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Strange setup of motros

(Nikos Maurommatis) #1

Hi everybody,

I think i need some help with my setup of the motors. I dived the BR2 for the first time a week ago and I had a very strange behavior during the steering:
– At the right stick of the gamepad a) instead of ASCEND and DESCEND I had ROLL movement (move of stick forward/reverse) and b) instead of yaw no movement at all with motors working (move of stick right/left).
– At the left stick of the gamepad a) instead of FORWARD and REVERSE I had YAW movement (move of stick forward/reverse) and b) the LATERAL MOVEMENT was right (move of stick right/left).

Coming back to my home and have done a lot of tests I have ended up with the corrections:
Motor1 => reverse
Motor2 => reverse
Motor6 => reverse
With the above setup all the sticks and movements are right, except I have no LATERAL movement at the left stick.

I have double checked the propellers (CW / CCW), the penetrators of the motors and the cables from the motors to the ESC. I don’t know the physical mapping of the ESCs to the Pixhawk channels so I can’t check them.

Can anybody to help?

Best,
Nikos

(Dale) #2

Nikos,
did you check the direction of airflow through the motors (the build manual is helpful here)

I have just completed the first test run of our BR2. I found the same as you for motors 5 and 6. I’d installed them the wrong way around, so that I got roll rather than down or up.

I checked 1,2,3, and 4 by watching the direction of thrust of each of the motors.

Have a close look at the direction of spin, and prop type when you input a lateral control. What direction is the thrust for each of the four motors?

The manual could be improved to show thrust direction for each of the motors. Happy to write it up.

(Nikos Maurommatis) #3

@Dale_A, I will check the direction for each of the four motors and I let you know.

I have found the connections diagram (I use BlueROV2 with no-red-wire ESCs - 2018 and later) but I have a question: the ESC U6 is for the thruster 1, U7 for the thruster 2 etc?

Nikos

(devis) #4

Hi,

I have the same issue as you with the motors 5 and 6. I have swap the green and the blue cable on the controler’s 5.

(Jacob) #5

Hello, this problem arises when the ‘Configure motor directions’ step is not conducted during the software setup. Please follow these instructions again carefully, and let us know if you continue to have issues.

The direction of the motor rotation is dependent on how the three phases of the motor are physically connected to the ESCs (if any two wires are swapped, the direction of rotation will flip). Because we cannot guarantee what order the phases are connected, the motor directions must be configured in software.

How to validate the correct direction of rotation for each engine?
(Nikos Maurommatis) #6

Hi, I am still trying to figure out what is wrong…

Is this picture from above the vehicle or from below the vehicle?

image

Nikos

(Rusty) #7

Hi Nikos, this picture is from above (top-down view).

(Nikos Maurommatis) #8

@rjehangir thank you.

(Dale) #9

Nikos,
my install was the same, so motors five and six installed as CW, and CCW. All leads connected white blue green matching in the connectors.

On first test, the machine rolled, rather than descended/ascended. I used GC to reverse 6, and then it worked.

Looking at the plan view above, I realise that I installed the motors the opposite way to the drawing, i.e, I took it to be a view from below.

That being said, it only took swapping direction for either 5 or 6 to get vertical movement, rather than roll.

(Nikos Maurommatis) #10

@Dale_A, I think I have solved the setup. The major problem was I had installed the thrusters looking at the picture of thrusters from below (that was why the thrusters 5, 6 needed change). Instead, of changing all thrusters, I have changed the channels at Pixhawk.
I think everything is working fine now but tomorrow I wll go to the sea for the final test.

May I ask you, if you have any problem with LATERAL movement? Because, that was my biggest problem and not the ROLL.

Nikos

(Dale) #11

Nikos,
I had no problem with lateral movement at all. I did the same as you, installed the thrusters as looking below.

Run the ROV on the bench, and observe thrust (air direction) when a lateral command is given. Have an observer note the spin, and thus thrust direction for each thruster. A short dab of the controls is enough to just get the motors spinning, rather than full power.