Getting the good oil on machine control

The civil and mining industries are embracing machine control as the norm, says GPS systems authority David Klease. The national machine control manager for CR Kennedy & Co. presented a seminar on the topic to the CCF SA branch AGM in September.

He advises that the trend today for many principal contractors is to seek out and hire subcontractors who have 2D system functionality on their machines in the minimum, and often the requirement is no less than 3D functionality.

The systems, he says, save time due to the high accuracy they produce. Less passes are necessary and this saves on machine wear and tear and frees the machine up to move onto the next part of the job. The initial investment is quickly paid off.

Klease says the operator of a machine fitted with a guidance system still commands the machine and is in full control the system will not override the operator.

The 2D system is programmed with the machine dimensions and angles (boom length, stick, bucket width etc) and can reference off the ground or a peg. Changes to cut, fill and depth can be made.

The system understands how to measure a depth from the reference point and gives this information to the operator on the screen in the cabin.

When using the Leica Power Digger 2D system, for example, both the operator and the system know exactly where the machine bucket is at all times. Three sensors on different parts of the digger (Fig. 1) connect to a screen in the cabin.

Whenever rhe machine moves, a graphic of the bucket moves with it in real time, on the screen. That shows the operator what is happening even in blind cuts or under water. The system will display how far to dig and the grade of the job with up to 10mm accuracy.

As to the term 3D GPS, Klease says GPS stands for global positioning system; 3D refers to the machine control running in three-dimensional mode. The Leica Power Digger 2D is upgraded to 3D by adding the necessary components antennas to pick up the satellite signal, the 3D screen (a small computer), GNSS power box and radio (Fig. 2).

Before starting a job, the site project manger provides the operator with the site plans that are loaded into the 3D screen via a USB. As the machine moves, not only are the movements shown via the sensors like in 2D but also where the machine is according to the site plan via satellite signal.

A reference station is erected on the site and communicates via a radio with the machine. Project data is compared to the machine position. The difference, being cut and fill values, is displayed.

Klease says machine control is available for dozers, diggers, graders, barges, pavers, piling rigs and drill rigs.

More information: Stefana Vella, svella@crkennedy.com.au