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Everything posted by oracid

  1. Here is a new mechanism that looks more like a real quadruped leg. In this video, I show that a parallelogram with an extension can be considered as a simple parallelogram. This greatly simplifies the calculations.
  2. In this video, I show a quadruped leg based on parallelogram linkage. Usually, a 4 bars linkage has 2 sides consecutively egal , and the 2 opposit sides egal too. You can see it here : https://www.eurobricks.com/forum/index.php?/forums/topic/175138-4-bars-linkage-with-parallelograms-actuators-for-quadruped/ This is too a 4 bars linkage, but with parallelogram frame.
  3. My goal here is to provide a big vehicle for some robotic application. - length 75cm - width 47cm - height 28cm - wheels 27cm - weight 1,750kg
  4. oracid

    Lego - BIG is a rover

    Hi. Here some pictures and links those I hope they will help you. The wheel diameter is 27cm. Each yellow bush are separated with soft silicon tube. https://www.bricklink.com/v2/catalog/catalogitem.page?P=32034&idColor=86#T=C&C=86 https://www.bricklink.com/v2/catalog/catalogitem.page?P=10288&idColor=120#T=C&C=120 https://www.bricklink.com/v2/catalog/catalogitem.page?P=6538c#T=C https://www.bricklink.com/v2/catalog/catalogitem.page?P=4265c#T=C https://www.bricklink.com/v2/catalog/catalogitem.page?P=43093#T=C
  5. What you say is funny because at the beginning I started to build your dodecahedron. Then on each big pentagon, I built a little pentagon connected to each vertex of each big pentagon with an axle. Then I have suppressed the side (axles) of the big pentagons. And the result is the sphere I made. Hope you understand what I say. Not easy to explain. Livio Zefiro wrote a comment.
  6. I use to make topics in the Theme "LEGO Mindstorms and Robotics" but in this case, I thought that this could interest other people. In this new video, I show how to make a big Lego sphere. It is a kind of grail which, to my knowledge, has never been resolved in Lego, except with bricks. Some will say that the axes are arched and that consequently the solution is not admissible. Too bad for them ! This sphere could be used for an inverted Self Balancing or as a fairing for a drone. It was this latter possibility that inspired me. I think my solution is not quite a soccer ball. The soccer ball, I believe, is based on 3 pentagons with one hexagon in the middle, or 5 hexagons and one pentagon in the middle. Which amounts to the same. While in my solution, we do have 5 hexagons and a pentagon in the middle, but we don't have 3 pentagons and a hexagon in the middle. To tell the truth, I didn't do it on purpose. It would surprise me a lot that I could innovate in this area, but who knows, this may interest some tiler ...
  7. I sent a mail to the owner. Thank you anyway.
  8. Thanks all. I don't know Kragle, but yes, we can stick. Personally it doesn't bother me. This is a great link ! Thank you. Is it your blog ? Do you mind if I put it in my video description ?
  9. Thank you for the link. So, I understand that my sphere is not an icosahedron.
  10. 4BQ-1 is my first new quadruped for this new 2020. Characteristics : - weight, 785g - length, 33cm - width, 26cm - Arduino Uno - Shield Uno R3 V5.0 - 8 servos SG90 - alim HENGE UBEC 5V - 6V - 7.4V - 12A - battery 2S - boom stopper (fuse) Don't hesitate to ask information.
  11. Thank you Jim. I did as you said.
  12. Good work ! I use this : https://fr.aliexpress.com/item/32868911434.html?spm=a2g0s.9042311.0.0.27426c37iJLips
  13. What is the voltage of the EV3 output port ? In this video, I show you the answer. I was wrong ! It is always better to measure. In this page, you have all the technical links about EV3, https://education.lego.com/en-us/support/mindstorms-ev3/developer-kits
  14. In this video I evaluate the torque of a scissors and 4 bars linkages for quadruped. In both mechanisms, the servo arms are the same size. In the 4 bars, the amplitude of the movement is approximately 3cm, while in the scissors, the amplitude is approximately 12cm. We can consider that the scissors is a 4 bars duplicated 4 times with an amplitude of 3cm multiplied by the number of modules, i.e. 4.The basic module should therefore have a strength of 60x4 = 240g. What we gain in amplitude and speed, we lose in torque, but this does not means the scissors linkage is not good.
  15. Thank you. I take this opportunity to thank you too for all of your work which inspired me a lot.
  16. I will be very pleased if you have a look to my last video in which I show my new linkage with 4 bars.
  17. In this video I show how it can be used a Scissors Linkage for Quadruped legs.
  18. oracid

    P&P the Polish and Play Robot

    So good ! What about the code ?
  19. oracid

    The Robot Solving Maze

    I would only say one thing, "bravo" !
  20. oracid


    I am pleased to show you my last video about a new quadruped based on 5 bars linkage.