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Introduction to the Basics of the Komatsu/Topcon Sonic and Laser MachineControl System for Grading

PRODUCT BULLETIN

Basics ofKomatsu/Topcon 2D Machine ControlINTERNAL USE ONLY

TABLE OF CONTENTS

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1 What Is Machine Control?Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2Supply & Demand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2 Conventional MethodsOverview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3The Grader Setter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Manual Cross-Slope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4Labor Intensive Finished Grade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3 Machine Control ComponentsTwo Basic Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6Automatic Machine Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7Control Box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Grade Reference Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4 Sonic—Controlling At The Speed Of SoundHydraulic Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9The Sonic Tracker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-10The Working Window . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-14

5 Sonic—Putting It To WorkPositioning the Sonic Tracker . . . . . . . . . . . . . . . . . . . . . . . . . . . 15-18

6 Topcon Laser ControlObjective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Sloping Plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Topcon Lasers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20The Receivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21The Mast . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

7 Using Laser ControlObjective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Setting Up the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22-23Job Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24-25Manual Grade Alignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

8 Slope ControlObjective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27Blade Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27-28The Slope Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29The Rotation Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30The Mainfall Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

1 WHAT IS MACHINE CONTROL?

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OBJECTIVE

SUPPLY & DEMAND

This Product Bulletin explains how the Komatsu/Topcon machine control system is used to increaseproductivity and improve the quality of finish grading.Specifically, you will begin to understand how theKomatsu/Topcon system helps grading contractors:

• increase grading efficiency and production• control material usage• reduce engineering costs

All of which result in a much more profitable and sat-isfying job for the contractor.

The bulletin will focus on how the Topcon systemoperates to automatically control the elevation andcross slope of a Komatsu motor grader or dozerblade.

What is construction machine control and why is itrapidly becoming so popular with contractors world-wide? The basic reasons are supply and demand.The demand for new construction is ever increasing.New roads, new buildings, new homes… the demandand the schedule far exceeds the capacity of theconstruction industry in many areas.

That problem is complicated by the fact that experi-enced equipment operators are in very short supply,meaning less knowledgeable operators are beingrequired to meet tightening specifications and dead-lines.

Add the fact that equipment and material costs arealso rising, and you get a feeling for what most con-tractors are faced with every day. They are lookingfor the help machine control offers.

Machine control offers contractors a way to meetdeadlines by improving productivity through automa-tion. What other industries learned years ago, theconstruction industry is just now waking up to—automation is required to be a profitable manufactur-er. What’s the largest manufacturing industry in theworld? Construction. It’s also the least automated.How big is the sales opportunity for machine control?It’s huge, it’s just starting to develop, and you’re rep-resenting the recognized leader in machine controltechnology.

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CONVENTIONAL METHODSOVERVIEW

THE GRADE SETTER

To better appreciate the benefits of automated gradecontrol you need an understanding of traditionalgrade control methods.

Until machine control entered the picture, basicmethods of controlling grading had changed very lit-tle. In fact, the methods traditionally used today arealmost identical to the methods used when gradingequipment was horse drawn. Even though gradingequipment has vastly improved, their productivity isstill dependent on manual methods of grade check-ing—all of which are very slow and labor-intensive.

The most common method for rough grade control isto have a person called a grade setter (also called agrade checker) assigned to the grading equipment.He serves two functions:

• Determine the location of finished grade, letting the operator know the amount of cut or fillneeded to achieve it

• Let the operator know when finished grade is achieved

The grade setter will usually use a hand level tocheck grade at each station. Typically, before thegrading begins, the grade setting crew will make ahike-up mark on the guard stake at each station.The mark is always made a specified distance abovefinished grade for that station. To determine grade onthe road, the grade setter will look through the handlevel at the corresponding guard stake, then refer-ence a rule or small grade rod to determine whetherand how much that area needs to be cut or filled. Ifthe grade is too high, he’ll signal the operator that acut is needed at that location. If the grade is too low,he’ll signal a fill is needed.

Rather than using a hand level, a grade setting crewis sometimes used. One person holds a stringline aknown distance above a station. The other pulls thestringline over the area to be graded, keeping thestringline level. The grade setter then measures fromthe string to the ground, calculates the proper cut orfill and paints it on the ground.

