Arduplane Follow Change Speed

puci · December 21, 2024, 6:38pm

I try change follower plane speed with AIRSPEED_ params, but can not changing. I want to detect the leader plane on the follower plane’s camera. So I have to fly a little closer. The distance right now is 115m. The speed of both is 13 - 14m/s

Follower plane params (RIGHT):

AIRSPEED_CRUISE 20.0
AIRSPEED_MAX 30
AIRSPEED_MIN 10
AIRSPEED_STALL 0.0
FOLL_ALT_TYPE 0 # absolute
FOLL_DIST_MAX 20.0
FOLL_ENABLE 1 # Enabled
FOLL_OFS_TYPE 1 # Relative to lead vehicle heading
FOLL_OFS_X -20.0
FOLL_OFS_Y 20.0
FOLL_OFS_Z 0.0
FOLL_OPTIONS 0 # None
FOLL_POS_P 0.10000000149011612
FOLL_SYSID 0
FOLL_YAW_BEHAVE 1 # Face Lead Vehicle

Leader Plane params (LEFT):

AIRSPEED_CRUISE 12.0
AIRSPEED_MAX 30
AIRSPEED_MIN 9
AIRSPEED_STALL 0.0
FOLL_ALT_TYPE 0 # absolute
FOLL_DIST_MAX 100.0
FOLL_ENABLE 1 # Enabled
FOLL_OFS_TYPE 1 # Relative to lead vehicle heading
FOLL_OFS_X 0.0
FOLL_OFS_Y 0.0
FOLL_OFS_Z 0.0
FOLL_OPTIONS 0 # None
FOLL_POS_P 0.10000000149011612
FOLL_SYSID 0
FOLL_YAW_BEHAVE 1 # Face Lead Vehicle

timtuxworth · December 21, 2024, 8:36pm

The follow parameters only apply on the follow plane. They have no effect on the leader.

The obvious problem is FOLL_SYSID on the follow plane- this should be the SYSID_THISMAV of the leader plane. The leader plane and follow plane must have different SYSID_THISMAV values.

The other problem I see is FOLL_DIST_MAX - this will stop following as soon as the follow plane is > 100m from the leader. Definitely not what you want. You should set this to something large like 1000.

If you are running the plane_follow.lua script you should also have a set of ZP* parameters - please post those.

timtuxworth · December 21, 2024, 8:37pm

Please read the “readme”.md file for plane_follow:

github.com

ArduPilot/ardupilot/blob/db44c238f72dabde31a6d6dcc6c18123be65700e/libraries/AP_Scripting/applets/plane_follow.md

# Plane Follow

This script implements follow functionality for Plane. The plane must be
flying in Guided mode and will trigger on a scripting switch. The target plane
must be connected via MAVLink and sending mavlink updates to the chase plane
running this script. The MAVLINK_SYSID of the target must be set in FOLL_SYSID,
and must be different from the MAVLINK_SYSID of the following plane.


# Parameters

The script adds the following parameters to control it's behaviour. It uses 
the existing FOLL parameters that are used for the Copter FOLLOW mode. In addition
the following "ZPF" parameters are added: Z = scripting, P = Plane, F = Follow, in two
banks ZPF and ZPF2.

## ZPF_FAIL_MODE

This is the mode the plane will change to if following fails. Failure happens
if the following plane loses telemetry from the target, or the distance exceeds

This file has been truncated. show original

puci · December 21, 2024, 10:01pm

timtuxworth:

This script implements follow functionality for Plane. The plane must be
flying in Guided mode and will trigger on a scripting switch. The target plane
must be connected via MAVLink and sending mavlink updates to the chase plane
running this script. The MAVLINK_SYSID of the target must be set in FOLL_SYSID,
and must be different from the MAVLINK_SYSID of the following plane.

The result is the same as the old values. Still far away in distance(115m). I write with Python (pymavlink). I use mission_item_send() command.

Follower:
SYSID_ENFORCE 0 # NotEnforced
SYSID_MYGCS 255
SYSID_THISMAV 1
FOLL_ALT_TYPE 0 # absolute
FOLL_DIST_MAX 1000.0
FOLL_ENABLE 1 # Enabled
FOLL_OFS_TYPE 1 # Relative to lead vehicle heading
FOLL_OFS_X -10.0
FOLL_OFS_Y 10.0
FOLL_OFS_Z 0.0
FOLL_OPTIONS 0 # None
FOLL_POS_P 0.10000000149011612
FOLL_SYSID 2
FOLL_YAW_BEHAVE 1 # Face Lead Vehicle

Leader:
SYSID_ENFORCE 0 # NotEnforced
SYSID_MYGCS 255
SYSID_THISMAV 2
FOLL_ENABLE 0 # Disabled

timtuxworth · December 21, 2024, 11:16pm

Do you have the script installed? where are the ZP* parameters?

puci · December 22, 2024, 12:36pm

When I say ‘param show ZP*’ I don’t get any output. I connect via UDP in Python code, not a Lua script, and enter the latitude, longitude and altitude values of the plane (ROS2 topic) as parameters to the MAV_CMD_NAV_WAYPOINT command with Pymavlink mission_item_send(). Since I’m running ROS2 Humble, it’s constantly doing this in a loop. He follows but cannot get close.
Follower:
GUIDED> param show ZP*
GUIDED>

Leader:
CIRCLE> param show ZP*
CIRCLE>

timtuxworth · December 22, 2024, 4:43pm

Ah! Follow mode is not fully implemented in Plane, hence my script. If you look at my plane_follow.lua script, I had to add some logic, including two PID controllers to get the follow plane to correctly match the speed of the leader.

If you are trying to implement this in python or ROS2, you have a lot of work to do.

puci · December 22, 2024, 5:22pm

Thanks, I will try to do it with PID control.