Booster Motor Scale Change Using Rc Switch?

ton999 · June 10, 2020, 1:09pm

Dear gentlemen, based on current firmware (of quadcopter) we can change scale of booster motor between 1-5 on the parameter table.
Is it possible to change this Scale number of booster motor using one of the Rc switch or using one of the Rc channel… Anybody can help???
The purpose is to adjust thrust of the booster motor during flying, to get optimum value in real time.

Thank you

iampete · June 10, 2020, 1:44pm

Not possible on copter 4.0 You could do it on dev using scripting.

ton999 · June 10, 2020, 1:53pm

Hi Peter, thank you for your quick response. To my knowledge you are the master in this area. Could you help me, how to do it ? Is it difficult?? Is it a major changes? I am very keen to have this function. I believe this function is very very important for a multirotor. Your help is highly appreciated.
Best regard.
Tony

iampete · June 10, 2020, 2:04pm

This is a example of getting RC_IN

github.com

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

-- example of getting RC input


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))
  return update, 1000 -- reschedules the loop
end

return update()

and this is setting params

github.com

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

-- This script is a test of param set and get
local count = 0

function update() -- this is the loop which periodically runs

  -- get and print all the scripting parameters
  local value = param:get('SCR_ENABLE')
  if value then
    gcs:send_text(6, string.format('LUA: SCR_ENABLE: %i',value))
  else
    gcs:send_text(6, 'LUA: get SCR_ENABLE failed')
  end
  value = param:get('SCR_VM_I_COUNT')
  if value then
    gcs:send_text(6, string.format('LUA: SCR_VM_I_COUNT: %i',value))
  else
    gcs:send_text(6, 'LUA: get SCR_VM_I_COUNT failed')
  end
  value = param:get('SCR_HEAP_SIZE')
  if value then

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Should be quite straignt forward to combine the two to change a pram based on the pwm of a rc input.

Note that it is a bad idea to set params at a high rate, this is because it has to search through all the params each time to find the matching string. 1hz or less is probably OK.

On you could also completely re-implement the boost functionality within scripting. You could read in all the motor outputs, take the average and output that on a new channel.

ton999 · June 10, 2020, 3:04pm

Wow thank you Peter for showing me the sample script. However I am not software engineer. I understand the concept, but I can not do the scripting myself. Should I do a PR for this function?
Thank you.
Tony