Cable harnesses | Focus These can therefore bond a cable assembly to an airframe or chassis, and keep cables from becoming a disorganised mess with the risk of one cable tugging on another, or hazardous levels of friction occurring between them. These sorts of external fixtures are well-understood and widely available. Gaining popularity however is a range of internally fixtured cable-tie mounts. One new example of these is a type of injection-moulded part produced in Ultem 2400, PEEK and other plastics. As these feature an internal fixture, it replaces the external fixtures used with many cable management products, saving technicians from having to remove the external fixtures when reorganising cables and cable ties. That design aspect makes integration easier, as well as passively applying 20-35 kPA of pressure to the area being bonded. Future of harnesses As discussed, there are a wide range of approaches cable suppliers will take with the various plastics and coppers making up their cable assemblies, and in future these are likely to incorporate an array of technologies such as additive printing for bespoke connectors and cable management solutions. New materials such as foamed plastics are also likely to emerge, which can hugely reduce the weight of cable assemblies across vehicles. However, the biggest shift in cable technology to come within the next decade might stem from manufacturers increasingly developing and offering fibre optic cable assemblies to uncrewed vehicle manufacturers. The high-speed data rates and bandwidth advantages of fibre over copper are well-understood – optical cable transmissions are theoretically only 31% slower than light itself, and could have over 1000 times the bandwidth of an equivalent size of copper cable. On top of that, optical fibre is effectively immune to noise interference, as its laser signals are not disrupted by EM emissions, and it does not emit EMI either. That closed architecture is useful for defence operators and anyone else concerned about data security. So long as decent encryption modules are used in the network, it becomes nigh-on impossible for hostile parties to log what is being communicated across a fibre network, unlike in a copper one. Now, with autonomous vehicle OEMs and fibre cable manufacturers both targeting 100 Gbit/s comms capacities, the former increasingly discusses potential supply capabilities with the latter. Also, the cost of fibre – which in the past was prohibitively high compared with copper – is falling. Although it was around twice the price of copper just a few years ago, their prices have grown much closer thanks to higher manufacturing volumes and r&d into production methods. The growing use of fibre is in turn spurring more interest in active cabling. These are copper-based harnesses for data links that contain integrated circuits in their connectors for mitigating or compensating for attenuation, cross-talk and other problems affecting data fidelity, speed and bandwidth in otherwise ‘passive’ cables, hence improving the overall performance of the harness. Through the signal and fidelityboosting nature of their ICs, active cables can use much less copper than passive cabling for a given set of performance parameters, so potentially they can be far lighter. They can also be made more than twice as long as passive cables with the same end-to-end performance. The drawbacks of active cabling revolve around the greater complexity of designing and manufacturing them, owing to their ICs and the fact that they tend to integrate a lot of shielding, which contributes to them costing five to 10 times as much as passive cables. But just as demand has pushed down the price of fibre cables in recent years, so the rise of connected and autonomous vehicles might well drive a boom in these and other forms of harnesses to come. Acknowledgements The author would like to thank Scott Unzen and Travis Neumann at Omnetics, Steven Lassen at Lemo, Jeff Lewison at Northwire, Giorgio Potenza at Harwin, Dax Ward at St Cross Electronics, and Moises Valle at Click Bond for their help in researching this article. Tired of generic job boards and speculative CVs? Why sift through irrelevant CVs when a laser focused recruitment portal can deliver quality over quantity? Contact teddy@uncrewedengineeringjobs.com for more information on our 1x, 5x, 10x & unlimited job packages.
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