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Cornering friendly ABS is not coming anytime soon.

Discussion in 'General Motorcycling Discussion' started by robsalvv, Jul 23, 2011.

  1. http://www.visordown.com/motorcycle...-soon/18637.html/v/1/SP/622991256588496991408

    Cornering ABS: Not coming soon

    Tabloid red-herring. For now.

    Posted: 22 July 2011
    by Mark Forsyth


    ON OUR recent trip to the Bosch test facility in Germany, their boffins teased us with news that they're developing an ABS system that works when the bike is leaning and turning.

    Their very neat and compact SU-MM5.10 lean angle sensor is capable of measuring yaw, roll and acceleration in three planes and samples at more than 100 times per second. It's processors like this that enable anti-wheelie and launch control systems to operate.

    When pressed on the actual feasibility of perfecting cornering ABS their answers sounded like they'll never actually crack it because to remove that level of control from a rider is a hot bed of legal responsibility. Recent reports in another motorcycle publication claiming that this system is 'coming soon', appear to be misleading. It's not coming soon and if it is, it'll be a very rudimentary system that 'assists' the rider rather than doing the job of full ABS at full lean. That, after all, would be nigh-on impossible.

    Here's just one instance why. There are times when carrying a lot of front brake - trail braking - into a turn helps the bike actually turn by compressing the forks and therefore reducing the trail and effectively steepening the head angle by pitching the whole bike forward through its steering axis. For the skilled rider, it can be a particularly useful technique to deal with a tightening radius corner. Cornering ABS will not allow you to do this, either. As the front tyre begins to reach its limits of grip the ABS will switch braking force to the rear. Can you imagine how horrible that would be? The whole attitude of the bike would change almost instantly, forcing the machine to change line and run wide. Not great on a left-hander. Also, how would the system differentiate between individual riding skills? Answer: it can't.

    And while it's relatively easy to measure and calculate lean angle, there's no way that technology can determine grip levels which often have to 'felt' by the rider. In a corner - far more than in a straight line - weight distribution and braking force are a crucial part of what makes riding a motorcycle so hard - yet so enjoyable.

    Despite some very clever and super-fast processing speeds and sensors, building an ABS system for bikes that works in corners is not happening anytime soon. Claim culture will put paid to that. Bosch, however are continuing their R&D in association with an un-named manufacturer.

    Don't hold your breath.

    = = = = = = = = = = = = = = = = = = = = = = = = = = = =
    IIRC Honda had a corner suitable ABS on a race bike, but the system added 20lbs to the bike... that's 9 kg - pretty significant weight disadvantage.

    Bosch recently seemed to be skiting about them developing corner friendly ABS on their small ABS module... seems like it was all show.

    Speaking of ABS, the UN/ECE rules are madating ABS for all bikes >125cc by 2017 - but it seems they've partially seen sense and not made it mandatory for offroad and trials bikes... it's still not a switchable option though for all the rest, and to discourage people adding switches, they are floating anti tampering laws. Bureaucracy gone mad!

  2. Wow! So systems like these wont actually make the bike smarter it will just make the rider dumber. Fuck me, who knew?
  3. Ugh mandatory ABS, what about the people who only ride their bikes on nice days for pleasure, why do they need a system that only really helps a great deal when in the wet, it is unlikely that they will be doing much riding in these conditions.

    Enough with the legislation. Most people can manage their own freaking lives.
    As for mid corner ABS, im glad it doesn't / wont probably ever exist.
  4. ...but it does exist... every bike with ABS will still ABS mid corner... but the ABS is only built for a vertical braking scenario... it doesn't switch off when there's a corner.
  5. Having an ABS that was calibrated for normal straight ahead riding would still be better than nothing, but to work properly while leaned over it would have to sense wheel speed very frequently and intervene very quickly. Then you get the problem that it comes on too early and starts compromising normal braking.

    One of the objections to ABS in cars, in Australia, was that it could sometimes dramatically increase stopping distances on some kinds of dirt and gravel road. One solution to that was to turn down the speed of the cycle, so it samples speed and intervenes much less frequently, allowing the wheel to partly lock (or at least dramatically slow) before it activates.

    To make an effective motorcycle ABS for corners, you'd have to go the other way. Now what effect would that have on gravel roads?

    Another thought - ABS will trigger if one wheel decelerates very sharply, but it can also trigger if it notices a differing speed between the two wheels. When a tyre gets under pressure, it can turn faster for the same road speed. Say you got a flat rear tyre, or almost flat, and you had to stop sharply. You could trigger the ABS on the front just by rolling off the throttle.

    Broadly speaking, you can build a system that's going to work and work well, in a fairly narrow range of conditions, but what'd be extremely difficult would be to build a system that worked faultlessly in all conditions.

