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New Car Can Lean Into Curves, Literally 243

Posted by samzenpus
from the lean-into-it dept.
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."
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New Car Can Lean Into Curves, Literally

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  • by Nkwe (604125) on Sunday June 08, 2014 @01:59PM (#47190889)
    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.
    • by Tablizer (95088)

      Don't worry, if you don't figure it out, hackers will.

  • Suspension on cars do this automatically, already. That's a big part of the reason we have suspensions on cars. I can't imagine there's that much of a benefit to counter the extra weight and complexity of the system.
    • Re:Gimmick (Score:4, Informative)

      by Anonymous Coward on Sunday June 08, 2014 @02:04PM (#47190917)

      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.

      • Re: (Score:2, Informative)

        by Anonymous Coward

        Except sway bars counter that effect by lifting the inside wheel. Stiffer/bigger sway bar, you can get it to do what mercedes is doing with a lot more work. Lets not even get into torsion bar systems.

        • Re: (Score:2, Informative)

          by Anonymous Coward

          A sway bar, no matter how stiff, can only reduce roll, not counteract it completely. What Mercedes is doing goes much further than that: it actually makes the car lean inward, resulting in a more comfortable ride.

        • by Duhavid (677874)

          Sway bars counter but do not entirely eliminate this effect. They for certain do *not* raise the other side of the car.
          So, no, you dont get what mercedes is doing.

    • by Drew M. (5831)

      Umm, they are talking about leaning the car inward, not leaning outward. Go take a drive right now and see what happens when you corner due to physics.

      • Go take a drive right now and see what happens when you corner due to physics.

        It kind of reminded me of my physics class in high school, where I goofed off and got sent to the corner.

    • Re:Gimmick (Score:5, Insightful)

      by fnj (64210) on Sunday June 08, 2014 @02:07PM (#47190937)

      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

      • by thrich81 (1357561)

        Check the direction and magnitude of those force vectors there -- whether the car leans inward of outward in the curve the resultant force vector is the same -- the sum of the gravity and the centrifugal force at (about) right angles to the gravity; the direction of this resultant sum as felt in the car is somewhere between down and toward the outside of the curve. The difference is that if the car is leaning inward then your body is more aligned with the resultant and it feels more comfortable (just as in

      • Re:Gimmick (Score:5, Informative)

        by Guppy06 (410832) on Sunday June 08, 2014 @10:39PM (#47192829)

        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.

    • by Freshly Exhumed (105597) on Sunday June 08, 2014 @02:12PM (#47190961) Homepage

      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.

    • The main job of the suspension system to make sure the tires stay in contact with the road. Because of the springs, the system will try to lean in turns. They actively work hard to reduce the amount of lean by using complex linkages, anti-roll bars etc. Looks like Mercedes is trying to allow for some amount of lean in turn by reducing the amount of anti-roll effort. In fact Mercedes is probably trying to reduce the weight and complexity of the suspension system.

      Bose, of the high quality speakers fame, did [bose.com]

    • It's about making people feel better about their car. Who cares about your outdated value-add notions like "efficiency" or "safety"? Pshhh! BTFD.

      • People who buy cars in this price range usually place efficiency and safety down the list of the must haves when buying a new ride.

    • by sjbe (173966)

      Suspension on cars do this automatically, already.

      No they do not. Traditional suspensions do exactly the opposite of what this system does. Traditional suspensions compress the springs on the outside of the turn rather than the inside. This is why you are pushed into the door instead of into the bottom of your seat.

      • by luckymutt (996573)

        This is why you are pushed into the door instead of into the bottom of your seat.

        Depending, of course, on what country you are driving in.

    • by AK Marc (707885)
      http://www.dailymail.co.uk/sci... [dailymail.co.uk]
      http://www.worldcarfans.com/111041532649/audi-a5-that-can-literally-lean-into-corners-video

      There are piles of leaning cars. Though, this might be the first one in the market. And I thought the Infinity Q45 with Active Suspension would lean in as well, but only as much as the forces were trying to make it lean out, so that it rode flat.
    • I've been thinking for a few minutes about the physics. It seems to me that automobiles cannot and will not actually benefit from this concept - it's all just feel-good nonsense, and marketing hype.

