2 suppliers steer in opposite directions

TOKYO -- Two of the world's biggest steering suppliers have diametrically opposed views of the importance of steer-by-wire to the future of autonomous driving.

The disagreement pits Toyota-affiliated JTEKT Corp., the world's top steering supplier, against NSK Corp., the world's No. 3 electric power-steering player, in visions for the future.

JTEKT says a shift toward steer-by-wire is inevitable and necessary for tomorrow's self-driving cars. NSK says it is too costly and today's electric steering systems will suffice.

The Japanese rivals' divergent strategies underscore the debate about how fast a "by-wire" age will arrive in which steering is no longer a physical extension of a driver's firm grip.

Steer-by-wire systems convert steering wheel movements into electronic signals that control electric motors moving the wheels. Proponents see it as a natural progression of the brake-by-wire and throttle-by-wire systems already in use.

Eliminating the bulky steering column can reduce costs, open new room for design flexibility and improve steering precision.

But adoption has been slow amid misgivings over entrusting such critical operations to computers. Meanwhile, rigging redundancies to allay safety concerns boosts complexity and costs, at least while the technology is still in its infancy.

Nevertheless, JTEKT President Tetsuo Agata is bullish on the technology, calling it "essential" to future automotive design. JTEKT already is developing the technology, he said in July. "We are working with steer-by-wire because it is necessary and almost mandatory to achieve autono-mous driving systems," he told Automotive News. "We are working now to develop such a system."

On the other side is NSK, where executives have no interest in steer-by-wire systems and are pursuing alternative systems based on today's electric power-steering technology.

Both companies have a say in future trends because of their size. JTEKT, which is 22.5 percent owned by Toyota Motor Corp., is not only the top electric power-steering supplier but the biggest steering supplier, period, according to IHS Automotive. NSK ranks No. 3 globally in electric power steering and No. 5 when all steering systems are tallied, including hydraulic ones.

Drive-by-wire systems are deployed in such vehicles as the Infiniti Q50 sedan and are being explored by other carmakers. The Infiniti system is made in-house by parent Nissan Motor Co.

Ahead of the 2013 Tokyo Motor Show, Honda Motor Co. showed reporters its own prototype steer-by-wire system, then in tests.

In the Infiniti system, three electronic control units backstop one another to constantly monitor for malfunctions. And if anything still goes awry, another fail-safe feature re-establishes a backup mechanical connection.

To skeptics, that is ample proof of the system's limitations.

"Even if they install steer-by-wire, they still need the redundant mechanical system," NSK CEO Toshihiro Uchiyama said at a media roundtable. "Maybe safety requirements will have to be changed or the reliability of steer-by-wire systems will have to be enhanced dramatically."

The added costs don't warrant the shift when existing technology can achieve similar results, he said.

NSK engineers envision what they call "robotized" steering.

They use sensors and software-controlled steering-assist features that can be used in tandem with existing electric power-steering systems. Such features already are being developed to keep a car automatically centered on a crowned road or tone down oversteering without the driver even noticing.

NSK wants to migrate its electric power steering from the applications in column-mounted motors, which require less torque, to more powerful systems with motors down closer to the wheels. These pinion or rack steering systems are better suited to the bigger vehicles preferred in markets such as the U.S.

"We don't think steer-by-wire is a solution to autonomous driving," Uchiyama said. "Electrically assisted mechanical systems are more reliable and give better steering feeling."

Some analysts agree with NSK that, in the near term, added costs for safety redundancies are big hurdles to steer-by-wire.

In addition, removing the metal steering column is not necessary for autonomous driving, even in self-driving cars already being tested, said Eric Fedewa, leader of IHS' SupplierBusiness Team.

Midterm projections show autonomous driving remaining a niche market. IHS forecasts autonomous vehicle sales beginning in 2020 and reaching just 253,000 vehicles a year globally by around 2025.

But steer-by-wire backers say the technology will come to market hand-in-hand with automated-driving functions.

Part of the reason is the push toward lighter, more fuel-efficient cars. Dropping a mechanical back-up steering column may require a triple redundancy network of computer chips backing up one another as a fail-safe. But it will help shed crucial pounds.

It also will clear room for designers to add other onboard interconnectivity features unique to autonomous driving.

Finally, it also promises smoother driving by reducing road vibrations transmitted to the driver through the steering column.

JTEKT's Agata remains bullish against the naysayers.

"Jetliners are already steer-by-wire," he said. "The speed of adopting autonomous driving systems is accelerating. If we can eliminate the mechanical linkage, we can have more freedom in automotive design. In the future, steer-by-wire is essential."