This allows the grade information to be posted aheadof the grader, but once the grade is cut, the paint isgone, so a grade setting crew is still needed to verifythe grade is correct or paint new grade information.The motor grader has to stop and wait while newchecks are made. This routine is repeated until roughgrade is obtained.

It’s easy to understand how this manual gradechecking method is real drag on productivity, not tomention how important it is for the operator to beexperienced in order to interpret and utilize the vaguegrade information that’s supplied to him.

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2 CONVENTIONAL METHODS

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On a road job, cross slope is also required. Duringrough grading the operator usually has to guess atmaintaining the correct cross slope since the gradesetter is only providing elevation information.Consequently, slope is usually left a little high on pur-pose to prevent undercutting.

A slope meter is sometimes used to help the opera-tor manually check cross slope as he grades. Theslope meter is frequently mounted in the cab, dis-playing the slope of the cab as it travels over the justgraded pass. The slope meter can also be mountedto the blade, allowing the operator to try to manuallycontrol the slope as it grades.

After the edge is cut to grade, the grade setter andmotor grader will move toward the crown and con-tinue rough grading. This movement is almost alwaysno more than one-half a blade width. Since the slopeis left a little high intentionally, moving over an entireblade width would cause a noticeable gain in crossslope. By moving only half the width, greater accura-cy is maintained, but productivity is also cut in half.

MANUAL CROSS-SLOPE

CROSS SLOPE

1st Pass 2nd Pass

Duplicate Grading

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2CONVENTIONAL METHODS

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LABOR-INTENSIVE FINISHED GRADE

As a finished grade reference, usually after anyrequired base material is spread, blue tops (orguineas) are placed to give the operator accurategrade information.

Depending on the job, the blue tops will be placed bya three- or four-person crew pulling a stringline fromhub to hub as previously described. Many times thisfunction is performed by a third-party engineeringcrew hired by the grading contractor, supplied by thedeveloper or, in the case of most highways, suppliedby the state. Stake chasers are put on top of eachblue top so it can be located as the base material fre-quently covers them. A person called a guinea hop-per, usually the grade checker, walks ahead of thegrader, uncovering blue tops so the operator can seethem.

It’s easy to understand that conventional grade controlmethods are slow, labor intensive and depend on anexperienced operator for accurate grade finishing.

• Slow• Labor intensive• Require experienced operators

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3 MACHINE CONTROL COMPONENTS

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TWO BASIC TYPES

There are two basic types of machine control systems:

• Manual systems, usually called indicate systems• Automatic systems

A manual machine control system provides the oper-ator with visual grade information that he monitorsand manually adjusts the elevation of the bladeaccordingly. Manual systems are simple to use andprovide a big improvement over conventional gradecontrol methods. Manual systems are more commonon bulldozers and scrapers, where productive roughgrading is the objective.

For fine grading, automatic control is the answer.Automatic machine control systems provide theoperator with visual grade information and give himthe option of sending that information straight to thehydraulic system of the equipment, automaticallymaintaining the blade on-grade.

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3MACHINE CONTROL COMPONENTS

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AUTOMATIC MACHINECONTROL

Automatic machine control systems are composed offour primary components that work together to pro-vide smooth, precise grading:

• grade reference sensor

• gravitational and rotational sensors

• control box

• hydraulic interface

We’ll discuss the grade reference sensor in detail inthe next few pages. Briefly, it monitors a known gradereference to supply the system with the information itneeds to determine a precise on-grade location at alltimes.

Gravitational and rotational sensors are passive sen-sors that monitor the physical orientation of the cuttingedge of the equipment so the grade information canbe utilized to properly position the blade on-grade.

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Remote “Smart” Switch“High Flow” Hydraulics

Sonic Tracker IITM

Rotation Sensor

System FiveControl Box

Slope Sensor

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3 MACHINE CONTROL COMPONENTS

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CONTROL BOX

GRADE REFERENCESENSOR

The grade reference sensor is the primary compo-nent that provides an immediate and easy way todemonstrate the advantages of automatic grade con-trol. Why? Because it eliminates the need for thegrade setter. Remember him? The person or crewwho manually communicated grade information tothe operator.

So just what is a grade reference sensor? As wesaid earlier, it’s a device that monitors a known gradereference to supply the system with the information itneeds to determine a precise on-grade location at alltimes. Topcon grade control systems can beequipped with four different types of grade referencesensors—sonic sensors, laser sensors, LPS receiversand GPS receivers.

