It's been about six months since I've made any progress with pylon tracking data, so it seemed like a good time to make my ski partners suffer through another day on the lake with computers, wires, and sensors (they are very kind! @Gloersen
). The approach I took before was to put strain gauges directly on the pylon and then extract load magnitude and load direction from pylon deflection. It worked pretty well, except when the load was too low the signal to noise ratio got pretty rough. So, I modified the setup and am now taking load data directly in-line with the rope and rope angle directly as well with a little swivel tracker. I'm pretty happy with the results. The swivel tracker had a few degrees of mechanical play in it, so I need to snug that up, but the data seems good enough to share.
Here's some data graphed out (slightly low pass filtered).
There is a lot you can do with this data; I find the hardest thing is to figure out how best to present it. It seems like a good place to start is simply to plot out the physical handle path, so here you go...
Keep in mind the few degrees of slop in the swivel hardware, which explains why it seems to come up slightly short at the turn balls. I tried to scale the graph to the correct aspect ratio to make it visually correct. It's pretty much a saw tooth pattern. It will be interesting to overlay different line lengths and speeds.
I had a few requests the last time around for a copy of the raw data, which I pretty much ignored (sorry about that). The data was just not clean enough at the time to really let it out. It's still not where I want it, however it's probably good enough that if anyone wants a copy just send me a message. I'd be happy to contribute to the wasting of free time.