The Trimble PCS900 is a 3D machine control solution designed to allow contractors to mill out longitudinal waves and ensure the smoothest possible surface for paving. In addition to providing a smoother surface, using 3D machine control on a milling machine also means shorter lane shutdowns, reduced machine wear, less material to remove and less asphalt usage.
Here’s how it works:
The 3D surface model created in Trimble’s Business Center—HCE software is loaded into the control box. The 3D design is displayed to the machine operator on the control box, showing areas that are on, above or below design grade.
Next, the machine is placed at the start of the milling project with the mill head lowered to the existing surface. Initial cuts are made to get as close to desired grade as possible.
From there, the operator puts the system into “automatic” mode. As the mill travels forward, the system compares the actual drum position and slope with the digital design. A Trimble SPS930 universal total station sends corrections via radio to the machine control system, and the mill head is adjusted accordingly to keep the mill on design.
The Trimble PCS900 automatically guides the milling drum to cut the ideal depth and slope without string lines or manual adjustments. The total station locks on to the machine target, ensuring millimeter control of the milling machine drum. Universal total stations are designed to be more accurate than GNSS guided systems, and are not affected by interference from trees, buildings, bridges and other structures the way GNSS is, according to the manufacturer.
The automated, 3D system ensures the smoothest possible surface is left behind while also removing only what needs to be removed, which also minimizes the amount material that is hauled away.
As a final step, a grade checker uses a total station rover to verify elevations. This is to ensure that the design surface was met and that no offsets or adjustments are needed for the machine control system.
For more information, contact Kevin Garcia, business area manager for paving and specialty construction in Trimble’s Heavy Civil Construction Division, at Kevin_Garcia@Trimble.com.