Sonic and laser sensors are the most widely usedand are the backbone of most automatic grade con-trol systems being sold today. GPS and LPSreceivers are an integral component of the newlydeveloping three-dimensional, digital grade controlsystems that allow rough and fine grading to be con-trolled straight from the engineering plan data. It’s avery exciting and fast developing technology thatTopcon is pioneering. But the best way for you to beprepared for digital grade control is to understandautomatic grade control using sonic and laser sen-sors.

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The control box serves two functions. It provides theoperator the ability to enter and monitor specific ele-vation and cross-slope data necessary for the currentgrading application, and it’s the central point whereinformation from the grade reference, gravitationaland rotational sensors meet and are processedbefore being sent to the hydraulic system.

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4SONIC—CONTROLLING AT THESPEED OF SOUND

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HYDRAULIC INTERFACE

The hydraulic interface reads the grade adjustmentsignal from the control box and then automaticallyoperates the hydraulic functions of the grader tomaintain the blade at the desired grade.

On Komatsu graders an additional 2 spool valve ismounted to the top of the front frame. This valve isplumbed in parallel with the grader’s blade lift circuit.In the automatic mode, the control box sends agrade adjustment electrical signal to the electric ser-vos mounted on the valve. The servos actuate thehydraulic spools which meter oil to and from the liftcylinders to maintain the blade at the desired grade.

THE SONIC TRACKER

The Sonic Tracker uses sound waves to locate andmonitor a physical grade reference. These referencescan include almost anything, but are usually a string-line, a curb or a previously graded or paved surface.The Sonic Tracker enables a contractor to use auto-matic grade control while continuing to use a tradi-tional grade reference.

Grading contractors are familiar with setting up astringline to mark grades and they commonly gradeto match the location of a curb or a previous gradingpass.

With the Sonic Tracker, grading productivity andaccuracy is improved because a grade setter is nolonger needed. The grade setter is transformed into atrue grade checker; simply following along behind thegrader, checking to make sure the grade is being cutcorrectly. Now the grading equipment is determiningproductivity, not the grade setter.

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4 SONIC—CONTROLLING AT THESPEED OF SOUND

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SONIC TRACKER continued

The Sonic Tracker emits and monitors a constantstream of high frequency sound waves—39 pulsesper second.

As the sound waves travel away from the SonicTracker, they become wider, forming a cone shape.The width of the cone is called the sonic footprint.Closer to the Sonic Tracker, the footprint is smaller,further away from the Sonic Tracker, the footprint iswider. The Sonic Tracker can only detect surfaceswithin the sonic footprint.

As each sound wave leaves the Sonic Tracker (image19), an internal timer is started that measures theamount of time it takes for that wave to return.Knowing the speed of sound, the Sonic Tracker caneasily calculate the distance the wave traveled until itencountered a surface that caused it to reflect. Bymounting the Sonic Tracker to the blade and keepingit over the grade reference, it supplies the grade con-trol system with continuous information that can beused to keep the blade on grade.

Sounds simple, right? It is, but as usual there arealways factors that must be considered. Like whathappens if the Sonic Tracker loses the grade refer-ence, or it passes over the grade pins that hold thestringline? That’s where the working window comesinto play.

Sound wave isemitted.Timer starts.

Sound wavereflects off ofgrade reference.

Returns to SonicTracker.Timer stops.

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THE WORKING WINDOW

The working window is a distance two-tenths of afoot (2.4 inches or 6 centimeters) above and belowthe grade reference. The Sonic Tracker will only rec-ognize and interpret sound waves that are reflectedfrom a surface inside the working window. So when asound wave returns too early or too late, it’s ignored.

The working window can be positioned anywherewithin the operating range of the Sonic Tracker,which is from 14 to 55 inches below the SonicTracker.

As the grading equipment is being set up for auto-matic grade control, the operator will set the blade toa known grade elevation while positioning the SonicTracker over the grade reference. He’ll then use thecontrol box to tell the system the reflected signalbeing received by the Sonic Tracker is the on-gradeposition. This is now the center of the working win-dow.

The working window itself is divided into three dis-tinct zones (image 22), on-grade, above grade andbelow grade. Visual indicators are displayed on boththe control box and the face of the Sonic Tracker thatshow the relative grade position of the blade.

