apis.md

Introduction

This project includes a self-contained cross-platform library to retrieve data from the quadrotor and send the control commands. You can use this library for a simulated drone in Unreal engine or on a real quadrotor such as a MavLink based vehicle platform (and very soon DJI quadrotors such as Matrice).

Hello Drone

Here's the taste of how you can use our APIs in C++: See also Python API if you prefer that language.

#include <iostream>
#include "control/RpcLibClient.hpp"

int main() 
{
    using namespace std;
    msr::airlib::RpcLibClient client;

    cout << "Press Enter to arm the drone" << endl; cin.get();
    client.armDisarm(true);

    cout << "Press Enter to takeoff" << endl; cin.get();
    client.takeoff(60);

    cout << "Press Enter to use offboard control" << endl; cin.get();
    client.requestControl();

    cout << "Press Enter to move 5 meters in x direction with 1 m/s velocity" << endl; cin.get();    
    auto position = client.getPosition(); // from current location
    client.moveToPosition(position.x() + 5, position.y(), position.z(), 1, 5*1);

    cout << "Press Enter to land" << endl; cin.get();
    client.land();

    return 0;
}

You can find a ready to run project in HelloDrone folder in the repository.

How does Hello Drone work?

Hello Drone uses the RPC client to connect to the RPC server that is automatically started by the AirSim. The RPC server routes all the commands to a class that implements DroneControlBase. In essence, DroneControlBase defines our abstract interface for getting data from the quadrotor and sending back commands. We currently have concrete implementation for DroneControlBase for MavLink based vehicles. The implementation for DJI drone platforms, specifically Matrice, is in works.

Timing

Notice each method of DroneControlBase API takes one of two possible parameters: float duration or: float max_wait_seconds.

Methods that take float duration, like moveByVelocity return control immediately. So you can therefore choose to sleep for this duration, or you can change their mind and call something else which will automatically cancel the moveByVelocity.

Methods that take float max_wait_seconds, like takeoff, land, moveOnPath, moveToPosition, moveToZ, and so will block this amount of time waiting for command to be successfully completed. If the command completes before the max_wait_seconds they will return True, otherwise if the max_wait_seconds times out they will return False.

If you want to wait for ever pass a big number. But if you want to be able to interrupt even these commands pass 0 and you can do something else or sleep in a loop while checking the drone position, etc.

Note: We would not recommend interrupting takeoff/land on a real drone, of course, as the results may be unpredictable.

How to get images from drone?

Here's a sample code. For more information, please see DroneControlBase class. See Camera Views for information on the camera views and how to change them.

int playWithImages() 
{
    using namespace std;
    using namespace msr::airlib;
    
    msr::airlib::RpcLibClient client;

    vector<uint8_t> image = client.getImageForCamera(0, DroneControlBase::ImageType::Depth);
    //do something with images
}

Can I run above code on real quadrotors as well?

Absolutely! The AirLib is self-contained library that you can put on an offboard computing module such as the Gigabyte barebone Mini PC. This module then can talk to the flight controllers such as Pixhawk using exact same code and MavLink protocol (or DJI protocol). The code you write for testing in the simulator remains unchanged! See AirLib on custom drones.

What else can I do ?

You can also program AirSim using Python.

See move on path demo showing video of fast flight through Modular Neighborhood environment.

See building a hexacopter.

See building point clouds.