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Komatsu D61EXi-23 Dozer


Crawler Dozers

With the new D61i-23 crawler dozers, Komatsu, in collaboration with Topcon, has introduced a new automated blade-control system, Intelligent Machine Control, which represents a significant advance in this evolving technology. The innovative engineering behind Komatsu’s new system involves two major aspects: repackaging system components and making the machine intelligent enough to use the automated system from the first rough-cut pass to the final finishing pass. The result, says Komatsu, is a significant productivity increase for both experienced and less-experienced operators.

Innovative repackaging

First, the company has integrated all the external hardware of a typical aftermarket automated blade-control system into the base machine. Gone are the blade-mounted GNSS (Global Navigation Satellite System) antenna (with its mast, cables and brackets), as well as blade-mounted orientation sensors.

All that hardware and its capability is now neatly packaged into a roof-mounted antenna (a cube about 4 inches square), into a new chassis-mounted Enhanced Inertia Measurement Unit (which determines machine orientation 100 times per second), and into new Komatsu-designed, stroke-sensing hydraulic cylinders (raise, tilt and angle) that precisely report blade position.

“Integrating this hardware into the machine might sound relatively simple,” says Peter Robson, Komatsu’s director of intelligent machine controls, “but it’s very, very difficult, for example, to take the antenna off the blade and move it back to the roof top and still maintain the accuracy of a blade-mounted antenna. Our goal was to introduce the new system with the same accuracy of an aftermarket system—otherwise we wouldn’t have met the customer’s expectations.”

Integrating the hardware, says Robson, has a number of advantages. By placing the antenna on the roof, he says, “as-built” information (the present contour of the site) can be accurately measured at the track shoes, no matter the actual location of the blade.  With the collection of accurate as-built data, he says, dozing progress can be clearly transferred to the operator in real time via selectable settings, further improving overall efficiency.

Other advantages, says Robson, include eliminating the vulnerable cables (and connections) between the blade and machine, and eliminating the need for climbing on the blade to remove the antenna at night to protect against theft and vandalism.

The rest of the story

Hardware integration is only part of the innovative technology involved with Komatsu’s new machine-control system. The “i” in the D61i-23 is for “intelligence,” says Komatsu, and refers to the system’s capability to automatically control the dozing process from start to finish.

With a convention automated blade-control system, says Komatsu, the operator typically shuts off the system and dozes with manual control until approaching finish grade, then switches on the system. If the system were switched on and the finished grade were at an unattainable depth in terms of the machine being able to remove that much material in a pass, the tractor would likely stall or slip the tracks. The alternative would be to manually program in progressive offsets (digitally altering the depth of the final grade) to make the tractor work in small bites.

What Komatsu has done, essentially, is design the blade-control system, operating in its automatic mode, to sense the load on the blade, and then to react to a given resistance by elevating the blade slightly and tweaking the hydrostatic drive system to keep the load moving without track slip.

“The machine is so intelligent,” says Robson, “that as it’s dozing along and realizes that the blade is nearing an optimum load, and that pressures are getting to the point that the tracks will break away and slip, it says, in effect, I’m going to maintain forward movement without tearing up the ground and wearing out the undercarriage. It does that in rough cutting by raising the blade automatically to reduce the load and to reduce the possibility of track slip. This process was left to operator experience previously.

“This is where the real intelligence of the new machine-control system resides. The net result is that system will operate in its automatic mode from the first pass at the top of the existing elevation to the last pass at finish grade, assisting the operator to cut all the way down to the target design surface. An aftermarket system typically is used to cut only the final few tenths [of a foot].

Also, if the site plan changes during construction, the new Komatsu system can receive changes to the digital site map wirelessly, eliminating the need to dispatch personnel to the site to update the machine’s onboard map.

Controlling the system

Another intelligent aspect of Komatsu’s new system is the inclusion of dozing modes— cut-and-carry, heavy-cut, spreading, and grading. The cut-and-carry mode, says Komatsu, accommodates the technique that most operators employ, that is, starting at the beginning of the cut and pushing all the way to the end of the proposed cut. In this mode, the D61i-23 will optimally load its blade, and then elevate the blade slightly to a carry position.

The heavy-cut mode would be used primarily, says Jason Anetsberger, product-marketing manager for intelligent machine controls, when operators prefer to start the cut a few machine lengths from the end, then to progressively reverse to the start of the cut, taking short, aggressive passes in the process. The spreading mode, he says, might be used for precisely placing base aggregate, and the grading mode reacts essentially as would a conventional aftermarket blade-control system.

“The system has control logic for determining how the blade loads and how the tracks react in different operating situations,” says Anetsberger, “which allows the system to be customized to how the operator likes to run the machine.”

In addition, the new machine-control system incorporates load modes—light, normal, and heavy—which are akin, says Robson, to the work modes available on most excavators today. The load modes, he says, allow the system to be further “optimized” for the application.

Experiencing the system

At a media event to introduce the new machine-control system, Komatsu encouraged members of the press to try the new hardware. The system is extremely operator-friendly, requiring only a slight tap forward on the blade lever when the system is in “auto” to initiate a dozing pass. The operator, via a full-color monitor, also can select how aggressively the machine initiates the cut.

For the less experienced, easing more gently into the cut seemed the best approach, and in the load-and-carry mode, the blade either digs in until it reaches the design surface, or until it reaches an optimum load. As Komatsu had explained, when the machine reaches a certain threshold of resistance, the blade lifts slightly and the machine pushes easily to the end of the cut without a hint of track spin. At the end of the cut, tap the blade lever slightly rearward, and the blade lifts to pre-set height for reverse travel. Nice for a rookie operator at last to be able to reverse over a just-made cut that’s flat and smooth and doesn’t jolt the tractor over a washboard surface. 

In the heavy-cut mode, when employing the progressive-reverse technique, you sense that the machine is reacting more aggressively, but it still controls the depth of cut to keep moving. Switching modes, say from cut-and-carry to spreading, is easy even for the rookie, requiring only tapping an icon on the monitor to set the desired mode. The machine demonstrated its ability to evenly spread material, when, coming up on the far side of a sizeable spoil pile, it pushed strongly through the pile and placed the material in an even layer along the path of the cut.

D61i-23 and the future

Topcon representatives at the media event were on hand to explain the benefits of Topcon’s new Enterprise3D system, which seems to dovetail with the expanded capabilities of the “i” versions of the new D61-23. As Topcon explained, Enterprise3D is a construction- and engineering-management tool that facilitates complete jobsite planning, scheduling and reporting via Topcon’s new web portal.

Included in the system’s capabilities, as we understand the system (available late summer) is the ability to report as-built and production data in real time via computer, tablet or smart phone. The system has the ability, says Topcon, to calculate the volume of material moved, calculate the differences between planned and actual volumes, and then send this information in summarized form to the site manager.

Regarding the new Komatsu tractors, non-“i” models will remain available, and the incorporating the new Intelligent Machine Control system, says the company, will in no way affect the “i” version’s ability or reputation as an excellent grading machine. The new “i” version is available in a long-track-on-ground model (D61EXi-23) and a low-ground-pressure model (D61PXi-23). Operating weights for the 168-horsepower machines range from approximately 39,500 to 41,500 pounds.


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