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Thread: Make Do-It-Yourself Sideslip Sensor.

  1. #1
    Senior Member
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    Make Do-It-Yourself Sideslip Sensor.

    Then you can design a car's tire, chassis and steering performance, validate your design with direct measurements and turn your Wrench hat in for a Engineer's cap.

    https://pixhawk.org/modules/px4flow

    This can also settle the noisy discussions about Understeer, Moment Methods, Tire Size and Testing Best Practise Methods. And it just might get you invited to work for a real race team instead of an old school one.

  2. #2
    Quote Originally Posted by BillCobb View Post
    Then you can design a car's tire, chassis and steering performance, validate your design with direct measurements and turn your Wrench hat in for a Engineer's cap.

    https://pixhawk.org/modules/px4flow

    This can also settle the noisy discussions about Understeer, Moment Methods, Tire Size and Testing Best Practise Methods. And it just might get you invited to work for a real race team instead of an old school one.
    Bill,

    The only real problem that I see with this set up is the required focal distance above the ground and the limitation it brings with max velocity.

    Max velocities for different focal length lenses and ground distances:

    Grounddistance 1m 3m 10m
    16mm lens 2.4m/s 7.2m/s 24m/s
    8mm lens 4.8m/s 14.4m/s 48m/s
    6mm lens 6.4m/s 19.2m/s 64m/s
    4mm lens 9.6m/s 28.8m/s 96m/s
    Kettering University Vehicle Dynamics
    Formula SAE 2010 - 2015
    Clean Snowmobile Powertrain 2012 - 2015

    Boogityland 2015 - Present

  3. #3

  4. #4
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    Pretty crippling deadband they've got there
    Formula SAE: When you just can't get rid of a girlfriend.

  5. #5
    I like the stick-a-wire-on-a-potentiometer-and-drag-it-on-the-ground method. Simple to implement and pretty cheap. Probably not as responsive as a visual sensor, but that would just take a bit of testing.
    Jay Swift
    Combustion Powertrain
    Global Formula Racing 2013-2014

  6. #6
    Quote Originally Posted by Pennyman View Post
    Pretty crippling deadband they've got there
    They mentioned that the mouse sensor has a +-5deg deadband when the motion is aligned to an axis (X or Y), so they rotated the sensor by 45deg relative to the car (so the sensor sees 45deg at 0 slip angle). This gives them +-40deg of slip angle measurement before they hit the deadband. So no deadband in practice.
    Andrew Palardy
    Kettering University - Computer Engineering, FSAE, Clean Snowmobile Challenge
    Williams International - Commercial Turbofan Controls and Accessories

    "Sometimes, the elegant implementation is a function. Not a method. Not a class. Not a framework. Just a function." ~ John Carmack

    "Any sufficiently advanced technology is indistinguishable from magic" ~Arthur C. Clarke

  7. #7
    Quote Originally Posted by rory.gover View Post
    Can't speak to the accuracy of all the content, but: http://journals.sfu.ca/vte-j/index.p...icle/view/6/11
    I've been waiting for that article to be published, and completely forgotten about it. Thanks for bringing it up.
    The interesting part is that mouse technology has advanced fair enough just in the development of that project that those sensors are now obsolete and replaced by even better candidates.
    It does address the one thing issue I see with Bill's suggestion by applying a new lens to the sensor.




    Neat.
    Kettering University Vehicle Dynamics
    Formula SAE 2010 - 2015
    Clean Snowmobile Powertrain 2012 - 2015

    Boogityland 2015 - Present

  8. #8
    Quote Originally Posted by MCoach View Post
    I've been waiting for that article to be published, and completely forgotten about it. Thanks for bringing it up.
    The interesting part is that mouse technology has advanced fair enough just in the development of that project that those sensors are now obsolete and replaced by even better candidates.
    It does address the one thing issue I see with Bill's suggestion by applying a new lens to the sensor.




    Neat.
    Sorry for also forgetting to post it here once it was published. It's kinda nice to see my paper being read and spread around.

    MCoach, you are correct, and the current design I am playing with, amongst a bunch of other improvements, is now based around a PWM3310, and I'd say that there would be better once again since designing that board early this year.
    Nathan Tarlinton
    UOW FSAE 2010 - 2013

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