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

100 Focus | Connectors As a result, more and more connector companies are building or expanding their own internal testing labs to cater for an end-user base whose testing requirements seem to be on an unwaveringly upward trajectory. One marine connector company has gone as far as developing a pressure test chamber capable of automatically cycling pressure hundreds of times, while incorporating refrigeration and heating systems to simulate cold and hot conditions. That was in response to internal studies that found connector material failures to be more common in warm, tropical environments than in very cold waters. Housing materials and parts To provide a base level of contact protection against environmental variations, a wide variety of metals and plastics for connector shells are available. Their choice depends mainly on the cost and weight constraints that OEMs are dealing with, and knowledge of these is well-established throughout the industry. Of them, it is worth mentioning that PEEK has gained considerable prominence thanks to its chemical resistance, temperature range and low cost, and Ultem is also widely used for its easy machinability. Additive manufacturing has also helped considerably in prototyping plastic as well as metal housings that outwardly take the same form factor as older connector products while fitting more pins or hybrid combinations of power and data contacts inside. These technologies are also well-understood now by connector designers looking to fulfil a request, and customers looking to present one for mass production. Less familiar to many is the wide array of new backshells that connectors can come with. These can provide critical protection against the ingress of dirt, liquids and, most importantly for new generations of autonomous vehicles, EMI. While system integrators typically have a good understanding of the kind of shielding they should have in their cable jackets – for instance, EMI protection has long been critical for safeguarding PWM links running between ESCs and electric motors – they may not understand so well how their new electrical connector designs might be susceptible to (or generate) EMI. Backshells made from combinations of aluminium and steel, with mixtures of elastomers or composites for additional environmental robustness, could be critical add-ons for the new wave of high-current connectors, or for any sensitive data connections sitting near them. In addition, an ever-wider variety of latching methods are available for ensuring mating is secured against shock and vibration. For example, screw- locking enables what is effectively a lengthy interference fit through an outer sleeve on one plug that mates circularly into or around the other. Alternatively, some connectors can be designed with an integral safety locking ring to prevent unauthorised or accidental release. As well as these, many traditional approaches are still available that work well for most applications. For instance, circular connectors are often selected with the familiar push-pull locking. This works by the plug having an outer sleeve with bevelled forward edges that, during mating, catch and are secured in a locking groove inside its receptacle. For some applications, however, excessive mating security can actually be problematic: defence operations where a UAV being recharged or repaired must be quickly redeployed are an example here. For such situations, connectors can instead be designed with breakaway latches that separate when a certain threshold of direct manual pulling force is applied, unlike screw locks that must first be unscrewed and push-pull locks that must be squeezed. Manufacturing innovations As demand for connectors across the autonomous vehicle industry grows, connector manufacturers are constantly looking to upgrade their manufacturing lines with newer and better machinery to enhance the productivity, quality control or complexity of units that can be assembled. While retaining manual production of some aspects can be critical to providing the customisations that uncrewed vehicle makers request, automation provides too much consistency and reduction of man-hours per unit for connector manufacturers not to have viewed it as an upgrade worth investing in for the past several years. Among these are CNC-cutting June/July 2022 | Uncrewed Systems Technology Significant care and investment is going into new techniques and higher standards of connector production (Courtesy of LEMO)