Arduboat wave measurement?

uchiha · March 2, 2022, 12:29pm

Has anyone here on this forum managed to use Pixhawks gyroscope and accelerometer to measure waves?

geofrancis · March 2, 2022, 4:41pm

Unfortunately, no, I have talked about it before and an issue has been opened.

There is a lot of work that could be done with water state estimations but It’s something that would need high resolution sensor information so its not something I could get done in lua, it would have to be implemented internally on the firmware.

I think you would need to use a combination of a high precision gps like RTK and accelerometer information to get enough information

uchiha · March 2, 2022, 4:52pm

What a shame. Guess I will have to use an arduino

iampete · March 2, 2022, 5:06pm

No reason you cant do it in lua, it will run just as fast as the main firmware. We do have wave simulation in the boat simulator. Its certainly possible.

uchiha · March 2, 2022, 10:11pm

Can we display information with lua scripting? Where does the output show?

iampete · March 2, 2022, 10:58pm

Yes, you can log directly to data flash, send messages or send numbers. The numbers will appear in mission planners quick tab and in the tunning graphs.

See the simple loop eaxample:

github.com

ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/examples/simple_loop.lua

-- This script is an example of saying hello.  A lot.
-- Pick a random number to send back
local number = math.random()

function update() -- this is the loop which periodically runs
  gcs:send_text(0, "hello, world") -- send the traditional message

  gcs:send_named_float('Lua Float',number) -- send a value
  number = number +  math.random() -- change the value

  return update, 1000 -- reschedules the loop
end

return update() -- run immediately before starting to reschedule

uchiha · March 2, 2022, 11:44pm

Awesome. Does it work for QGroundControl?

An example on how to measure anything with Pixhawk would be extremely helpful. I have no idea where to start. How to get data from the IMU and accelerometer and use it to calculate wave height, velocity etc.

geofrancis · March 3, 2022, 9:52am

is there any way of pulling altitude data from rover? I thought it was all disabled.

iampete · March 3, 2022, 7:49pm

all the attitude info is still there, we still run the full EKF like on copter and plane. We just do not use it for navigation.