Active Steering

[Ahbengdriver]

How many of you guys here find active steering good or just waste of money.

Is it really as good as claimed or in fact impeding the sheer driving pleasure.

[TheNew7]

I really love it.... you park more often than you drive up to 200kmh..... so yeah, for me, its great.....

[elmariachi]

Originally Posted by Ahbengdriver

How many of you guys here find active steering good or just waste of money.

Is it really as good as claimed or in fact impeding the sheer driving pleasure.

As most Ah Bengs like to drift in their Cheebic, i guess you will be drifting too in your upper class bengmobile. All u need to drift is 10secs before the fuse of your active steering burns off. I wudnt take the risk if you drive like that. FOr me, Active Steering is a no-no. To some, its godsend. SO you really gotta evaluate your driving patterns.

[TripleM]

If it's an option, then not for me
I dont mind electric powersteering but not active steering

[elmariachi]

Originally Posted by TripleM

If it's an option, then not for me
I dont mind electric powersteering but not active steering

Triple M,

You mean like the servo-electric steeing=electric steering like your previous Z4?
I know active steering is way different.

[elmariachi]

Difference between Servotronic Steering and Active Steering



On the road to the totally-active by-wire wire automobile, the deepest pothole engineers face is steering systems. Safety regulators, customers, and liability attorneys have no problem with technology aimed at reduced parking drudgery and there is sincere appreciation for the great strides achieved with handling. But accepting wires and motors as the logical replacement for mechanical steering linkage demands a leap of faith lying somewhere between fuel cells and the tooth fairy.
This is not to suggest that the quest for smarter chassis systems is hopeless. To the contrary, Bosch and ZF contend that by-wire steering is a viable near-term goal. Towards that end, they formed a 50:50 joint venture four years ago to pursue electronic steering systems. Notes Colin Carter, executive vice president responsible for sales at ZF Lenksysteme GmbH (the Bosch-ZF consortium), "The auto industry is interested in more intelligent systems capable of interacting with other systems. But standard hydraulically assisted power steering lacks that capability. The solution is to find some way to electrify these systems."
Bosch began investigating electron steering more than a decade ago. ZF Friedrichshafen AG's gear cutting an mechanical-systems expertise made it the ideal partner. The first product of the 1999 Bosch-ZF union is Servolectric steering systems (with power assist supplied electrical instead of hydraulically) already available on European VW Golfs. Servolectric steering is also installed on BMW Z4, Audi A3 and VW Touran. The second step forward is an interesting blend of current and advanced technology called Active Steering. Without disconnecting the conventional mechanical linkage to the front wheels, equipment is added that facilitates a degree of computer control over the car's direction of travel. This hybrid approach narrows the chasm between today's largely passive steering systems and the fully active equipment that will inevitably guide cars of the future. (General Motors recently acknowledged it too has a motorized hybrid steering system under development.)
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In the form adopted by BMW for optional use on its 2004 5-series sedans, Active Steering is an add-on module mounted to the pinion shaft between a conventional ZF Servetronic 2 torque-sensing power-assist control valve and the rack housing. Housed inside the module's compact aluminum casting, there's a compound planetary gear set. An electric motor that drives the planetary gear set's carrier on demand and an electromagnetic locking device that disables the active side of the steering system are externally attached.
A separate electronic control unit (ECU) gathers operating information from various car systems (steering wheel angle, pinion angle, road speed and individual wheel speeds) before dispatching electrical commands to both the hydraulic-assist control valve and to the Active Steering system's electric motor. A conventional engine-driven pump supplies hydraulic pressure to the power-assist cylinder contained within the rack housing.
The aforementioned planetary gear train seamlessly blends mechanical and electrical steering commands. At its upper end, a sun gear is rotated by steering wheel motion. That gear meshes with three planet gears which in turn drive a second sun gear attached to the pinion shaft. As long as the planetary set's carrier remains fixed, steering shaft input rotation is faithfully conveyed to the pinion shaft without alteration. According to Bosch-ZF engineers, the added friction from these eight meshed gears is inconsequential to the driver because it occurs downstream of the steering system's hydraulic control valve.
The fun begins when the ECU disengages the electromagnetic locking unit (which assures normal mechanical steering in the event of any electronic systems failure) and tells the electric motor to spin the planetary gear set's carrier. Active Steering is able to speed up or slow down the steering ratio independent of steering effort (which is coordinated and controlled by the same ECU through the Servotronic power assist control valve).
Ultimately the mechanical side of today's Active System will wither and vanish like frog gills and tails on the evolutionary path to full steer-by-wire directional control. But today there are three key advantages available to enhance a BMW 5-series owner's safety and driving pleasure. The first is a steering ratio approximately 30-percent quicker than normal at low to medium road speeds, Suddenly a large, long-wheelbase sedan is able to mimic a subcompact's agile moves. The second benefit is that at highway cruising speeds the steering ratio is 25-30-percent slower than normal in the interests of placid straight-line cruising. The third pay-off is much quicker reactions when corrections are necessary to stabilize a car on the verge of oversteer (rear tires sliding wide). According to ZF Lenksysteme Engineer Peter Brenner, Active Steering corrections aimed at thwarting a skid are enabled approximately four times faster than the corrections possible with brake-based stability systems such as ESP.

[Rastaman]

Originally Posted by elmariachi

All u need to drift is 10secs before the fuse of your active steering burns off.

I was told by its 8 sec by pml staff. Anyway i juz prefer the normal power steering !

[elmariachi]

Originally Posted by Rastaman

I was told by its 8 sec by pml staff. Anyway i juz prefer the normal power steering !

Now isnt that worse. Like geylang 40mins then sudddenly market drop to 20mins?!??
Yeah man..normal still da bestest!!

[centurion]

I just found it a little dangerous. Just my take on what active steering is first - the car will use the DSC+T sensors and computer to control a planetary gearset, much like an auto transmission, which changes the mechanical ratios of the steering, making the effect of each degree of movement of the steering to have MORE or LESS relative effect on the wheels turning, depending on the computer's analysis of the sensor data.

During the launch of the 5-series after makan I took the wheel of a 530.

First off, it already felt weird - stationary the steering was very very fast. Cool I drove off. All the time I was conscious of the fact that this steering changes ratio.

On the PIE to Jurong, I was in the slowest lane at 130kmh plus when told to turn off Clementi (the unique turn on the right). So I braked substantially and turned right to change lane to the rightmost lane, and the car destabilized. Because at high speed, the planetary gear made the effect of my turn to be very little, but then when I braked, the effect of my turn increased. An IDIOT I am, I remembered how little the effect of my turn when I was at 130kmh, so I used more turn when I braked, and the steering rack responded MORE than I was at 130kmh.

Anyway, that was the `launch' since then I have tried the 5-series quite OK (not sure whether they have AS or not).

By the way, the new caymans and boxster 987 series all have variable steering, the new S2000 also have. NOBODY is complaining. And for BMW's AS, there're LOTS of rave reviews.

[ryan]

Servotronic steering really tends to suck ass on my current ride. There is this terrible chunky dead feel on extremely noticeable on the expressways.

Apparently the sports button gets rid of this feel by being more "responsive" (!?!?). Nonetheless, back to the topic, i would go with traditional steering. Never tried A.S so am not sure whether it would be a predictable steering feel / behavior when you have purist "drivers" at the wheel.