9 Replies Latest reply on Jun 13, 2009 12:02 AM by Ian Hogg

    Circular motion

    oren wein
      Hi.

      I assembled an Izod machine (to make the simulation faster I suppressed most of the parts and leave only the parts for the Circular motion) and I'm trying to simulate it.
      I chose the gravity simulation ( all the mates are fine-beacuse when I move the Pendulum it moves in the right directions-in Circular motion)
      BUT when I try to simulate it, the Pendulum stops after it passes the lower point instead of continue to the same Height it began (as it should accroding to the Potential energy)
      even the velocity is the same along the simulation (and it shouldn't be)

      can someone please help to figure it out.

      Thanks.

        • Circular motion
          Ian Hogg
          Hi Oren,
          Which motion product are you using (ie basic motion or motion analysis)?
          I would recommend motion analysis for accurate representation of this (true mass & inertia response relative to time).
          If you're able to post the model to be reviewed, that takes the guess work out of troubleshooting blindly.
          Cheers,
          Ian
            • Circular motion
              oren wein
              Hi.

              Thanks for your help I attached the assembly.
              PLease advice.

              Oren.
                • Circular motion
                  Ian Hogg
                  Hi Oren,
                  Unfortunately you file nameas have chanracters I cannot read in the English version of Vista. What language are they saved in?
                  Cheers,
                  Ian
                    • Circular motion
                      oren wein
                      Hi again.

                      I forgot to change the named of the parts from hebrew to english (sorry).
                      anyway, now I changed it and attached it again.
                      hope mow it's OK.

                      Thanks again.
                      Oren.
                        • Circular motion
                          Ian Hogg
                          Hi Oren,

                          The assembly is still a mess. It's looking for a hammer3.sldprt and then some hebrew labeled files still. It's tricky to rename files on the fly. SW Explorer can do a reasonable job of it usually. Try using pack and go to export the zip file.

                          Worst case would be to just save the assembly as a parasolid and add a couple of images showing mates.

                          Ian
                            • Circular motion
                              oren wein
                              Ian, Hi again.

                              I built it from the begining and I made sure that nothing in hebrew and I even tried to open it myself (after I changed all parts from hebrew to english), it seems fine now .

                              Please open assembly named "base1"- I unsrstood what was my problem before and I fixed it.

                              many thanks for your help and patience Irealy appreciate it.

                              Oren.
                                • Circular motion
                                  Ian Hogg
                                  Hi Oren,
                                  I am guessing you have 2008 since my version says the files are old and it appears you are using basic motion. If you have SolidWorks premium, I really urge you to consider Motion Analysis for this application. It will give you accurate results, whereas basic motion is not necessarily realistic. It has some representation of mass and inertia, but it is not an accurate physical representation. You will see on the forum there is quite a bit of comment on how sensitive it can be (to get it working).

                                  Anyway, I looked at the model and the first thing you should always do with motin is simplify things into the least number of moving parts. This really simplifies the mathematics for determining the resulting motion. For your model, I made to top level assemblies and grouped everything into these.

                                  I removed the contact since it is of no value in the current model. Once you add a test specimen for it to strike, it would be worth adding back in. Always minimally define contact only between those things that you expect to collide. Anything beyond that is uneccessary overhead.

                                  The model ran fine at 16 frames per second. I tried 30 and it went strange (it only moved a portion of the path in 5 seconds!), so be wary when adjusting the fps. Don't ask me why, but that's why I like the full motion module.

                                  I've attached a movie to show the setup and resulting motion from my assembly. I hope this helps you structure yours accordingly.

                                  Cheers,

                                  Ian
                                    • Circular motion
                                      oren wein
                                      Hi Ian.
                                      I Actually have no words to describe your kindness and again patience to help.
                                      It realy makes me feel happy to see people who are so willing to help.
                                      I wll try to copycat what you done with the assembly, unfortunately I have only solidworks 2007 and I don't think I havr the same application you used but you gave me hope (I will even consider to install solidworks 2008)
                                      I wil try.

                                      again many many thanks for your investment to help me.

                                      Oren.

                                      I edit my message to tell you that I succeed to do it, with a great help from you.
                                      Thanks.
                                      :-)
                                        • Circular motion
                                          Ian Hogg
                                          Hi Oren,

                                          If you have 2007, then you need COSMOSMotion 2007.
                                          Iteractive physics, which is the animation engine does what I call quasi-static analysis which means it only solves the solution until it reaches equilibrium. So the bottom of the swing would be the equilibrium position which is why you see what you do.

                                          Cheers,

                                          Ian