Hello, my team and I recently assembled a Blue ROV2 and established QGround Control. After running tests out of water we tested it in a small pool. Robot will descend, ascend, yaw and move side to side correctly.
However, it will not move forward and backward. We pulled it out of the water to see how it would run on dry land, and it appears that only 2 motors are working at a time. Going forward motors 1 and 4 would run, and going backward motors 2 and 3 would run. When we use depth hold mode, it would hold for a moment then begin to roll to the side. We believe these are issues with calibration and not motor position.
Also, we set up and calibrated the Subsea Gripper. It was working fine during our first test 2 days ago, but now it has stopped working. It would make a clicking sound when we hit the button, but would not move.
Is there any advice you can offer to remedy these issues?
First off, I assume that you checked the functionality and thrust direction of each Thruster using the “Configure Motor Direction” instructions in the BR Software Setup Instructions. If you did and all six Thrusters performed correctly, then skip the following steps as you apparently have some other issue that the following steps will not identify.
Secondly I would check and make sure that the three wire ESC servo cables are connected and oriented correctly to the Pixhawk servo output connectors.
Next make sure that the three wires from each thruster are connected correctly to the ESC terminal block connections.
Hello Tina, Please revisit our software setup instructions, and make sure you complete them in order and in their entirety. Pay particular attention to the joystick and motor setup sections.
Thank you! We were able to fix the motor calibration as well as the gripper.
I have another question regarding water temperature. We plan on running a wet test at an outdoor location where the water temperature is expected to be at a low of 37 degrees Fahrenheit. The technical specifications state that the ROV2 can operate in 32 degree water.
Should this be a concern for the robot or the 18Ah batter we are using?
Are there any additional launch steps we should take into consideration regarding these temps?
This should be fine, lithium-ion batteries are generally good to discharge in temperatures down to -20°C, though capacity will diminish. Make sure not the charge below freezing, the temperature should be well above 0°C to safely take a charge. You can find more details on this here.
I would recommend allowing the ROV to acclimate to the ambient temperature for a few minutes before submerging it in order to reduce the thermal shock and stress on the parts.