Machine control has been quietly transforming the construction industry for a couple of decades, but 2D, 3D, and automatics for excavators have only achieved large-scale buy-in in recent years. At CONEXPO-CON/AGG 2026, every excavator OEM was discussing machine control, and the prevailing message was that contractors now expect technology solutions to be available and easy to integrate into their operations. This is a seismic transition for an industry that is slow to change. So how did we get here?
I explore that question with Volvo Construction Equipment’s Matthew McLean, a machine control specialist who has served as an educator both within Volvo and to operators. McLean has been a part of the construction industry’s technology transformation, both in his current role and as a motor grader specialist in the early 2000s. This breadth of experience, from early aftermarket indicate solutions to today’s advanced automatics, makes him the ideal candidate to help break down the evolution of machine control for excavators.
Let’s look at the technology’s development, how contractors came to trust it, and its impact on the construction industry.
The foundation of excavator machine control
While machine control for excavators has only become widely used over the past decade or so, the foundation of modern elevation control technology dates back over 60 years to the invention of the 360-degree rotating laser. Throughout the 1970s and 80s, these rotating lasers paired with sonic sensors could provide elevation control for motor graders and pavers. In the 1990s, advances in total stations and GNSS accelerated the development of 2D and 3D final pass precision grading solutions for dozers and motor graders, and today’s “big three,” Trimble, Topcon, and Leica, all offered aftermarket machine control solutions.
Precision grade technology is much harder to apply to an excavator, McLean explains. The complexity of joints involved in positioning the bucket, including movements of the boom joint, boom cylinder, arm joint, arm cylinder, and bucket cylinder, all have to be accounted for. This complexity limited machine control options for excavators until the 2010s.
Grade indicate solutions for excavators
There are two basic types of indicate solutions for excavators, and the first systems were all aftermarket add-ons, says McLean.
One method was to pair a laser sensor mounted on the arm of the excavator with a rotating laser and a grade stake. The excavator-mounted sensor would catch the laser as it rotated, then, depending on where the laser caught the joint, the system would indicate whether the operator was too high or low in relation to their programmed depth requirement.
“The nice thing about lasers,” says McLean, “is they had a very loud speaker on them. If you were high above grade, the laser would beep every couple of seconds. As you got closer, the beeping would speed up until it was a solid tone at grade. Some manufacturers did the opposite — a lot of tone when you’re far away and quieter when you get close.”
This method wasn’t the most efficient. After digging, the operator, or a labourer, would have to walk around the site with a laser sensor on a two-metre stick to check whether the excavation was on grade. Each area that wasn’t on grade had to be marked with spray paint: one mark for under-dug areas and another for over-dug areas. The operator would then get back to work, either backfilling or digging down as needed, until a consistent grade was achieved.
Rework is what machine control is designed to avoid, and contractors are only paid for digging, not for walking around with a grade stake or fixing work that isn’t on target, says McLean.
The second method, 2D visual guidance via tablet in the cab, is more efficient and the basis for today’s 2D systems. It tells the operator where to dig on a flat plane, relying on sensors that measure the angles of the boom, arm, and bucket to the edge of the tooth. Before digging, the operator sets the bucket down to create an elevation benchmark of zero and inputs the depth they want to dig. As they dig, the tablet displays the depth of the bucket relative to the benchmark.
This real-time visualization of the bucket depth includes both measurements and colour coding. As the operator progresses, the colour changes to indicate whether they need to dig deeper, are on grade, or have gone too far. The colour scale will vary, depending on the system provider, says McLean, but the principle is generally the same.
Initially, both of these guidance methods were only available as third-party additions, but by the mid 2010s, a few OEMs, including Volvo, were introducing proprietary machine control solutions.
Volvo introduced its 2D visual guidance system, Dig Assist, at CONEXPO-CON/AGG 2017 along with In-Field Design software and Co-Pilot, the Volvo-developed, Android-based tablet that serves as the in-cab command centre for software on Volvo machines. Dig Assist 2D relies on robust IMU (internal measurement unit) sensors on the boom and stick and GNSS antennas on the back of the excavator to detect machine rotation. It does not require a base station.
With Dig Assist, the operator can produce compound slopes. It also simplifies trenching, explains McLean. When the operator wants to dig a trench, they can touch two points with the bucket, and the system extrapolates a straight line on the Volvo Co-Pilot screen. The operator just needs to follow the line to dig their straight trench. The screen will let them know if they start digging to the left or right of that straight line.
Volvo later introduced a simpler version of Dig Assist without the GNSS antennas, Dig Assist Start, which comes standard on new Volvo excavators and can be used to produce simple flat surfaces or slopes.
Adding a base station or GNSS receiver allows the operator to use Volvo’s In-Field Design to draw complex shapes and slope profiles in the cab on the Volvo Co-Pilot tablet. With this set-up, the excavator can move around the job site, the system knows where the excavator is relative to the design, and the operator can dig to plan.
Select third-party 3D solutions for more complex profiles, such as roadwork that requires curbs, gutters, and utilities, were compatible with Volvo Co-Pilot by 2020, says McLean. With 3D, an engineer draws the plan in the office, producing a CAD file that can be loaded onto the tablet. Initially, USB sticks were used to load plans onto equipment. Today, plans can be transmitted via the cloud to connected machines.
By the mid-2010s, indicate systems for excavators were fairly established, says McLean, but while they can guide operators toward accuracy, indicate doesn’t stop them from making mistakes — that requires automatics.
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