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Input Shapers: 2HUMP_EI & 3HUMP_EI + Auto Tuning

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  • undefined
    carcamerarig
    last edited by 20 Mar 2021, 14:55

    @Argo said in Input Shapers: 2HUMP_EI & 3HUMP_EI + Auto Tuning:

    Since yesterday I'm testing Klipper at one of our printers. In particular the input shapers and their auto tuning with a ADXL345 accelerometer woke my interest.

    IMG_5303.jpeg

    It turns out my bed slinger printer (Bear Frame with Bondtech Extruder) has different resonance frequencies on each axis.

    After the auto calibration /measurement it recommended:
    Recommended shaper_type_x = 3hump_ei, shaper_freq_x = 61.4 Hz
    Recommended shaper_type_y = 2hump_ei, shaper_freq_y = 57.4 Hz

    I see there are input shapers on the way for RRF but I couldn't find exact infos what shaper will be used and if it will be possible to enter a shaper frequency for each axis separately.

    To sum it up, here are my wishes for RRF 3.4+:

    • support for a accelerometer (preferable ADXL345 as it's easy to find and buy) to measure the needed frequency. The input shapers 2HUMP_EI & 3HUMP_EI may need this as it can't be easily measured
    • Input shapers: 2HUMP_EI & 3HUMP_EI
    • separate frequencies and dampening for each axis (at the moment RRFs DAA uses the same frequency for both axis)

    Gets a +1👍🏼 Vote from me.

    1 Reply Last reply Reply Quote 0
    • undefined
      Argo @Egon.Net
      last edited by Argo 20 Mar 2021, 17:45

      @Egon-Net

      it's still a fast 32 bit board but I don't know if the available connections are fast enough for a accelerometer.
      But you could run Klipper with your Duet 2 🙂

      undefined 1 Reply Last reply 20 Mar 2021, 19:24 Reply Quote 0
      • undefined
        dc42 administrators
        last edited by dc42 20 Mar 2021, 17:46

        The accelerometer we are testing with is the LIS3DH. The Adafruit breakout board for it is widely available.

        Please note, the use of EI input shaping in 3D printers is patent protected. That's why we intend to support ZVDD as well.

        Duet WiFi hardware designer and firmware engineer
        Please do not ask me for Duet support via PM or email, use the forum
        http://www.escher3d.com, https://miscsolutions.wordpress.com

        undefined 1 Reply Last reply 20 Mar 2021, 19:31 Reply Quote 0
        • undefined
          zapta @Argo
          last edited by 20 Mar 2021, 18:35

          @Argo does Klipper support also backlash compensation? I wonder if the accelerometer can be used to calibrate it as well.

          1 Reply Last reply Reply Quote 1
          • undefined
            Egon.Net @Argo
            last edited by 20 Mar 2021, 19:24

            @Argo said in Input Shapers: 2HUMP_EI & 3HUMP_EI + Auto Tuning:

            @Egon-Net

            it's still a fast 32 bit board but I don't know if the available connections are fast enough for a accelerometer.
            But you could run Klipper with your Duet 2 🙂

            At leats be able to measure externally and input the results... (With and arduino, pc, whatever)

            1 Reply Last reply Reply Quote 0
            • undefined
              MikeS @dc42
              last edited by 20 Mar 2021, 19:31

              @dc42 please consider on supporting also ADXL345. It's the most common and cheapest one. I had one laying around that i used on my previous delta to do probing of the bed. I understand that, as a business, you have to come up with your own implementation and maybe better solution for the resonance problem, but klipper one for now would be great. We have time to improve it and have a better one!

              1 Reply Last reply Reply Quote 0
              • undefined
                dc42 administrators
                last edited by dc42 20 Mar 2021, 19:38

                LIS3DH boards from well-known suppliers such as Adafruit are half the price (or less) of ADXL345 boards.

                Duet WiFi hardware designer and firmware engineer
                Please do not ask me for Duet support via PM or email, use the forum
                http://www.escher3d.com, https://miscsolutions.wordpress.com

                undefined undefined 2 Replies Last reply 21 Mar 2021, 00:20 Reply Quote 1
                • undefined
                  Argo
                  last edited by 20 Mar 2021, 19:51

                  The ADXL345 cost me 6 EUR and a LIS3DH would cost me 10 EUR.
                  But honestly I don't really care if I had to buy another one for my Duet / RRF.

                  @zapta said in Input Shapers: 2HUMP_EI & 3HUMP_EI + Auto Tuning:

                  @Argo does Klipper support also backlash compensation? I wonder if the accelerometer can be used to calibrate it as well.

