Lidar, camera and infrared: There are many sensors on modern cars. A start-up has developed a technique to keep these sensors clean.
Anyone who frequently drives modern cars knows warnings like: "Caution, distance radar/blind spot assistant not active, camera/radar dirty!". Because correct data from cameras, infrared cameras and lidar systems (light detection and ranging - optical distance and speed measurement) are the prerequisite for the perfect functioning of the assistance systems, which already enable semi-autonomous driving. Later, it should even be possible to drive fully autonomously according to the highest level of autonomy, Level 5. Dirty sensors are one of the more banal problems on the way to fully autonomous driving. But the simpler the problem, the more challenging it is sometimes to find a reliable solution. With ActaJet, the US start-up Actasys has now developed a system for efficient sensor cleaning.
Precise air jet
Actasys is located in the New York district of Brooklyn, his boss Miles Flamenbaum also traveled a lot between the German car metropolises of Munich and Stuttgart during the development work. He commuted by train and when we talked to him he was really happy about how well and how fast the connection worked – it was much better than the US rail system. From a German point of view, one might hope that he would not be satisfied with the reliability of the railway in his system.
Flamenbaum is currently promoting the ActaJet sensor cleaning system developed by Actasys, the basic principle of which is based on a powerful jet of air pressure. If too many raindrops stick to a sensor, the cleaner blows them away through its air pressure nozzles. When there is snow and ice on the sensor, Actasys uses hot air through the same nozzle, and when mud and mud cloud the sensor's view, the compressed air is mixed with water.
Piezoelectric bellows
The technical basis of the Actasys cleaning system is an actuator cartridge, which in this case consists of piezoelectrically driven bellows. Thanks to the high-frequency suction and expulsion of air, it generates a powerful and constant air flow - rotary fans or pumps are not necessary. The disk-shaped bellows are only a few millimeters thick and slightly smaller in diameter than a classic CD. If the sensor detects contamination, this sets the bellows in motion. So far, Actasys has only been demonstrating the prototypes of its bellows with the compressed air function - the developers are still working on the solution with water injection. Flamenbaum describes the problem that arises: If the water gets onto the sensors via conventional windscreen wiper nozzles, the water consumption is around 20 liters on a day with a lot of spray and dirt.Since the car would then have to accommodate large tanks that still have to be refilled frequently, this solution would be impractical for everyday use. With its piezoelectric bellows, however, it can distribute the water much more finely than with windshield wiper nozzles, which significantly reduces water consumption, says Flamenbaum happily. How much water he needs per day, how he wants to store the water and transport it to the nozzles is still in development, which is why Flamenbaum is not revealing any details.
Cleanliness detection
In the first laboratory demonstrations of the compressed air function, the ActaJet cleaning system is already working well: the nozzles blow the sensor surfaces clean with pinpoint accuracy and with little noise. It is noticeable that raindrops have a negative effect on all sensors, but the infrared camera in particular produces hardly any usable images. The specialists have also developed a method to find out when the sensors are clean again - this was considered one of the major challenges.
Car manufacturers and investors involved
Actasys estimates the market volume for sensor cleaning systems at around 80 billion dollars (currently the equivalent of around 71 billion euros) by 2030, with 630 million lidar systems alone expected to be sold by that time. According to its own statements, the start-up is already working with major car manufacturers – the investors include the Volvo Cars Tech Fund. Major component suppliers (Tier 1/Level 1) and Israeli venture capital firm Next Gear Ventures, which specializes in intelligent mobility, are also expected to be on board. In the next step, Actasys would like to further refine the control systems of its ActaJet cleaning system, for example by including data on weather conditions and fleet usage. However, Actasys has not yet announced a specific market launch date.
Conclusion
Partially or fully autonomous driving and perfectly functioning sensors are inextricably linked - without correctly working sensors, autonomous driving would not be possible. Sensors contaminated by rain, dirt or snow are among the greater challenges in non-ideal environmental conditions.
Actasys from New York has now developed ActaJet, a compressed air cleaning system for many types of sensors. During demonstrations, this system cleans water droplets from sensors with pinpoint accuracy – thanks to compressed air generated by small bellows. Heated air is used for snow and ice, and a small amount of water should be mixed with the air for dirt and mud.
The technology is already well developed. The market for sensor cleaning technology is likely to be huge - with each generation, the vehicles master more semi-autonomous capabilities.If Actasys brings its technology to market maturity, one of the fundamental problems for autonomous driving would be solved.
