search

osrf / mbari_wec_gz

Simulation of wave energy harvesting buoy
Apache License 2.0
18 stars 2 forks source link

Add wave body total power to latent data #165

Closed andermi closed 12 months ago

andermi commented 1 year ago

requires osrf/mbari_wec_utils#57

hamilton8415 commented 1 year ago

Looks good, it's hard to verify that the powers are correct, and one can see that the leading order term of the excitation force is the opposite of the buoyancy force, as it should be in this linear theory. Makes it a bit hard for either one to have meaning without the other, but I think we should leave it this way as that's usually how these things are represented.

We may want to add the position and velocity of the buoy to this message, i.e. w_Pose_p for the position, and w_xdot_p and w_omega_p for the velocities. I think that could be useful information for a number of things.

Also, since we're here, it'd be great to include the local incident wave height that's being used to compute the exciting force. Looks like I did some trickery so that the exciting force computation figures out what that is on it's own, so there isn't an explicit assignment. Looking at that it's computed as " _IncWave->eta(0, 0, t);" in the wave-exciting force code, and we have that incident wave object so should be easy to get it. Note that it has to be called at x=0,y=0. This isn't very satisfying, but how it has to be, it basically means the origin of the wave-field is moving around with the buoy, and a point to discuss related to WecSIM, I am not sure how they handle the issue but it could be related to the slight phase difference we see when comparing results.

Anyway, I am also happy to add these last features if desired.

hamilton8415 commented 1 year ago

Right, and immediately after hitting send, I remember that we already have the capability to show the wave-height data. Showing that at the buoy origin should do the trick, so maybe we can leave it at that.

andermi commented 1 year ago

I added pose: position, orientation twist: linear/angular velocities

andermi commented 1 year ago

and like you said, we have the wave height at the buoy position being reported in latent data by default

andermi commented 12 months ago

should I do anything with the WaterplaneOrigin (b_Pose_p) ? it's hardcoded to (0.0, 0.0, 2.45) above the buoy link origin

hamilton8415 commented 12 months ago

I don't think anything is neccessary, that location is where the buoyancy force balances the weight. If it's off, there's no big effect other than in calm water there's a steady-state buoy dispaclement to account for the difference.

andermi commented 12 months ago

I think this is ready to go then