ROV continuously yawing – same firmware, params, and hardware

Blue Robotics Software ArduSub
1

Hi blue robotics team,

Our ROV has started continuously yawing in one direction in Manual and Stabilize modes, even with no joystick input.

What’s confusing is that nothing has changed since the last test:

  • Pixhawk 2.4.7 (Pixhawk1 / FMUv2)

  • ArduSub 4.5.7 (ChibiOS)

  • Vectored 6DOF – 8 thrusters

  • Same parameter file

  • Same thrusters, wiring, ESCs, and hardware

It worked perfectly in the previous pool test, but now it spins continuously in yaw.

Things we already checked:

  • Reloaded the same params file

  • Verified thruster wiring and direction

  • Re-did accel/gyro calibration

  • Confirmed no joystick yaw input

Since it happens even in Manual mode, we’re unsure what could cause this.

Any ideas on what we should check next?

2

Hi @Ferbin -
Can you share how you confirmed no joystick input? Did you disable the joystick and arm with your GCS software?
How did you calibrate the Gyro - do you mean the accelerometer and compass? Does the compass indicate the vehicle is spinning during the behavior?

Sharing a .bin autopilot log would be helpful.. To me, it sounds like a controller got wet and is sending yaw input even when the sticks are centered - a quick thing to check if nothing else!

3

1.] I turned off the joystick input and tried arming the ROV. Yet the robot was still spinning (uncontrollably).

2.] For the IMU callibration, I followed the instructions from QGC ( placing it still(Gyro) , rotating it in the desired direction (Accel, compass))

3.] I have attached the .bin (log)

log_127_UnknownDate.bin (3.8 MB)

log_102_UnknownDate.bin (2.2 MB)

4

Did you find anything weird with the log files I send ?

5

Hi @Ferbin -
Yes - it looks like the 127 log shows that the vehicle was in Acro mode (??) where joystick input changes the rate of motion in an access. That, along with rcin4 (yaw) being at 1300 initially to me indicates something strange is going on.

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The compass calibration may not be very good, as I don’t see evidence it was “spinning continuously in yaw” ? I’m also a bit surprised to see evidence of the motor direction test mode - were you setting up the motors in this log?

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The second log is also unhelpful - it does not include vehicle modes, and is very short, with a turn only a few degrees to one side.

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A longer log, or a .tlog, would help further troubleshoot. Confirming your joysticks aren’t sending unexpected signals with a website like this is also a good thing to check.

6

Hi @Ferbin -

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If this is a standard BlueROV2, the AHRS_ROTATION parameter should be roll90 - we find that it is 0 in your parameters file, from the log. Perhaps you didn’t correctly load the default Heavy parameters in BlueOS?

If that’s not the issue, then your motors may not be connected to the correct output channels - you can verify manually, running each thruster with a slider from the PWM outputs page. and making sure the thruster highlighted in the 3D graphic is the one that is spinning.