greggertruck

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Wow!! Clearest rear wheel steering video I’ve seen yet!




Tesla Cybertruck Rear-Wheel Steering showcased in Cybertruck pre-production beta prototype video WOW cybertruck rear wheel steerin
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Gurule92

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Sooo many pics and vids! I need my truck
 
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greggertruck

greggertruck

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KrodEKid

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Just spit-balling here...

Does anyone have an idea how a driver would operate this function? As most of the Tesla vehicle interiors are button free, I imagined it could be a control in UI settings, but this could be cumbersome. Trying to operate UI and steering wheel while navigating a tight turn in a busy parking lot could be stressful.

I imagine the operation could programmed to be activated by the steering wheel in the right conditions. Low speed, steering at or near lock, then the back wheel turns to decrease turn radius. It could be initiated by increased tension on steering wheel as a haptic feedback to let you know your in 4 wheel steering.

Crab walk type 4 wheel steering would be a little more tricky to operate. Vehicles aren't designed to moved this way and it's applications may not be readily apparent. Would it be practical to use to change lanes at high speeds or would that be dangerous? Would it be used it towing hitch alignment or assist in reverse while towing? I think obstacle avoidance for rock crawling would be more low yield than these other use cases.

I know there could be as many applications as people using the car but what will yield the most practical and common applications for crab walk type 4 wheel steering? Crab walk seems more gimmicky to me than other type 4 wheel steering.
 

sstevens805

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Just spit-balling here...

Does anyone have an idea how a driver would operate this function? As most of the Tesla vehicle interiors are button free, I imagined it could be a control in UI settings, but this could be cumbersome. Trying to operate UI and steering wheel while navigating a tight turn in a busy parking lot could be stressful.

I imagine the operation could programmed to be activated by the steering wheel in the right conditions. Low speed, steering at or near lock, then the back wheel turns to decrease turn radius. It could be initiated by increased tension on steering wheel as a haptic feedback to let you know your in 4 wheel steering.

Crab walk type 4 wheel steering would be a little more tricky to operate. Vehicles aren't designed to moved this way and it's applications may not be readily apparent. Would it be practical to use to change lanes at high speeds or would that be dangerous? Would it be used it towing hitch alignment or assist in reverse while towing? I think obstacle avoidance for rock crawling would be more low yield than these other use cases.

I know there could be as many applications as people using the car but what will yield the most practical and common applications for crab walk type 4 wheel steering? Crab walk seems more gimmicky to me than other type 4 wheel steering.
I'm thinking it would be speed dependent for the most part. Below 10 and they turn in opposition to make tight maneuvers easier. And then above a certain point they turn in the same direction to increase stability during lane changes. For crab walk and other things I guess the screen would be the key, some setting like carwash mode or maybe an off-road mode. But definitely not a button like GM's Quadrasteer .
 

cvalue13

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Maybe not much more.

it only shows when the front are turned all the way, tho. Kinda like ai predicted; that would make it drive more like other trucks usually.

-Crissa
Yea, if the CT retains the originally-stated enormous wheelbase, it may need this feature just to have a competitive turning radius.

Maybe only if the wheelbase-to-length has narrowed, would this give a turning radius advantage
 

MC1987

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It could also be sensor driven. In the wiring picture, CT has these circular things at the corners. These could be the sensors that feeds into the rotation part.
 

charliemagpie

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Seamless

Seamless in the sense of the 99.9999% of situations we find ourselves in... the car AI will know what we want before we know it ourselves.

Elon said Dojo will be an order of magnitude faster this year, and perhaps improve another order of magnitude next year.

Just recently they showed that once multi hour/days process now takes Dojo 5 minutes... we could hypothetically reduce that to 30 seconds this year, and down to 3 seconds next year.

The car will have already done what we think is an exception a million times.

If needed, we can just ask the car to do it, using conversation.

No FSD needed. Just driver assist.
 


