Construction equipment: digital digging

Komatsu developed the first machine control excavator, the PC210LCi-10

Building information modelling is rarely discussed in terms of earthworks, yet using 3D models with GNSS-enabled equipment – intelligent machine control – can generate 30% productivity improvements. Will Mann explains.

When weighing up ideas for improving productivity, construction professionals often overlook site equipment.

Indeed, in the CIOB productivity survey covered in pages 20-26, the industry ranked investment in areas such as plant and machinery last, when asked to assess the effectiveness of eight policies for raising construction productivity. 

That is surprising. For recent advances in digital technology used with construction machinery are resulting in massive productivity improvements. The companies leading the charge in machine control technology – where a combination of 3D terrain models and global navigation satellite system (GNSS) tracking is used to position and guide earthmoving equipment – agree that a 30% increase in productivity is possible, sometimes much more.

“The savings come mainly from the accuracy of the grading, which means there is no need to overlap the bucket, and elimination of rework,” explains Richard Clement, planning manager at Japanese construction equipment manufacturer Komatsu. “These savings result in lower machine hours, hence lower fuel usage and effectively an increase in tonnes per hour as an ultimate measure.”

“There are also reduced maintenance costs due to less wear and tear on the machine, and – although it is harder to quantify – less operator fatigue,” adds Neil Williams, engineering manager with positioning specialist Leica Geosystems, which pairs its technology with original equipment manufacturers (OEMs) for use on excavators and dozers.

Historically, cut-and-fill operations would be staked out by hand, and progress monitored by on-site engineers, using laser monitoring equipment. Machine control eliminates that.

“The stake-out is now done digitally,” says Peter Brooks, operations manager with Sitech, UK dealer for Trimble, another positioning technology firm which works with OEMs. “Surveyors create 3D models of the terrain, when they survey the site. This model is then transferred to the machine operator’s in-cab control unit, who uses it to plot the cut-and fill operation.”

Leica sensors mounted on the dozer use GNSS technology to display the machine’s position on the in-cab display (below)

The digital model makes it easier for engineers to tinker with the design, without having to leave their office, and plan the cut-and-fill so that no material needs to leave site. And from the operator’s perspective, machine control makes the digging execution far more efficient.

“The model is displayed to the operator in profile, plan and cross-section,” Brooks explains. “GNSS sensors on the arms and body of the machine show exactly where the machine is in relation to the design. The operator can track the movement
of the bucket and blade, and the display unit provides the cut and fill values down to within a centimetre.

“The cab display includes light bars which help the operator align the blade when digging out a particular section, for example a gully line. The bars are green as long as the operator follows the right alignment, but will turn amber if the machine strays off it.”

Brooks says the operator can use the technology in manual mode, where the light bars act as a guide, or automatic mode, where the blade is automatically moved to the correct position.

Surge in technology adoption

The last two years have seen a surge in adoption of machine control technology, according to Kevin Minton, director at the Construction Plant-hire Association (CPA). “Two years ago, the theory was known about but not widely used,” he says. “Now all the earthmoving contractors will have machine control-enabled kit in their fleet.”

Clement says use of the technology varies significantly by country, with the UK still some way behind northern Europe, and by business segment. “Here, we are seeing high use of machine control in road construction and housing developments, however there are still projects where, although the earthworks design exists as a 3D model, contractors are still not making use of the technology,” he explains.

One perceived barrier to its wider adoption is skills, though Williams says the technology is “not difficult” to grasp.

“Even someone with no prior knowledge of machine control can pick it up quite quickly,” he says. “You only need to learn its functionality once, which means less training, and increased motivation for the operator.”

Leica is currently building a training academy in Shropshire with plant hirer Hawk, and Williams says this will help grow the pool of operators who understand the technology. “The Construction Plant Competence Scheme (CPCS) needs a module on machine control, which it doesn’t at present, but we are working towards that,” he adds.

But perhaps a bigger obstacle to wider adoption is a lack of knowledge of the technology further up the supply chain.

“On the Aberdeen Western Peripheral Route, one of the UK’s biggest earthmoving jobs, there are 120 machines using our technology,” Williams says. “And that’s because an early decision was taken by the contractor team Connect Roads [a Balfour Beatty, Galliford Try and Carillion team] to use machine control. But that is rare.”

Clement says that, paradoxically, plant hirers may be reluctant to embrace machine control because the greater productivity will mean shorter hire periods. “The UK is quite unusual in how strong and influential the hire sector is, compared to in Europe,” he says. “We need main contractors and clients to become aware of the technology’s benefits, the time and money savings possible.”

