Testing Robotic Cleanup on a Construction Site

A group of people had gathered at a construction site in Vantaa, Finland, on February 25, 2019. On the floor of a large room, a robot was blinking lights, apparently waiting for instructions on what to do next. This was the first test of an industry-grade cleaning robot for construction sites.

The test was the culmination of an experimental project that NCC started in May 2018. Its goal was to develop an automated solution for keeping a construction site clear of dust, which is a big problem and potential hazard for workers and equipment.

Present at the Murata Electronics’ factory extension site were representatives of four organizations: NCC, Pulurobotics, Palmia, and the Department of Computer Science at the University of Helsinki. Each one of them had a specific role in the project.

Kimmo Kärkkäinen, NCC’s project manager, had seen in his earlier projects how inefficient cleaning could be. “It has been frustrating to see how a person cleans a half-hectare hall manually with a big broom,” he says. “There are small vacuum robots and ride-on sweepers, but I’ve not seen a robot of this size and with such capabilities before being used for cleaning.”

When NCC learned about what Pulurobotics had already done in robotics, they decided to start a KIRA-digi experiment with them. KIRA-digi is a national project that advances digitization of the built environment by funding fast trials. Palmia joined in as a provider of cleaning services and the University of Helsinki as a user interface development partner.

The Robot That Can Maneuver Autonomously

“Pulurobotics started out as a solution to a very tangible problem,” says Miika Oja, a cofounder. “We have a warehouse in Tampere that needed a telepresence robot. In 2016, none existed that could survive the uneven floors and obstacles in the space. Arno Munukka and I developed the first prototype. It was not perfect until we ran into Antti Alhonen, a programmer who could help it become autonomous.”

The prototype that was under scrutiny at the Murata site is the 12th version. It is the size of a 600 x400 DIN box, lying flat on four wheels. It has ten sensors on its sides, indicator lights in each, and a vacuum cleaner on top of the body. In front, there’s a wide nozzle for the vacuum.

As the robot moves around the room, it cleans the dust from the floor very well. You can clearly distinguish where it has been by the spotless streaks in the otherwise dusty areas. If the robot detects a person or an object in its path, it will stop immediately and try to go around the barrier. The sensors can “see” in three dimensions, covering 360 degrees horizontally and 110 degrees vertically.

The prototype’s vacuum cleaner is a €65 appliance that is not optimized for battery use. That’s why it exhausts the 1.3-kWh battery in under two hours. Without the power-hungry tool, the robot could drive for days, carrying a 110-kilogram load.

Mechatronics and Software Make a Robot

Building a robot is a cross-disciplinary endeavor. Pulurobotics got help from the airplane industry to rivet the aluminum body. They developed a motherboard that has all the electronics in one unit. They developed unique ToF (time of flight) sensors that use visible and infrared light to map out the environment. Even psychologists gave tips on how to make the robot interact with humans.

“The biggest challenge in the project was the mapping software. The device can scan the space accurately but combining the scans into a coherent model is still difficult,” Antti Alhonen admits. As a result, the floorplan of the scan is slightly skewed on Alhonen’s laptop screen. Using BIM as a reference could solve the problem.

The robot’s software has around 40,000 lines of code. In addition, the team of the University of Helsinki developed an interface for setting up the cleaning areas. Their software tells the robot how to cover an area efficiently. The robot receives instructions and sends back data via Wi-Fi. It could as well be a 3G/4G connection that makes remote operation possible.

A Robot as a Platform

Cleaning is just one of the many uses for the robot. Harri Luuppala, chairman of the Pulurobotics board, explains, “Instead of developing a robot for a specific use, we decided to build a robotic platform on top of which you can add any application or functionality.”

The project team has already come up with many ideas. The robot could have an arm that can lift things up and move them around. For example, it could stack furniture before cleaning and place it back afterwards. It could also rearrange items in a room to change the layout.

The robot could be a personal helper on a construction site, following a craftsperson and carrying the tools. With cameras attached, the robot can photogrammetrically scan spaces and create as-built documentation of the site. At nighttime, it could serve as a security guard.

The Robotic Future

“A robot like this will improve safety, quality, and efficiency on the site. When the floors are clean, nobody dares to be messy on the premises,” Kärkkäinen says. “We’re definitely looking forward to a finished product from Pulurobotics.”

The provider is ready to take on the challenge. Luuppala mentions that they have already ordered parts for 50 robots. Industrial cleaning robots could be among the first commercial applications of the platform. The price of a robot could end up around €5,000. Robots with similar features typically cost between €30,000 and €50,000.

Fabian Fagerholm is a researcher at the University of Helsinki and speaks enthusiastically about use-inspired research. He thinks that one of the most significant gains of this project has been the network of professionals it has created.

Fagerholm’s team is building a software architecture that serves robotic development. “At a construction site, you’ll need a swarm of robots. They could convene at a command center, download their instructions, and move to their respective locations to do the jobs autonomously,” Fagerholm envisions.

Palmia provides, among others, cleaning services in southern Finland. For them, robotics is a strategic question. “Robots are one of the few ways left to improve a cleaner’s productivity,” says Riku Moisio, the CIO of the company. He believes that today’s consumer grade robots can soon evolve into useful industrial tools. Moisio points out that robots will be very efficient for certain clearly defined functions, but not a panacea that will make humans redundant.

Luuppala says that Pulurobotics has not patented their technology. Their software is open source and can be used at places such as schools that want to develop robots on their platform. Pulurobotics and the KIRA-digi project have shown that you can develop world-class technology without the $100 million funding that competing firms typically have at their disposal.

“Finland is already the land of Linux. We want to make Finland the land of open-source robotics,” Luuppala declares.

For more information about the project, contact Kimmo Kärkkäinen at kimmo.karkkainen(at)ncc.fi.