Ogre

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When humans are controlling the steering, the steering will be a deterministic algorithm, not set by an AI on the fly. They might use AI to create those algorithms, but it will be straight forward so it’s predictable. It would be incredibly frustrating to turn the wheel while reversing and have it *sometimes* do one thing unless the computer thinks you need it do do something else.

When FSD is in control, it might be a whole other story and do whatever it needs to get you where you need to go.
 

JBee

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4WS is not a new technology. It has been around for decades. Even my tractor has it. They typically operate in two distinct modes based on the vehicle speed.

Mode 1 is for lower speed manevouring, up to 20-30MPH, and is where the rear wheel angle is opposite to the front steering angle, for a higher rate of vehicle yaw, and smaller turning radius than without 4WS. The amount of steering angle is of course also proportional to the front steering, in that the rear wheels will intentionally try to more closely follow the front wheel track. The amount of rear angle is more at low speeds and gets less until it reaches the higher speed, at which it switches over to mode 2.

Mode 2 is for highway cruising and operates at highway speeds by steering in the same direction as the front axle. (Crab steer but angle constrained). This allows the vehicle to change lanes without yawing and stay mostly parallel with the directionof travel and the lanes.(yaw-twisting out and into the lane as seen from above). Yaw motions are what create load change moments, and also suspension changes and traction offsets. Avoiding this keeps the vehicle more stable on lane changes and greatly assists in mitigating tow vehicle (and driver) induced trailer oscillations.

All of these variables would be tuned to match vehicle dynamics, and then again for towing profiles, or even terrain and specific road conditions. They would also be linked into dynamic suspension setup, and ABS and torque vectoring profiles.

Another point worth mentioning is that the steering angle of the rear axle does not have to be much to do all these things, or improve the turning radius, so they won't have much rear steering angle. This also means that if the rear steering fails at any point, the front steering angle range will be able to compensate for a rear angle lock up, meaning you can still maintain control of the vehicle until you can come to a stop and pull over.

For the driver all these things happen seemlessly behind the scenes, and requires no user input in normal operation, except to turn the front wheel. The only thing you will notice as a user, if you are looking for it, is that the center of rotation of the vehicle will change position. On a front wheel steer vehicle this is inbetween the rear axle wheels. So depending on how much rear steering angle is being contributed in Mode 1, this point of rotation will move forward towards the middle of the CT. In Mode 2 it will actually move back, and can be behind the vehicle itself. Which is also why it has better towing stability as well, as the car "acts" as if it where a two front steered axle truck, and slews the trailer accross the lane.
 
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Bill906

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Let‘s say the speed threshold that decides the steering mode is 25MPH. What will it do if I start a going around a corner at 20MPH but while in the corner I accelerate to 30MPH?

OH! Or... I’m on the Highway going 50MPH and changing lanes. A deer jumps out in front of me and I hit the brakes and swerve.

I’m not looking for an answer. Just sharing my thought process. 4 wheel steering Is probably way more complicated than we realize.
 

Ogre

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Let‘s say the speed threshold that decides the steering mode is 25MPH. What will it do if I start a going around a corner at 20MPH but while in the corner I accelerate to 30MPH?

OH! Or... I’m on the Highway going 50MPH and changing lanes. A deer jumps out in front of me and I hit the brakes and swerve.

I’m not looking for an answer. Just sharing my thought process. 4 wheel steering Is probably way more complicated than we realize.
This is why I say it must me deterministic.

No guesswork.

Personally, I think there will need to be a large between zone. 0-20 MPH it is opposite/ parking lot/ minimum turn radius mode. 20-50 is neutral rear wheels. 50+ is highway mode.

Just an example. Experts would have more specifics.
 

Bill906

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This is why I say it must me deterministic.

No guesswork.

Personally, I think there will need to be a large between zone. 0-20 MPH it is opposite/ parking lot/ minimum turn radius mode. 20-50 is neutral rear wheels. 50+ is highway mode.

Just an example. Experts would have more specifics.
Agreed. Also suspect a force to neutral during high acceleration or deceleration. Like in my deer example. Also probably code that says do not enter, leave or change modes when front wheels are not pointed straight.
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