                  It's measurable, so yes.

                  1 Reply Last reply Reply Quote 0
                  • undefined
                    zapta @dc42
                    last edited by 21 Mar 2021, 00:20

                    The Adafruit LIS3DH is available in my country on Amazon, $7 Prime shipped.

                    https://www.amazon.com/Adafruit-LIS3DH-Triple-Axis-Accelerometer-ADA2809/dp/B01BU70B64

                    @dc42, will input shaping be supported on stand alone Duet2 Wifi?

                    undefined 1 Reply Last reply 21 Mar 2021, 09:41 Reply Quote 0
                    • undefined
                      dc42 administrators @zapta
                      last edited by 21 Mar 2021, 09:41

                      @zapta said in Input Shapers: 2HUMP_EI & 3HUMP_EI + Auto Tuning:

                      The Adafruit LIS3DH is available in my country on Amazon, $7 Prime shipped.

                      https://www.amazon.com/Adafruit-LIS3DH-Triple-Axis-Accelerometer-ADA2809/dp/B01BU70B64

                      @dc42, will input shaping be supported on stand alone Duet2 Wifi?

                      Yes, but perhaps not on the Duet Maestro because it doesn't have floating point hardware.

                      Duet WiFi hardware designer and firmware engineer
                      Please do not ask me for Duet support via PM or email, use the forum
                      http://www.escher3d.com, https://miscsolutions.wordpress.com

                      undefined 1 Reply Last reply 23 Apr 2021, 03:42 Reply Quote 1
                      • undefined
                        MikeS @dc42
                        last edited by 6 Apr 2021, 14:35

                        @dc42 no problem at all at buying another accelerometer, but just for reference, amazon IT has ADXL345 at €5.99 with prime, LIS3DH €15.46 with prime. Most important is: are there differences on precision of the readings between these 2? 10€ difference is not a problem compared to accuracy of readings

                        1 Reply Last reply Reply Quote 0
                        • undefined
                          printernoodle
                          last edited by 8 Apr 2021, 23:20

                          I am looking forward to this feature set...

                          undefined 1 Reply Last reply 9 Apr 2021, 06:40 Reply Quote 0
                          • undefined
                            dc42 administrators @printernoodle
                            last edited by 9 Apr 2021, 06:40

                            More at https://duet3d.dozuki.com/Wiki/Accelerometers, and sample results at https://forum.e3d-online.com/threads/accelerometer-and-resonance-measurements-of-the-motion-system.3445/#post-38177.

                            Duet WiFi hardware designer and firmware engineer
                            Please do not ask me for Duet support via PM or email, use the forum
                            http://www.escher3d.com, https://miscsolutions.wordpress.com

                            undefined undefined 2 Replies Last reply 9 Apr 2021, 06:54 Reply Quote 0
                            • undefined
                              zapta @dc42
                              last edited by 9 Apr 2021, 06:54

                              @dc42 said in Input Shapers: 2HUMP_EI & 3HUMP_EI + Auto Tuning:

                              sample results at https://forum.e3d-online.com/threads/accelerometer-and-resonance-measurements-of-the-motion-system.3445/#post-38177.

                              @dc42, Can you post the graphs here? E3D requires registration to view them.

                              undefined 1 Reply Last reply 9 Apr 2021, 07:38 Reply Quote 0
                              • undefined
                                dc42 administrators @zapta
                                last edited by dc42 4 Sept 2021, 07:42 9 Apr 2021, 07:38

                                The first two are without input shaping. The second two are with ZVD input shaping at 42Hz. ZVDD didn't give any further improvement, and both EI2 and EI3 were worse.
                                0d5110bc-f848-454d-a26c-4568a616300c-image.png
                                f95107ba-7062-41b5-961c-229f76fbd778-image.png
                                cf4f4823-a967-4c6d-ad99-dd6946f217cc-image.png
                                d414cb9b-3770-49d6-aa7b-c95835149457-image.png

                                Duet WiFi hardware designer and firmware engineer
                                Please do not ask me for Duet support via PM or email, use the forum
                                http://www.escher3d.com, https://miscsolutions.wordpress.com

                                undefined 1 Reply Last reply 9 Apr 2021, 07:44 Reply Quote 2
                                • undefined
                                  Argo @dc42
                                  last edited by 9 Apr 2021, 07:44

                                  Very nice seeing progress there!
                                  Also as usual it looks very tidy and well thought out so far.

