Gundersen & Løken: Tracking the tip of the bucket

Image: Septentrio

Gundersen & Løken AS, in Oslo, Norway, founded in 1899, develops equipment for the construction industry. It uses Septentrio’s AntaRx in its Dig Pilot 3D machine guidance system, which it began to develop in 2007. The company is now launching the next-generation DigPilot to assist excavator drivers. Its DigPilot Terra user interface and graphics offer a wide range of functionalities for efficient earthwork. The development of DigPilot Terra is funded partly by Innovation Norway.

DigPilot uses multi-axial CAN bus angle sensors on all moving parts — chassis, boom, arm and bucket — to calculate the position of the bucket tip with centimeter precision. The sensors are gyro-stabilized and hold firmware that predicts angles in the coming milliseconds based on angles from the previous milliseconds. These calculated angles are pushed to the computer in the cabin, which can visualize the bucket position in real-time.

DigPilot is a two-antenna system. Until now, it relied on two Septentrio GNSS antennas installed on the rear of the excavator — one to determine the machine’s position and one to determine its heading. These data are fed to the Septentrio GNSS receiver (rover) inside the machine, which also receives correction data via internet or radio. The data from the GNSS rover is pushed to the computer in the cabin and, when combined with the angular sensor data, provides the exact coordinates of the bucket tip and the delta value of the finished project.

Now, Septentrio’s AntaRx technology makes DigPilot’s installation simpler and more robust because the built-in GNSS rover in one of the rear antennas greatly reduces the amount of cabling and the number of connectors.

I discussed DigPilot with Eric Floberg, the company’s managing director since 2019 when he took over from his father, and Erik Sørngård, the company’s R&D manager, who has been working with Septentrio products for 12 years.

When did you start working with Septentrio on AntaRx for DigPilot? At what stage of deployment is it?

Sørngård: We began to discuss features about four years ago. At that time, we had worked with other Septentrio products for eight years. So, they appreciated our cooperation and wanted to show us where their next stage in development was heading. Last year, they approached us again, to see whether we could start looking further into it.

Floberg: We now have one system here for testing and we have experience from the previous Septentrio products, such as the rover GNSS receivers, which have always given us the best of accuracy. Of course, now, we see the potential to make our system more robust and simpler. As soon as we have sold out the existing Septentrio products, we will incorporate the AntaRx into our next-generation machine control system.

Is DigPilot receiver-agnostic, even though you have a preference for the AntaRx?

Floberg: All the connections, the cabling and the components themselves are exposed to very tough environments and stresses of different kinds, such as extreme temperatures and vibrations. So, reducing the number of components and connections and cabling would definitely give us a higher uptime, which is the most important thing for our end users.

Having the antenna and the receiver in the same box means less cabling and easier installation, correct?

Floberg: Definitely. The anti-theft aspect here is also very important. In certain parts of the world, you will appreciate the opportunity to easily remove it from your excavator or bulldozer when you leave at night.

What are the key challenges?

Floberg: This winter has been the toughest one in Norway in 30 years. We have also had the chance to do some testing in very low temperatures and harsh environments. When we see it work as well as it does, we feel very confident about it.

What accuracy have you been getting?

Sørngård: When it comes to machine control, we look at the end result on the tip of the bucket. We have several sensors, and we have to calibrate the machine accurately. The receiver is not the biggest contribution to the noise in the algorithms. We trust that the Septentrio receiver delivers accurate numbers, and we must push ourselves to make the rest of the system meet the same standards.

Floberg: On 30-ton or 40-ton excavators with booms up to 10 meters long we are able to get sub-centimeter accuracy, but the tip of the bucket in such a machine is 1 in thick. Of course, there are many other factors, such as the wear and tear of the machine.

Is DigPilot typically factory-installed or aftermarket?

Floberg: We’ll do both. We are often called by the distributor — say, Volvo or Hitachi or Kobelco — to install an integrated system.