Tesla steer by wire

[rfuerst911sc]

This article states Tesla and Lexus are coming out with " steer by wire " . I will go on record now saying this is a bad idea . Trying to solve a problem that doesn't exist ?

https://www.yahoo.com/autos/tesla-patent-could-completely-revolutionize-050000854.html

[pavulon]

If you were disabled, it could be exactly what you need.

[RNajarian]

As some of the posts in the comment section stated they have been using “Fly By Wire” for 40 years now. Aircraft without this feature are primitive by today’s standards. However, trying to recover an aircraft in a spin or stall as it approaches 400 mph is much different than a leisurely drive around the block. The compressive forces on the surface areas are too great to overcome, hence the need for the fly by wire technology.

I’ve had power steering pumps go out on me but I still had control of the car.

I’m not too comfortable with the notion if my drive by wire fails that I have lost control of my car.

[Chocaholic]

Originally Posted by pavulon

If you were disabled, it could be exactly what you need.

Exactly. Car could be steered with a joystick for example.

[unclebilly]

But think how easy an LS swap could be… no more steering linkage getting in the way of the headers…

[unclebilly]

Originally Posted by Chocaholic

Exactly. Car could be steered with a joystick for example.

Or remotely by big brother…

[Dixie]

Next thing you know they'll replace brake rods with hydraulic lines. Imagine springing a leak!

[Tobra]

A vanishingly small number of automotive applications where this is an advantage, probably less than the number of privately owned wheel chair accessible vans.

[RNajarian]

Originally Posted by Capt. Carrera

Next thing you know they'll replace brake rods with hydraulic lines. Imagine springing a leak!

Yes but there is a redundant system to stop the vehicle which is independent from the hydraulics.

What would the redundant system in such a drive by wire be?

[Tobra]

That, and the hydraulic braking system is superior to mechanical in many ways.

The same cannot be said for steer by wire

[rfuerst911sc]

Good discussion . I come from a DOD career with the last 8 years building military aircraft . So I am used to multiple redundancy layers . My fear with steer by wire is will there be ANY redundancy?

Nothing is absolute except death and taxes but mechanical automotive steering has proven to be very robust . And not failure prone . Electronics on the other hand can fail from moisture or rodents as examples .

Comments above stating handicapped folks could be helped by steer by wire are good points . But I have to think a very small overall number . But still a valid point .

[masraum]

Originally Posted by rfuerst911sc

Good discussion . I come from a DOD career with the last 8 years building military aircraft . So I am used to multiple redundancy layers . My fear with steer by wire is will there be ANY redundancy?

Nothing is absolute except death and taxes but mechanical automotive steering has proven to be very robust . And not failure prone . Electronics on the other hand can fail from moisture or rodents as examples .

Comments above stating handicapped folks could be helped by steer by wire are good points . But I have to think a very small overall number . But still a valid point .

Exactly, planes have been fly-by-wire for a long time, but planes are expensive and have multiple layers of redundancy.

I feel like most cars these days are built to a price and then everything non-essential stripped out.

For steer or brake by wire (in many ways, far more important than throttle) you'd need multiple motors, systems, servos, pumps, etc.... to ensure that the likelihood of a failure is practically nil. And on top of that, most planes MUST be maintained to a MUCH higher level than most cars.

I feel (no evidence or expertise to back it up) that truly safe, robutst steer or brake by wire in a car would be an expenisive proposition.

[wdfifteen]

Originally Posted by Capt. Carrera

Next thing you know they'll replace brake rods with hydraulic lines. Imagine springing a leak!

LOL! And it only took them 40 years to decide it was a good idea to add a redundant system.
I'll bet there is some sort of fail safe or redundancy built in to the steer by wire system.

[flatbutt]

One question...why?

[Alan A]

Originally Posted by unclebilly

But think how easy an LS swap could be… no more steering linkage getting in the way of the headers…

Or you use this

https://www.speedwaymotors.com/Steer-Clear-Steering-Box-Drop-Brushed-Finish,6254.html?sku=8451000-16&utm_medium=CSEGoogle&utm_source=CSE&utm_campaign=CSEGOOGLE&gad_source=1&gclid=Cj0KCQjwhfipBhCqARIsAH9msbktyoSm86-Pizgty_7Nrk_fQNl5ZhTa3gIoIgrGS7KT2UfQH1wmu7caAm2pE ALw_wcB

Wish it was around when mine was built.

[GH85Carrera]

Originally Posted by Capt. Carrera

Next thing you know they'll replace brake rods with hydraulic lines. Imagine springing a leak!

Henry Ford was often quoted as saying "The safety of steel from pedal to wheel" as he was a big proponent of the Ford mechanical braking systems that used a steel rod to actuate the brakes.

Many of the new Porsches have rear wheel steering that is all electrical or computer controlled. And I suspect many cars in the near future will have electronic steering as it will make the car's design easier with no shaft from the wheel to a steering box. And no more steering columns shoved into the chest of the driver. That was mostly fixed with collapsible steering columns, but they can only collapse so much.

[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.

[masraum]

Originally Posted by GH85Carrera

Many of the new Porsches have rear wheel steering that is all electrical or computer controlled.

Lots of cars have had 4ws over the years, many of them being dependent on the speed of the car, ie, low speed turns (like u-turns or in a parking lot) had the rear tires turn opposite the front tires. High speed the rears and fronts turned the same direction to help with things like fast lane changes. I've got to assume that most of them were not purely mechanical like other cars.

https://www.hagerty.com/media/maintenance-and-tech/four-wheel-steering-is-having-its-moment-again/
"Many four-wheel steering systems faded from popularity by the early 2000s, but the technology has made a comeback with modern machines such as the Porsche 911, Lexus LC 500, Mercedes-AMG GT R and GT C, Lamborghini Aventador, Ferrari 812 Superfast, Ferrari GTC4Lusso, and others. Some version of four-wheel steering is even offered on mid- and full-size sedans from Acura, Audi, BMW, and Lexus. Not only has the technology evolved, but at the price point these (mostly) high-end cars inhabit, the cost and complexity of four-wheel steering is more palatable."

Some Nissan 300ZX Twin Turbos in the '90-96 range had 4ws (4 years after they put it in the Skyline GTR).

https://www.hemmings.com/stories/article/1988-91-honda-prelude-si-4ws
"The first automaker to sell a four-wheel-steer car in the U.S. was Honda: the 1988 Prelude Si 4WS...
The "Steer-Angle Dependent 4-Wheel Steering System" was conceived as an active safety feature to enhance emergency handling, as well as low-speed maneuverability, steering the rear wheels in the opposite, or same, direction as the front wheels, depending on the angle to which the fronts were turned. Its fully mechanical design differed from the hydraulic-mechanical and electric-hydraulic systems used by Nissan, as well as by Mazda on the 1988 626 Turbo 4WS that followed the Prelude Si 4WS to our market. And the benefit to Honda's sharp-looking, 2.0-liter DOHC 135-hp two-door was a turning circle cut from 34.8 to 31.5 feet, plus enhanced maneuverability and stability."

[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.

[aigel]

The handicapped argument is moot, most cars that have steering assist or self-driving features such as the Tesla already could be driven with a joystick or similar if programmed accordingly.

I am not too worried about this. This can be made reliable. This is a good article showing the reasoning and implementation. In a couple decades self driving cars will be the norm, so then nobody will care what steers it anyway.

https://www.roadandtrack.com/news/a43350167/toyota-steer-by-wire/#:~:text=Toyota%20is%20not%20the%20first,the%20whe els%2C%20just%20some%20wiring.