 | Quote: Driving Nissan’s New Steer-By-Wire System
Jason Torchinsky
The whole point of Nissan dragging my pale, pale ass halfway across the world was so they could show off a bunch of new tech they're developing. And show off they did, with prototypes and inflatable cars and cutaway engines and all sorts of good stuff like that.
I'll be reporting back to you everything I saw, the good and the bad. But let's start with something pretty good— the steer by wire system Nissan's marketing machines have dubbed Next Generation Steering.
I know when most of us think about steering-by— or hell, almost anything by-wire, we get visions of video game controllers and cold, numb feedback, like trying to make sweet, sweet love to that sex-robot that tries to sell me vodka from the future on TV. And that's how I came into this as well. I've driven cars with purely mechanical, unpowered steering, hydraulically-assisted steering, and electrically-assisted power steering. Generally, I've never really been that fond of the electrically-assisted variety, and I assumed that the steering by wire system would be worse.
That's what I get for assuming. See, when you assume, you pay a sum to me or something like that, I'm told. And I'm not so proud that I can't admit I'm wrong. Because I was very wrong.
I was provided with two Infiniti G37s to drive, back-to-back. One had the conventional hydraulic steering, and the other incorporated Nissan's new all-electronic system. I drove both cars on Nissan's GRANVIEW test track, which includes areas of varying and rough road surfaces.
Before I get into my impressions, let me describe what Nissan calls their "Next Generation" steering system. It's still a conventional rack-and-pinion assembly, but instead of the wheels being turned based on direct (and assisted) input from the steering column to the pinion, the rack is moved (and hence the wheels turned) by action from two mounted motors, one by each wheel. One motor could be used, in theory, but for size reasons (and possible later independent wheel steering control) Nissan decided on two.
So, electronic signals from the wheels' position are sent to the motors, which then turn the wheels. If we stop here, it may as well be a Pong paddle. Luckily, Nissan has a third motor, mounted at the steering wheel assembly, to transfer feel and resistance to the driver. This part makes a huge difference.
What this setup means is that steering feel can now be selective. Instead of feeling every bump and jar of the road through the wheel or dampening it away, the types of feedback from the road can be dynamically programmed into the system, letting the driver feel the general feel, cant, and surface of the road without jarring or vibrating. It means that steering ratios can vary based on speed, driver input, road/slip conditions, or more.
So, when I drove the normal G35, I found the steering not bad; a touch over-dampened, but it is a luxury car, after all, and there was the normal amount of play one expects from any steering system. It was reasonably responsive, but nothing amazing.
The all-electronic system, however, was noticeable right from the start. Turning the wheel resulted in extremely direct and immediate motion of the front wheels— it felt almost like the 1:1 ratio of a go-cart. Turn the wheel a fraction, and you feel the car steer just that much. No slop, no over-assisted feeling, just really direct steering. As speed increased, the brain of the system added a bit more play and a modified steering ratio, since at highway speeds you won't want the very quick and direct steering of lower speeds.
I could still feel the road, thanks to the three independent computers processing gobs of data and returning more or less wheel resistance and even some subtle, road-mimicking vibration. Considering my expectations going in, it was very impressive.
In fact, it made me think that the often-boring electronic (usually column-mounted) assisted steering will become a stop-gap measure until a truly new system like this comes to market. Nissan says it'll be ready next year and I'm certain almost everyone else is working on something similar.
Also interesting from layout and styling perspectives is that, technically, no steering column is needed. The systems I was shown and drove to have a clutch-actuated steering column as an emergency backup (or if you're pushing or towing a dead-battery car or something like that), but it's easy to picture that precaution going away down the road. That will open up all manner of placement options for the driver, or even allow multiple, dynamically switchable driver locations. Localizing for left or right-hand-drive will be trivial, as well.
Nissan's system will also work in conjunction with other driver aid technologies (visual lane recognition, etc) and, if it perceives the goal is to drive straight in a highway lane, make small adjustments to keep the vehicle steady and straight, even if driver input is sloppy, erratic, or affected by a poor road surface. I wouldn't want this to edge too much into autonomous territory, but Nissan assured me the adjustments are minor and only when it's very clear straight, simple driving is desired.
Despite my prejudices, I was very taken with the new steering system, and that genuinely surprised me. If this was an afterschool special, I'd have a focus and a monologue where I realized that while I learned something, I still have a lot of growing up to do. But if growing up means a world where cars can have steering that feels like this, I'm all for it.
(Full Disclosure: As previously mentioned, Nissan wanted me to play with this stuff so badly they flew me to Japan, put me up in a hotel, and allowed me to play with some of their cool, JDM cars.) | |
