[masraum]

Originally Posted by Zeke

Help me out here. I thought steer by wire was pretty common. I know Toyota has a model coming out with it in the front. Nissan has had it. But I thought all cars with stay-in-the-lane technology had electronic input. Then there's the rear steer thing.

What is different in a self driving car other than there is a steering wheel to grab onto? If the driver does not have a grip on the wheel, what is driving the car?

So what is being said is the real innovation here is the elimination of the steering shaft? That's it?

Yes, I understand that the only connection from driver input to steering components will be a wire controlling a motor. I just don't understand what the news story here is.

I think the difference is that in my wifes car, the steering is mechanical, there's a shaft that runs down to a rack and pinion with a gear on the end and if I turn the wheel, the gear turns which causes the rack to skew. Then I assume there is a servo or motor on that shaft that enables the car to turn the shaft to try to put her car back into the lane if the car starts to wander. So there's a hard shaft, and I can "override" what the computer thinks (if I change lanes without signalling, it'll try to stop me, but I can still change lanes). I assume if I could disconnect the motor and still drive the car around just fine.

In pure "steer-by-wire" setups, the shaft will be gone. In what I assume is an overly simplified version, the steering wheel is essentially a big wheel that's only connected to a big "steering wheel position sensor". Then there would be a rack and pinion where it normally is, but the only thing connected to it would be a motor that could skew the rack back and forth. The only connection between the wheel and the rack and pinion would be wires and the computer's brain. If the system fails (whether you're parked or going into a turn at 70mph) you're screwed and no amount of sawing at the wheel is going to make the front tires turn.

If the car fails, you're completely screwed. If you're working on the car, and you want to push it out of your garage into the driveway, there won't be any steering.

There won't be any push starting one of those if the battery is dead since there won't be any steering.