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

104 While reading documentation and release notes is naturally vital to a basic understanding of the principles of an ECU, beyond these, programming technicians are using SDKs more often in order to write their own ECU software, to incorporate their own modules, analytics and safety behaviours. As aviation regulations and certification requirements evolve to account for heavy UAVs and urban air mobility vehicles, open SDKs for ECUs could become critical requirements for designing autonomous systems to obey new air traffic laws. Opening the ECUs in data terms is also essential for professional users who are conscious of maintenance costs and potential accidents that could increase markedly as a result of inaccurate record-keeping of the hours logged by each component in the powertrain. As a result, not only do many ECU interfaces now have dedicated logbooks, smart functions such as automatic booking of hours on each part (paired with alerts when 100 hours or an end-of- life figure are reached for a component) are becoming more common among many ECU developers. Some basic tracking of engine wear information has long been available in ECUs, with parameters such as engine runtime being especially easy to find. On top of that, some ECUs will now also keep a running total of crank revolutions, a record of engine temperature peaks over time, the amount of time spent running at high temperatures above certain thresholds and at high loads, and others, simply by using data amassed from sensors already commonly installed on the engines. Maintenance managers can use these to make more informed and more timely maintenance decisions. For example, they could schedule an alert for a change of cylinder heads after running for a specific number of hours at high temperature, or a change of bearings tied to a certain number of crank revolutions, along with other factors such as running with a high oil temperature for too long. As well as using these for informing in-house technicians, they could one day be critical for liability discussions, so that end-users can prove that all parts were up to date, or for analytics to see which parts are being replaced more often – and hence perhaps being pushed too hard or misused – and theoretically where replacement costs should be saved or redistributed. Manufacturing and componentry With ECU designs remaining quite stable nowadays, most changes to manufacturing layouts are iterative – minor evolutions rather than anything major or revolutionary. For instance, some manufacturers have installed independent power supplies for their ECUs’ SD cards, after discovering that faulty cards can short-circuit their CPUs’ power supply connections. Also, some are changing their method of temperature sensing, going from using current drivers to a network of resistors, to expand the types of sensors that can be connected to the ECU. One of the most common variations in manufacturing concerns connectors. Many customers will want different pin layouts, locations and form factors to enable their ECU board to stack as an OEM device inside a motherboard (or similar) of their own. No connector type in particular yet stands out in terms of demand. Most custom products for small UAVs will be released with numerous 5 V interfaces for PWM-controlled servos, or with 12 V interfaces for larger craft with bigger April/May 2022 | Unmanned Systems Technology Focus | ECUs Connectors tend to be the most changed item between batches of ECUs, to suit different customers’ power and form factor requirements for example (Courtesy of Power4Flight) Fuel cell control units have very different engineering requirements from ECUs, owing to the higher EMI, lower vibration and other environmental factors that must be accounted for (Courtesy of Northwest UAV) Not only do many ECU interfaces now have dedicated logbooks but smart functions such as automatic booking of hours on parts paired with alerts