Send MAVLink command with MATLAB

Hello, I'm searching if there is a way for interact and send commands to my quadcopter with MATLAB, instead of a Ground Control Station. I tried with MATMAV but seems not working. I also tried with MAVLink Support and also this seems not working for send command to my quadcopter. This is my code:

dialect = mavlinkdialect('common.xml');

mavlink = mavlinkio(dialect);

connect(mavlink, 'UDP', 'LocalPort', 14550);

%%

client = mavlinkclient(mavlink, 1, 1) % specify client (1 client = 1 drone)

connectionList = listConnections(mavlink)

clientsList = listClients(mavlink)

topicsList = listTopics(mavlink)

%%

message_num = 400;

cmdMsg = createcmd(dialect, 'int', message_num)

cmdMsg

num2enum(dialect,"MAV_CMD", message_num)

%%

sendudpmsg(mavlink, cmdMsg, '0.0.0.0', 14550)

There are other approaches to send commands to quadcopter through MATLAB?

Thanks in advance!

Answer 1

[Jianxin Sun]

Hi Paolo,

First the mavlink message needs to be refined:

For arm UAV:

cmd = dialect.createcmd("LONG", "MAV_CMD_COMPONENT_ARM_DISARM");

cmd.Payload.target_component(:) = 1;

cmd.Payload.target_system(:) = 1;

cmd.Payload.param1(:) = 1;

For disarm UAV

cmd = dialect.createcmd("LONG", "MAV_CMD_COMPONENT_ARM_DISARM");

cmd.Payload.target_component(:) = 1;

cmd.Payload.target_system(:) = 1;

cmd.Payload.param1(:) = 0;

Also since you are emulating a ground control station in MATLAB, you will need to keep sending out heartbeat from MATLAB to help the UAV find it:

heartbeat = createmsg(dialect,"HEARTBEAT");

heartbeat.Payload.type(:) = enum2num(obj.Dialect,'MAV_TYPE', 'MAV_TYPE_GCS');

heartbeat.Payload.autopilot(:) = enum2num(obj.Dialect,'MAV_AUTOPILOT', 'MAV_AUTOPILOT_INVALID');

heartbeat.Payload.system_status(:) = enum2num(obj.Dialect,'MAV_STATE',"MAV_STATE_STANDBY");

heartbeatTimer = timer;

heartbeatTimer.ExecutionMode = 'fixedRate';

heartbeatTimer.TimerFcn = @(~,~)sendmsg(obj.IO,heartbeat);

start(heartbeatTimer);

If UAV is also broadcasting its heartbeat, your listClient call should show UAV client as well, then you can send message to the uav client:

sendmsg(mavlink, client);

[Paolo]

Hi @Jianxin Sun, thanks for the reply. I figured out how the general mechanism. Thanks for the help!

[vahe]

Hi @Jianxin Sun, can you help me?

I have written the following codes to monitor gimbal variables for UAV through Mavlink codes in MATLAB:

--------------------------------------------------------------------

dialect = mavlinkdialect('common.xml');

sender = mavlinkio(dialect,'SystemID',1,'ComponentID',1,...
    'AutopilotType',"MAV_AUTOPILOT_GENERIC",...
    'ComponentType',"MAV_TYPE_FIXED_WING");

connect(sender,'UDP');

destinationPort = 14551;
destinationHost = '127.0.0.1';

receiver = mavlinkio(dialect);

connect(receiver,'UDP','LocalPort',destinationPort);

info = msginfo(dialect,"GIMBAL_DEVICE_ATTITUDE_STATUS");

msg = createmsg(dialect,info.MessageName);

info.Fields{:};

subscriber = mavlinksub(receiver,'GIMBAL_DEVICE_ATTITUDE_STATUS',...
                        'NewMessageFcn',@(~,msg)disp(msg.Payload));

for msgIdx = 1:10
    sendudpmsg(sender,msg,destinationHost,destinationPort);
    pause(1/50);
end

--------- in the command window ------

time_boot_ms: 0

q: [0 0 0 0]

angular_velocity_x: 0

angular_velocity_y: 0

angular_velocity_z: 0

failure_flags: 0

flags: 0

target_system: 0

target_component: 0

---------------------------------------------

--------- But how can I show only 'q' in the command window?

Because I want to convert it to Euler angles = quat2eul(q)

Answer 2

[Michal]

Hi, I see in this topic were were answering people who might help me resolve the issue.

I am opening the SITL Simulation in Mission Planner (Simulation Tab -> Mulitrotor).

My aim is to setup a Bidirectional Mavlink2 communication between Matlab and Mission Planner simulation. I want to be able to send commands from Matlab to MP and se the behaviour of the dron.

I am able to receive forwarded messages from Mission Planer. I set up Ctrl + F, then open Connection to 14552 Port.

