For this project, Topcon NSW dealer Laserquip has set up Kelly & Shepherd's newest scraper, a 627G, for fully automated operation, rather than just as an indicate system (where the operator retains control of the machine, adjusting the scraper blade manually according to the screen reading). This is a world first.
Using a scraper with a GPS-based indicate system can be quite stressful on the operator once he is down to final trim level.
Indicate-only is fine for bulk cut and fill, because the operator just needs an occasional glance to ensure he is on grade. However, once he is down to the final 150 mm of cut or fill, the task is much more critical.
Not only does the operator have to steer the machine and watch the ground ahead, but he has to constantly watch the indicator bars on the screen, and adjust the blade up and down. At speeds of 8-12 km/h, he has to constantly think ahead, to adjust the blade correctly to ensure it lines up with the bars on the control screen.
And even the best operator's reaction times will lag behind the machine control system. All this is very stressful and mentally exhausting over an eight-hour shift.
Automated operation allows the cut and fill to be done in realtime, at the flick of a switch; the blade is constantly adjusted precisely according to the client's preset grade and level, freeing the operator up to concentrate on efficient steering and operation of the machine.
There is also less physical stress and strain, particularly in the dump operation. Typically, this requires the operator to glance back at the bowl every few seconds to ensure the load is being spread evenly.
With automated operation, the operator can concentrate on steering the correct path, with just the occasional glance at the screen and back at the bowl.
Switching of the system on and off is done through the joystick, and this also allows the operator to over-ride the system. For example, if there's a high spot, the operator can over-ride the automated system, cut off the high spot, then revert to automatic control.
Scrapers are an ideal way to cut, fill and level at the same time, due to their long wheelbase and speed over the ground. Kelly & Shepherd uses them for levelling for most of its bulk operations, and has been using them with lasers for this purpose for many years.
The company was a pioneer of GPS-based machine control earthmoving equipment, purchasing the first such system available in NSW.
Ever since automated GPS earthmoving equipment has been on the market, the company has considered trying to automate scraper operation - something that is difficult to do because of the nature of their hydraulic control systems.
This has only really been possible with the new generation of scrapers because their controls are electronic over hydraulic, making it much easier to achieve automated operation.
Garry Fleming and Jeff Bratton from NSW Topcon dealer Laserquip have done a lot of work, pulling apart the 627G's control and electronics system, looking at the specs, etc.
They designed a software program and circuit board to get the machine control and the scraper hydraulics to work together. According to Topcon in the USA, this has not been done anywhere else in the world before.
Being able to do this electronically has a number of advantages. It means not having to play around with the hydraulics, which is a very complex business.