MAVLink Communication

this page is under construction, and for the moment mainly serves the author as reference

In addition to the serial commands, the STorM32 controller also understands MAVLink messages, as defined in the MAVLink standard.

The STorM32 controller in fact integrates two MAVLink components, which in the following will be referred to as MAVLink Gimbal and as MAVLink Camera.

• The MAVLink Gimbal is the part which deals with the gimbal operation.
• The MAVLink Camera is related to the NT Camera, and is the part which offers a camera protocol micro service.

MAVLink Gimbal

In order to enable the MAVLink Gimbal, the emission of a heartbeat must be enabled by setting the Mavlink Configuration parameter accordingly.

The STorM32's system ID and component ID can be adjusted in the GUI. The defaults are

• Mavlink System ID = “1”
• Mavlink Component ID = “154” (= MAV_COMP_ID_GIMBAL)

The System ID should be matched to the system ID of the autopilot. The Component ID should usually not be changed.

The STorM32 supports MAVLink1 and MAVLink2, which can be set via the parameter Mavlink Version. Per default MAVLink2 is enabled, which should be the correct choice for most cases.

The following MAVLink commands are supported:

MAVLINK_MSG_ID_HEARTBEAT (#0, 0x00)

See HEARTBEAT.

The emission of the heartbeat needs to be activated in the GUI via the Mavlink Configuration parameter. The heartbeat is emitted at 1 Hz, with the following values:

• type: MAV_TYPE_GIMBAL (= 26)
• autopilot: MAV_AUTOPILOT_INVALID (= 8)
• base_mode: either 0 or MAV_MODE_FLAG_SAFETY_ARMED (= 0x80)
• custom_mode: STATE value of the o323bgc firmware
• system_status: either MAV_STATE_BOOT (= 1) or MAV_STATE_ACTIVE (= 4)

MAVLINK_MSG_ID_PARAM_REQUEST_READ (#20, 0x14)

See PARAM_REQUEST_READ.

MAVLINK_MSG_ID_PARAM_REQUEST_LIST (#21, 0x15)

See PARAM_REQUEST_LIST.

MAVLINK_MSG_ID_PARAM_VALUE (#22, 0x16)

See PARAM_VALUE.

MAVLINK_MSG_ID_PARAM_SET (#23, 0x17)

See PARAM_SET.

MAVLINK_MSG_ID_ATTITUDE (#30, 0x1E)

See ATTITUDE.

The emission of the attitude message with 2 Hz can be activated in the GUI via the Mavlink Configuration parameter, or by requesting a data stream with MESSAGE_INTERVAL. The yaw angle is relative to the forward direction.

MAVLINK_MSG_ID_RC_CHANNLES (#65, 0x41)

See RC_CHANNELS.

MAVLINK_MSG_ID_REQUEST_DATA_STREAM (#66, 0x42)

See REQUEST_DATA_STREAM.

This message is sent out with req_stream_id = MAV_DATA_STREAM_RC_CHANNELS and req_message_rate = 10, when an ArduPilot autopilot (= MAV_AUTOPILOT_ARDUPILOTMEGA) is detected.

MAVLINK_MSG_ID_COMMAND_LONG (#76, 0x4C)

See COMMAND_LONG.

Each command is acknowledged with a COMMAND_ACK message. The following commands are supported (parameter fields not mentioned are ignored):

MAV_CMD_DO_SET_PARAMETER (#180, 0xB4)
* param1 = parameter index
* param2 = parameter value

MAV_CMD_DO_SET_SERVO (#183, 0xB7)
* param2 = pwm value (only 700...2300 accepted)

MAV_CMD_DO_DIGICAM_CONFIGURE (#202, 0xCA)
Is just there so that a COMMAND_ACK with MAV_CMD_ACK_OK is returned

MAV_CMD_DO_DIGICAM_CONTROL (#203, 0xCB)
* param5 = shot (0 = off, 1 = IRSHUTTER)

