The Future of suspension

[Tim.Wright]

Regenerative dampers on a road car seems a bit of a waste of time to me. The damper power would be very low. Perhaps on a rally car, maybe it could help because there is more damping force and velocity (= power).

I'd also disagree with the statement that "most of what the suspension does is converted to heat". In fact, most of the suspension forces are sent through the spring for a period, then back to the ground. The next biggest proportion of suspension force is going through the links to accelerate the body. This leaves only a small proportion which is actually dissipated through the damper.

One of the main reasons trains use regenerative braking is move the energy away from the brakes and dispose of it without overheating the mechanical system. Electric 'dampers' as well as being theoretically programmable, could pipe waste energy away electrically. Using that waste energy to power other systems is a bonus rather than the primary aim.

Ok but the dampers on any tarmac racing car are more than capable enough of dissipating energy without overheating. I still struggle to see any scenario where a regenerative damper will actually give more laptime performance than it loses due to the extra weight.

Tomorrow, if I remember, I will calculate the power/energy dissipated by a damper across one lap.

[Lycoming]

This may be of interest.

http://www.mie.utoronto.ca/undergrad/th ... m%2036.pdf

To make any gains on a tarmac racer, a regenerative damper needs to be powerful enough to allow you to run a smaller, lighter battery. You don't make a net gain unless the reduction is greater than the weight of wiring, circuitry and magnets that the dampers add. worth noting: magnetic dampers are REALLY heavy!

For solar car people, who drive on the power of a hairdryer, you don't need much to be able to make a significant gain in that regard. For a racecar, energy is simply not as scarce, and therefore, not as valuable. Again, unlikely that you'd gain anything.

[g-force_addict]

You need to solve the 100 year+ dilemma on how to:
- Have the suspension move up/down with no camber change on bumps, braking and acceleration.
- Have the suspension change camber during turns for optimum cornering.
- For an added bonus you can also counteract body roll.

[Tim.Wright]

Its been done.

http://www.walker-partnership.com/

Unfortunately, there is a little more to a suspension system than getting the camber angles right. Also, roll in itself its not actually a bad thing. Its actually needed to control the roll stiffness distribution.

[g-force_addict]

Its been done.

http://www.walker-partnership.com/

Unfortunately, there is a little more to a suspension system than getting the camber angles right. Also, roll in itself its not actually a bad thing. Its actually needed to control the roll stiffness distribution.

Not solved at all.

This has horrible bump camber change for BOTH wheels.
i.e. When one wheel hits a bump, camber changes for both wheels. Even more than a solid axle.

[Tim.Wright]

Well first I'd ask you to define "horrible". Secondly, camber change from single wheel bump is not as important as camber control during roll and pitch. So if you have some increase in bump camber but a large reduction in roll and pitch camber, then you are still coming out on top.

The fact is, unless you have a completely active suspension, you every parameter you try to control will be a compromise with something else.

Anyway, what I was getting at in my previous post is that the angles of the wheels are only half of the problem a suspension is trying to solve. The control of the forces is the other half. I haven't done any analysis on this suspension but I imagine it has a very non-conventional roll centre placement.

[CBeck113]

While that's not entirely motorsport related, as someone who drives upon a moon surface-like road (Sofia), I have to change suspension parts frequently, so I'd vote for easier to manufacture parts, which are supposedly cheaper and/or more solid.
On the other hand, suspension modes have to be user-selectable, most of all which I appreciate are BMWs recent incarnations and GTR's damptronic shock-absorbers.

Rules are generally defining what the design trend could be. Have you checked our FRIC discussion topic? Some say it's the must-have gizmo for 2013 and onward.

Then never buy an Opel! I've changed just about everything on the front suspension and drive shafts, and live in Germany . I will be changing the coupling rods for the third time (180k km) this weekend.
The future would be active, the the rules will not allow it sadly.

[KeithYoung]

I personally think Active Suspension is the way to improve suspension. Computers are cheap, powerful, and small enough to handle this stuff fairly easily.

[Tim.Wright]

The decision of active or not depends on the application. If it were legalised in motorsport I think it would be very useful mainly for aero reasons and mainly because the minimum weight rules are sufficiently high that there would be no weight penalty for such a system.

Outside of motorsport I'm more skeptical. I think active ride has the potential to greatly improve ride comfort but in terms of performance, I find it difficult to see a net increase of performance after the extra mass is taken into account.

In terms of stability, safety and driver feedback I think there would be significant gains. This is what the OEMs are more interested in anyway.

[DaveW]

If it were legalised in motorsport I think it would be very useful mainly for aero reasons.

The would certainly be the conventional wisdom. However, since mechanical performance tends to be heavily comprised in favour of aero in current passive suspensions, I would expect that the freedom offered by active suspension would have more impact on mechanical performance (especially tyre life).

... I think active ride has the potential to greatly improve ride comfort...

I'm not sure I agree with the statement either, Tim. It is true that active suspension relaxes the ride/handling compromise, but absolute ride comfort tends to be affected more by vehicle properties than suspension properties. Newton's second law still applies.

...In terms of stability, safety and driver feedback I think there would be significant gains.

True, although "safety" and "driver feedback" are both difficult to quantify.

[Tim.Wright]

I agree with what you said about the comfort. What I meant is that with an active ride you can setup the suspension more focussed for comfort (i.e. setup to absorb high frequency inputs) and use the active ride to keep the body movements under control (low frequency).

...In terms of stability, safety and driver feedback I think there would be significant gains.

True, although "safety" and "driver feedback" are both difficult to quantify.

Difficult to quantify on a test rig maybe but all the OEM's have got their test drivers who will tell you immediately if the feedback is better or worse. Sure its a bit subjective but all the OEM's have a reasonably well defined "DNA" that defines how their cars drive. The addition of an active system I believe could work in this "tactile feedback" range of yawrate and lateral acceleration to make small changes that a test driver detects but handling measurements usually miss.

[DaveW]

...Sure its a bit subjective but all the OEM's have a reasonably well defined "DNA" that defines how their cars drive.

Very subjective... Otherwise, all cars would "feel" the same....

The addition of an active system I believe could work in this "tactile feedback" range of yawrate and lateral acceleration to make small changes that a test driver detects but handling measurements usually miss.

You may have omitted steering torque and, perhaps, vehicle sideslip from your list....

[Richard]

If the 'whole' suspension was elecrtomagnetic without mechanical springs, then recovering the energy would be useful.
Oh sorry ignore that, its of topic.

Its on-topic over here ... http://www.f1technical.net/forum/viewto ... =6&t=15063