When the blade is in the on-grade zone, a solid lineappears (image 23). In automatic operation, the on-grade zone is only one-hundredth of a foot wide(±1/6 of an inch or ±1.5 millimeters). Visually, the on-grade zone is three-hundredths of a foot (±3/32 of aninch or ±3 millimeters). The reason for the differenceis one-hundredth is simply too tight for visual control,although it’s well within the proportional hydrauliccontrol capabilities of Topcon’s hydraulic interface.

That means in automatic operation the on-gradeaccuracy of the Sonic Tracker is plus or minus five-thousandths of a foot, a mere sixteenth of inch orone-and-a-half millimeters. Try beating that with agrade setter.

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THE WORKING WINDOW continued

The above grade zone and below grade zone aretwo-tenths of a foot each (2.4 inches or 6 centime-ters). The above and below grade zones are sub-divided into two areas that are displayed by either aflashing arrow or a solid arrow.

When the Sonic Tracker receives a signal that is out-side the on-grade zone but is within five-hundredthsof a foot of the grade reference, a flashing arrowappears on the control box and on the Sonic Tracker.

A flashing down arrow (image 24) means the SonicTracker (and blade) are slightly above grade.

A flashing up arrow (image 25) means the SonicTracker (and blade) are slightly below grade.

If the Sonic Tracker moves further off grade, up totwo-tenths of a foot, the arrow will be solid. A soliddown arrow (image 26) means the Sonic Tracker andblade are from five-hundredths to two-tenths of afoot above grade.

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A solid up arrow (image 27) means the Sonic Trackerand blade are from five-hundredths to two-tenths ofa foot below grade.

If the Sonic Tracker moves out of the working win-dow, the display goes dark, then the arrow beginsslowly blinking, indicating the Sonic Tracker andblade are more than two-tenths of a foot above(down arrow) or below (up arrow) grade (image 28).

So, if the blade starts to rise, causing the SonicTracker to become further away from the grade refer-ence, it will take longer for the reflected sound wavesto return to the Sonic Tracker. The Sonic Tracker willsend the appropriate signal to the control box, dis-playing a visual above-grade indication to the opera-tor and if automatic control is enabled, the controlbox will transmit correction information to thehydraulic interface to automatically bring the bladedown to grade (image 29).

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If the blade starts to get too low, causing the SonicTracker to become closer to the grade reference, thereflected sound waves return to the Sonic Trackerfaster. The Sonic Tracker will send the appropriatesignal to the control box, displaying a visual below-grade indication to the operator and if automaticcontrol is enabled, the control box will transmit cor-rection information to the hydraulic interface to auto-matically bring the blade up to grade (image 30).

If the Sonic Tracker loses the grade reference, thereflected sound waves return to the Sonic Trackermuch slower. The signal is no longer within the work-ing window. The control box indicates the conditionwith a slowly blinking arrow and no grade correctionsignal is sent to the hydraulic interface until the sig-nal is once again received from within the workingwindow (image 31).

If the Sonic Tracker detects an obstruction above thegrade reference, the sound waves return to the SonicTracker very quickly. The signal is no longer withinthe working window and no grade correction signal issent to the hydraulic interface (image 32). This iswhat happens when the Sonic Tracker passes over agrade pin.

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5SONIC—PUTTING IT TO WORK

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POSITIONING THESONIC TRACKER

Now that you know how the Sonic Tracker operates,it will be easier to understand how to position it formaximum grading efficiency using a variety of gradereferences.

The working window of the Sonic Tracker can beelectronically positioned anywhere from 14 inches (35centimeters) to 55 inches (140 centimeters) from thebase of the Sonic Tracker.

If the working window is set very close to the SonicTracker, the sonic footprint will be narrow and itcould be difficult for the operator to maintain theSonic Tracker over some grade references, such as astringline (image 34).

If the working window is set too far from the SonicTracker, the sonic footprint will become larger, mak-ing it easier for the system to detect reflection fromobjects that may be in the working window but notpart of the grade reference, such as the edge of themoldboard (image 35) or the top lip of a curb.

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5 SONIC—PUTTING IT TO WORK

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POSITIONING THE SONIC TRACKER continued

So it’s always a good idea to position the SonicTracker about 24 inches (61 centimeters) above thegrade reference (image 36). This provides a sonicfootprint that’s roughly six inches (15 centimeters)wide. Wide enough for most operators to maintain itover the grade reference with relative ease, but notso wide that false echoes should be a concern.

