Flight Modes

This article provides an overview and links to the available flight modes for Blimp.

Overview

Blimp has 5 built-in flight modes.

Flight modes are controlled through the radio (via a transmitter switch), or using commands from a ground station (GCS) or companion computer.

The table below shows for each flight mode whether it provides altitude or position control, and whether it requires valid position information from a sensor (typically a GPS) in order to arm or switch into this mode.

Mode	Alt Ctrl	Pos Ctrl	Pos Sensor Required	Summary
Land	-	-	No	Stops all actuators.
Manual	m	m	No	Manual output via motor/servo mixer.
Velocity	s	s	Yes	Stick positions set a desired velocity. Mostly intended for tuning.
Loiter	s	s	Yes	Holds altitude and position.
RTL	s	s	Yes	Returns to position/altitude set when first armed (Home) and sets 0deg YAW

Symbol	Definition
m	Manual control
s	Pilot controls desired position/velocity to controller

Recommended Flight Modes

It is best to start with manual mode to ensure the the actuators and rc controller have been set up correctly (i.e. pushing the pitch stick forward does make the blimp move forward).

Once this is confirmed, you can switch into VELOCITY mode. This uses only the velocity PID controller, thus allowing tuning this controller using the VEL* parameters. Test whether centering the sticks results in a standstill and no oscillation. Also test that the blimp reaches a set velocity reasonably quickly.

After this stage, you can switch into LOITER mode and check its performance. Generally the position controller should need less tuning (using the POS* parameters), but some tuning may still be needed.

LAND mode stops all servo outputs so that the Blimp will stop moving. It can also be used as a pilot selected mode to save battery if the blimp needs to wait. Note that since the blimp is still floating, it is likely to drift with the wind, though it is recommended to have the blimp slightly negatively buoyant so that the blimp will also go down and “land” when in this mode.

Most transmitters can be setup to provide a 3 position switch that can be set up to quickly switch between the most-used flight modes but you can find instructions here for setting up a 6-position flight mode switch.

GNSS Receiver (“GPS”) Dependency

Flight modes that use positioning data require valid position prior to takeoff. When using GPS, to verify if your autopilot has acquired GPS lock, connect to a ground station or consult your autopilot’s hardware overview page to see the LED indication for GPS lock.

Below is a summary of position identification dependency for Copter flight modes. Most often this position information is obtained via a GPS, but other position sensors, such as 3D cameras or beacons, may be used and would need to provide a valid location, for those modes requiring it, prior to arming.

Requires valid position prior to takeoff:

• VELOCITY

• LOITER

Do not require position information:

• MANUAL

• LAND

Pilot Control

Pilot control in each mode (Except LAND in which there is no pilot control and all servo outputs are stopped) , if the default RC_MAP_xxxx parameters are used, is as follows:

TRANSMITTER STICK	CONTROL EFFECT
ROLL	MANUAL: Lateral movement, VELOCITY: Full throw attempts to obtain LOIT_MAX_VELY m/s laterally, LOITER: Moves the target position laterally (see note below)
PITCH	MANUAL: Fore/Aft movement, VELOCITY: Full throw attempts to obtain LOIT_MAX_VELX m/s fore/aft, LOITER: Moves the target position fore/aft (see note below)
YAW	MANUAL: Yaw, VELOCITY: Full throw attempts to increase/decrease heading LOIT_MAX_VELYAW radians/s, LOITER: Full throw attempts to increase/decrease heading LOIT_MAX_POSYAW radians/s
THROTTLE	MANUAL: Ascend/Descend, VELOCITY: Full throw attempts to increase/decrease altitude LOIT_MAX_VELZ m/s, LOITER: Full throw attempts to increase/decrease altitude LOIT_MAX_POSZ m/s

Note

In LOITER, roll and pitch stick inputs are relative to the vehicle’s heading (or to north if SIMPLE_MODE is enabled). At full throw, LOIT_MAX_POSX and LOIT_MAX_POSY limit how fast the target position moves north/south and east/west respectively, in m/s.