Some cars have an active suspension: that is, instead of just having springs and dashpots, they have motors which actively work to smooth out the ride. These motors are driven by a system which senses the motion of the car/tires/etc and tries to cancel them.

Presumably, however, even this can't smooth out all bumps. (I'm not actually sure whether I've ridden in a car with an active suspension.) Most driver-hours are spent driving a few routes over and over again --- eg, a daily commute. So, if the active suspension were coupled with a GPS receiver and a memory, it could remember where all the bumps are on your route and exactly how high they are, enabling it to smooth them out perfectly. (GPS probably isn't of fine enough resolution, so throw in a hidden-Markov-model, Kalman filter, or the like to allow the suspension to use the remembered & perceived road surface to fine-tune its notion of its location.)

Advantage: a nice smooth ride, and another excuse to use GPS and HMMs.

Disadvantages: Well, if a pothole were repaired, your car wouldn't learn of this until you had driven over it a few times. So you'd have a faint "afterimage" of the pothole for a few days.

Also, the rich would all have predictive suspensions, and would not feel flaws in the road surface and would see no need to have the government spend money repairing the roads. The roads would deteriorate into impassable ridges and ruts, and civilization would collapse, and all die. O, the embarrassment.
-- wiml, Dec 24 2001

The six-wheeled car http://www.halfbake...20six-wheeled_20car
tangentially related... [hippo, Oct 04 2004, last modified Oct 05 2004]

<rant>Shame this wasn't around 2 days ago in the form of compensating for lack of 4-point contact with road surface - My Fiancees Nephew, His Girlfriend and their 6 Month Old Baby were in a Ford Bronco travelling to spend Christmas with the Grandmother and Us. The Passenger Side Rear Wheel came off the hub completely and as a result the Bronco rolled 4 times. The Baby was strapped in and received very minor abrasions. The Mother of the child has a broken thumb, a broken angle and is bruised over half her body. The Father - I will see in 18 hours - he got the worst of it. He had bought the now demolished vehicle 2 weeks ago, and had new tires put on just 1 week prior to accident. Great Job Installers. Hopefully next time, they'll remember to tighten all 4 of the wheels.</rant>
-- thumbwax, Dec 25 2001


Just strap lasers or radars to the front bumpers and measure the distance to the ground every few milliseconds. Use a computer to move the wheels up and down with the road to maintain a constant average altitude AGL. This eliminate the (re)learning curve, doesn't rely on predictive data and doesn't rely on an outside system to function.

One downside would be that fender benders would be astronomically expensive.

[thumbwax] I hope everything works out for your fiancees nephew. I'm glad his girlfriend and baby are all right.
-- phoenix, Dec 25 2001


Every time UnaBubba tells that story, it gets stuff added to it.
Sorry the Earth lost such a character, let alone the fact he was kin, UB.
Broken Tailbone on Nephew - They had gotten married 2 days prior, and Bronco was uninsured. I got to play psychochiatneuroliagecounselmediatravelagentyer for a few days - what a Christmas for these folks.
-- thumbwax, Dec 26 2001


Thumberg, Goldwax, Thumbwaxstein and Waxociates, LLC

The Thumphew is retaining services of a highly profitable and contagious litiganthill. It is expected to be just plain lawful.

Wax N. Stein
-- thumbwax, Dec 27 2001


Have open content sharing of topographic data between cars. This way with a few thousand such cars in regular use it should be possible to make a very detailed and up-to-date picture of road surfaces for miles around. Perhaps the data exchanges could take place in parking lots.
-- LoriZ, Dec 28 2001


True, this would work well if integrated with the FRCs.

One problem with the shared database idea: malicious users (eg hackers). I could sit somewhere with a fake transmitter, repeatedly broadcasting news of a nonexistent pothole, and chuckling as everyone's suspensions go crazy anticipating it.
-- wiml, Dec 28 2001


Public key crypto could prevent that. Send a signature along with the transmitted data, and if it doesn't match the signature of the appropriate government department (stored within the receiving car somewhere), ignore it.
-- cp, Dec 29 2001


Nah, it's an idea by [cryo].
-- cp, Dec 29 2001


[cp]: thought of that. PK crypto won't help if the idea is that cars can share road-surface information. All I have to do is impersonate a car (or a series of cars) going over the nonexistent pothole and "warning" others about it. Yes, yes, you can get all fancy and add tamper-resistant modules, traffic analysis, reputation systems, trusted third parties, etc., but then it's no fun any more. I'll just take my plain ol' non-distributed predictive suspension.
-- wiml, Dec 30 2001


(Carrying on from UB)

Yes man: Sir, the car ahead of us is spewing out paragraphs on end about potholes, and we can't work out who it is.

Boss: Does it sound like a harebrained scheme for solving suspension problems for once and for all? Lots of pseudo-science and a disclaimer that it was written 15 years ago, but would still work if only he can get his car to defy gravity?

Yes man: <consults printout> Er, yes, how did you know, sir?

Boss: It's Vernon. He must have got that grant from MSRC after all.

------[return to normality]------

[wiml] Yes, that's true. I think it would work if the suspension information wasn't transmitted from car to car, but instead from some device on the side of the road; that wouldn't be as nifty as having cars cooperate, though.
-- cp, Dec 30 2001


Cadillac already has a similar suspension but to replace each strut costs around 700.00. Most owners swap in a custom passive strut system.

Ty
-- speedyguy, Aug 05 2003


Actually F1 used laser ride height and suspension control over 11 years ago. In addition, Nissan's 300ZX from almost 20 years ago had laser controlled suspension in a prototype.
-- amuron2, Dec 21 2003


loryz wrote that anno before the "Ways app" craze.

[phoenix] basically wrote an idea that I had been contemplating for the longest time.
-- pashute, Feb 18 2014



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