Inside Unmanned Systems

DEC 2018 - JAN 2019

Inside Unmanned Systems provides actionable business intelligence to decision-makers and influencers operating within the global UAS community. Features include analysis of key technologies, policy/regulatory developments and new product design.

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GROUND SENSOR RESEARCH 42  December 2018/January 2019 unmanned systems inside solve the problem of autonomous navi- gation using sound like bats do." SOUND AND VISION This echolocation research could benefit "any robot that needs to navi- gate—that is, most robots," Eliakim said. This includes, he added, vacuum cleaner robots that need to maneuver around liv ing rooms, agricultural robots navigating greenhouses and rescue robots threading their way through a collapsed building after an earthquake. Unmanned systems such as driver- less cars often navigate with the aid of LiDAR, which bounces light pulses off obstacles just as echolocation bounces ultrasonic signals. Eliakim noted a Robat-like approach might have a number of advantages over LiDAR. To begin with, fog, smoke and glare can prove troublesome for LiDAR just as they do for eyes or visual sensors. Sonar can scan right through such challenges, Eliakim said. In addition, LiDAR emits far more pulses than ultrasound. "This means LiDAR has a lot more data to churn, and requires a lot more computing power, which is a real disadvantage," said Rolf Mueller, a professor of me- chanical engineering at Virginia Tech. Mueller has also investigated bat echolocation and its possible uses for drones, although he did not work with Eliakim and his colleagues on this project. LiDA R a lso can be ex pensive, Mueller said. In comparison, "we can develop our sensing unit for under $15," Eliakim said. Furthermore, many LiDAR systems that cost less than $100, such as those used in robotic vacuum cleaners, rely on 740-nanometer near-red wave- lengths of light, Eliakim said. This is a big problem when working outdoors where ref lected sunlight can lead to many inaccurate readings, making such systems "almost unusable in the daytime," he explained. One of the biggest problems LiDAR faces is images ref lected off mirrors and glass. LiDAR can mistake ref lec- tions for real objects, or it can fail to recognize mirrors and windows as solid surfaces instead of open spaces. A Robat-like system would not have this problem, Eliakim said. Still, ultrasound can have problems with ref lected sound. For example, if a drone equipped w ith ultrasound were to approach a f lat wall at a very shallow angle, "the ultrasound would get ref lected off that wall in such a The Robat was equipped with an ultrasonic speaker that imitated a bat's mouth and two ultrasonic microphones that mimicked bat ears.

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