Plane follow script Applet by timtuxworth · Pull Request #28546 · ArduPilot/ardupilot

timtuxworth · 2024-11-07T11:28:22Z

This creates a new Lua Script applet that implements "plane follow" - a fixed wing follow/chase functionality that runs in guided mode. The code uses the core AP_Follow library functionality and therefore uses most of the documented FOLL_ parameters that are used in Copter and Rover FOLLOW mode.

I've also included 3 Lua modules that are used by the script but might also be useful to others.

speedpid.lua - A PID controller extracted/generalized from plane_aerobatics
mavlink_command_int.Lua - allows sending MAVlink command_int messages to another vehicle
mavlink_attitude - a receiver for MAVlink ATTITUDE messages sent by another vehicle.

This PR depends on
#28526 - this has now been included into this PR
ArduPilot/mavlink#372 - this has been merged
#28527 - this has been merged

timtuxworth · 2024-11-09T09:53:17Z

Could you take a look @peterbarker and @tridge ?

timtuxworth · 2024-11-09T13:08:29Z

I wonder if you'd be able to take a look at my Lua @yuri-rage - any suggestions appreciated.

yuri-rage · 2024-11-09T16:48:08Z

I wonder if you'd be able to take a look at my Lua @yuri-rage - any suggestions appreciated.

I'd be happy to take a look, Tim, but I have some external commitments upcoming that may prevent me from diving in right away. Please remind me either here, Discuss, or Discord if I don't reply in a week.

IamPete1 · 2025-03-31T21:59:43Z

    next_WP_loc = loc;

    // used to control FBW and limit the rate of climb
+    // cannot be applied in Guided as this prevents the guided set altitude from working correctly


Why is this?

I guess it's because this code assumes that GUIDED is always running in "location" sub-mode (i.e. flying towards a location), but my follow code needs to switch between "location" sub-mode and "heading" sub mode. This line prevents the target altitude being reset when switching between sub-modes.

I think this would prevent a simple mode change to GUIDED from locking the current alt

timtuxworth

Implemented changes from the Dev call on 31 March 2025

tridge · 2025-03-31T23:40:35Z

        _target_location.lng = packet.lon;

        // select altitude source based on FOLL_ALT_TYPE param 
+#if APM_BUILD_TYPE(APM_BUILD_ArduPlane)


i think this should be available on copter

tridge · 2025-04-07T23:41:28Z

    next_WP_loc = loc;

    // used to control FBW and limit the rate of climb
+    // cannot be applied in Guided as this prevents the guided set altitude from working correctly


I think this would prevent a simple mode change to GUIDED from locking the current alt

tridge · 2025-04-07T23:42:57Z

    // check for timeout
-    if ((_last_heading_update_ms == 0) || (AP_HAL::millis() - _last_heading_update_ms > AP_FOLLOW_TIMEOUT_MS)) {
+    if ((_last_heading_update_ms == 0) || (AP_HAL::millis() - _last_heading_update_ms > (uint32_t)_timeout_ms)) {
+        gcs().send_text(MAV_SEVERITY_NOTICE, "gthd timeout %d", (int)(AP_HAL::millis() - _last_location_update_ms));


could flood the link with msgs?

IamPete1 · 2025-04-07T23:40:36Z

    AP_Follow follow;
 #endif

+    AP_Int32        guided_timeout;


AP_Float please.

IamPete1 · 2025-04-07T23:47:37Z

+    AP_Enum<Location::AltFrame>    _alt_type;          // altitude source for follow mode
    AC_P        _p_pos;             // position error P controller
    AP_Int16    _options;           // options for mount behaviour follow mode
+    AP_Int32    _timeout_ms;        // position estimate timeout after x milliseconds


AP_Float and update comment for seconds.

