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Showing content with the highest reputation since 07/11/2019 in Blog Comments

  1. 1 point
    Not sure I understand the wand issue completely. That said, it is very often true that the sensor and servo functions do not need to directly address (code) the physics to achieve a reliable servo action. You can characterize the wand with some regression on the likely variables and use that to generate the input to the servo function. Also, be vary careful screwing with the sensor data in an (often) misguided attempt to filter the data. All too often we see attempts to brutally clip (supposedly) outlier data or shortcut coded filters that generate too much noise. Do the right thing from the start with a proven effective filtering function (sinc?).
  2. 1 point
    The first improvement I’d work on making after replicating the existing system (i.e. sonar sensor for current ride height and servo for actuation only) is improving the algorithm. Specifically, the gearing on the UFO is setup to handle waves as well as possible at a slight top speed cost, but with the electronic system it’s easy to automatically adjust gearing. What you want to try is taking lift off the flap faster when ride height gets too high, adding it back faster when boat gets near/in the water and keeping the flap close to neutral at a constant gearing at your desired ride height. someone has already set this up mechanically in a moth: https://avalonsails.com.au/blog/2018/3/14/latest-update-on-the-bugs-cam. The ride height adjusted gearing should make the boat easier to foil and less likely to ventilate. It can also improve top speed by reducing flap actuation and associated drag when you’re stably foiling at your desired ride height. My second thought is that boat speed sensors will be a pain, because gps will not give accurate boat speed if there’s significant current. That’s why I think you focus on what you can do to improve the system without boat speed as an input before you add the additional sensors. Paddle wheels are out for speed through the water, because they’re a pain and where do you put it. That leaves ultrasonic speed sensors, but they also need to be in the water, so where do you put it. Best place is probably the mainfoil. You’ll definitely need to find a sensor way smaller than what I’ve seen on keelboats and find a faired way of incorporating it. And You’ll need a second prototype mainfoil to incorporate the sensor and fairing, while still having a one-design UFO readily available. Anyway, my two cents is to get started under the assumption you won’t know boat speed and only incorporate boat speed later. improvements can be made without boat speed data for sure. -Nick
  3. 1 point
    I have been thinking about this for a while as well. One of the areas where I have evolved a bit is that I worry about a servo and batteries powerful enough to drive the flap mechanism. Because of that, in my mind practical uses of #1 should be later in the roadmap. It makes sense to start with small simple servo mechanisms that that engage/disengage the wand (your #2) and can control foil rake. A simple mechanism to control wand length (manually or electronically) can also be a winner with modest effort and complexity. I would set all these things up, and provide simple manual control -- as SuperFoiler had, buttons on the tiller extension. There is significant work in making these mechanisms work: reliability, failsafe, etc. This stage of work has, in itself, great value and can stand alone. All the sensor driven work -- GPS, gyro, water distance -- and computer algorithms should be -- IMHO -- second phase.

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