connect

R2026b

Connect MAVLink client to UDP or serial port

Syntax

connectionName = connect(mavlink,type)

connectionName = connect(___,Name=Value)

Description

connectionName = connect(mavlink,type) connects the MAVLink client mavlink using the connection type specified by type.

connectionName = connect(___,Name=Value) specifies one or more options using name-value arguments in addition to the input arguments from the previous syntax. For example, LocalPort=50791 specifies to connect the MAVLink client to UDP port 50791.

Examples

Establish Serial Connection with Pixhawk Board

Connect a local MAVLink client to a serial port and establish communication with a Pixhawk^® 4 board running PX4^® firmware by exchanging heartbeat messages.

Create a mavlinkdialect object using the common.xml file.

dialect = mavlinkdialect("common.xml");

Create a local MAVLink client by using the mavlinkio object.

gcs = mavlinkio(dialect);

Store the remote MAVLink client information by using the mavlinkclient object. This code stores information for a Pixhawk board with a system ID of 1 and a component ID of 1.

uav = mavlinkclient(gcs,1,1)

uav = 
  mavlinkclient with properties:

         SystemID: 1
      ComponentID: 1
    ComponentType: "Unknown"
    AutopilotType: "Unknown"

Connect the local MAVLink client to the same serial port as the Pixhawk board by using the connect function. In this code, the Pixhawk board uses the "COM5" port.

connect(gcs,"Serial",SerialPort="COM5");

Create a heartbeat microservice object.

heartbeat = mavlinkmicroservice(gcs,"heartbeat");

Start sending heartbeat messages to the Pixhawk board by using the start function.

start(heartbeat,uav,"Serial",SerialPort="COM5")

If the Pixhawk board replies with heartbeat messages, the local MAVLink client establishes a connection to it.

Verify that a connection has been established by using the listClients function. Note that the heartbeat messages include the ComponentType and AutopilotType information of the Pixhawk board.

listClients(gcs)

ans = 2×4 table
    SystemID    ComponentID       ComponentType             AutopilotType     
    ________    ___________    ____________________    _______________________

      255            1            "MAV_TYPE_GCS"        "MAV_AUTOPILOT_INVALID"
       1             1         "MAV_TYPE_QUADROTOR"       "MAV_AUTOPILOT_PX4"

Verify that the ComponentType and AutopilotType properties of the mavlinkclient object have been automatically updated to match the heartbeat message values.

uav

uav = 
  mavlinkclient with properties:

         SystemID: 1
      ComponentID: 1
    ComponentType: "MAV_TYPE_QUADROTOR"
    AutopilotType: "MAV_AUTOPILOT_PX4"

To stop the connection, first stop the heartbeat message stream.

stop(heartbeat,uav)

Then, disconnect the local MAVLink client from the serial port.

disconnect(gcs)

Connect Simulated UAV to QGroundControl Through UDP Connection

Connect a local MAVLink client to QGroundControl by exchanging heartbeat messages over UDP,

Open QGroundControl.

Create a mavlinkdialect object using the common.xml file.

dialect = mavlinkdialect("common.xml");

Create a local MAVLink client that represents a simulated UAV by creating a mavlinkio object with these settings:

• MAVLink message definition — dialect

• MAVLink system ID — 1

• MAVLink component ID — 1

• MAVLink component type — MAV_TYPE_QUADROTOR

• MAVLink autopilot type — MAV_AUTOPILOT_GENERIC

uav = mavlinkio(dialect,SystemID=1,ComponentID=1,AutopilotType="MAV_AUTOPILOT_GENERIC", ...
    ComponentType="MAV_TYPE_QUADROTOR");

Store the remote MAVLink client information that represents QGroundControl. By default, QGroundControl has a system ID of 255 and a component ID of 190.

qgc = mavlinkclient(uav,255,190);

Connect the local MAVLink client to a UDP port by using the connect function.

connect(uav,"UDP");

Verify that the local MAVLink client has connected to a UDP port by using the listConnections function.

connectionTable = listConnections(uav)

connectionTable = 
   1x2 table
       ConnectionName         ConnectionInfo     
       ______________      ___________________ 
   
        "Connection1"      "UDP@0.0.0.0:55371"

Create a heartbeat microservice object.

heartbeat = mavlinkmicroservice(uav,"heartbeat");

Specify the host address and port of QGroundControl.

qgcHost = "127.0.0.1";
qgcPort = 14550;

Start sending heartbeat messages to QGroundControl by using the start function.

start(heartbeat,qgc,"UDP",RemoteHost=qgcHost,RemotePort=qgcPort);

If QGroundControl replies with heartbeat messages, the local MAVLink client establishes a connection to it.

