Actual Off-Road Testing: climbing & descending (@ Hollister Hill RSVA - 10/23/23)

[JBee]

Guys and gal's...

Even if the Dual motor had super fast motor control it still has two open diffs which can only be modulated with brakes if it doesn't have a locker.

So are we arguing about something the CT might never have?

Maybe, Tesla knows about the QM off road problems?

And regardless of the motor control method, or how fast it is, it's still not the same as a locker. Simply because the individual motors need to modulate torque depending on traction with a QM to maintain RPM and forwards momentum, whereas a locker doesn't.

There's also a reverse argument to be made here, which seanrarey also highlighted, and that is there are some situations you actually want open differential so it doesn't torque steer, and break traction because "it thinks" you don't want wheel slip in a QM, that only has software diffs that can't tell the difference.

Hence his argument to get a DM CT with open diffs.

A simple example here is going downhill in low range in the right gear to maintain decent speed instead of using the brakes.

If you don't know the difference you absolutely don't know what you are talking about.

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[JBee]

I said, "Let's remain logical here", not "Let's try to create the appearance you knew what you were talking about all along"!

It sounds like you have more money than brains!

Could you stop with the constant ad-hominem personal attacks?

Are you really that fragile that you have to hit out EVERY technical discussion we have?

Let alone to new posters that actually have some relevant technical input, beyond your fanboi tirade?

It's exhausting.

Stay on subject, discuss the topic, and leave your insults for your "real" friends.

The quest here is to share information.
So can we do more of that please?

 

[HaulingAss]

Could you stop with the constant ad-hominem personal attacks?

Are you really that fragile that you have to hit out EVERY technical discussion we have?

Let alone to new posters that actually have some relevant technical input, beyond your fanboi tirade?

It's exhausting.

Stay on subject, discuss the topic, and leave your insults for your "real" friends.

The quest here is to share information.
So can we do more of that please?

Kettle. Pot. Black.

It's clear you didn't understand the misinformation I was correcting, it had nothing to do with a "fanboi" tirade and everything to do with pointing out that the fact that the Hummer and the Rivian don't demonstrate anything that simulates a locking differential does not imply that a motor in each wheel cannot effectively simulate a locking differential. One cannot prove that something is impossible simply because there are no known examples of it being done. Nothing to do with Tesla at all.

What's exhausting is your insistence that the 3mm panels on the exterior of the Cybertruck are not stuctural, even though all the information we have says they are, and it's pretty obvious that your personal attack on me is in direct response to me calling out the way in which you are jumping to false conclusions with no supporting evidence. Let's keep it real.

 

[cyberhunter]

All I really want is to be able to use the CT like my Ram Diesel 4WD. That means I can put it in 4wd high with traction control on by default. I want the ability to turn traction control off, because steep incline, caliche, rocky, or deep dirt roads with or without heavy rain will quickly show how traction control can be a negative. I've had traction control absolutely almost get me stuck because I needed to keep momentum and it was robbing me of power and slowing me down no matter how much throttle I gave it. I also want to be able to put it in 4wd low, locking the differentials because I have been in situations just traveling back country roads after a heavy rain where I needed those differentials to be locked and I needed to be able to keep the wheels going (all of them, regardless of spin) just to keep momentum. I also like the extra torque and control that 4wd low gives me. My hopes for CT were that it could give me these modes, plus the ability to control suspension height, have 4 wheel steering to help in low speed turn radius situations, and control the suspension stiffness based on the type of driving I am engaged in at the time. I was hopeful that I could get good control over power to the ground and combined with the BEV inherent good weight distribution and low COG, get a great driving truck on back country roads as well as on road manners. Seeing the tires barking badly on that hill give me pause that it will perform like I have seen Rivian and Hummer EV (not great). I'm still hopeful, but that is fading some.