In the meantime, machine control technology seems certain to advance further. So far, it has been chiefly used on excavators and dozers, though Komatsu and Trimble are investigating using the technology for compactors, where sensors automatically detect when the required compaction values have been reached.

Operational view of the monitor in a Komatsu excavator

Williams says: “If you consider that Formula One is the ‘playground’ for car innovation, mining is the equivalent for construction equipment. In that sector, there are driverless trucks which operate in mines. Obviously that is an enclosed, controlled environment where there are not as many safety risks. But I think that will eventually happen on construction sites too.”

Will the day come when robotic earthmoving equipment, controlled via 3D models and GNSS, is commonplace? Clement is cautious. “Current technology provides for semi-automatic operations, but operator input is still vital,” he says. “For example, encountering rocks in otherwise soft material will require the operator to devise a strategy to work around the obstacles.

“Komatsu is studying the possibility of surveying the working area for such hidden obstacles. But without an understanding of the surface and sub-surface conditions, full automatic operation is unlikely.”

But Clement believes there is “no doubt” that some level of robotic operation will emerge, given that “construction technology is just starting down the path of automation that manufacturing started many years ago”.

An indication of the wider potential for machine control can be found overseas. In Japan, where an ageing population has led to concerns about labour shortages, the government wants to boost construction productivity, and Komatsu has begun exploring the potential for using drones to guide automated machinery on some earthworks projects.

“The aim is to use technology to improve the construction progress, because they will have less worker hours,” says Clement.

Williams says that northern Europe is 10 years ahead of the UK. “In the Swedish market, their equivalent of Highways England has made machine control mandatory,” he says. “Leica alone does £1m of business a month in Sweden, whereas in the UK, the whole market for machine control technology is only £7m a year.

“So there is plenty of growth potential here – if we can get clients and main contractors to appreciate the technology.”

Case study: Collins Earthworks, Amazon distribution centre, Leicestershire

Collins Earthworks was appointed by main contractor Winvic Construction to deliver the cut-and-fill operation for retailer Amazon’s giant distribution hub in Ellistown, Leicestershire.

On the 370,000 sq m site, the earthworks contractor is using six dozers and three excavators, all of them working from 3D models loaded onto the in-cab control, and equipped with Trimble’s GNSS capability. The kit is supplied by Trimble’s dealer Sitech.

Collins director Patrick Gaffney says: “We are using the technology to control the layers of fill, delivering a maximum of 22 layers and an average of 14 across the site. We can cut to tolerances of within 10mm. It is a ‘balanced’ cut and fill, with no material going off site.”

Gaffney says the technology has made Collins’ operations far more efficient. “In the past, using a 2D approach, we have would had three or four people on a site of this size, setting up laser levelling equipment every morning, to measure progress of the earthworks and control all the plant we have here,” he explains.

“There is no need for that with the 3D system on the in-cab control, because the operators will now cut or trim to the correct level in the design, without the need for any checking.

“Without the technology, this job would have taken us 25 to 26 weeks. But we will finish in 22 weeks. The 3D model and GNSS technology gives us a real competitive edge.”

Intelligent machine control – key players

Komatsu – Japanese construction equipment manufacturer which developed the first machine control excavator, the PC210LCi-10. Komatsu uses GNSS technology from Topcon, combined with its own sensors and controllers, to create the machine control functionality.

Caterpillar AccuGrade – Cat’s machine control system comes pre-enabled on many of the manufacturer’s machines, along with GNSS-enabled technology. Cat has made AccuGrade open to third-party providers of positioning software, such as Leica and Trimble.

Leica Geosystems – Positioning technology specialist, providing a portfolio of products which link surveying software and equipment with machine control applications via GNSS. Leica sensors are mounted on to OEM (original equipment manufacturer) machines. 

Trimble – Another provider of positioning services and software, Trimble has agreed deals to integrate its GNSS-controlled machine control technology with OEMs such as Hyundai, Volvo and Doosan. Sitech is the UK and Ireland dealer for Trimble.

Topcon – Teams up its geospatial positioning software with OEMs such as Komatsu to provide machine control capability, plus tracking of other onsite activity such as haul truck movement. 

Prolec – Made its name providing sensor, hardware and software technologies for construction equipment to improve safety, though has now entered the machine control arena, also working with OEMs.

Moba – Known as a highways and waste management specialist, Moba provides measurement and control technology which integrates with earthmoving and road construction machinery.