Turning radius update to come! Extra 7 degrees of steering angle for rear wheel steering (from 3 to 10 degrees)

[Maaz]

it actually wasnt

this is an 11th hour change by guess who

Lars and Franz mentioned it would eventually allow 10 degrees of rear steer in the top gear cybertruck video.

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[cvalue13]

You and I are saying different things. I think you are talking original design. What I am saying is the “hardware” is capable of 10 degrees and so the software is key to opening the ability when they are ready. Regardless of when the change was made to the physical pieces and parts, it left the factory with the capability. The opposite of my point would be that the bushings and wheel well only support 3 degrees and if you take it in to the service center, they will swap stuff out and give you 10 degrees. Sound better?

got it ??

Lars and Franz mentioned it would eventually allow 10 degrees of rear steer in the top gear cybertruck video.

?

 

[charliemagpie]

43.5ft (13.26m) current turning radius

What would the turning radius be if it was 10 degrees? Asking too much?

 

[Diveflyfish]

It may be of interest to see if Tesla could speak to the use of this type of electrochemical passivation device to create a homogenous uniform passivation layer : https://www.fronius.com/en-us/usa/w...ual-welding/tig/magiccleaner/magiccleaner-150

 

[Crissa]

Ooops inadvertent wrong thread! Sorry!

You're allowed to delete posts.

-Crissa

 

[FarAway]

Audi offers AWS as an option on the Q7, they call it Quattrosteer. It allows for up to 5deg of turn for the rear wheels and will reduce the turn radius by 3.3'. It is amazing how easy it makes backing up a trailer.

From Audi:
Jan 11, 2019
Audi dynamic all-wheel steering. At speeds up to 60 km/h (37.3 mph), the rear wheels are turned as much as five degrees in the opposite direction in relation to the front wheels. This reduces the turning circle by up to one meter (3.3 ft) to 11.1 meters (36.4 ft), virtually on a par with the A3. At medium and high speeds, the wheels are turned by as many as two degrees in the same direction. Consequently, new Audi's equipped with AWS are even more stable on the road and also perform abrupt evasive maneuvers with composure.

 

[charliemagpie]

If you need hundreds of thousands of miles I am confused on why you would need hundreds of thousands of Cybertrucks on the road to gather that many miles?

Because they are all towing

 

[TickTock]

43.5ft (13.26m) current turning radius

What would the turning radius be if it was 10 degrees? Asking too much?

[Edit] This is not correct - assumes the length of side a doesn't change when the rear steering angle changes. Not correct. See the later post which corrects for this.[/Edit]
I'll take a stab. Fun geometry problem.

Drawing a triangle from the center of the front and rear outer wheel and the center of the circle and using the law of cosines (twice) and assuming the front outside wheel is what defines the circle, I get 40.8 feet.

a=distance from rear wheel to circle center
b=distance from front to rear wheels (12.6 ft)
c=distance from front wheel to circle center (currently 21.75 ft)
gamma=angle of rear wheel axle

1) a=?, b=12.6, c=43.5/2, gamma=90-3=87deg and solving for a gets a=18.4
2) a=18.4, b=12.6, c=?, gamma=90-10=80deg and solving for c gets c=20.4. Twice that is the new turning circle. 40.8 feet.

 

[Coltpete]

I'll take a stab. Fun geometry problem.

Drawing a triangle from the center of the front and rear outer wheel and the center of the circle and using the law of cosines (twice) and assuming the front outside wheel is what defines the circle, I get 40.8 feet.

a=distance from rear wheel to circle center
b=distance from front to rear wheels (12.6 ft)
c=distance from front wheel to circle center (currently 21.75 ft)
gamma=angle of rear wheel axle

1) a=?, b=12.6, c=43.5/2, gamma=90-3=87deg and solving for a gets a=18.4
2) a=18.4, b=12.6, c=?, gamma=90-10=80deg and solving for c gets c=20.4. Twice that is the new turning circle. 40.8 feet.

