: steer by wire



Crown Vic Owner
12-17-07, 12:51 AM
While, i drove a malibu with steer by wire. Is it me, or is it weird to drive these cars.


I have the rotten feeling that steer by wire is not safe at all. Thinking worst case scenario, if the car is steered electronically, what happens if it fails in the middle of a turn or the car dies, assuming its powered by power steering.


I will take my steering column thanks.

wait4me6920
12-17-07, 01:26 AM
Losing a hydraulic power steering pump can introduce pretty much the same sort of symptoms that one would experience with failed electric steering assist. (Mechanically electric and hydraulic power steering systems are very similar. Both systems merely assist a mechanical linkage, and both base systems still work if the power assist fails.)

Most cars today don't offer the option of purely manual steering, so you can expect that the steering feel is going to be heavy if the power assist goes away. The Chevy Malibu is a fairly heavy front-wheel drive car, so losing power steering is going to be a pretty significant event.

Interestingly enough, if you Google you'll find the NHTSA investigated complaints about failing power steering in the Malibu and found it wasn't a widespread problem, nor did the failure mode "Substantially limit the driver's ability to turn the vehicle in a particular direction or to provide the driver with unintended power assistance".

I simply don't like the feel of the electric assist... Disconcerting...

AMGoff
12-17-07, 01:28 AM
What the hell are you talking about? The Malibu doesn't have a "steer by wire" setup... there's still a steering column. There's a big difference between electronically assisted (in lieu of a pump) steering and "steer by wire."

... it's a Chevy, not a fighter-jet.

dkozloski
12-17-07, 01:35 AM
I saw a video of an AirBus with fly-by-wire flying through the trees because the computer wasn't doing what the pilot wanted it to do. That operation ended with a huge column of black smoke. http://en.wikipedia.org/wiki/A330_test_flight_crash

LS1Mike
12-17-07, 01:46 AM
My new Equinox has it, works like hydraulic steering but uses an electircal motor instead. If it fails just like losing the power steering pump.

Sinister Angel
12-17-07, 02:12 AM
I saw a video of an AirBus with fly-by-wire flying through the trees because the computer wasn't doing what the pilot wanted it to do. That operation ended with a huge column of black smoke. http://en.wikipedia.org/wiki/A330_test_flight_crash

Silly Airbus

Sinister Angel
12-17-07, 02:13 AM
While, i drove a malibu with steer by wire. Is it me, or is it weird to drive these cars.


I have the rotten feeling that steer by wire is not safe at all. Thinking worst case scenario, if the car is steered electronically, what happens if it fails in the middle of a turn or the car dies, assuming its powered by power steering.


I will take my steering column thanks.

Yellow journalism, what?

Hell, the facts weren't even right.

Red_October_7000
12-17-07, 04:33 AM
LOL true!

Want an experience? Try driving a 4,400-lb front-wheel-drive car with failed power steering! Not too too bad when it was moving, but I had to park it to put it away! I thought I was going to bend the wheel when I was parking it so the wrecker could come and get it!

ewill3rd
12-17-07, 09:20 AM
My '69 Camaro had manual steering and some bonehead replaced the steering wheel with one of those tiny 10" jobbers. Manual transmission, heavy duty mechanical clutch and some old Daytona white letters in a 60 series. Parking was quite a workout indeed!

It is electrically assisted, but it still has a mechanical steering column and gear.
Easy to get confused. We are a ways off from a drive by wire steering system. Although I understand that the new STS is available with a funky steering column that will allow the car to steer itself a few degrees to maintain stability.
Crash avoidance here we come!


Active Front Steering Description and Operation
Active Front Steering
The active front steering (AFS) System will superimpose an angle on driver’s steering input via an electromechanical actuator between the steering wheel and steering gear. The motor controlled angle is based on the vehicle’s dynamic state. At all times, the mechanical link between the steering wheel and road wheels are maintained. The superimposed steering angle is not limited mechanically. It has as much authority necessary to achieve the desired vehicle dynamics. With this type of system, many benefits can be added to the functionality of the steering system; including continuously variable steering ratio and enhanced vehicle stability control. The system also provides the driver with tactile feedback of the external forces reacting against the front tires.

