccuracy tends to be reflected in the outputs of the encoders. Because the outputs of the encoders can be crucial in positioning the tool, it may be desirable to calibrate the encoders before beginning a task, to ensure that the tool control system uses reliable data. The encoders may be calibrated by setting their outputs to a known value when the position of the tool is precisely known, relative to a reference (e.g., the ground level).
One possible calibration approach involves distributing a number of stakes or other similar reference points around the job site, each of which has a visible mark at a precisely known height. The machine is driven close to a stake, the tool is aligned with the mark, and the tool positioning system is then calibrated. This approach is undesirable, however, because it requires time and manpower to survey the stakes. In addition, the tool positioning system can only be calibrated when the machine is located next to one of the stakes.
Another calibration technique uses a laser beam at a fixed, precisely known height as a reference level. The laser beam is detected by a photosensor on-board the machine. The use of a laser beam, however, is subject to line of sight limitations. Thus, obstacles on the job site can hinder calibration of the tool control system when such a technique is used.
What is desired, therefore, is a technique for calibrating a tool positioning system on a mobile machine which overcomes these and other disadvantages. In particular, what is desired is a technique for calibrating a tool positioning system on a mobile machine in a stakeless environment without the line of sight limitations associated with
SUMMARY OF THE INVENTION
The present invention includes a method and apparatus for calibrating a tool positioning mechanism on a mobile unit. A mobile unit includes a tool, a mechanism for positioning the tool, a sensor, a positioning system, and a processor. The positioning system is configured to acquire positioning data while the mechanism is in a predetermined configuration and to precisely determine the position of the tool. The sensor provides signals which indicate the physical configuration of the mechanism. The processor is configured to cause the sensor to be calibrated based on the precisely determined position 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: 3815250 (1974-06-01), Roodvoets et al.
patent: 4221483 (1980-09-01), Rando
patent: 4225226 (1980-09-01), Davidson et al.
patent: 4231700 (1980-11-01), Studebaker
patent: 4600997 (1986-07-01), Cain et al.
patent: 4653910 (1987-03-01), Poling
patent: 4674870 (1987-06-01), Cain et al.
patent: 4676634 (1987-06-01), Petersen
patent: 4732471 (1988-03-01), Cain et al.
patent: 4733355 (1988-03-01), Davidson et al.
patent: 4756617 (1988-07-01), Cain et al.
patent: 4767208 (1988-08-01), Cain et al.
patent: 4805086 (1989-02-01), Nielsen et al.
patent: 4807131 (1989-02-01), Clegg
patent: 4829418 (1989-05-01), Nielsen et al.
patent: 4830489 (1989-05-01), Cain et al.
patent: 4888890 (1989-12-01), Studebaker et al.
patent: 4895440 (1990-01-01), Cain et al.
patent: 4914593 (1990-04-01), Middleton et al.
patent: 4924374 (1990-05-01), Middleton et al.
patent: 4926948 (1990-05-01), Davidson et al.
patent: 5076690 (1991-12-01), deVos et al.
patent: 5078215 (1992-01-01), Nau
patent: 5107932 (1992-04-01), Zachman et al.
patent: 5137354 (1992-08-01), deVos et al.
patent: 5184293 (1993-02-01), Middleton et al.
patent: 5235511 (1993-08-01), Middleton et al.
patent: 5243398 (1993-09-01), Nielsen
patent: 5327345 (1994-07-01), Nielsen et al.
patent: 5334987 (1994-08-01), Teach
patent: 5375663 (1994-12-01), Teach
patent: 5465493 (1995-11-01), Sobottke et al.
patent: 5477459 (1995-12-01), Clegg et al.
patent: 5519620 (1996-05-01), Talbot et al.
patent: 5559725 (1996-09-01), Nielson et al.
patent: 5572809 (1996-11-01), Steenwyk et al.
patent: 5583685 (1996-12-01), Ohtomo et al.
patent: 5621531 (1997-04-01), Van Andel et al.
patent: 5638220 (1997-06-01), Ohtomo et al.
patent: 5689330 (1997-11-01), Gerard et al.
patent: 5711022 (1998-01-01), Steenwyk
patent: 5742069 (1998-04-01), Steenwyk et al.
patent: 5751459 (1998-05-01), Ohtomo et al.
patent: 0219767 (1987-04-01), None
patent: 0223043 (1987-05-01), None
patent: 0257525 (1988-03-01), None
patent: 0262764 (1988-04-01), None
patent: 0346044 (1989-12-01), None
patent: 0346043 (1989-12-01), None
patent: 0349132 (1990-01-01), None
patent: 0358368 (1990-03-01), None
patent: 0369694 (1990-05-01), None
patent: 0405725 (1991-01-01), None
patent: 0426287 (1991-05-01), None
patent: 0452974 (1991-10-01), None
patent: 0452975 (1991-10-01), None
patent: 0457548 (1991-11-01), None
patent: 0223043 (1992-01-01), None
patent: 0468677 (1992-01-01), None
patent: 0501616 (1992-09-01), None
patent: 0219767 (1992-12-01), None
patent: 0542015 (1993-05-01), None
patent: 0349132 (1993-08-01), None
patent: 0346044 (1994-01-01), None
patent: 0358368 (1994-04-01), None
patent: 0426287 (1994-04-01), None
patent: 0452974 (1995-01-01), None
patent: 0452975 (1995-12-01), None
patent: 0468677 (1996-05-01), None
patent: 0457548 (1996-07-01), None
Brown, Steve, “Automatic Excavator Control. Laser Technology Enables Excavator Operators to Obtain Fast, Pinpoint Control of Slope, Depth and Material Placement,”Equipment Today, Jun. 1998, pp. 16-18.
Ries, Richard, “Topcon in 3-D”,Equipment World, Mar. 1998, p. 27.
Moore, Walt, “Grade-Control System Creates Virtual Stringline: Topcon's New System is aimed at Improving Productivity by Eliminating Staking and Checking”,Construction Equipment, Mar. 1998, vol. 97, No. 3, pp. 105.
Larry Stewart, “Three-Dimensional Control Replaces Stakes, String Lines,”Construction Equipment, p. 85.
Description of Topcon GRT-2000, Construction Equipment, “Equipment Ideas.”
Advertisement for Topcon Corporation, International Construction, Mar. 1998, vol. 37, No. 3.
Advertisement for Topcon Corporation, “Enter a New Dimension of Grade Control,” Equipment World, Jul. 1998.
Advertisements, Construction Monthly, p. 45, May 1998.
Advertisement for Topcon Corporation, “Cubrimos un Mundo de Aplicaciones,” Construccion y Obras Publicas Latinoamerica, vol. 5, No. 5, Aug. 1998.
Advertisement for Spectra Precision, “Laser-Based Technology for Your Down-to-Earth Problems,” Construction & Public Works Asia, vol. 5, No. 5, Aug. 1998.
Blakely , Sokoloff, Taylor & Zafman LLP
Mull Fred H.
Tarcza Thomas H.
Trimble Navigation Ltd.
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