Trombia gives street sweepers the autonomous treatment

Professional Engineering

The Trombia Free autonomous street sweeper
The Trombia Free autonomous street sweeper

Autonomy is coming to the roads, whether you like it or not.

Tesla drivers in the US regularly make the most of their cars’ autopilot mode, while the UK government plans to enable some autonomous operation in motorway traffic. 

How many drivers will regularly use the features remains to be seen, as does the eventual level of acceptance and uptake of fully driverless cars, but drivers will have to come around to the idea that not all of their fellow motorists are human. 

Pedestrians and cyclists have not had to make similar concessions – but that might be about to change. Finnish firm Trombia recently announced the first commercial pilot programme of the Free, an electric and fully autonomous street sweeper. The first project is cleaning bike paths in the city of Espoo, while pre-sales for Norway and Germany will start this summer. 

The machine is a slick, sci-fi style solution to an issue that might not seem immediately obvious. Will it be crossing our paths before long? 

Nordic spring

The Free is the size of a small car. At 2.3m wide, 1.5m tall and 3.52m long, it weighs 2,600kg when empty. It has a 45.6kW/h battery for four hours of autonomous high-power street cleaning, which doubles with an extra battery. Standard charge time is five hours with a high-power plug, or 15 with a 230V mains plug. The machine can sweep pavements at 1-6km/h. 

Targeted at the dusty ‘Nordic spring’, when gritting sand starts to be ground into fine dust, the autonomous sweeper uses a combination of mechanical removal, brooms and cyclonic technology to remove up to 96% of PM2.5 and PM10 particles from the ground. 

The sweeper’s machine vision uses a lidar-based point-cloud system, combined with advanced algorithms and localisation capability to operate in all weather and lighting conditions. Trombia says it can clean 5,000-15,000m2 per hour. 

The project’s main target, however, is energy efficiency. The firm claims its sweeping technology uses 85% less energy and 95% less water than conventional suction sweeper technology, and it can reportedly save 32.5kg of CO2 emissions per 1,000m2 cleaned compared to diesel-fuelled alternatives. “The only way to combat the over 3m CO2 tonnes that street sweepers around the world cause is to change to a greener and more power-efficient option,” Trombia claims. 

The company’s pilot programme targets ports, car parks and ‘smart city’ projects, so it could be a while before we see the sweeper on the winding and irregular paths of patchwork cities like London. A great deal of faith will also be needed in the vehicle’s autonomy and vision systems before it is used in areas dense with pedestrians and cyclists, and the myriad other obstacles found in busy urban areas. 

Multi-purpose use

Ultimately, the Trombia Free could become more than just a street sweeper. The device uses an in-house command and operations system, which the firm says will enable ‘agile and straightforward’ upgrades. New features could include digital-twin recording, which would enable better operation, or air quality measurement.

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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.


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