Cybertruck Steer By Wire Safety Concerns and Details

[Dan D.]

Steering failure in a customer vehicle this year. What’s the over/under?
Very unlikely the failure will be due to lack of redundancy IMO. It will be a software bug if it happens.
I am curious how the power redundancy works. Are there two 48V batteries? Or maybe the HV battery and 48V can power the steering rack independently?

With some CT owners now having apparent software issues with their steer-by-wire I wonder why you'd take "software bug" out of "lack of redundancy"? Shouldn't redundancy take software bugs into account? ie: what's the critical path to saving the truck if there is a software bug, surely there's another level of redundancy that needs to be added?

Because if the drivers didn't stop for the critical warning, would they in fact have experienced steering failure? Some conditions are very unsafe to stop - eg: on a highway bridge with no shoulders in the rain and dark. We are advised in BC to get off the bridge first, you will 80%+ be creamed if you stop for any reason on the highway bridge.

 

[Daniel in SD]

With some CT owners now having apparent software issues with their steer-by-wire I wonder why you'd take "software bug" out of "lack of redundancy"? Shouldn't redundancy take software bugs into account? ie: what's the critical path to saving the truck if there is a software bug, surely there's another level of redundancy that needs to be added?

Because if the drivers didn't stop for the critical warning, would they in fact have experienced steering failure? Some conditions are very unsafe to stop - eg: on a highway bridge with no shoulders in the rain and dark. We are advised in BC to get off the bridge first, you will 80%+ be creamed if you stop for any reason on the highway bridge.

My assumption is that the errors people are seeing are false positives. Now someone needs to go into the code and fix it which of course introduces the possibility of breaking it. There are redundant controllers but they're probably running the same software so that redundancy wouldn't help.

I'm sure the vehicle will allow you enough speed to get off the bridge. After you restart it will be limited to very low speed. The chances of have two failures in close succession is very low.

 

[Dan D.]

My assumption is that the errors people are seeing are false positives. Now someone needs to go into the code and fix it which of course introduces the possibility of breaking it. There are redundant controllers but they're probably running the same software so that redundancy wouldn't help.

I'm sure the vehicle will allow you enough speed to get off the bridge. After you restart it will be limited to very low speed. The chances of have two failures in close succession is very low.

Assuming they could restart/reboot the truck I might expect the exact same failure to occur, it's probably still occurring and a reboot won't make any difference. Critical failure implies stop immediately or suffer the consequences - but it doesn't seem to totally require an instant stop. However if someone keeps driving for some minutes "to get somewhere safe" and the steering fails completely then any damages might fall under "driver error" for failing to stop.

But, time will tell if steer-by-wire as implemented by Cybertruck is 100% reliable with adequate redundancy to enable a safe warning and emergency stop. How much warning should a driver get before total steering failure? Does the truck make sufficient warning, or can everyone assume you can slowly drive in "limp mode" or something. If total steering failure is imminent, is "critical failure" sufficient as a warning. Maybe it should flash and alarm DANGER - STOP IMMEDIATELY so you know you don't have ANY time to limp anywhere. I really hope that if there are any total steering failures that Tesla won't hide behind "we warned you with a system message, but you didn't stop quickly enough".

 

[Nack]

Given their lack of safety concerns with the L2 ADAS system I assume the “driver must be ready to jump in and take control at a moments notice.”

Kind of kidding but would also not be surprised at all thats their plan.

 

[Daniel in SD]

Assuming they could restart/reboot the truck I might expect the exact same failure to occur, it's probably still occurring and a reboot won't make any difference. Critical failure implies stop immediately or suffer the consequences - but it doesn't seem to totally require an instant stop. However if someone keeps driving for some minutes "to get somewhere safe" and the steering fails completely then any damages might fall under "driver error" for failing to stop.

But, time will tell if steer-by-wire as implemented by Cybertruck is 100% reliable with adequate redundancy to enable a safe warning and emergency stop. How much warning should a driver get before total steering failure? Does the truck make sufficient warning, or can everyone assume you can slowly drive in "limp mode" or something. If total steering failure is imminent, is "critical failure" sufficient as a warning. Maybe it should flash and alarm DANGER - STOP IMMEDIATELY so you know you don't have ANY time to limp anywhere. I really hope that if there are any total steering failures that Tesla won't hide behind "we warned you with a system message, but you didn't stop quickly enough".

I've driven 70k miles without a steering motor failure so I would not be worried about a steering motor failing during the time it takes to pull over to a safe spot. Hopefully the steer by wire system has the failure rate of two independent electric power steering systems failing in quick succession (extraordinarily unlikely). This is why I think adequate redundancy is not the issue, it's the software to detect and respond to failures that's the riskiest part.

 

[Nack]

Yeah the software is a very significant risk. How it handles errors and edge situations is where people should be concerned. The hardware is really nothing groundbreaking.

 

[outdoors]

So I know not many of you have one, but I love the steer by wire. I can turn this truck at low speed or even more at high speed quickly in a way that I just can't do in my suburban. Will be very interested to see how it does in the moose test. The short turn makes it easy. I get plenty of feedback, but a none issue, and would invite many to try it before casting stones.

Also pretty cool in service mode you can see all the coms going back and forth on all the systems. See who is talking, and who is having problems. Bugs in the system, but don't see them on the steering side.

Maybe some old folks may not get the backing up, but I got it in the first 5 or six back ups to a SC.