Tony Posted December 16, 2008 Report Share Posted December 16, 2008 Active steering employs a combination of a conventional "Rack and Pinion" steering system with a planetary gear system. The planetary gear system is actuated via a 3-phase DC motor which is controlled by an electronic control module. The Active Steering system allows a steering ratio which is fully variable based on road speed and environmental conditions such as yaw and lateral acceleration etc. In contrast to a variable rack and pinion, which is purely mechanical, the ASS system is capable of manipulating the steering ratio from a more direct ratio (10:1) to a less direct ratio (20:1) Related topics Active centre weighting Steer by wire ECU programmable steering preferences Quote Link to comment Share on other sites More sharing options...
dazz33 Posted December 16, 2008 Report Share Posted December 16, 2008 what cars have this on then Tony..? looks like a very complex bit of kit....damn expensive when it goes pear shaped... So would this have any affect when it comes to setting up a car..? or is it just the same as standard PAS... Quote Link to comment Share on other sites More sharing options...
Tony Posted December 16, 2008 Author Report Share Posted December 16, 2008 Most modern cars employ this system and as usual with new concepts it's not without it's flawes. Common complaints are "a dead feel" to the steering and an off-set centre steering position. Both the dead feel and the centre position can be dealt with via a ECU plug in Quote Link to comment Share on other sites More sharing options...
Rich Posted December 16, 2008 Report Share Posted December 16, 2008 That looks complicated...also with these advances in technology is it making it more difficult for the home mechanic to work on their car? Quote Link to comment Share on other sites More sharing options...
CIH Posted December 16, 2008 Report Share Posted December 16, 2008 Our service dudes recently got the new "plug in and play" tech kit and there's a scetion on Geometry. Some really interesting stuff. For example, on newer Renaults, chaning wheel sizes requires the ECU be set into a kind of learning mode so it can adapt and ensure ABS etc works as intended. Quote Link to comment Share on other sites More sharing options...
Tony Posted December 16, 2008 Author Report Share Posted December 16, 2008 If it's an ECU problem even i cannot work on the car..... collectively the software would cost 100k, so all i can do is confirm the need, not the solution. Quote Link to comment Share on other sites More sharing options...
CIH Posted December 16, 2008 Report Share Posted December 16, 2008 Apparantly some VAG cars require the ECU be told Geometry is to be altered. They have a dash warning light for it, though I'm dubious as to how it would work without misinforming the customer. Quote Link to comment Share on other sites More sharing options...
Rich Posted December 16, 2008 Report Share Posted December 16, 2008 I'm not convinced it's a good idea to have (nearly) everything on a car controlled by the ECU...just going to bring more hassle with it or even make the car dangerous in some cases. Thinking back to that mini with the damaged run flat tyre that wasn't detected by the car due to a fault with the sensors. Quote Link to comment Share on other sites More sharing options...
CIH Posted December 16, 2008 Report Share Posted December 16, 2008 y'know the electric handbrake on Renaults has an ecu and needs the 100k gear to windback the actuator before you manually windback the piston. Can you imagine trying to fix a dodgy handbrake on such a car in 10/15yrs time ? Quote Link to comment Share on other sites More sharing options...
Mark H. Posted December 17, 2008 Report Share Posted December 17, 2008 This paves the way for steer by wire somewhat which has kind of failed to stick before, gives them lots of cars to test longevity of the electric parts and systems in steering. Adds in obsolescence instead of having a 10 yr old car you'll need a newer one as it will be too expensive for you to fix all the electronics. Its about as good as my last cars having a fuel pump ecu, (£130 to switch 9-12v to the fuel pump) surely the engine ecu could just switch the 2 based on fuelling eg up voltage after idling. Quote Link to comment Share on other sites More sharing options...
Sagitar Posted December 17, 2008 Report Share Posted December 17, 2008 This paves the way for steer by wire somewhat which has kind of failed to stick before, gives them lots of cars to test longevity of the electric parts and systems in steering. Adds in obsolescence instead of having a 10 yr old car you'll need a newer one as it will be too expensive for you to fix all the electronics. Its about as good as my last cars having a fuel pump ecu, (£130 to switch 9-12v to the fuel pump) surely the engine ecu could just switch the 2 based on fuelling eg up voltage after idling. The last time I read about active steering was in a technical paper by (I think) an engineer from one of the F1 Teams. I shall not remember the detail accurately but the key issue as he described it and I recall it, is to provide a range of sensors that measure steering wheel position and various other positions and rates of movement related to the road wheels and to use these to sense the requirement for steering corrections much more quickly that a human driver can when the vehicle is at the limit of adhesion and is, in effect, an unstable system. Having sensed the requirements, the system then makes the necessary corrections, again, at a frequency much higher than a human driver could. To allow the system to make corrections requires a variable relationship between the position of the steering wheel and the position of the road wheels. The arrangements that allow this variation also enable speed related steering ratios, easy parking etc but I read these as being additional benefits rather than the prime purpose. I should also say that the system is integrated with other stability systems which we would know as abs, traction control etc. The paper also described the fail-safe condition that applies if things go wrong and as I recall it, it is essentially an arrangement for locking up the variable arrangments such that the normal, fixed ratio, rack and pinion system operates and control returns to the driver alone. I am sympathetic to the views expressed by others about the need for this kind of sophistication on normal road-going passenger vehicles. I think it may indeed appear to be a step too far, but we have said that so many times in the past of functions that we now take as normal. The question of servicing older vehicles is an interesting one, but not in my experience likely to influence manufacturers. It is not a new phenomenon. Back in the early 60's I was involved in a conversation with Sir William Lyons which included me making some remark about how Jaguar could make it easier for impecunious people like me to service a second-hand Jag. His response, abbreviated somewhat, was that his company didn't make second-hand cars. Quote Link to comment Share on other sites More sharing options...
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