For the past few months I have spent considerable time “at the coalface”, meeting customers, demonstrating product, listening to their needs and trying to offer a suitable excavator machine control solution. It is a most refreshing experience and one I would recommend to anyone who wants to see how the real world works as it is a million miles away from the comfort zone of the office where you spend time designing and creating what you think the customer wants when in reality his actual requirements are far more practical and pragmatic than you realise. It’s surprising just how far off the mark we (machine control manufacturers) can be in some cases.

An issue of particular concern has come to light and that is the misrepresentation of machine control by individuals more concerned with increasing unit sales than helping the customer (and hence the ultimate cause of machine control acceptance by the majority). There are some truly shocking examples that I would love to be able to divest, but litigation laws won’t allow ! This practice is only made worse when product is being sold by agents who have no knowledge or experience of machine control, no knowledge of installation / calibration practices and just see machine control as another brown box product. Obviously this applies to a very small minority and I would like to make it clear that there are some exceptional people out there who truly understand and believe in their product, but as with all things it is the minority who grab the headlines and do, as I have found out, give a very bad name to machine control.

What this all means is that people who would love to enter the world of machine control are being sold short, they know it and are completely disillusioned and angered by the whole experience and want nothing to do with it again  – believe me it is happening.

So what can be done about it ??

A self policing industry – however, the industry is still too fragmented and driven by its own (understandable) commercial interests to have some sort of self appointed governing body to employ some form of policing – the start of trade discussions is happening, and there is a lot of co-operation between some manufacturers and distributors, but this is a long way off from signing up to any form of code of practice.

Education – try to increase the  quantity of useful understandable data that can be used to enable anyone to evaluate their needs against available product. This will also require making this information more readily available, there is plenty of useful data out there and some distributors are extremely informative and helpful, but they, unfortunately, are in the minority.  A lot of useful manufacturer specific data requires some real detective work.  This is why Machine Control Online was created – to give an impartial, honest view of the machine control market and help everyone to increase their knowledge and understanding.

So as a start towards this, let’s review basics from the point of view of you - the potential owner / user :

Question: I have an excavator and want to dig more accurately and efficiently, how can this be done ??

Not an unreasonable question, but needs more detailed evaluation first before offering solutions.

What excavator are you using ?

What are you trying to dig ?

What current working practices / methods do you employ?

Is it a simple level grade, a slope (single or dual?),  a profile,  a trench ? does the trench have a grade, if so how precise ? is it all of these applications ?

Are you working from a 3D plan ?

There are many more that can be asked, but you get the idea. If you are not being asked these questions then beware, this is fundamental stuff and needs to be known before any form of opinion of your needs can be reached.

Ultimately what we as distributors and manufacturers are trying to determine is the level of system complexity that the customer needs, is it going to be 1D, 2D or 3D and what he can expect in terms of an increase in productivity and efficiency? Trying the hard sell on 2D and 3D when all that is required is a 1D system is not good, and vice versa.

A quick summary of the difference between these system types :

What does 1D, 2D / 3D mean  ? - This refers to 1 Dimensional (1D), 2 Dimensional (2D) or 3 Dimensional (3D). 

1D – 1D gives the user a height reference only . This reference can be a numerical distance to target or by displaying a profile graphical model of the tool (or complete machine) and its proximity to the target line, with additional numerical information.  This is the most basic of systems, yet is still a common type in use as it can assist a wide range of digging functions.

The 1D system has the minimum sensor requirement and only needs to monitor the moving articulation which for a monoboom machine are : Boom, Dipper, and Bucket, an ideal application would be on backhoe type machines.

2D - 2D refers to a system that will provide the operator with the 1D indication of the location of the tool point e.g. bucket – relative to a predetermined target reference, this is also known as the elevation reference (Z) as well as the tool point position in relation to a reference point (X,Y). This can be best understood by the screen graphic below :

This shows the distance to target (Z value) in both numerical and graphical terms and the X,Y position in the plan view relative to the desired trench design. 

