Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Construction or agricultural-type vehicle
Reexamination Certificate
2002-03-25
2003-12-30
Black, Thomas G. (Department: 3663)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Construction or agricultural-type vehicle
C701S207000, C340S988000, C367S069000, C342S357490
Reexamination Certificate
active
06671600
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to a method of producing a useful form according to a theoretical model, more particularly a projected useful form from an existing body delimited by a three-dimensional envelope using a tool mounted on a machine cooperating with a global satellite positioning system of the bifrequency, differential, kinematic and real time type such as GPS, the machine having at least one global positioning receiver in order to be moved according to a theoretical model of the form.
BACKGROUND OF THE INVENTION
The purpose is to produce a useful form with at least one surface, defined by the movement along an arch axis of another transverse curve, in general polygonal, possibly variable. Such a surface is referred to as a topographical profile. Such a profile must be as close as possible to a projected theoretical profile referred to as a model.
This model, for example defined by means of computer aided construction software, represents the useful form to be produced. In practice, these useful forms have faults or imperfections compared with the model, which it is necessary to remove in order to ensure that this form meets the requirements. Thus, in order to evaluate the quality of evenness of road projects, a notation system has been set up.
These defects are detected by physical measurement in situ and quantified from a numerical analysis of the unevennesses along the profile of the roadway, by physical measuring appliances. The magnitude of these defects is between a few millimetres for the smallest, and a few tens of millimetres for the largest. According to the magnitude measured, a grade known as the LPA (Longitudinal Profile Analysis) grade lying between 0 and 10 is attributed to the useful form. The grade 0 is then attributed to a useful form whose defects have a magnitude of a few tens of millimetres. For defects whose magnitude does not exceed a few millimetres, the grade 10 is attributed to the useful form.
To produce such useful forms in practice, three techniques are normally employed. One technique consists of guiding at least one site machine along wires installed on site. These wires give physical expression to the arch axis which the machine must travel along. In practice, wire guidance does not make it possible to produce useful forms having one or more complex surfaces as easily and rapidly as simple useful forms. This is because only two dimensions in space are apprehended, and the notation of the useful road forms thus obtained does not in general exceed 6.
Another technique consists of guiding site machines along laser beams, which give physical expression to the arch axis, formed by one or more straight sections, which the machines have to travel along in order to produce the useful form. The successive positionings of the machine are obtained from its initial position, considering that it follows the arch axis, by measuring the distance travelled from the origin, calculating, by means of the laser, an actual position of the machine with respect to the curve, and attempting to make this position coincide with the required curve. When useful forms are produced having one or more complex surfaces, this guidance requires frequent repositioning of the lasers.
In addition, because of the optical nature of the laser, it is essential to avoid the interposing of physical obstacles between an optical source and its receiver. However, such obstacles, such as other machines on the site (compacter, bulldozer, lorries, earth movers or the like) frequently cut the laser beam, requiring interruption of the operation or production guided by the laser.
In addition, geometric variations within certain useful forms complicate or even prevent the use of laser guidance: interchange roads can for example be cited.
Finally, the use of a laser is complex or even possible for useful forms whose arch axis has small radii of curvature, such as in road interchanges.
Yet another known technique consists of using GPS systems. The document U.S. Pat. No. 5,631,658 can thus be cited, which describes a machine guidance method, for an earthwork machine for example, by means of a GPS system. This document makes provision for storing a first three-dimensional model representing the required geography of a site, and a second three-dimensional model representing the actual geography of this site as it is produced. The two models are compared with means which represent, in digital signals and in real time, the instantaneous three-dimensional position of the machine whilst it is travelling on the site. Other means determine and update the difference between the two geographical models, in real time. Whilst the means control the machine, according to this difference.
One drawback of this method is that it requires computer storage and processing means capable of taking the two three-dimensional models into consideration, which turns out to be complex to implement in practice. In addition, in the useful forms having several juxtaposed surfaces, it is difficult in practice to obtain precise connections between these surfaces, with the known GPS guidance systems. Also, the known GPS guidance systems do not make it possible to work indifferently in one direction or in the other along the arch axis, which requires a certain amount of rigidity in the working method.
The invention therefore aims to permit the production of useful forms, dispensing with the drawbacks mentioned above, amongst others.
One aim of the invention is thus to permit the production of useful forms for road projects, whose LPA notation is greater than 8, preferably equal to 10, with a precision in terms of elevation of ±13 mm. To this end, a first object of the invention is a method of producing a projected useful form such as a road project surface, from an existing body delimited by a three-dimensional envelope, such as a construction site, building or the like, using a tool mounted on a machine, for example an earthwork machine for a site or similar. This machine cooperates with a global positioning by satellite system of the dual-frequency, differential and kinematic type and in real time, such as GPS; and has at least one global positioning receiver, for example on a tool, in order to be moved according to a theoretical model of the useful form.
According to one characteristic, this method includes the steps making provision for:
storing fixed geometric curves peculiar to the useful form, including at least one substantially longitudinal arch axis and at least one cross-sectional profile;
measuring, at at least one moment, the elevation, longitudinal and transverse position of the tool, using a global positioning receiver when the tool is moved, for example at a predetermined frequency;
associating a position along the arch axis with this measured position;
locally calculating the theoretical model whilst making a cross-sectional profile of the useful form correspond to this location;
activating in memory a standard deviation signifying an uncertainty characteristic of the global positioning system, possibly after it is determined during a phase of calibrating the receiver;
comparing, during the movement of the tool, for example at a predetermined frequency, a measured elevation position of the tool with a theoretical altitude defined from the model;
deducing from this comparison a deviation in elevation at the time of measurement, such that this deviation is said to be a zero deviation when the measured elevation position is substantially the same as the theoretical altitude;
defining on the one hand at least from the zero deviation at least two analysis bands, for example two centre bands respectively upper and lower, two median bands respectively upper and lower, and two external bands respectively upper and lower, these bands being for example symmetrical in pairs, lower and/or,upper delimiters of these analysis bands being proportional to the standard deviation;
identifying an active analysis band to which this deviation in elevation belongs;
calculating, according to the de
Black Thomas G.
GTM Construction
Nawrocki, Rooney & Sivertson P.A.
To Tuan C
LandOfFree
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