New Perspectives on Heavy metal

Jan. 1, 2005

If only the Moon had once had organic life, we might today be building roads on the Moon. The organic hydrocarbons of lunar life might have been converted—over geological time—to oil, the elixir of modern civilization. Black gold would certainly lure humans out of their planetary cocoon, and the U.S. would not have lost interest in space exploration after the Apollo missions.

If only the Moon had once had organic life, we might today be building roads on the Moon. The organic hydrocarbons of lunar life might have been converted—over geological time—to oil, the elixir of modern civilization. Black gold would certainly lure humans out of their planetary cocoon, and the U.S. would not have lost interest in space exploration after the Apollo missions.

Traffic might be light on L.R. 1 (Lunar Route 1), just a few commuters from the living center to the astrotelescope center or the drilling and mining center where computer-controlled excavators and scrapers dig in the lunar soil and gigantic, autonomous trucks carry loads of ore six times as big for the same weight on Earth.

Unfortunately, the Moon does not have oil or any other natural resources to entice colonization or even a visit in the past 30 years or so.

But there are plenty of “spacy” ideas right here on Earth to occupy designers of construction equipment. Caterpillar Inc. engineers make a habit of looking into the future to get an idea of what an industry will look like, decide what type of machine will be needed to accomplish that industry’s task and move their machines in that direction.

In a presentation titled “Tech Talk,” the Cat presenter tried to stimulate audience interest in predicting the future: “Why should you be concerned and interested in the future? Because you’re going to spend the rest of your life there.” Cat’s futuristic vision of an excavator includes tracks that extend and contract. The high idler rises above the roller frame and the front idler telescopes in to shorten the undercarriage for travel, tighter turning and better maneuverability. To create a more stable base for digging, the high idler lowers into the roller frame and the front idler telescopes out to lengthen the undercarriage.

The excavator of the future has a cab that sits inside the boom, where the operator has the best view of the bucket. On the other end of the boom, the counterweight is an integral part of the boom and moves up and down with the boom and the cab, helping raise the bucket.

Volvo Construction Equipment reinvented the excavator in a different way. They called their concept excavator SfinX. Instead of making the cab a part of the boom, Volvo made the cab free to move on its own. It can be moved up or outward to allow a good view of the work area for working in dangerous locations or even underwater.

“The cab being the operator’s workplace, we put no limits to our imagination,” said Lorenzo Terreno, vice president of product portfolio and advanced engineering at Volvo CE. “New concepts are continuously under investigation and put to the extreme. The cab could come down to the ground in the morning to greet the operator!”

Like Caterpillar, Volvo rethought the excavator’s tracks. Four track units allow the excavator to keep a much larger contact area with the ground than is possible with traditional twin tracks. Each track assembly has an independent suspension and can brake, turn and accelerate on its own. The tracks’ independent operation provides greater maneuverability and control.

Volvo also rethought the counterweight. Whereas Cat attached the counterweight to the boom, Volvo used extra space to create an “active counterweight” that moves in and out to compensate for the forces on the boom.

Warning: wide load

Another machine in Cat’s menagerie of the future is a giant motor grader, named the 55H for its 55-ft-wide blade. The front wheels steer. There is an articulation joint just ahead of the mobile track system.

Like Cat’s excavator of the future, the grader has its cab cut into the belly of the body of the machine where the operator has the best view of the blade.

As for the operation of these machines, Cat’s guiding principle is what it calls “simply complex.” The company expects the equipment to continue to get more complex in its components but more simple in its operator interface. Enabling complex components is the transition to electronic operation of just about everything. Electronics control the hydraulics. Electronics control the mechanical components. And electronics control the pneumatic components. And if the operator only has to operate the electronics instead of operating the hydraulics, then the controls can have as much flexibility as the designer’s imagination or the operator’s preference.

A good example of simple complexity is Cat’s Aggregate Autodig system, now available on several of the company’s wheel loaders. With Aggregate Autodig, all the operator needs to do is point the loader toward the pile with the bucket on the ground and press the accelerator. The loader will move forward until it makes contact with the pile, then it will automatically load the bucket. The only time the operator needs to touch the implement controls during the cycle is to dump the bucket.

With Aggregate Autodig, a novice operator can consistently fill the bucket and be nearly as productive as an experienced operator.

And how does the loader know when it is into the pile? Sensors, sensors, sensors.

Manufacturers are adding sensors to machines to make the operator’s job easier, because the machine knows exactly where it is and what it is supposed to be doing, and also to make the mechanic’s job easier.

Your dozer is calling

The most radical transformation of the work site might not be in the machines themselves. Actually, it is part of the individual pieces of equipment but it has more to do with coordinating the equipment on a jobsite.

Communication units will tell future construction equipment exactly where it is by talking to Global Positioning System (GPS) satellites. By recording data and then talking to mobile computers, the machines can tell onsite personnel how they are functioning, whether they have a pain in the transmission, for instance. The machine’s onboard brain will gather the functional data from sensors placed throughout the machine.

Caterpillar has a system in production called the Vital Information Management System (VIMS). By talking to the mechanic, whether onsite or at any other location in the world, VIMS can report on its major machine functions and trends in them. VIMS can send warnings when some function is out of its operating specifications.

Cat also has experimented with computer-controlled machines such as mining trucks that could maneuver around a mine site without a driver. The truck could navigate using GPS, detect obstacles using radar, even schedule its own maintenance.

These concepts may never appear on a production model, but the exercise of rethinking something, no matter what it is, is invigorating and may yield an idea that will revolutionize the industry.

A few innovations that have made their way onto production models are discussed below.

Paver transfer

Some innovations come about simply by combining two things that seem to go together naturally. The Asphalt Mobile Equipment Group of Terex Roadbuilding has combined an asphalt remix paver and a material transfer vehicle and made the Remix Anti-Segregation System paver (Circle 916). The machine nearly eliminates thermal and material segregation while it offers noncontact paving, continuous paving, a high-capacity receiving hopper and offset paving. The machine’s receiving hopper includes counter-rotating augers that reblend material. It can be used as a transfer device on every lift of new road construction, even the most critical first lift over sub-base material.

Measuring tilt

The SiteVision GPS system (Circle 917) from Trimble Navigation Ltd., Sunnyvale, Calif., now is available for excavators with tilting buckets. The system uses dual GPS antennas to compute the position of a tilt-bucket attachment on an excavator when working on jobs involving digging to a slope, such as a trench. Sensor output is used to calculate an accurate 3-D position and orientation. An onboard computer compares the position and orientation to a design and computes the cut or fill to grade.

Tack and pave

The SP-200 is Roadtec Inc.’s combination spray paver. Designed for traditional paving and NovaChip applications, the SP-200 (Circle 918) incorporates a spray bar in front of the material augers. The spray is a necessity for NovaChip and eliminates the need for a tack truck. The SP-200 when used in conventional paving operations makes for a much cleaner jobsite, since machines no longer have to travel through the applied tack. Also the paving train is considerably shorter without a tack truck. The SP-200 will be available for purchase in spring 2005 and on display at ConExpo-Con/Agg in Las Vegas.