MAV_CMD_DO_MOUNT_CONFIGURE (#204, 0xCC)
* param1 = mount_mode (0 = MAV_MOUNT_MODE_RETRACT and 1 = MAV_MOUNT_MODE_NEUTRAL recenters the camera)

MAV_CMD_DO_MOUNT_CONTROL (#205, 0xCD)
* param1 = pitch, angle in degree (COMMENT: the sign is opposite to convention!)
* param2 = roll, angle in degree
* param3 = yaw, angle in degree (COMMENT: the sign is opposite to convention!)
* param7 = mount_mode (0 = MAV_MOUNT_MODE_RETRACT and 1 = MAV_MOUNT_MODE_NEUTRAL recenters the camera)

MAV_CMD_DO_SET_CAM_TRIGG_DIST(#206, 0xCE)
* param3 = trigger camera once immediately (0 = off, 1 = IRSHUTTER)

MAV_CMD_PREFLIGHT_STORAGE (#245, 0xF5)
* param1 = parameter storage
     0: restore parameter values from EEPROM
     1: store parameter values in EEPROM
     2: ignored, as it maybe harmful

MAV_CMD_PREFLIGHT_REBOOT_SHUTDOWN(#246, 0xF6)
* param4
     1: restart with full reset
     2: ishut down motors

MAV_CMD_SET_MESSAGE_INTERVAL (#511, 0x01FF)
* param1 =  MAVLink message ID; the attitude and mount status can be requested
* param2 = interval between two messages, in microseconds; set to -1 to disable

MAV_CMD_REQUEST_MESSAGE (#512, 0x0200)
* param1 = message ID of the requested message  
     30: send attitude
     158: send mount status
     265: send mount orientation

MAV_CMD_REQUEST_PROTOCOL_VERSION (#519, 0x0207)
  send PROTOCOL_VERSION message 

MAV_CMD_REQUEST_AUTOPILOT_CAPABILITIES (#520, 0x0208)
  send AUTOPILOT_VERSION message

MAVLINK_MSG_ID_COMMAND_ACK (#77, 0x4D)

See COMMAND_ACK.

MAVLINK_MSG_ID_AUTOPILOT_VERSION (#148, 0x94)

See AUTOPILOT_VERSION.

MAVLINK_MSG_ID_MOUNT_STATUS (#158, 0x9E)

ArduPilot specific message. See MOUNT_STATUS.

The emission of the mount status message with 2 Hz can be activated in the GUI via the Mav Configuration parameter, or by requesting a data stream with MESSAGE_INTERVAL. The yaw angle is relative to the forward direction. The target is set to:

* target_system: 0
* target_component: 0

MAVLINK_MSG_ID_AUTOPILOT_VERSION_REQUEST (#183, 0xB7)

ArduPilot specific message. See AUTOPILOT_VERSION_REQUEST.

MAVLINK_MSG_ID_MESSAGE_INTERVAL (#244, 0xF4)

See MESSAGE_INTERVAL.

The attitude, the mount status, or the mount orientation can be requested.

MAVLINK_MSG_ID_STATUSTEXT (#253, 0xFD)

See STATUSTEXT.

This message is sent out after a PARAM_REQUEST_LIST has been served, and provides firmware and board type information.

MAVLINK_MSG_ID_MOUNT_ORIENTATION (#265, 0x109)

See MOUNT_ORIENTATION.

The emission of the mount orientation message with 2 Hz can be activated in the GUI via the Mav Configuration parameter, or by requesting a data stream with MESSAGE_INTERVAL. The yaw angle is relative to the forward direction.

MAVLINK_MSG_ID_PROTOCOL_VERSION (#300, 0x12C)

See PROTOCOL_VERSION.

MAVLink Camera

The MAVLink Camera is independent on the MAVLink Gimbal. That is, it can be used also then the MAVLink Gimbal is disabled (Mavlink Configuration = “no heartbeat”).

The system ID and MAVLink version of the MAVLink Camera is identical to the above, i.e., also determined by the parameters Mavlink System ID and Mavlink Version.

The component ID is adjusted by the setting Mavlink Camera, which also enables the MAVLink Camera.