‘robot one video’, ‘robot one odometry’. In DDS, you would have to enumerate all these, one by one. Zenoh figures out that they all belong to the set called robot one ‘star star’ and tells you ‘if you’re looking for something for robot one ‘star star’, just come to me’,” Corsaro says. The same method is used in routing, he says, comparing it with route planning for driving, which starts by simply identifying a few major roads, with all the detail in the last two or three miles before the destination. In this analogy, DDS would give the driver every turn-by-turn instruction at once, subjecting them to information overload. While input-output (IO) is responsible for the lion’s share of energy consumption within an operating system such as ROS, communication incurs a large share of the operating costs of a network of robots, so a more efficient protocol saves both energy and money. Talking directly Corsaro says there are three aspects that really matter: how efficiently the protocol uses the CPU, wire efficiency and routing efficiency. To improve the latter, Zenoh allows two robots on the same network to communicate directly, peer-to-peer, while others, such as MQTT, require them to go via the cloud. Because Zenoh messages are so small, compared with DDS messages, with overhead of 5 bytes for an individual message, communication costs are much lower. Further, when sending data more frequently, it can be packaged more efficiently, so the overhead drops to 3 bytes per megabyte. DDS imposes a minimum of 568 bytes. In a comparison of communication costs over a satellite link, Corsaro assumes 24/7 communication over a year and relatively small payload packets, resulting in 1.8 GB of overhead with DDS and 157 MB with Zenoh, and respective costs of $14,400 and $1200. In a 2022 study, Open Robotics assessed about 28 protocols as candidates to replace DDS as the communications middleware in ROS 2, followed by a poll of ROS users. Zenoh came out on top. Late last year, it was announced that the next long-term release of ROS 2 would run its communications on Zenoh. It has also been selected by the European initiative on software-defined vehicles, known as Eclipse SDV. “You can think of protocols as being like the nervous system of the body, and I want to make our protocols the nervous system of robotics and automotive,” Corsaro says. “The team is super committed to making that happen. We really see it as our mission.” 23 Uncrewed Systems Technology | February/March 2024 Angelo Corsaro, 48, describes himself as a Sicilian “by blood”, even though he was born in Bergamo, a town close to Milan and Lake Como in Northern Italy, where his father worked after graduating. When he was aged six or seven, his parents returned with him to Catania in Sicily to care for his ailing grandmother, to whom he became very close. Corsaro’s grandparents lost almost everything during the Second World War, and he credits their efforts to rebuild the family’s fortunes with instilling a strong work ethic in him. Growing up in Catania, Corsaro discovered a talent for maths and physics at school, got into computer science at an early age, and also took up music. He remains a bass player. Until he sustained a serious injury at 17, he played football at a high level. “I never thought that I was going to be a football player because I really wanted to be an engineer,” he recalls. He regards the timing of the injury as fortunate, as it allowed him to focus more on his studies when he went to university in Catania to study for a degree in telecoms engineering, which he followed with a master’s in computer engineering from the same institution, and then a PhD in computer science from Washington University in St Louis, USA. Sicily has a strong physics tradition, and early 20th-century theoretical physicist Ettore Majorana is among Corsaro’s heroes. “He was born two blocks away from my grandmother’s house.” While regarding himself as temperamentally unsuited to being mentored, Corsaro expresses great admiration for his PhD advisers Doug Schmidt and Ron Citron, and his late calculus professor, Filippo Clarenza. A career in software followed at companies including Selex, PrismTech and Adlink Technology, overlapping with work at the not-for-profit Object Management Group Standards Development Organisation (OMG SDO), where he served on the board of directors. He started ZettaScale Technology in January 2022. Angelo Corsaro
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