OpenROV 2.8 constantly dragging to the left


#1

Hi all ROV’ers!

I have an OpenROV 2.8 with HD upgrade that just have been assembled, and I have just started testing it in the water.
However, when I put it forward, the ROV is dragging to left, after about 30 seconds it will have turned 360 degrees around.
When I’m compensating to the right with the joystick the ROV is going somewhat straight forward, but I always have to jog the joystick to the left/right to keep it on track.
Any suggestion to what the cause of this can be?

–Thomas


#2

I have heard of this and am experiencing the same time of problem. I believe it to be a problem with the port motor not turning as fast as the starboard motor. It may be an issue with drag in the motor itself. I am not aware of any way to actually count RPM or to add a compensation factor in the software. I will be searching the forum for possible answers but wanted to reach out to you and let you know you are not alone with this issue.


#3

Hmm…
Sounds like there might be a problem with the ESC?
I will try to get hold of a tachometer and see if I can count the RPM of the propellers.

Is it the Afro ESC that are used on the 2.8?
Any tip on how to calibrate?

–Thomas


#4

I had the same problem with mine.

The issue ended up being the quality (or lack thereof) of the motor. I replaced the starboard side motor, and the issue was gone.

Mine came with turnigy motors, and I think the quality of them varies greatly from one to another.I’m not sure if that is what is still supplied with the kits or not?


#5

The motors are usually the cause. Other causes can be very unbalanced drag and ESCs losing their programming. Here’s a little bit of info that might help get folks on the right path:

  1. if it’s still pulling left or right, check that both motors turn relatively freely by hand. They can be a little different from each-other but major differences could indicate a physical problem.

  2. In the settings or diagnostics pane there is a motor slider, you can enter a value and see if that in both the port and starboard motors and check how it flies from there.

  3. If these are not working it could be the motor or the esc (hard to tell). Let’s try reflashing the esc.

////
The ESC’s (electronic speed controllers) don’t share the same firmware as the Arduino on the Controller board.
In order to flash your ESC’s manually, follow these instructions:

Download PuTTY. It is a program that allows you to manually connect to an IP address via a terminal window.
When you run the program, connect to the IP address: 192.168.254.1
If there is no connectivity issues due to hardware, or your computers static IP address, it should open a terminal window.

Type in the following lines of code:

cd /opt/openrov/cockpit/linux

sudo bash install-afro-esc-firmware.sh

power cycle the ROV and see if that does anything
////

  1. just to make sure it’s not drag or some other cause, you can move the left motor to the right and conversely. Fly it forward using the W key (not a gamepad) at low or medium thrust factor. That will rule out any hydrodynamic issues. You’ll have to swap them back (don’t do any soldering or disconnecting of wire just yet) so you don’t have reversed controls left and right.

  2. It’s probably the motor. Give support@openrov.com a quick email or head over to https://store.openrov.com/collections/components/products/motor-s