Verify that the connection has been established by using the listClients function.

listClients(uav)

ans = 2×4 table
    SystemID    ComponentID       ComponentType             AutopilotType     
    ________    ___________    ____________________    _______________________

      255           190          "MAV_TYPE_GCS"        "MAV_AUTOPILOT_INVALID"
       1             1        "MAV_TYPE_QUADROTOR"     "MAV_AUTOPILOT_GENERIC"

To stop the connection, first stop the heartbeat message stream.

stop(heartbeat,gcs)

Then, disconnect the local MAVLink client from the UDP port.

disconnect(uav)

Input Arguments

mavlink — Local MAVLink client

mavlinkio object

Local MAVLink client, specified as a mavlinkio object.

type — Connection type

"UDP" | "Serial"

Connection type, specified as one of these options:

• "UDP" — Connects the local MAVLink client to a UDP port. Specify the UDP port number using the LocalPort argument. If you do not specify the port number, the connect function connects the local MAVLink client to a random open UDP port.

• "Serial" — Connects the local MAVLink client to a serial port. You must specify the serial port name using the SerialPort argument.

Data Types: char | string

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: connect(mavlink,"UDP",LocalPort=50791) specifies to connect the MAVLink client to UDP port 50791.

ConnectionName — Connection identifier

character vector | string scalar

Connection identifier, specified as a character vector or string scalar. By default, the function assigns a connection identifier of "ConnectionN", where N is an integer that starts at 1 and increases with each connection created, including named connections and connections that have been disconnected.

Data Types: char | string

LocalPort — UDP port number

0 (default) | integer in the range [0, 65535]

UDP port number, specified as an integer in the range [0, 65535]. To specify this argument, you must specify type as "UDP". If you specify LocalPort as 0, connect function connects the MAVLink client to a random open local port.

SerialPort — Serial port name

"" (default) | character vector | string scalar

Serial port name, specified as a character vector or string scalar. To specify this argument, you must specify type as "Serial".

Tip

To get a list of serial ports on your system, use the serialportlist function, or press tab when you specify the SerialPort argument.

Example: "COM2"

Data Types: char | string

BaudRate — Serial port baud rate

57600 (default) | positive scalar

Serial port baud rate, specified as a positive scalar. To specify this argument, you must specify type as "Serial".

EnableFlowControl — Data flow control method

"none" (default) | "hardware" | "software"

Data flow control method for a serial connection, specified as one of these options. To specify this argument, you must specify type as "Serial".

• "none" — Do not use data flow control.

• "hardware" — Use hardware handshaking to control data flow.

• "software" — Use software handshaking to control data flow.

Data Types: char | string

Parity — Parity bit mode

"none" (default) | "even" | "odd"

Parity bit mode for a serial connection, specified as "none", "even", or "odd". To specify this argument, you must specify type as "Serial".

Data Types: char | string

DataBits — Number of bits used to represent one character of data

8 (default) | 5 | 6 | 7

Number of bits used to represent one character of data for a serial connection, specified as 5, 6, 7, or 8. To specify this argument, you must specify type as "Serial".

StopBits — Number of stop bits

2 (default) | 1

Number of stop bits used for a serial connection, specified as 1 or 2. To specify this argument, you must specify type as "Serial".

Output Arguments

connectionName — Connection identifier

string scalar

Connection identifier, returned as a string scalar.

Data Types: string

Version History

Introduced in R2019a

R2026b: Connect MAVLink client to serial port

The connect function now enables you to connect a MAVLink client to a serial port by specifying the type argument as "Serial". You can also configure the serial connection by using the SerialPort, BaudRate, EnableFlowControl, Parity, DataBits, and StopBits name-value arguments.