I was wondering if anyone can give me some input on the autopilot capabilities of BLUEROV2. Can it hold lateral position against a half knt current?
Case in point, I did a dive last night in a large NJ inlet. Conditions were murky and I was having difficulty navigating to my target. With the tidal current, I had to keep my current ROV in position by holding the tether (which is threaded through poly rope).
I’m not familiar with the software or inertial system of the BROV2, but is there a way to have it self compensate to more or less hold position with the autopilot software? GPS doesn’t work under water, but can it hold surface position prior to a dive?
EDIT: I just read a post by Magnus about this, I see there are still some challenges here, would it be possible to use GPS for surface position holding, then when submerged, rely on inertial?
My first open water test of the BlueROV2 was with about 10 knots of side wind and an outgoing tide, so I would guess at least half a knot of current. With the thruster gain set to 50% gain I had no problem maintaining position. With gain set to its lowest setting, it was just able to maintain position. That’s using manual control of the ROV’s position.
One feature that might be useful in current is “input hold” (not 100% sure what it’s called) which holds the controls at whatever joystick positions you have it at when activated. If the current and heading remain steady, this might help.
The ArduSub and Pixhawk support GPS input, which would feed position information while the ROV is on the surface, but I’m not sure its accuracy will be good enough for an accurate position hold. Kevin has been experimenting with this and hopefully will join in with some feedback.
The simplest thing to do now is to use the “Input Hold” joystick button feature. When pressed, this will set the current inputs as the trim. So, if you are going forward into a current at 0.5 knots and you press “Input Hold”, the ROV will continue going forward at 0.5 knots, even with the joysticks centered. If you push forward, it will go faster, if you pull back it will go slower.
To reset back to normal controls, center the joysticks and press “Input Hold” again and it will be back to normal.