Remote control and automation were once the preserve of the boffins but are now becoming commonplace on construction sites, reports Phil Bishop
THE USE of wireless remote control for construction machinery has generally been limited to two types of equipment: lorry loader cranes and small tower cranes, particularly the self-erecting type.
In both cases, UK construction has come late to their use. Lorry loaders in mainland Europe are much more likely to have remote controls than in the UK, says Alan Johnson, chairman of the Association of Lorry Loader Manufacturers and Importers.
According to industry estimates, only about a third of new lorry loaders are specified with remote controls, although the proportion is rising every year. Remote controls are standard with self-erecting tower cranes but compared with mainland Europe, the use of self-erectors is limited in the UK. But, here again, the numbers are rising.
What all this means is that each year, with the increasing use of remotecontrolled lorry loaders and self-erecting tower crane, the use of remote controls is rising.The benefits of remote control are also beginning to be recognised by users of other kinds of equipment.
Gerry Barker, managing director of Koppen & Lethem, distributor for the Swedish-made Scanreco remote-control systems, reckons there are three main benefits of remote controls, each interrelated.
The first is that the operator can position himself in the position of best visibility.With a lorry loader, for example, the operator can walk around and follow the load or, if he is delivering a pallet of roof tiles, he can position himself on the roof of a building and deliver directly to where they are needed.
The second big benefit, Mr Barker says, is safety.The operator can stand clear of both the machine and the load, either of which can sometimes represent a hazard.He adds that the operator can also get distance from the hazard of a particularly noisy piece of machinery.
The third benefit is that remote controls can reduce manning, since they enable one-man operations.
The operator can sling the load himself and act as his own banksman.Given that banksmen are often less experienced or less well trained than operators, this can also improve safety, as well as reduce costs.
Technically, it is straightforward to add remote controls to hydraulic machinery and remote control systems manufacturers are always looking for new applications to which it can sell the benefits.
Other applications that use remote controls include load haul dump systems and rock breakers in mining, tunnel boring machines (on the Jubilee Line Extension, for example), trench compactors (to avoid the risk of vibration white finger), concrete pumps and demolition. In demolition, an operator sitting in a machine may be exposed to the risk of a structure falling on top of him, or collapsing underneath.
In November, Midlands-based demolition contractor Coleman & Company added remote controls to a Komatsu PC45R-8 mini-excavator to work to demolish part of the Fort Dunlop building in Birmingham, which is being refurbished.Working with its supplier, Marubeni-Komatsu and Koppen & Lethem, Coleman also adapted the machine so that the cab could be removed in order to reach confined areas.
When the cab is removed, a protective housing is inserted to protect the electronics from falling debris.Other built-in safety features include automatic shutdown and twoway information transfer to provide continuous communication between the machine and the remote unit.
Contracts director Mark Coleman said at the time: 'The Fort Dunlop site requires our operatives to work at heights, creating voids from a concrete base with drops of up to 40 m below them.The job also involves working at exposed edges and we were uncomfortable with the idea of a manned vehicle in such situations.There are plenty of machines around that can do the demolition work but not with remote operation.'
A remote-controlled excavator proved the ideal solution, he said.The machine was subsequently used for making major structural alterations at Birmingham Town Hall, working from a temporary structural steel deck to remove the upper and lower gallery.
Another company embracing remote controls, in a different application, is piling contractor Roger Bullivant.The majority of Bullivant's fleet of rigs have been converted to radio remote-control.
'The initial idea was to make it simpler for the operative to run the machines, ' says plant design manager David Spriggs.'The remote operation takes the operative away from the levers on the side of the machine and allows him to operate from the front end.There is a safety issue as well. Instead of the operator being so close to the machine, he can not only oversee the piles being delivered into the ground, but he can also work at a safe operating distance.'
The first remotes used by Bullivant were tested on the smaller rigs without cabs and were still connected to the main machine by a cable. But by 1997 the company had developed a fully radio remote system and today has more than 30 rigs operated by radio remote working.
WHILE remote control allows the operator of a machine to stand some distance away, remote diagnostics enable a machine to be repaired from the other side of the world.
Modern plant is controlled by on-board computers, which the manufacturers can access via a modem. If the machine malfunctions, the manufacturer may not have to send a repair man to site. In many cases a technician can assess the problem just by looking at a computer screen and fix it from his desk.
While customers in construction have not taken great advantage of this service, on applications where continuous operation is absolutely critical, such as ship-to-shore container cranes, remote diagnostics have proved their worth.
As well as fixing problems, remote diagnostics also helps with preventative maintenance.Data loggers record what work has been done and replacement parts, such as filters, can be dispatched to site automatically just as it is time to fit them.
THE GOOD news for plant operators is that remote controls can make their job easier and safer, yet the operator is still very much required.
The bad news is that the next step is automation, with no operator required.Automation and robotics is some distance in the future for construction, but this is not science fiction. In Germany, the university of Stuttgart is developing a bricklaying robot and in The Netherlands the university of Eindhoven is developing a floor-tiling robot.To date, the robots are more expensive than people but that could change.
In industrial environments, overhead cranes and warehouse stacking systems are quite commonly automated.The issue for construction is to develop standardised procedures that eliminate the need for personnel. Japanese contractors have taken the lead here.
They have run pilot projects that involve using bar codes or radio frequency identification systems. Components of a building, such as cladding sections or steelwork, are tagged at source with information that dictates precisely where in the building they are to be placed.When they arrive at site, they are unloaded automatically by a crane that has been programmed to recognise them and know where to put them.
Shimizu's SMART system automates construction of high-rise steel-frame buildings, allowing work to take place safely in any weather and it is now applying its technology to reinforced concrete structures.High-grade prefabricated elements produced at an on-site plant are transported using separate systems for vertical and horizontal movement to ensure maximum transport and assembly efficiency.
The building's top floor and roof are erected on top of four jacking towers.The top floor assembly then acts as the main work platform, on which sits lifting machinery and automatic conveying equipment, making the shell look like a factory with automated gantry cranes.
Components introduced at ground level are placed automatically. Shimizu has used this in Singapore as well as Japan and claims that it speeds construction by 30 per cent.