USE Network launch I UAV Works VALAQ l Cable harnesses l USVs insight l Xponential 2020 update l MARIN AUV l Suter Industries TOA 288 l Vitirover l AI systems l Vtrus ABI

36 A s unmanned vehicles are put to different kinds of work in the air, on the ground and in the sea, they are being designed to incorporate a growing number of connections. Road vehicles, and UAVs for first responders or heavy-lift applications in particular, have to integrate an array of sensors, power systems and electric motors to ensure safe navigation, and intelligent detection, as well as speed of travel, comms and processing. Interconnecting these various subsystems is achieved using cable harnesses, which provide fast and reliable links for power and data without taking up too much space or weight in the vehicle’s interior. Fortunately, in recent years cable harnesses have become lighter, smaller, better insulated and capable of higher data and power throughput. These improvements are thanks to new innovations in the cable industry, as well as gradual improvements in production machinery, skills and engineering rigour. A typical cable harness consists of several different parts – a conductor wire (or several of them) at the centre, with layers of insulation around each wire and a thicker jacket of insulation around groups of wires for protection against environmental or physical damage, along with shielding for EMI protection. Each of these parts bears close examination, as do some alternatives to conventional harnesses that are gaining traction in the unmanned sector. Insulation The choice of insulation materials, at the individual wire level and regarding the outermost cable jacketing, should be prioritised when considering harness options. As UAVs pack more and more power inside their hulls, their cabling will increasingly be subjected to damage from thermal expansion and contraction, whether it be heat from engines and electronics or the cold of high altitudes or polar regions. As well as the temperature outside an unmanned vehicle, there will also be concerns about moisture and dust damaging conductors. The use of UAVs in maritime survey and desert flight trials for example is a case in point here. The growing use of ICE, hybrid or high- voltage battery powertrains also means that as well as fears over cables being doused in water, other potentially harmful substances such as gasoline, lubricant oil and battery fumes will increasingly be coming into contact with harnesses. These considerations must also deal with the fact that cable harnesses inside UAVs are often twisting and bending throughout a maze of hot components with sharp corners that dig and cut into their outer insulations with each vibration or slight shock. With repeated deployments, structural weaknesses can occur at key points in cables over time. Insulation materials can be made thicker to add more protection, but that reduces their flexibility and thus makes it harder to bend and twist them throughout the crowded componentry inside a UAV’s chassis. Advances in cabling systems continue to track the growth in the demands placed on them. Rory Jackson examines the key options Fresh connections June/July 2020 | Unmanned Systems Technology With some autonomous systems now carrying thousands of connections, robust and precisely engineered cable harnesses are essential (Courtesy of St Cross Electronics)