The AFS subsystem contain the following major components:

Active front steering actuator
Power steering control module
Motor and signal harness between power steering controller and actuator
Intermediate shaft
• The system will provide continuously variable steering ratio to reduced low speed steering workload.

• The system will provide continuously variable steering ratio at moderate speeds for a more direct steering feel.

• The system will provide continuously variable steering ratio at high speeds to reduce steering sensitivity.

• The system will provide the ability to counter-steer the driver's input to enhance vehicle stability.

• Transmit steering torque and react road feedback torque.

• The system will provide a fail-safe mode that reverts the steering system to the base steering ratio, under certain faults.

• The system dissipates excessive heat generated by the subsystem and be self protecting.

• The system will include features for quiet operation and to limit vibration generation.

• Absorb high frequency audible NVH from transmitting into the passenger compartment.

• Absorb low frequency chatter bump disturbances from transmitting to the steering wheel. This is not a primary function of AFS but a secondary.

• The AFS subsystem is designed to operate between the temperatures of -40 C to 75 C.

• Standard battery voltage is between 9-16 volts.

• This is on the GMLAN line and a dedicated chassis CAN line.

• Steering Wheel rotation is between 400-650 degrees.

• The AFS actuator is integral with the hydraulic steering rack or steering intermediate shaft. The AFS unit is used to add or subtract steering angle to the steering gear pinion. A position sensor is used to control the angle command from the controller. The angle change is accomplished through an electric motor and a reduction gear mechanism.

• The AFS controller takes vehicle and driver input signals (such as steering wheel position, vehicle speed, etc.) and converts them to an output current to the electric motor of the AFS actuator.

• The Active Front Steering Electrical subsystem and the Vehicle Stability Control Module (VSCM) participate in, and coordinate the control of Yaw Stability Control.

• Module will need a centering procedure when replaced.

Cadillacboy
12-17-07, 09:24 AM
What's said by BMW engineers you get more stable and sharper steering but I do prefer sticking to conventional system considering MB also tried to apply brake by wire system in their E Class .The result ? It was terrible and lotsa problems

Crown Vic Owner
12-17-07, 01:45 PM
weird, i was told that it was steer by wire, meaning completely done by wire.

I will never trust how well a owner know there car EVER again.

JTraik
12-17-07, 05:32 PM
You guys have no idea... try driving one of these at least 5 days a week doing at least 10 residential deliveries a day that required you to back into driveway... did I mention the power steering pump was toast in it???

http://www.delanos.com/images/01isuzubox1.gif

Its a small truck (comparatively)... I grew some forearms driving this POS.

dkozloski
12-17-07, 08:22 PM
You guys have no idea... try driving one of these at least 5 days a week doing at least 10 residential deliveries a day that required you to back into driveway... did I mention the power steering pump was toast in it???

http://www.delanos.com/images/01isuzubox1.gif

Its a small truck (comparatively)... I grew some forearms driving this POS.
Access on one of these is the best. It couldn't take more than an hour to fix anything wrong with the steering. After you dump the cab to the front it's all there in front of you. Your boss must be cheap beyond description.

JTraik
12-17-07, 11:05 PM
Access on one of these is the best. It couldn't take more than an hour to fix anything wrong with the steering. After you dump the cab to the front it's all there in front of you. Your boss must be cheap beyond description.

Hes cheap beyond 'beyond description'. I offer to fix the trucks all the time, he chooses to run them into the ground as was the case with this one. I was going down the expressway and the pinion gear in the diff. exploded simple fluid changed could have prevented that.

The cab flip was the only cool thing about these trucks... and their steering radius, other than that I hate them.

dkozloski
12-17-07, 11:16 PM
It seems to me that the running gear is all GM. The motor is a small block V8.

Red_October_7000
12-18-07, 01:33 AM
Those are indeed all GM. They also have the strangest control layout of anything I've ever driven. They do drive nicely, though... when the power steering is operational!