      First, unless you're a motorcycle rider, most people don't understand WHY a motorcycle leans. Motorcycle tires are not constructed the same as auto tires. Almost all the tires you have ever seen have a wide, flat surface that contacts the pavement. Motorcycle tires have rounded surfaces, with only a narrow pa

  • by 140Mandak262Jamuna (970587) on Sunday June 08, 2014 @02:07PM (#47190939) Journal
    Centrifugal force does not exist. It is a myth. It is a pseudo force. It is conjured up to explain the sensation of being pushed away from the center. Next time you are riding the car in a roller coaster tell yourself, "The centrifugal force is not real. When this car is upside down, there is no force pushing me up and pinning me to the seat. All physicists agree that centrifugal force does not exist" You will find it very reassuring.

    Oblig [xkcd.com]

    • by sir-gold (949031)

      Actually, the force that is pushing you against the seat is centripetal force, not centrifugal force.

      Centripetal force is the force of the chair pushing against you, because it's attached to the center and must travel in a circle (angular acceleration). Centrifugal force is the force that wants to send you and the seat flying off in a straight line (linear momentum). The only real force is the angular one, because there is a motor making the seat spin, everything else is just conservation of momentum.

      When t

      • by sjbe (173966) on Sunday June 08, 2014 @05:40PM (#47191881)

        Actually, the force that is pushing you against the seat is centripetal force, not centrifugal force.

        Depends on your reference frame [wikipedia.org].

        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.

        • by sir-gold (949031)

          Force requires energy, and the only energy being put into the system is rotational, therefore the only force is rotational, and everything else that appears to be a force is simply some aspect of momentum (which is merely an energy state, not a force unto itself)

          • Vectors 101 (Score:4, Informative)

            by sjbe (173966) on Monday June 09, 2014 @08:24AM (#47194041)

            Force requires energy and the only energy being put into the system is rotational, and everything else that appears to be a force is simply some aspect of momentum

            Congratulations, you just described movement in a non-inertial reference frame but you flunk vectors 101. Force requires mass and acceleration and nothing else - energy is merely a derived result in this case. The acceleration can be straight line or rotational. Acceleration occurs any time you have a change in velocity which is a vector. Change the magnitude (speed) or the direction (heading) and you have accelerated. So-called "fictitious forces" occur in the later case due to Newton's second law. The effects are real - they are only fictitious in the same sense that imaginary numbers [wikipedia.org] are different from "real" numbers. You need both "real" and "fictitious" forces to accurately describe certain phenomena and the force (or force-like depending on reference frame) effects are demonstrably very real. In curved spacetime, ALL reference frames are non-inertial and in the real world spacetime is curved as far as we can tell. So saying "fictitious forces don't exist" is equivalent to saying we live in flat spacetime. This does not match our observations.

  • Yeah. Right. (Score:4, Interesting)

    by Opportunist (166417) on Sunday June 08, 2014 @02:09PM (#47190943)

    It will be used for rider's comfort. Not to take corners faster. I'm amazed they don't pretend it's for safety, like all the other gadgets and improvements that, eventually, led drivers to drive faster and more risky because their gadgets allow even the worst driver to keep his car under control at higher speed.

    Which doesn't mean that I think anti-lock or traction control are bad things. Quite the opposite. But someone should tell the idiots that they were NOT meant to be used as a substitute for knowing how to drive, dammit!

    • by sjames (1099)

      This latest one might actually be a hazard. ABS and such provide some actual safety for less skillful drivers. This one cause the turn to feel less dangerous but does nothing to keep traction from breaking.

      • by sir-gold (949031)

        ABS is dangerous to people who learned to drive without 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.

        The only time I have ever slid though a stop sign in the snow was in an ABS vehicle.

        This is why they still offer cars with a "no ABS" option

        • Re:Yeah. Right. (Score:5, Insightful)

          by BitZtream (692029) on Sunday June 08, 2014 @04:55PM (#47191727)

          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.

          • by sir-gold (949031)

            You totally misunderstood me, and got oddly defensive of ABS (and abusive of me) for some reason.

            I never said ABS was bad (or in any way worse than non-abs) it's just incompatible with the braking style that people learn to use on non-abs cars, and leads to a longer braking distance that you would have otherwise gotten using that same technique with non-abs brakes

            Obviously ABS is better, IF you know the car has it, and IF you can control your reflexes well enough to use it right. For someone that grew up wi

          • by sjames (1099)

            But a person need not operate the brakes digitally. They can back off just a bit or brake just a bit harder. They don't have to decide between all or nothing 25 times a second. A really skilled driver in a familiar car can brake right up to the threshold without going over to get the maximum possible braking (no skid).

