The XOS 2 is nearly usable for the latter job, but even at 50 percent more efficient than the original (by the company's last count) it's still a prototype that requires a tethered high-pressure hydraulic engine to function.

ENGADGET: Raytheon's Sarcos XOS 2 military exoskeleton just does the heavy lifting -- for now

It is powered by an engine which drives a hydraulic pump to send oil under high pressure around its plumbing in order to animate its limbs.

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Controlling steering using electric motors also helps to reduce fuel consumption and hence carbon-dioxide emissions. (Electric motors require power only when the steering wheel is turned, whereas a hydraulic pump drains power from the engine all the time.) Ford reckons 90% of its cars will have electronic steering within three years.

ECONOMIST: Rational consumer

An engine running constantly in the hold powered hydraulic and electrical systems that in theory allowed a crew of 4 to do the work of 10 or 20.

FORBES: Global Life