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About oracid

  • Birthday 08/01/1953

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  1. In this video, I show how easy it is to use RC servo in Lego environment. Note that the axis of a joint must never be directly attached to the axis of the servo to avoid lateral forces.
  2. Thank you all. It is not so easy to couple RC servo to Lego. That is why I used chain at 4'25". Thank you to give the links in Thingiverse.
  3. Thank you so much @Splat I will test this software very closely. I need something like this. I knew this video, it is very good.
  4. @Davidz90, thank you for your diagrams. That make me look for a video and I found this, https://youtu.be/8AothYl4evU . If you are accurate all the legs move, but only one gets up. At the end, I think it's the same walk as the horse. Look at this very good video (at 2'16" for quick), <Your link is not good.>
  5. I don't know much about walker, that is why I investigate, but I am not sure of that. As I can see, this one move 2 legs at the same time, http://www.algodoo.com/algobox/details.php?id=176820 May be you think about camel walk. Can you show me an exemple ? I am very interested. I don't know yet which linkage I will use. The Jansen linkage has bottom flat line of course, it has too a square in the middle and the pivot is in one of the square corner, the actuator is aside too. Somes have suppress the triangles hypotenuses. Klann walker is flat too, even if it is not very flat in my video. Here an example, https://youtu.be/WsRVu8BoSN4 The both, Klann and Chebyshev linkages have less pieces than Jansen. I would like very much to make my own bottom flat line. But is it sure that is it absolutely necessary ? Do you have any arguments about that ?
  6. In this video, I show you how to make a tank with an Arduino board and 360° RC servos.
  7. Here are my topics to move. Thank you : https://www.eurobricks.com/forum/index.php?/forums/topic/168046-quadruped-kinematic-workbench/ https://www.eurobricks.com/forum/index.php?/forums/topic/167863-ev3-big-toy-quadruped-robot/ https://www.eurobricks.com/forum/index.php?/forums/topic/163763-ev3-toy-quadruped/ https://www.eurobricks.com/forum/index.php?/forums/topic/161527-tank-climber-55cm-new-frame/ https://www.eurobricks.com/forum/index.php?/forums/topic/158504-smallest-tank-climber/ https://www.eurobricks.com/forum/index.php?/forums/topic/156061-variable-geometry-tank-climber/ https://www.eurobricks.com/forum/index.php?/forums/topic/139522-ev3-big-and-light-tank-climber-12/ https://www.eurobricks.com/forum/index.php?/forums/topic/119844-lego-tank-climber-test/ https://www.eurobricks.com/forum/index.php?/forums/topic/122127-lego-–-funny-little-tank-in-a-mars-field-7/ https://www.eurobricks.com/forum/index.php?/forums/topic/117220-lego-ev3-green-wheels-robot-base-with-xl-motors/ https://www.eurobricks.com/forum/index.php?/forums/topic/115732-moc-delta-rover/ https://www.eurobricks.com/forum/index.php?/forums/topic/114392-lego-big-is-a-rover/ https://www.eurobricks.com/forum/index.php?/forums/topic/110044-lego-porcupine-rover/
  8. oracid

    New Mindstorms Forum

    This new forum is a very good idea. Thank you. I am very interesting in robotic, and I use as well EV3 and PF for testing. As I did not know about this new forum, I have just posted a new topic about quadruped kinematic, here If you think the place of this topic is here, of course you can move it.
  9. With Big Toy, https://www.eurobricks.com/forum/index.php?/forums/topic/167863-ev3-big-toy-quadruped-robot/, I realized very quickly that the kinematic was largely part related to the attachment points of the legs. To progress in my quadruped project, I had to choose between the different existing kinematics, such as Jansen, Klann, Hoecken, Chebyshev etc. But how to choose without testing? To make as many quadrupeds as there are linkages was unrealistic. In addition each linkage has a variation to infinity, as soon as you change any piece. So I tried with a software like Algodoo, http://www.algodoo.com/, which is absolutely extraordinary, but after a few days, I considered that it was very tedious to modify the least element. So I had the idea to make a Lego workbench with which I will use my brain and my hands. And even if my brain is not exceptional, I noticed that I was going much faster to change the structure of the pieces. When I say faster, I mean 50 times, or 100 times, faster. In this video, I show a simple mechanism, based on the parallelogram. This parallelogram has a peculiarity, that it looks like the letter "d". The activation / rotation point being elevated relative to the fixed pivot point. With reference to the parallelogram and the letter "d", I named this mechanism "d #". As you can see, in a few seconds, I show that changing the location of the pivot point has a strong impact on the kinematics of the end of the leg.
  10. No, no ! I have been interested in tanks for 3 years. I guess it will last longer for quadrupeds. In any case, I work about it.
  11. Thank you for your encouragement.
  12. Here is my last quadruped, Big Toy. With this quadruped, I wanted to show what was the maximum size I could achieve with the power of Lego servos. As you can see, if it goes well in a straight line, its orientation is not very efficient.
  13. May be, something like this can help too : https://www.ebay.fr/itm/Crochet-hooks-needles-8pcs-set-0-6mm-1-75mm-Fine-hook-yarn-Knitting-small/162512094916?hash=item25d679c6c4:m:mVAXBbszUp60NzQJwNfG5mQ