Tri-Motor Cyber Turn?

[Turtle]

I have had some questions about the Cyber Trucks turning radius. I would expect it to be in the same range as a Ford F-150 Super crew or the like.
After watching Todd TheCyberTruck TruckGuy video the other night, I was thinking it might be cool if the tri-motor could make tractor turns to tighten the turning radius in unique situations. This could be an answer to the Rivian’s Tank turn. Maybe it could be called the “Cyber Spin” ! What do you think? Does it make sense? Is there a need, and could it be done?

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[cybertrucktruckguy]

I have had some questions about the Cyber Trucks turning radius. I would expect it to be in the same range as a Ford F-150 Super crew or the like.
After watching Todd TheCyberTruck TruckGuy video the other night, I was thinking it might be cool if the tri-motor could make tractor turns to tighten the turning radius in unique situations. This could be an answer to the Rivian’s Tank turn. Maybe it could be called the “Cyber Spin” ! What do you think? Does it make sense? Is there a need, and could it be done?

Well you already know my opinion.

 

[Sirfun]

Would it work better to do that in reverse? That way the turning wheels are in the back. A reverse 180, to back out of a tight spot on dirt?

 

[Turtle]

Would it work better to do that in reverse? That way the turning wheels are in the back. A reverse 180, to back out of a tight spot on dirt?

It may work in both directions. I would think one rear wheel stays stationary, while the others rotate. Not sure the CT is or could be designed to handle that stress/torque? Just thought I would add my 2cents.

 

[Sirfun]

Would it work better to do that in reverse? That way the turning wheels are in the back. A reverse 180, to back out of a tight spot on dirt?

It may work in both directions. I would think one rear wheel stays stationary, while the others rotate. Not sure the CT is or could be designed to handle that stress/torque? Just thought I would add my 2cents.

I would think that would be easy to do with the computer controls. It would probably be in FSD, the cameras look behind and calculate if there's enough room for the maneuver. It would give you a green light, saying that it's an option. You the driver select, "cyber turn" and which direction, left or right and the CT performs it, just like a parallel park. All it would have to do is back up at a set speed hit the brake on the appropriate rear wheel and crank the steering.
Actually in a dirt field this sounds like fun. Of course we wouldn't have access to one wheel braking. But it would be a fun maneuver to learn/perfect under the right circumstances. Empty snow covered parking lots can be fun too.

 

[Daweism]

Well you already know my opinion.

Hey it's the guy! ^

 

[lqdchkn]

... Is there a need, and could it be done?

Key question is this one.


Is there a need? Rarely IMO. Perhaps only in a few rare off road scenarios that I can think of.

Could it be done? Sure. Anything could be done, Id think only if the front has an open differential though.

 

[MO Truck]

I would think that would be easy to do with the computer controls. It would probably be in FSD, the cameras look behind and calculate if there's enough room for the maneuver. It would give you a green light, saying that it's an option. You the driver select, "cyber turn" and which direction, left or right and the CT performs it, just like a parallel park. All it would have to do is back up at a set speed hit the brake on the appropriate rear wheel and crank the steering.
Actually in a dirt field this sounds like fun. Of course we wouldn't have access to one wheel braking. But it would be a fun maneuver to learn/perfect under the right circumstances. Empty snow covered parking lots can be fun too.

Sounds like a cyber donut

 

[Sirfun]

Sounds like a cyber donut

Sounds better than a Cyber roll. ?

 

[Warner69]

You would only want to do a tractor turn on dirt or similar surface. Doing this on payment will shred tires and place high stress on the drive train. I've driven many tractors and doing this type of turn on pavement is not advisable.

 

[Luke42]

You would only want to do a tractor turn on dirt or similar surface. Doing this on payment will shred tires and place high stress on the drive train. I've driven many tractors and doing this type of turn on pavement is not advisable.

Traditional locking 4x4 systems used on dry pavement have this problem, too, even with normal steering.

This is actually a big problem for me on the paved roads with patchy winter weather I encounter. I chose a truck with a not-so-cleverly-disguised AWD system (GMC Sierra) over a traditional 4x4 (most F-150 variants) in order to solve this problem.

The Cybertruck designs away the many of the issues of traditional 4x4 systems by having multiple motors (and presumably LSDs of some sort or another).

 

[ajdelange]

There is no need for any differential if there be independent motors on a wheel pair. A wheel pair driven by a single motor obviously does need a differential. Tesla evidently is able to overcome differential slip simply by sensing that one wheel is going faster than the other, removing the torque from both (i.e. the motor) and then reapplying torque. This is, to me, at the level of a rumor. I don't see how it could work effectively. A limited slip differential is one in which the torque is directed more or less to one wheel or the other. This can be achieved with an ordinary differential just by applying the brake to the wheel to which you want reduced torque. This is, of course, lossy. But limited slip differntials have cones or hydraulic couplings or clutches or something like that which are also lossy.

 

[Crissa]

Tesla uses the motor pair to create different optimal torque to power consumption. One motor is tuned to high speed, the other is tuned to low. The vectoring between the two creates a wider effective range of speeds at high power. It also spreads out heat generation at high demand.

They don't specifically drive wheels independently. That's what the brakes are used for.

-Crissa

 

[Luke42]

There is no need for any differential if there be independent motors on a wheel pair.

This is true for a quad-motor truck, like the Rivian S1T, where each wheel is driven by an independent motor. No differentials required.

The Tesla truck has no quad-motor variation. It will have differentials of some sort in all motor configurations.

The software driven limited-slip differential that you describe (using the ABS sensors and break controls to limit wheel-spin) will work well in the all weather / softroading use case I have. The software+brake approach seems like an obvious fit for the Cybertruck. But many vocal members of thr offroad community seems to prefer more traditional mechanical lockers and LSDs. For most trucks, the type of differential would depend on what kind of customer they're trying to impress. I'll be interested to see what approach Tesla ultimately chooses.

I've found through experimentation that computer controlled slip & grip stuff to be ideal for *my* use-case. But not everyone uses their truck the same way. [shrug]

 

[alan auerbach]

I have had some questions about the Cyber Trucks turning radius. I would expect it to be in the same range as a Ford F-150 Super crew or the like.
After watching Todd TheCyberTruck TruckGuy video the other night, I was thinking it might be cool if the tri-motor could make tractor turns to tighten the turning radius in unique situations. This could be an answer to the Rivian’s Tank turn. Maybe it could be called the “Cyber Spin” ! What do you think? Does it make sense? Is there a need, and could it be done?

"Tractor turn" means you crimp the fronts to full turn (a lot) and brake one rear, allowing the tractor to turn in almost its own length. You may have meant "tank turn" or "skid steer," in which the drivers on one side hold still or even reverse while the other side moves, allowing in-place spinning. (The third option is caster steering, in the the rears power differentially while the fronts are in caster mode. Common in zero-turn mowers but not aware of its application to road vehicles.)

Either could be offered with fly-by-wire steering, but the longer the wheelbase the less the effectiveness, and the CT's wheelbase looks to be quite long. Adding rear steering and crab mode would be more practical.