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    Joint issues....

    Scheduled Pinned Locked Moved SketchyPhysics
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    • V Offline
      Valkrist
      last edited by

      Ok, I had a lot of stuff here, but I'm editing it out. I started from scratch, and now the cylinders I made are ALL acting as if they are static, but none of them are. I'll post the file if I can to show what I mean. I want the two front wheels to drive forward and backward, so that they will control turning as well as drive. The third wheel is just a free turning caster wheel. I can't seem to get this put together without something being permanently frozen in place.


      Here it is without joints or groups, why are the cylinders static when simulated?

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      • H Offline
        hpnisse
        last edited by

        Hello.

        The biggest problem in the model is that it´s to small. When objects are to small the physics won´t work.
        But if you scale it up two or three times the physics will work, and the physics joints will work correct when you add them.

        I downloaded the model and change it, scale the vehicle up and add physics joints.
        The script o drive the vehicle is in the "main body".

        Robot Design.skp

        Hope this is what you ask about, sorry for my bad english.

        You drive with the arrow keys.

        ` /hpnisse`
        ` Windows 7 U -Sketchup 8 -SketchyPhysics 3.2-Dec2 - from Sweden`

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        • V Offline
          Valkrist
          last edited by

          Oh, wow! Thanks so much for that. I didn't think the size would be an issue like it was. I just made the model to scale and figured it would work. Now I can really start planning and adjusting my design. Thank you, again!

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          • V Offline
            Valkrist
            last edited by

            Ok, so with the problem figured out I started over with a more detailed model. I have everything set up fine, everything works like it should I added some large hidden primitives that are set to ignore to stiffen up the caster wheel. That worked great. Now I just need some tips on how to make this simulation more accurate. The one hpnisse showed me worked great, it was very smooth. I know that one was scripted, I don't know much about scripting. I just have the left wheel's hinge set to joyLY and the right hinge set to joyRX as controllers.


            Robot Design.skp

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            • H Offline
              hpnisse
              last edited by

              Good that I help you a little bit.
              But what do you mean by "more accurate" ??? maybe I could help you more`!

              ` /hpnisse`
              ` Windows 7 U -Sketchup 8 -SketchyPhysics 3.2-Dec2 - from Sweden`

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              • V Offline
                Valkrist
                last edited by

                I actually fixed it already. Thank you for responding though. The wheels were acting strange because they were cylinders. I changed the physics shape to sphere and everything got much smoother.

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                • H Offline
                  hpnisse
                  last edited by

                  Funny that you fix it by yourself 😛
                  The best way to learn something on computer is to click on everything you see 😄

                  /hpnisse

                  ` /hpnisse`
                  ` Windows 7 U -Sketchup 8 -SketchyPhysics 3.2-Dec2 - from Sweden`

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