Digital 'fly by wire' steering

[YoungStranger]

do you think Model 3 will have 'fly by wire' steering rather than a mechanical linkage?. The interior shots on the initial launch with no dash hint at such an approach.
Advantages would be:
Simpler, cheaper Left hand/ right hand production
Sophisticated and programmable feel to suit different drivers and situations
Better body shell integrity
Better integration with autonomous driving systems
Better safety in case of impact for driver (although modern design and airbags probably already mitigate this).

I heard a comment somewhere that legislation might require a mechanical linkage, but surely a digital approach might be even more reliable and safe.

Do you think this is likely on model 3?

 

[Johan]

Yes very likely.

 

[theboom1]

do you think Model 3 will have 'fly by wire' steering rather than a mechanical linkage?. The interior shots on the initial launch with no dash hint at such an approach.
Advantages would be:
Simpler, cheaper Left hand/ right hand production
Sophisticated and programmable feel to suit different drivers and situations
Better body shell integrity
Better integration with autonomous driving systems
Better safety in case of impact for driver (although modern design and airbags probably already mitigate this).

I heard a comment somewhere that legislation might require a mechanical linkage, but surely a digital approach might be even more reliable and safe.

Do you think this is likely on model 3?

While I can agree with most of what you said, the reliability is a no. Electronics are more reliable than a simple direct mechanical linkage? No.

 

[strykeroz]

While I can agree with most of what you said, the reliability is a no. Electronics are more reliable than a simple direct mechanical linkage? No.

I'd like to see the data behind your assertion.

 

[JeffK]

While I can agree with most of what you said, the reliability is a no. Electronics are more reliable than a simple direct mechanical linkage? No.

I'd like to see the data behind your assertion.

Some good points:

2016: Infinity recalls Q50 due to software issues in the electronics
Infiniti Q50s recalled for steering software issues
2014-'16 Infiniti Q50 Recalled for Steering Problem | Edmunds.com

2014: Infinity recalls Q50 due to temp related electronics failure
2014 Infiniti Q50's novel drive-by-wire steering system recalled

According to the National Highway Traffic Safety Administration, on a small number of examples, the Q50's optional by-wire system may fail if the temperature in the engine compartment drops below freezing. There's a backup mechanical setup in place should the electronic system fail, but NHTSA says that the backup system may also fail to engage in time to avoid a crash.

2010: Toyotas are killing people:
http://wheels.blogs.nytimes.com/201...-sensor-is-part-of-drive-by-wire-system/?_r=0

In a filing with the National Highway Traffic Safety Administration, Toyota said the latest problem was in the pedal sensors of affected vehicles. When the heater is turned on in a car that is cold, internal water condensation on the cold parts can cause a sliding component inside the gas pedal assembly to stick instead of move smoothly. The defect may cause the throttle to stick in an open position or to move stiffly during opening and closing, requiring more pedal pressure.

The pedal sensor is part of a so-called drive-by-wire throttle system, in which the gas pedal has no direct connection to the engine through a cable or mechanical linkage. A sticking pedal in an older car with a cable or mechanical link would typically be solved with a squirt of oil or dab of grease, a straightforward task for a handy car owner.

etc, etc.

 

[strykeroz]

My counter point to that is every other vehicle on the road that uses a throttle position sensor rather than a physical cable that hasn't made the news. But, no number of anecdotes are equivalent to data. My instincts are telling me the opposite of your assertion. But instincts, like anecdotes, are equally not data.

I am actually genuinely interested in seeing some data on the reliability comparison.

 

[Johan]

My counter point to that is every other vehicle on the road that uses a throttle position sensor rather than a physical cable that hasn't made the news. But, no number of anecdotes are equivalent to data. My instincts are telling me the opposite of your assertion. But instincts, like anecdotes, are equally not data.

I am actually genuinely interested in seeing some data on the reliability comparison.

I'm quite sure the NHTSA for example has this data and if it had shown the new technology (drive by wire) as being less safe or more prone to error than direct mechanical linkage between the steering wheel and the wheels then I'm sure we would have heard something by now...

 

[YoungStranger]

I am pretty sure that a digital system would be pretty safe... they would follow airline practice and build in redundancy... you don't worry about Airbus es and boeings crashing without mechanical linkages, and you cannot slow down and park them!

