Uncrewed Systems Technology 044 l Xer Technolgies X12 and X8 l Lidar sensors l Stan UGV l USVs insight l AUVSI Xponential 2022 l Cobra Aero A99H l Accession Class USV l Connectors I Oceanology International 2022

32 more strain – be it from compression, tensile stress, vibration or other issues – higher amounts and quality of fibre were laid up, and the directions of the fibres selected to counteract any directionalities in the strain, without overcompensating and causing torsional stress and additional vibrations. “Advanced modelling is great but will only get you so far, which is why most of our structural r&d consisted of receiving a new hull part design, bench-testing it, identifying where it would break first and how, then iterating something that improved on it, either with more rigidity or less weight and cost,” Skantze says. “We’ve carried out a lot of test flights, and several of the test aircraft have sustained crashes with only minor damage; they are sturdy vehicles. So we’re now happy with the design and functionality of the structure, inside and out, and any further changes we make will be purely to target weight reduction, even sacrificing strength where it’s not needed. It might be OK for some structural things to snap in a crash; better to avoid crashing in the first place using either the parachute or autopilot.” Autopilots The X12 has used various autopilots, both PX4-based and other independents. The clincher for Xer in selecting autopilots has been the ability to communicate engine data to the GCS. “That isn’t as trivial as you would expect, as we discovered in-house,” Skantze says. “We have sensors left and right throughout the power unit for rpm, heat, current, battery charge rate and more, and that data has to be sent to the engine controller and the autopilot, then via the antennas to our computer on the ground running GCS software so we – or the end-user – have full knowledge about the health and response rate of the engine. “As an alternative to PX4-based GCSs we’ve also modified the ground control software by working closely with UgCS to be able to interpret and visualise what’s going on throughout the UAV. That also helped to determine the level of information presented on screen, alerts and availability of remote control step-in options for mission safety and the customer’s sense of security regarding their asset. “We try to build as much autonomy into the UAV as possible. For instance, if the engine runs too hot or suffers certain failures, the X12 will start an emergency- controlled landing sequence, but the user must always feel able to intervene as much as is necessary.” In addition, Xer cites the flexibility, transparency and price of PX4 autopilots as attractive qualities, particularly in terms of changing components ad hoc to meet customer requirements using plug-ins from across the open-source networks. Data signals run between the autopilot, ECU, payload and comms systems using standard CAN and MAVLink protocols, largely carried over COTS 5-12 V connectors and wires, with most of June/July 2022 | Uncrewed Systems Technology Mounted on the two-stroke gasoline engine is a Sullivan Acutronic alternator. The X12’s produces up to 6.5 kW while the X8’s generates 5 kW The X12’s six coaxial motor pairs produce a maximum 15 kW of power in total; the X8’s four pairs output up to 7 kW