Is it possible to change waypoint speed and camera mount pitch?

ardupilot.td · September 23, 2020, 5:20pm

Hi,
I need to change waypoint speed and camera mount pitch during a mission. The simplest way seems to be a LUA script. Do the necessary bindings exist or is it possible to send a mavlink command?

Thank you,
Tobias

iampete · September 23, 2020, 5:24pm

You can do the waypoint speed by changing the param from the lua script.

Mount pitch is a little harder, you could add a binding to do that. If its servo controller you can change the servo output from the script.

ardupilot.td · September 23, 2020, 5:57pm

Thank you very much!

I use a Basecam setup as descriped here:
https://ardupilot.org/copter/docs/common-simplebgc-gimbal.html

I guess it is not possible to control without adding bindings (I do not know yet how to do that)?

But I think you guided me to the right approach.
I will try to modify a mission after it was loaded and add the waypoint speed and do mount control items. I think that should work.

github.com

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

-- mission editing demo lua script.
-- by Buzz 2020
current_pos = nil
home = 0
a = {}
demostage = 0 
eventcounter = 0

function update () -- periodic function that will be called
    current_pos = ahrs:get_position()

  -- adds new/extra mission item at the end by copying the last one and modifying it
  -- get number of last mission item
  wp_num = mission:num_commands()-1
  --get last item from mission
  m = mission:get_item(wp_num) 
  -- get first item from mission
  m1 = mission:get_item(1) 

  if wp_num >  0 then

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iampete · September 23, 2020, 6:14pm

You will need new bindings for the gimbal over serial.

Why not just change the WPNAV_SPEED param? Much easier script.

ardupilot.td · September 23, 2020, 6:56pm

Yes, you are right.

This would mean I need to add a pull request for the new bindings? I think that is beyond my current knowledge.

I guess the method is this one:

void set_angle_targets(uint8_t instance, float roll, float tilt, float pan);

in line 121 in /libraries/AP_Mount/AP_Mount.h

Then I open a new section in /AP_Scripting/generator/description/bindings.desc

include AP_Mount/AP_Mount.h
singleton AP_Mount method set_angle_targets boolean uint8_t instance, float -90 90 , float -90 90, float -180 180

Even if that is right, the next step is beyond my unterstanding.

Open a command line prompt and cd to the /libraries/AP_Scripting/generator directory and type “make run”

Since that is a method which is interesting for many people it might be useful to implement it?

iampete · September 23, 2020, 7:24pm

Yes, A PR would be great, you can always open a draft and ask for advice

Your binding is nearly correct, not much point in using the version with a instance as AP_MOUNT_MAX_INSTANCES is 1. This builds on master (but I have not tested in any way):

include AP_Mount/AP_Mount.h
singleton AP_Mount alias mount
singleton AP_Mount method set_angle_targets void float -90 90 float -90 90 float -180 180

You should then be able to use in lua with:

mount:set_angle_targets(roll, pitch, yaw)

No need to manually run the generator anymore, it is run automatically when you build the main code.

ardupilot.td · September 23, 2020, 7:52pm

Thank you very much! I have tried to make a pull request. First time ever. I hope that is right.