Unmanned Systems Technology 016 | Hydromea Vertex AUV | Power management systems | Unmanned Space Vehicles | Continental CD-155 turbodiesel | Swift 020 UAV | ECUs | DSEI 2017 Show report

October/November 2017 | Unmanned Systems Technology 28 Dossier | Hydromea Vertex AUV algorithms that use only a minimal amount of information exchange and still work. “Distributed systems certainly have some advantage though, because each vehicle receives information from the outside and makes a local decision about what to do.” He likens a swarm of Vertex AUVs to a flock of birds. There is no central controller with a ‘God’s eye’ view to direct each bird; instead they observe what’s happening around them and follow a few simple rules. “It’s enough to watch what your neighbours are doing, so you only need fairly short-range detection and comms with them, and they coordinate with their neighbours and so on. You design the whole system so that it converges to a global behaviour. “For example, a bird at one end of a swarm cannot see another bird at the other end, but still they stay together and don’t run into each other, and they do what they want to do in the end, which is maintain a coherent group. “We don’t just look at acoustics, we also look at the electromagnetic spectrum – with its limitations – optically and so on for very short-range links over a couple of metres, but then with much higher bandwidth. “Our vehicles are fairly close together anyway so we don’t need to put out that much power. We only want to talk to our direct neighbours, and we don’t necessarily want to talk back to the ship at the surface. We don’t assume that we have constant comms with the operators. “So that’s the philosophy. Also, operationally we don’t want to have people babysitting the robots. Our goal is to have more robots than people, that two people can run ten or 20 robots,” Schill says. Optical alternative Optics provide an alternative for high- rate, short-range comms, and Hydromea has developed an optical modem that, like the DDTs, it sells separately as a spin-off from the Vertex programme. The company has sold a few and counts Germany’s Alfred Wegener Institute among its customers, which has put it to use in vehicles deployed from the research vessel Polarstern . Marketed as the Luma 250LP, this ‘ultra-efficient’ modem is potted in transparent plastic in a block measuring 100 x 50 x 30 mm. It weighs 250 g in air or 50 g in water and offers a maximum range of 7 m with data rates of up to 250 kbit/s or 600 kbit/s at reduced range. Software features include error detection, forward error correction and automatic wake-up from sleep mode. When the Vertex is on the surface, the operator at the control station communicates with it over an 868 MHz radio link operating in a band for which no licence is required. The control station end of the link is a box that plugs into the laptop running Hydromea’s proprietary mission management software, while at the AUV end it is integrated into the navigation module and fed by an internal antenna. This radio link is another subsystem that Hydromea built from commercially available components. Hydromea can integrate the Luma 250LP optical modem it has developed into the Vertex for high data-rate comms over short distances (Courtesy of Hydromea) Hydromea essentially designed Vertex around YSI’s EXO 2 multi- sensor water sampling sonde, removing its battery and integrating it into their in-house electronics stack (Courtesy of Hydromea)