A 2D system provides more information and makes tasks such as grading slopes, trenching, complex profiles etc. easier as the slew rotation of the machine is taken into account in the measurement calculations and the subsequent displayed information.  A 1D system does not do this and means you have to always operate with the machine perpendicular to the design – which is how some prefer to operate.

The 2D system has the same sensor requirement of the 1D with the addition of a pitch and roll sensor and slew rotation sensor.

 3D – A 3D system provides the same essential data as the 2D – location of tool point to a predetermined target – but - and this is the important bit - has the benefit of knowing where it is on the jobsite. This positional data is usually provided by GPS, but can also be obtained from other positional data interfaces such as a Total Station. This additional information allows the excavator to be placed on to the jobsite in a format showing the excavator relative to the complete design

Understand the advantages that machine control will give you, for example :

Less men on site (machine control can remove the need for grade checkers and banksmen)

Right first time excavation

Easy and quick method of checking work done

Removes the need for setting the site out (batter rails etc).

Allows operators to work autonomously

Another very misunderstood area is that of accuracy. I am tired of manufacturers trying to outdo each other on spec., sometime quoting unachievable or pointless performance characteristics. It’s like when you purchase the latest state of the art sound system and it offers 0.00001% less THD (Total Harmonic Distortion) than the competition – only a bat with perfect hearing could tell the difference but customers will still be swayed because of the stats !!

It’s as simple as this – most sensors are using very similar technology and have pretty much the same accuracy. The best accuracy of any angle sensor currently available is little better than 0.1⁰ that means that on an excavator with 10m reach will have a worst case elevation and reach accuracy of +/- 17mm.

It is possible with a 1D or 2D system to mask some of this error as using these systems require local referencing (to a bench or laser level) and this trims out the error of small movements of the excavator, however do not be surprised if the system shows a worst case of +/- 17mm under test conditions.

A 3D system does not have the luxury of local referencing and relies upon the 3D terrain data and the accuracy of the RTK GPS. The errors in 3D will accumulate, therefore if you have 20mm GPS height  error, 17mm sensor error then it is possible to have at best 37mm accuracy and this is assuming that the excavator is in ideal condition, has been perfectly measured and calibrated and that the 3D terrain data and GPS localisation is correct. Trimming of these errors can be done on site, but whenever the machine is moved to a different localised area then the trim data would need to be readjusted.

But the sensor accuracy is only part of the story, the overall system will only be as good as the calibration. Another important, often overlooked area (until it’s too late) is that of actual performance. How does the sensor respond in real time ?? You don’t want to have a system that is so sensitive that it is impossible to operate at anything other than a dead slow speed and likewise you don’t want the system response so deadened that the displayed data is constantly playing catch up with the real time movement of the machine (for more useful detailed information about sensors and generic system types please refer to my previous articles).

So what do you do to fairly assess a machine control system ?  Simple - ask for a live demo.

Live demonstration

If possible ask to see the system demonstrated on an excavator - preferably one that you own, under your test conditions, this is after all how you will be using it and only by seeing the system in action can you truly evaluate it. See how complex the install is and how complex the calibration process is – bear in mind that you may have to do some of your own support if problems occur and a service engineer is not available for a period of time, does the demonstrator understand his subject and is he capable of providing satisfactory answers to any questions.

During demonstration take measurements and satisfy yourself that the accuracy is correct for your requirement, take a number of readings at different heights and radii with the bucket in different positions, don’t just settle for one test measurement.

Attempt to set the system to different functions and see how easy it is to set a grade, level dig, referencing etc.

Doing this will not only help you in your decision making process, but it is a great way of being able to instantly realise the benefits of machine control.

So, please, don’t be put off by any horror stories that you might have heard, if you do your homework, prepare properly, make the sales demonstrator sweat a bit and follow your own common sense then you should be able to make your own objective judgement and hopefully enter the world of machine control unscathed.