The more than 170 construction company executives, purchasing managers and machine operators invited to attend a John Deere product demonstration event in Sacaton, AZ in March 2009 are the driving forces behind some of the most successful organizations in the industry. One characteristic that this group shared is an aversion to resting on their laurels regardless of that past success. Always looking for any possible innovation that can increase operating profit margins, they came out to the Desert Southwest and witnessed something that everyone can appreciate: pure speed.
Among the machines that Deere introduced over two days was its new 764 High-Speed Dozer (HSD), which is designed to allow contractors to perform grading and moderate dozing at about double the speed of a similarly sized crawler dozer. Then the attendees saw the speed of a dozer double again when they saw the 3D-MC2 from Topcon Positioning Systems in operation on the 764 HSD.
Machine control automates grading
The 3D-MC2 system is an evolution of Global Navigation Satellite System (GNSS) machine-control technology, which is automating grading and excavation. Increasingly, GNSS machine-control systems are being installed on earthmoving, grading and paving equipment such as excavators, scrapers, dozers and motor graders, plus milling machines and asphalt and concrete pavers.
A GNSS machine-control system uses a rugged antenna mounted to a shock-absorbing, vibration-damping pole and a receiver box mounted in a secure location on the machine. Satellites send positioning data to another antenna/receiver combination at a stationary base station. Positioning data is also sent to the machine. The stationary base and machine work together to provide real-time kinetic (RTK) position information, revealing the machine's three-dimensional location on the site. Software compares the machine's position to the design grade at a given location. The design grade information was built from site plans.
The design grade data files are loaded into a machine-mounted control box via a USB flash drive. The control box updates positioning data and sends signals to the hydraulic valves. The blade is automatically positioned for elevation and slope. Other sensors inform the control box of certain machine conditions; for example, dozers are equipped with a slope (tilt) sensor on the blade to measure the cross-slope of the cutting edge. "Indicate systems" like Topcon's 3-D systems provide visual guidance for machine operators, who manually control the machine to cut or fill to the desired grade.
GNSS has become even more reliable and accurate in recent years by adding compatibility with the Russian GLONASS satellite constellation as well as the U.S. Global Positioning System constellation. This dual-constellation capability roughly doubles the number of signals available to the GNSS antenna/receivers and provides a high degree of positioning accuracy.
Testing indicates that the 3D-MC2 system can allow grading with twice the productivity and four times the productivity of grading without the use of machine control. Its components include a new MC-R3 GNSS controller unveiled at ConExpo 2008 that works in conjunction with an MC2 sensor that replaces a slope sensor; a four-color, touchscreen, Bluetooth-capable GX-60 control box; and a conventional GNSS antenna mounted on the dozer blade. The MC2 sensor combines a gyro, compass and inertial sensor to measure the X, Y and Z position as well as the roll, pitch, yaw and acceleration of the dozer. The technology gives the system the capability to provide blade position readings up to 100 times per second.