Avantel - Trilobite

Avantel has worked with Electrolux for many years in the area of electronic design. In 1995 the project started that would later result in the first real robotic vacuum cleaner for domestic use, the Trilobite^®. We helped Electrolux to design the electronic hardware and software in the first prototype. It was presented around the world in 1997 and generated an enormous interest. The decision was taken to start the development of a robot for serial production. The circular shape and design that resembles a prehistoric trilobite was kept but the electronic and mechanical design was to be refined and made fit for manufacturing. We were very honoured to be put in charge of the electronic design this time as well. An intensive work period followed, filled with technological goodies, creative solutions and a lot of fun.

The challenge
Where do you find the greatest difficulties in designing an automatic vacuum cleaner for domestic use? One major challenge is that there are so many aspects to consider and fulfil.

Maybe the most important aspect is that the robot must not give the impression of being too high-tech and complicated. It must make you feel comfortable, be easy to use and fit in as a “member of the family”. It has to be completely safe to turn loose in your home, where it must be able to navigate around all types of rooms and furniture and make a map of the surroundings all by itself. It should of course be good-looking and as small as possible, but on the other hand be as big as possible on the inside to be able to contain the dust and vacuum effectively. It has to be totally reliable and, of course, it must not cost too much to produce!

The development

The design phase of the Trilobite project was very intensive and great fun. The creativity was flowing and plenty of new solutions and innovations were made. Much of the design work was also dedicated to quality and security assessment and compliance. Throughout the project co-operation was very close between the mechanical designers and vacuum cleaning experts at Electrolux and the electronic hardware and software designers at Avantel.

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The solution

The development process resulted in a compact, tailor-made electronic circuit board together with very advanced embedded software. The circuit board handles all functions of the robot, from motor control and basic operation, like charging the batteries, to sonar management and navigation. Thus the high motor currents and the very small sonar signals are confined within a very narrow space. Signal integrity and EMC design are a couple of Avantel’s specialities, and the circuit board design was made with the utmost care.

The Software

The efficiency and versatility of the embedded software is a small miracle. One major task was to receive and process, the signals from the unique, patented ultrasound sonar, which was developed within the project and acts as the “eyes” of the Trilobite. The software uses the output of the signal processing to detect obstacles and navigate in the room. In addition the machine is equipped with a touch sensitive bumper as an extra safety device, also handled by the software.

Trilobite is equipped with nickel metal-hydride batteries, and when the batteries need a refill the software makes sure the robot goes back to its charging station and then monitors the recharging. To seal off areas where the robot is not allowed (e.g. a staircase) a magnetic strip can be used. Sensors on the circuit board sense the magnetic field and the software ensures that the wheels never pass the magnetic strip.

Production tests and self-tests are embedded and the robot does a thorough health check every time it is powered up. The product as a whole is the result of a very close integration of the mechanical and electronical parts. Every single detail is vital for the complete unit to work.

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