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  • 18th July 2018 at 2:26 pm in reply to: PTO dynamics #1633
    IFP Energies nouvelles
    Competitor

      Hi John,

      I am getting back to you concerning PTO dynamics. A few weeks after your reply, a new version of the model appeared on GitHub with an updated cmd-to-force transfer function. The new transfer function still has a direct transfer term but also shows an oscillating behavior, with a (5%) settling time of about 1s.

      This modeling choice still puzzles me. Has the transfer function been obtained by system identification using experimental data from the real PTO? Would it be possible to study these data to better understand your choice and get prepared to the implementation of our controller?

      Thanks

      Kind regards,

      Paolo

      12th April 2018 at 8:44 am in reply to: Restoring force is shifted up? #1391
      IFP Energies nouvelles
      Competitor

        Thanks, Nathan.

        Cheers,

        Paolo

        10th April 2018 at 12:53 pm in reply to: Restoring force is shifted up? #1388
        IFP Energies nouvelles
        Competitor

          Nathan,

          The WEC-Sim on-line documentation states that “WEC-Sim requires that all hydrodynamic coefficients must be given at the center of gravity for each body”. Could you give me the position of the point used to compute the hydro coefficients in ‘wavestar.out’ and ‘wavestar.h5’, with respect to point A?

          Thanks

          Cheers,

          Paolo

          14th March 2018 at 12:15 pm in reply to: A few questions regarding the Evaluation metric and the wave probes #1355
          IFP Energies nouvelles
          Competitor

            Hi Nathan,

            I might be mistaken, but I think that the new advanced feature providing up to three numerical wave gauges has not been included in the master branch of WEC-Sim. It follows that the latest version of WECCCOMP cannot run (as the new property ‘waves.wavegauge<i>loc’ is unknown). The new feature is included in the ‘gh-pages’ branch, though.

            Cheers,

            Paolino Tona
            IFPEN Team

            12th January 2018 at 1:31 pm in reply to: Rotary controller inputs #1334
            IFP Energies nouvelles
            Competitor

              An update with what I have found digging in the code:

              – The control input ‘motor_pos_rot’ actually gives the float angular position (the relative pitch displacement to be more precise)
              – The control input ‘float_accel_rot’ is not the float pitch acceleration. There is an conversion step in block ‘lin2rot conversion’ block, which is unnecessary as its input ‘float_accel’ is already the angular acceleration float. In my opinion, this is a bug which should be corrected.

              Could you please confirm/infirm?

              Thanks

              Best regards,

              Paolino Tona
              IFPEN Team

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