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New Car Can Lean Into Curves, Literally
cartechboy (2660665) writes "You know how motorcycle riders lean into the corners, sometimes even touching their knee to the ground? Mercedes-Benz has developed new technology that replicates that sensation by leaning the car into bends. It's called Dynamic Curve and it's part of the Active Body control suspension system on the new 2015 Mercedes-Benz S-Class Coupe. In turns, special plunger cylinders raise the suspension struts and lower the opposite side, depending on the direction of the bend. This has the result of tilting the car body slightly towards the inside of the corner, countering centrifugal cornering forces. Mercedes says it's not design for increasing cornering speeds, but increasing pleasure for the driver and passengers."
As long as internal car data bus allows me to tie the sound system to the suspension system so I can bounce with the music down the road.
Except the current suspension compresses on the outside of the curve. This system sounds like it compresses on the inside of the curve, redirecting the g-forces into the occupants' buttocks and not the sides.
Think. Cars naturally lean THE WRONG WAY on curves. They tilt over toward the outside. This magnifies the centrifugal force you feel by adding a gravity component to it.
We are talking about suspensions that lean THE RIGHT WAY on curves. They tilt toward the inside, like a banking airplane. This reduces the centrifugal force you feel by subtracting a gravity component from it.centrifugal
This adaptive suspension technology can be valuable for addressing poor roadway design, such as opposite-camber banking (yes, such things exist and can be very dangerous in poor weather). One of the most egregious examples of opposite-camber banking occurs in Canada between Vancouver and Burnaby, BC on Boundary Drive on which vehicles travel steeply downhill, typically in rain, and are presented with an opposite-camber dogleg turn about half the way down. So, while everyone is riding their brakes their vehicle suddenly gets crossed up. Since it is noticeably uncomfortable in a low-slung sports car, it is more than an annoyance on buses and in large trucks. Redesigning/repairing those poor roadways can take years, so any step by vehicle makers to have this kind of adaptable suspension is worthwile.
I deny that I have not avoided attaining the opposite of that which I do not want.
Drivers depend on feedback from the car to help them make necessary adjustments.
If a curve isn't banked enough, the car shouldn't fool the driver into thinking that it is banked enough.
That feeling one gets when the car leans towards the outside of the curve is telling the driver to slow down!
There is no such thing as centrifugal force... when you talk like that you basically show why dumbasses shouldn't be involved in car design.
Stock XKCD counterpoint: Centrifugal Force
A couple of others have mentioned the ~2007 work that Bose did in active suspension, but nothing really clarifies the idea like pictures or video:
http://www.youtube.com/watch?v=eSi6J-QK1lw
Leaning into a curve is one thing, but At 1:40 the car jumps a curb-size obstable. Nice.
I'm not sure it's worth the engineering complexity versus standard sway bars (for a typical diver),
http://www.youtube.com/watch?v=_liGnV3PTiQ
but Bose's system (and Mercedes') sure as hell is cool.
And while we're on the topic of making unreasonably large cars more agile than they ought to be, I'm still pretty happy with Volvo's 4C system and oversized sway bars on a 7yo S80 V8 -- switching to "advanced" it behaves like a fat WRX or that pudgy football player you didn't think could move that fast, and in "comfort" mode it hunches down *evenly* about 6-8cm in hard curves... all with just plain old leverage, a few poly bushings, and electromagnets around the ferro-oil filled shocks. Simple is good.
I think not...(*poof*)
The car going around the curve can be seen to be in a rotating reference frame from the point of view of an observer in the car with the center of rotation at the point inside the curve which the car is maintaining a constant distance from. And the car itself is rotating in inertial space by the fact that the direction it is pointing is changing going through the curve (unless it is understeering very badly).
ABS generally pumps the brakes at 25hz or higher, about 25 times faster than a human, regardless of how bad ass you THINK you are.
The wheels do, in fact skid a little bit. Wheel skid is how the system knows to pump the brakes. ABS brakes will still live skid marks. The wheels suddenly start having large differences in rotational speeds under heavy breaking and between that and accelerometer data the computer knows you've got one or more tires losing traction.
You didn't slide through an intersection because of ABS, you slide through it because you were going to fast for conditions.
Science ... Using professional race car drivers says you are flat out wrong. You can not brake better and maintain control better than a functional modern ABS system. The fact that you are so arrogant and stupid to think you can is reason enough to revoke your license.
They still offer cars without ABS because it's cheaper, and some people want cheaper
Your an idiot. Stay off the road, please, before you kill someone.
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Actually, the force that is pushing you against the seat is centripetal force, not centrifugal force.
Depends on your reference frame.
The only real force is the angular one
Centrifugal force is quite real. So is the Coriolis force and the Euler force . All three occur when the reference frame used to describe the force accelerates relative to another reference frame and in fact you cannot accurately solve many classical mechanics problems without them. For example the surface of the Earth is a rotating reference frame. Don't confuse the meaning of the term "fictitious force" to mean that it doesn't exist. A fictitious force is one that simple doesn't exist in an inertial reference frame. There still are non-inertial reference frames.
ABS is dangerous to people who learned to drive without it.
Only if they are not competent drivers to begin with. ABS was not on the vast majority of cars when I learned to drive and we seem to have somehow survived the transition. ABS demonstrably makes drivers safer and there is plenty of data to prove it.
The normal technique of locking and releasing the brakes by pumping the pedal doesn't work, because the brakes never lock in the first place, so all you end up doing is repeatedly letting go of the brake for no reason.
Manual pump braking works exactly the same way with or without ABS. ABS does exactly the same thing as manual pump braking but ABS does the braking and releasing but much faster than any human could possible do it and therefore it works better.
The only time I have ever slid though a stop sign in the snow was in an ABS vehicle.
Oh, well, one anecdote should convince us all... [/sarcasm] You can still slide in an ABS equipped vehicle if the road is sufficiently slippery. If the surface is truly close to frictionless it doesn't matter what kind of brake system you use. You are along for the ride. For example my driveway is fairly steep and after an ice storm you are going to slide down a portion of it. It does not matter what you do with the brakes because there is basically no friction between you and the road. You didn't slide through the intersection because of ABS. You slid because you were going too fast.
Think. Cars naturally lean THE WRONG WAY on curves. They tilt over toward the outside.
There's no "right way" or "wrong way" for a car to lean on a level surface with all four wheels on the ground. The motorcycle metaphor doesn't work well here because part of turning a two-wheeler involves moving the center of mass off the centerline and letting gravity pull you through the turn. To paraphrase Douglas Adams, turning a two-wheeler involves throwing yourself at the ground and missing.
This magnifies the centrifugal force you feel by adding a gravity component to it.
On the contrary: being thrown towards the outside of the turn means the turn radius increases, which results in a decrease in centrifugal force.
They tilt toward the inside, like a banking airplane.
Another poor comparison. Airplanes roll while turning because their wings are their largest working surface areas and need to be tilted off of horizontal to get the lift vector pointing "that way." The comparison here would be in banking the road surface itself (the working surface for a ground vehicle) rather than any shifting done by the suspension on a level road surface.