Automated Machine Guidance
(AMG)
What is machine control?
• Machine control involves the integration of
positioning tools into construction machinery.
• Many hardware and software solutions exist with
the sole purpose of determining a machine's
current position on the earth and then comparing
that position with a desired design surface.
• The difference is then displayed inside the
machine cab allowing the operator to easily and
efficiently determine what is required to create
the intended design on the ground.
Machine control, guidance,
automation – what’s the difference?
• Machine Control is the generic term used to
describe the technology as a whole.
• Machine Guidance refers to those systems that
only display the design difference to the operator.
• Machine Automation refers to systems that not
only show the operator the design difference but
are also able to directly control the machine
hydraulics to maintain a desired position.
How was machine control conceived?
• Machine control technologies are basically an
extension of traditional survey tools.
• Basic machine control devices were developed
in the 1970's with the invent of the Global
Positioning System or GPS. It wasn't until the
late 1990's when GPS reached its maturity
that machine control really started to be
utilized on construction machinery.
What is GPS?
• GPS (Global Positioning System) is a worldwide
satellite-based positioning system.
• Each satellite is able to send a radio signal back to
earth that can be received and processed to
determine a relatively accurate position.
• GPS receivers require an unobstructed sight to at
least 4 of the 24 functioning GPS satellites at any
one time in order to determine a position on the
ground.
What is GPS?
• The GPS network was created and is
maintained by the United States Department
of Defense.
• Initially developed as a military tool, the
satellite codes have been released to the
general public, making GPS positioning data
freely accessible to anyone with a GPS
receiver.
How does GPS work?
• Using GPS satellite positioning techniques is all
about measuring distances.
• Satellite signals travel at the speed of light and
the time taken to get to the receiver is measured
using extremely accurate atomic clocks.
• By intersecting the position range from at least 4
satellite signals, a receiver can calculate its known
position within an expected error.
• The more satellite ranges a receiver can process,
the less error in its position.
How does GPS work?
• There are additional causes of error when dealing
with satellite signals.
• Refraction (bending) of the satellite signals is
caused when travelling through the earth’s
atmosphere.
• Using satellite signals alone will result in a 30-60
feet accuracy. This amount of error is ok for your
average car or boat navigation system but is not
adequate for construction machinery systems.
How does GPS work?
• The errors caused by refraction can be adjusted with
the use of a GPS base station.
• A base station is a separate GPS receiver that is located
within or close to a construction site, mounted over a
point with known coordinates.
• The base station receives the same satellite errors as all
other receivers(boats, cars), but because it knows its
true position it is able to calculate the satellite signal
error and therefore determine what is required to
correct the satellite position data.
• The base station then transmits these corrections to all
other GPS devices in range.
How does GPS machine control work?
• GPS machine control systems use a combination
of satellite antennas, satellite signal receivers,
machine sensors, base station radio receiver and
cab-mounted displays when utilizing GPS satellite
guidance.
• The GPS antenna receives the satellite signals
which are decoded by the receiver.
• The machine control system processes all this
data constantly to produce the real-time position
of the machine’s GPS antenna.
How does GPS machine control work?
• The GPS antenna is mounted directly on to the
outside of the machine so as to maintain a
clear line of sight to the sky.
• The calculated position of the antenna is
transferred throughout the machine by a
combination of sensor readouts and complex
mathematical equations so as to determine
the exact position of the machines groundbreaking attachments.
How does GPS machine control work?
• The GPS display is mounted inside the machine cab.
• The display receives and processes all the information
from both the GPS receivers and the sensors to
calculate the machines current position.
• The display also contains the design information and
can compare the current and desired positions to
calculate a horizontal and vertical difference.
• The display processes all of this information at extreme
speeds to display the real-time cut/fill on its screen.
Machine Applications for AMG
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Motor Graders
Dozers
Hydraulic Hoes
Scrapers
Compactors
Pavers
Curb Machines
Milling Machines
File Types Created for Survey
and Machine Control
• Control files: Primary control points
• Line work file: Files containing 2D line work for
visual purposes only usually a DXF file
• Alignment Files
• Point files
• 3D surface model usually a TTM file
Benefits of AMG for the FDOT
• Increase in the project delivery time by
maximizing production during construction
progress.
• making construction more accurate and cost
effective.
• Increasing safety on the job site.
• Able to catch possible errors and inconsistencies
in design before construction.
• Having the ability to check Grade at any given
location instead of at specified cross section
distances.
Benefits of AMG for the Contractor
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Increased Productivity
Reduction in labor
Material savings
Safety
Reduction in survey cost
Increased Accuracy
Reduction in Fuel
Daily As-Builts
Federal Highway Administration
Statistics for AMG
• 66% savings for grade checking
• Up to 85% for reduction of stakes
• 3% to 6% by volume for improved material
yields.
• A savings of 4% to 6% of total project costs by
using 3D models.
• 15% to 25% increased efficiency in
earthmoving .
Why use machine control?
• Users are realizing productivity gains
• Less reliance for stakeout and grade checking is
resulting in reduced survey and earthworks costs.
• Eliminating guesswork is resulting in increased
accuracy
• Less re-works as well as material savings.
• The reduction of on the ground workers means
an improvement in workplace safety.
Dozer Application
Dozer
Excavator Application