Write Your First App

applicaThis example app assembles a flight mode, which will automatically register itself in APX4 and become available in AMC when running. When activated, this flight mode example app holds the current 3D position of the vehicle by setting the desired horizontal acceleration, vertical velocity and the yaw heading rate to zero.

1. Code structure

Create a new directory for this app:

mkdir -p my-app/src
cd my-app

Create a minimal CMakeLists.txt file:

cmake_minimum_required(VERSION 3.8)
project(my_app)

# find dependencies
find_package(ament_cmake REQUIRED)
find_package(auterion_sdk REQUIRED)

add_executable(my_app src/my_app.cpp)

ament_target_dependencies(
  my_app
  auterion_sdk
)

Create a source file src/my_app.cpp:

This illustrates the structure of custom flight mode using the SDK, and does not represent a practical use case for a flight mode.

#include <auterion_sdk/auterion.hpp>
#include <auterion_sdk/control/multicopter/local_frame_dynamics_control.hpp>
#include <iostream>
#include <functional>

class MyMode {
private:
    auterion::Mode _mode;


public:
    explicit MyMode(auterion::SDK& sdk) : _mode(sdk, "My Mode", {
        auterion::multicopter::LocalFrameDynamicsSetpoint::Config{}
    }) {
        _mode.onActivate([]() {
            // initilize your controller here, like integrators, ramps, etc.
            std::cout << "My mode activated" << std::endl;
        });

        _mode.onDeactivate([]() {
            std::cout << "My mode deactivated" << std::endl;
        });

        _mode.onUpdateSetpoint([](float dt_s) -> auterion::multicopter::LocalFrameDynamicsSetpoint {
            return auterion::multicopter::LocalFrameDynamicsSetpoint()
                .withHorizontalAcceleration(Eigen::Vector2f(0.0f, 0.0f))
                .withVerticalVelocity(0.0f)
                .withHeadingRate(0.0f);
        });
    }
};

int main(int argc, char* argv[]) {
    auterion::SDK sdk(argc, argv, "flight_mode_example");

    MyMode my_mode(sdk);

    sdk.run();

    return 0;
}

This sets up the minimal structure for a local-frame-dynamics mode for a Multicopter.

You can now run the app locally, with the commands

source /opt/ros/humble/setup.sh
cmake -B build -S.
cmake --build build

2. Make it into an AuterionOS app

Turning this example code into an AuterionOS app is done using the App Framework. Make sure to have the tooling set up before continuing. In particular the helper tool auterion-cli should be installed on the machine that is used to build the app.

Create a Dockerfile to build your app image:

FROM auterion/app-base:v2

RUN curl -1sLf 'https://dl.cloudsmith.io/public/auterion/public/setup.deb.sh'| sudo -E bash
RUN apt update && apt install -y ros-humble-auterion-sdk

COPY src /app/src
COPY CMakeLists.txt /app
WORKDIR /app
RUN . /opt/ros/humble/setup.sh && \
    cmake -B build -S . && cmake --build build

CMD . /opt/ros/humble/setup.sh && /app/build/my_app

Create the auterion-app.yml metadata file:

AuterionOS app API Version v3 or later is required to support Auterion SDK. For more details on the apps API see Apps API

auterion-api-version: 3
auterion-app-base: v2

app-name: local-frame-dynamics-mode
app-author: <com.your-company>
app-version: 0.0.1
target-platform: skynode

services:
  my-mode: 
    build: .

Now, you can build and install your app on Skynode:

auterion-cli app build
auterion-cli app install

Virtual Skynode

If you are building your app for Virtual Skynode, you must provide the --simulation flag to your build arguments to specify the correct simulation target architecture:

auterion-cli app build --simulation

This is explained in the Application Development page.