RC_SUB_ACTION is an enumeration that defines the operational state of remote control (RC) channel input handling in a drone control system.
It determines how RC commands from a transmitter (TX) are processed and whether they are passed through, modified, or overridden by software.

This enum is used to manage the autonomy level of RC input—ranging from fully released (no input sent) to active joystick control (direct channel override)—and plays a key role in safety and automation logic, especially during mode transitions like switching to guided flight.

Definition

92:105:drone_engage/drone_engage_mavlink/src/defines.hpp
typedef enum RC_SUB_ACTION 
{
    // No RC channel data is sent to the drone.
    RC_SUB_ACTION_RELEASED                      =   0,
    
    // Center values (1500 µs) are sent; physical TX has no effect.
    RC_SUB_ACTION_CENTER_CHANNELS               =   1,
    
    // Last known RC values are frozen and continuously sent.
    RC_SUB_ACTION_FREEZE_CHANNELS               =   2,
    
    // Live RC channel values from software (e.g. app) are sent.
    RC_SUB_ACTION_JOYSTICK_CHANNELS             =   4,
    
    // Velocity commands sent instead of raw RC; used in guided mode.
    RC_SUB_ACTION_JOYSTICK_CHANNELS_GUIDED      =   8
} RC_SUB_ACTION;

Type: enum (C++ scoped enumeration)
Purpose: Controls how RC input is applied to the drone’s flight controller
Used in: ANDRUAV_VEHICLE_INFO::rc_sub_action to reflect current RC override state
Values are powers of two or sequential integers, suggesting possible bitmask use or simple state tracking
Initial value: Set to RC_SUB_ACTION_RELEASED during initialization

The enum is tightly coupled with RC override logic, where physical transmitter input can be disabled in favor of software-generated commands—critical for autonomous or app-controlled flight.

Example Usages

One primary use is initializing the RC state when the system starts:

249:251:drone_engage/drone_engage_mavlink/src/fcb_main.cpp
de::fcb::mission::CMissionManager::getInstance().getAndruavMission().clear();

// Initialize RC override state to released (no input sent)
m_andruav_vehicle_info.rc_sub_action = RC_SUB_ACTION::RC_SUB_ACTION_RELEASED;

Another key usage is in parsing incoming commands from a remote source (e.g. mobile app):

420:422:drone_engage/drone_engage_mavlink/src/fcb_andruav_message_parser.cpp
int rc_sub_action = cmd["b"].get<int>();

// Interpret integer command as RC_SUB_ACTION enum
m_fcbMain.adjustRemoteJoystickByMode((RC_SUB_ACTION)rc_sub_action);

Here, the JSON field "b" carries the desired RC mode, which is cast directly into the RC_SUB_ACTION enum and dispatched to control logic.

Overall usage pattern:
RC_SUB_ACTION is used across 12 files, primarily in:

defines.hpp: Definition and vehicle state struct
fcb_main.cpp: State machine logic for RC handling
fcb_andruav_message_parser.cpp: Incoming command parsing
fcb_main.hpp: Method signature for adjustRemoteJoystickByMode()

It is central to remote control override systems, especially in scenarios involving app-based joystick control, geofencing, or autonomous mission execution.

Notes

RC_SUB_ACTION_JOYSTICK_CHANNELS_GUIDED is specifically intended for guided mode flight, where velocity commands (not raw PWM) are sent—this enables smoother autonomous maneuvers.
The enum values skip 3 and 5–7, suggesting possible future extensions or alignment with bitmask-style flags (though not currently used as bitflags).
Despite being called “joystick”, this system does not require a physical joystick—it refers to software-emulated RC inputs from apps or tracking systems.

Definition

Example Usages

Notes

See Also