Uncrewed Systems Technology 043 l Auve Tech Iseauto taxi l Charging focus l Advanced Navigation Hydrus l UGVs insight l MVVS 116 l Windracers ULTRA l CES 2022 show report l ECUs focus I Distant Imagery

36 our future hydrogen-powered Iseautos, it will depend on scale considerations. Producing large quantities of PEMFCs needs large-scale automation: Toyota for instance have made quite a lot of progress with their fuel cell plant. If this low-temperature PEMFC can be produced at scale, that could be perfect for serving customers in warmer or colder places.” Design and the integration of the hydrogen powertrain – including layout, packaging and programming the fuel cell, the battery and interconnections – took about a year, and ran in tandem with efforts to improve the all- battery powertrain and to redesign and repackage the laboratory-level technology of the low-temperature PEMFC into a larger stack of cells capable of outputting the 5 kW of power needed to run the Iseauto. “We also switched to lower voltages in the battery pack and e-motor, down to 48 V, because converting the low-voltage fuel cell’s output to a 300 V battery system isn’t smart from an efficiency standpoint, it’s an unnecessarily huge conversion of power that causes way more current losses than just using a 48 V bus for propulsion,” Mossov adds. Computer network Meanwhile, the onboard computer systems and cabin systems run on a 12 V bus, provided via a DC-DC converter. A main computer unit monitors the navigation, performance and health inputs from all the Iseauto’s high- and low-voltage systems, while outputting commands to the battery, inverter, doors and lights. “Then we have a main electronic controller, which constantly checks that the main computer is still working or that the other electronic controllers are still sending signals correctly,” Mossov says. “That middle layer is our key safety system – if something is detected as off, it’s this controller that gives the final command to make a full stop.” These other ECUs include the steering controller, the brake controller and the energy systems’ controllers. “We tend to use fairly regular COTS processors and controllers,” Mossov says. “Most of the work is in the physical, environmental and thermal management, because we can’t have humidity or vibration getting into them, we need them to last. “Luckily though we’ve seen more and more motherboards coming out with just 12 V inputs, which we can use to keep our computer systems simple. Also, there’s going to be a lot more hardware to choose from as more companies get into manufacturing silicon – I don’t think we’ve made more than three Iseautos with identical computer architectures, simply because it’s been so hard over the past few years to bulk-buy identical computer parts.” The computer software stack runs on April/May 2022 | Unmanned Systems Technology By running on hydrogen power from a low-temperature fuel cell, Auve Tech hopes its taxis will operate in very cold (or very hot) climates without long warm-up times We have a main electronic controller which constantly checks that the other electronic controllers are still sending their signals correctly