Drive

Steer the way you want to: New Infiniti introduces Direct Adaptive Steering

At one time, cars all had manual steering, and it took brute force to muscle them into a parking spot. Then came power steering, which used a hydraulic pump to lighten the effort, and then electric power steering, which replaced the pump with an electric motor.

Infiniti has now introduced its Direct Adaptive Steering, or DAS, a completely electronic system that uses “steer-by-wire” instead of an actual connection between the steering wheel and the front tires. The system debuts on the all-new Infiniti Q50 sports sedan.

“One of the primary advantages is the ability to change the character of the car,” says Tim Franklin, senior manager of product planning for Infiniti Canada. “We’re able to affect how heavy the wheel feels and how quickly it turns. If you’re on a long road trip you’ll want a relaxed drive, or a spirited drive on a back road.”

The system uses actuators on the steering wheel and on the steering rack, along with a central control unit. When the driver turns the wheel, the wheel actuator sends the information to the control unit. This unit, in turn, sends information to the actuator on the steering rack, telling it how far to turn the tires. Infiniti says that the steering response is much faster than with a conventional mechanical connection.

Through a central touchscreen, the driver can set the steering feel, ranging from sporty to comfort. The steering wheel actuator adjusts the steering weight — the amount of force it takes to move the wheel. More weight gives a sportier feel, while less weight makes for a relaxing drive.

The system also changes the steering ratio, which determines how far you have to turn the wheel. A “quick” ratio moves the tires farther when the wheel is turned a little, producing a sporty feel where the driver doesn’t have to spin the steering wheel as much to go around curves. A slower ratio is preferable for highway driving, since it takes less effort and concentration to keep the car centred in the lane.

Although there’s no mechanical link during normal driving, the Q50’s system has a fail-safe. If the car’s electrical power fails, a clutch on the steering column instantly connects the steering wheel to the rack so the driver remains in control.

“The Q50 is still a sports sedan at its core, and customers want a sporty feel, but they also take it on road trips,” Franklin says. “Instead of splitting (the feel) and making a compromise, DAS lets them tailor it to how they want to drive.”

Extras

  • Electronic steering systems can be used in safety systems, including guiding a vehicle back if the driver inadvertently crosses out of the lane.

  • The Q50’s system “tunes out” vibrations caused by rough pavement for a smoother driver.

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