The Sonic Tracker can be manually positioned on itsL-bar Bracket so it’s about 24 inches above thedesired grade reference.

To initially set up the Sonic Tracker, manually placethe blade so it’s just barely resting on the ground.Make sure both sides of the blade are resting onsmooth ground. This is important to eliminate anypossibility of referencing only the worn edge of ablade.

Now set the Tracker to on-grade using the controlbox or SmartSwitch buttons (image 38). This sendsthe working window down to the ground with thecurrent reflected signal being interpreted as on-grade.

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5SONIC—PUTTING IT TO WORK

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To set the LCD on the control box to read 0.00, turnthe display knob in the upper panel to Zero and pushthe enter button. Now the Sonic Tracker is set to thesame elevation as the cutting edge. This is called zeroing out the Sonic Tracker.

Once the Sonic Tracker has been zeroed out, theoperator can dial in a desired elevation above orbelow the grade reference.

The job shown at the right (image 40) has a one-footvertical cut from the existing surface. The operatordials in negative 1.00 and begins cutting. The work-ing window moves up exactly one foot. The arrowswill visually guide the operator to grade, and whenhe’s close to the desired cut, he’ll switch to automat-ic operation to let the system precisely finish the cut.

The Sonic Tracker is ideal for tracking an elevatedstringline. For a new road, a stringline is a great wayto set grade. On the job shown at the right (image41), the stringline was set at a two-foot hike-up, ortwo feet above finished grade.

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5 SONIC—PUTTING IT TO WORK

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After zeroing out the blade as described earlier, allthe operator has to do is position the Sonic Trackerover the stringline and dial in negative 2.00 in thecontrol box. The working window moves up exactlytwo feet above the cutting edge, so the systemknows that finished grade is now two feet below thestringline.

If half-a-foot of base material was being placed ontop of the cut, the operator would simply change thesetting to negative 1.50 after grade was cut thentrack the same stringline to finish the base—exactlysix inches, half a foot, deep on top of the cut. Itdoesn’t get much easier, faster or more accuratethan that. 42

6TOPCON LASER CONTROL

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OBJECTIVE

When the grading application is a flat plane, using alaser sensor instead of a Sonic Tracker to receivegrade information from a rotating laser beam is anextremely easy, fast and accurate method of provid-ing grade control.

Most contractors are familiar with laser control fromits standard use as one-man leveling crew. Using alaser for automatic grade control is no different,except the laser sensor is mounted to the gradingequipment and it’s capable of receiving the beamfrom any direction. This is called 360-degree recep-tion.

As the sensor receives the laser beam, it sends gradeinformation—above, below or on-grade (image 44)—to the control box for visual grade monitoring and tothe hydraulic interface when operating automatically,just like the Sonic Tracker.

With the Laser Tracker, there are no stringlines to setup and no previous passes to match, just continuousgrade control being provided over the entire job by arotating laser beam. So why isn’t laser control usedall the time?

Because the laser beam is perfectly flat and mostgrading jobs aren’t. Highways certainly aren’t flat.They roll over hills and bank around curves. Parkinglots may have some flat areas, but they have chang-ing slopes to allow for proper drainage and to matchthe terrain.

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6 TOPCON LASER CONTROL

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SLOPING PLANE

Laser control is limited to jobs that require a flat, orplanar, surface. Sometimes the finished grade will belevel, like a building pad. Other times the plane willbe sloped in either one-direction, a single slope, orin two directions, called a dual slope. Dual slope isalso sometimes referred to as compound slope. Anairport runway could be an example of a grading jobthat could be either a single or a dual slope. If therunway itself was level, a single cross-slope would benecessary to form a slight crown for drainage. If therunway was designed with a slight slope, the crownwould require an additional cross-slope, creating adual slope plane.

Rotating lasers are available from Topcon that arelevel only, single-slope and dual-slope capable.Current level only models include the RL-60B, RL-HB, RL-HA and RL-HL lasers. One single-slopemodel is available, the RL-H1S. Topcon offers threedual-slope models, the RL-H2S, RT-5Sa and RT-5Sb.