            There's also the question of how modern. I have seen tests where the skilled driver wins over the ABS but that wasn't with the latest and greatest ABS.

            • by wagnerrp (1305589)
              No they can't, because the threshold is continuously changing, there is no way to accurately know the position of that threshold, and once you cross the threshold, you have to drop way off to get back down below it. Operating it digitally is the only way to ensure you regain grip and maintain braking performance. It's a similar principle as to why it's easier to break AC than DC. You can build DC circuit breakers, but you need a lot of circuitry to provide that zero quench that AC experiences natively.
        • by sjbe (173966) on Sunday June 08, 2014 @05:53PM (#47191925)

          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.

  • American cars have been leaning over while turning for decades!
  • by mc6809e (214243) on Sunday June 08, 2014 @02:16PM (#47190983)

    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!

    • by PPH (736903)

      Drivers don't drive anymore. This sort of vehicle probably also comes equipped with automatic handling control systems.

    • by luckymutt (996573)
      Exactly this.
      While taking the El Cajon pass on the 15, no one should have any feeling except for how fast they are taking the turn. Providing a false sense of the turn is in no way helpful to anyone.

      /rant/ And it is ridiculous to site how motorcycles lean during turns. That is *how* motorcycles turn. Two-wheeled vehicles are completely different than cars. They counter-steer to turn.
      To turn left on a motorcycle, you don't "turn" left. You press on the left handle bar (pointing the front wheel to the
    • by geogob (569250)

      That's why the car is filled with other systems doing the feeling and adjusting for the driver, systems such as the ESP. it becomes essential in cars where de driving feeling disappears.

      But its Mercedes... I drive regularly fully equipped E class Mercedes. It's awful. Its full of systems driving for you and taking decisions for you... It can go as far as breaking you on the highway. These cars are at 90 degrees of the "driving feeling" concept.

      • by wagnerrp (1305589)

        These cars are at 90 degrees of the "driving feeling" concept.

        Of course it has nothing to do with feeling like you're in a performance vehicle. It has to do with being more comfortable, and we are more comfortable with positive Gs than lateral Gs.

  • by swell (195815)

    The car is designed to ride ~5 inches above the road surface. A normal car like this might tilt 2 degrees in a curve, toward the outside of the curve, causing that part of the car to be ~4 inches from the road surface. This Mercedes could conceivably tilt 2 degrees toward the inside of the curve, causing that part of the car to be about 4 inches from the road.

    The total difference between the tilt of a normal car and this Mercedes is perhaps 2 inches. Not at all like a motorcycle tilt in the same curve, in f

    • On the contrary, body roll is, in my admittedly subjective experience, quite noticeable. I drive two cars, a typical family car and a sporty two seater. The difference is night and day. One can easily feel the family car "sway" into and out of turns.

      Cars can gain traction in turns if body roll results in negative tire camber (especially on the outside wheel). I wonder if Mercedes has engineered a sort of reversed suspension to take advantage of this property. Or is that what they mean when they say t

      • by wagnerrp (1305589)

        Cars can gain traction in turns if body roll results in negative tire camber (especially on the outside wheel).

        That's not accurate. Cars have their best traction when at neutral camber, meaning the surface of the tire is flat against the surface of the road. In a turn, the outside tire will be loaded more heavily than the inside, and will tend to lean towards positive camber. Thus, if you "pre-stress" the suspension with negative camber, such that lateral load in the corner increases the tire to neutral camber, you will gain traction.

        Of course, setting up your suspension for negative camber will make your tire we

        • [Please read comments carefully before posting.]

          I stated the fact that many suspensions attain desirable negative camber while turning as a consequence of body roll. That cars are set up for neutral camber when driving straight is not at issue. The interesing part is that this Mercedes rolls the opposite way, and I wonder what changes were made to suspension geometry to account for this.

  • "Mercedes says it's not design for increasing cornering speeds, but increasing pleasure for the driver and passengers."

    Of course if it not literally going to make the car faster, but if you reduce the drag on the driver, the end result will be faster turns.

    • by mjwx (966435)

      "Mercedes says it's not design for increasing cornering speeds, but increasing pleasure for the driver and passengers."

      Of course if it not literally going to make the car faster, but if you reduce the drag on the driver, the end result will be faster turns.

      It will likely have the opposite effect. Increasing body roll in corners will make drivers think they're cornering faster than they really are, so most will go slower as not to increase the effect.