IamPete1 · 2025-04-07T23:52:27Z

            return false;
        }
+        // ignore message if we already received a more recent one
+        if(_target_location_last_time_boot_ms != 0 && packet.time_boot_ms <= _target_location_last_time_boot_ms ) {


What happens if the follow target vehicle is rebooted? Its boot time will go backwards so it will be ignored. Maybe if the time is more than 5 or 10 seconds in the past it would reset the boot time.

tridge · 2025-04-07T23:53:54Z

+   local xy_dist = follow:get_distance_to_target() -- this value is set by get_target_dist_and_vel_ned() - why do I have to know this?
+   local target_heading = follow:get_target_heading_deg()
+*/
+bool AP_Follow::get_target_info(Vector3f &dist_ned, Vector3f &dist_with_offs,


I find it odd to be fetching both with and without the offset, why would a consumer want both?

I think we need to fix the API so you don't need to call function A in order to get the correct value for function B

timtuxworth · 2025-08-14T17:09:02Z

Replaced by #30654

IamPete1 reviewed Nov 7, 2024

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Comment thread libraries/AP_Scripting/modules/speedpi.lua Outdated

timtuxworth force-pushed the pr-plane-follow-script branch 5 times, most recently from b2021a5 to c6bec54 Compare November 8, 2024 10:55

timtuxworth force-pushed the pr-plane-follow-script branch from c6bec54 to a85ee8f Compare November 9, 2024 10:00

timtuxworth force-pushed the pr-plane-follow-script branch from a85ee8f to b9de7f9 Compare November 15, 2024 04:47

timtuxworth force-pushed the pr-plane-follow-script branch from b9de7f9 to 3cbe60d Compare November 28, 2024 19:14

timtuxworth force-pushed the pr-plane-follow-script branch 2 times, most recently from db44c23 to 8910d83 Compare December 21, 2024 20:50

timtuxworth requested review from tpwrules and tridge December 27, 2024 03:45

timtuxworth force-pushed the pr-plane-follow-script branch 2 times, most recently from 52d0f53 to 2183684 Compare January 24, 2025 22:31

timtuxworth force-pushed the pr-plane-follow-script branch 2 times, most recently from 2821e85 to 3a0b2c3 Compare February 17, 2025 23:39

timtuxworth force-pushed the pr-plane-follow-script branch 4 times, most recently from 9e6a6a8 to 7b22a30 Compare March 16, 2025 19:00

timtuxworth force-pushed the pr-plane-follow-script branch 2 times, most recently from b0db2e8 to 8b99bef Compare March 20, 2025 20:49

timtuxworth added the DevCallTopic label Mar 31, 2025

timtuxworth force-pushed the pr-plane-follow-script branch 2 times, most recently from 8f59dc2 to 47f44b2 Compare March 31, 2025 21:10

IamPete1 reviewed Mar 31, 2025

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Hwurzburg added the WikiNeeded needs wiki update label Mar 31, 2025

CraigElder removed the DevCallTopic label Mar 31, 2025

peterbarker reviewed Mar 31, 2025

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Comment thread libraries/AP_Follow/AP_Follow.h Outdated

timtuxworth force-pushed the pr-plane-follow-script branch from 181025f to 07a0e56 Compare April 7, 2025 01:23

timtuxworth commented Apr 7, 2025

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timtuxworth added the DevCallTopic label Apr 7, 2025

CraigElder removed the DevCallTopic label Apr 7, 2025

tridge requested changes Apr 7, 2025

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IamPete1 reviewed Apr 7, 2025

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tridge requested changes Apr 7, 2025

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timtuxworth mentioned this pull request Apr 23, 2025

AP_Follow: change to using position-from-origin internally #27250

Merged

timtuxworth force-pushed the pr-plane-follow-script branch from 07a0e56 to be40b54 Compare April 24, 2025 04:47

timtuxworth added 2 commits April 26, 2025 10:43

AP_Follow: changes to support scripted plane follow

ab9c623

ArduPlane: changes to support scripted plane follow

a5c65aa

timtuxworth force-pushed the pr-plane-follow-script branch 2 times, most recently from eccc87a to f4065aa Compare April 26, 2025 04:32

AP_Scripting: scripted plane follow

27ccc36

timtuxworth force-pushed the pr-plane-follow-script branch from f4065aa to 27ccc36 Compare April 26, 2025 08:30

timtuxworth closed this Aug 14, 2025

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