Learning by Grading

Can you guess what this next sentence defines?  “The process of acquiring modifications in existing knowledge, skills, habits, or tendencies through experience, practice, or exercise.”  It is learning.  Learning seems easy enough.  Most of us learn things every day and, like our heartbeat, we hardly give it a second thought.  Most learning comes in the forms of bits and pieces of information that are automatically written to the hard drive that we call the brain. Some of these bits and pieces seem to float around in space. Like summertime bugs on a windshield, they adhere to a mind that decides the information is worth having.  Some types of learning come easily. Other types of learning are acquired at a substantial cost but worth that cost to the individual and their organization.  DISTek is a company that promotes and encourages employees to learn. Our classroom is the world.

When the opportunity presented itself, DISTek encouraged me to operate a brand new dozer in a Midwest quarry.  Although the opportunity was for an individual, the education did not end there.  That experience was homogenized into a 55 page PowerPoint that is shared with employees and customers alike.  By advancing continuing education of every prudent flavor, DISTek is ensuring that its employees will be the most knowledgeable and best trained in Off-Highway technology markets.  This collective experience is utilized every time a DISTek employee is assigned to a customer project. That employee is encouraged to discuss any challenges with peers.  While exercising the process of sharing ideas, the employee is exposed to ideas that may have otherwise never entered their mind.

Operating heavy equipment is not altogether new to me, so the mining company was not exactly throwing caution to the wind.  I happen to have been fortunate enough to be raised in an extended family of contractors, truck drivers and farmers.  Subsequently, I spent a fair amount of my growing up years on and around heavy equipment.  However, the Komatsu D155AX-6 dozer was the newest piece of machinery I have ever operated.

When approaching the machine for the first time, I thought that the design was easy on the eyes.  It’s no Z06 Corvette, but for a 50 ton machine of iron and steel, Komatsu did a nice job on the aesthetics.  Like most heavy equipment…it’s yellow.  I believe this is because “Caterpillar Yiller” cornered the market in the early years and the competitors played "follow the leader".  The main parts consist of a 360 horse power interim tier 4 engine, three speed automatic transmission with lockup torque converter, 12.3 yard Sigmadozer blade and a three shank ripper.  Komatsu claims the lockup converter and Sigmadozer blade increase production by 25% over the previous model.

Although the dozer is appealing to look upon, operation from the seat is the goal.  It didn’t take long to understand that the dozer was made for pushing and the quickest way to get it productive is by making slots.  Slots are trenches cut into the earth by making several cutting passes in the same track.  The slot walls force the material to remain in front of the blade which allows the operator to maximize machine capability.  The Sigmadozer blade design ensures that the material moves up the blade and rolls off the front, so the dozer blade is lifting as well as pushing.  When the load becomes large enough, the lockup torque converter unlocks and provides a gear ratio that can handle the load.  However; pushing material with the torque converter unlocked demands an increase in fuel consumption.  For the most part, I made it a goal to keep the converter locked up.  Komatsu’s 7 inch display of instant and trend power usage made it easy to predict when the converter was going to unlock and, therefore, easy to that situation from happening.  After a few hours you can tell by machine sound when the event was about to occur.

I learned that any attempt to steer by track while pushing material is not effective.  Turning by track causes the machine to slip and, when under heavy loads, the forward motion stops.  The dozer is most efficient when both tracks are pushing at the same speed. The ability to turn is accomplished by tilting the blade left or right.  Tilting the blade to turn requires trial and error; too much tilt and the machine slips or turns too much.  Too little tilt and the turn is ineffective which alters the outcome of the cut.  Moreover, turning with the blade requires the machine to slowly rotate around a point that is located to the absolute front of the machine.  There is a slight delay before determining if the result of the tilt is adequate.

As I mentioned before this dozer was fitted with a three shank ripper.  A ripper is an attachment that is mounted on the rear of the dozer.  When the ripper is lowered the hardened steel shanks slip into the hardpan earth and helps break it up.  The ripping action allows the next cut to require less stress and fuel.  Upon mastering cutting and turning, I turned my attention to the ripper.  It did not take long to find out that the ripper provided a substantial benefit over pushing alone.  First of all, the dozer pushes forward and rips in reverse. Since we need to be in reverse to get back to the start of our slot, we might as well spend that time ripping.  Ripping also required trial and error.  The secret is to rip at the correct depth.  Ripping too shallow is a waste of time, as it provides little profit to the next cutting since the hardpan remains unbroken.  Unlike a shallow rip, which does little to increase production, a rip that is too deep can be detrimental.  A deep rip can break up too much hardpan material and reduce traction on the next cut.  The rip depth should be just enough that on the next cut the cutting edge on the blade removes only the previously ripped material.

As much as I enjoyed the experience of learning to operate this machine, being an operator is not my occupation.  Or is it?  As a software engineer, the process of operating the machine afforded insight into what a software engineer can do to make the machine more efficient to the professional whose office is the cab of a dozer.  As an example, these are some of the items that as an operator I would like to see:

  • Add a ground speed sensor and hydraulics control for the purpose of slip control.
  • Auto blade shaker mode or quick drop blade for emptying blade on an incline or cleaning when material won’t scour.
  • Auto slow/stop before lift cylinders reach extended limit. This would prevent damage in a quick drop scenario.
  • A mode that moves steer by blade from blade joystick to steering joystick. Regardless of track or blade tilt you are still steering. The joystick should be the same.
  • Auto positioning of ripper when shifting into reverse. Use a position sensor and existing slope meter to auto adjust ripper depth as terrain changes.
  • Auto lifting of ripper when shifting into forward. Give the operator some more control with a depth pot also.
  • A mode that moves ripper control function from ripper joystick to blade control when shifting into reverse. Use existing joystick button to select between blade and ripper. Remove the ripper joystick completely.

As a software engineer, I am convinced that software can offer many cost effective functions that will improve the efficiency of most off-road machinery and; hopefully, the market share of those companies that choose to employ them.

Scott Estes
Former Senior Embedded Software Engineer
6612 Chancellor Drive, Ste. 600
Cedar Falls, IA 50613
Tel: 319-859-3600



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Staff Engineer

Technical Strengths:

Avionics mechanics, systems engineering

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BS-Software Engineering, AA-Electronics Engineering, Certified LabVIEW Architect, Certified Professional Instructor, LabVIEW Champion

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Avionics mechanics, systems engineering.

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At DISTek, I am part of a variety of different projects, which keeps me constantly learning and applying different practices to new challenges. In addition, I am part of complete processes, from architecting a new test system to implementing it and training customers on their new interface.

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