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Filtering? — Parallax Forums

Filtering?

ThricThric Posts: 109
edited 2011-03-05 15:10 in Propeller 1
Does anyone have experience in sensor fusion and filtering methods using the Propeller? I know that Cessna Pilot (http://obex.parallax.com/objects/318/) created some really nice programs using the um-FPU however i was wondering if a program exists that does away with the external processor as its $20.

Thanks

Comments

  • Ahle2Ahle2 Posts: 1,179
    edited 2011-03-05 02:25
    Do you want to integrate a value over time or do you want some more advanced kind of filtering?
    How many samples per second and how many inputs?
    In one of my projects, I handle 16 analog inputs from a SPI ADC and integrate each value over time at a rate of ~6 kHz. This is all done in a single COG and then written to HUB ram.
  • ThricThric Posts: 109
    edited 2011-03-05 14:41
    well i'm kinda of a novice when it comes to filtering so i'm not really sure what type i'd need to fill my needs but i'll give the basics of what i'm trying to do:

    I'm trying to fuse/filter together acceleration, gyroscope, and magnetic sensor values (or maybe just two together like acceleration and gyroscope) to reduce the noise I get in each sensor and the drift that occurs too. I've hear about kalman filtering, but the math for it is way over my head.

    The sensors that i'm using are all digital however I'd like to have a refresh rate of at least 500Hz hopefully more.
    After being filtered/fused I want it to just write it to hub ram for another cog to use.

    Thanks
  • LeonLeon Posts: 7,620
    edited 2011-03-05 15:10
    A Kalman filter is often used for that sort of thing. I'd simulate the filter first, using something like Scilab. It'll save a lot of time.
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