TOPCON LASERS

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6TOPCON LASER CONTROL

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THE RECEIVERS

THE MAST

Topcon also manufactures two types of 360-degreelaser receivers for machine control use, the LS-B2and the model 9130 Laser Tracker. The LS-B2 wasdesigned to function as an all-in-one simple, manualindicate control system and for use by fully automaticsystems. The Laser Tracker is used almost exclusive-ly with automatic grade control systems like theTopcon motor grader system.

Just like the Sonic Tracker, the Laser Tracker must bepositioned on the equipment so it moves as theblade moves. Additionally, the Laser Tracker must bepositioned so it can receive the rotating laser beam.

To allow for maximum adjustment range in locatingthe laser beam, the Laser Tracker is almost alwaysmounted to a vertical pole called a mast. The mastitself is designed to mount to the same L-bar Bracketthat supported the Sonic Tracker. This also makeschanging between laser and sonic grade referencesvery easy to do right on the job.

Like lasers and receivers, Topcon offers the gradingcontractor a choice in types of mast.

The mast most often used for automatic grading iscalled the Trackerjack. It’s a very portable andrugged mast that allows the operator to raise andlower the Laser Tracker electronically from the cabusing the control box. This makes positioning theLaser Tracker very fast and allows for quick elevationchanges if terracing is being done.

A fixed mast called the Vibration Pole is also avail-able. It’s rugged like the Trackerjack, but requires theoperator to manually raise or lower the Laser Tracker.For contractors who use sonic control primarily, butoccasionally grade a pad, the Vibration Pole is aneconomical alternative.

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7 USING LASER CONTROL

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OBJECTIVE

SETTING UP THE SYSTEM

Using laser control is much like using sonic controlexcept a laser beam replaces the stringline or otherphysical grade reference. Since the rotating laserbeam can cover the entire job site, the control is veryconsistent and more than one piece of gradingequipment can be one controlled from the samebeam… talk about high production!

There are two main components to setting up thesystem for laser control. Positioning the laser andpositioning the receiver/blade. Depending on the jobrequirements—level, single or dual slope—position-ing the laser can be a snap or require just a littleplanning and skill.

There are three points to remember when positioningthe laser:

• beam elevation• laser location on the job site• orienting the laser to match the desired slope

or slopes

On most jobs you’ll want to position the laser at aheight that allows the beam an unobstructed path tothe laser receiver. If the receiver can’t “see” thebeam, the system can’t operate. This means gettingit high enough so it’s over the heads of people on thejob. Most medium sized tripods are capable of that,but it’s always a good idea to get a heavy tripod witha height adjustable head. This provides the laser withmore stability and allows you to fine adjust the heightof the beam when necessary.

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7USING LASER CONTROL

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SETTING UP THE SYSTEM continued

The physical location of the laser on the job siteshould be outside the actual grading area if possible.Topcon lasers feature a beam range from 500 to2,000 feet, so locating the laser outside of the grad-ing area shouldn’t be a problem.

When picking a location, also consider the distancethe laser beam will have to travel to reach the far-thest point on the site. Try to keep that distance assmall as possible to maintain the best possible grad-ing accuracy since any beam deviation from truegrade will increase with distance.

Lastly, if slope is being entered in the laser beam, thelaser must be oriented so its grade axis matches thedirection of slope on the slope (image 55). Grademisalignment is a major cause of grading inaccura-cies when using laser control.

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JOB EXAMPLES

Let’s look at the following grading jobs where lasercontrol will be used and determine where the lasershould be located.

Job 1: Level Building Pad

A level building pad 100 feet wide by 200 feetlong.

The laser should be placed outside the grading areaas close to center as possible of either of 200-footlong sides. The longest distance the beam will haveto travel would be less than 150 feet.

Job 2: Single Slope Loading Area

A warehouse loading area that is level parallel tothe building but is sloped at 2.00 percent gradeaway from the building.

This requires at least a single slope laser, the TopconRL-H1S, or a dual-slope laser setting one grade axisto zero and the other to 2.00 percent grade. Again,the laser should be positioned outside the gradingarea as near center the longest side as possible.Once the laser is located, it will need to be preciselyoriented so the axis of the laser being set to 2.00percent grade is perfectly parallel to the direction ofthe slope to be graded.

Job 3: An Airport Runway Extension

An airport runway extension that slopes 1.75 percent and has a 1.00 percent crown.

