Current dark exterior vehicle paint colors can impede lidar signal transmission. BASF technology specialists are developing near-infrared reflective dark automotive exterior paint colors that are lidar compatible. (BASF)
The sensing technologies needed for automated-driving vehicles are evolving as the industry moves toward a high-level (SAE Level 4-5) self-driving vehicle. Sensing technologies already assist with adaptive cruise control, park assist, lane centering, and other driver duties. But in order to meet the needs of high-level and conditional-autonomy, sensors will need a technology-assist. Materials-science specialist BASF is enhancing the understanding of what materials may aid the sensing equation.
“Each step of autonomous driving requires more sophistication and more surety that the sensing data is correct,” said Mark Minnichelli, Director of Technical Development for Performance Materials at BASF Corporation.
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Signal integrity is mandatory in order for the sensing signal to be sent and received, according to Dalia Naamani-Goldman, BASF’s Market Segment Manager for Transportation Performance Materials. “On the radar side, we have transparent materials and are developing an absorptive material that can be used on the sensor surface, housing, and mounts,” Naamani-Goldman said, noting the material is being tuned to function between 70-90 GHz.
A non-variable production process is crucial. “There is speculation in the industry that the frequency requirement could go up to 150 GHz. So if there is a shift in the frequency requirement that the material must function in, we’ll need to look at different additive packages, as well as determine what filler content will be added to the virgin polymer,” said Naamani-Goldman.
Sensing clarity is another autonomous driving must-have.
Whether the sensor is radar, lidar, or even a yet-to-be-developed technology, the autonomous vehicle needs to see the vehicles, objects, pedestrians, and infrastructure. “So having vehicle surfaces that can stay cleaner, longer, or that can self-clean and also maintain the requirements for transparency of signal are very important,” said Minnichelli. One future solution being investigated at BASF involves plastic parts, such as the fascia concealing a sensor lens. “We’re working to come up with a part that right out of the mold has a surface that is easier to keep clean,” said Minnichelli.
The exterior color of an autonomous vehicle can be especially troublesome for a lidar sensor, said Donald Campbell, BASF’s Research and Development Manager. “A dark color can interfere with the signal reflection because the color absorbs the signal and doesn’t reflect the signal back,” said Campbell. He added that BASF is developing metallic silver colors that are friendlier to lidar and radar.
Without fail, every autonomous vehicle needs to sense its surroundings. “Anyone who wears eyeglasses keeps the glasses clean because it’s easier to see. The same is true for autonomous vehicles. The car has to see everything around it, so its vision can’t be impaired,” Minnichelli said.
Kami Buchholz is a contributing writer at SAE International.