Adjusting reported Latent Data fields for electrohydraulic PTO #162
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hamilton8415
changed the title
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electro_hydraulic: Adding enough fields to see the energy balance. For instance, considering the hydraulic portion of this, energy leaving the hydraulic system as a loss is a positive value. Supplied hydraulic power is then negative and represents power coming into the hydraulic system from the piston (-359.51327W), Because at the moment of the example data the electrics are acting as a generator, the shaft power is taking energy out of the hydraulic portion, and so is listed as a postive mechanical power (321.62192 W). Since there is no flow through the relief valve at these low speeds, the only loss in this portion is the combined volumetric and mechanical hydraulic loss (37.90059 W). And, -359.5132+321.62192+37.900593 sums to zero, as it should. :) Next up, the electrical side and it's slightly more complicated loss model... |
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Similarily, with the relief valve operating and adding an additional loss. electro_hydraulic: -8500.501+6908.771+1085.208+506.645 = 0.123 The small total error is a result of the numerical solution being de-tuned to not demand sub-watt accuracy in a 10kW system, speeds computation... |
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And finally, with a winding current specification that causes the system to run in motoring mode, the shaft power becomes negative (energy flowing into hydraulic system), the supplied hydraulic power" becomes positive (energy flowing from the hydraulic system to the piston, and the hydraulic motors remain, alas, positive as expected. But the powers still sum to zero: 643.229-715.63+72.38 = -0.021 electro_hydraulic: |
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I believe I have this completed. The resulting message is below and everything is summing up as it should. There are some sign conventions here that are a bit tricky, I think I will need to add some description of all of this in the documentation site, along with a tutorial. But for now, I think this is done from my point of view and we should merge it into andermi/latent_data after review. Happy to consider other fields of interest... And, almost certainly some linter work to do... electro_hydraulic: |
needs osrf/mbari_wec_utils#55
Changing the reported latent data fields for the electrohydraulic PTO. So far this adds the shaft mechanical power, and I have am going to work through the rest and make sure it all makes sense.
While I'm here I've eliminated the pto_loss structure, as it wasn't needed on the ECM, or at all now that the latent data structures exist.
Also, to do this, it will make sense to move a number of items into the numerical solution functor class variables, to avoid re-computing things un-neccessarily. I need to review why some of these items need to be marked mutable...