This job would require the most accurate dual slopelaser available, the RT-5Sa. Any dual slope lasercould be used, but the RT-5Sa is not only the world’smost accurate laser, it also features a very long-range beam—up to 2000 feet—and the ability to pre-cisely align the grade axis automatically.

To orient a dual-slope laser on this job, you’d have tofirst determine the location of the laser. It should beplaced no further away than 75 percent of the laser’sspecified beam range (image 59). This helps toinsure a strong laser signal even on a dusty site. Soif the specified beam range is 1000 feet, the lasershould be placed no more than 750 feet away fromthe start of the job, allowing the beam to cover 1,500linear feet of the runway. If the extension is less than1,500 feet long, just position the laser at the halfwaypoint.

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7USING LASER CONTROL

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JOB EXAMPLEScontinued

Since the runway is crowned, you could place thelaser directly over the crown (image 60), then simplychange the cross-slope entered from positive to neg-ative to grade the other side without having to moveand re-align the laser.

After the location is determined, the laser must beroughly positioned so the grade directions of lasermatch the grade directions of the job. As grade is entered in a laser, the beam plane is tiltedin a direction parallel to that grade axis. If positivegrade is entered, the beam plane rises in the positivedirection of that grade axis. Most lasers have mark-ings on the housing that indicates the positive direc-tion for each grade axis (image 61).

This runway extension requires a positive 1.75 per-cent grade away from the existing runway and a pos-itive 1.00 percent cross slope (image 62). The laserwould need to be oriented so the positive gradedirection of one axis points away from the existingrunway and the positive grade direction of the sec-ond axis points toward the crown.

The laser is now roughly aligned to the grade direc-tions, but accurate slopes require precise gradealignment.

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MANUAL GRADE ALIGNMENT

The most common method of grade alignment is tovisually sight down the grade axis of the laser androtate the instrument until it is aligned with a gradedirection marker down range, usually the gradechecker holding a grade rod or pole. The line createdby the laser and the marker must be perfectly parallelto the desired slope. So however far offset the laseris from the edge of the job, the marker must be offsetthe same distance. Also, the further down range themarker can be positioned, the more accurate thealignment should be.

Most single and dual slope lasers incorporate sometype of sighting mechanism on top of the laser that’scalibrated to the grade axis of the laser. On the RL-H1S peep sights are standard. The RL-H2S includesa magnifying spotting (image 64) that can be posi-tioned over either grade axis.

Once the primary grade axis is aligned the cross axisis automatically aligned, as it’s always 90 degrees tothe primary axis.

After the laser is properly set up, setting up the con-trol system is not much different than using a SonicTracker. The operator will mount the mast and LaserTracker to the L-bar bracket on the moldboard. Onthe mast side of the moldboard, lower the cuttingedge of the blade so it’s resting on a smooth area.

Position the Laser Tracker so an on-grade signal isobtained. If the Trackerjack mast is being used, thiscan be done from the control box in the cab. If afixed mast is used, the operator will need to manuallyposition the Laser Tracker, using the display lights onthe Laser Tracker to indicate when it’s on-grade.

Now grade a short pass with the system in automatic(image 65). Using the standard laser receiver, such asthe LS-70 that came with the laser, check the eleva-tion of the cut just made.

Calculate the needed cut or fill distance from thedesired finished grade and set that number in thedisplay per the procedure in the operating manual.The system is now set to grade.

By keeping the Laser Tracker in the beam plane, thecontrol box will visually guide the operator to grade,or in automatic operation it will control the hydraulicsystem to maintain finished grade.

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8SLOPE CONTROL

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OBJECTIVE

BLADE POSITION

Besides the grade reference sensors, the Topconsystem employs other more passive sensors thatmonitor and transmit critical information about themotor grader itself to the control box. These sensorsdo not require any external references like a stringlineor laser beam. That’s why they are referred to as pas-sive sensors. They use gravity and rotation to mea-sure angles and positions of the motor grader thataffects grade control.

This section will go into detail about how these pas-sive sensors help control grade.

The motor grader is a complex, fine gradingmachine. In the hands of an experienced operator,the blade of a motor grader can be oriented in analmost infinite number of positions to match thegrading application it’s being asked to perform.

