50 followed the soldiers autonomously and was then loaded with a marine playing the part of a casualty they came upon, and one where there was an assembly area where the UGVs were held in reserve,” Tremblay says. “In the latter, troops in a forward position encountered a casualty actor as part of the exercise, and they radioed their rear echelon [the portion of a military force tasked with administrative and supply duties] to activate and program a UGV to go and meet them at their GNSS position. “And there’s a third instance where a Mission Master has been left behind, say, for ISR purposes, as if to watch a given area for signs of enemy activity, where if you’re still within radio range of it, then you can requisition the UGV yourself to come and meet you.” Tremblay adds that, from a technical point of view, performing Medevacs is not difficult so long as the UGV in use has a form factor and intelligence conducive to negotiating the types of obstacles to be encountered in a fully autonomous way. For instance, if the mission environment is a devastated urban area, with heavy rubble and collapsed buildings, the CXT and XT UGVs are likely to be the best choice for their robust ability to push a pathway through to where casualties are located. “One day, we might investigate the use of robotic arms to even pick up casualties and place them atop the flatbed of the UGVs in an autonomous way. It’s certainly possible. But that raises issues on how best to physically stabilise the wounded and related mechanical challenges, which will take time to solve,” he says. Preferred methods In Australia, the USMC’s preferred method of using the Mission Master was to first have a medic on hand to stabilise the casualty, after which two or three soldiers would lift them on to the back of the UGV. Then the UGV would be ordered via GCS to find its way to a specified casualty collection point autonomously. A seat would be installed for the medic to sit inside the vehicle and observe the casualties, and to perform first aid or other stabilising activities if the need arose. A hook for bags of intravenous fluid was also installed. The activities of the Estonian authorities were similar, with the addition of testing the ability of the UGVs to travel through forested areas. This included the detection of overhanging branches and knowing whether the vehicle could drive safely under or through them without operator intervention, intelligently keeping to a dirt trail, and navigating through large fields of tall grass without losing its sense of direction. “That’s another big reason [why] these sorts of trials are so valuable: we get to learn the edge-case limitations of our systems and refine our development roadmap,” Tremblay says. “We’ve been doing that continuously with the UK Ministry of Defence (MoD) for over three years now, with great interactions and feedback from them that have helped improve the systems a lot.” Diniz adds: “We’re starting similar trials in Norway, where there’s a lot of very difficult terrain for autonomous systems to deal with, and our team is using the XT to compete with others there now. And in 2023, the Finnish MoD carried out trials in the Arctic Circle, where we were the only ones who accepted the challenge of working autonomously in that environment.” Real and virtual worlds The UGV is typically set to run no faster than 20 kph while carrying casualties to keep them physically stable and preserve their health (particularly when offroad), and also to ensure the autonomy software stack is never overwhelmed with sensory inputs faster than it can process them into logical steering, braking and speed commands. However, Rheinmetall Canada reports that the current target for further optimisation of the autonomous Medevac capability is to increase the nominal speed at which casualties can be autonomously evacuated. “This is something all UGV manufacturers interested in Medevac are struggling with,” Tremblay explains. “There are many platforms that can go up to 70 kph now, but not in a fully autonomous way. Computing power and AI today don’t guarantee that a UGV moving at 70 kph can still differentiate between a rock and a bush, or between a wall and a fence.” Speed is of the essence This is why Rheinmetall is focused on increasing the speed at which its vehicles can run fully autonomously, as are other UGV organisations, such as Team PoliMOVE of the Indy Autonomous Challenge – explored in depth in issue 46 February/March 2024 | Uncrewed Systems Technology In Australia, the US marines trialled both switching the Mission Masters from mule to medevac in the field and summoning the UGVs from a base out to a casualty’s location
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