Drive-By-Wire (DBW) Throttle Control May Be Joined By DBW Steering Soon

xcel · #1 10-26-2012, 12:59 AM

Nissan’s next generation steering control is DBW system with a mechanical link backup.

Wayne Gerdes - CleanMPG - Oct. 26, 2012

A conventional steering system directs tire movements by transmitting the drivers steering inputs to the tires via a mechanical link through either a hydraulic, electro-hydraulic or electric power assist system. Nissan's next-generation steering technology reads the driver's intentions from steering inputs and controls the vehicle's tire movements via electronic signals exclusively much the same way most modern day automobiles throttles are controlled entirely by electric signals vs. a mechanical link between the pedal and throttle plate.

The system not only mechanically steers the car but also insulates the driver from unnecessary road-generated disturbances providing only necessary feedback to the driver as the tuner sees fit.

Just as the video depicts, consider a road surface with minor ridges, rain grooves or bridge decks where you have to grip the wheel a little tighter and in some cases actually counter steer to avoid tramlining. With the DBW steering system, you should not have to grip the steering wheel as tightly and driving your intended path becomes much easier.

Accompanying this next-generation steering technology, Nissan has also developed a camera-based straight-line stability system to further enhance on-center driving capability.

This system is a world-first technology that improves vehicle stability by making small input angle adjustments so the vehicle will accurately trace and continue as planned in the lane it is traveling.

If the vehicle direction changes due to road surface or crosswinds, the system acts to minimize the effect of these conditions resulting in reduced steering input from the driver.

This next-generation steering technology's high reliability is achieved by multiple ECUs. In the event a single ECU malfunctions, another ECU will instantly take control. What I was mostly concerned with is a FAS. Intended or not. In this case, as the power supply is disrupted, the backup clutch will act to connect the steering wheel and wheels mechanically, ensuring continued steering control until the system is reset and powers up to control steering inputs entirely by the electronics again.

At first I thought it was a money saving direction but with the mechanical link and redundant systems, this one looks to add steering tuning but cost more due to the additional HW and SW involved.

In any case, do you want to steer by wire or mechanically like we have been doing for well over a century?

RichXKU · #2 10-26-2012, 01:37 AM

I think the steering wheels are already becoming sentient without DBW

http://www.youtube.com/watch?v=MLHWgAmx3Iw

http://www.youtube.com/watch?feature...DZAvVEYw#t=30s

http://youtu.be/hSbjgXbDUzo

WD-40 · #3 10-26-2012, 08:46 AM

You have to wonder how the steering will react to a tire blowout, especially if the driver is already used to not having the usual semi tight to tight grip on it.
I foresee a ton of lawsuits and recalls ..
Just my opinion, I'll stick to real mechanical stuff.
I Had an '07 Yaris with DBW throttle ... not impressed at all with the response time, very laggy.

PaleMelanesian · #4 10-26-2012, 08:56 AM

I'm not so sure about this. Something about a mechanical connection just seems like a good idea. Even if power steering fails, even if the engine fails, even if... you can still manage some steering. Throttle-by-wire is ok because throttle is less critical to basic survival.

xcel · #5 10-26-2012, 09:57 AM

Hi All:

There still is a mechanical connection that is declutched for the DBW system. If power is lost (I wonder how that could happen

), the clutch releases and you are back to good ole fashion mechanical steering w/out assist.

Wayne

PaleMelanesian · #6 10-26-2012, 10:04 AM

Oh, I see that now in the article. That's better. What exactly is this solving, then?

xcel · #7 10-26-2012, 10:44 AM

Hi Andrew:

Namely, tramlining and isolation from road perturbations with tuning to give you road feel feedback. The latest EPS systems are pretty good for feedback and the ability to remove any roughness would be another good idea. I do not see how this would save saves $'s however?

Wayne

CRT1 · #8 10-26-2012, 12:33 PM

I don't see how this is something that we need. Maybe ok for the luxury segment where there is a ton of superfluous stuff anyway, but for the bulk of the market, no thanks.

diamondlarry · #9 10-26-2012, 01:15 PM

I thought the Gen2 Prius' already had this? I saw a show where some people were driving a Prius with a laptop and eventually developed a system where they were able to have it drive through a town...with no driver behind the wheel.

xcel · #10 10-26-2012, 01:23 PM

Hi Larry:

You can drive the EPS through the wheel electronically as that is used in the current Park Assist systems. What the Nissan system does is sever the tie between the steering shaft and steering rack with a clutch so that all inputs are performed electronically with no mechanical interaction.

This is what is new about this system.

While EPA not only saves fuel, it is also less expensive. This system however looks to cost more with more "stuff" added (read more weight and complexity) only to remove any unintended road feedback.

Wayne