 

[strykeroz]

I am pretty sure that a digital system would be pretty safe... they would follow airline practice and build in redundancy... you don't worry about Airbus es and boeings crashing without mechanical linkages, and you cannot slow down and park them!

Yes however different standards apply. They build in quadruple redundancy. In the case of GM (at least, where I'm familiar) there's just the single channel for the TPS.

Having said that, there is also only a single channel in the mechanical linkage of old, and I've been in a car (a Ford) where the throttle cable jammed and the car caught fire when we turned it off, and another (a Holden, Australian for GM) where the steering box failed leaving us with a car (thankfully at low speed in reverse) where you could spin the steering wheel infinitely in any direction but actual control. Again, with my caveat that no volume of anecdotes are ever to be considered data. I just wish to point out that mechanical fails too, so I'm expecting like the OP that the fly-by-wire alternatives must be at least as reliable, if not more so.

 

[eSpiritIV]

Doesnt the Toyota Prius have fly by wire steering? There are zillions of those on the road.

 

[JeffK]

Doesnt the Toyota Prius have fly by wire steering? There are zillions of those on the road.

those are mechanical as far as I know...

 

[Skotty]

No. What would you gain from that? Motorized steering already works really well with a mechanical linkage. In my opinion, steering and brakes should always keep their mechanical linkages; they serve as a reliable backup in the case of electrical failure.

Here's a reliability test for you. Take a mechanical and drive-by-wire system. Hit both with a hammer. See which one works better afterwards. The great thing about mechanical systems is that they are a lot like biological systems. Most of the time, it can take some damage and keep operating (think auto accidents). However, with electrical/computerized systems, you lose one transistor and the system dies completely. You can try to build in redundant electronics, and that can help, but isn't that itself just an admission that they are not as reliable?

 

[diamond.g]

No. What would you gain from that? Motorized steering already works really well with a mechanical linkage. In my opinion, steering and brakes should always keep their mechanical linkages; they serve as a reliable backup in the case of electrical failure.

Here's a reliability test for you. Take a mechanical and drive-by-wire system. Hit both with a hammer. See which one works better afterwards. The great thing about mechanical systems is that they are a lot like biological systems. Most of the time, it can take some damage and keep operating (think auto accidents). However, with electrical/computerized systems, you lose one transistor and the system dies completely. You can try to build in redundant electronics, and that can help, but isn't that itself just an admission that they are not as reliable?

Really just faster release in RHD markets because you don't have to worry about where to fit all that mechanical stuff in the dash.

EDIT: It is the reason the US never saw any of the Original Skyline GT-R's. Nissan couldn't be bothered to move the Turbos (I believe it was them) so the steering column could go on the other side. <well that and likely couldn't pass emissions, but I digress>

 

[YoungStranger]

No. What would you gain from that? Motorized steering already works really well with a mechanical linkage. In my opinion, steering and brakes should always keep their mechanical linkages; they serve as a reliable backup in the case of electrical failure.

Here's a reliability test for you. Take a mechanical and drive-by-wire system. Hit both with a hammer. See which one works better afterwards. The great thing about mechanical systems is that they are a lot like biological systems. Most of the time, it can take some damage and keep operating (think auto accidents). However, with electrical/computerized systems, you lose one transistor and the system dies completely. You can try to build in redundant electronics, and that can help, but isn't that itself just an admission that they are not as reliable?

To be fair to myself.. "even more reliable" was just a figure of speech to emphasise the probable reliability of an electronic system and not a quantitative assertion that it is more reliable than a mechanical rig (although as a previous poster noted, mechanical failure can happen). Not sure why I would take a hammer to either system though!

An importantl advantage also for Tesla might be ease of assembly, which might save a few dollars per car. A digital system would only need a couple of bolts and a wire to plug in. On the other hand, axle assembly with multiple electric motors (or hydraulics) would be more complex, but again might only require a wire.

Digital steering control would also facilitate four wheel steering, with similar assemblies used for rear axles.

PS. See where you are going with auto accident thought, but most front end collisions will knock out the steering anyway. You could picture some scenarios where digital systems could still function, where mechanical ones would not. Either way I would prefer to be on a tow truck though!