 

[CyberDogeGuy]

Cybertruck spotted offroad testing just now by @dima Zeniuk

Videos of climb:

What that hill looks like (posted by @Bill837 below)

Other pics:

Cybertruck spotted offroad testing just now by @dima Zeniuk

Videos of climb:

What that hill looks like (posted by @Bill837 below)

Other pics:

30 seco

Cybertruck spotted offroad testing just now by @dima Zeniuk

Videos of climb:

What that hill looks like (posted by @Bill837 below)

Other pics:

The only thing I can see in the second video starting at 30 seconds is that infuriatingly childish BAW. It is SOO un-Tesla-like and a truly un-inspired design decision. Yeah, yeah, defend it if you like but I hope it is removable so I can toss that Neanderthal, fugly-stick in the truck bed. Ugh. C’mon Elon, Seriously?

 

[JBee]

Kettle. Pot. Black.

It's clear you didn't understand the misinformation I was correcting, it had nothing to do with a "fanboi" tirade and everything to do with pointing out that the fact that the Hummer and the Rivian don't demonstrate anything that simulates a locking differential does not imply that a motor in each wheel cannot effectively simulate a locking differential. One cannot prove that something is impossible simply because there are no known examples of it being done. Nothing to do with Tesla at all.

What's exhausting is your insistence that the 3mm panels on the exterior of the Cybertruck are not stuctural, even though all the information we have says they are, and it's pretty obvious that your personal attack on me is in direct response to me calling out the way in which you are jumping to false conclusions with no supporting evidence. Let's keep it real.

Huh lol.

I don't have a problem discussing the physics of exoskeleton.
Lets start a new thread if you're ready to bring round 69 to the table with some facts!
I'm sure the others will enjoy our compliment slinging contests!

I'm not complaining about the rocks you throw my way here, hence my comment about "real" friends. That's why I respond to you in particular in kind, because you are "that guy" that needs it most, and that's how you vibe bro.

My problem is when you chase away posters because you can't help getting out your fanboi stick. Who needs that as the forum reception committee? Tesla doesn't have a monopoly on physics, or the engineers that use it.

Your last post above is a classic example: Don't you think Rivian that spent a few billion on making it, didn't "manage" to simulate a differential lock in software with their QM?

If so, then please explain how they manage to get the QM Rivian to drive straight down the road, without torque steering all over the place under heavy acceleration?

So maybe they do have it, the question is does it work well with low states of vehicle inertia on the cusp of tyre traction and nearly zero RPM? "Ah, I see", said the blind man.

Reality is dynamic, not a fixed point in space that orbits around you.

 

[HaulingAss]

Huh lol.

I don't have a problem discussing the physics of exoskeleton.
Lets start a new thread if you're ready to bring round 69 to the table with some facts!
I'm sure the others will enjoy our compliment slinging contests!

I'm not complaining about the rocks you throw my way here, hence my comment about "real" friends. That's why I respond to you in particular in kind, because you are "that guy" that needs it most, and that's how you vibe bro.

My problem is when you chase away posters because you can't help getting out your fanboi stick. Who needs that as the forum reception committee? Tesla doesn't have a monopoly on physics, or the engineers that use it.

Your last post above is a classic example: Don't you think Rivian that spent a few billion on making it, didn't "manage" to simulate a differential lock in software with their QM?

If so, then please explain how they manage to get the QM Rivian to drive straight down the road, without torque steering all of the place under heavy acceleration?

So maybe they do have it, the question is does it work well with low states of vehicle inertia on the cusp of tyre traction and nearly zero RPM? "Ah, I see", said the blind man.

Reality is dynamic, not a fixed point in space that orbits around you.

Boring!

 

[JBee]

Boring!

Proof!

 

[FutureBoy]

and no I'm not going to take the MY off road to prove anything

Can WE take your MY off road to prove something? It would save you the trouble...

 

[FutureBoy]

can only be modulated with brakes

The majority of Tesla braking is being done through regen instead of classic brakes.