The blade can be tilted forward and backward. Thisis known as blade roll. It can be rotated in a 90-degree arc perpendicular to its body. It can be side-shifted so it protrudes from either side of the body.

And in all the positions, it can be sloped side-to-side(image 68).

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8 SLOPE CONTROL

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BLADE POSITION continued

For accurate automatic grade control, the systemhas to know the orientation of the blade and machineat all times—what slope, what rotation, what tilt—anduse that data along with the information from thegrade reference sensor to accurately control theposition of the blade.

The Topcon motor grader control system uses threepassive sensors to accomplish this:

• slope sensor• rotation sensor• mainfall sensor located on top of the

hydraulic valve

Remote “Smart” Switch“High Flow” Hydraulics

Sonic Tracker IITM

Rotation Sensor

System FiveControl Box

Slope Sensor

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8SLOPE CONTROL

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THE SLOPE SENSOR

The slope sensor is usually mounted to the back ofthe circle. The moldboard is attached to the circleand as the blade is sloped or rotated so is the circle.The reason the slope sensor is mounted to the circlerather than the moldboard is the circle is more out ofharms way, lessening the chance of the slope sensorbeing damaged by grading spoil or being rakedagainst an object.

The slope sensor contains a level vial (image 71)similar to a standard vial in a carpenter’s level, butmuch more accurate. The exact position of the bub-ble is electronically determined by very accuratelymeasuring its position on a wire that runs through thevial. The slightest change in the slope of the bladecauses the bubble to move. The bubble position isconstantly monitored so the control box can calcu-late adjustments that must be made to maintain thedesired cross-slope of the blade.

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THE ROTATION SENSOR

The rotation sensor is mounted to the hydraulicswivel at the center of the circle. All blade rotationcenters on this point. As we mentioned before, themoldboard is mounted to the circle so its rotationcauses the blade to rotate exactly the same. Therotation sensor measures the amount of circle andblade rotation using a device called a potentiometer,and transmit that information to the control box soproper cross-slope can be maintained.

But why is it important to know blade rotation? Theslope sensor tracks the blade cross-slope, isn’t thatenough? No, it’s not.

If the blade was always parallel to the cross slope,the slope sensor would be all that’s needed. But theblade is often rotated to allow the spoil to be direct-ed away from the blade.

When the blade is rotated, it’s no longer aligned tothe cross-slope which means the cross-slope is nolonger accurate, exactly the same as a laser that hasbeen improperly aligned to grade. The greater therotation angle, the greater the cross-slope error. Bymeasuring the amount of rotation, a simple calcula-tion let’s the system adjust the cross-slope of theblade, eliminating any error.

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The mainfall sensor is mounted on the top of thehydraulic valve and measures the angle of travel ofthe equipment.

The mainfall sensor is much like the slope sensor,using an electronic level vial to measure the angle ofthe motor grader as it travels.

As the grader moves up a hill, the mainfall sensordetects and measures the upward angle and trans-mits the information to the control box so the leadingedge of the blade does not dig into the ground.

If the front tires of the grader traveled over a depres-sion, the mainfall sensor would detect the slightdownward direction and allow the system to auto-matically compensate, maintaining the smooth, pre-cise automatic grade control that has made Topconthe most widely used grade control system in theworld.

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THE MAINFALL SENSOR

NOTES

NOTES

This information has been gathered to provide data on the performance of KOMATSU and com-petitive machines under actual job conditions. Every effort was made to ensure reliable results.However, because of the many variables peculiar to each job (including material characteristics,operator efficiency, labor and other costs, haul road conditions, and altitude), neither KOMATSULTD., nor any of its subsidiaries or distributors can or does warrant expressly or implicitly thatKomatsu or competitive equipment referred to will achieve the performance or incur the costs indi-cated under other, though similar, circumstances.

The information contained herein is intended for circulation only to Komatsu employees and tothose distributor employees, whose duties require knowledge of such reports and intended solelyfor the information and training of these readers. UNAUTHORIZED USE OF THIS DOCUMENT ISHEREBY PROHIBITED AND THOSE RESPONSIBLE FOR SUCH USE SHALL BE SOLELYRESPONSIBLE FOR ANY DAMAGES WITH THIRD PARTIES THAT MAY INCUR AS A RESULT OFSUCH USE. Any reproduction of this release without the foregoing explanation is prohibited.

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