By his own admission, Roger Croft is not easily impressed with most of the new machine control products that come out for today’s construction professional.  The veteran sales technician from equipment supplier Lengemann of Florida says he has seen products come and go, and often the end-result falls far short of the promises made by the manufacturers.  In recent years, however, he has seen such products become increasingly sophisticated — better able to cope with and adapt to changing site conditions.  As a result, he knew the day was coming when the machine operator’s demand for control at high speeds could finally meet the surveyor’s demands for onsite accuracy.  On a highway project headed up by Ocala, Fla.-based Steven Counts Inc. (SCI), Croft says he’s seen the future of machine control and believes its name is Topcon’s 3D-MC².

The Need for Speed
As one of the largest heavy highway contractors in all of central Florida, SCI maintains an impressive equipment fleet and works hard to keep its competitive edge. According to Chuck Counts, SCI’s Survey Department Head, it does so by, among other things, staying abreast of new equipment changes and improvements which it feels can help save time, improve performance and raise efficiency.

“Machine control has been an accepted part of our operation since 2002, and its purchase was driven by our belief that this was where construction was headed.  We were confident that this new technology could get us ahead in production and make us a company that customers would want to rely upon.  That’s proven to be true and, as a result, we now have 3D machine control on many of our dozers, graders, and paddle pans.”

That addition alone, says Counts — by nature of not overdigging or undercutting, and eliminating the need for staking the site — has afforded them an increase in production of anywhere from 25% to 50%, depending on the project.  Yet, despite these gains, he says his operators could often still be heard complaining that they could not work at the speeds to which they’d become accustomed. 

“So, when we were told by Roger Croft at Lengemann that Topcon was testing a new machine control — one that would allow us to double the speed at which we can grade, we wanted to be a part of those tests.  The highway 484 project, specifically construction of a series of retention ponds adjacent to that highway, was an ideal proving ground for us.”

This is Ground Control...
At the heart of the new 3D-MC² system is an inertial sensor which overcomes many of the shortcomings commonly associated with machine control, says Brian Lingobardo, Topcon’s Product Manager for its 3D Machine Control Products.

“Previous generation machine control systems rely upon a slope sensor which gets its readings from a level vial.  This vial had to be dampened to prevent it from being over-reactive and cause instability in the machine.  While effective, this technology hindered the overall speed capability of previous 3D machine systems.  Because of these limitations, a new advanced system was needed to allow grading at most any speed.”

Topcon’s answer to that demand was the 3D-MC² system.  The system’s sensor updates the previous technology and instead relies upon accelerometers and gyroscopes to measure blade position.  Because all measurements are being taken electronically, the system presents a far more accurate indication.

“In addition to that,” says Lingobardo, “the controller, in this case, Topcon’s MC-R3, is receiving information from the sensor which is updating at a rate of 100 times per second.  This allows it to constantly know both the blade position and how to correct accordingly, allowing the operator to make corrections on the fly.

Proven at Work
What all this means in real-time output is a dramatic uptick in both productivity and quality.  At SCI’s Highway 484 widening project, a single dozer has been working alongside a pair of 40-ton articulated dumps and, despite being outsized and outnumbered, has been holding its own nicely, according to Counts.

“This is one of the larger of nine retention ponds we built alongside the 484 project,” he says. “In fact, in an earlier phase of the job, we actually excavated more than 37,000 cu. yds. of sand from that pond to use it for sub-grade on the road.  Because of the porous lime rock under the sand, however, heavy rains have a tendency to create cavities or sinkholes.  So, to alleviate that, and assist with percolation, the engineers had us overexcavate, lay down a filter fabric, then place a sand layer over it.”

It was during the replacement of the sand layer that Counts says they truly saw the strengths of the new control system at work.

“With today’s economy as tight as it is, being able to get things done with fewer personnel and pieces of equipment is a huge plus.  If we weren’t running the new machine control system, we would probably have had three dozers working with those trucks to spread this dirt.  Instead, we had a single John Deere 650 — a smaller dozer than would typically be used on a job like this — and he was easily keeping up with them.  Our operator, Scott Parrish, says that for most of the project, he’s had the throttle of the hydrostatic drive set at between 2.5 and 3.0; to me, that’s outstanding.  Since we’ve been testing the 3D-MC² we’ve pretty much doubled the production from that one dozer. Couple that with the fact that we are also seeing a savings by having a “stakeless” job and the benefits are pretty impressive.

Smooth Operator
While time is, as they say, of the essence, Parrish, SCI’s operator is equally quick to say he’s been impressed with the level of control he’s gotten with the new system.

“On a job in which we are working over a fabric barrier, there are always concerns about accidentally digging down too deep and catching and tearing that fabric.  Here, we were able to set our grade in automatic and not have to worry about that at all; that’s how smooth and steady the system is.  As I make each pass there are virtually no windrows to speak of and, even when encountering a huge pile, I can plow through it without any feeling that it’s getting drawn down into the pile.  The reaction times are so outstanding that this could be, at times, a hands-free operation.” 

That ability to free the operator’s hands from the tedium of constantly adjusting blade height and pitch, can enhance onsite safety as well, says Lengemann’s Croft.