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Thread: Active suspension design engineer - Boston, MA

  1. #11
    Senior Member
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    Shocking

    No question that such a system can allieviate a limited psd spectrum of roadway bumps and holes. Our findings with the Lotus Active and Bose "Voice Coil" actuation were that owners will increase their speed as the apparent confidence in the lower vertical acceleration profile increases. However, taking a 5g vertical jerk on a minimum of just one side of the car calls for large increases in chassis and body structure to contain the required suspension forces. Sure, do the dog leg rising for a speed bump or a tar strip, but extending the spindle at 250 Hz trigger signal will take some downforce. But back to my original questions: HOW MANY JOULES per mile can your afford ? What is the power source ? Gigantic capacitor ? Be sure to warn EMS workers about it. When you try to jump a curb, who wins (tire, wheel, control arm or actuator) ? Need a lot of wheel travel for it. There's going to be some tire scrub and tire wear will play into the cost of ownership.

    One neat aspect of such a system is the ability to adjust ride height(s), even to the point of banking roll in a turn.

    I would NOT tell the road commissions about the location of potholes. What do you expect a high end purchaser to feel, if they find out their car is paving the way (so to speak) to fix roads so other vehicle owners will ride better ? That's like me buying a county snow plow so I can get to work during a blizzard. Will everybody want to leap out and buy a snow plow ?

    I've worked on two active systems, one was a fluid leaking software nightmare. The other was cool but was too costly and gulped too much energy to be acceptable to range conscious owners. Weight is an issue too, not just for the substitute parts but for the chassis structure to hold onto the loads. And then there will be warranty costs and of course the ambulance chasers. "My client assumed you could jump the Grand Canyon with their new Ferrari and look what they turned into". (a vegetable is worse=lifetime cost of ownership). Its Big Science of course, and all the OEM will want to try it out. But just like Shark Tank, "I'm out". Oh, and NBC ? Ha, Ha, Ha, I saw them blow up gas tanks with rocket engines, remember ? They proved that it actually takes several tries to burn down a truck...

    nusquam est vere novus. (Help me, I sound like Z).

  2. #12
    Quote Originally Posted by DougMilliken View Post
    Where are the potholes? The bumps/ramps shown in that video are fairly long wavelength, and appear to be "tuned" to the roll resonance of the passive car--making it look violently bad.
    + Those are not typical road bumps, so of course the standard Merc was not tuned for them. Why were they chosen for this demo?
    + Have you got a video that shows realistic potholes, taken at a variety of speeds?
    We've had video of these ramps being used to compare to various passive and semi-active cars available for years. They are not tuned to any specific cars roll resonance its simply a demonstration for the laymen to see what the system can do in an exaggerated form. I don't think we're making anything public yet with regards to certain types/sizes of pot holes or "cleat" events. Mostly because we're still developing/tuning and improving every day so there is no reason to share that info unless you want to be an investor. This weekend will be the 2nd time I'll get to drive one of the cars from Boston to Philly and really enjoy taking notes on what is working well and what isn't which gets fed back into the systems tuning group. Obviously through NY, NJ, and Philly there are plenty of pot holes to hit and I can say the system works well. This is on a car without our road sensing tech (seeing the pothole before hitting it and reacting) which I think will change the game entirely.
    Ryan M.

  3. #13
    Quote Originally Posted by BillCobb View Post
    But back to my original questions: HOW MANY JOULES per mile can your afford ? What is the power source ? Gigantic capacitor ? Be sure to warn EMS workers about it. When you try to jump a curb, who wins (tire, wheel, control arm or actuator) ? Need a lot of wheel travel for it. There's going to be some tire scrub and tire wear will play into the cost of ownership.
    I'm not going to get into specifics but seemingly unlike you're previous experience we have regen capability so our energy usage data so far is negligible.
    Ryan M.

  4. #14
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    Quote Originally Posted by RBbugBITme View Post
    ...to see what the system can do in an exaggerated form. ...
    How does Mercedes Magic Body Control (optional from 2014 model year, I believe) do over those same ramps?
    Are you (or the MBC) as good as the chicken<grin>? https://www.youtube.com/watch?v=nLwML2PagbY

  5. #15
    That is a great commercial. Not even sure how their system works, I'm not the guy looking at the competition.

    Edit:
    Looks like their original version was an active spring with a semi-active damper. So lower bandwidth and may or may not be able to respond fast enough for that ramp demonstration. Supposedly a 2% take rate so no one was willing to pay for it.
    Last edited by RBbugBITme; 05-04-2018 at 12:32 PM.
    Ryan M.

  6. #16
    really awesome website by the way

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