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Productivity increases using machine control systems lead to less labor, less
fuel, less machine maintenance, and ultimately, more profit.
Field General allows contractors to create 3D machine
control site models easily, allowing the maximum return on investment.
How does a machine control system work?
A machine control system compares the current
location of a machine blade with the desired grade at that location and either
displays the difference (indicate systems), or automatically makes a blade adjustment.
The current location of the machine is obtained either by
GPS (Global Positioning System) or a robotic total Stations, after orientation
to the site using known control points.
The desired grade at each location is provided by a special
file containing a Triangulated surface (TIN). Unlike a staking file, a
triangulated surface file contains a 3D elevation for every location on the
site.
To
understand how a TIN file works, study the animated file to the right. The known
spot elevations (30,29, 31) at the corners of the triangle are used to
interpolate any elevation on the triangle.
Three calculated points are shown, but a machine control
system using this triangle for desired grade could sample this triangle anywhere
and get a grade. Triangulation files normally contains thousands of these
triangles.
Making a Machine Control Model
Traditional grading using grade stakes requires operators
to possess an understanding of grading objectives between stakes. This is done
on the site using the information available on the site plan.
With machine control systems, proper interpretation of
grade between known data points needs to be done to the file before it can be
used. Many buyers of machine
control equipment are lead to believe a CAD file will create a machine control
file. We've all heard a salesperson proclaim "just get the CAD file, load it and
go".

Consider the illustration above. It is an
uncorrected file obtained by loading the CAD file, and triangulating the
proposed information. The highlighted blue triangle does not hold the crown of
the road properly. A study of the file indicates many other problems.
Here is the same file corrected, using offsets, trims and
snaps, for machine control
grading:

The machine operator sees this on his display
(courtesy Topcon Positioning Systems), and the blade
is constantly adjusted to the desired value from the triangulated (TIN) surface
model.


Creation of surface models for Topcon, Trimble, Leica and
LandXML are fully supported by Field General.
Call us at 1(877)746-7483 to set up a demonstration
of how InSite SiteWork and Field General can import and export points, offsets
and create machine control models
3DLIVE


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