Robots at home alone

Vacuum cleaning? Lawn mowing? Nowadays, that is done by robots: automatically, quietly, reliably and without grumbling

Look who’s mowing the lawn, ask the neighbours as the Automower® glides across the lawn, as if by magic. The blades of grass are cut to size all over, apparently without any recognisable pattern. At the same time, a flat, prehistoric-looking creature is crawling over the parquet and carpets. The Trilobite leaves nothing but a dust-free floor behind as it makes its way through the apartment. Household robots are playing an ever greater role in relieving us of our chores in house and garden. This is made possible by EC technology.

High performance in a small space

An extinct arthropod from prehistoric times inspired Electrolux to develop the world’s first fully automatic vacuum cleaner, the Trilobite, at the turn of the millennium. Flat and as nimble as its prehistoric namesake, the robotic vacuum cleaner glides over the floor without colliding with anything. The fact that the floor is then sparklingly clean is made possible in part by ebm-papst.
Electrolux developed the blower sections itself. Then the Swedish household appliance specialists needed a motor to match, a motor that could satisfy the rigorous demands on the aspirator, and which was also cost-effective. “The limited space meant that the required air performance could only be achieved by using a high speed,” explains Achim Labitzke, Product Manager at ebm-papst in St. Georgen. However, for reasons of cost, only a single-phase Variodrive motor was possible. This is usually employed in compact fans with a power draw of ten watts. Now it should draw 55 watts at 18 volts to generate a speed of up to 18,000 rpm. “We reconciled the cost aspect and the power requirement by optimising the motor output and developed a powerful suction drive,” explains Labitzke.
Optimised efficiency is essential for good battery performance. After all, the suction drive uses two thirds of the Trilobite’s energy. The single-phase EC motor achieves an efficiency of
75 percent despite the high speed. This creates an overall efficiency of 45 percent for the blower. That is some 10 percentage points more than a mains-powered vacuum cleaner. And despite this extreme mechanical load, the blower motor has a service life of more than 2,000 hours.
Moreover, the EC motor is by its very nature quiet. To enable the complete blower to have a maximum noise level of 75 decibels, additional acoustic optimisations were performed in St. Georgen. Now, the fully automatic vacuum cleaner buzzes through the apartment without disturbing anybody talking on the phone or watching TV.

The pioneer of robotic vacuum cleaners. The Trilobite works out the most efficient way of cleaning a room. It uses ultrasonic waves to detect and circumvent obstacles. If used regularly, it will reduce manual vacuuming to about once a month.

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