Thank you for calculating this. This seems like a pretty big waste just to save a foot and a half of turning radius no? I'm sure it's more useful for backing in and tight spaces too but still. Alot of effort was required to design and apparently create the software for the rear wheel steering

 

[TickTock]

Thank you for calculating this. This seems like a pretty big waste just to save a foot and a half of turning radius no? I'm sure it's more useful for backing in and tight spaces too but still. Alot of effort was required to design and apparently create the software for the rear wheel steering

Using the same formula, the circle would have been 44.6 ft with no rear steer so it buys us more than 1.5ft - almost 4 ft. Doesn't seem like much but I think it makes a big difference - I usually just miss a U-turn only by foot or so. However, It is a shame they couldn't get into the 36' range - typical for smaller passenger cars. THAT would have been some bragging rights!

 

[Coltpete]

Using the same formula, the circle would have been 44.6 ft with no rear steer so it buys us more than 1.5ft - almost 4 ft. Doesn't seem like much but I think it makes a big difference - I usually just miss a U-turn only by foot or so. However, It is a shame they couldn't get into the 36' range - typical for smaller passenger cars. THAT would have been some bragging rights!

I was basing this on the above post which said 43.5 ft is the current turn radius. I'll have to look up what the actual specs are, I'm sure this is out there somewhere.

 

[TickTock]

I'll take a stab. Fun geometry problem.

Drawing a triangle from the center of the front and rear outer wheel and the center of the circle and using the law of cosines (twice) and assuming the front outside wheel is what defines the circle, I get 40.8 feet.

a=distance from rear wheel to circle center
b=distance from front to rear wheels (12.6 ft)
c=distance from front wheel to circle center (currently 21.75 ft)
gamma=angle of rear wheel axle

1) a=?, b=12.6, c=43.5/2, gamma=90-3=87deg and solving for a gets a=18.4
2) a=18.4, b=12.6, c=?, gamma=90-10=80deg and solving for c gets c=20.4. Twice that is the new turning circle. 40.8 feet.

[Edit]
I don't think this is accurate either since it assumes the *outer* rear wheel angle increases from 3 to 10 degrees. That would mean the inner rear wheel has to turn more than 10. So I recalculated based on the inner wheel being limited to 10 degrees and now get 38.95ft
[/Edit]
Hmmm. I think it is better than that. I now realize I had a false assumption in this method. a is not the same when you change the rear steering angle. Here is my new method:
1) LOC (Law of Cosines) to find a (distance to rear wheel)
2) LOC to find the max steering angle of the front wheels
3) LOS (Law of Sines) to find the new distance to the front wheels

1) a=?, b=12.6, c=21.75, gamma=90-3=87deg and solving for a gets a=18.4
2) a=18.4,b=12.6,c=21.75, alpha=? and solve for alpha (angle at front wheel) gets alpha=56.7 deg
3) Beta, then, is 180-56.7-87=35.3 degrees
4) changing rear wheel angle to 10 makes Beta=42.3
5) using law of sines, c=sin(80)*12.6/sin(42.3)=18.4ft !!!

New turning radius is 36.8ft! Now we're talking!

I welcome peer review.

 

[Jethro]

I absolutely hate these robot readers with static pictures.

Yes, stolen from Ryan Shaw’s video with nothing new….like WHAT THE NEW TURNING RADIUS WILL BE????

 

[Jethro]

Hmmm. I think it is better than that. I now realize I had a false assumption in this method. a is not the same when you change the rear steering angle. Here is my new method:
1) LOC (Law of Cosines) to find a (distance to rear wheel)
2) LOC to find the max steering angle of the front wheels
3) LOS (Law of Sines) to find the new distance to the front wheels

1) a=?, b=12.6, c=21.75, gamma=90-3=87deg and solving for a gets a=18.4
2) a=18.4,b=12.6,c=21.75, alpha=? and solve for alpha (angle at front wheel) gets alpha=56.7 deg
3) Beta, then, is 180-56.7-87=35.3 degrees
4) changing rear wheel angle to 10 makes Beta=42.3
5) using law of sines, c=sin(80)*12.6/sin(42.3)=18.4ft !!!

New turning radius is 36.8ft! Now we're talking!

I welcome peer review.

Yep! I agree! nice work! I did a quickie in my head. If 3 degrees gave us about a 4’ improvement over no RWS then an increase of 7 degrees should give us another 7/3 x 4 = 9.3 feet decrease. For around 34.2 feet….wow! Much better than my MYP!

 

[rudedawg78]

You hope you'll not qualify for AARP before you get yours.

AARP's membership age requirement is actually only 18 years old. So....

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