      Mercedes is really going backwards on this. Cars designed for cornering are designed to corner as flat as possible, sports cars and super cars are designed to reduce body roll as much as possible so they can actually get around a corner fast.

      • by wagnerrp (1305589)
        Actually, you have it backwards. They're generating body roll inward, so instead of feeling lateral Gs from the turn, the driver experiences positive Gs. The driver feels that the car is not turning as hard.
  • IIRC Volvo and Mercedes, and maybe some other car makers were working with active suspension systems that had this feature about 10 years ago. But IDK if it ever made it to a production model.

  • by matbury (3458347) on Sunday June 08, 2014 @03:02PM (#47191201) Homepage

    Mmm... lower perception of centripetal force may encourage drivers to go faster into corners. I remember reading comments supposedly from highway safety researchers that insulating drivers from road noise and vibrations, as modern cars do, reduces their perception of speed, thereby increasing the likelihood and severity of road accidents. Let's see what happens to accident rates on corners with cars fitted with this device.

  • by xeno (2667) on Sunday June 08, 2014 @03:37PM (#47191401)

    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 [youtube.com]
    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 [youtube.com]
    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.

  • by ildon (413912)

    posting to undo accidental moderation

  • It is a gimmick, and a welcome one. Makes the car feel like it turns like a plane or bike: by banking. Completely artificial but I'm tellin' ya, if I feel it I'll probably buy it.

    I don't like how cars and boats go about bends. I live with it, I choose my cars to make short work of the bends and have fun doing so, but I'd much rather feel a turn like in a plane or bike.

    Benz has been toying with this for at least 15 years, Some tv show had it, they also had a benz bike with four wheels which kinda scisso

    • by RJFerret (1279530)

      Try an Acura RL with SH-AWD first. The Benz system will obscure a bad road condition, causing you to drive with inaccurate information and potentially overdrive for conditions. The Honda system speeds up the outside wheels, effectively rotating the car à la a row boat, and it feels amazing, like you are accelerating down a straight road while actually sweeping a bend. Instead of the side bolsters pushing into you, the back of the seat pushes you from behind while you are in a turn. However it's not

  • "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.

    How am I suppose to get my knee on the ground from inside the car? Geesh.

    • by turp182 (1020263)

      Very dangerously, the key is not to fall out of the car while still maintaining control.

  • Mercedes says it's not design for increasing cornering speeds, but increasing pleasure for the driver and passengers.

    ...but is drivers discover that the new Mercedes has superior cornering ability that will be purely coincidental... honest...

  • increasing pleasure for the driver and passengers.

    Anyone else feel slightly dirty after reading that?

  • Didn't Citroen have this feature decades ago?

  • I think whatever focus group recommended this to Mercedes has trolled them very successfully. I'd think that this 'feature' would freak out people riding in the car and not be pleasurable.
    • by kimvette (919543)

      Quite a few sportscars have done this passively for decades - the first generation RX-7 was known for this. The difference is that passive suspensions on street cars do this only for low G-loads until the high CG overcomes the suspension and causes the weight to shift the lean outward, when the feature would be most beneficial to keep the car biased toward oversteer.

  • https://www.google.com/patents... [google.com] Might be slightly new in a production vehicle.
  • Can't wait until I'm 150% outside the cornering envelope when the system decides now is a good time to reboot.
  • First generation RX-7 did this passively at low to moderate G-loads but not at high G loads where it is more critical to bias toward oversteer. It's about time manufacturers are designing vehicles to do this actively.

  • by pmontra (738736) on Monday June 09, 2014 @03:00AM (#47193393) Homepage

    All Formula 1 cars had active suspensions in the early 90's. They were computer managed to keep the car flat in the curves and maximize aerodynamically generated downforce and also to absorb impact with kerbs in chicanes with almost no rebounds (more traction). Actually they were introduced by Lotus in the early '80s but didn't get mainstream because of weight and limitations in the electronics. Williams had a better version of them in their 1991 car (electronics got much better by then) and eventually all the team followed suit until FIA banned the technology starting from 1994 because of safety concerns (Zanardi barely survived a heavy crash [youtube.com] due to an active suspensions failure). More details on F1 active suspensions here [f1fanatic.co.uk].

    Production cars used them since the 80's [wikipedia.org].

    What Mercedes is doing now is reminiscent of the early Italian high speed train Pendolino [wikipedia.org]. "By tilting, the train could go around curves designed for slower trains at higher speeds without causing undue discomfort to passengers." See [youtube.com] one of those trains tilting in a curve in the UK in 2012.

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