Nissan's next-generation steering employs a steering angle sensor at the steering wheel, three ECUs for control, electric motors to power the rack, and a steering force actuator near the driver to retain the vehicle's "steering feel."
Add me to the "no" list. I know the system could perform wonderfully, but it could also fail spectacularly. The hydraulic assisted system in use today still operates, albeit with great effort, in the event of a complete hydraulic failure, and steer by wire would not be capable of that.
On most posts this bulletin board leans towards technology at the expense of increased risk. Autonomous vehicles don't frighten most Design News readers, so I'm a little surprised, and encouraged by the negative response to steering by wire.
I have had nothing but bad experiences with computer control of everything from turn signals, headlights, antilock brakes and smog control systems in my Chryslers. Why anyone in their right mind would want to drive a car "by wire" is beyond me. It is just a bunch of "Microsoft moments" (blue screen of death) waiting to happen at the worst possible time. I prefer my vehicles have the least amount of "points of failure" as possible.
The basic function of a vehicle is stop/go/turn. That's it! Everything else is bells and whistles. At 60 mph, two things I don't want failing; stop and turn. Survivability goes way down if those systems fail. 'Go' is a snug third. I had a Ford Escort and going through an intersection; there were dips on each side of the intersection as you crossed the intersecting road. The engine stopped running after going through the second dip. I was able to steer to the side of the road and stop; parking legally. The problem was traced to a pin in a connector; the pin broke off at the wire crimp. The whole incident was minor. But if the steering or brakes had been lost things could have been much worse. The car I have now is 'go'-by-wire. The jury is still out on that one but it appears to be hung at the moment.
The steer-by-wire might have a niche market such as applications where a steering wheel is difficult or impractical (example, handicap). When I read these announcements, I pause and give thought what they are saying. Example: Nissan states that '... the advantages are ...'. But they never mention the disadvantages. There are always disadvantages. Red flags: '... the clutch is disengaged 999,999 time out of a million.' If a system is disengaged for that long, what guaranties that it will work when needed? How will you know if the backup has failed? Is it ever tested?
The car is not an airplace and its maintanance does not fall under rigorous training and scrutiny.
First we hear of throttle by wire systems that won't allow heel and toe downshifts and now steering systems that isolate direct steering effort feedback and recreate a subset of the available feel. Its clear during my commute that there are many people that are absolutely ready for the driverless car (cell phone in one hand, cigarrette in the other, what's on the steering wheel?) but for those of who find joy in driving there are dark times coming.
So let me get this straight, we introduce steer by wire so we can remove the feel of rough roads etc. but we dial in the feel electronically because that wouldn't be good for the driver, and were saving weight even though we added 3 ECU's AND a clutch to re-engage the traditional steering column if all 3 ECU's die (which will happen every time an alternator dies)
I think some engineers in the automotive industry have lost the plot, They're putting complexity in for the sake of it.
I don't get it. All I see is a riduculously complex and expensive system which the owner has to pay for but adds little or nothing useful to the operation of the vehicle.
In my view, you had redundancy and tactile feedback with a rod that connects to the gear that moves the wheels. How much more elegant, cost effective and reliable can you get than that? Seems the weight issue is a materials question, not motors and redundant computers.
That is 100% correct. In the aerospace industry there is a massive effort to test and qualify all fly by wire systems to prove that they are fully redundent and fail safe. To incorporate this into a car without a mechanical backup will cause a very complex and expesive system. This is why the aircraft that are relatively inexpesive (single engine puddle jumpers) are still cable and pulley. We may see a day when drive by wire is 100% but I beleive it will be in the high end cars where cost is less of an issue.
I'm going to play teh antagonist here. When it comes to driving, feeling the road is much more important to me than a smooth ride. The feel actually helps me know that a tire has a problem before it is a real problem. I get the whole technology thing for the future, but nothing can replace a solid mechanical system. Removing that is like putting a rocket on the road with no breaks. There always seems to be delay in control system response, and that nanosecond of steering response has saved my life. I embrace technology, but I'm not confident that this is the right way to go.
Anyone remember the accelerating Toyotas? I know GM has been working on this for over 20 years. I think it will ultimately come down to consumers and federal mandates (such as CAFE).
The new 787 Dreamliner is entirely electronic. The difference is the rundundant back-ups are not going to exist in the physical sense on cars (weight, weight, weight). So the development in the automobile has to be sensor/control failsafe that stops the vehicle. It is better to get out of the car that is on the side of the road than trying to parachute out of an airplane with type of failsafe!
Tesla Motors’ $35,000, 200-mile electric car may not revolutionize the auto industry by itself, but it could serve as a starting point for a long, steady climb to a day when half of the world’s vehicles will be plug-ins.
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