Multiple Missions without GCS

Simon_Exner · November 11, 2020, 5:49pm

Hi,
Using a GCS after testing is complete (so during normal operation) is not an option for me. I am looking to select one of two (or more) missions by a switch on my RC-Transmitter (e.g for a mission that flys regular traffic patterns, i want to be able to switch between eastbound and westbound takeoff/land and pattern direction depending on the wind). Is there any way to do that without using a GCS? I neither found a way to upload multiple missions, nor something like conditional jumps in a mission (to put all missions in one big mission and select them by a specific condition)
Is there any way to accomplish my goal?

iampete · November 11, 2020, 6:02pm

sure, scripting.

This is a example of loading a mission from the SD card:

github.com

ArduPilot/ardupilot/blob/master/libraries/AP_Scripting/examples/mission-load.lua

-- Example of loading a mission from the SD card using Scripting
-- Would be trivial to select a mission based on scripting params or RC switch

local function read_mission(file_name)

  -- Open file
  file = assert(io.open(file_name), 'Could open :' .. file_name)

  -- check header
  assert(string.find(file:read('l'),'QGC WPL 110') == 1, file_name .. ': incorrect format')

  -- clear any existing mission
  assert(mission:clear(), 'Could not clear current mission')

  -- read each line and write to mission
  local item = mavlink_mission_item_int_t()
  local index = 0
  while true do

    local data = {}

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And this is a example of reading a RC switch:

github.com

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

-- example of getting RC input

local scripting_rc_1 = rc:find_channel_for_option(300)
local scripting_rc_2 = rc:find_channel_for_option(301)

function update()
  pwm1 = rc:get_pwm(1)
  pwm2 = rc:get_pwm(2)
  pwm3 = rc:get_pwm(3)
  pwm4 = rc:get_pwm(4)
  gcs:send_text(0, "RCIN 1:" .. tostring(pwm1) .. " 2:" .. tostring(pwm2).. " 3:" .. tostring(pwm3).. " 4:" .. tostring(pwm4))

  -- read normalized input from designated scripting RCx_OPTION
  if scripting_rc_1 then
    gcs:send_text(0, "Scripting in 1:" .. tostring(scripting_rc_1:norm_input()))
  end

  -- read switch input from second designated scripting RCx_OPTION
  if scripting_rc_2 then
    local sw_pos = scripting_rc_2:get_aux_switch_pos()

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Those scripts will only work on 4.1.dev, it should be relatively straight forward to combine to allow loading of a mission based on the switch position.

Simon_Exner · November 11, 2020, 6:06pm

ok, thanks. I will take a look at that. could you quickly explain why 4.1 is necessary? I thought scripting was available since at least 4.0

Notorious7 · November 11, 2020, 6:31pm

Scripting is available on 4.0 stable releases but you need to bind features to lua in order to use them with lua scripting, have a look here https://ardupilot.org/copter/docs/common-lua-scripts.html#how-to-add-new-bindings

Right now, most of the bindings which are available in master i.e. 4.1-dev have not been implemented/added on any stable release, so what you looking to do right now can be done with lua bindings available on 4.1-dev only or you yourself backport the bindings on latest stable release

Simon_Exner · November 11, 2020, 6:34pm

ok, thank you very much. so I will wait for the 4.1 stable release

Notorious7 · November 11, 2020, 6:37pm

It can probably take weeks or few more months for stable 4.1 release, devs can tell more accurately, nowadays using master version isn’t that bad to try out new features

Simon_Exner · November 11, 2020, 6:44pm

well, such info would be nice, but I dont want to nag, the devs are gods anyways
I can wait: summer has just ended and so has gliding season for me.
I dont like tinkering with unfinshed and/or self compiled software for such things. I like tinkering with software in general, but I am not confident enough with my skills to tinker with such safety critical systems

Notorious7 · November 11, 2020, 6:55pm

People generally avoid taking risk with master version, but you just need to take calculated risk, working with latest developments is much more fun, indeed safety is the utmost priority, and there are many kinds of failsafes in place in master (more better ones compared to stable releases) to make sure about the safety of your vehicle still its understandable in cases of planes as they are more fragile and unlike copter where in worst case scenario you can always attach some light rope or strong thread but that cannot be done with planes

Simon_Exner · November 11, 2020, 7:07pm

I get that, but I am using Arduplane to get a particular thing done (autonomus tow plane) I am not at all interested in using it for my regualer planes (there is no reason to do that) So I am actually not interested in “having fun” with the software
So I see no piont in inversting my time and engery into compiling and tinkering with the software myself. I like to do modelflying and bulding in my free time, not programming them