Lane Tracking Assist Issue

Good work researching.

Could be. But there is very specific information in the repair manuals about the extra connection for a wheel sensor, so the most likely case is that the optional extra wheel sensor is being wrongly described, not that it doesn't exist.

If there can be a sensor in the wheel, there's no point it being a torque sensor, as they already have that in the steering column ECU. It could possibly be a pressure sensor rather than capacititative - that would be consistent with your latest results. (Note that by saying "force" you're conflating two things you'd want two different types of "force" sensor for - turning the wheel and holding it).

Or maybe it's even a combination of capacititative + pressure, so gloves would make it work less well, but it would still work somewhat?

But earlier you said you had to "wiggle it", suggesting it was relying on torque, with no wheel sensor. The latest results don't seem consistent with that - you weren't having to wiggle it - you just had to be touching it more than lightly.

The "have to wiggle it" matched the non-Prime owner complaints. This new report doesn't. They were saying that no amount of simple grip would appease it, unless they clearly provided some torque input. Whereas you're trying to rationalise your working touches as being detectable via torque alone.

 

I am pretty sure there is a capacitive sensor in the steering wheel like in any other car with ADAS.

Hands-off detection (HOD)—crucial for driver assistance and automated driving systems

 

@KMO: This is fun to be fiddling with and figuring out. When I've been talking about wiggling the wheel to calm the ADAS down, that has been just a quick and easy way to appease it, applying lots of pressure and torque ("shaddup and drive!" ). The experiments a few days ago were all about applying as subtle pressures and torques as possible to try and distinguish between the two.

Its pretty easy to apply torque or pressure without human touch. I think the cardboard box test was pretty conclusive in that respect. Torque definitely *is* an input. The question is if it is the only input?

Applying touch without pressure or torque is impossible in the absolute sense, any touch is going to apply some no matter how small. Hence that testing was less conclusive. I'm inclined to believe the amount of touch I had to apply to appease the ADAS was enough that it could have been detected by torque, but it's just that, an inclination.

If you can think of a different experiment to try that is more definitive, happy to give it a stab. No interest in tearing the steering wheel apart though . While I don't have them, can't you get gloves specifically designed to be "sensed" by captouch screens? Would strapping one of those to the wheel be considered a more definitive test? I'm open to ideas.

The scientific method is a good thing! I remember it as four steps: Hypothesize, test, observe, repeat. Google searches say it's seven steps though, so I guess I only remember the fun parts. Last step is communicate, so that is what PriusChat is for!

will

 

Indeed, but that's apparently a clear behaviour difference to the non-Prime complaints. Meaning 3 possibilities:

1. Different user perception - it's not a side-by-side comparison. The cars are actually behaving the same.
2. You don't have an extra touch sensor, but do have a much much more sensitive torque sensor than they do.
3. You do in fact have the extra touch sensor the manuals suggest your car should have.

I think 3 is the most likely possibility. I can't see any reason to think that the manuals are wrong. They suggest your car should have an extra sensor, and the tests - albeit by different users - appear to confirm that your car is behaving better than the cars that shouldn't have the extra sensor.

So Occam's razor suggests it does in fact have the expected extra sensor.

 

Is it any different than in Gen 4?

All EPS systems with or without hands-off detection/warning should have a torque sensor. Hands-off detection also requires a capacitive sensor, which varies the capacitance according to the pressure applied, as described at the link in my previous post.

The only difference in Gen 5 Prius Prime vs. Gen 5 Prius should be the infrared eye camera because of the TJA in the former.

Torque sensor for electric power-steering system

 

Given I was using instensively TSS 3.0 now for over a week, especially in a car WITH and one WITHOUT capacitive steering wheel sensors I can add my 5 cents as well (mostly LTA).

First regarding the capacitive sensory - they worked pretty good and sensitive (minimal touch was enough) so that it was generally a non issue. Car never really nagged unless I was really driving hands free. I just found out the difference when I switched to a lower trim car which apparently did not have capacitive sensors which was initially an annoying experience as I had to wiggle the steering wheel from time to time.

Later this became a minor issue as well as I used the LTA more in a collaborative fashion - meaning I always keep it on but usually do my own steering. I think the whole TSS3.0 excels in this regard - its not a you or the car... its more like you keep the upper hand and the car assists collaborativly in the background. After all perfectly fitting for a level 2 system compared to the approach Tesla tries to shoehorn into a level 2 system.
Eg. when changing lanes on the highway (no LCA), the system always helps me to keep centered perfectly (like on rails) and makes a smoth transition without fighting me or turning off.

Scenarios I tested where through smaller towns (~50kmh), country side roads (~100kmh) and quite some Autobahn (vmax 180kmh but usually ~150kmh). System works well until vmax, only slight issues I had was slight left/right bounce behaviour at night (~150kmh). I assume its due to the night-lightning situation as the lanes are recognized by camera. It was still good enough.
Of course curvy roads become a challenge at some point and smaller townstreets with no markings but given the collaborative approach, it felt natural to just take over steering completely if needed. The whole experience was always very seemles.
I still have to learn better how the automatic deleration in curves work - I had situations were it tried to speed with 150kmh through some curves I would have driven slower so it doesnt feel 100% reliable.


FYI LKA was a non issue to me - just happened a few times in very wild roads. People complaining about LKA should probably check their signaling habbits first.

 

A week is still very short. You will get a lot more used to it over time. If you have never used it, it feels like the car is fighting you but that's only because you are not used to it and you are overcorrecting. That's how I felt first and how others feel, too. Many also initially think that the car is not centered, whereas in reality they are used to driving off-centered when they drive manually.

I wish I could test TSS 3.0. TSS 2.0 is good but has some issues. Nevertheless, I am not going to spend a lot of money for an upgrade at this time. So, have you got your Gen 5 now? You haven't updated your information.

 

I actually did not feel like that at all - you might have misread my post? I was writing about collaboration and the car just assisting while always giving me the feeling to have the upper hand. Given what people write here I was expecting much worse though (like you described)

Perhaps you can test any other Toyota for a while?

Unfortunately I dont have the Gen 5 - no special treament for me Until it arrives I got a permanent loaner (new CHR, gen 2) though that is more or less technical identical to a Gen 5. It even has exactly the same multimedia screen size and only minimal changes in top trim (e.g. no ventilated seats) besides differences in overall form factor. Having tried a different loaner first allowed me to compare the capacitive vs torque based steering wheel.

 

No, I read it correctly and saw that you liked it. I was pointing out that you would like it even more in time.

There is not much point in for me testing TSS 3.0, other than satisfying my curiosity. I am not buying a new car at the moment, as mine is only three years old, and I want to be without car payments for a while.