Unbalanced motor speed


#1

I have piloted my Rov2.8 some times ,it is really exciting .but i also find some problems.In low speed,for example ,i set the thrust speed to 2,the rov move directly forward well,but in high speed when the thrust speed set to 4 or 5,the Rov will not always move forward ,it move forward about 3-4 meters and then turn right.so i wander whether the ROV pilot for a few time the two motors‘s speed is not the same,then lead to the Rov turn right after a few seconds.so any ways to solve this problem ?


#2

Having the exact same thruster output is quite hard to achieve as it depends on a variety of different factors, like bearing friction, lubrication etc. Also slightly asymmetries in the fluild dynamics of the ROV lead significant drift. In case you have an IMU available you can activate the heading hold feature, which corrects the ROVs heading via the compass. This works extremely well for long straight lines.


#3

thank you very much,i got it ! All the information display on the cockpit seems to be same for the both motors.after I reading some issues on the Forum,i wonder if it is matter with the ESC Calibration?I have not do this on my ROV2.8KIT,is it necessary to do this ?How should i do if it is necessary?


#4

Hi Ckliyifen,

First I would check to make sure it is not a mechanical issue, such as corrosion on the bearing, by checking for resistance when you hand-turn the motors.
If there is no mechanical issue, a software update, firmware update and ESC calibration might be what your ROV needs.

In order to update your software and firmware please follow the instructions on this link:

The ESC’s 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