• We recently featured Mercedes' "electronic drawbar" system, which allows
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one truck to follow closely behind another on the motorway (CM 10-16 June). The system relies on electronically controlled steering, which is likely to make an appearance in production trucks before long. At Papenburg we tried an Actros tractive unit with electronic steering—the steering wheel is conventional, but there is no steering column.
The system had been set up to be very direct, and it took some getting used to: there's no play around the straight-ahead position, and tiny corrections result in twitching motions on the road. But after a few minutes we were confident enough to perform a 50km/h "elk test"—a rapid lane change and back again, between cones—without drama.
The system is fail-safe, in that it operates even with the engine oft; and promises more flexible cab layouts and more predictable steering behaviour, with different levels of steering effort to suit different conditions.
But Mercedes has taken the "drive-by-wire" idea a stage further; it has put together an Actros with no steering wheel or column... and no pedals. But press a button, and carbon-fibre armrests whirr into position, each fitted with a joystick. These "sidesticks" pivot from side to side for steering control and sense fore-and-aft pressure to control the throttle (which drives through a fully automatic Telligent gearbox) and the brakes.
A trigger on each stick controls the indicators; thumb switches allow manual gear shifting. The driving position is comfortable, and one soon gets used to the small movements required for steering. Of course, it's also possible to drive with either hand.
Sidestick control looks futuristic, but this vehicle simply combines a variety of current components. It might also catch the eye of safety legislators, because the design reduces the number of intrusive controls in front of the driver.