Hey! I have build a ROV for a local competition, since I built it with HDPE parts it’s really unstable. So I want to use stabilize mode on QGroundControl, for that I had to do accelerometer calibration but I’m facing some issues. When I do calibration (with none or custom option) vehicle starts to go crazy on stabilize mode, which option should I choose? Thanks. (I’m using Raspberry Pi 4, Pixhawk PX4 and 8 thrusters with ESCs)
Hi @yamancakaroglu -
If your vehicle “goes crazy” in stabilize mode, then thrusters are not set to be the correct direction, or in the position, that the autopilot expects. Verify via the motor test page that each motor is in the expected location for your frame type, and turns the expected direction when triggered. If your vehicle is in the water, you can use the auto-direction function to do this quickly for supported frame types!
Hey! Thanks for the reply. I have checked the thruster directions suitable for my frame type and it’s correct. I think the problem is about accelerometer calibration.
Hi @yamancakaroglu
Does the artificial horizon and compass heading reflect the orientation of the vehicle? Is it static with the vehicle sitting still, and level when the vehicle is? You may need to adjust your Autopilot_Orientation parameter
I never tried or checked those before. I’ll check those as soon as possible, thanks!
Hi @tony-white, I hope you’re doing well, I solved the issue with calibration, it works perfectly fine! But my only issue is when I try to go up under the water with stabilize mode, nose instantly goes up and the back side of the ROV starts to sink. I think it’s related to propeller directions, can you help me on that? Btw ROV perfectly performs right, left and bottom movements. Thanks.
Hi @yamancakaroglu -
With the ROV in the air, when you push down (dive) with the joystick, do all vertical thrusters blow air upwards? If not, you simply need to change the direction of the motors that are blowing the wrong way. Keep in mind, CW and CCW propellers are used to balance the rotary forces, and should occur in equal numbers as shown in the color code of the ArduSub frame types!
To change a motor direction, you can either adjust in the Vehicle Setup page in BlueOS, or swap any two of the three motor wires.
Hi! It’s actually blows air to upwards. I’m normally changing thruster directions via qgroundcontrol but I have cw and ccw thurester propellers, should I change it physically? Thanks.
Hi @yamancakaroglu -
You never answered - is the artificial horizon showing the vehicle level when it is level? Did you adjust the autopilot-orientation parameter?
Have you run the automatic motor direction test?
I never tried adjusting the parameter, can you guide me on that please? Artificial horizon works perfectly. When I try automatic direction test, it says thruster 1 failed. Thanks.
Hi @yamancakaroglu -
If the Horizon looks correct with the vehicle level, than you don’t need to adjust that parameter.
Did you conduct the automatic direction configuration with the vehicle floating freely in the water? It will fail otherwise.
I tried automatic direction in the water but it fails on thruster 1 or 5 every single time.
Hi @yamancakaroglu -
What frame type are you using for your vehicle?
It sounds as if thruster 1 and 5 are either not mounted in the expected orientation, or are spinning the wrong direction. The process may also fail if the vehicle cannot move freely.
I’m using 8 thrusters (6DOF) frame type and I’m pretty sure that thrusters placed correctly.
Hi @yamancakaroglu -
Sorry for the hassle! If the ESCs for each thruster is connected to the correct channel, has the correct prop, and moves in the expected direction when triggered in manual mode (fwd/reverse and up/down), I’m “pretty sure” you shouldn’t be having any issues!
If you’re still stumped after reviewing your connections and placement, sharing a video of the behavior may be helpful. If the vehicle moves as expected in Manual mode, Stabilize or Depth Hold should not result in any unexpected movement!
Please verify you’re running BlueOS 1.3.1 stable, and ArduSub 4.1.2 as listed here.
Thank you very much for your help! I’ll share the video later today.