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Roll and Pitch
#1
Hello everybody
I have just ordered Tinypilot and look forward to install it on my boat.
In the meanwhile I'm wondering about some issues.
One of this is:
does pypilot use roll and pitch values to evaluate correction to rudder or it bases its corrections only to compass?

Regards,
Francesco
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#2
The main corrections are based on compass and yaw gyro. The accelerometers as well as compass are used to compensate gyros from drift. So in this way, it does use the accelerometers.

If you are asking if it makes corrections from pitching or rolling motion... I did experiment with this in the ocean and did not find useful results. I think it is mostly useful in gusting winds to react to roll from a wind gust, and I have plans to support this in the "wind pilot" which is a pilot that does not rely on the compass at all, instead it directly reacts to wind sensors... So steering a gps course on the wind pilot, it will follow the wind shifts to some extent.
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#3
(2019-05-27, 11:59 PM)seandepagnier Wrote: ... I think it is mostly useful in gusting winds to react to roll from a wind gust...

Thanks for reply Sean,
Yes, this exactly what I intended, the ability to 'preview' sudden yaw under gusts by evaluating roll values.
Are You planning to introduce a fifth autopilot mode or it will be a brand new product?
Regards
Francesco
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#4
The newer version of pypilot introduces multiple "pilots" you can switch between.

This allows easy experimentation of different control algorithms. As for the gusting wind, it is unclear if it should use the roll gyro, or the wind speed (if available) or even the heel angle.

Going by heel angle would allow it to point closer in higher wind which can be useful (at least on a monohull) where going by roll gyro would allow it to react to gusts. Most likely it would be a combination of the two, like the P and D elements in the filter, but the best way to do it is unclear. Also the conditions really change how you might want this to work. I will be experimenting with this when I sail again in 2 weeks.
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#5
I am searching for recent findings about behavior in gust: what is thinking now? Smile or is there some reference to find it.

My boat reacts a lot to gust so topic is interesting!

I am in process to update auto pilot and pypilot sounds very interesting. I assume that it would control boat better compared to only compass feedback - yaw gyro would make it faster?

"Point closer" and "react to gust" modes are also great interest! When I saw that there is just one dimension in gain parameters, it sounds that roll and pitch play minor role compared to yaw.
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#6
what you are describing as far as reacting to gusts is not implemented in a proven way although I have done some experimenting

It may or may not require wind sensors and it is easy to add this but end up finding it makes the pilot worse at other times.

The main feedback is from the gyro regardless of anything, but adding logic to help surf waves is something interesting to consider.
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