Automated technology is out-pacing acceptance, but the stepping stones toward adoption have been laid in the form of adaptive cruise control and collision mitigation safety systems. Steering is the next logical step in its evolution, and availability of driver-assist steering functions is closer than you may think.
ZF, a supplier of driveline, chassis and safety technology, recently put me behind the wheel of ReAX, its hydraulic electric steering system, in which an electronic motor provides the required assist to the hydraulic steering system. Sensors gather torque, steering wheel position and vehicle speed data to ensure this assist matches the driving conditions. In practice, ReAX provides a steering assist experience that reduces the torque required to turn the wheel in slow-speed, figure-eight maneuvers, for example—much to the relief of my over-worked arms—and can also assist in increasing the torque required at higher speeds to hold the truck steady, aiding fleets safety efforts.
According to Mark Cartwright, global product planning manager at ZF, the movement toward automation has spurred the advancement of this technology, but the question today is: What can this technology do for me now?
“ReAX is the expansion of both the technologies toward autonomous behavior on vehicles and the improvement within our technology itself,” he said, as a pair of ReAX retrofitted trucks, one on-highway and the other vocational, were put through their paces on a closed course behind him. “We’re upgrading to next-generation hardware and software, as well as the implementation of the cameras and radar systems. ReAX is all about advanced driver assist systems [ADAS]. That means helping the driver be better today, which is what we all want, no matter what the future holds.”
In addition to the operational benefits, Cartwright explained that the ReAX steering system will integrate into other components, like ZF’s e-ActiveMode hydraulic steering pump, and engine-off coasting systems to provide noticeable fuel efficiency gains. Cartwright estimated up to 1.7% annual fuel savings, or approximately $1,250 per year, given a typical long-haul application putting on 120,000 miles with those three aforementioned systems working together. While the engine-off coasting contributes most of that savings, the ReAX and e-ActivMode system together can save $200 per year in fuel and enable power steering during engine off operation.
Continuing down the road toward automated trucks, Cartwright outlined three levels of steering assist systems that will require adoption before hands-off autonomy is a reality. The first is likely already in some of your trucks today—lane departure warnings. Beyond that, Lane Keep Assist provides torque to the steering wheel that urges the truck away from lane boundary markings. The next evolutionary step will be Lane Centering Control, in which the torque on the wheel urges the truck toward the center of the lane. From there, steering assist systems would urge the vehicle toward the optimal lane trajectory throughout its route. This would be more akin to the futuristic automated operation that comes to mind when talking about autonomous trucks.
ZF is currently shopping ReAX around to truck OEMs with the goal of getting the option available at the factory within the next couple of years. The company is also looking into developing an aftermarket add-on.