Autonomous ANAFI Piloting Using OpenCV and ArUco

levi.vandek · April 11, 2024, 1:37am

I am trying to control a Parrot ANAFI using a simple control algorithm. The goal is for the ANAFI to

1. Start a stream
2. Take off
3. Pan the gimbal downward
4. Identify an ArUco marker via image OpenCV library
5. Align itself to that marker using commands like PCMD() or moveBy()
6. Land

Each of these steps works until PCMD() or moveBy() is called. I know this is because these are blocking functions and so they interrupt the threads’ abilities to update global variables even if they are locked. Once the motion commands are called, the variables stop being updated and cannot be again. Below is the link to the repo containing the current iteration for the file. The file being used is a heavily edited version of the streaming example on the Olympe github. If anyone has advice, I would be greatly appreciative! The idea I had was more of a procedural while loop that employs a P-controller but it seems that will not work with the blocking commands I am using.

github.com

l-vande-k/drone_testing/blob/main/streaming_and_yaw_control.py

# not used but provided by the example??
import shlex
import subprocess
import tempfile

import cv2
import cv2.aruco as aruco


from olympe.messages.ardrone3.Piloting import TakeOff, Landing, PCMD
from olympe.messages.ardrone3.Piloting import moveBy
from olympe.messages.ardrone3.PilotingState import FlyingStateChanged
from olympe.messages.ardrone3.PilotingSettings import MaxTilt
from olympe.messages.ardrone3.PilotingSettingsState import MaxTiltChanged
from olympe.messages.ardrone3.GPSSettingsState import GPSFixStateChanged
import olympe.messages.gimbal as gimbal


# these libraries are used
import math

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levi.vandek · April 17, 2024, 9:56pm

Here is an updated version:

github.com

l-vande-k/drone_control_via_aruco/blob/main/loop_control_3.py


import math
import os
import queue
import uuid
import threading
import numpy as np
import time
import pickle
from array import *
import csv


import cv2
import cv2.aruco as aruco

import olympe
from olympe.messages.ardrone3.Piloting import TakeOff, Landing, PCMD
from olympe.messages.ardrone3.Piloting import moveBy
from olympe.messages.ardrone3.PilotingState import FlyingStateChanged

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If anyone could provide insight into how to use the PCMD piloting commands in the same kind of loop structure, it would be greatly appreciated.

Axelm · April 22, 2024, 9:50am

Hi @levi.vandek,

Sorry for the delay. You can simply remove the .wait() of the self.drone(move.extended_move_by(…)) function. You can check the result of the moveby() with the expectation object returned by self.drone(move.extended_move_by(…)).

There is the documentation about the Olympe expectation objects and an example of an adanced Olympe expectation usage.

Regards.

levi.vandek · April 23, 2024, 3:14pm

Thank you for your recommendation! I have tried that in the past and the position and orientation of the drone does not change. The .wait() is required for creating any changes in the drone’s state. Do you know why this could be?

Axelm · April 25, 2024, 9:55am

Hi @levi.vandek,

You need to manage the asynchronous expectation to move the drone. Take a look at the documentation about the Olympe expectation objects and an example of an adanced Olympe expectation usage.

Regards,
Axel