15 replies to this topic

[glorius&victorius]

The best known active suspension F1 car was the FW-14B which took Mansell to the WDC.

What is known of the Lotus (1987) which Senna drove? Was that the first active suspension car?
What were the conceptual technical differences with the FW-14B? How did Lotus' active suspension work, and how was it different from the FW-14B


Thanks!

[ZoRG]

I might be wrong, but I think the way the lotus active suspension works is by having sensors on all 4 wheels, they take measurements 100-1000 rimes per second and can then "feel" when there is a bump or when the car is cornering, if it feels a bump it will soften the shock and allow the car to "ride" it smoothly, when it senses cornering it will stiffen up the side under pressure.

Hope this helps.

Cheers

[schuy]

Originally posted by ZoRG
and can then "feel" when there is a bump or when the car is cornering, if it feels a bump it will soften the shock and allow the car to "ride" it smoothly, when it senses cornering it will stiffen up the side under pressure.

Isn't that the meaning of active suspension?

Whilst normal suspension will work on it's own, active suspension will communicate with it's different components and adjust it's 'specifications'.
Am I wrong?

Liran.

[ZoRG]

I think so too, I read an article on the Lotus suspension a long time ago, thats sort of what I remember from it.

[Greg Locock]

That is the basic idea behind active suspensions, the idea being that the vertical load is redistributed among the tyres continually so that the body has a somewhat smooth path.

In practice, to make setting the car up more intuitive, Lotus used a complete matrix of wheel to wheel couplings - in essence you could dial in an anti- bar between say the front left and the rear right wheel, if you wanted. This made tuning the car more like tuning a conventional car, rather than an exercise in control systems theory. I'm not sure when this was introduced into the code, but it was always there from 1988, when I first got peripherally involved.

I am 99% sure they would have included a feed from the steering wheel as well, so you can dial in changes to the car ahead of the roll sensors etc picking up the responses of the car, which is the main limitation with the performance of current active systems.

[desmo]

Active suspension first appeared, I believe in 1983 concurrently on the Lotus T92 and in a semi-active form based on a concept for Citroen road cars in the Ligier JS19.

A good brief account of it's genesis at Lotus is included in Peter Wright's book, "Formula One Technology" in Appendices A & C.

[gug]

so how did they make the suspension harder or softer? i can see how dampers could easily be changed, but how do you change spring rates on the fly? or was it just damper changes?
does anyone know a measure of how much faster it made the lotus? or any other car with active suspension for that matter?

[david_martin]

The FW-14B was by no means Williams' first active suspension car either. Prior to Adrian Newey arriving at Williams, Frank Dearnie and Patrick Head had done an active version of the 1988 FW-12. Mansell was famously scathing about the active ride on that car, it was one of the reasons Mansell cited for jumping ship to Ferrari.

[Greg Locock]

In the original Lotus system there were no conventional springs or shocks, all they had were hydraulic rams. These were instrumented and driven by servo valves. By adjusting the oil flow to and from them they would replicate the effect of springs and shock absorbers. This is called a full authority active system, in that all the forces are controlled actively.

I have to say that whoever decided to put the struts in parallel with conventional coil springs had their head screwed on. The slight loss of theoretical beauty is more than made up for in practice.

[OO7]

Are there any figures avaliable estimating bhp consumption for the last generation of actively suspended cars such as the FW-15C?.

Thanks
Obi

[mera308gtb]

Originally posted by david_martin
The FW-14B was by no means Williams' first active suspension car either. Prior to Adrian Newey arriving at Williams, Frank Dearnie and Patrick Head had done an active version of the 1988 FW-12. Mansell was famously scathing about the active ride on that car, it was one of the reasons Mansell cited for jumping ship to Ferrari.

At the British GP that year Williams tried a convetional suspension which seemed to work much better. After both drivers declared a marked improvement, the Williams team were sent scrambling all of Saturday night to get springs in order to build up both race cars. I think they had some guy in a parts shop somewhere in England stay open late and someone went to pick them up. As it turned out, Mansell drove brilliantly to finish second to Senna.

BTW, that year Wiliams were forced to call their system a "reactive" suspension as Lotus claimed ownership of the "active" suspension moniker. I don't know if there were actually any legal goings on, but by 1992 Williams had their "active" suspension. Anyone remember the whole story?

[stuartbrs]

Williams actually ran an active FW11 in 1987 which they bought to races that year. I`m fairly certain that Piquet raced it on occasion but not Mansell ( although he did run it in practice ).

The lotus and Williams systems were completely different. The Lotus unit being very heavy and much more complex than what Williams used. Senna won with the active Lotus in `87 and both his victories that year were on bumby street circuits that suited active ride.

This thread has some good information on Lotus active suspension.

http://forums.atlasf...ight=team lotus

[Sir Winston]

There is a good article about this at
http://www.gglotus.o...activesuspn.htm

[Greg Locock]

The big killer for active suspension was the absence of look-ahead (in much the same way ABS etc would be vastly improved if we actually knew what the friction coefficient was). The first thing you knew about a bump was when the front wheel loads increased.

Since one of the intelligent cruise control systems is likely to use vision or millimetric radar it seems likely to me that a cheap look ahead sensor for bumps could be developed, in which case you could develop a true magic carpet ride with no (well, much reduced) handling compromise.

[Supercar]

Originally posted by Greg Locock
...it seems likely to me that a cheap look ahead sensor for bumps could be developed, in which case you could develop a true magic carpet ride with no (well, much reduced) handling compromise.

Wow, that's an idea for high-end production cars! Imagine a car extending a wheel if a dip in the road is observed, or lifting a wheel for bumps and potholes! No more bent 22" rims! I bet insurance companies will love it.

Philip

[OO7]

Bringing the topic of power consumption up again: Would it be possible to programme the active suspension, to 'lock' the cars attitude above a specific speed threshold, thus allowing the ativetransitioning into some sort of power saving mode?.

Also if a car is equipped with active suspension, does this mean the engineers/mechanics no longer need to concern themselves with damper characteristics/setting?. If so how do they alter the region of the cars handling, e.g oversteer and understeer at the different phases of a corner, that were previously managed by springs and dampers in a passive system?.

Thanks
Obi