                                  just ordered a Adafruit LIS3DH and plan to experiment with the new feature.
                                  I see (experimental?) input shapers are also already implemented in the 3.3-input-shaper branch.

                                  Is it already worth to try and experiment with the feature also during printing conditions?
                                  Would like to see how the input shapers work with a typical i3 bed slinger as these printers tend to have different ringing frequencies at once. And I also could provide some results/data.

                                  undefined 1 Reply Last reply 9 Apr 2021, 10:53 Reply Quote 0
                                  • undefined
                                    dc42 administrators @Argo
                                    last edited by dc42 4 Sept 2021, 10:54 9 Apr 2021, 10:53

                                    @argo said in Input Shapers: 2HUMP_EI & 3HUMP_EI + Auto Tuning:

                                    I see (experimental?) input shapers are also already implemented in the 3.3-input-shaper branch.
                                    Is it already worth to try and experiment with the feature also during printing conditions?

                                    Experiment if you like; but the code is by no means complete, so be very careful. Pressure advance is disabled - I haven't even tried extruding. Delta kinematics is not implemented.

                                    Input shaping will only work on moves for which the acceleration time is long enough to apply it, i.e. at least 2 * the shaping time. So you may need to reduce acceleration to get it applied. I believe there is some scope to apply it to shorter acceleration times, down to 1 * the shaping time + one half period, at least when using ZVD or ZVDD, but that isn't implemented yet. Also I will probably implement reducing acceleration (but not below a minimum) where necessary to allow input shaping to be applied.

                                    I don't expect to include the input shaping code in the 3.3 release.

                                    Duet WiFi hardware designer and firmware engineer
                                    Please do not ask me for Duet support via PM or email, use the forum
                                    http://www.escher3d.com, https://miscsolutions.wordpress.com

                                    CNCModellerundefined 1 Reply Last reply 9 Apr 2021, 12:34 Reply Quote 1
                                    • CNCModellerundefined
                                      CNCModeller @dc42
                                      last edited by CNCModeller 4 Sept 2021, 12:38 9 Apr 2021, 12:34

                                      Hi All,
                                      Can anyone recommend a link to a good article on what input shaping is and what print features it addresses? I'm assuming it's about removing excitation of the printers structural modes from the demand, but I guess there are more subtle nuances too.

                                      Edit: I assume this is the accelerometer mentioned.

                                      https://www.ebay.co.uk/itm/232427148679

                                      Many thanks
                                      Barry M

                                      Polar Duet3 Mini + 1HCL
                                      https://youtube.com/playlist?list=PLWjZVEdMv1BY82izahK45qKh-hp3NFkix
                                      Wanhao D4S: Duet2
                                      https://forum.duet3d.com/post/296755
                                      K40 Laser, Duet2
                                      https://forum.duet3d.com/post/312082
                                      Wanhao D5S
                                      https://www.youtube.com/CNCModellerUK

                                      undefined 1 Reply Last reply 9 Apr 2021, 13:51 Reply Quote 1
                                      • undefined
                                        Argo @CNCModeller
                                        last edited by 9 Apr 2021, 13:51

                                        @cncmodeller

                                        Yes that's the sensor.

                                        Input shaper ZVD(D) paper:
                                        https://www.researchgate.net/publication/316556412_INPUT_SHAPING_CONTROL_TO_REDUCE_RESIDUAL_VIBRATION_OF_A_FLEXIBLE_BEAM

                                        EI2 input shaper:
                                        http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.465.1337&rep=rep1&type=pdf

                                        Most simple explanation: It basically cancels out ringing frequencies.

                                        @dc42
                                        Defining a minimum and maximum acceleration range might be good approach for input shaping.
                                        With Klipper's (automatic) calibration measurement you can set a "max smoothing target" as too much acceleration may lead to losing fine details. It then recommends to stay below a specific acceleration, depending on the used shaper the value differs.
                                        What Klipper does not offer though is to set a specific acceleration range. Meaning, if printing small details, the acceleration slows down as needed, so the shaper works properly.

                                        Speaking of pressure advance. Is some sort of pressure advance smoothing planned?

                                        1 Reply Last reply Reply Quote 2
                                        • undefined
                                          Dougal1957
                                          last edited by 9 Apr 2021, 14:04

                                          I have just order two of these https://shop.pimoroni.com/products/adafruit-lis3dh-triple-axis-accelerometer-2g-4g-8g-16g in anticipation.

                                          Doug

                                          undefined 1 Reply Last reply 9 Apr 2021, 14:11 Reply Quote 0
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