Hi Everyone,

I´m seeking assistance to adopt ArduCopter further towards autonomous surfaced and submerged operation of a Russian Oscar II class RC submarine. I have successfully managed to run the boat in stabilize mode in the horizontal plane for course keeping using APM 2.6 and ArduCopter - but I´m facing difficulties running even the surfaced boat despite good GPS connectivity in Auto mode.

Hardware

Oscar II class SSBN (scale 1:100)

acrylic pipe pressure hull

aluminum tech rack

static diving system (2 piston tanks)

3 diving conditions - surfaced - submerged - parking on ground

dual prop drive system (2 x C35-30-45 300kv)

automatic depth & pitch control - APM independent

Futaba FX 18 40 MHz 8 CH TX

ACT DSL DSQ 8 CH RX

ArduMega 2.6 (3DR)

external compass / GPS unit (3DR U-blox Neo6)

power module (3DR)

bi-directional telemetry (433 MHz - 3DR)

ArduCopter V 3.0.1

Jeti BEC powering APM output

Configuration in ArduCopter as "classical helicopter"

Wiring RX / APM

RX 1 > APM 1

RX 2 > APM 2 throttle

RX 3 > APM 8

RX 4 > APM 4 rudder

RX 5 > APM 5 mode switch

RX 6 > APM 3

RX 4 connected to APM in and out CH 4 = tail rotor output > connected to rudder servo (Futaba  digital 251T) - all other CH are connected directly to servos etc. - connection APM via Y-cable - but no device  on APM output side - flooding of piston tanks causes desired pressure build up within the pressure hull (+1200 mbar) - APM onboard barometric sensor reads expected altitude of minus (!) 1200 m due to overpressure within the hull - 3-channel switch shifts between stabilize and auto mode - GPS tracks 11 sats surfaced - 8 to 9 sats shallow submerged (conning tower just below the surface) - compass function ok - arming OK - excellent course keeping qualities surfaced and submerged in stabilize mode - I can even run the boat perfectly straight on just the port or starboard engine.

Problem

I am not able to get Auto-mode operational - way-points are set in MP or MP 2.0 - waypoint altitude voluntarily set to negative values (100 mbar below the negative reading of baro sensor) to convince the APM that current altitude at take off is already "above" waypoint altitude - or positive values - engaging the motors makes the boat travels just ahead without taking course to WP one - no indication on MP flight plan screen "traveling to WP1" - however: I can choose the command "Go to here" and rudder shifts in the appropriate direction.

Question

- does Auto Mode strictly require positive values?

- could Auto Mode be modified to ignore baro readings thus facilitating take off at any barometric height? 

- does Auto Mode require motor(s) connected via BL controller(s) to APM?

- is it possible to override baro measurements manually from within MP to set -1200 mbar as take off altitude?

- any other settings that I need to work on?

I appreciate everyones interest and willingness reading up to the end.

Regards,

E=mc2