Sub Modes

Sub has the following modes:

legend for requirements: P - needs Position(GPS,etc.), D - needs Depth sensor, R - needs Rangefinder

Mode	Description	Requires
MANUAL	Pilot control with no stabilization	-
ACRO	Body-frame rate control, manual depth control	-
STABILIZE	Manual angle control, manual depth control	-
ALT_HOLD	Stabilize with automatic depth control	D
AUTO	Automatic mission command list execution	P/D
GUIDED	Swim to location or velocity/direction using GCS	P/D
CIRCLE	Circle swim with depth control	P/D
SURFACE	Return to surface, pilot directional control	-
POSHOLD	Loiter with depth control and pilot overrides	P/D
MOTOR_DETECT	Automatically determine motor rotation and adjust	-
SURFTRAK	Hold distance above seafloor while stabilizing	R

See Pilot Control for more details on modes.

Mode Details

ACRO Mode

• ACRO_RP_P

• ACRO_YAW_P

• ACRO_BAL_ROLL

• ACRO_BAL_PITCH

• ACRO_TRAINER

• ACRO_EXPO

Stabilization Related

• ATC_ANGLE_MAX

• JS_GAIN_DEFAULT

ALT_HOLD Mode

• SURFACE_MAX_THR

Depth Control Related

• SURFACE_DEPTH

• PILOT_SPD_UP

• PILOT_SPD_DN

• PILOT_SPEED

Auto/Guided Waypoint Navigation Related

• WP_SPD

• WP_RADIUS_M

• WP_SPD_UP

• WP_SPD_DN

• WP_ACC

• WP_ACC_Z

• WP_RFND_USE

• WP_YAW_BEHAVIOR

GUIDED Mode

In GUIDED mode the vehicle is commanded by a GCS, companion computer or Lua script. Position, velocity and acceleration targets can be sent using SET_POSITION_TARGET_LOCAL_NED or SET_POSITION_TARGET_GLOBAL_INT, with the type_mask field selecting which of the three are being supplied. The accepted combinations are:

• position only

• velocity only

• position and velocity

• position, velocity and acceleration

Any other combination, such as velocity with acceleration, is ignored.

A target that includes velocity describes one point on a moving trajectory: where the vehicle should be, and how it should be moving, at the moment the message is received. It is not a destination to stop at. Between messages the target keeps moving: its position advances by the target velocity, and its velocity changes by the target acceleration. The vehicle follows this moving target, so targets would normally be sent several times per second along the desired path. For example, a target with a forward acceleration makes the vehicle start speeding up immediately, rather than when it reaches the target position. Because the velocity and acceleration move the target position, they never conflict with it: a velocity pointing away from the sent position simply moves the target away from that position.

The vehicle’s speed and acceleration while following the target, including the target’s own velocity and acceleration, are limited by WP_SPD, WP_SPD_UP, WP_SPD_DN, WP_ACC and WP_ACC_Z. A target that moves faster than these limits is followed with a lag.

If no new target is received for 3 seconds, the velocity and acceleration targets are set to zero and the vehicle holds the last target position. To swim to a location and stop there, send a position-only target, which uses waypoint navigation at WP_SPD.

Lua scripts can send the same targets with vehicle:set_target_posvelaccel_NED(), and can offset the vehicle’s current target using the poscontrol bindings, poscontrol:set_posvelaccel_offset() and poscontrol:get_posvelaccel_offset(). The guided_above_terrain_posvelaccel_sub.lua example script uses these to swim at a constant forward speed while holding a set height above the seafloor.

CIRCLE Mode

• CIRCLE_RADIUS_M

• CIRCLE_RATE

• CIRCLE_OPTIONS

Mode Selection

By default modes are controlled via MAVLink command from the GCS or companion computer, or by Joystick Buttons. But RC control can be enabled by setting:

• RC_PROTOCOLS not equal to zero (“1” is usually used)

• FLTMODE_CH to the RC channel which will control swim mode selection

• FLTMODE1 - FLTMODE6 to desired Swim Mode