However if I want to send something Back, Mission Planner dose not see it. In Mavlink Inspector I can see only

Vechicle 1

- Comp 1 MAV_COMP_ID_AUTOPILOT1

Mechicle 255

- Comp 190 MAV_COMP_ID_MISSIONPLANNER

The code below I use to try to send a HEARTBEAT messages to Mission Planner.

% === CONNECTION CONFIGURATION ===
localPort = 14552;       % Local UDP port (match SITL config)
targetSys = 1;
targetComp = 1;
% === Initialize MAVLinkIO ===
dialect = mavlinkdialect("common.xml", 2);
mav = mavlinkio(dialect);
connect(mav, "UDP", "LocalPort", localPort);
% === Create drone target client ===
client = mavlinkclient(mav, targetSys, targetComp);
% === Register MATLAB as GCS client (sysid 255, compid 1) ===
gcs = mavlinkclient(mav, 255, 1);
% === Subscriptions for responses ===
ackSub = mavlinksub(mav, client, "COMMAND_ACK");
statustextSub = mavlinksub(mav, client, "STATUSTEXT");
% === Send HEARTBEATs periodically ===
disp("📡 Sending HEARTBEAT every 1 second...");
heartbeat = createmsg(dialect, "HEARTBEAT");
heartbeat.Payload.autopilot = 8;  % MAV_AUTOPILOT_INVALID
heartbeat.Payload.base_mode = 0;
heartbeat.Payload.custom_mode = uint32(0);
heartbeat.Payload.system_status = 0;
heartbeat.Payload.type = 6;       % MAV_TYPE_GCS (Ground Station)
duration = 30;  % seconds
startTime = tic;

while toc(startTime) < duration
    sendmsg(mav, heartbeat);
    fprintf("❤️ Sent HEARTBEAT at t=%.1f sec\n", toc(startTime));
    pause(1.0);
end

% === Check COMMAND_ACKs ===
ackMsgs = latestmsgs(ackSub, 1);
for i = 1:numel(ackMsgs)
    fprintf("✅ COMMAND_ACK: cmd=%d, result=%d\n", ...
        ackMsgs(i).Payload.Command, ackMsgs(i).Payload.Result);
end

% === Check STATUS_TEXTs ===
statusMsgs = latestmsgs(statustextSub, 1);
for i = 1:numel(statusMsgs)
    txt = native2unicode(char(statusMsgs(i).Payload.Text'), 'UTF-8');
    txt = erase(txt, char(0));
    fprintf("📥 STATUS: [%d] %s\n", ...
        statusMsgs(i).Payload.Severity, strtrim(txt));
end

% === Cleanup ===
disconnect(mav);
delete(mav);
disp("✅ Done");

I do not know how to solve it. Maybe I have to switch something in Mission Planner, but it is not clear to me what. Is it possible to set a connection I would like to have. All help will be appreciated.

[Jianxin Sun]

Here is an example sending message to port 14552:

% === CONNECTION CONFIGURATION ===
remotePort = 14552;       % Remote UDP port (match SITL config)
targetSys = 1;
targetComp = 1;
% === Create IO object in MATLAB as GCS client (sysid 255, compid 1) ===
gcs = mavlinkio("common.xml", SystemID=255, ComponentID=1);
gcs.connect("UDP")
% === Create drone target client ===
client = mavlinkclient(gcs, targetSys, targetComp);
% === Subscriptions for responses ===
ackSub = mavlinksub(gcs, client, "COMMAND_ACK");
statustextSub = mavlinksub(gcs, client, "STATUSTEXT");
% === Send HEARTBEATs periodically ===
disp("📡 Sending HEARTBEAT every 1 second...");
heartbeat = createmsg(gcs.Dialect, "HEARTBEAT");
% It is important to preserve the field data type using (:)= assignement
heartbeat = createmsg(gcsNode.Dialect,"HEARTBEAT");
heartbeat.Payload.type(:) = enum2num(dialect,'MAV_TYPE',gcsNode.LocalClient.ComponentType);
heartbeat.Payload.autopilot(:) = enum2num(dialect,'MAV_AUTOPILOT',gcsNode.LocalClient.AutopilotType);
heartbeatTimer = timer;
heartbeatTimer.ExecutionMode = 'fixedRate';
heartbeatTimer.TimerFcn = @(~,~)sendserialmsg(gcsNode,heartbeat,uavSerialPort);
start(heartbeatTimer);

% If you haven't sent any command, you probably won't receive any command
% ack or status message either. You probably need to start with sending
% command or request parameter, etc.
% === Request parameters ===
paramValueSub = mavlinksub(gcs,client,'PARAM_VALUE','BufferSize',100,...
                            'NewMessageFcn', @(~,msg)disp(msg.Payload));
msg = createmsg(gcs.Dialect,"PARAM_REQUEST_LIST");
msg.Payload.target_system(:) = targetSys;
msg.Payload.target_component(:) = targetComp;
sendmsg(gcs,msg,client)

% === Cleanup ===
stop(heartbeatTimer);
delete(heartbeatTimer);
disconnect(mav);
delete(mav);
disp("✅ Done");