February

February 2010

Excavator Machine Control Systems –1D, 2D and 3D simplified
For the newcomer machine control (this is also known as machine guidance) can be a tricky business to understand, and the number of solution providers and system types can cause much confusion. There are 3 common excavator machine control system types, known as 1D, 2D and 3D

What does 1D, 2D / 3D mean?
This refers to:

• 1 Dimensional (1D),
• 2 Dimensional (2D) or
• 3 Dimensional (3D).  

1D

1D gives the user a height reference only. This reference can be a numerical distance to target or by displaying a profile graphical model of the tool (or complete machine) and its proximity to the target line, with additional numerical information. This is the most basic of systems, yet is still a common type in use as it can assist a wide range of digging functions.

The 1D system has the minimum sensor requirement and only needs to monitor the moving articulation which for a monoboom machine are: Boom, Dipper, and Bucket

2D

2D refers to a system that will provide the operator with the 1D indication of the location of the tool point e.g. bucket – relative to a predetermined target reference, this is also known as the elevation reference (Z) as well as the tool point position in relation to a reference point (X,Y). This can be best understood by the screen graphic below:

This shows the distance to target (Z value) in both numerical and graphical terms and the X,Y position in the plan view relative to the desired trench design.

A 2D system provides more information and makes tasks such as grading slopes, trenching , complex profiles etc. easier as the slew rotation of the machine is taken into account in the measurement calculations and the subsequent displayed information. A 1D system does not do this and means you have to always operate with the machine perpendicular to the design – which is how some prefer to operate.

3D

A 3D system provides the same essential data as the 2D – location of tool point to a predetermined target – but – and this is the important bit – has the benefit of knowing where it is on the jobsite. This positional data is usually provided by GPS, but can also be obtained from other positional data interfaces such as a Total Station. This additional information allows the excavator to be placed on to the jobsite in a format showing the excavator relative to the complete design

Functionality and Capabilities

Whilst this will not hold true for all types of 1D, 2D and 3D systems what follows is a list and description of the expected operational capabilities of these systems:

1D and 2D System

• Use the system to excavate a range of profiles including level, gradients, dual slopes, trenches, complex (user defined) profiles.
• The system can be referenced to the dig or site bench marks.
• Excavator can be referenced to a site laser, this allows the excavator to be moved on site without the need for re-referencing to a ground based reference – removes the need for additional staking, ideal for large sites that need to graded with the excavator. With DigPilot this method of referencing is accomplished by using an arm mounted reference sensor that “catches” the laser signal and references the excavator.
• Tilting bucket options – if the excavator has a tilting bucket option this allows it to grade slopes from a single position whilst slewing the machine. If this is required the 2D system needs to be used to allow the capability of sensing the tilting bucket and the machine slew.
• System display shows both graphic and numerical data to assist on excavating to target. Graphics can be panned / zoomed.
• Multiple bucket options to give the operator the option of selecting / creating a wide range of buckets.
• Multiple machine storage – This requires the capability of storing additional machine calibration information for a quick and easy operation a useful option for someone with a smaller hire fleet that does not require machine guidance for all work.

3D System

A quality 3D system will have the options of the 2D system defined above with the additional benefits of:

• Place the machine within a 3D design model giving clear indication of location and depth to target.
• The system should be able to cope with 3D design files from a wide range of design packages.
• Option to select different job design layers (a design may contain many different design target layers) as well as the option to select overlays to indicate points of interest / avoidance zones and mark site points if required.
• Progress and quality of the grade / excavation should be recorded. This data can be exported to be used as evidence of work done.
• A simple switch between 2D and 3D operating modes. If the GPS goes down it may still be possible to continue the job using the 2D mode.
• Can provide the ability to integrate data within a site management software suite.

Summary

• 2D is useful within smaller projects having design areas that are of a simple nature e.g. slopes, trenches. Also a good back up option should GPS availability be limited / unreliable.
• 3D comes into its own on large jobsites due to the removal of site preparation needs and can provide necessary documented evidence of work done / to do. Allows an operator to work without supervision and the need for site design knowledge.
• 2D / 3D Machine Guidance will improve efficiency, productivity and accuracy. Some manufacturers offer an easy upgrade route from 2D to 3D enabling the user to learn the basics of work with the 2D option and be prepared for 3D as and when its use is required. The upgrade route certainly offers economic benefits.
• An often overlooked additional benefit both systems offer is reducing the number of people on the ground, especially the need for personnel near the machine whilst it is operating (e.g. banksman). Apart from the obvious labour saving issues, there is a simple equation: fewer people on the ground = safer site.
• No machine guidance application is too difficult.

January 2010

Machine control has the potential to become one of the most significant milestones to happen to our industry since the excavator replaced the shovel. It has the potential to increase the profitability and efficiency of every jobsite on which it is used, any contractor who chooses to buy machine control will have a clear competitive advantage over his competitors when bidding for jobs. These may be bold statements for a technology that still has overall market penetration of less than 10%, but the evidence is becoming overwhelming that machine control is a significant part of the makeup of the future of the construction industry.

But what actually is it?

Machine Control, Machine Guidance or in the case of exacavators dig depth monitoringis the application of technology such that it improves the operating accuracy and efficiency of construction equipment in highly measurable ways. It can be applied to a wide range of machines including excavators, dozer, graders, pavers etc. the list goes on.

Machine control gives precise guidance to the operator and in some cases has the additional functionality of actual hydraulic control of the machine. This hydraulic control functionality particularly applies to those machines with less complex tool movements such as dozers, graders and pavers where the machine control system ensures that the tool (blade) follows the desired level allowing the operator to focus on driving the machine and not having to control the blade equipment. Excavators have a more complexhydraulic control system and as such the machine control system does not have a hydraulic control function but instead the operation is concentrated on providing the operator with accurate guidance information.

Machine Control sounds great on paper (like many things in life aimed at making us work smarter), but where can it be applied and how effective is it.

The answer is not quick, any of the items in the following list is a justification for using machine control, and in most applications this will include multiple items:

Our many years within this industry have seen systems installed on all of the above applications and each has the benefit of saving costs, and these are seen in the following areas:

However, it’s not just about the money, there is the benefit of improved site safety :

These are very beneficial to those working towards a zero harm policy.