 

[JBee]

All I really want is to be able to use the CT like my Ram Diesel 4WD. That means I can put it in 4wd high with traction control on by default. I want the ability to turn traction control off, because steep incline, caliche, rocky, or deep dirt roads with or without heavy rain will quickly show how traction control can be a negative. I've had traction control absolutely almost get me stuck because I needed to keep momentum and it was robbing me of power and slowing me down no matter how much throttle I gave it. I also want to be able to put it in 4wd low, locking the differentials because I have been in situations just traveling back country roads after a heavy rain where I needed those differentials to be locked and I needed to be able to keep the wheels going (all of them, regardless of spin) just to keep momentum. I also like the extra torque and control that 4wd low gives me. My hopes for CT were that it could give me these modes, plus the ability to control suspension height, have 4 wheel steering to help in low speed turn radius situations, and control the suspension stiffness based on the type of driving I am engaged in at the time. I was hopeful that I could get good control over power to the ground and combined with the BEV inherent good weight distribution and low COG, get a great driving truck on back country roads as well as on road manners. Seeing the tires barking badly on that hill give me pause that it will perform like I have seen Rivian and Hummer EV (not great). I'm still hopeful, but that is fading some.

That's also why most serious off-roaders with low range and the like, come from the factory with a traction control/ESP off switch. It's impossible to maintain momentum in beach sand with traction control cutting throttle and not letting you spin the wheels!

In the soft sand the wheels need to spin in order to create forward thrust.
Another win for a locker...because you can put power down without worrying about being slowed down at any RPM or speed.

It's important to realize that different surfaces require different operational modes, hence the "mode" on modern 4x4's to better fit driving surfaces and changing traction dynamics.

 

[JBee]

The majority of Tesla braking is being done through regen instead of classic brakes.

You miss the point, how do you get one wheel to spin that has traction, and the other one that has no traction (and is spinning) to stop using "regen" and not the brakes, if you have an open differential, and only one motor driving both wheels? The context is traction control on a DM that uses the brakes to maintain traction on the same axle as one motor.

 

[FutureBoy]

You miss the point, how do you get one wheel to spin that has traction, and the other one that has no traction (and is spinning) to stop using "regen" and not the brakes, if you have an open differential, and only one motor driving both wheels? The context is traction control on a DM that uses the brakes to maintain traction on the same axle as one motor.

So many specifics…. Too many for me to care.

 

[GuyV]

Reality is dynamic, not a fixed point in space that orbits around you.

Exactly, meaning that just because you can't see how a thing can be done doesn't mean someone else can't figure out how to do it.

 

[JBee]

Exactly, meaning that just because you can't see how a thing can be done doesn't mean someone else can't figure out how to do it.

So tell me then how to make traction control not "reactionary"?

There are physical limits, and "theoretical limits". Then there are theoretical limits based on false authority.

Lots of theoretical limits fail when they meet physical limits.

First up you would have to tell me about how a motor inverter controls rpm and torque, then we could discuss "how to fix it", because then we are talking about the same limitations.

Take a look at how "tesla" does it:



It's pretty decent for the conditions, but it has slip before the brakes engage, and that is with two wheels worth of perfect grip, not four with alternating levels of grip. You would think that after decades in the field and in the age of OTA they would know how to "fix it" by now?

So this is exactly what a DM setup will do in the CT that only has the ability to use the hydraulic brakes and traction control to control wheel slip. The only way to improve it is for a DM is to have better brakes that can be dosed so fast and accurately that they can simulate a locker....or simply have a locker.

Now a tri motor CT will be able to control the rear two wheels better, because it has a motor each, meaning it can modulate power for each rear, and a QM even better again with the front, but all will have a "delay" between when the wheel traction changes the torque that can applied to the contact patch of the tyre, and that the motor can respond in kind.

You can see how the wheels all produce varying levels of rotation here, where only one or two wheels are propelling it and then breaking traction. There is never a case it has 4 wheels turning at the same time with traction. Each time one wheel breaks traction it forces more load on the next until that breaks and so on. The cascade creates less effective traction, because one wheel is working against the other, instead of all together.



In comparison a locker act like a "tank track" in that all the tracks move at the same speed and the same torque, even if half of the same track is on ice (no friction) and the other half on solid ground (friction).

So if you want to discuss how, then please first define which motor version you would like to discuss the theoretical limits of, and what constraints or tests you wish to perform to recreate a simple diff lock.

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