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Verts start running as soon as Depth Hold mode is engaged


#1

When I engage Depth Hold, the vertical thrusters run with no vert command from pilot. Even occurs when pressure has been calibrated and the vehicle is not in the water.


(Jacob) #2

The motors will always run in any mode other than MANUAL. The problem is that the ROV is trying to correct the depth, but isn’t moving according to the sensor in air.


#3

Roger. Thanks Jacob


(Rusty) #4

@gcelec, just FYI, this will also happen in Stabilize Mode if the ROV is moved in such a way that the system tries to correct for it. For instance, if you have the ROV in air and you turn it 90deg, it will turn on the thrusters to try to turn back and they will keep running since they can’t actually cause it to turn.


#5

Thanks for the advice Rusty. If I engage Stability Mode while the vehicles on the floor, the thrusters don’t run unless I move the vehicle, which makes sense. I thought that Depth Mode would be the same i.e. the vertical thrusters wouldn’t run until the depth changed, so when they started running as soon as DM was engaged, it didn’t make sense.


(Jacob) #6

There is a ‘ceiling’ for the ROV that exists ~5cm beneath the surface of the water. This prevents the ROV from trying to fly out of the water in depth hold mode. The ROV is trying to get below that ceiling. Besides that, even if the depth is off by a millimeter or the angle off by a fraction of a degree, the ROV will try to fix it. These sorts of tiny errors could be introduced by variation of the sensor readings.