    Example: The previous model Fireblade has a steering damper controlled by the ECU. It turns the damper up and down over a pretty broad range of settings based on speed, throttle opening, and a couple of other things - I forget exactly. It's not a terribly complex system, anyway. So a journalist asked at the world press release whether the thing could ever make the wrong call, and put the rider in a bad spot. The engineers from honda smiled aand explained in a patient and fatherly way that they'd looked at everything and nothing could go wrong. The next day, within the first half hour of journos getting handed the keys, one came back into the pits to find his photographer there with the camera up, motioning to do a mono. So he popped it up, turned the bars full lock and leaned around the side to look at the camera. Click. Great photo. Bike doing about 40km/h. So then he killed the throttle and dropped it back down. The front wheel touched the ground at full lock and stayed at full lock. What do you think happened next?

    I've personally met two people who've crashed 05 ~ 07 'blades because (in part) the steering damper suddenly changed setting in the middle of something, and a couple of others who've dropped them for reasons they clearly don't properly understand, which may have been influenced by the same problem.
  6. And current ABS only operates when one or both wheels has begun abnormal deceleration; i.e. the tyre's gone past even the optimal amount of slip for maximum grip (~12%) and in a few short moments will be a fully-locked wheel.

    What happens to a bike with a fully-locked wheel when it's on a steep lean? I think the term is "up shit creek without a paddle at that point".
  7. Or dumarse people, able to ride a bike.
    I'm all for some technological advancements, that help a good rider, ride good, but nothing is sacred any more.

    Thanks for spotting that one Rob. I think they're messing with areas that should be left alone.
    A bike can't just be a good bike anymore. Designers will get lazy and dumb down the bikes poor design with tech assists, that should'nt or would'nt be needed if the design was spot on.
    Ahr well.
  8. Rather than using near instantaneous sample rates and pre-processing technology for yaw, pitch and throttle position to engage ABS or not - wouldn't a very simple (and consistent) mercury orientation circuit work better?

    The circuit will be NC (Normally Closed) for upright riding <= 10 deg (say)
    Any larger angle will open the contact and disengage ABS - job done......???
  9. Watching some rally highlights on the box today, there was an interview with an older bloke driving an early Porsche RS (and leading the field...).
    His take was that if you want to see a real "driver", you look at the older cars without ABS, TCS etc - all the newfangled techwizardry simply made it easier for a less-skilled driver to compete.

    I'm not sure if it's relevant though, that he lost the rear on the next stage, developed a tankslapper and rolled the thing off an embankment?
  10. Succinctly, no, because just like an aeroplane, the angle the bike's leaning relative to the planet, the size/shape of the corner it's following and the directions and magnitudes of the accelerations imposed upon the bike by gravity, cornering and so on bear little resemblance to one another.

    Which is why that tail-cowling camera on the back of some of those MotoGP bikes uses a relatively expensive and complex gyroscopic doohickey to keep the camera level rather than having it on a much-simpler-and-cheaper swinging pendulum or similar.
  11. Hmmm.
    A sufficiently-damped pendulum would do effectively the same thing.
    I thought they used a gyro cos it's smaller and lighter...
  12. Hmmmm....granted and sensible -

    However as a mercury switch would also be effected by the orthogonal force applied through an acceleration arch surely there would be a simple calibration curve for such a device?

    I just reckon that a simple approach with a binary logic rather than a fuzzy logic would make this scenario better?
  13. if they're going to use gyros and other, as you say, doohickeys, I wish they'd use them to make useful headlights, instead of trying to second-guess the rider....

  14. .....
  15. BMW have done that on their K1600GT... very complex bit of kit.
  16. if it made riding at nightime safer, I'd pay for it

    {but I'll never be able to afford te bike that goes with it :( :LOL:}
  17. I volunteered to join the orthogonal force, but they didn't accept me. Not tall enough, or something...

    Paul, have you seen the peering-around-corners headlight which is available on heli's K1600 Boomer?

    It must be said that cars have played with this idea (in yaw, not yaw + roll) since at least as far back as the 1950s, and while it's supposed to work ok when everything is working, it's mostly more trouble than it's worth and widely regarded as an expensive gimmick.
  18. Rob, you may be interested in a story that skipperau tells, of almost missing his exit on the freeway in the pissing down rain, on the FJR, because he was half asleep or texting or something, so he hurled it left and grabbed a handful of brake, and had the ABS trigger. He swears the front tucked a fraction and the ABS shuddered for a couple of seconds and he sat there like a rabbit in the headlights, but the system worked. He says the bike was not lean over scraping far, but it was sure as hell not upright.
  19. oh yeah, Citroen had it in the later model DS-19/21s, but looking roudn corners in a car is a whole lot easier than on a bike

    anyway, this thread is about ABS, so I'll shut up whining about headlights :LOL:
  20. I'm not against ABS mate. Just mandatory ABS. Glad to hear your mate survived the brain fart.