With its new mastless graders and capability to create 3D designs, Cat® has unleashed the full potential of the blade.
The Global Navigation Satellite System, or GNSS, technology was officially introduced as a guidance system for earthmoving machines in the late 1990s.
When the GNSS made its debut in the construction sector, dozers and motor graders were the machines of choice to use this literally groundbreaking technology.
At this time, the technology was often only used on large scale projects with complex office-based designs created in expensive CAD software packages.
On the machines like motor graders, receiver masts — antenna-like sensors — had to be mounted to blade to provide accurate guidance.
But the physical nature of the masts came with problems, notably exposing components to potential damage from the environment and theft and limiting the movement of the blade and productivity potential of the grader.
It has therefore been no surprise that over the past few years, the development of Caterpillars mastless graders has been part of the next wave of innovation in GNSS technology.
The first Cat graders equipped with the new integrated system – officially tagged Mastless GRADE with 3D – were the Cat 140, 150 and 160 which are now available in both T3 and T4 emission packages.
The system integrates the GNSS receivers and IMU (Inertial Measurement Unit) grade sensors right into the grader, without restrictions from the masts sticking out, visibility being interfered with, or cables getting in the way.
Wheel lean, drawbar offsets and frame articulation can be positioned without restriction from masts or cables, expanding the use of the grader in finishing applications such as side slopes and drains where guidance was not previously possible due to the mast positions.
Another key enhancement of GNSS technology has been “ease of use” and ability for operators to easily build their own “3D Infield designs” in the cab of the machine as they work.
This has been made much easier with state- of-the-art Cat GRADE display which features a high-resolution colour 10-inch (25cm) touchscreen monitor with excellent daylight readability.
To put the “ease of use” of the Cat GRADE 3D system to test, a recent demonstration using a Cat 140 3D Mastless grader was held at Maryborough, Victoria.
The event was hosted by Cat Technology Application Specialist Chris Barrett and demonstrator John Merlo, from Cat dealer William Adams.
The objective was to demonstrate how to use the Cat 3D Mastless grader to build an “Infield 3D design” to aid road maintenance on unsealed roads grading in regional areas.
Traditionally in road maintenance application, Cat GRADE Cross Slope been used as a base technology.
Cat GRADE Cross Slope automatically controls one side of the blade to maintain a consistent surface while the operator manually controls the elevation.
Using Cat GRADE and 3D with design, full blade automatics can be used.
This enables the same road design to be used year after year, providing an accurate, consistent smooth road, and greatly speeds up maintenance and reduces the material required when re-sheeting. Automatic side shift can be used to perfectly shape the crown and road edges.
To build a design for the road from scratch, John simple drove the grader down the center of the road, recording “3D points” from the cutting edge.
These points automatically created a horizontal and vertical alignment forming a 3D center line.
Then using the touch screen, John drew in a cross section of the road with three per cent crown either side of the centre line.
These two simple steps created a 3D design for the length of the road.
The design then was then used to shape up the unsealed road using the Cat 140 3D Mastless grader.
“Building the design, you can start off simple or you can put the full profile of the road including ditches and shoulders,” John said.
“You can make it as simple as complex as you want. And you can position the blade any which way you want it to get the most productive outcome.”
John found it particularly useful that infield designs could be applied to the machine while working on a country road, without the need for surveyors coming out or having to own office CAD software.
Connectivity
To use Cat GRADE 3D, the machine needs to be connected to a base station broadcasting Real-time Kinematic messages (RTK).
In this demonstration, the Virtual Reference Stations (VRS) network was used, and the grader was approximately 5kms from the nearest station.
The VRS network has base stations throughout Australia. The RTK messages are available from the Reference Stations via 3G/4G cellular networks.
“When using VRS network, you want to make sure you’re not too far away from nearest reference station and that you have got good mobile phone coverage; both can be checked easily on coverage maps,” Chris said.
“When cellular coverage is not available, or the machine is working in areas where the VRS network is not available, then connecting to a local base station on the jobsite using UHF radios is the recommend and most reliable method.
“Using UHF radio eliminates the reliance on the phone network and can keep you using the system.”
Caterpillar machines equipped with Cat GRADE 3D use the cellular Product Link radios and Cat UHF Site Networks radios.
In addition, the VisionLink Productivity application can be used to send design files over the air from the office as well as enable remote support of the GRADE display.
The remote support feature via VisionLink Productivity is handy for assisting operators remotely and reviewing completed work.
adjust blades accordingly.
Tree coverage
The latest GNSS receivers used in Cat GRADE 3D have increased accuracy in challenging environments due to improvements in satellite signal processing.
“It was impressive of how well the receivers performed today when much of the road has heavy tree coverage,” John said.
Operator feedback
Ultimately, the system takes the guesswork out of grading.
“Once you put the alignment in there and you’re working to a design, that takes a lot of the guesswork and estimations out of it for the operator,” Chris said.
John said use of the automatics made him realise just how imperfect many existing roads are.
“With the system, it’s so much better and you have the design locked in,” he said.
“There’s no more freehand work or just cross slope blending it in … now that we have a fixed alignment and cross section, you can come back to when needed to maintain, reshape, on the existing design,” he said.
“As someone who has been maintaining gravel roads in the local government environment, and now jumping into the 3D system and building a model to shape up a road, I think the Cat GRADE Mastless graders will go down a treat and will be accepted by road operators.
“Once you get your head around it and understand how it works, it’s very, very easy and you get consistency in all your roads, drains, formations.
“I think it would make life a little bit easier for operators using the system.”
Chris said anyone who wanted to give the Mastless Cat graders a run can contact their local Cat dealer or visit operatortraining.cat.com.
