Input shaping

Discussion in 'Motion System' started by Andy Cohen, Aug 1, 2022.

  1. Andy Cohen

    Andy Cohen Well-Known Member

    Joined:
    Aug 23, 2019
    Messages:
    277
    Likes Received:
    63
    As I recall, last I heard from DC42 Input Shaping only works on single board setups. I assume this means the setups we use for the TC therefore won't use the shaping profiles to cancel out resonance. Is this still the case?

    I finally got around to updating my DuetCloneR1 and mounted up and wired an accelerometer board. The result I got was good.
     
  2. Paul Arden

    Paul Arden Well-Known Member

    Joined:
    Aug 28, 2019
    Messages:
    182
    Likes Received:
    59
    I’m not aware of any such restriction at least in RRF3.4.1. I hooked up the accelerometer and used the input shaping plugin to tune it in the UI, re-ran the tests with the shaping enabled and the results definitely showed the difference. I’m on the standard E3D Toolchanger electronics so Duet2 WiFI and Duex5.
     
  3. Andy Cohen

    Andy Cohen Well-Known Member

    Joined:
    Aug 23, 2019
    Messages:
    277
    Likes Received:
    63
    Well then I guess it is finally time for me to update my FW!
     
  4. dc42

    dc42 Well-Known Member

    Joined:
    Aug 16, 2016
    Messages:
    526
    Likes Received:
    221
    Input shaping currently only works on motors driven from the main board or a directly-connected expansion board, not on motors connected to a CAN-connected expansion board.
     
  5. Andy Cohen

    Andy Cohen Well-Known Member

    Joined:
    Aug 23, 2019
    Messages:
    277
    Likes Received:
    63
    Paul... could you please share your config.sys file?
     
  6. Paul Arden

    Paul Arden Well-Known Member

    Joined:
    Aug 28, 2019
    Messages:
    182
    Likes Received:
    59
    For the accelerometer I added the following line:

    Code:
    M955 P0 I24 C"spi.cs4+spi.cs3" ; LIS3DSH accelerometer
    
    I have the LIS3DSH model, just from some random Aliexpress vendor. In my case I temporarily mount it just to take measurements then remove it (I have a Molex Microfit 3 connected pair setup to make that easier. I use the Input Shaping Plugin to take the measurements and test the different frequencies then once I had picked the one I thought gave the best results in the graphs I added the following line to my configuration to activate it:

    Code:
    M593 P"mzv" F43.4             ; Enable MZV input shaping at 43.4Hz, accelerometer measured
    
    Obviously the frequency on different machines is likely to be different. I measured with each of my tools attached to see if there was much difference between them but there didn't seem to be (although the only variation in my tools is that two are Volcano).

    My setup is stock in terms of electronics, so Duet 2 WiFi + Duex 5.
     
  7. GoffyOne

    GoffyOne Member

    Joined:
    Sep 16, 2019
    Messages:
    8
    Likes Received:
    0
    Thinking of getting this set up also, any like step by step how to install the accelerometer, does it need to be on each tool or on the toll holder?
    Any 3d models to print to hold the accelerometer? Do you just do an analysis of the frequency and then set it up in the config, and then the accelerometer can be removed again? Kind of thought it kind of analyze and compensate for it in real time somehow.
    I do have the Duet 2 WiFi + Duex 5.
     
  8. dc42

    dc42 Well-Known Member

    Joined:
    Aug 16, 2016
    Messages:
    526
    Likes Received:
    221

Share This Page