• Marten de Groot posted an update 1 year, 2 months ago

    Today I’ve printed a first updated FingerTest plate, including a spring which I’m using as a mechanical Servo-Safer.
    See pictures….
    And tomorrow I hope to test the new 2.5kg servo’s, this depends of the servo’s will be delivered :-)
    I can’t wait….

    • Hello Marten,
      Very nice module for a Finger Starter!!!
      There is no doubt that the servo of 2,5kg will work because even a small SG92R works. With the Finger Starter there isn’t much friction. But such servo will burn for sure if used in the hand. The friction is far greater in many ways in the hand, that is the reason even a MG996 of 12kg Torque is barely enough to avoid heating up. But this is a test device anyway. :)
      Spring added as in your video doesn’t give the best results in the hand, (I have tested it over a year long). Again this is due to high friction requiring high torque. It’s working better as a tensioner instead because the maximum extention of the traction is definite:

      http://inmoov.fr/wp-content/uploads/2013/09/InMoovTensioner1-300×225.jpg

      • Hi Gaël,

        The spring main function is to safe the servo mechanical (there is no direct blocking anymore).
        And including my servo pulley’s, the finger “close position” gets a smaller arm length !
        So this safes a lot of energy use from the servo, when the finger is in his “close position” :-)
        I’m almost sure this spring setup is enough to hold a softball or something like that.
        The servo always go’s to his maximum “close position” to get the full grip to the object.

        Why I’m thinking (and hoping) that a 2.5kg servo is enough, is because the springs which I’m using don’t need more pull energy.

        I hope to show this soon, first I will need the new servo’s :-)